Abstract:
Devices and methods are disclosed for creating passages in tissue and detecting blood vessels in and around the passages. The devices may be used to create opening in tissue without removing a sensing assembly from the tissue. The devices herein may be used for altering gaseous flow within a lung to improve the expiration cycle of an individual, particularly individuals having Chronic Obstructive Pulmonary Disease (COPD). In addition, the devices may be used to sample tissue during biopsy or other medical procedures where perforating a blood vessel could result in injury to a patient.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Application No. PCT/US2007/084330, filed Nov. 9, 2007 which claims priority to U.S. Provisional Application No. 60/867,076, filed Nov. 22, 2006; both applications are incorporated herein by reference in their entireties. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention is directed to devices for sensing movement within tissue, and then creating passages in the tissue. In one variation, sensing movement may comprise sensing for the presence or absence of blood vessels. Variations may include further detecting for these blood vessels in the passages created by the device. 
       BACKGROUND OF THE INVENTION 
       [0003]    It was found that creation of collateral channels in COPD patients allowed expired air to pass out of the lungs and decompressed hyper-inflated lungs. Such methods and devices for creating and maintaining collateral channels are discussed in U.S. Pat. No. 6,692,494; U.S. patent application Ser. Nos. 09/947,144, 09/946,706, and 09/947,126 all filed on Sep. 4, 2001; US patent application No. filed on Sep. 4, 2002; U.S. patent application Ser. No. 11/335,263, filed on Jan. 18, 2006; Attorney Docket number BRON-N-E004.05-US, U.S. patent application Ser. No. ______ and filed on Nov. 22, 2006: each of which is incorporated by reference herein in its entirety. 
         [0004]    The creation of these channels also seems to overcome the shortcomings associated with bronchodilator drugs and lung volume reduction surgery. Placement of an implant within the channel further increased the duration of the treatment. 
         [0005]    However, because creation of the opening/channel is typically performed within the airway under bronchoscopic observation, care must be taken so as not to rupture a pulmonary vessel that lies beneath or outside of the airway wall. The need to avoid rupturing vessels that may be hidden by the airway walls is also evident when a surgeon attempts to obtain a biopsy sample from within the bronchial tree. In addition, because the location of the pulmonary vessels varies between patients, care must also be taken when working within the channel or biopsy site. For instance, although a channel may be created without puncturing a blood vessel, the subsequent dilation, insertion of an implant, and/or removal of biopsy material may perforate vessels that were otherwise undetected during the creation of the channel. 
         [0006]    The problem is compounded when accounting for the tidal motion of lungs. For example, because the target site moves due to the tidal motion of the lungs (as a result of the mechanics of breathing), it is difficult to visually identify an area that was previously scanned unless the scanning device remains relatively stationary against the tissue. Moreover, the difficulty increases when considering that the procedure takes place through the camera of a bronchoscope or endoscope. 
         [0007]    In view of the above, a need remains to increase the safety when creating openings in tissue so as not to rupture a blood vessel. Such a device may have applications outside of the lung in any situation where there is a need to locate blood vessels or other fluid carrying vessels prior or during creation of an opening in the tissue. 
       SUMMARY OF THE INVENTION 
       [0008]    The invention relates to creation of passages and/or removal of tissue while allowing sensing of blood vessels that may be in or around the area of the passage. Although specific reference is made to use of the subject invention within the lungs, it is noted that the invention may also be used within various other parts of the body that have a need for such safety measures. 
         [0009]    The device allows for sensing blood vessels in tissue, and allows for creation of a passage or opening without moving the sensing element. The device includes a catheter member having a near end, a far end, and a lumen extending therethrough, a dilation member within the lumen and having a shaft, the shaft having a distal tip and a non-distensible expandable member adjacent to the distal tip, the dilation member being slidably located within the catheter member, a sensing assembly located at the far end of the catheter member, and where the non-distensible expandable member is moveably located within the lumen independent of the sensing assembly, such that when the sensing assembly contacts tissue, the dilation member may be advanced out of the catheter member and into the tissue without removing the sensing member from the tissue. 
         [0010]    The catheter member can be a tubular member as commonly used in medical device applications. Accordingly, the catheter member can be a polymeric tube or a reinforced polymeric tube. As described herein, it may have one or lumens to accommodate the variations of the devices within this disclosure. 
         [0011]    The dilation member is typically used to dilate the opening created by the device. As such it may be a distensible balloon or a non-distensible balloon. The advantages of each are discussed below. Variations of the device include mechanical expandable members such as baskets or other such members. 
         [0012]    The sensing assembly is used to scan the tissue to minimize causing undesirable injury to the patient. As discussed below, any number of sensing modes may be incorporated into the device. However, it was found that Doppler ultrasound transducer assemblies perform acceptably when sensing for blood vessels within tissue. In certain variations, the sensing assembly may be configured to puncture the tissue and create the opening. However, in other variations, the sensing assembly will have a blunted tip to minimize undesirable tissue damage. 
         [0013]    In variations of the device, the sensing assembly is offset from an axis of the catheter and/or dilation assembly. Doing so improves the ability of the sensing assembly to contact tissue surfaces when the device is advanced along body conduits. In addition, this offset feature improves the ability to see the tip of the sensing assembly when the device is used with a scope type device. 
