Patent Publication Number: US-2022211546-A1

Title: Eustachian tube dilation balloon with ventilation path

Description:
PRIORITY 
     This application is a continuation-in-part of U.S. patent application Ser. No. 12/777,856, filed on May 11, 2010 (published on Oct. 28, 2010 as U.S. Pub. No. 2010/0274188), which is a continuation-in-part of U.S. patent application Ser. No. 12/649,078, filed on Dec. 29, 2009 (published on Aug. 5, 2010 as U.S. Pub. No. 2010/0198191), which is a continuation-in-part of U.S. patent application Ser. No. 12/340,226, filed on Dec. 19, 2008 (published on Jun. 25, 2009 as U.S. Pub. No. 2009/0163890), which claims the benefit of U.S. Provisional Pat. App. No. 61/015,647, filed on Dec. 20, 2007. All the disclosures of the above listed references are hereby incorporated by reference in their entirety for all purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention is related to methods and systems for accessing, diagnosing and treating target tissue regions within the middle ear and the Eustachian tube. 
     Referring to  FIGS. 1-2 , the ear  10  is divided into three parts: an external ear  12 , a middle ear  14  and an inner ear  16 . The external ear  12  consists of an auricle  18  and ear canal  20  that gather sound and direct it towards a tympanic membrane  22  (also referred to as the eardrum) located at an inner end  24  of the ear canal  20 . The middle ear  14  lies between the external and inner ears  12  and  16  and is connected to the back of the throat by a Eustachian tube  26  which serves as a pressure equalizing valve between the ear  10  and the sinuses. The Eustachian tube  26  terminates in a distal opening  28  in the nasopharynx region  30  of the throat  32 . In addition to the eardrum  22 , the middle ear  14  also consists of three small ear bones (ossicles): the malleus  34  (hammer), incus  36  (anvil) and stapes  38  (stirrup). These bones  34 - 38  transmit sound vibrations to the inner ear  16  and thereby act as a transformer, converting sound vibrations in the canal  20  of the external ear  12  into fluid waves in the inner ear  16 . These fluid waves stimulate several nerve endings  40  that, in turn, transmit sound energy to the brain where it is interpreted. 
     The Eustachian tube  26  is a narrow, one-and-a-half inch long channel connecting the middle ear  14  with the nasopharynx  30 , the upper throat area just above the palate, in back of the nose. The Eustachian tube  26  functions as a pressure equalizing valve for the middle ear  14  which is normally filled with air. When functioning properly, the Eustachian tube  26  opens for a fraction of a second periodically (about once every three minutes) in response to swallowing or yawning. In so doing, it allows air into the middle ear  14  to replace air that has been absorbed by the middle ear lining (mucous membrane) or to equalize pressure changes occurring on altitude changes. Anything that interferes with this periodic opening and closing of the Eustachian tube  26  may result in hearing impairment or other ear symptoms. 
     Obstruction or blockage of the Eustachian tube  26  results in a negative middle ear pressure  14 , with retraction (sucking in) of the eardrum  22 . In adults, this is usually accompanied by some ear discomfort, a fullness or pressure feeling and may result in a mild hearing impairment and head noise (tinnitus). There may be no symptoms in children. If the obstruction is prolonged, fluid may be drawn from the mucous membrane of the middle ear  14 , creating a condition referred to as serous otitis media (fluid in the middle ear). This occurs frequently in children in connection with an upper respiratory infection and accounts for the hearing impairment associated with this condition. 
     A lining membrane (mucous membrane) of the middle ear  14  and Eustachian tube  26  is connected with, and is the same as, the membrane of the nose  42 , sinuses  44  and throat  32 . Infection of these areas results in mucous membrane swelling which in turn may result in obstruction of the Eustachian tube  26 . This is referred to as serous otitis media, i.e. essentially a collection of fluid in the middle ear  14  that can be acute or chronic, usually the result of blockage of the distal opening  28  of the Eustachian tube  26  which allows fluid to accumulate in the middle ear  14 . In the presence of bacteria, this fluid may become infected, leading to an acute suppurative otitis media (infected or abscessed middle ear). When infection does not develop, the fluid remains until the Eustachian tube  26  again begins to function normally, at which time the fluid is absorbed or drains down the tube into the throat  32  through the Eustachian tube opening  28 . 
     Chronic serous otitis media may result from longstanding Eustachian tube blockage, or from thickening of the fluid so that it cannot be absorbed or drained down the Eustachian tube  26 . This chronic condition is usually associated with hearing impairment. There may be recurrent ear pain, especially when the individual catches a cold. Fortunately, serous otitis media may persist for many years without producing any permanent damage to the middle ear mechanism. The presence of fluid in the middle ear  14 , however, makes it very susceptible to recurrent acute infections. These recurrent infections may result in middle ear damage. 
     When the Eustachian tube  26  contains a build-up of fluid, a number of things will occur. First, the body absorbs the air from the middle ear  14 , causing a vacuum to form which tends to pull the lining membrane and ear drum  22  inward, causing pain. Next, the body replaces the vacuum with more fluid which tends to relieve the pain, but the patient can experience a fullness sensation in the ear  10 . Treatment of this condition with antihistamines and decongestants can take many weeks to be fully effective. Finally, the fluid can become infected, which is painful and makes the patient feel ill and which may cause the patient not to be able to hear well. If the inner ear  14  is affected, the patient may feel a spinning or turning sensation (vertigo). The infection is typically treated with antibiotics. 
     However, even if antihistamines, decongestants and antibiotics are used to treat an infection or other cause of fluid build-up in the middle ear  14 , these treatments will typically not immediately resolve the pain and discomfort caused by the buildup of fluid in the middle ear  14 ; i.e. the most immediate relief will be felt by the patient if the fluid can be removed from the Eustachian tube  26 . 
     Antibiotic treatment of middle ear infections typically results in normal middle ear function within three to four weeks. During the healing period, the patient can experience varying degrees of ear pressure, popping, clicking and fluctuation of hearing, occasionally with shooting pain in the ear. Resolution of the infection occasionally leaves the patient with uninfected fluid in the middle ear  14 , localized in the Eustachian tube  26 . 
     Fluid build-up caused by these types of infections has been treated surgically in the past. The primary objective of surgical treatment of chronic serous otitis media is to reestablish ventilation of the middle ear, keeping the hearing at a normal level and preventing recurrent infection that might damage the eardrum membrane and middle ear bones. 
     For example, as shown in  FIG. 3 , a myringotomy can be performed to relieve fluid in the middle ear  14 . A myringotomy is an incision  42  in the eardrum  22  performed to remove fluid in the middle ear  14 . A hollow plastic tube  44 , referred to as a ventilation tube, is inserted and lodged in the incision  42  to prevent the incision  42  from healing and to ensure ventilation of the middle ear  14 . The ventilation tube  44  temporarily takes the place of the Eustachian tube  26  in equalizing the pressure in the middle ear  14 . The ventilation tube  44  usually remains in place for three to nine months during which time the Eustachian tube  26  blockage subsides. When the tube  44  dislodges, the eardrum  22  heals; the Eustachian tube  26  then resumes its normal pressure equalizing function. 
     Another method of relieving the pressure in the middle ear  14  is shown in  FIG. 4  in which a hypodermic needle  46  is driven through the eardrum  22  through which any accumulated fluid can be withdrawn from typically only the upper portion of the Eustachian tube  26 . 
     The methods of  FIGS. 3 and 4  involve rupturing the eardrum  22  to relieve the fluid accumulation and pressure increase in the middle ear. Neither of these methods, in addition to the sometimes permanent puncture created in the eardrum  22 , is especially effective in removing all of the fluid in the Eustachian tube  26  since often the lower end  28  thereof is blocked and dammed with fluid. 
     In connection with the above surgical treatments of  FIGS. 3 and 4 , Eustachian tube  26  inflation is also employed to relieve the pressure build-up and fluid accumulation as shown in  FIG. 5 . The hypodermic syringe  46  (shown with a flexible tip  48 ) is inserted into a nostril or into the mouth until the tip  48  is positioned adjacent the distal opening  28  of the Eustachian tube  26  in the nasopharynx region  30  of the throat  32 . Air is blown through the tip  48  via the syringe  46  into the obstructed Eustachian tube  26  and, thus, into the middle ear  14  to help relieve the congestion and reestablish middle ear ventilation. This procedure is often referred to as politzerization. Politzerization is most effective when one of the nostrils is pinched shut (as shown in  FIG. 6 ), while the patient simultaneously swallows. This forces air into the Eustachian tube  26  and the middle ear  14 . This technique is good for opening the Eustachian tube  26  but it does not clear accumulated fluid away. 
     Another method for clearing the middle ear  14  (at least temporarily) is referred to as the “valsalva” maneuver, accomplished by forcibly blowing air into the middle ear  14  while holding the nose, often called popping the ear. This method is also good for opening the Eustachian tube  26  but it does not clear the accumulated fluid away either. 
     Typical disorders associated with the middle ear and the Eustachian tube include perforated ear drums, tympanosclerosis, incus erosion, otitis media, cholesteotoma, mastoiditis, patulous Eustachian tube, and conductive hearing loss. To treat some of these disorders, ear surgery may be performed. Most ear surgery is microsurgery, performed with an operating microscope. Types of ear surgery include stapedectomy, tympanoplasty, myringotomy and ear tube surgery. 
     One of the simplest ear surgeries is the myringotomy or the incision of the ear drum. However, ear surgery can also require the removal of the tympanic membrane for the visualization of the middle ear space. Often surgeons will try to preserve the integrity of the membrane by making incisions in the skin of the ear canal and removing the tympanic membrane as a complete unit. Alternatively, middle ear access is achieved via the mastoids. This method approaches the middle ear space from behind the ear and drills through the mastoid air cells to the middle ear. Whether the bony partition between the external ear canal and the mastoid is removed or not depends on the extent of the disease. Canal-wall-down refers to the removal of this bony partition. Canal-wall-up refers to keeping this bony partition intact. The term modified radical mastoidectomy refers to an operation where this bony partition is removed and the eardrum and ossicles are reconstructed. A radical mastoidectomy is an operation where this bony partition is removed and the ear drum, malleus and incus bones are permanently removed so that the inner lining of the large cholesteotoma sac can be safely cleaned. This operation is done when an extensive cholesteotoma is encountered or one that is adherent to the inner ear or facial nerve. 
     Afflictions of the middle ear and Eustachian tube are very prevalent and a serious medical problem, afflicting millions of people and causing pain, discomfort and even hearing loss or permanent ear damage. Although a number of treatments have been developed, as described above each of them has shortcomings. Therefore, a need exists for improved methods and systems for accessing, diagnosing and treating target tissue regions within the middle ear and the Eustachian tube. Ideally, such methods and systems would be minimally invasive and pose very little risk of damage to healthy ear tissue. 
     SUMMARY 
     The embodiments of the present invention are directed toward methods and systems for accessing, diagnosing and treating target tissue regions within the middle ear and the Eustachian tube. 
     In one aspect, the present invention provides a method for accessing a Eustachian tube of a patient. The method may involve inserting a guide catheter into a nasal passage of the patient, the guide catheter having a distal tip with a bend having an angle between 30 and 90 degrees, and advancing the guide catheter in the nasal passage toward an opening of the Eustachian tube in the nasopharynx to place the distal tip adjacent the Eustachian tube opening. 
     In one embodiment, the method may also include advancing a diagnostic device through the guide catheter to place a distal tip of the diagnostic device adjacent the Eustachian tube opening. The diagnostic device may be a catheter or an endoscope. 
     In another embodiment, the method may involve introducing a diagnostic probe into the Eustachian tube to directly assess Eustachian tube function. The diagnostic probe may be made from a flexible and Eustachian tube compatible material. The diagnostic probe may be a pressure transducer located on a guidewire. The method may also include monitoring pressure within the Eustachian tube while the patient is swallowing, and assessing an opening function of the patient&#39;s Eustachian tube using the monitoring. 
     In one embodiment, the method may also involve removing the guide catheter after the diagnostic probe is placed into the Eustachian tube. 
     In one embodiment, the diagnostic probe may include an ultrasound probe. 
     In another embodiment, the method may also involve advancing a treatment device through the guide catheter toward the Eustachian tube to place a distal tip of the treatment device adjacent the Eustachian tube opening. The treatment device may comprise a distal radiopaque member. The treatment device may comprise a catheter. The treatment device may also comprise a fluid introduction device for introducing a fluid into a middle ear space of the patient&#39;s ear. The method may also involve scanning the middle ear space using an ultrasound device. The fluid may be air, a contrast medium, an aspiration fluid, or a drug. 
     In another embodiment, the treatment device may comprise an aspiration device for aspirating a substance from the middle ear space. 
     In another embodiment, the method may also involve introducing a protective device proximal the Eustachian tube, and monitoring advancement of the treatment device using the protective device. In one aspect, the protective device may comprise a sensor positioned proximal the tympanic membrane to sense the position of the treatment device during the advancement. The protective device may comprise an endoscope to visualize the advancement. 
     In another aspect, the present invention provides a method for indirectly assessing Eustachian tube function in a patient. The method may involve positioning an energy emitter in the nasopharynx adjacent a Eustachian tube; positioning an energy receiver adjacent the tympanic membrane via the external ear canal; directing energy from the emitter toward the receiver; generating an emitter signal representative of the energy from the emitter; generating a receiver signal representative of the energy received by the emitter; forming a comparison between the emitter signal and the receiver signal; and indirectly assessing function of the Eustachian tube during swallowing, using the comparison. 
     In one embodiment, the indirect assessing may involve estimating the physical characteristics of the Eustachian tube. 
     In another embodiment, the energy emitter may emit energy in the form of a pressure wave or electromagnetic energy. 
     In another aspect, the present invention provides a method for treating a Eustachian tube in a patient. The method may involve placing a guidewire into a Eustachian tube of the patient via the patient&#39;s nasopharynx; introducing a debulking device along the guidewire into the Eustachian tube of the patient; and removing edematous tissue including hypertropic mucosa from a surface along one side of the Eustachian tube. 
     In one embodiment, the guidewire may include markings and the method may also involve providing feedback related to the introducing into the Eustachian tube. 
     In another aspect, the present invention provides a method for treating a Eustachian tube in a patient. The method may involve introducing via the patient&#39;s nasopharynx a guidewire submucosally between cartilage and a mucosal surface of a Eustachian tube; introducing a debulking device along the guidewire into submucosal tissue of the Eustachian tube, between the cartilage and the mucosal surface; and removing some of the submucosal tissue. 
     In another aspect, the present invention provides a method for treating muscular dysfunction or an anatomical disorder of a Eustachian tube in a patient. The method may involve creating a lesion in at least one of a tensor villi palatine muscle or a levator villi palatine muscle to affect a stiffening of the muscle(s) upon resorption of the lesion. 
     In one embodiment, the stiffening may include a shortening or a tensioning of the tensor villi palatine or the levator villi palatine. 
     In another embodiment, the creating of a lesion may involve applying a therapy from the group including mechanical, laser, radio frequency and chemical therapies. 
     In another aspect, the present invention provides a method for treating a Eustachian tube in a patient. The method may involve placing a dual lumen pressure equalization tube through the tympanic membrane of the patient, the tube having a distal extension for location in a region of the Eustachian tube; providing a medication to the region of the Eustachian tube through a first lumen of the dual lumen tube in fluid communication with the distal extension; and providing ventilation across the tympanic membrane through a second lumen of the dual lumen tube. 
     In one embodiment, the medication may be configured to reduce edema in the Eustachian tube region. The medication can include a surfactant configured to modify a surface tension of a mucosal layer of the Eustachian tube to effect an enhanced wetting of the mucosal surface with the medication. 
     In one embodiment, the medication may include particles configured for capturing by mucosal tissue of the Eustachian tube to effect an extended release of the medication. 
     In one aspect, the present invention provides an apparatus for treating a Eustachian tube in a patient. The apparatus may include a dual lumen tube for insertion into a tympanic membrane of the patient&#39;s ear, the tube having: a distal extension for placement in a region of the Eustachian tube; a first lumen for providing a medication to the region of the Eustachian tube through the distal extension; and a second lumen for providing ventilation across the tympanic membrane. 
     In one embodiment, the first lumen may be disposed within the second lumen. In another aspect, the second lumen may be disposed within the first lumen. In yet another aspect, the first lumen may be disposed adjacent the second lumen. 
     In another embodiment, the dual lumen tube may be made from a biodegradable bioresorbable material. 
     In another aspect, the present invention provides a method for treating a Eustachian tube in a patient. The method may involve accessing a Eustachian tube region via the nasopharynx, using a guide having a lumen; introducing a guidewire through the lumen of the guide to position it submucosally between cartilage and a mucosal surface of the Eustachian tube; passing a temporary intraluminal implant having a drug delivery reservoir along the guidewire to position the implant submucosally in a posterior cushion of the Eustachian tube region between the lumen and the cartilage; and delivering a drug to the Eustachian tube region from the drug delivery reservoir. 
     In one embodiment, the method may also involve contemporaneously delivering a drug to adenoids and the Eustachian tube region from the drug delivery reservoir. 
     In one embodiment, the drug delivery reservoir may include a coating layer disposed on the implant. 