         [0014]    The invention further includes methods of treating tissue, where the method includes selecting an area in the tissue for treatment, advancing a device into the lung to a tissue site, where the device includes a sensing assembly affixed to a catheter and a dilation assembly located within the catheter, scanning the tissue site with the sensing assembly for the presence or absence of blood vessels, creating an opening with the device without removing the sensing assembly from the tissue site, and dilating the opening with the dilation assembly. 
         [0015]    The methods may include treating tissue to assist in decompressing hyper inflated lung tissue. Alternatively, the methods may include scanning of tissue during a biopsy or other medical procedures where perforating a blood vessel could result in injury to a patient. 
         [0016]    The selecting step may be performed with direct visual imaging from the scope type device and/or may be performed with various types of non-invasive imaging equipment such as: x-ray, acoustic imaging, MRI, PET, computed tomography (CT) scans or other such imaging. 
         [0017]    The step of creating the opening with the device may include using the dilation assembly or the sensing assembly to create an opening at the treatment site or adjacent to the treatment site (but within an acceptable range so that the scanning covers the tissue being penetrated). 
         [0018]    In certain variations, the sensing assembly may also be inserted into the opening (prior to or after dilation) to ensure that a blood vessel or other organ was not missed when scanning the surface of the tissue. 
         [0019]    As noted herein, one variation of the device permits scanning the tissue site by placing the sensing assembly in contact with the tissue site. However, various sensing assemblies may permit non-contact scanning. Regardless of whether the sensing tip contacts the tissue, creation of the opening may be performed without significant movement of the scanning assembly. Such a benefit is apparent as medical practitioners may lose track of the scanned tissue if they are required to substitute or move the scanning assembly to create an opening. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIGS. 1A-1C  illustrate various states of the natural airways and the blood-gas interface. 
           [0021]      FIG. 1D  illustrates a schematic of a lung demonstrating a principle of the effect of collateral channels placed therein. 
           [0022]      FIG. 2A  shows a variation of a system as described herein. 
           [0023]      FIG. 2B  shows a far end of a catheter member with a dilation member in an actuated state. 
           [0024]      FIGS. 3A-3F  show variations of the ends of devices. 
           [0025]      FIGS. 4A-4C  show various cross sectional views of devices and the expandable member being attached to a dilation member. 
           [0026]      FIG. 4D  illustrates a variation of a catheter member having dual lumens of varying sizes to accommodate the distal end of the dilation member. 
           [0027]      FIGS. 5A-5B  illustrate a non-exhaustive sample of variations of transducer assemblies. 
           [0028]      FIGS. 6A-6D , illustrate possible variations of optional tips for use with the transducer assembly. 
           [0029]      FIGS. 7A-7D  illustrates examples of using the device to scan, create and dilate an opening in tissue. 
           [0030]      FIG. 7E  illustrates an optional step of scanning the opening before or after dilation of the opening. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]      FIG. 1A  shows a simplified illustration of a natural airway  100  which eventually branches to a blood gas interface  102 .  FIG. 1B  illustrates an airway  100  and blood gas interface  102  in an individual having COPD. The obstructions  104  (e.g., excessive mucus resulting from COPD, see above) impair the passage of gas between the airways  100  and the interface  102 .  FIG. 1C  illustrates a portion of an emphysematous lung where the blood gas interface  102  expands due to the loss of the interface walls  106  which have deteriorated due to a bio-chemical breakdown of the walls  106 . Also depicted is a constriction  108  of the airway  100 . It is generally understood that there is usually a combination of the phenomena depicted in  FIGS. 1A-1C . More usually, the states of the lung depicted in  FIGS. 1B and 1C  are often found in the same lung. 
         [0032]    As will be explained in greater detail below, the production and maintenance of collateral openings or channels through airway walls permits expired air to pass directly out of the lung tissue and into the airways to ultimately facilitate exchange of oxygen into the blood and/or decompress hyper inflated lungs. The term ‘lung tissue’ is intended to include the tissue involved with gas exchange, including but not limited to, gas exchange membranes, alveolar walls, parenchyma, airway walls and/or other such tissue. To accomplish the exchange of oxygen, the collateral channels allow fluid communication between an airway and lung tissue. Therefore, gaseous flow is improved within the lung by altering or redirecting the gaseous flow within the lung, or entirely within the lung. 
         [0033]      FIG. 1D  illustrates a schematic of a lung  118  to demonstrate a benefit of the production and maintenance of collateral openings or channels through airway walls. As shown, a collateral channel  112  (located in an airway wall  110 ) places lung tissue  116  in fluid communication with airways  100  allowing expired air to directly pass out of the airways  100 . The term channel is intended to include an opening, cut, slit, tear, puncture, or any other conceivable artificially created opening. As shown, constricted airways  108  may ordinarily prevent air from exiting the lung tissue  116 . In the example illustrated in  FIG. 1D , there is no implanted structure placed in the collateral channel  112 . However, conduits or implants  119  may be placed in the collateral channels  112  to assist in maintaining the patency of the collateral channels  112 . Examples of conduits may be found in the applications discussed above. While there is no limit to the number of collateral channels which may be created, it is preferable that 1 or 2 channels are placed per lobe of the lung. For example, the preferred number of channels is 2-12 channels per individual patient. In current trials, it was found that 1-4 channels placed per lobe of the lung and 4-16 channels per individual patient was preferable. This number may vary on a case by case basis. For instance, in some cases an emphysematous lung may require 3 or more collateral channels in one or more lobes of the lung. 
         [0034]    The present invention includes a device which is able to detect the presence or absence of a blood vessel by placing a front portion of the device in contact with tissue and then create an opening in the tissue without having to remove the device from the tissue. 
         [0035]      FIG. 2A  illustrates a sectional side view of a variation of the inventive system  150 . The system generally includes a device  200  for sensing the presence of blood vessels and creating passages in tissue. The device  200  includes a catheter member  202  and dilation member  204  extending through the catheter member  202 . In the variation shown, the dilation member  204  is shown in an actuated position outside of the catheter member  202 . However, as discussed herein, the dilation member  204  is moveable relative to the catheter member  202  and sensing assembly  206  so that it can be withdrawn relative to the sensing assembly  206  and/or the catheter member  204 . In this variation, the dilation member  204  is coupled to an actuator  194  that is slidably located on a handle  196  at a near end of the catheter  202 . However, in alternate variations, the dilation member may also extend from the near end of the catheter member  202 . In such a case the medical practitioner moves the dilation member  204  relative to the catheter member  202  to insert the dilation member  204  into the tissue. 
         [0036]    Typically, the catheter member  202  is sufficiently flexible and has a length that allows for the far end of the catheter member  202  to reach target sites when the device  150  enters the body through a bronchoscope or endoscope. Some variations of devices described herein can be constructed to be stiff and inflexible. However, for most procedures, the device has sufficient flexibility, column strength and length to access the tissue targeted for treatment within tortuous anatomy (such as those devices intended for use in small airways of the lung). Accordingly, for devices used to create collateral channels within lungs, the length of the device should preferably be between 1.5-5 ft long (preferably 4-5 ft) in order to reach the targeted airways. 
         [0037]    The device  200  may be coupled to a control system  190  that is configured to assist the medical practitioner in detecting whether blood vessels are at or near a particular target site. The system  150  also includes a fluid source  192  for dilation of the tissue after the device creates the openings. The fluid source may be any standard device used to pressurize gas or liquid into an expandable dilation member  212  located at the far end of the device  200 . Although illustrated to be a syringe type device, the fluid source  192  may a compressor type device as well. 
         [0038]    When used, the control system  190  is coupled to a sensing assembly  206  that extends from the far end of the catheter member  202 . The sensing assembly  206  and control system  190  may be any type of unit that confirms the presence or absence of blood vessels. As such, it may be a thermal based system, light based system, ultrasound based system, or Doppler based system. For exemplary purposes, the control system  190  and sensing assembly  206  are discussed herein as being a Doppler ultrasound system. As such, the sensing assembly  206  includes a sensing tip  208  that is coupled to the power supply  190  as is known by those familiar with such systems. For example, the sensing assembly  206  may include any number of conducting members (e.g., wires) extending along the catheter member  202  (either internally or externally to the catheter member  202 ). In any case, these conducting members provide the energy and controls for the sensing assembly  206 . In the case of Doppler ultrasound, the conducting members couple an ultrasound source  190  to the sensing tip  208  that comprises an ultrasound transducer assembly or lens. 
         [0039]    Moreover, variations of the inventive device include conducting members that comprise a series of wires, with one set of wires being coupled to respective poles of the transducer, and any number of additional sets of wires extending through the device. In addition, the sensing assembly  206  may have more than one sensing surface disposed along the portion of the sensing assembly  206  that extend from the device. 
         [0040]    As discussed herein, any conventional sensing type probe may be used to detect the blood vessel. When using Doppler ultrasound to detect the presence of blood vessels within tissue, the ultrasound can operate at any frequency in the ultrasound range but preferably between 2 Mhz-30 Mhz. It is generally known that higher frequencies provide better resolution while lower frequencies offer better penetration of tissue. In the present invention, because location of blood vessels does not require actual imaging, there may be a balance obtained between the need for resolution and for penetration of tissue. Accordingly, an intermediate frequency may be used (e.g., around 8 Mhz). A variation of the invention may include inserting a fluid or gel into the airway to provide a medium for the Doppler sensors to couple to the tissue to detect blood vessels. In those cases where fluid is not inserted, the device may use mucus found within the airway to directly couple the sensor to the wall of the airway. 
         [0041]    As noted above, Doppler ultrasound was found to be an efficient way to identify blood vessels. As such, the control system  190  can be configured to communicate with an analyzing device or control unit adapted to recognize the reflected signal or measure the Doppler shift between the signals. The source signal may be reflected by changes in density between tissues. In such a case, the reflected signal will have the same frequency as the transmitted signal. When the source signal is reflected from blood moving within a vessel, the reflected signal has a different frequency than that of the source signal. This Doppler Effect permits determination of the presence or absence of a blood vessel within tissue. The Doppler system described herein comprises a Doppler ultrasound mode of detection. However, additional variations include transducer assemblies that allows for the observation of the Doppler Effect via light or sound as well. 
         [0042]    Regardless of the mode incorporated by the sensing assembly the system  150  may include a user interface that allows the user to determine the presence or absence of a blood vessel at the target site. Typically, the user interface provides an audible confirmation signal. However, the confirmation signal may be manifested in a variety of ways (e.g., light, graphically via a monitor/computer, etc.) 