     In another embodiment, the guide may be made from a biodegradable bioresorbable material. 
     In another aspect, the present invention provides a method for treating a Eustachian tube in a patient. The method may involve obtaining access to a Eustachian tube region via the nasopharynx; introducing via the patient&#39;s nasopharynx a hollow guidewire dimensioned to reach into the Eustachian tube region, the hollow guidewire comprising a plurality of apertures disposed at or near its distal end; and delivering a drug to at least one of the Eustachian tube or a middle ear region of the patient&#39;s ear through the apertures. 
     In another aspect, the present invention provides a system for accessing a Eustachian tube of a patient. The system may include a guide configured for passing into a nasal passage of the patient to position a distal tip of the catheter at or near a Eustachian tube, the guide having distal tip with a bend having an angle between 30 and 90 degrees; and a guidewire configured to pass through the guide into the Eustachian tube. 
     In one embodiment, the guide may include a catheter. 
     In another embodiment, the guide may include a dual lumen tube. 
     In another embodiment, the system may also include a diagnostic device configured for passage through the guide. 
     In another embodiment, the system may also include a treatment device configured for passage through the guide. 
     In another aspect, the present invention provides a device for treating a Eustachian tube. The device may include an elongate rigid shaft. The device may also include an elongate and flexible insert coupled to the shaft, the insert including a therapeutic device for treating an elongate portion of a Eustachian tube, the insert including a lateral stiffness which deflects in accordance with the Eustachian tube, and a column stiffness which allows the insert to be pushed into the Eustachian tube without buckling. 
     In one embodiment, the elongate rigid shaft may include a distal end with a bend ranging from 30 to 90 degrees. 
     In one embodiment, the elongate rigid shaft may include a proximal end which may include at least one fluid fitting for supplying a fluid to the insert. 
     In one embodiment, the elongate rigid shaft may include a lumen for passage of a guidewire. 
     In one embodiment, the insert may include a flexible core wire. 
     In one embodiment, the flexible core wire may be constructed from a super-elastic alloy. 
     In one embodiment, the flexible core wire may include an atraumatic tip at a distal most portion of the insert. 
     In one embodiment, the therapeutic device may include a balloon. 
     In one embodiment, the balloon may include a microporous structure. 
     In one embodiment, the balloon may be expandable to a preformed shape which matches a profile of a Eustachian tube. 
     In one embodiment, the balloon may include a drug coating. 
     In one embodiment, the drug coating may be one of a steroid, antibiotic, antifungal, nonsteroidal anti-inflammatory, steroidal anti-inflammatory, surfactant, or anti-mucoidal substance. 
     In one embodiment, the therapeutic device may be detachable from the rigid shaft. 
     In one embodiment, the therapeutic device may include a lumen. 
     In one embodiment, the therapeutic device may be biodegradable and may include a therapeutic substance. 
     In one embodiment, the therapeutic substance may be one of a steroid, antibiotic, antifungal, nonsteroidal anti-inflammatory, steroidal anti-inflammatory, surfactant, or anti-mucoidal substance. 
     In one embodiment, the therapeutic device may include an expandable stent. 
     In one embodiment, the expandable stent may include a therapeutic substance. 
     In another aspect, the present invention provides a method for dilating a Eustachian tube of a patient. A guide catheter may be advanced through a nasal passage of the patient to position a distal end of the guide catheter at or near an opening of the Eustachian tube of the patient. A distal portion of the guide catheter may include a bend having an angle between 30 and 90 degrees. The distal portion may be more flexible than a proximal portion of the guide catheter. A guidewire may be advanced through the guide catheter such that a distal end of the guidewire enters the Eustachian tube. A dilation catheter may be advanced over the guidewire to position a dilator of the dilation catheter within the Eustachian tube. The dilator may be expanded to dilate the Eustachian tube. The dilation catheter and guidewire may be removed from the patient. 
     In one embodiment, the distal portion of the guide catheter may be malleable, and a bend in the distal portion may be formed by a user of the guide catheter. 
     In one embodiment, the opening of the Eustachian tube may include a pharyngeal ostium of the Eustachian tube, and the dilation catheter may be advanced to position the dilator in the pharyngeal ostium. 
     In one embodiment, the guidewire may be an illuminating guidewire. Light may be emitted from the illuminating guidewire, and the emitted light may be viewed. 
     In one embodiment, the emitted light may be viewed using an endoscope positioned in the patient&#39;s head. 
     In one embodiment, the guide catheter may be removed from the patient before advancing the dilation catheter over the guidewire. 
     In one embodiment, the dilation catheter may be advanced over the guidewire and through the guide catheter. The removing step may include removing the guide catheter from the patient. 
     In one embodiment, the dilation catheter may include a balloon dilation catheter, and expanding the dilator may include inflating a balloon of the balloon dilation catheter. 
     In one embodiment, inflating the balloon may expand a stent within the Eustachian tube. 
     In one embodiment, the dilation catheter may include lateral wings, and expanding the dilator may include using the lateral wings to maintain the position of the balloon. 
     In one embodiment, the balloon may be shaped when inflated to match a conical aperture of a pharyngeal ostium of the Eustachian tube ET, and expanding the dilator may include expanding the balloon within the pharyngeal ostium of the Eustachian tube ET. 
     In one embodiment, the balloon may be shaped to have a cross-section which does not occupy the entirety of the Eustachian tube, and expanding the dilator may include maintaining the balloon in position to relieve pressure within the Eustachian tube. 
     In one embodiment, the balloon may include cutting members, and expanding the dilator may include cutting the Eustachian tube wall with the cutting members. 
     In one embodiment, an endoscope may be advanced through the nasal passage, and the dilation catheter may be viewed using the endoscope. 
     In one embodiment, viewing the dilation catheter includes viewing a marker on a shaft of the catheter. A location of the dilator relative to the opening of the Eustachian tube may be approximated based on a distance of the marker from a proximal end of the dilator. 
     In one embodiment, at least one substance may be applied to the Eustachian tube using the dilator. 
     In one embodiment, the dilator may include a porous balloon for delivering the substance. 
     In one embodiment, the dilator may include a balloon with a plurality of needles for delivering the substance. 
     In one embodiment, the dilation catheter may apply a force against the Eustachian tube to maintain a position of the dilator during expanding. 
     In another aspect, the present invention provides a method for dilating a Eustachian tube of a patient. A guide catheter may be advanced through a nasal passage of the patient to position a distal end of the guide catheter at or near an opening of the Eustachian tube of the patient. A distal portion of the guide catheter may include a bend having an angle between 30 and 90 degrees. The distal portion may be more flexible than a proximal portion of the guide catheter. A delivery catheter may be advanced through the guide catheter to place the delivery catheter within the Eustachian tube. An elongate substance delivery device may be delivered into the Eustachian tube using the delivery catheter. The dilation catheter and guidewire may be removed from the patient while leaving the elongate drug delivery device in the Eustachian tube. 
     In one embodiment, the elongate substance delivery device may be an elongate string configured to elute at least one therapeutic substance. 
     In one embodiment, delivering the elongate substance delivery device may include internally detaching the elongate string from the delivery catheter. 
     In one embodiment, delivering the elongate substance delivery device may include externally detaching the elongate polymer string from the delivery catheter. 
     In one embodiment, the elongate substance delivery device may be a balloon configured to elute the substance over time. 
     In one embodiment, delivering the elongate drug deliver device may include inflating the balloon within the Eustachian tube and decoupling the balloon from the delivery catheter. 
     In one embodiment, the balloon may be configured to allow pressure equalization within the Eustachian tube. 
     In one embodiment, the elongate drug delivery device may be an expandable stent. 
     In one embodiment, delivering the elongate drug delivery device may include inserting the expandable stent into the Eustachian tube and unconstraining a proximal end of the expandable stent to allow the proximal end of the expandable stent to expand within the Eustachian tube. 
     In one embodiment, the elongate drug delivery device may be an elongate insert including an elongate central member connected to a plurality of braces, and each brace may be connected to an elongate outer member. 
     In one embodiment, the braces may provide and maintain open spaces in the Eustachian tube to maintain pressure equalization therein. 
     In another aspect, a method for dilating an Eustachian tube of a patient may involve: advancing a dilation device through a nasal passage of the patient to position a dilator of the device at least partially in a Eustachian tube of the patient; expanding the dilator to dilate a portion of the Eustachian tube; collapsing the dilator; and removing the dilation device from the patient, wherein the dilated portion of the Eustachian tube remains at least partially dilated after removal of the device. In one embodiment, a distal portion of the dilation device may be malleable, and the method may further involve forming, by a user of the dilation device, a bend in the distal portion. In this embodiment or an alternative embodiment, the distal portion of the dilation device may include a bend of between about 30 degrees and about 90 degrees. In some embodiments, the opening of the Eustachian tube is a pharyngeal ostium of the Eustachian tube, and the dilation device is advanced to position the dilator in the pharyngeal ostium. 
     In one embodiment, the dilation device may include a guide portion slidably coupled with the dilator. In such an embodiment, advancing the dilation device may involve advancing the dilation device into the nasal cavity to position a distal end of the device at or near the opening of the Eustachian tube and advancing the dilator relative to the guide portion to position the dilator in the opening. In one embodiment, the guide portion may include an outer tube and an inner shaft extending distally beyond the outer tube, and the dilator may be advanced through the tube and over the inner shaft. In one embodiment, the inner shaft may be malleable, and the method further include forming, by a user of the dilation device, a bend in the inner shaft. 
     In some embodiments, the dilator may be a balloon, and expanding the dilator may involve inflating the balloon. In one embodiment, inflating the balloon may expand a stent within the Eustachian tube. In one embodiment, the balloon may include cutting members, and expanding the dilator may further involve cutting the Eustachian tube wall with the cutting members. 
     Optionally, the method may further include advancing an endoscope through the nasal passage and viewing at least one of the advancing, expanding, collapsing or removing steps using the endoscope. In one embodiment, viewing may include viewing a marker on the dilation device. In this embodiment, the method may further include approximating a location of the dilator relative to the opening of the Eustachian tube based on a distance of the marker from a proximal end of the dilator. 
     In one embodiment, the method may further comprise applying at least one substance to the Eustachian tube using the dilator. In one embodiment, the dilator may be a porous balloon for delivering the substance. In another embodiment, the dilator may be a balloon with a plurality of needles for delivering the substance. 
     In another aspect, a device for dilating an Eustachian tube of a patient may include a handle, a guide member coupled with the handle, a dilator slidably coupled with the handle and disposed over at least part of the guide member, an actuator on the handle for advancing the dilator along the guide member, and an expansion member coupled with the handle for allowing expansion of the dilator. In one embodiment, the dilator may comprise a balloon catheter including an inflatable balloon, and the expansion member may comprise an inflation port in fluid communication with an inflation lumen of the balloon catheter. In one embodiment, the balloon may include multiple apertures through which one or more drugs may be passed to contact the Eustachian tube. In this or another embodiment, the balloon may include at least one cutting member for cutting tissue within the Eustachian tube upon expansion. 
     In some embodiments, the guide member may comprise a shaft over which the dilator slides. In some embodiments, the shaft is malleable. In this or other embodiments, the shaft may have a bend with an angle of between about 30 degrees and about 90 degrees. In some embodiments, a distal end of the shaft may have a ball tip. 
     In some embodiments, the advancement member comprises a slide. In some embodiments, the dilator may comprise a rigid proximal portion and a flexible distal portion. In one embodiment, the rigid proximal portion may comprise a hypotube. In one embodiment, the guide member may comprise a tubular shaft through which the dilator slides. In one embodiment, this shaft may be malleable. Additionally or alternatively, the shaft may have a bend with an angle of between about 30 degrees and about 90 degrees. 
     Optionally, the device may further include a suction port disposed on the handle and in fluid communication with a suction lumen passing through the guide member or the dilator. Also optionally, the device may further include an endoscope connection member for coupling an endoscope with the device. 
     For a further understanding of the nature and advantages of the invention, reference should be made to the following description taken in conjunction with the accompanying figures. Each of the figures is provided for the purpose of illustration and description only and is not intended to limit the scope of the embodiments of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-section of a human ear showing the inner, middle and outer ear portions and the Eustachian tube connecting the middle ear with the nasopharynx region of the throat via a distal opening thereof. 
         FIG. 2  is a cross-section of a human head showing the nasopharynx region of the throat illustrated in  FIG. 1  containing the distal opening of the Eustachian tube illustrated in  FIG. 1 . 
         FIG. 3  is a cross-section of a human ear in the orientation shown in  FIG. 1  showing a prior art surgical method for relieving fluid in the middle ear in which a ventilation tube is placed within an incision in the eardrum. 
         FIG. 4  is a cross-section of a human ear in the orientation shown in  FIG. 1  showing a prior art surgical method for relieving fluid in the middle ear in which a syringe is shown having a needle perforating the eardrum. 
         FIGS. 5-6  show a cross-section of a human head in the orientation shown in  FIG. 2  showing a prior art politzerization method for relieving fluid in the middle ear in which a syringe is shown having a flexible tip extending into the nose and/or throat area so that the tip abuts the pharyngeal ostium of the Eustachian tube while the nose is plugged. 
         FIG. 7  shows a cross-sectional view of a human head showing the nasopharynx region and a guide catheter in the nasal passage where the distal tip of the guide catheter is adjacent the Eustachian tube opening. 
         FIG. 8  shows a section of the anatomical region around a Eustachian tube (ET). 
         FIG. 9  shows a section of the anatomical region around a Eustachian tube showing a diagnostic or therapeutic procedure to debulk edematous tissue around the ET. 
         FIG. 10  shows a section of the anatomical region around a Eustachian tube showing an alternative therapeutic procedure to debulk edematous tissue around the ET. 
         FIG. 11  shows an exemplary drug delivery system for delivering a pharmaceutical agent to treat ET inflammation or edema. 
         FIG. 12  shows an alternative drug delivery system for delivering a pharmaceutical agent to treat ET inflammation or edema that may be provided through the nasopharynx. 
         FIG. 13  shows a section of the anatomical region around the ET showing a diagnostic or therapeutic procedure being performed by devices inserted through the pharyngeal ostium of the Eustachian tube. 
         FIG. 13A  shows an enlarged view of the region encircled by a broken line in  FIG. 13 . 
         FIG. 13B  shows a front view of a human head with a portion of the face removed to show an embodiment of a method of introducing a guidewire into a Eustachian tube. 
         FIGS. 14A-14D  illustrate various examples of working elements that could be located on the diagnostic or therapeutic device in  FIG. 13 . 
         FIGS. 15A and 15B  show side views of example devices for providing a therapy to a Eustachian tube. 
         FIGS. 15C-15E  show cross-sectional views of example devices providing therapies to a Eustachian tube. 
         FIG. 15F  shows a side elevational view of a dilation device for providing therapy to a Eustachian tube. 
         FIGS. 16A and 16B  show a partial cross-section of devices being used in a method for treating a Eustachian tube of a patient. 
         FIG. 17A  shows a frontal view of an illuminated guidewire for treating a Eustachian tube in use in a patient. 
         FIGS. 18A and 18B  show a partial cross-section of a device being used in a method for treating a Eustachian tube of a patient. 
         FIG. 18C  shows a partial cross-section of a device being used in a method for treating a Eustachian tube of a patient. 
         FIG. 18D  shows a partial cross-section of a device being used in a method for treating a Eustachian tube of a patient. 
         FIGS. 18E  shows a side view of a dilator for providing therapy to a Eustachian tube of a patient. 
         FIG. 18F  shows a perspective view of the dilator of  FIG. 18E . 
         FIG. 18G  shows a cross-sectional view of the dilator of  FIG. 18E  within the Eustachian tube of a patient, with the dilator in an expanded state. 
         FIG. 18H  shows a side view of a dilator for providing therapy to a Eustachian tube of a patient. 
         FIG. 18I  shows a perspective view of a dilator for providing therapy to a Eustachian tube of a patient. 
         FIG. 18J  shows a cross-sectional view of the dilator of  FIG. 18I  within the Eustachian tube of a patient, with the dilator in an expanded state. 
         FIG. 18K  shows a side view of a dilator for providing therapy to a Eustachian tube of a patient. 
         FIG. 18L  shows a perspective view of the dilator of  FIG. 18K . 
         FIG. 18M  shows a side view of a dilator for providing therapy to a Eustachian tube of a patient. 
         FIG. 18N  shows a perspective view of the dilator of  FIG. 18M   
         FIG. 18O  shows a side view of a dilator for providing therapy to a Eustachian tube of a patient. 
         FIG. 18P  shows a perspective view of the dilator of  FIG. 18O   
         FIG. 18Q  shows a side view of a dilator for providing therapy to a Eustachian tube of a patient. 
         FIG. 18R  shows a perspective view of the dilator of  FIG. 18Q   
         FIG. 18S  shows a side view of a dilator for providing therapy to a Eustachian tube of a patient, disposed within a Eustachian tube of a patient. 
         FIG. 18T  shows a cross-sectional view of the dilator of  FIG. 18S  within the Eustachian tube of a patient, with the dilator in an expanded state. 
         FIG. 18U  shows a side view of a dilator for providing therapy to a Eustachian tube of a patient, disposed in a Eustachian tube of a patient, with the dilator in a deflated state. 
         FIG. 18V  shows a side view of the dilator of  FIG. 18U  disposed in the Eustachian tube of a patient, with the dilator in a semi-inflated state. 
         FIG. 18W  shows a side view of the dilator of  FIG. 18U  disposed in the Eustachian tube of a patient, with the dilator in a fully inflated state. 
         FIG. 18X  shows a side view of a dilator for providing therapy to a Eustachian tube of a patient. 
         FIG. 18Y and 18Z  show before and after cross-sectional views of a Eustachian tube, respectively, that was treated by the dilator of  FIG. 18X . 
         FIGS. 19A and 19B  show side views of a stents for providing therapy to a Eustachian tube of a patient. 
         FIGS. 19C and 19D  show side views of a stent in different stages of expansion for providing therapy to a Eustachian tube of a patient. 
         FIGS. 20A, 20B and 20C  show cross-sectional views of distal tips of guide catheters for interfacing with the opening of a Eustachian tube of a patient. 
         FIGS. 21A and 21B  show perspective and cross-sectional views, respectively, of an elongate insert for providing therapy to a Eustachian tube of a patient. 
         FIG. 22A  shows a side view of a string insert for providing therapy to a Eustachian tube of a patient. 
         FIGS. 22B, 22C and 22D  show partial cross-sectional views of delivery catheters for delivering the string insert of  FIG. 22A . 
         FIGS. 22E and 22F  show partial cross-sectional views of the string insert of  FIG. 22A  being used in a method for providing therapy to a Eustachian tube of a patient. 
         FIGS. 23A-23C  are various views of two embodiments of a Eustachian tube access guide device coupled with an endoscope. 
         FIGS. 24A-24C  are various views of two embodiments of a Eustachian tube balloon dilation catheter coupled with an endoscope. 
         FIG. 25  is a side view of a Eustachian tube access guide according to one embodiment. 
         FIG. 26  is a side view of a Eustachian tube balloon dilation catheter according to one embodiment. 
         FIG. 27  is a side view of a Eustachian tube access guide and balloon dilation catheter disposed within the guide according to one embodiment. 
         FIGS. 28A-28D  are side views of a balloon catheter and a pre-shaped, curved stylet that curves the balloon catheter according to one embodiment. 
         FIGS. 29A and 29B  are side views of an extendable, telescoping balloon catheter with guide according to one embodiment. 
         FIG. 30  shows a side elevational view of are exemplary illuminating guidewire suitable for use with a balloon dilation catheter. 
         FIG. 31  shows a side cross-sectional view of the illuminating guidewire of  FIG. 30 . 
         FIG. 32  shows a side elevation view of an exemplary illuminating guidewire suitable for use with a balloon dilation catheter with a widened distal tip. 
         FIG. 33  shows a side cross-sectional view of the illuminating guidewire of  FIG. 32 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The embodiments of the present invention are directed toward methods and systems for accessing, diagnosing and treating target tissue regions within the middle ear and the Eustachian tube. 
     Access 
     One embodiment of the present invention is directed toward using minimally invasive techniques to gain trans-Eustachian tube access to the middle ear. In one embodiment, a middle ear space may be accessed via a Eustachian tube (ET). To obtain this access to the Eustachian tube orifice, a guide catheter having a bend on its distal tip greater than about 30 degrees and less than about 90 degrees may be used. Once accessed, diagnostic or interventional devices may be introduced into the Eustachian tube. Optionally, to prevent damage to the delicate middle ear structures, a safety mechanism may be employed. In one embodiment, the safety mechanism may include a probe and/or a sensor introduced into the middle ear via the tympanic membrane as shown in  FIG. 7 . For example, the probe may be an endoscope, and the sensor may be an electromagnetic transducer. 
       FIG. 7  is a cross-sectional view showing the nasopharynx region and a guide catheter  100  in the nasal passage where the distal tip  102  of the guide catheter  100  is adjacent the Eustachian tube opening.  FIG. 7  shows the guide catheter  100  having a bend on its distal tip  102  that is greater than about 30 degrees and less than about 90 degrees located adjacent the Eustachian tube orifice. A sensor  104  located adjacent the tympanic membrane may be used to monitor advancement of the guide catheter  100 . The sensor  104  is one example of a safety mechanism. 
     In various alternative embodiments, the guide catheter  100  may have any suitable length, diameter, angle of bend, and location of the bend along the length of the catheter  100 , to facilitate accessing a Eustachian tube opening. In some embodiments, for example, the guide catheter  100  may have a length between about 10 cm and about 20 cm, and more preferably between about 12 cm and about 16 cm. In various embodiments, the guide catheter  100  may have a bend with an angle between about 0 degrees and about 180 degrees, and more preferably between about 30 degrees and about 90 degrees. In one embodiment, for example, the guide catheter  100  may have a length, bend angle and overall configuration to access a Eustachian tube via entry through the nostril on the same side of the head as the Eustachian tube being accessed. In an alternative embodiment, the guide catheter  100  may have a length, bend angle and overall configuration to access a Eustachian tube via entry through a nostril on the opposite (contralateral) side of the head as the Eustachian tube being accessed. The bend angle of this latter embodiment, for example, may be larger than the bend angle of the guide catheter  100  used for same-side access. 
     In one embodiment, the guide catheter  100  may be malleable, so that a user may bend the guide catheter  100  to a desired shape that at least partially maintain itself during use. In another embodiment, the guide catheter  100  may be steerable. For example, at least a portion of the guide catheter  100  may be partially flexible, and that portion may be steered by a steering mechanism coupled with a proximal end of the catheter  100 , such as one or more pull wires or the like. Various embodiments may include one steerable portion or multiple steerable portions. Various embodiments may also include any suitable angle of steerability. For example, one steerable portion may be bendable to an angle of about 30 degrees, and another steerable portion may be bendable to an angle of about 45 degrees. Any combination of angles and steerable portions may be included in various embodiments. 
     In some embodiments, the guide catheter  100  may be combined with, or be capable of combining with, a flexible or rigid endoscope. In one embodiment, for example, a flexible endoscope may be built in to the body of the guide catheter  100 . In another embodiment, the guide catheter  100  may include an endoscope lumen through which a flexible endoscope may be advanced. In yet another embodiment, the guide catheter may include a lumen, clip or other attachment member (or members) for attaching to a rigid endoscope. For example, in some embodiments the guide catheter  100  may be attached to a variable degree of view rigid endoscope such as a swing prism endoscope. 
     Some embodiments of the guide catheter  100  may include an optional suction port on or near the proximal end, so that catheter  100  may be connected to a vacuum/suction source. In these embodiments, the guide catheter  100  may include a separate suction lumen, or alternatively, suction may be directed through the same lumen that devices are passed. Some embodiments may include a one-way valve for allowing passage of devices through the guide catheter  100  while maintaining suction pressure. 
     In use, the guide catheter  100  may be advanced into a nostril and through a nasal cavity to position a distal end of the catheter  100  at, in or near an opening into the Eustachian tube. In one embodiment, the guide catheter  100  may be passed through a nostril to the Eustachian tube on the ipsilateral (same side) of the head. In an alternative embodiment, the guide catheter  100  may be passed through a nostril to the Eustachian tube on the contralateral (opposite side) of the head. Once access to a Eustachian tube is achieved using the guide catheter  100 , any of a number of procedures may be performed on the Eustachian tube using any of a number of different devices. Optionally, in some embodiments, the guide catheter  100  may be used to suction out blood and/or other fluids/substances from the Eustachian tube and/or nasal cavity during and/or after advancement of the catheter  100 . In alternative embodiments described more fully below, the guide catheter  100  may be eliminated from the procedure, and the Eustachian tube may be accessing and treated with one or more devices without using the catheter  100 . 
     Diagnosis 
     Another embodiment of the present invention is directed to diagnosis of the condition of the middle ear and its structure. In one embodiment, diagnosis may include use of an endoscope that has been advanced into position through the guide catheter  100  or that is integrated into the guide catheter  100 . The design of the endoscope will allow for a 90 degree or more Y axis visualization and a 360 degree rotation. Such an endoscope may be used for assessment of cholesteotomas, ossicle function and/or condition, and the surgical follow-up. An exemplary endoscope that may be adapted as described above may use the IntroSpicio 115 1.8 mm camera developed by Medigus. Such a camera measures approximately 1.8 mm.times.1.8 mm and its small rigid portion allows for the maximum flexibility at the endoscope tip. 
     Alternatively, ultrasound may be used by injecting a fluid into the middle ear space and the ET and scanning the middle ear and the ET and its structure ultrasonically. Post-procedure the fluid may be aspirated or left to drain through the Eustachian tube. An ultrasound tipped catheter may be advanced up the ET to a position at the middle ear cavity. The ultrasound catheter may then be pulled down the ET and the physician may use an external video monitor to view the structure in and adjacent the ET. 
     Functional diagnosis of the Eustachian tube may be achieved via direct or indirect assessment. In one embodiment, for direct assessment, the diagnostic system may allow for the dynamic monitoring of the Eustachian tube during swallowing via a diagnostic probe inserted via the nasopharynx. Since such a diagnostic system may be used dynamically during swallowing, the probe may be made of a flexible and durable material configured to be atraumatic. In one embodiment, the guide catheter(s)  100  used in the nasopharynx approach may be removed once the diagnostic probe is in or near the ET region and prior to the swallowing. 
     In one embodiment, the diagnostic probe may comprise an endoscope to visualize the ET structure and function. Alternatively, the diagnostic probe may include a pressure transducer located on a catheter or a wire. When a pressure transducer is used, the pressure within the ET may be monitored during swallowing and the pressure measurements may be interpreted for ET opening function. Alternatively, an ultrasound probe may be inserted in the ET lumen to scan the ET region&#39;s structure. Fluid may be introduced into the ET to facilitate ultrasound diagnosis. For any of the above diagnostic systems, a single short length transducer that is repositioned after each swallow may be used. Alternatively, an array of transducers may be used to facilitate mapping of all or a portion of an ET. 
     The techniques described above may be used to directly access and diagnose a Eustachian tube of a patient. In one embodiment, a method for accessing a Eustachian tube of a patient may include inserting a guide catheter into a nasal passage of the patient, the guide catheter having a distal tip with a bend having an angle between about 30 and about 90 degrees; and advancing the guide catheter in the nasal passage toward an opening of the Eustachian tube in the nasopharynx to place the distal tip adjacent the Eustachian tube opening. Additionally, the method may also include advancing a diagnostic device through the guide catheter to place a distal tip of the diagnostic device adjacent the Eustachian tube opening. The diagnostic device may include a diagnostic catheter. The diagnostic device may include an endoscope, a pressure transducer, or an ultrasound catheter. 
     Additionally, the method may also include introducing a diagnostic probe into the Eustachian tube to directly assess Eustachian tube function. It is preferred that the diagnostic probe is made from a flexible and Eustachian tube compatible material. Alternatively, the diagnostic probe may comprise a pressure transducer located on a guidewire, and whereby the method also includes monitoring pressure within the Eustachian tube while the patient is swallowing; and assessing an opening function of the patient&#39;s Eustachian tube using the monitoring. The method may also include removing the guide catheter after the diagnostic probe is placed into the Eustachian tube. Additionally, or alternatively, the diagnostic probe may comprise an ultrasound probe. 
     For indirect functional diagnosis of a Eustachian tube, in some embodiments, an external energy source may be used to assess opening of the Eustachian tube. For example, possible energy sources may include, but are not limited to, pressure, sound, light or other electromagnetic energy. In one embodiment of indirect assessment, an emitter may be positioned in the nasopharynx and a receiver may be placed at the tympanic membrane. Correlation between the emitted signal and the received signal may be translated into the physical characteristics of the ET during swallowing. 
     The techniques described above may be used to implement procedures for indirectly accessing and diagnosing the Eustachian tube of a patient. The indirect assessment method includes positioning an energy emitter in the nasopharynx adjacent a Eustachian tube; positioning an energy receiver adjacent the tympanic membrane via the external ear canal; directing energy from the emitter toward the receiver; generating an emitter signal representative of the energy from the emitter; generating a receiver signal representative of the energy received by the emitter; forming a comparison between the emitter signal and the receiver signal; and indirectly assessing function of the Eustachian tube during swallowing, using the comparison. The energy emitter can be a device that emits energy in the form of a pressure wave or electromagnetic energy. The indirect assessment may also include estimating the physical characteristics of Eustachian tube. 
     Treatment 
     Another embodiment of the present invention is directed toward the treatment of Eustachian tube disorders. In some cases, for example, Eustachian tube disorders may be related to structural obstructions of the Eustachian tube. Structural disorders of the Eustachian tube are often the result of anatomical abnormalities or excessive or edematous tissue in or around the Eustachian tube, as shown in  FIG. 8 .  FIG. 8  shows a section of the anatomical region around a Eustachian tube ET.  FIG. 8  shows some general anatomical landmarks including the tympanic membrane TM, the carotid artery, the ET cartilage as well as the location of the tensor villi palatine and the levator villi palatine muscles.  FIGS. 9-10  show diagnostic or therapeutic procedures being performed in the region around the ET. 
       FIG. 9  shows a section of the anatomical region around a Eustachian tube showing a diagnostic or therapeutic procedure to debulk edematous tissue around the ET. The procedure illustrated in  FIG. 9  includes accessing the ET lumen using a guidewire  202  and removing tissue from one side of the ET using a debulking tool  204 . As shown in  FIG. 9 , in one embodiment, the debulking tool  204  may have a retractable debulking tip  206  projecting from one side so that the tip removes tissue from one side of the ET lumen. This therapeutic procedure preferably allows for controlled access and positioning within the ET and prevents injury to opposing surfaces. It should be realized that the above-described therapeutic procedures can be performed with the aid of ultrasound guidance or visualization, for example, by using an intra-ET visualization catheter. The ultrasound can be used for diagnosis before therapy as described above. It may also be used for guidance and or assistance during the therapy. In alternative embodiments, the debulking tool  204  may be advanced into a Eustachian tube without using a guidewire and may be advanced either with or without using a guide catheter. 
       FIG. 10  shows a section of the anatomical region around a Eustachian tube showing an alternative therapeutic procedure to debulk edematous tissue around the ET. In the alternative procedure shown in  FIG. 10 , the debulking device  304  may be introduced at its tip or distal end  306  submucosally between cartilage  330  and the mucosal surface, so that the mucosal surface is preserved. For this alternative procedure, the guidewire  302  and/or the debulking device may be tracked between the lumen and the cartilage, thereby protecting both the mucosal surface and the carotid artery. As shown in  FIG. 10 , the guidewire  302  may be inserted at a submucosal entry point between the ET cartilage and the mucosal surface. Subsequently, the debulking tool  304  may be introduced along the guidewire  302  to debulk the tissue region without affecting the mucosal surface. Ultrasound, like low power, high efficiency ultrasounds, can be used as the debulking tool to ablate, shrink or debulk tissues under the mucosal tissue. As with the device described previously, in alternative embodiments, the debulking device  304  may be advanced into a Eustachian tube without using a guidewire and may be advanced either with or without using a guide catheter. 
     The treatment techniques described above may be used to treat the Eustachian tube of a patient by placing a guidewire into a Eustachian tube of the patient via the patient&#39;s nasopharynx; introducing a debulking device along the guidewire into the Eustachian tube of the patient; and removing edematous tissue including hypertropic mucosa from a surface along one side of the Eustachian tube. The guidewire may include markings for providing feedback related to the introducing into the Eustachian tube. Alternatively, the debulking tool can be introduced into the ET without first placing a guidewire therein. In either case (i.e., with or without a guidewire), in some embodiments the treatment devices may be advanced into the Eustachian tube via a guide catheter, while in alternative embodiments the treatment device may be advanced without use of a guide catheter. In fact, any of the treatment devices described herein may be used with or without a guidewire and with or without a guide catheter, in various alternative embodiments of the devices. 
     Alternatively, a method for treating a Eustachian tube in a patient may include introducing via the patient&#39;s nasopharynx a guidewire submucosally between cartilage and a mucosal surface of a Eustachian tube; introducing a debulking device along the guidewire into submucosal tissue of the Eustachian tube, between the cartilage and the mucosal surface; and removing some of the submucosal tissue. 
     In addition to the therapeutic procedures described above and illustrated in  FIGS. 9-10 , tissue removal or remodeling (e.g. shrinkage) may be accomplished using mechanical, laser, radio frequency, and/or chemical therapies. For example, in cases where muscular dysfunction or anatomical disorder is a contributing factor, the muscles (tensor villi palatine or levator villi palatine) may be shortened or tensioned. One method of accomplishing or shortening the muscles is to create a lesion in the muscles. Over time the lesion is absorbed and the muscle tightens due to the resorbed muscular mass in a manner similar to somnoplasty. 
     Another embodiment of the present invention is directed toward the treatment of Eustachian tube disorders caused by inflammation or edema. In addition to the surgical procedures described above, edema may also be reduced through pharmaceutical therapy. Delivery of therapeutic agents, especially steroids, into the ET mucosa may be facilitated locally using a range of methods including aspirating directly into the ET using a micro-catheter designed to enter either the nasopharynx or the middle ear side of the ET. Alternatively, an agent may be delivered from the surface of a dilation balloon. In this case, the agent may be deposited into the mucosal layer rather than onto its surface. Sustained delivery may be facilitated by depositing the drug into a reservoir and embedding the reservoir into the mucosa. Extending the residence time of therapeutic agents may be achieved by including the agents as particles and charging the reservoir particles such that they adhere to the mucosa surface. Alternatively, the residence time of therapeutic agents may be controlled by implanting the reservoir into the ET or its substructure. 