         [0043]    Although depicted as being external to the device, it is contemplated that the control system  190  may alternatively be incorporated into the device  200 . Moreover, the system  150  may incorporate any number of connectors or fitting that allow for either permanent or detachable connections of the fluid source, control system and/or any other auxiliary systems used with the system  150 . 
         [0044]      FIG. 2B  illustrates an expanded view of the dilation member  204  extending out of the far end of the catheter member  202 . As shown, the dilation member includes a distal tip  210  and an expandable member  212  located adjacent to the tip  210 . In the illustration shown, the tip  210  comprises a sharpened tip. When the tip  210  comprises such a tissue piercing configuration, the tip  210  is able to penetrate soft tissue or other composite type tissue (e.g., that of an airway wall). Such a configuration may include a stainless steel thin walled tubing such as a hypo-tube, cannula tubing such as that used for needles, solid sharpened mandrel, double beveled needle tip, etc. located at a far end of a shaft  214  of the dilation member  204 . The tip  210  described herein will be sharp or have a sufficiently small surface area such that insertion of the tip  210  through tissue occurs by advancement of the dilation member  210  (or a component thereof). It is contemplated that, where possible, any of the tissue piercing tips described herein may be incorporated into any of the variations described herein. In alternate variations, the tip  210  may be rounded or blunted. Regardless, the tip  210  is configured to facilitate entry of the expandable member  212  into tissue for dilation of the tissue (whether the opening is created by the tip  210  or the sensing assembly  206 ). 
         [0045]      FIG. 2B  also illustrates the dilation member  204  having an expandable member  212 . Although the expandable member  212  is shown as being a balloon, alternate expandable members (such as those that allow for mechanical dilation such as a basket, a dilator, etc.) are within the scope of the disclosure. In such a case, the fluid source  192  is naturally replaced with the appropriate actuation mechanism. The use of a balloon  212  allows for controlling pressure during dilation of the passage in tissue created by the tip  210 . 
         [0046]    Variations of the device  200  can be designed for use in tough tissue that is resistant to radial expansion (such as an airway wall). In such variations, the balloon may comprise non-distensible balloon to overcome the toughness of the tissue. Non-distensible balloons are generally made up of relatively inelastic materials consisting of PET, nylons, polyurethanes, polyolefins, PVC, and other crosslinked polymers. Therefore, use of a non-distensible balloon allows for easier expansion of tissue because the non-distensible balloon permits high pressurization (&gt;6 atm). Moreover, non-distensible balloons generally inflate in a uniform shape (radially longitudinally, or both) since the balloon unfolds to assume an expanded shape. In contrast, distensible balloons typically expand in shape when pressurized. In any case it should be noted that distensible and/or non-distensible balloons may be used in the present invention depending upon the application. 
         [0047]    Non-distensible balloons typically occupy a greater mass than distensible balloons because the non-distensible balloon is inelastic and is folded in an unexpanded shape. Therefore, variations of the invention include non-distensible balloons having a working diameter (or diameter in an unexpanded shape) that is close to the diameter of the tip  210  or shaft  214 . This allows insertion of the unexpanded balloon into the opening created by the piercing member. Accordingly, balloons of the present invention may include thin walled balloons, balloons with small distal profiles, balloons with distal ends that are close in actual diameter to the diameter of the piercing member, or balloons that folds into low profile state, or balloons having a combination of these features. 
         [0048]      FIG. 2B  also illustrates markers  216 ,  218  placed on the dilation member  204 . In this variation, markers  216 ,  218  are placed on the distal and proximal ends of the expandable member  204 . However, variations include use of a single marker. The markers  216 ,  218  may be radiopaque, and/or visually apparent. In the latter case, a visually apparent marker permits the medical practitioner to confirm location of the expandable member  212  prior to dilation. The marker  218  located at the proximal end of the expandable member  212  assists the practitioner in determining when the expandable member  212  clears the catheter member  202 . 
         [0049]    The markers  216 ,  218  may be a ring of biocompatible polymer and may be selected to provide contrast so that it may be identified as the medical practitioner views the device through an endoscope or bronchoscope. For example, the bronchoscope will usually contain a light-source that illuminates the target area. Therefore, the markers may be fabricated to reflect or refract the light in a different manner from the remainder of the device. In one variation, the markers may be the same color as the remainder of the device, or partially transparent, or entirely transparent, but is identifiable because the markers reflect or refracts light differently than the remainder of the device. 
         [0050]    The markers may be made using a number of techniques. In one example, the mark is a ring formed of silicone and is white. The polymeric ring may be spun onto the dilation member. In another example the marker is a ring formed of silicone and is black. In another example the mark is a ring formed by suspending gold particulates in a polymer allowing for visual and radiopaque contrast. 
         [0051]    The shape of the marker is not limited to a thin ring. The visualization mark may be large. The markers may, for example, be a white coating disposed on the shaft of the dilation member. It should be noted that variations of the invention include coloring the balloon itself, or other expandable member, to provide contrast like the marker. 
         [0052]      FIGS. 3A to 3B  illustrate various configurations of the far end of the catheter member  202  to illustrate variations of sensing assembly  206  configurations. 