     An exemplary drug delivery system according to one embodiment is shown in  FIG. 11 . As shown in  FIG. 11 , a pressure equalization tube  400  may be inserted into the tympanic membrane. The pressure equalization tube includes an extension  402  that resides in the region of the Eustachian tube, where the extension has drug delivery capabilities. As shown on  FIG. 11 , the pressure equalization tube  400  may be dual-lumen to provide drug delivery and ventilation functions. The pressure equalization tube  400  having an extension  402  may be designed to slide between the radial fibers of the tympanic membrane TM. When in place the tube may be oriented to minimize migration paths. 
     Alternatively, a drug delivery system may be provided through the nasopharynx as illustrated in  FIG. 12 . As shown in  FIG. 12 , the drug delivery may be provided from an intraluminal temporary implant  500 . The temporary nature of the implant  500  may require a removal system or may provide for natural removal through degradation and/or digestion. Similar to the debulking devices described above, the drug delivery system may also be implanted submucosally, thus having the benefit of not obstructing the surface mucosa. In one embodiment, the implant may be deployed into the posterior cushion of the ET between the lumen and the cartilage. This method may benefit from the use of consistent anatomical landmarks and may minimize the likelihood of trauma to the middle ear or carotid artery. The implant  500  may include an anchored drug delivery reservoir in the form of a coil having a reducing diameter distal  502  to proximal  504 , respectively. 
       FIG. 13  shows a section of the anatomical region around a Eustachian tube ET showing a diagnostic or therapeutic procedure being performed by devices inserted through the pharyngeal ostium of the Eustachian tube.  FIG. 13  shows a guidewire GW inserted into a desired region in the ET through the nasopharynx and a diagnostic or therapeutic procedure being performed by a device introduced into the Eustachian tube over guidewire GW. 
       FIG. 13A  shows an enlarged view of region  33 A in  FIG. 13 , showing the anatomical region around a Eustachian tube ET, and showing a diagnostic or therapeutic procedure being performed by devices inserted through the pharyngeal ostium of the Eustachian tube. In one embodiment, guidewire GW comprises an anchoring balloon  3200  located on the distal region of guidewire GW. Anchoring balloon  3200  is inflated after positioning guidewire GW at a target location. Anchoring balloon  3200  anchors guidewire GW to the adjacent anatomy and prevents accidental repositioning of guidewire GW during a diagnostic or therapeutic procedure. Anchoring balloon  3200  may be made from any suitable compliant or semi-compliant material, such as but not limited to crosslinked polyethylene or other polyolefins, polyurethane, flexible polyvinylchloride, Nylon, or the like. In various alternative embodiments, guidewire GW may include one or more anchoring elements other than anchoring balloon  3200 , such as a notch on guidewire GW, a bent region on guidewire GW, a self-expanding element, a hook, a coiled element, or the like. In another embodiment, guidewire GW may include a sensor  3202  located on the distal region of guidewire GW. Sensor  3202  may enable guidewire GW to be used in conjunction with a suitable surgical navigation system. In one embodiment, sensor  3202  may include an electromagnetic sensor used in conjunction with an electromagnetic surgical navigation system such as GE InstaTrakTM3  500  plus system. One or more sensor  3202  or other types of surgical navigation sensors or transmitters may also be located on other diagnostic or therapeutic devices disclosed herein. Sensor  3202  may be used in conjunction with a stationary sensor  3204  located in the external ear. The combination of sensor  3202  and stationary sensor  3204  may facilitate positioning of guidewire GW in a target region. 
     In some embodiments, the guidewire GW may include one or more stop members (not pictured), either at its distal end, its proximal end, or both. Such stop members may be in addition to the anchoring balloon  3200  or may be included in embodiments that do not have an anchoring balloon  3200 . The stop members help prevent the distal end of guidewire GW from being passed too far into the Eustachian tube and thus help prevent any damage to structures that might result from advancing guidewire GW too far. In one embodiment, for example, guidewire GW may include a distal curve or bend that prevents it from passing through a narrow portion of the Eustachian tube. This or another embodiment may also include a proximal stop member that abuts against a proximal portion of a guide catheter through which to the guidewire is passed, thus preventing it from passing too far. In any of the above described embodiments, the guidewire may also have an atraumatic tip. 
     In another embodiment, a radiopaque plug  3206  may be inserted from the external ear to a region adjacent to an eardrum. Radiopaque plug  3206  may serve as a fiducial marker during preoperative scanning of the patient and thus may enable a physician to accurately position a diagnostic or therapeutic device close to the eardrum. Other image guidance methods and devices may also be used in conjunction with diagnostic or therapeutic procedures disclosed herein.  FIG. 13A  also shows a diagnostic or therapeutic device  3208  comprising a shaft  3210  and a working element  3212 , e.g. a dilating balloon being introduced over guidewire GW. Diagnostic or therapeutic device  3208  may comprise a radiopaque marker  3214 . 
       FIG. 13B  shows a front view of a human head with a portion of the face removed to show an embodiment of a method of introducing a guidewire GW into a Eustachian tube. In  FIG. 13B , a guide catheter  3250  is introduced through a nostril into the nasopharynx. A distal portion of guide catheter  3250  may comprise a bent or angled region. For example, in one embodiment such bent or angled region may form an internal angle ranging from about 45 degrees to about 150 degrees. Guide catheter  3250  may be constructed using one of the various designs disclosed in the assignee&#39;s copending patent application Ser. No. 11/926,565 (Attorney Docket No. 83529.0066), which is hereby incorporated herein by reference. Guide catheter  3250  is positioned in the nasopharynx such that the distal tip of guide catheter  3250  is located near a nasopharyngeal opening of a Eustachian tube. Thereafter, a guidewire GW is introduced through guide catheter  3250  into the Eustachian tube. Guidewire GW can then be used to advance one or more diagnostic or therapeutic devices into the Eustachian tube to perform one or more diagnostic or therapeutic procedures. 
       FIGS. 14A-14D  illustrate various embodiments of working elements that may be located on a diagnostic or therapeutic device such as a catheter  3210 , which may in some embodiments be advanced over a guidewire  3208 .  FIG. 14A  shows a balloon dilation catheter  3210  having a working element comprising a dilating balloon  3312 , advanced over a guidewire  3208 . The dilating balloon  3312  may be made from a suitable non-compliant material, such as but not limited to polyethylene terephthalate, Nylon, or the like. In various alternative embodiments, the balloon catheter  3210  may be advanced over the guidewire  3208  without the use of a guide catheter, over or through a guide catheter without the use of the guidewire  3208 , over the guidewire  3208  and through a guide catheter, or by itself without using the guidewire  3208  or guide catheter (such as with a partially rigid balloon catheter). Also in various embodiments, the balloon catheter  3210  may include multiple lumens for inflation/deflation of the balloon  3312 , irrigation and/or suction, drug delivery, passage of a visualization device such as a flexible endoscope, or any suitable combination thereof. 
       FIG. 14B  shows an example of a working element comprising a dilating balloon  3314  loaded with a balloon-expandable stent  3316 . In some embodiments, dilating balloon  3314  may be made from a suitable non-compliant material, such as but not limited to polyethylene terephthalate, Nylon, or the like. Several types of stent designs may be used to construct stent  3316 , such as but not limited to metallic tube designs, polymeric tube designs, chain-linked designs, spiral designs, rolled sheet designs, single wire designs, or the like. These designs may have an open-cell or closed-cell structure. A variety of fabrication methods may be used for fabricating stent  3316 , including but not limited to laser cutting a metal or polymer element, welding metal elements, etc. A variety of materials may be used for fabricating stent  3316 , including but not limited to metals, polymers, foam type materials, plastically deformable materials, super elastic materials, and the like. A variety of features may be added to stent  3316 , including but not limited to radiopaque coatings, drug elution mechanisms to elute anti-inflammatory agents, antibiotics, and the like. In one embodiment, stent  3316  may be bioabsorbable. Working elements may also comprise a self-expanding stent instead of a pressure-expandable stent. 
       FIG. 14C  shows an alternative embodiment comprising a lavage catheter  3210  with a working element comprising a lavage element  3318 . Lavage element  3318  may include multiple lavage openings  3320 . Lavage openings  3320  may be connected to a lavage lumen in the shaft of the catheter  3210 , through which suitable lavage media such as solutions containing contrast agents, pharmaceutically acceptable salt or dosage form of an antimicrobial agent (e.g. antibiotic, antiviral, anti-parasitic, antifungal, etc.), an anesthetic agent with or without a vasoconstriction agent (e.g. Xylocaine with or without epinephrine, Tetracaine with or without epinephrine, etc.), an analgesic agent, a corticosteroid or other anti-inflammatory (e.g. an NSAID), a decongestant (e.g. vasoconstrictor), a mucus thinning agent (e.g. an expectorant or mucolytic), an agent that prevents or modifies an allergic response (e.g. an antihistamine, cytokine inhibitor, leucotriene inhibitor, IgE inhibitor, immunomodulator), an allergen or another substance that causes secretion of mucous by tissues, hemostatic agents to stop bleeding, antiproliferative agents, cytotoxic agents (e.g. alcohol), biological agents such as protein molecules, stem cells, genes or gene therapy preparations, or the like may be delivered. In one embodiment, a fraction of lavage openings  3320  may be connected to an aspiration lumen to aspirate the lavage media out of the Eustachian tube. 
       FIG. 14D  shows an example of a working element comprising a substance delivery reservoir  3322 . Substance delivery reservoir  3322  may be fully or partially biodegradable or non-biodegradable. In one embodiment, substance delivery reservoir  3322  is made of a suitable biocompatible material such as hydrogel (e.g. collage hydrogel). In another embodiment, substance delivery reservoir  3322  comprises a porous matrix formed of a porous material such as a flexible or rigid polymer foam, cotton wadding, gauze, etc. Examples of biodegradable polymers that may be foamed or otherwise rendered porous include polyglycolide, poly-L-lactide, poly-Dlactide, poly(amino acids), polydioxanone, polycaprolactone, polygluconate, polylactic acid-polyethylene oxide copolymers, modified cellulose, collagen, polyorlhoesters, polyhydroxybutyrate, polyanhydride, polyphosphoester, poly(alpha-hydroxy acid) and combinations thereof. Examples of nonbiodegradable polymers that may be foamed or otherwise rendered porous include polyurethane, polycarbonate, silicone elastomers, etc. Substance delivery reservoir  3322  may also include one or more embodiments disclosed in U.S. patent application Ser. No. 10/912,578 entitled “Implantable Device and Methods for Delivering Drugs and Other Substances to Treat Sinusitis and Other Disorders” filed on Aug. 4, 2004, the entire disclosure of which is expressly incorporated herein by reference. The substance delivery reservoir  3322  or any substance delivery devices described in this application may be used to deliver various types of therapeutic or diagnostic agents. The term “diagnostic or therapeutic substance” as used herein is to be broadly construed to include any feasible drugs, prodrugs, proteins, gene therapy preparations, cells, diagnostic agents, contrast or imaging agents, biologicals, etc. Such substances may be in bound or free form, liquid or solid, colloid or other suspension, solution or may be in the form of a gas or other fluid or non-fluid. For example, in some applications where it is desired to treat or prevent a microbial infection, the substance delivered may comprise pharmaceutically acceptable salt or dosage form of an antimicrobial agent (e.g. antibiotic, antiviral, antiparacytic, antifungal, etc.), a corticosteroid or other anti-inflammatory (e.g. an NSAID), a decongestant (e.g. vasoconstrictor), a mucous thinning agent (e.g. an expectorant or mucolytic), an agent that prevents or modifies an allergic response (e.g. an antihistamine, cytokine inhibitor, leucotriene inhibitor, IgE inhibitor), etc. 
     Some nonlimiting examples of antimicrobial agents that may be used in this invention include acyclovir, amantadine, aminoglycosides (e.g. amikacin, gentamicin and tobramycin), amoxicillin, amoxicillinlclavulanate, amphotericin B, ampicillin, ampicillinlsulbactam, atovaquone, azithromycin, cefazolin, cefepime, cefotaxime, cefotetan, cefpodoxime, ceflazidime, ceflizoxime, ceftriaxone, cefuroxime, cefuroxime axetil, cephalexin, chloramphenicol, clotrimazole, ciprofloxacin, clarithromycin, clindamycin, dapsone, dicloxacillin, doxycycline, erythromycin, fluconazole, foscarnet, ganciclovir, atifloxacin, imipenemlcilastatin, isoniazid, itraconazole, ketoconazole, metronidazole, nafcillin, nafcillin, nystatin, penicillin, penicillin G, pentamidine, piperacillinitazobactam, rifampin, quinupristin-dalfopristin, ticarcillinlclavulanate, trimethoprimlsulfamethoxazole, valacyclovir, vancomycin, mafenide, silver sulfadiazine, mupirocin (e.g. Bactroban, Glaxo SmithKline, Research Triangle Park, N.C.), nystatin, triarncinolonelnystatin, clotrimazolelbetamethasone, clotrimazole, ketoconazole, butoconazole, miconazole, tioconazole; detergent-like chemicals that disrupt or disable microbes (e.g. nonoxynol-9, octoxynol-9, benzalkonium chloride, menfegol, and N-docasanol); chemicals that block microbial attachment to target cells and/or inhibit entry of infectious pathogens (e.g. sulphated and sulphonated polymers such as PC-515 (carrageenan), Pro-2000, and Dextrin 2 Sulphate); antiretroviral agents (e.g. PMPA gel) that prevent retroviruses from replicating in the cells; genetically engineered or naturally occurring antibodies that combat pathogens such as anti-viral antibodies genetically engineered from plants known as “plantibodies”; agents which change the condition of the tissue to make it hostile to the pathogen (such as substances which alter mucosal pH (e.g. Buffer Gel and Acid form)); non-pathogenic or “friendly” microbes that cause the production of hydrogen peroxide or other substances that kill or inhibit the growth of pathogenic microbes (e.g.  Lactobacillus ); antimicrobial proteins or peptides such as those described in U.S. Pat. No. 6,716,813 (Lin et al.), which is expressly incorporated herein by reference, or antimicrobial metals (e.g. colloidal silver). 
     Additionally or alternatively, in some applications where it is desired to treat or prevent inflammation the substances delivered in this invention may include various steroids or other anti-inflammatory agents (e.g. nonsteroidal anti-inflammatory agents or NSAIDS), analgesic agents or antipyretic agents. For example, corticosteroids that have previously administered by intranasal  10  administration may be used, such as beclomethasone (Vancenase.®. or Beconase), flunisolide (Nasalid.®.), fluticas one proprionate (Flonase.®.), triamcinolone acetonide (Nasacort.®.), budesonide (Rhinocort Aqua.®.), loterednol etabonate (Locort) and mometasone (Nasonex.®.). Other salt forms of the aforementioned corticosteroids may also be used. Also, other non-limiting examples of steroids that may be useable in the present invention include but are not limited to aclometasone, desonide, hydrocortisone, betamethasone, clocortolone, desoximetasone, fluocinolone, flurandrenolide, mometasone, prednicarbate, amcinonide, desoximetasone, diflorasone, fluocinolone, fluocinonide, halcinonide, clobetasol, augmented betamethasone, diflorasone, halobetasol, prednisone, dexarnethasone and methylprednisolone. Other anti-inflammatory, analgesic or antipyretic agents that may be used include the Nonselective COX Inhibitors (e.g. salicylic acid derivatives, aspirin, sodium salicylate, choline magnesium trisalicylate, salsalate, diflunisal, sulfasalazine and olsalazine; para-aminophenol derivatives such as acetaminophen; indole and indene acetic acids such as indomethacin and sulindac; heteroaryl acetic acids such as tolmetin, dicofenac and ketorolac; arylpropionic acids such as ibuprofen, naproxen, flurbiprofen, ketoprofen, fenoprofen and oxaprozin; anthranilic acids (fenamates) such as mefenamic acid and meloxicam; enolic acids such as the oxicams (piroxicam, meloxicam) and alkanones such as nabumetone) and Selective COX-2 Inhibitors (e.g. diaryl-substituted furanones such as rofecoxib; diaryl-substituted pyrazoles such as celecoxib; indole acetic acids such as etodolac; and sulfonanilides such as nimesulide). 
     Additionally or alternatively, in some applications, such as those where it is desired to treat or prevent an allergic or immune response and/or cellular proliferation, the substances delivered in this invention may include a) various cytokine inhibitors such as humanized anti-cytokine antibodies, anti-cytokine receptor antibodies, recombinant (new cell resulting from genetic recombination) antagonists, or soluble receptors; b) various leucotriene modifiers such as zafirlukast, montelukast and zileuton; c) immunoglobulin E (IgE) inhibitors such as Omalizumab (an anti-IgE monoclonal antibody formerly called rhu Mab-E25) and secretory leukocyte protease inhibitor; and d) SYK Kinase inhibitors such as an agent designated as “R-112” manufactured by Rigel Pharmaceuticals, Inc., South San Francisco, Calif. 
     Additionally or alternatively, in some applications, such as those where it is desired to shrink mucosal tissue, cause decongestion, or effect hemostasis, the substances delivered in this invention may include various vasoconstrictors for decongestant and or hemostatic purposes including but not limited to pseudoephedrine, xylometazoline, oxymetazoline, phenylephrine, epinephrine, etc. 
     Additionally or alternatively, in some applications, such as those where it is desired to facilitate the flow of mucous, the substances delivered in this invention may include various mucolytics or other agents that modify the viscosity or consistency of mucous or mucoid secretions, including but not limited to acetylcysteine. In one particular embodiment, the substance delivered by this invention comprises a combination of an anti-inflammatory agent (e.g. a steroid or an NSAID) and a mucolytic agent. 
     Additionally or alternatively, in some applications such as those where it is desired to prevent or deter histamine release, the substances delivered in this invention may include various mast cell stabilizers or drugs which prevent the release of histamine such as crornolyn (e.g. Nasal Chroma) and nedocromil. 
     Additionally or alternatively, in some applications such as those where it is desired to prevent or inhibit the effect of histamine, the substances delivered in this invention may include various antihistamines such as azelastine (e.g. Astylin) diphenhydramine, loratidine, etc. 
     Additionally or alternatively, in some embodiments such as those where it is desired to dissolve, degrade, cut, break or remodel bone or cartilage, the substances delivered in this invention may include substances that weaken or modify bone and/or cartilage to facilitate other procedures of this invention wherein bone or cartilage is remodeled, reshaped, broken or removed. One example of such an agent would be a calcium chelator such as EDTA that could be injected or delivered in a substance delivery implant next to a region of bone that is to be remodeled or modified. Another example would be a preparation consisting of or containing bone degrading cells such as osteoclasts. Other examples would include various enzymes of material that may soften or break down components of bone or cartilage such as collagenase (CGN), trypsin, trypsin1EDTA, hyaluronidase, and tosyllysylchloromethane (TLCM). 
     Additionally or alternatively, in some applications, the substances delivered in this invention may include other classes of substances that are used to treat rhinitis, nasal polyps, nasal inflammation, and other disorders of the ear, nose and throat including but not limited to anti-cholinergic agents that tend to dry up nasal secretions such as ipratropium (Atrovent Nasal.®.), as well as other agents not listed here. 
     Additionally or alternatively, in some applications such as those where it is desired to draw fluid from polyps or edematous tissue, the substances delivered in this invention may include locally or topically acting diuretics such as furosemide and/or hyperosmolar agents such as sodium chloride gel or other salt preparations that draw water from tissue or substances that directly or indirectly change the osmolar content of the mucous to cause more water to exit the tissue to shrink the polyps directly at their site. 
     Additionally or alternatively, in some applications such as those wherein it is desired to treat a tumor or cancerous lesion, the substances delivered in this invention may include antitumor agents (e.g. cancer chemotherapeutic agents, biological response modifiers, vascularization inhibitors, hormone receptor blockers, cryotherapeutic agents or other agents that destroy or inhibit neoplasia or tumorigenesis) such as alkylating agents or other agents which directly kill cancer cells by attacking their DNA (e.g. cyclophosphamide, isophosphamide), nitrosoureas or other agents which kill cancer cells by inhibiting changes necessary for cellular DNA repair (e.g. carmustine (BCNU) and lomustine (CCNU)), antimetabolites and other agents that block cancer cell growth by interfering with certain cell functions, usually DNA synthesis (e.g. 6 mercaptopurine and 5-fluorouracil (5FU), antitumor antibiotics and other compounds that act by binding or intercalating DNA and preventing RNA synthesis (e.g. doxorubicin, daunorubicin, epirubicin, idarubicin, mitomycin-C and bleomycin) plant (vinca) alkaloids and other antitumor agents derived from plants (e.g. vincristine and vinblastine), steroid hormones, hormone inhibitors, hormone receptor antagonists and other agents which affect the growth of hormone-responsive cancers (e.g. tamoxifen, herceptin, aromatase inhibitors such as aminoglutethamide and formestane, trriazole inhibitors such as letrozole and anastrazole, steroidal inhibitors such as exemestane), antiangiogenic proteins, small molecules, gene therapies and/or other agents that inhibit angiogenesis or vascularization of tumors (e.g. meth-I, meth-2, thalidomide), bevacizumab (Avastin), squalamine, endostatin, angiostatin, Angiozyme, AE-941 (Neovastat), CC-5013 (Revimid), medi-522 (Vitaxin), 2-methoxyestradiol (2ME2, Panzem), carboxyamidotriazole (CAI), combretastatin A4 prodrug (CA4P), SU6668, SU11248, BMS-275291, COL-3, EMD 121974, IMC-1C11, 1M862, TNP-470, celecoxib (Celebrex), rofecoxib (Vioxx), interferon alpha, interleukin-12 (IL-12) or any of the compounds identified in Science Vol. 289, pages 1197-1201 (Aug. 17, 2000), which is expressly incorporated herein by reference, biological response modifiers (e.g. interferon, bacillus calmetteguerin (BCG), monoclonal antibodies, interluken 2, granulocyte colony stimulating factor (GCSF), etc.), PGDF receptor antagonists, herceptin, asparaginase, busulphan, carboplatin, cisplatin, carmustine, cchlorambucil, cytarabine, dacarbazine, etoposide, flucarbazine, fluorouracil, gemcitabine, hydroxyurea, ifosphamide, irinotecan, lomustine, melphalan, mercaptopurine, methotrexate, thioguanine, thiotepa, tomudex, topotecan, treosulfan, vinblastine, vincristine, mitoazitrone, oxaliplatin, procarbazine, streptocin, taxol, taxotere, analogslcongeners and derivatives of such compounds as well as other antitumor agents not listed here. 
     Additionally or alternatively, in some applications such as those where it is desired to grow new cells or to modify existing cells, the substances delivered in this invention may include cells (mucosal cells, fibroblasts, stem cells or genetically engineered cells) as well as genes and gene delivery vehicles such as plasmids, adenoviral vectors or naked DNA, mRNA, etc. injected with genes that code for anti-inflammatory substances, etc., and, as mentioned above, osteoclasts that modify or soften bone when so desired, cells that participate in or effect mucogenesis or ciliagenesis, etc. 
     Additionally or alternatively to being combined with a device and/or a substance releasing modality, it may be ideal to position the device in a specific location upstream in the mucous flow path (i.e. frontal sinus or ethmoid cells). This could allow the deposition of fewer drug releasing devices, and permit the “bathing” of all the downstream tissues with the desired drug. This utilization of mucous as a carrier for the drug may be ideal, especially since the concentrations for the drug may be highest in regions where the mucous is retained; whereas non-diseased regions with good mucous flow will be less affected by the drug. This could be particularly useful in chronic sinusitis, or tumors where bringing the concentration of drug higher at those specific sites may have greater therapeutic benefit. In all such cases, local delivery will permit these drugs to have much less systemic impact. Further, it may be ideal to configure the composition of the drug or delivery system such that it maintains a loose affinity to the mucous, permitting it to distribute evenly in the flow. Also, in some applications, rather than a drug, a solute such as a salt or other mucous soluble material may be positioned at a location whereby mucous will contact the substance and a quantity of the substance will become dissolved in the mucous thereby changing some property (e.g. pH, osmolarity, etc.) of the mucous. In some cases, this technique may be used to render the mucous hyperosmolar so that the flowing mucous will draw water and/or other fluid from polyps, edematous mucosal tissue, etc., thereby providing a drying or desiccating therapeutic effect. 
     The above-described treatments of the Eustachian tube of a patient allow for advancing a treatment device through the guide catheter toward the Eustachian tube to place a distal tip of the treatment device adjacent the Eustachian tube opening. It may be preferred for the treatment device to have distal radiopaque member. The treatment device may include a catheter. 
     Alternatively or in addition, the treatment device can include a fluid introduction device for introducing a fluid into a middle ear space of the patient&#39;s ear. The fluid may be air, a contrast medium, an aspiration fluid, or a drug such as those described above. The treatment method can also include scanning the middle ear space using an ultrasound device. Alternatively, or in addition, the treatment device can include an aspiration device for aspirating a substance from the middle ear space. 
     Alternatively or in addition, the treatment may also include introducing a protective device proximal the Eustachian tube, and monitoring advancement of the treatment device using the protective device. The protective device may be a sensor positioned proximal the tympanic membrane to sense the position of the treatment device during the advancement. Alternatively, the protective device may comprise an endoscope to visualize the advancement. 
     Alternatively, or in addition, the method for treating a Eustachian tube in a patient includes placing a dual lumen pressure equalization tube through the tympanic membrane of the patient, the tube having a distal extension for location in a region of the Eustachian tube; providing a medication to the region of the Eustachian tube through a first lumen of the dual lumen tube in fluid communication with the distal extension; and providing ventilation across the tympanic membrane through a second lumen of the dual lumen tube. The medication is used to reduce edema in the Eustachian tube region. 
     The medication may also include surfactant configured to modify a surface tension of a mucosal layer of the Eustachian tube to effect an enhanced wetting of the mucosal surface with the medication. The medication may also include particles that are used for capturing by mucosal tissue of the Eustachian tube to effect an extended release of the medication. Exemplary surfactants are disclosed in U.S. Pat. No. 6,616,913, entitled “Composition and Method for Treatment of Otitis Media”, the disclosure of which is incorporated herein by reference. 
     In another embodiment, the present invention is directed to an apparatus for treating a Eustachian tube in a patient. The apparatus includes a dual lumen tube for insertion into a tympanic membrane of the patient&#39;s ear. The tube can include a distal extension for placement in a region of the Eustachian tube, a first lumen for providing a medication to the region of the Eustachian tube through the distal extension, and a second lumen for providing ventilation across the tympanic membrane. 
     The first lumen may be disposed within the second lumen. Alternatively, the second lumen is disposed within the first lumen. Additionally or alternatively, the first lumen is disposed adjacent the second lumen. The dual lumen tube may be made from or it may include a biodegradable bioresorbable material. 
     In another embodiment, the present invention is directed to the treatment of the Eustachian tube by delivering a drug to the Eustachian tube. The method comprises accessing a Eustachian tube region via the nasopharynx, using a guide having a lumen; introducing a guidewire through the lumen of the guide to position it submucosally between cartilage and a mucosal surface of the Eustachian tube; passing a temporary intraluminal implant having a drug delivery reservoir along the guidewire to position the implant submucosally in a posterior cushion of the Eustachian tube region between the lumen and the cartilage; and delivering a drug to the Eustachian tube region from the drug delivery reservoir. 
     In addition, the method may also include contemporaneously delivering a drug to adenoids and the Eustachian tube region from the drug delivery reservoir. In one embodiment, the drug delivery reservoir can comprise a coating layer disposed on the implant. In another embodiment, the guide comprises a biodegradable bioresorbable material. 
     In another embodiment, the treatment of the Eustachian tube in a patient includes obtaining access to a Eustachian tube region via the nasopharynx, introducing via the patient&#39;s nasopharynx a hollow guidewire dimensioned to reach into the Eustachian tube region, the hollow guidewire comprising a plurality of apertures disposed at or near its distal end, and delivering a drug to at least one of the Eustachian tube or a middle ear region of the patient&#39;s ear through the apertures. 
     In another embodiment, drug may be delivered to tissue in the Eustachian tube via iontophoresis. In this embodiment, a drug fluid may be passed into the Eustachian tube, and an electrical current may be applied to the fluid to drive ions of the drug across a tissue, such as mucous membrane or a tympanic membrane. 
     In another embodiment, the present invention is directed toward a system for accessing a Eustachian tube of a patient. The system can include a guide configured for passing into a nasal passage of the patient to position a distal tip of the catheter at or near a Eustachian tube, the guide having a distal tip with a bend having an angle between 30 and 90 degrees; and a guidewire configured to pass through the guide into the Eustachian tube. 
     In one embodiment, the guide comprises a catheter. In another embodiment, the guide comprises a dual lumen tube. In another embodiment, the system may also include a diagnostic device configured for passage through the guide. In another embodiment, the system may also include a treatment device configured for passage through the guide. 
     Non-Guidewire Devices 
       FIG. 15A  shows a device  1500  for treating a Eustachian tube, according to one embodiment. The device  1500  includes an elongate rigid shaft  1502 . The rigid shaft may be constructed from a semi-flexible metal or plastic. “Rigid” as used with regards to device  1500  means that the shaft  1502  will not deform when inserting the shaft  1502  into a nasal cavity. The rigid shaft  1502  may be formed from a malleable material and custom bent for use in the field. A therapeutic device, which in this example is an elongate flexible insert  1504 , is coupled to the distal portion of the rigid shaft  1502 . A stop may be placed at the insert  1504 /shaft  1502  junction to prevent the shaft from entering a Eustachian tube. The insert  1504  preferentially includes a lateral stiffness such that when inserted into a Eustachian tube, the insert  1504  will conform to the pathway of the Eustachian tube and not cause significant deformation of the Eustachian tube. The insert  1504  may also include a preformed shape (not shown), for example which is preformed to the anatomy of a Eustachian tube. The insert  1504  preferentially includes a column stiffness strong enough to insert into a Eustachian tube without collapsing on itself or buckling. This example of an insert  1504  includes a core wire  1506  and an expandable balloon  1508 . The core wire  1506  may be constructed from metal, such as stainless steel, or a super-elastic alloy such as nickel-titanium. Core wire  1508  diameters in the range of 0.05-0.25 mm may be suitable. The balloon  1508  may be of compliant, semi-compliant, or non-compliant construction. The balloon  1508  may include a preformed shape which matches the profile of a Eustachian tube. The balloon  1508  may include micropores for delivery, upon partial or full expansion, of any of the therapeutic substances disclosed herein. The balloon  1508  may include a coating for delivery of any of the therapeutic substances disclosed herein. The device  1500  may include an atraumatic tip  1510  in the shape of a ball, which may be integral to the core wire  1506 . The device  1500  may include a fitting  1511  at the proximal portion of the shaft  1502  for supplying fluid, energy and electrical signals to the insert  1504 . The device  1500  may accordingly include a lumen for passage of fluids. The device  1500  does not require a guidewire for insertion into a Eustachian tube, however a guidewire may be optionally used. 
     The device  1500  may be manually inserted by grasping the shaft  1502  and guiding the insert into a nasal passage and nasopharynx, and into the Eustachian tube, by way of a scope, fluoroscopy, or transillumination. Accordingly, portions of the device  1500  may include radiopaque coatings or materials. The insert  1504  may include fiber optics for transmitting light for transillumination. Examples of transilluminating devices are shown in co-assigned U.S. patent application Ser. Nos. 10/829,917 and Ser. No. 11/522,497, both of which are herein incorporated by reference in their entireties. The insert  1504  may also include a CCD or CMOS camera and associated wiring for endoscopic viewing without a separate scope. The device  1500  may also be linked to a 3-D tracking system. 
     The insert  1504  shown is merely an example and may include other constructions, such as a bare wire. The bare wire may deliver energy, for example resistive heat, ultrasonic, or electrosurgical energy (e.g. RF). Energy may also be delivered by the balloon  1504 , for example by a hot fluid or gas. 
     The insert  1504  may also deliver a stent for supporting or expanding the Eustachian tube. The stent may include a polymer material, which may elute any of the therapeutic substances disclosed herein. 
     The insert  1504  may also be detachable from the shaft  1504  for delivery into the Eustachian tube. In one example, the insert  1504  may be constructed from a biodegradable polymer, such as polylactic acid, which may also include any of the therapeutic substances disclosed herein. The insert  1504  may then degrade over time and deliver a therapeutic substance as required. The biodegradable insert  1504  may also include a lumen for drainage of fluid in the Eustachian tube. 
       FIG. 15B  shows an alternative device  1512  for treating a Eustachian tube, according to one embodiment. The device  1512  is largely constructed as shown in  FIG. 15A , however this embodiment includes a rigid shaft  1514  which includes a preferential bend  1516 . The bend  1516  may range from 30 to 90 degrees. The bend  1516  allows for easier access to the Eustachian tube in certain anatomies. 
       FIG. 15C  shows the device  1500  or  1512  in use, according to one embodiment. The device  1500  is shown with the insert  1504  placed within a Eustachian tube ET. The insert  1504  preferentially deforms to match the profile of the Eustachian tube ET, and thus may deliver a therapy without deforming or damaging the Eustachian tube ET. Alternatively, the insert  1504  is preformed to match the profile of the Eustachian tube and deforms slightly while being positioned. The insert  1504  also includes a column stiffness which is significant enough to prevent buckling of the insert during insertion into the Eustachian tube ET, and thus prevent damage to the device or Eustachian tube ET. 
       FIG. 15D  shows the device  1500  or  1512  in use, according to one embodiment. In this embodiment the device  1500  includes a stent  1518  which may be expanded within the Eustachian tube ET. The stent may include a shape-memory alloy construction or a deformable construction which is expanded by the balloon  1508 . 