         [0053]      FIG. 3A  shows a variation of a sensing assembly  206  having a segment  211  that extends from within the tip of the dilation member  204 . As discussed herein, in most variations, the sensing tip  208  is fixed and extends a distance beyond the catheter  202  so that the tip  208  may be pressed against tissue to scan for blood vessels or other structures. Once the practitioner locates an acceptable site, the practitioner advances the dilation member to create an opening with the distal tip  210 . Although placing the sensing assembly  208  through the dilation member  204  may offer more precise scanning of the tissue prior to creation of any openings, this construction may be more complicated as the added structure of the sensing assembly  204  may make it more difficult to navigate the catheter member  202  through tortuous anatomy. 
         [0054]      FIGS. 3B-3F  illustrate variations of sensing assemblies  206  in which the segments  211  are offset from a central axis of the catheter member  202 . It is noted that the variation of  FIG. 3A  may also comprise an offset segment  211  construction while remaining within the distal tip of the dilation member. In any case, the offset feature is useful when navigating the device  200  through tortuous anatomy. In one aspect, when the offset feature is outside of the dilation member, it eliminates the need for the segment  211  from extending through the length of the catheter member. All constructions of the offset feature also reduces the chance that the sensing tip  208  will be obscured by the catheter member  202  when viewed by the end of the bronchoscope or endoscope. 
         [0055]      FIG. 3B  illustrates another variation of a sensing assembly  206  extending from the far end of a catheter member  202 . In this variation, the segment  211  of the sensing assembly  206  is affixed within the catheter member  202  but externally to the dilation member  204 . The segment  211  may extend through the length of the catheter member  202  or may be terminated near the far end of the catheter member  202  with the conductive elements (e.g., wires) extending to the control system (not shown). In some variations, the segment  211  extends through the device but the portion extending from the far end of the catheter is stiff/has a sufficient column strength to probe tissue while a remainder of the segment has a lower stiffness/column strength to accommodate flexibility of the device. In any such constructions, the conductive element (or segment portion that extends in the device) does not significantly reduce the ability to navigate the device through tortuous anatomy. 
         [0056]      FIG. 3C  illustrates another variation of a segment  211  of the sensing assembly  206  in which the sensing tip  208  is angled away from a central axis of the catheter member  204 . Such a feature is useful when trying to sense along a wall of a body passage because less articulation of the catheter  202  is required to contact the sensing tip  208  against tissue. 
         [0057]      FIG. 3D  shows another variation of an offset sensing assembly  206 . In this variation, the segment  211  may comprise a tube or similar member that extends along and externally to the length of the catheter member  202 . 
         [0058]      FIG. 3E  illustrates yet another variation of an offset sensing tip. However, in this variation, the catheter member  202  can include an integral projection  220  that extends distally from a first lumen  215 . The projection  220  includes a second lumen  222  through which a sensing assembly (not shown) may be secured. 
         [0059]      FIG. 3F  shows another variation in which a segment  211  of the sensing assembly is inserted into the far end of the catheter member. The segment  211  may have connections for coupling to a control system as described above. In such a variation, the catheter member  202  may be a multi-lumen tube with one or more lumens reserved for the sensing assembly. In addition, the location of the segment  211  may be offset as described above. Alternatively, the segment  211  may be placed in the center of the catheter member  202 . Given this configuration, the lumen for the dilation member (not shown) is offset. 
         [0060]    The degree to which the segment  211  and sensing tip  208  extend from the catheter member  202  may vary depending on the particular application. For example, in certain variations, the sensing tip maybe immediately distal to the end of the catheter member. In alternate variations, the sensing tip may extend as shown in the drawings. Such a construction is useful when the practitioner desires to insert the sensing tip  208  into an opening within the tissue to perform additional scanning. 
         [0061]      FIGS. 4A-4C  illustrate various exemplary constructions of the device  200 . In all cases, for illustrative purposes, the expandable member  212  is shown as being in an expanded state. During insertion of the device into the body, the expandable member  211  can be reduced to fit within the catheter member  212  or to the same size as the catheter member. 
         [0062]      FIG. 4A  shows a cross sectional view of a variation of a device  200  as described herein where the dilation member  204  is actuated. In this variation, the sensing assembly  206  is affixed to an exterior of the catheter member  202  and coupled to the control unit  190  via wires or other conducting members. As shown, the dilation member  204  is affixed to an actuator  194 . However, the dilation member  204  is reinforced with a support member  213  that extends from the distal tip  210  through to the handle portion  196 . To actuate the dilation member  204 , the operator advances the actuator  194  to push a polymeric shaft  214  and the support member  213 . As a result, the support member  213  carries the load and increases the amount of force transferred to the distal tip  210 . In an additional variation, a distal end of the support member  213  may be used without a distal tip  210 . In such a case, the distal end of the support member  213  may be sharpened or otherwise configured to be equivalent to the distal tip  210  of the dilation member  204 . This variation also shows the distal end of the expandable member  212  being coupled to the distal tip  210  and the proximal end being coupled to the shaft  214 . While both ends of the balloon may be constricted to be the same size, the distal end of the balloon may be a smaller size to ease insertion of the tip  210  and distal end of the un-inflated balloon into the tissue. 
         [0063]    The support member may be a flexible mandrel or tube. Alternatively, it may be a braided member that provides flexibility for navigation through tortuous anatomy and column strength for driving the end of the device into tissue. 
         [0064]    The use of a reinforcing or support member  213  provides the device  200  with considerable flexibility to navigate through tortuous anatomy while maintaining greater column strength over a device having a non-reinforced polymer shaft. However, in certain variations, a reinforcing member may be incorporated into the shaft  214 . In alternative variations, no reinforcing member is used. 