       FIG. 15D  shows the device  1500  or  1512  in use, according to one embodiment. In this embodiment the device  1500  includes a detachable insert  1520 . The detachable insert may be detached at junction  1522 . In this example, the insert  1520  includes a lumen. The insert  1520  may be biodegradable and deliver a therapeutic substance over time. In one embodiment, the insert  1520  may include an attachment member for attaching the insert  1520  to mucosal tissue within the nasal cavity, so that the insert  1520  will not migrate from the area into which it is placed. This attachment member (or multiple members) may be attached to the insert  1520  at or near its proximal end, so that when the insert  1520  is placed in the Eustachian tube, the attachment member extends into the nasal cavity and can be attached by the physician to the mucosal tissue. Any suitable attachment member may be used in various embodiment, such as but not limited to a suture loop, clips, barbs or the like. 
       FIG. 15F  shows another alternative embodiment of a guidewire-free Eustachian tube dilation device  1530 . In this embodiment, the dilation device  1530  includes a handle  1532  coupled with a sliding balloon catheter  1540  and a malleable guide member (or “shaft”)  1544  over which the balloon catheter  1540  slides. Also coupled with the handle  1532  are a suction port  1534 , an inflation port  1536 , and a sliding actuator  1538  for advancing and retracting the balloon catheter  1540  along the guide member  1544 . In this embodiment, the balloon catheter includes a rigid proximal portion  1541 , a distal flexible portion  1546 , and an inflatable balloon  1548 . The guide member  1544  may include a ball tip  1542  similar to those found on a distal end of a ball-tip seeker frequently used by ENT physicians during sinus surgery. Proximal shaft portion  1541  may be made of any suitable material. For example, in one embodiment, the proximal shaft portion  1541  may be a stainless steel hypotube. The flexible distal shaft portion  1546  may be made of any flexible material, such as a flexible polymer, and the balloon  1548  may be made of any suitable non-compliant, semi-compliant or compliant material, including but not limited to PET, Nylon or Pebax. In various embodiments, the guide member  1544  may be flexible, malleable or rigid, and may be made of stainless steel, Nitinol or any other suitable material. 
     In use, the dilation device  1530  may be advanced into a nostril, and the guide member  1544 , with its ball tip  1542 , may be used to seek out and locate the opening to a Eustachian tube, much the same way that ENT physicians use a ball tip seeker to find the opening of a paranasal sinus. Once the Eustachian tube opening is located, the guide member  1544  may be advanced through the opening, and the sliding actuator  1538  may be advanced along a slot (not visible in  FIG. 15F ) in the handle  1532  to advance the balloon catheter  1540  along the guide member  1544 . The balloon catheter  1546  is advanced to position the balloon  1548  at a desired location within the Eustachian tube. The balloon  1548  may then be inflated via inflation port  1536  to expand/dilate a portion of the Eustachian tube, and the balloon  1548  may then be deflated. The balloon  1548  may subsequently either be removed from the patient, repositioned within the same Eustachian tube to dilate additional portions, or repositioned to the contralateral Eustachian tube to dilate that tube. The procedure may be performed as many times and in any combinations of locations as desired on a patient. In some embodiments, the dilation device  1530  may also be used to dilate an opening into a paranasal sinus (or multiple paranasal sinus openings). The paranasal sinus opening dilation may be performed before and/or after the Eustachian tube dilation and may involve openings into the frontal, sphenoid, maxillary or ethmoid sinuses. In some embodiments, the dilation device  1530  may be removed from the patient between dilations to allow the user to bend a malleable portion of the guide member  1544  to different angles to facilitate accessing different sinus and/or Eustachian tube openings. 
     In an alternative embodiment, the guide member  1544  may be an outer tube through which the balloon catheter  1540  advances. Such a tube may be predominantly rigid, part rigid/part flexible, or mostly flexible. In another alternative embodiment, the guide member  1544  may include both an inner shaft and an outer tube. In yet another embodiment, the balloon catheter  1540  may be fixedly attached to the guide member  1544  (or shaft). In another embodiment, there may be no guide member but simply a rigid or partially rigid and/or malleable balloon catheter  1540 , which may be advanced into the Eustachian tube by itself without using a guide. In other embodiments, any other suitable dilation device may be substituted for the balloon catheter  1540 , such as but not limited to a mechanical dilator such as an expandable metal basket including multiple tines. 
       FIGS. 16A and 16B  show a method for providing therapy to a Eustachian tube of a patient, according to one embodiment. Before the treatment method is performed, the physician may apply a local anesthesia to the nasal cavity and/or the Eustachian tube. In cases performed under general anesthesia, the physician may choose not to apply local anesthesia, while in cases performed on a conscious patient, local anesthetic may be applied. In general, the method may include any preparation/anesthesia technique desired. In some embodiments, for example, a physician may choose to irrigate the nasal cavity and/or Eustachian tube before performing a treatment. This may be in addition to anesthesia or in cases where local anesthesia is not applied. 
     After any desired preparation of the nasal cavity and/or Eustachian tube, a guide catheter  1600  may be routed through a nasal passage of a patient and placed adjacent to the opening of a Eustachian tube ET. In various embodiments, the guide catheter  1600  may be advanced to a Eustachian tube through either the ipsilateral or contralateral nostril, and generally the guide catheter  1600  will have a different bend angle depending on the approach. In the embodiment shown, a distal portion  1602  of the guide catheter  1600  includes a bend having an angle between 30 and 90 degrees (or any other angles in alternative embodiments). In one embodiment, the distal portion  1602  may be more flexible than the proximal portion of the guide catheter  1600 . In one embodiment, the distal portion  1602  of the guide catheter may be malleable. Accordingly, a user may bend the distal portion  1602  to place the guide catheter  1600  in a desired position with relation to the Eustachian tube ET. 
     After the guide catheter  1600  is in a desired position, a guidewire  1604  may then be advanced through the guide catheter  1600  and into the Eustachian tube ET. In the embodiment shown, the guidewire  1604  includes a ball tip  1603  to prevent passage of the guidewire  1604  through a distal, small diameter portion of the Eustachian tube. Other embodiments may include a curved distal tip or other stop mechanism to achieve the same purpose. As mentioned above, although this embodiment of a method for treating a Eustachian tube involves the guide catheter  1600  and guidewire  1604 , alternative treatment methods may involve a guide catheter  1600  alone, a guidewire  1604  alone, or may be performed without any guide device. 
     In  FIG. 16B , a dilation catheter  1606  is advanced over the guidewire  1604  and through the guide catheter  1600  to position a dilator  1608  of the dilation catheter  1606  within the Eustachian tube ET. In an alternative embodiment, the guide catheter  1600  may be optionally removed from the patient before advancing the dilation catheter  1606  over the guidewire  1604 . In another alternative embodiment, the dilation catheter  1606  may be advanced into the Eustachian tube through the guide catheter  1600  without using a guidewire  1604 . The dilation catheter  1606  generally includes an elongate shaft and the dilator  1608 . The dilator  1608  may be a polymer balloon (compliant, semi-compliant or non-compliant). In some embodiments, the balloon may be porous, to deliver a therapeutic or diagnostic agent when pressurized. Alternatively, the dilator  1608  may be a mechanically expandable basket constructed from a plurality of metal or polymer tines or any of a number of other suitable mechanical dilation devices. The dilation catheter  1606  generally includes proximally located connections/provisions for inflating/activating the dilator  1608 . A therapeutic or diagnostic agent may be applied to the interior of the Eustachian tube ET before or after the insertion of the dilation catheter  1606 , for example, via a spray catheter or a spray lumen of the guide catheter  1600 . In one embodiment, for example, the dilation catheter  1606  may include a fluid introduction lumen (or multiple lumens) for introducing irrigation fluid, anesthetic fluid, therapeutic drug or other substances into the Eustachian tube. In one embodiment, this same lumen or a separate lumen may be used to suction fluids/substances out of the Eustachian tube. 
     The dilator  1608  may be expanded to dilate the Eustachian tube ET after it is placed in a desirable location therein. For example, the opening area of the Eustachian tube ET includes a pharyngeal ostium, and the dilation catheter  1606  may be advanced to position the dilator  1608  in the pharyngeal ostium. An endoscope may be used to assist in positioning the dilation catheter  1606 . The endoscope may be advanced through the nasal passage to view the dilation catheter  1606 . A marker on a shaft of the dilation catheter  1606  can be viewed from the endoscope to approximate a location of the dilator  1608  relative to the opening of the Eustachian tube ET based on a distance of the marker from a proximal end of the dilator  1608 . Accordingly, the dilation catheter  1606  can be moved to place the marker in a desirable location before expansion of the dilator  1608  in the Eustachian tube ET. 
     The dilator  1608  may be held in location while in an expanded state for an extended period of time (e.g. several seconds or minutes). The dilator  1608  may also deliver a substance to the Eustachian tube ET, such as one or more of the therapeutic or diagnostic agents described herein. The dilator  1608  may also carry an expandable stent for delivery into the Eustachian tube upon expansion of the dilator  1608 . The dilation catheter  1606 , guide catheter  1600  and guidewire  1604  may be removed from the patient after the dilator is  1608  has been deflated/unexpanded. 
     As mentioned above, in an alternative embodiment, a balloon dilation catheter may sometimes be capable of being advanced into and used within a Eustachian tube without the use of a guidewire, guide catheter or other guiding device. Such a balloon catheter would need to have sufficient overall stiffness to allow it to be passed through the nasal cavity and into the Eustachian tube without a guide device, but ideally at least a distal portion of the catheter would also be flexible enough to advance into and conform to the shape of the tortuous Eustachian tube without causing unwanted damage. In some embodiments, such a balloon dilation catheter may have an adjustable stiffness along at least a portion of its length. For example, in one embodiment the catheter may have a malleable portion that a physician user may adjust with his/her hand before insertion. It may be even more advantageous, however, to have a catheter that may be advanced into the Eustachian tube with one amount of stiffness and then adjusted to a different amount of stiffness. For example, it may be desirable to have a catheter that is relatively stiff until its distal end has passed into the Eustachian tube and then can be made more flexible for tracking farther into the Eustachian tube. In one embodiment, this adjustable stiffness may be achieved using a sliding stiffening mandrel that extends into the distal portion of the catheter in which the stiffness adjustment is desired and extends proximally to a slide member on a handle or proximal portion of the catheter, which the user uses to make the adjustment. In other embodiments, the stiffening member (or members) may comprise one or more core wires, ribbons, compressible fluids or the like. The proximal member used to control the stiffness may comprise a slide, dial, button or other actuator. 
       FIG. 17  shows an illuminated guidewire  1700  in use, according to one embodiment. The illuminated guidewire  1700  is used in the same manner as the guidewire  1604  described above. However, the illuminated guidewire  1700  provides illumination at a distal tip  1702 , which is visible to a user through the tympanic membrane or on the external face of the patient (commonly referred to as “transillumination”). The user may place the distal tip  1702  at a desired location based on the position of a light point  1704  passing through the patient&#39;s tissue. The light point  1704  may be used as a point of reference for the placement of other devices based on the relative distance from the light point  1704 . The light point  1704  may also provide a secondary or primary light source for an endoscope which is viewing the pharyngeal ostium of the Eustachian tube ET. The illuminated guidewire  1700  may include a fiber optic channel for passing light from a light source to the distal tip  1702 . Examples of illuminated guidewires and scopes which may be used in conjunction with this disclosure are shown and described in commonly assigned U.S. patent application Ser. No. 11/522,497, the entirety of which is incorporated by reference herein. 
       FIGS. 18A and 18B  show a dilation catheter  1800  according to an alternative embodiment. The dilation catheter  1800  includes a detachable dilator  1802 . The detachable dilator  1802  may be detached from the dilation catheter  1800  after the detachable dilator  1802  has been expanded within the Eustachian tube ET. The detachable dilator  1802  may include a one-way valve, which allows the detachable dilator  1802  to remain dilated after detachment from the dilation catheter  1800 . A breakable joint may join the detachable dilator  1802  and the dilation catheter  1800 . The detachable dilator  1802  may include at least one lumen to allow the passage of a pressurizing fluid. In use, the dilation catheter  1800  may be positioned and expanded to dilate a portion of the Eustachian tube as described for previous embodiments. After the detachable dilator  1802  is inflated, it may be detached at the breakable joint via a twisting or pulling force applied at the proximal portion of the dilation catheter  1800 . The one-way valve prevents the detachable dilator  1802  from deflating after detachment from the dilation catheter  1800 . The detachable dilator  1802  may include a therapeutic or diagnostic agent to treat the Eustachian tube ET. Pressure within the Eustachian tube ET may be balanced via the lumen while the detachable dilator  1802  remains dilated therein. The detachable dilator  1802  may be removed by pulling it out of the Eustachian tube ET and in some embodiments by also puncturing the detachable dilator  1802 . 
       FIG. 18C  shows a dilation catheter  1804  according to an alternative embodiment. The dilation catheter  1804  includes a plurality of extendable needles  1806 , which may extend through passages in the dilator  1808 . Each needle  1806  can be fluidly connected to a therapeutic or diagnostic agent source, such as a syringe. Different needles  1806  can be connected to different kinds of therapeutic or diagnostic agents. In use, the dilation catheter  1800  may be positioned and expanded to dilate a portion of the Eustachian tube as described for previous embodiments. After the dilator  1808  is inflated, the needles  1806  may be advanced through the dilator  1808  and into tissue of the Eustachian tube ET. The needles  1806  may then inject one or more kinds of therapeutic or diagnostic agents into the tissue of the Eustachian tube ET as shown by the substance plumes P. After the substance has been injected into the tissue of the Eustachian tube ET, the needles may be withdrawn back into the dilation catheter  1804  and the dilation catheter  1804  may be removed from the Eustachian tube ET. 
       FIG. 18D  shows a dilation catheter  1810  according to an alternative embodiment of the dilation catheter  1606 . The dilation catheter  1810  includes at least one pair of opposed lateral wings  1812 , which help maintain the position of the dilator  1814  in the Eustachian tube ET. More than one pair of opposed lateral wings  1812  may be used. The lateral wings  1812  do not have to be positioned directly opposite each other, and configurations of odd-numbered lateral wings  1812  may be used. The lateral wings  1812  can be constructed from elongate tines which are spring biased to expand when advanced out of the shaft  1816  of the dilation catheter  1810 . Withdrawing the slidably housed lateral wings  1812  will cause them to collapse within the shaft  1816 . The lateral wings  1812  can be manipulated at the proximal end of the dilation catheter  1810 , for example, through actuation of a slider mechanism. The lateral wings  1812  can include spikes or grips to help maintain immovable contact with the Eustachian tube ET. In use, the dilator  1814  and lateral wings  1812  are advanced out of the shaft  1816  simultaneously, or non-simultaneously (i.e. the lateral wings  1812  may be advanced before or after the dilator  1814 ). The lateral wings  1812  apply force to the walls of the opening of the Eustachian tube ET, which helps maintain the dilator  1814  in a desired position. The lateral wings  1812  may be withdrawn back into the shaft  1816  after the dilator  1814  has applied the desired therapy to the Eustachian tube ET. 
       FIGS. 18E-T  show various views of alternative embodiments of the dilator  1608 . For instance,  FIGS. 18E-G  show a dilator  1817  that has a tapered, conical shape, which complements the tapered geometry of the Eustachian tube ET, to enhance dilation thereof. The tapered, conical shape of dilator  1817  is formed by a proximal end  1832 , a tapered proximal surface  1830 , a maximum diameter  1831 , a tapered distal surface  1818 , and a distal end  1833 . In the present example, tapered distal surface  1818  has a longitudinal length of about 12 to 18 millimeters, maximum diameter  1831  has a diameter of about 6.5 millimeters, and proximal end  1832  and distal end  1833  have a diameter of about 4.5 millimeters. Alternatively, any other suitable dimensions may be used. Dilator  1820  may also have a variable shape, such as the stepped shape shown in  FIG. 18H . With this stepped shape, dilator  1820  has at least two different outer diameters—a first outer diameter extending along a proximal length of dilator  1820  and a second outer diameter extending along a distal length of dilator  1820 , with an angled transition between these outer diameters. 
     Problems may arise from dilator  1817 ,  1820  dilating the Eustachian tube ET by making uniform contact along the full circumference of the Eustachian tube ET. When dilator  1817 ,  1820  expands within the Eustachian tube, air is displaced due to the increase in volume of dilator  1817 ,  1820 . If the air travels toward middle ear  14 , rather than toward nasopharynx region of the throat  30 , pressure may build in middle ear  14 , leading to possible damage to tympanic membrane  22 . Pressure may build in part to dilator  1817 ,  1820  acting as a seal within the Eustachian tube ET. Providing fluid communication between proximal end  1832  and distal end  1833  of dilator  1817 , 1820  may help release pressure build up that might otherwise occur in middle ear  14  due to expansion dilator  1817 ,  1820 . In other words, it may be beneficial to provide a vent path that allows air to escape from the lateral region of the Eustachian tube ET as the expanding dilator  1817 ,  1820  begins to occupy the space in the lateral region of the Eustachian tube ET. Also, controlling the direction of the displaced air due to dilator  1817 ,  1820  expansion may also help prevent possible pressure build up in middle ear  14 . The following are merely illustrative examples of different devices and methods that may be utilized to prevent pressure build up in middle ear  14 , while also providing dilation of the Eustachian tube ET. Other examples of devices and methods will be apparent to a person having ordinary skill in the art in view of the teachings herein. It should be understood that the methods and dilator features described below can be combined in various ways in order to help prevent undesired pressure build up in middle ear  14 . 