         [0065]      FIG. 4A , also illustrates the interior of the expandable member being coupled to the fluid source  192 . The illustration is intended for exemplary purposes as any number of couplings may be employed to fluidly couple the expandable member to the fluid source. 
         [0066]      FIG. 4B  illustrates another variation of a shaft  214  of a dilation member. In this example the catheter member is omitted. As shown, a first lumen  215  fluidly couples the fluid source  192  to the expandable member  212 . A second lumen  222  carries the sensing assembly  206 . In this variation, the sensing assembly  206  is affixed to a catheter member so that the dilation member moves over the sensing assembly  206  to penetrate tissue. As also shown, the first lumen  215  may be sealed with a plug  228  or other occlusion member to prevent fluid from escaping from the device. 
         [0067]      FIG. 4C  shows another variation of a device  200  in which the shaft  214  has a single lumen  215  that couples the fluid source  192  to the expandable member  212 . As with the previous variation, the lumen  215  may be plugged or occluded  228 . The sensing assembly  206  of this variation is located on the catheter member  202 . As noted herein, the coupling between the sensing assembly  206  and the control system  190  may go through the catheter member  202  or through a wall of the catheter member  202 . 
         [0068]      FIG. 4C  also illustrates another aspect in which the device  200  includes a sensor or transducer (as described herein)  213  within the expandable member  212 . As described below, placement of a sensor or transducer  213  within the expandable member  212  permits the ability to perform additional scanning of the tissue prior to placement of any implants. 
         [0069]      FIG. 4D  shows a variation of a device  200  in which two lumens  215  and  222  extend through the catheter member  202 . However, the second lumen  222  has a reduced cross sectional area towards the far end of the catheter  202 . This configuration permits increased clearance for the expandable member  212 . In use, the device  200  creates multiple openings during a single session. Increasing the size of the first lumen  215  provides more clearance for the expandable portion of the dilation member to re-enter the catheter member  202 . 
         [0070]    The devices described above may be constructed from any standard medical grade material. For example, the shafts and catheters may comprise commercially available medical-grade flexible tubing. For example, the elongate member may comprise PTFE, polyimide, polypropylene, or other such engineered polymers such as Hytrel® manufactured by DuPont. 
         [0071]      FIGS. 5A-5B  illustrate a non-exhaustive sample of variations of transducer assemblies  302  configured to reduce an overall size of the assembly. It is noted that the invention may use any type of transducer assembly.  FIG. 5A  illustrates a cross-sectional view of a basic variation of a transducer assembly  302 . The transducer assembly  302  includes at least one transducer  308  (e.g., a piezoelectric transducer.) In this variation, the front surface of the transducer  308  comprises a first pole and the rear surface comprises a second pole. 
         [0072]    The transducer or transducers may comprise a piezo-ceramic crystal (e.g., a Motorola PZT 3203 HD ceramic). In the current invention, a single-crystal piezo (SCP) is preferred, but the invention does not exclude the use of other types of ferroelectric material such as poly-crystalline ceramic piezos, polymer piezos, or polymer composites. The substrate, typically made from piezoelectric single crystals (SCP) or ceramics such as PZT, PLZT, PMN, PMN-PT, also, the crystal may be a multi layer composite of a ceramic piezoelectric material. Piezoelectric polymers such as PVDF may also be used. Micromachined transducers, such as those constructed on the surface of a silicon wafer are also contemplated (e.g., such as those provided by Sensant of San Leandro, CA.) As described herein, the transducer or transducers used may be ceramic pieces coated with a conductive coating, such as gold. Other conductive coatings include sputtered metal, metals, or alloys, such as a member of the Platinum Group of the Periodic Table (Ru, Rh, Pd, Re, Os, Ir, and Pt) or gold. Titanium (Ti) is also especially suitable. The transducer may be further coated with a biocompatible layer such as Parylene or Parylene C. 
         [0073]    The covering  306  of the transducer assembly  302  may contain at least a portion of the transducer  308 . In some variations of the invention, the covering  306  may comprise a conductive material. In such cases the covering  306  itself becomes part of the electrical path to the first pole of the transducer  308 . Use of a conductive covering  306  may require insulating material  313  between the sides of the transducer  308 , thereby permitting a first conductive medium  314  to electrically couple only one pole of the transducer  308  to the covering  306 . 
         [0074]    At least a portion of the front surface of the transducer  308  will be in contact with the conductive medium  314 . The conductive medium  314  permits one of the poles of the transducer  308  to be placed in communication with a conducting member that is ultimately coupled to a power supply. As shown in this example, the conductive medium  314  places the pole of the transducer  308  in electrical communication with the covering  306 . In some variations the conductive medium  314  may coat the entire transducer  308  and covering  306 . Alternatively, the conductive medium  314  may be placed over an area small enough to allow for an electrical path between a conducting member and the respective pole of the transducer  308 . The conductive medium  314  may be any conductive material (e.g., gold, silver, tantalum, copper, chrome, or any bio-compatible conductive material, etc. The material may be coated, deposited, plated, painted, wound, wrapped (e.g., a conductive foil), etc. onto the transducer assembly  302 . 