     As shown in  FIGS. 18E and 18H , dilators  1817 ,  1820  can be attached to shaft  1822  that extends through both proximal end  1832  and distal end  1833  of dilator  1817 ,  1820 . Shaft  1822  comprises a vent lumen  1834  extending through dilator  1817 ,  1820 , a set of proximal pressure relief holes  1824  located proximal to proximal end  1832 , and a set of distal pressure relief holes located distal to and distal end  1833 . Pressure relief holes  1824  are oriented transversely through shaft  1822 . Pressure relief holes  1824  may provide fluid communication between proximal end  1832  and distal end  1833  of dilator  1817 ,  1820  via vent lumen  1834 . This fluid communication path may be utilized to prevent expansion of dilator  1817 ,  1820  from providing pressure build up in middle ear  14 , thereby providing pressure balance within the Eustachian tube ET. In other words, as dilator  1817 ,  1820  is inflated, air in the region of the Eustachian tube ET that is distal to  1817 ,  1820  may escape via pressure relief holes  18240  as the inflating  1817 ,  1820  occupies that distal region of the Eustachian tube ET. The number of pressure relief holes  1824  shown in  FIGS. 18E and 18H  is merely exemplary. Shaft  1822  may include additional or fewer pressure relief holes  1824  if desired. It should also be understood that shaft  1822  would include a separate inflation lumen (not shown) that would be used to inflate/deflate dilator  1817 ,  1820 . Such an inflation lumen would be fluidly isolated from vent lumen  1834 . Moreover, the expandable portions of dilators  1817 ,  1820  would be fluidly isolated from vent lumen  1834 . 
       FIGS. 18I-N  show exemplary dilators  1850 ,  8900 ,  9000 ,  9100 ,  9200  that have a cross-sectional geometry that does not contact and occupy the entirety of the circumference of the Eustachian tube ET, thereby allowing fluid communication between the proximal and distal ends of dilators  1850 ,  8900 ,  9000 ,  9100 ,  9200  when inflated. Thus, as described in greater detail below, the cross-sectional geometry of dilators  1850 ,  8900 ,  9000 ,  9100 ,  9200  prevent a sealing effect from ever occurring. 
       FIGS. 18I-J  show one exemplary cross-sectional geometry with dilator  1850 . Dilator  1850  comprises a proximal end  1856 , a distal end  1851 , a lumen  1853 , a plurality of lobes  1854  separated by a plurality of recesses  1855 , and tapered surfaces  1852 . In the present example, tapered surfaces  1852  are located on both proximal end  1856  and distal end  1851 . However, tapered surfaces  1852  are merely optional, and can be present on one end or not present at all. In the present example, lobes  1854  are angularly spaced equidistantly from each other about a longitudinal axis defined by the shaft  1822 . The cross-sectional shape of dilator  1850  is formed by the successive intervals of lobes  1854  and recesses  1855 ; and generally resembles a “+” sign. The cross-sectional shape of dilator  1850  provides limited contact with Eustachian tube ET when dilator  1850  is inflated, preventing a sealing effect from occurring. In other words, recesses  1855  provide ventilation paths along the length of dilator  1850 . Optionally, as in dilators  1817 ,  1820 , pressure relief holes may be utilized past proximal end  1856  and distal end  1851  to provide additional pressure relief. Additionally, tapered surfaces  1852  do not have to be uniform, but can have dimensional variations similar to that of tapered surfaces  1818 ,  1830  of dilator  1817 , thereby allowing for a complementary fit of dilator  1850  with a Eustachian tube ET of a patient. 
       FIGS. 18K-P  show examples of dilators  8900 ,  9000 ,  9100  that have varying cross-section geometry along the length of dilator  8900 ,  9000 ,  9100 ; yet still provide fluid communication between proximal and distal ends of dilator  8900 ,  9000 ,  9100  when inflated. 
     For example,  FIGS. 18K and 18L  show dilator  8900  comprising a proximal end  8904 , a distal end  8907 , ribs  8901  separated by annular recesses  8902 , longitudinal recesses  8905  extending from proximal end  8904  to distal end  8907 , and a shaft  8903  with a lumen  8904  extending through dilator  8900 . Ribs  8901  are the aspect of dilator in contact with Eustachian tube ET, while annular recesses  8902  and longitudinal recesses  8905  provide pathways for fluid communication between proximal end  8904  and distal end  8907 , thereby preventing any sealing effect that might otherwise lead to unwanted pressure buildup in middle ear  14  upon inflation of dilator  8900 . Optionally, as in dilators  1817 ,  1820 , pressure relief holes may be utilized in shaft  8903  past proximal end  8904  and distal end  8907  of dilator  8900  to provide additional pressure relief. Additionally, dimensions along the length of dilator  8900  do not have to be uniform, but can have dimensional variations similar to that of tapered surfaces  1818 ,  1830  of dilator  1817 , thereby allowing for a complementary fit of dilator  8900  with a Eustachian tube ET of a patient. 
       FIGS. 18M and 18N  show another example where dilator  9000  comprises a proximal end  9004 , a distal end  9005 , a dilator body  9002 , discrete bumps  9001 , and a shaft  9003  with a lumen  9006  extending through dilator  9000 . Discrete bumps  9001  may be either symmetrically or randomly placed along dilator body  9002 . When dilator  9000  inflates, discrete bumps  9001  may come in contact with a Eustachian tube ET of a patient. Discrete bumps  9001  have enough rigidity to act as spacers between dilator body  9002  and a Eustachian tube ET of a patient. By providing space between dilator body  9002  and the Eustachian tube ET, discrete bumps  9001  provide a ventilation path in that space between proximal end  9004  and distal end  9005  of dilator  9000  as dilator  9000  inflates. Fluid communication between proximal end  9004  and distal end  9005  thereby prevents any sealing effect, which might otherwise lead to unwanted pressure buildup in middle ear  14  as dilator  9000  inflates. Optionally, as in dilators  1817 ,  1820 , pressure relief holes may be utilized in shaft  9003  past proximal end  9004  and distal end  9005  of dilator  9000  to provide additional pressure relief. Additionally, dimensions along the length of dilator  9000  do not have to be uniform, but can have dimensional variations similar to that of tapered surfaces  1818 ,  1830  of dilator  1817 , thereby allowing for a complementary fit of dilator  9000  with a Eustachian tube ET of a patient. 
       FIGS. 18O and 18P  show an example where dilator  9100  comprises a proximal end  9102 , a distal end  9104 , a body  9103 , a spiral rib  9101  along the body  9103 , and a shaft  9105  with a lumen  9106  extending through dilator  9100 . Spiral rib  9101  provides contact with a Eustachian tube ET of a patient when dilator  9100  is inflated, preventing dilator body  9103  from providing a sealing effect. In other words, spiral rib  9101  provides a helical vent path along the space defined between body  9103  and the wall of the Eustachian tube ET. Therefore, spiral rib  9101  provides a ventilation path between proximal end  9102  and distal end  9104  of dilator  9100 . Optionally, as in dilators  1817 ,  1820 , pressure relief holes may be utilized on shaft  9105  past proximal end  9102  and distal end  9104  of dilator  9100  to provide additional pressure relief. Additionally, dimensions of along the length of dilator  9100  do not have to be uniform, but can have dimensional variations similar to that of tapered surfaces  1818 ,  1830  of dilator  1817 , thereby allowing for a complementary fit of dilator  9100  with a Eustachian tube ET of a patient. It should be noted that more than one spiral rib  9101  may be used. 
       FIGS. 18Q and 18R  show an example of dilator  9200  comprising a proximal end  9402 , a distal end  9205 , a body  9202 , fins  9201  extending longitudinally along the exterior of body  9202 , and a shaft  9203  with a lumen  9206  extending through proximal end  9204  and distal end  9205 . When dilator  9000  inflates, fins  9201  may come in contact with a Eustachian tube ET of a patient. Fins  9201  have enough rigidity to act as spacers between dilator body  9202  and a Eustachian tube ET of a patient, preventing the wall of the Eustachian tube from sealing against body  9202 . Therefore, fins  9201  provide a ventilation pathway between proximal end  9204  and distal end  9205  of dilator  9200  when fins  9201  are in contact with the Eustachian tube ET as dilator  9200  inflates. Such a ventilation path may prevent unwanted pressure buildup that might otherwise occur in middle ear  14  due to inflation of dilator  9200 . Optionally, as in dilators  1817 ,  1820 , pressure relief holes may be utilized on shaft  9203  past proximal end  9204  and distal end  9205  of dilator  9200  to provide additional pressure relief. Additionally, dimensions of along the length of dilator  9020  do not have to be uniform, but can have dimensional variations similar to that of tapered surfaces  1818 ,  1830  of dilator  1817 , thereby allowing for a complementary fit of dilator  9200  with a Eustachian tube ET of a patient. 
       FIGS. 18S-T  show an example of a dilator  9300  comprising a proximal end  9302 , a distal end  9304 , a body  9307 , a venting tube  9301  that is non-coaxial with body  9307 , and a shaft  9303  with a lumen  9306  extending through proximal end  9302  and distal end  9304  of dilator  9300 . Venting tube  9301  can be attached to body  9307  and therefore inserted simultaneously with body  9307  into a Eustachian tube ET of a patient. Alternatively, venting tube  9301  can be detached from body  9307 , allowing insertion of venting lumen into a Eustachian tube ET of a patient either before or after insertion of body  9307  in a Eustachian tube ET of a patient. Venting tube  9301  has an open distal end and an open proximal end, with a lumen extending therebetween. Venting tube  9301  thus effectively provides a ventilation path between the proximal end  9302  and distal end  9304  of dilator  9300 . Venting is achieved through the inner lumen of venting tube  9301 , through space S ( FIG. 18T ) between the wall of the Eustachian tube ET and regions of the walls of venting tube  9301  and body  9307 , or through a combination of both. The venting prevents a sealing effect, which may otherwise lead to unwanted pressure buildup in middle ear  14  when dilator  9300  is inflated. 
     Providing a path for ventilation through the geometry of dilator  1818 ,  1820 ,  1850 ,  8900 ,  9000 ,  9100 ,  9200 ,  9300  is merely one example of preventing pressure build up in the middle ear  14  during the dilation of the Eustachian tube ET. As another merely illustrative example,  FIGS. 18U-W  show a controlled inflation of a dilator  9500 , forcing air toward the medial region of a Eustachian tube ET of a patient into the nasopharynx region of the throat  30 . In  FIG. 18U , dilator  9500  is in the Eustachian tube ET in a deflated state. In  FIG. 18V , air is introduced to dilator  9500  in such a way that distal end  9501  of dilator  9500  inflates first. Inflating distal end  9501  of dilator  9500  first forces air in the proximal or medial direction as displayed by arrows in  FIGS. 18U-W . Distal end  9501  of dilator  9500  provides a sealing effect thereby excluding forced air from middle ear  14 . As additional fluid is communicated to dilator  9500 , dilator  9500  continues to expand progressively along the length of dilator  9500 , from the distal/lateral end  9501  of dilator  9500  toward the proximal/medial end  9502  of dilator  9500 .  FIG. 18W  shows both proximal end  9502  and distal end  9501  dilated, thereby dilating the Eustachian tube ET. 
     Dilating distal end  9501  first, then progressing toward proximal end  9502 , can be achieved in multiple ways. For instance, distal inflation can be achieved by designing distal end  9501  of dilator  9500  to have a smaller wall thickness compared to proximal end  9502  of dilator  9500 . Alternatively, distal end  9501  could comprise a material with a smaller density than the material of proximal end  9502 , therefore allowing distal end  9501  to inflate first. In yet another alternative, there could be a retractable outer sheath about the exterior of dilator  9500 . The sheath may be initially placed in a distal position and may then be slowly retracted proximally as dilator  9500  is being inflated. Other methods of inflating distal end  9501  of dilator first, then progressing toward proximal end  9502 , will be apparent to a person having ordinary skill in the art in view of the teachings herein. 
       FIG. 18X  shows a cutting (or “scoring”) balloon dilator  1826  according to an alternative embodiment. The balloon dilator  1826  includes cutting members  1828  circumferentially placed around its exterior. In various embodiments, he cutting members  1828  may be wires, sharpened blades, one wire or sharpened blade, small barbs or raised sharp protrusions, or the like. The cutting members may be configured to deliver energy (e.g. RF). In use, the cutting members  1828  expand with the dilator to impinge on the Eustachian tube ET, which allows the dilator to open and stretch along controlled locations.  FIGS. 18Y and 18Z  show before and after representations of a treated Eustachian tube ET. Cutting the Eustachian tube ET along controlled sections  1829  allows the Eustachian tube ET to maintain an expanded shape by at least partially defeating the elastic response of the Eustachian tube ET wall. 
     In an alternative embodiment of the cutting balloon dilator  1826 , the cutting members  1828  may be disposed along only a portion of the circumference of the balloon  1826 . This may be advantageous, because in some cases it may be desirable to score only a portion of a circumference of a Eustachian tube. In some cases, for example, it may be desirable to only score a posterior aspect of the Eustachian tube, perhaps because that portion will react in a desired way to that treatment. Also in various embodiments, the cutting members  1828  may have various suitable heights, sharpness, or other cutting characteristics to provide different levels/depths of cutting. This may be advantageous, because different depths of cutting may be desirable in different Eustachian tubes. 
     In various embodiments of a method for treating a Eustachian tube, a stent may be used to prop open a dilated portion of the Eustachian tube, deliver a drug to the Eustachian tube, or both.  FIG. 19A  shows a stent  1900  according to one embodiment. The stent  1900  is configured as a tapered coil that gradually increases in diameter from a distal portion  1902  to a proximal portion  1904 . The shape of the coil may be similar in scale to the pharyngeal ostium of the Eustachian tube ET, to enhance dilation thereof. The stent  1900  may be constructed from a malleable or shape-memory alloy. Alternatively, the stent  1900  may be constructed from a biodegradable polymer. The stent  1900  may be configured to carry and deliver a substance, such as any of the therapeutic or diagnostic agents disclosed herein, for example, via a biodegradable polymeric coating containing the substance. The polymeric coating may comprise a substance matrix blended with a biodegradable polymer based on lactic or glycolic acid, or on other materials, including poly(dioxanone), poly(trimethylene carbonate) copolymers, and poly (-caprolactone) homopolymers, copolymers polyanhydride, polyorthoester, or polyphosphazene. The stent  1900  may be carried and delivered by a dilation catheter, such as any of the dilation catheters disclosed herein. In use, the stent  1900  maintains mechanical expansion of the opening of the Eustachian tube ET, as shown. Alternatively, the stent  1900  may be configured to apply a minimal force against the Eustachian tube ET wall in order to provide mechanical assistance thereto. The stent may be placed in the Eustachian tube ET permanently or removed at a later time. It should be understood that, due to the open, coil shaped configuration of stent  1900 , stent  1900  may provide a substantially clear path for ventilation through the Eustachian tube ET while stent  1900  is positioned in the Eustachian tube ET. 
       FIG. 19B  shows a stent  1906  according to another embodiment. The stent includes a connecting member  1908  that connects a plurality of expandable tines  1910 . The tines  1910  may be constructed from a malleable or shape-memory alloy. Alternatively, the tines  1910  may be constructed from a biodegradable polymer. The tines  1910  may be configured to carry and deliver a substance, such as any of the therapeutic or diagnostic agents disclosed herein, for example, via a biodegradable polymeric coating containing the substance. The polymeric coating may comprise a substance matrix blended with a biodegradable polymer based on lactic or glycolic acid, or on other materials, including poly(dioxanone), poly(trimethylene carbonate) copolymers, and poly (-caprolactone) homopolymers, copolymers polyanhydride, polyorthoester, or polyphosphazene. The tines  1910  may be carried and delivered by a dilation catheter, such as any of the dilation catheters disclosed herein. The tines  1910  may be configured to radially self-expand upon removal from a constricting shaft, or through force from a balloon. In use, the stent  1906  maintains mechanical expansion of the Eustachian tube ET, as shown. Alternatively, the stent  1906  may be configured to apply a minimal force against the Eustachian tube ET wall in order to provide mechanical assistance thereto. The stent  1906  may be placed in the Eustachian tube ET permanently or removed at a later time. It should be understood that, due to the open configuration of stent  1910 , stent  1910  may provide a substantially clear path for ventilation through the Eustachian tube ET while stent  1910  is positioned in the Eustachian tube ET. 