         [0075]    The transducer assembly  302  depicted in  FIG. 5A  also illustrates conducting members  320 ,  322  electrically coupled to respective poles of the transducer  308 . Optionally, the conducting members  320 ,  322  may be encapsulated within an epoxy  311  located within the covering  306 . The epoxy  311  may extend to the transducer  308  thereby assisting in retaining both the conducting members  320 ,  322  and transducer  308  within the covering. It may also be desirable to maintain a gap  328  between the transducer  308  and any other structure. It is believed that this gap  228  improves the ability of the transducer assembly  302  to generate a signal. 
         [0076]      FIG. 5B  illustrates another variation of a transducer assembly  302 . In this variation, the conductive medium  314  extends over the entire transducer covering  306 . Accordingly, the covering  306  may be made of a non-conducting material (e.g. a polyamide tube, polyetherimide, polycarbonate, etc.) The transducer assembly  302  may further comprise a second tube  316  within the covering  306 . This second tube  316  may be a hypo-tube and may optionally be used to electrically couple one of the conducting members to a pole of the transducer  308 . As shown, the covering  306  may contain a non-conductive epoxy  310  (e.g., Hysol 2039/3561 with Scotchlite glass microspheres B23/500) which secures both the conducting member and the second tube  316  within the covering  306 . This construction may have the further effect of structurally securing the transducer  308  within the assembly  302 . Again, a gap  328  may or may not be adjacent to the transducer to permit displacement of the transducer  308 . 
         [0077]      FIG. 5B  also illustrates the assembly  302  as having a conductive epoxy  312  which encapsulates the alternate conducting member  320 . An example of a conductive epoxy is Bisphenol epoxy resin with silver particulates to enable conductivity. The particulates may be from 70-90% of the resin composition. The resin may then be combined with a hardener (e.g., 100 parts resin per 6 parts hardener.) The conductive epoxy  312  is in electrical communication with the conductive medium  314  allowing for a conductive path from the conducting member  320  to the conductive medium  314 . Accordingly, use of the conductive epoxy  312  secures the conducting member  320  to the assembly  302  while electrically coupling the conducting member  320  to the transducer via the conductive coating  314 . 
         [0078]    Although variations of the transducer assembly include a tip and housing, the invention may omit the transducer covering and other structures not necessary to generate a source signal and receive a reflected signal. Therefore, it is contemplated that the invention may simply have a transducer that is coupled to a controller. 
         [0079]    When used in the devices  200  described herein, the tip  208  of the sensing assembly may comprise the transducer  308  shown above, or the coating  314 . In alternative variations, the tip  208  of the sensing assembly may comprise a tip  304  that is affixed to the transducer assembly  302  and as shown in  FIGS. 6A-6D . 
         [0080]      FIGS. 6A-6D , illustrate possible variations of tips  304  for use with the transducer assembly. It is noted that these variations are provided for illustrative purposes and are not meant to be exhaustive. The tips  304  of the present invention may function simply as a blunting tip (but still passes and receives ultrasound signals) or as a lens to disperse and/or direct the signal over a substantial portion of the outer surface of the tip  304 . When configured to function as a lens, the tip  304  is adapted to disperse and/or direct (e.g., by diffraction) a reflected signal towards the transducer (not shown in  FIGS. 6A-6D ). Accordingly, given the above described configuration, the inventive device  300  will be able to detect vessels with substantially most of the tip  304 . The tip may comprise a signal directing means. 
         [0081]    When configured to function as a lens, the tip  304  is designed such that it interferes and redirects the signals in a desired direction in a manner like a lens. It also may be desirable to place an epoxy between the tip  304  and the transducer. Preferably, the epoxy is thin and applied without air gaps, bubbles or pockets. Also, the density/hardness of the epoxy should provide for transmission of the signal while minimizing any effect or change to the source signal. The configuration of the transducer assembly  302  permits the lens tip  304  to disperse a signal over a substantial portion of its outer surface  244 . The lens tip  304  also is adapted to refract a reflected signal towards the transducer  308 . Accordingly, given the above described configuration, the inventive device will be able to detect vessels with any part or substantially the entire lens tip  304  that contacts tissue. 
         [0082]    Although the tip of the present invention is able to transmit a source signal and receive a reflected signal, the invention is not limited to requiring both functions. For example, the inventive device could be configured to generate a source signal and direct the source signal to an area of interest but a second device or transducer assembly could be used to receive the reflected signal. Accordingly, a separate device could be used to generate the source signal with the inventive device being used to receive the reflected signal. 
         [0083]    The tip  304  may be comprised of materials such as a dimethyl pentene, a methylpentene copolymer (plastic-TPX), aluminum, carbon aerogel, polycarbonate (e.g., Lexan), polystyrene, or etc., any standard material used for ultrasound applications. 
         [0084]    As illustrated in  FIG. 6A , although the front surface  244  of the tip  302  is illustrated as being hemispherical, the tip  304  may have other profiles as well. For example, it is desirable that the tip  304  produce a certain amount of divergence of the signal being passed therethrough. However, depending on a variety of factors (e.g., material, frequency of the signal, etc.) a tip  304  may encounter excessive divergence which is destructive to the outgoing signal. Accordingly, it may be desirable to produce a tip  304  as illustrated in  FIG. 6B  in which a front surface  344  of the tip  304  is substantially flat. The degree of flatness of the tip  304  will often depend upon experimentation to reduce the amount of destructive reflections, thus minimizing excessive divergence due to differences in speed of sound in tip versus tissue. For example, when using a tip that is conducive to an ultrasound signal (e.g., TPX) a rounded tip can be used since there is not excessive divergence of the source signal. Use of a material that is not as conducive to ultrasound requires a flatter tip due to the resulting divergence of the source signal.  FIG. 6C  illustrates another variation of a tip  304  having a rounded front surface  344  but with no projections on the sides of the tip  304 .  FIG. 6D  illustrates a tip  304  with a concave front surface  344 . 