       FIGS. 19C and 19D  show a stent  1910  according to another embodiment. The stent includes a distal connecting member  1912  and a removable proximal connecting member  1914 , which connect a plurality of expandable tines  1916 . The tines  1916  may be constructed from a shape-memory alloy. Alternatively, the tines  1916  may be constructed from a biodegradable polymer. The tines  1916  may be configured to carry and deliver a substance, such as any of the therapeutic or diagnostic agents disclosed herein, for example, via a biodegradable polymeric coating containing the substance. The polymeric coating may comprise a substance matrix blended with a biodegradable polymer based on lactic or glycolic acid, or on other materials, including poly(dioxanone), poly(trimethylene carbonate) copolymers, and poly (-caprolactone) homopolymers, copolymers polyanhydride, polyorthoester, or polyphosphazene. The tines  1916  may be carried and delivered by a dilation catheter, such as any of the dilation catheters disclosed herein. The tines  1916  may be configured to radially self-expand upon removal from a constricting shaft. In use, the stent  1906  is delivered via a delivery catheter. The removable proximal connecting member  1914  can then be removed to expand the proximal portion of the stent  1910 , and accordingly expand the pharyngeal ostium of the Eustachian tube ET. Once in place, the stent  1906  maintains mechanical expansion of the Eustachian tube ET. Alternatively, the tines  1916  may be configured to apply a minimal force against the Eustachian tube ET wall in order to provide mechanical assistance thereto. The stent  1910  may be placed in the Eustachian tube ET permanently or removed at a later time. It should be understood that, due to the open configuration of stent  1910 , stent  1910  may provide a substantially clear path for ventilation through the Eustachian tube ET while stent  1910  is positioned in the Eustachian tube ET. 
       FIGS. 20A, 20B and 20C  show distal configurations of the guide catheter  1600  according to various embodiments. The distal tips shown can be configured to enter the Eustachian tube ET in order to enable other devices to advance therein.  FIG. 20A  shows a beveled tip  2002 , which allows easier entry into the Eustachian tube ET via a reduced leading edge.  FIG. 20B  shows a tapered tip  2004 , which allows easier entry into the Eustachian tube ET via a reduced leading edge.  FIG. 20C  shows a bulbous tip  2006 , which enables the guide catheter  1600  to seal the Eustachian tube ET via an increased sealing area. The tips may be constructed from a flexible material, such as silicone or rubber, which provides good sealing ability with the Eustachian tube ET. In use, the tips can seal the Eustachian tube ET for therapies such as pressurization, suction and/or the application of a substance to the Eustachian tube ET. 
       FIGS. 21A and 21B  show an insert  2100  according to one embodiment. The insert includes a central elongate shaft  2102  with a plurality of braces  2104  circumferentially extending therefrom. Each brace  2104  is connected to an outer member  2106 , which is rounded for placement against the Eustachian tube ET. The insert  2100  as shown includes three triangulated braces  2104 , however, two or more braces  2104  may be used in alternative embodiments. The insert  2100  may be constructed from a flexible polymer extruded from a die. Alternatively, the insert  2100  may be constructed from a biodegradable polymer. The outer members  2106  may be configured to carry and deliver a substance, such as any of the therapeutic or diagnostic agents disclosed herein. The insert  2100  may be carried and delivered by a dilation catheter, such as any of the dilation catheters disclosed herein. The insert  2100  may be configured to self-expand upon removal from a constricting shaft. In use, the stent  1906  is delivered via a delivery catheter. Once in place, the insert  2100  maintains mechanical expansion of the Eustachian tube ET, as shown in  FIG. 21B . The insert  2100  provides and maintains open spaces  2108  in the Eustachian tube ET to maintain pressure equalization therein. The insert  2100  may be placed in the Eustachian tube ET permanently or removed at a later time. It should be understood that, due to the open configuration provided by open spaces  2108  of insert  2100 , insert  2100  may provide a substantially clear path for ventilation through the Eustachian tube ET while stent  1910  is positioned in the Eustachian tube ET. 
       FIG. 22A  shows a string insert  2200  according to one embodiment. The string insert  2200  may be an elongate alloy or polymer string configured to carry and deliver a substance to the Eustachian tube ET, such as any of the therapeutic or diagnostic agents described herein. The string insert  2200  may be a biodegradable polymer based on lactic or glycolic acid, or on other materials, including poly(dioxanone), poly(trimethylene carbonate) copolymers, and poly (-caprolactone) homopolymers, copolymers polyanhydride, polyorthoester, or polyphosphazene. The string insert may be flexible to conform to the passage of the Eustachian tube ET. The string insert  2200  can be made from several strings in a braided configuration. The string insert can include a proximal loop  2201  to aid in removal from the Eustachian tube ET. 
       FIGS. 22B, 22C and 22D  show delivery catheters for delivering the string insert  2200  to a Eustachian tube ET, according to various embodiments. Delivery catheter  2202  is configured as a shaft and includes a snare  2204  for externally holding the string insert  2200 . The delivery catheter  2202  can be configured to be slid over the guidewire  1604 . In use, the snare  2204  may be actuated to release tension on the string insert  2200  and allow the removal thereof from the delivery catheter  2202 . 
     Delivery catheter  2204  is configured as a shaft which externally holds the string insert  2200 , with a distal portion of the string insert  2200  being internally located. A slidable cutting member  2206  is moveably housed within the delivery catheter  2204 . The delivery catheter  2204  can be configured to slide over the guidewire  1604 . In use, the slidable cutting member  2206  moves in a distal direction to cut string insert  2200  for detachment from the delivery catheter  2204 . 
     Delivery catheter  2208  is configured as a shaft which externally holds the string insert  2200  on an external surface of the delivery catheter  2208 . The delivery catheter  2208  can be configured to slide over the guidewire  1604 . A connection  2210  between the delivery catheter  2208  and the string insert  2200  can be electrically fused. In use, the connection  2210  breaks when a suitable electrical current is passed therethrough. 
       FIGS. 22E and 22F  show the string insert  2200  in use, according to one embodiment. The string insert  2200  is delivered via a delivery catheter  2212  and the guide catheter  1600 . The guidewire  1604  may also be used to assist delivery. The delivery catheter  2212  may be any of the delivery catheters described above. Once the string insert  2200  is placed within the Eustachian tube ET, it can deliver a substance over a sustained period of time. The string insert  2200  may be left in the Eustachian tube ET permanently or removed at a later time. 
     As mentioned previously, any implantable embodiment described herein, such as but not limited to those described in  FIGS. 21 and 22 , may optionally include one or more anchoring members for anchoring the implant in the Eustachian tube or the nasal cavity. Such anchoring members help prevent unwanted migration of an implant out of the Eustachian tube and may include, for example, a suture loop, barb or clip. 
     In various alternative embodiments, any of a number of different endoscopes may be included as part of the methods and systems described above. For example, a standard ENT endoscope may be used in some embodiments—either a zero degree endoscope, an angled endoscope or a combination of both. In another embodiment, a variable degree of view endoscope, such as a swing prism endoscope, may be used. In still another embodiment, a flexible endoscope such as a fiber optic or CMOS scope may be used. 
     In some embodiments, an endoscope may be attached to or incorporated into a dilation catheter (or other treatment catheter) or a guide catheter.  FIGS. 23A-23C  show two embodiments of endoscopes attached to guide catheters.  FIG. 23A  shows a guide catheter  2300  disposed in a nasal cavity NC with its distal end near a Eustachian tube ET. The guide catheter  2300  includes a side-mounted endoscope channel  2302  through which an endoscope such as a flexible fiberscope may be advanced or permanently placed.  FIG. 23B  is a cross-sectional, end-on view of the guide catheter  2300 , which includes an instrument channel  2304  and the endoscope channel  2302 . The endoscope channel  2302  may include optical fibers (or alternatively a chip) in a central portion  2306  and illumination fibers in an outer portion  2308 , or vice versa.  FIG. 23C  is a cross-sectional view of alternative embodiment of a guide catheter  2310 , which also has an instrument channel  2312  but additionally has two side channels comprising a first channel  2314  for optical fibers or a chip and a second channel  2316  for illumination fibers (or vice versa). In various embodiments, any suitable combination and placement of channels may be used. In an alternative embodiment, illumination fibers and/or a fiber optic scope may be embedded into a wall of a guide catheter. 
       FIGS. 24A-24C  demonstrate two alternative embodiments, in which an endoscope is incorporated into a balloon catheter. As shown in  FIG. 24A , a balloon catheter  2400  may generally include a shaft  2402  and a balloon  2404 .  FIG. 24B  shows the balloon catheter  2400  in cross-section from the perspective of the line A-A in  FIG. 24A . In this embodiment, the outer ring is the balloon  2404 , the middle ring  2406  is a channel through which illumination fibers pass, and the inner circle  2408  is a channel through which visualization fibers or a chip pass. In an alternative embodiment, shown in  FIG. 24C , a balloon catheter  2410  may include an outer balloon  2414  surrounding a channel  2416  for passage of illumination fibers. Within the channel  2416  also reside a malleable support member  2418  (such as a wire or the like) and an inner channel  2412  through which the visualization fibers or chip pass. In various embodiments, any combination and configuration of channels may be used. 
     In yet another alternative embodiment (not pictured), any of the devices described herein may be coupled with an endoscope using a sheath, some of which are known in the art and some of which may be invented in the future. The sheath may be disposable and may cover a portion of any suitable endoscope, such as but not limited to a standard endoscope used by ENT physicians, a variable degree of view endoscope, an angled scope, or the like. The sheath may fit over the endoscope (or a portion of the endoscope) and include a side channel through which one or more working devices, such as a guide catheter, balloon dilation catheter, other treatment or diagnostic catheter, or the like may pass. 
     Referring now to  FIG. 25 , in one embodiment a Eustachian tube access guide  2500  may include a hub  2502 , a proximal shaft portion  2510 , and a distal shaft portion  2512 . The hub  2502  may include a stop  2504  on the proximal end, a suction port  2506  for connecting a source of suction such as a suction tube (not shown), and a finger hole  2508  for applying a finger to apply suction through the device  2500 . The distal shaft portion  2512  may include a bend  2516  and a distal tip  2514 . In one embodiment, the Eustachian tube access guide  2500  may be configured and/or manufactured similarly to the Relieva Flex.™. Sinus Guide Catheter (Acclarent, Inc., Menlo Park, Calif.). 
     The access guide  2500  may have any suitable length, diameter and angle of bend. For example, in various embodiments, the access guide  2500  may have an angle of between about 0 degrees and about 180 degrees, and more preferably between about 30 degrees and about 90 degrees. The proximal shaft portion  2510  may be made of a hypotube, the distal shaft portion  2512  may be made of Nylon, and the distal tip  2514  may be made of Pebax in one embodiment. In various embodiments, the distal portion  2512  may be between about 4 cm and about 8 cm and more preferably about 6 cm, and the proximal portion  2510  may be between about 5 cm and about 15 cm, and more preferably between about 8 cm and about 12 cm. 
     Referring now to  FIG. 26 , a balloon dilation catheter  2600  for dilating a Eustachian tube may in some embodiments include a proximal hub  2602 , including a finger hold  2603 , a shaft  2604  and a balloon  2606 . The balloon dilation catheter  2600  may have many of the same features, dimensions and other properties of the Relieva Solo Pro.™. Sinus Balloon Catheter or the Relieva Solo.™. Sinus Balloon Catheter (Acclarent, Inc., Menlo Park, Calif.). In some embodiments, one or more feature, dimension or the like of such catheters may be altered to facilitate use of the balloon catheter  2600  in a Eustachian tube. 
     With reference now to  FIG. 27 , in one embodiment a system for dilating a Eustachian tube  2700  may include a guide device  2710  and a balloon dilation catheter  2720 . The guide device  2710  may have any of the features or characteristics discussed in relation to embodiments described above. In addition, the guide device  2710  may include a handle  2712  having finger holds  2714 . The handle  2710  may be coupled with a shaft  2716 , and the balloon catheter  2720  may pass through the handle  2712  and the shaft  2716 . 
     Referring now to  FIGS. 28A-28D , in one embodiment a balloon dilation catheter  2800  ( FIG. 28A ) for dilating a Eustachian tube may be used with a stylet  2810  ( FIG. 28B ) having a curved portion  2812  and a handle  2814 . As shown in  FIG. 28C , when the stylet  2810  is advanced into the balloon catheter  2800 , the stylet  2810  has sufficient rigidity to retain approximately its original shape, thus conferring the curve of the curved portion  2812  onto the balloon catheter  2800 . As shown in  FIG. 28D , by turning the handle  2814 , the balloon catheter  2800  may be steered, as the curved portion  2812  of the stylet  2810  turns the distal portion of the balloon catheter  2800  in another direction. This is but one example of ways in which a balloon catheter  2800  may be steered in various embodiments. 
     In another embodiment, and with reference now to  FIGS. 29A and 29B , a balloon dilation device  2900  may include a telescoping shaft  2902  and an inflatable balloon portion  2904 . As shown in  FIG. 29A , in one configuration the telescoping shaft  2902  may be lengthened to advance the balloon portion  2904  into a Eustachian tube. As shown in  FIG. 29B , in another configuration the telescoping shaft  2902  may be shortened to retract the balloon portion  2904  and/or for initially advancing the device  2900  into the nasal cavity. This embodiment is but one example of ways in which a dilation device may be advanced into a nasal cavity and subsequently a Eustachian tube to dilate the Eustachian tube. 
     Various examples herein include dilation instruments that rely on inflation of a balloon in order to provide dilation of the Eustachian tube ET (or some other anatomical passageway). However, it should be understood that various other kinds of instruments may be used to provide dilation of the Eustachian tube ET (or some other anatomical passageway). Such alternative instruments may rely on mechanical expansion of a mechanism in order to provide dilation, in addition to or in lieu of relying on inflation of a balloon or other inflatable member in order to provide dilation. By way of example only, mechanical dilation may be provided in accordance with at least some of the teachings of U.S. patent application Ser. No. 14/658,432, entitled “Mechanical Dilation of the Ostia of Paranasal Sinuses and Other Passageways of the Ear, Nose and Throat,” filed Mar. 16, 2015, the disclosure of which is incorporated by reference herein. Other suitable ways in which mechanical dilation may be provided will be apparent to those of ordinary skill in the art in view of the teachings herein. 
       FIG. 30-31  show an exemplary guidewire  50  that can be used in conjunction with the procedures described above. Guidewire  50  comprises a coil  52  positioned about a core wire  54 . An illumination fiber  56  extends along the interior of core wire  54  and terminates in an atraumatic lens  58 . A connector  55  at the proximal end of guidewire  50  enables optical coupling between illumination fiber  56  and a light source. Illumination fiber  56  may comprise one or more optical fibers. Lens  58  is configured to project light when illumination fiber  56  is illuminated by the light source, such that illumination fiber  56  transmits light from the light source to the lens  58 . In some versions, the distal end of guidewire  50  is more flexible than the proximal end of guidewire  50 . By way of example only, guidewire  50  may be configured in accordance with at least some of the teachings of U.S. Pub. No. 2012/0078118, the disclosure of which is incorporated by reference herein. In some versions, guidewire  50  is configured similar to the Relieva Luma Sentry™ Sinus Illumination System by Acclarent, Inc. of Menlo Park, Calif. Other suitable forms that guidewire  50  may take will be apparent to those of ordinary skill in the art in view of the teachings herein. 
     In some circumstances, particularly when accessing the Eustachian tube ET, it might be beneficial to prevent guidewire  50  from passing through to the Isthmus of the Eustachian tube ET, thereby preventing guidewire  50  from entering middle ear  14  and potentially causing damage. This may be addressed by the exemplary alternative guidewire  51  shown in  FIGS. 32-33 . Guidewire  51  is similar to guidewire  50  in every way except for the addition of distal tip  9700 . Distal tip  9700  is sized in such a way to stop guidewire  51  at the Isthmus before it advances further to middle ear  14 . In the present example, the outer diameter of distal tip  9700  is about 2 mm. Alternatively, any other suitable outer diameter may be used. Distal tip  9700  comprises a channel  9702  in order to allow light projected by lens  58  to illuminate the Eustachian tube ET. The light illuminated through channel  9702  into Eustachian tube ET may act as an indicator that the Eustachian tube ET has been sufficiently dilated by transillumination of the tympanic membrane. Additionally or alternatively, distal tip  9700  can be made of material  9701  that is optically transmissive (e.g., transparent or translucent plastic or glass, etc.) such that material  9701  may itself illuminate when light is communicated through illumination fiber  56  and lens  58 . 
     In any of the methods described herein, the operator may first pierce or perforate the eardrum  22  in order to provide a temporary ventilation path through the ear canal  20  via the middle ear  14 . For instance, the operator may drive a needle (e.g., as shown in  FIG. 4 ) or other piercing instrument through the eardrum  22  before inserting a dilator into the Eustachian tube ET  26 . Alternatively, the operator may first insert the dilator into the Eustachian tube ET  26 , then pierce the eardrum  22  before expanding the dilator. In any case, the opening formed through the eardrum  22  may be large enough to allow air to escape from the middle ear  14  via the ear canal  20  during insertion of the dilator in the Eustachian tube ET  26  and/or during expansion of the dilator in the Eustachian tube ET  26 . However, the opening formed through the eardrum  22  may be small enough such that the opening may heal on its own without, requiring any kind of adhesives or sutures, etc., after the dilation process is complete. Various suitable ways in which the eardrum  22  may be pierced before insertion of the dilator in the Eustachian tube ET  26  or before expansion of the dilator in the Eustachian tube ET  26  will be apparent to those of ordinary skill in the art in view of the teachings herein. 
     The present invention may be embodied in other specific forms without departing from the essential characteristics thereof. These other embodiments are intended to be included within the scope of the present invention, which is set forth in the following claims.