         [0085]    In any case, the tip will be configured to avoid sharp edges that may cause any unintended damage to tissue while the device is being used to determine the presence or absence of a blood vessel. In such a case, for example, the tip may be designed such that it doesn&#39;t have sharp edges, or any sharp edges may be covered by other parts of the device (e.g., the elongate member, an outer sheath, etc.) 
         [0086]    Commonly assigned patent publication nos. US20020128647A1; US20020138074A1; US20030130657A1, and US20050107783A1; disclose additional variations of transducer assemblies and modes of securing such assemblies to the device. The entirety of each of which is incorporated by reference herein. 
         [0087]      FIGS. 7A-7E  illustrates an example of use of the devices described herein. Although the figures show a single variation, it is contemplated that any variation of the device may be substituted. In the illustrated example, the device creates an extra-anatomic passage in the airway wall tissue within a lung. However, it is understood that the device may be used in any part of the body and for any application. For example, variations of the device may be used during a biopsy procedure to scan for blood vessels, and remove a biopsy sample within the tissue piercing member. 
         [0088]      FIG. 7A  illustrates an access device  120  advanced into the airways  100  of a lung. The access device  120  may be a bronchoscope, endoscope, endotracheal tube with or without vision capability, or any type of delivery device. The access device  120  will have at least one lumen or working channel  122 . In the illustrated version, access device  120  includes a light  124  and vision  126  capabilities. In one example, the practitioner uses the access device  120  to locate an approximate site  114  for creation of a collateral channel. For example, location of the site may be accomplished visually, or with additional equipment such as a CT scan to locate areas for treatment. In cases where the access device  120  is a bronchoscope or similar device, the access device  120  is equipped so that the surgeon may observe the site for creation of the collateral channel. In some cases it may be desirable for non-invasive imaging of the procedure. In such cases, the access device  120  as well as the other devices discussed herein, may be configured for detection by the particular non-invasive imaging technique such as fluoroscopy, “real-time” computed tomography scanning, or other technique being used. 
         [0089]      FIG. 7A  also illustrates advancement of a variation of the inventive device  200  through the channel  122  of the access device  120  towards the target site  114 . The medical practitioner then uses the sensing assembly  206  to inspect the target site  114  to determine whether a blood vessel  101  is adjacent to the site. If a blood vessel is detected at or near the site  114 , then another target site may be selected. 
         [0090]      FIG. 7B  shows a magnified view of the sensing assembly  206  of the device  200  being pressed against tissue at the target site  114 . Accordingly, variations of the sensing assembly  206  require sufficient stiffness so that the tissue may be adequately probed. As described above, the system  150  provides the medical practitioner with audio or visual signals so that the practitioner can determine whether it is sufficiently safe to make an opening in the tissue. 
         [0091]      FIG. 7C  illustrates the device  200  after the medical practitioner adequately determines that no blood vessel  101  is adjacent to the site  114 . As show, the practioner advances the dilation member  204  into the tissue. In alternate variations of the device, the sensing assembly may be used to create an opening in tissue. However, separating the tissue piercing Function from the sensing function may offer an added safety feature by preventing inadvertent puncturing of tissue. The illustration also shows another useful feature of the device  200  as the sensing assembly  204  and sensing tip  208  can remain in contact with the tissue as the distal tip  208  of the dilation member  204  advances through tissue. As noted above, this feature is useful in environments where the target tissue moves. 
         [0092]      FIG. 7C  also illustrates the use of distal and proximal markers  216 ,  218  on the device  200 . Although the markers  216 ,  218  are shown to be adjacent to the expandable member  212 , the markers  216 ,  218  may be placed anywhere along the device. However, placement of the markers  216 ,  218  adjacent to the expandable member  212  permits visualization of the markers  216 ,  218  so that the medical practitioner can minimize the chance that the proximal end of the expandable member  212  expands within the catheter member  202  or access device  120 . 
         [0093]      FIG. 7D  illustrates expansion of the expandable member  212 . As noted herein, the expandable member  212  may be a non-distensible balloon when the device is used in the lungs. However, variations of the device include the use of non-distensible balloons as well.  FIG. 7D  also illustrates deformation of the airway  100  wall upon expansion of the member  212 . Accordingly, the sensing assembly  206  may or may not be displaced during this process. Furthermore, as noted above, additional variations of the device may include sensors or transducers within the balloon. In such cases, the balloon&#39;s fluid couples the internal sensor/transducer to the surrounding tissue to perform an additional scan prior to placing any implant within the dilated opening. 
         [0094]      FIG. 7E  illustrates an optional step that can take place after the dilation member  204  creates an opening  112  but before or after dilation of the opening  112 . In this variation, the medical practitioner inserts the tip  208  of the sensing assembly  206  into the opening  112  to scan the area within or behind the airway wall. Accordingly, this feature is available when the size of the sensing tip  208  is less than a size of the tissue piercing member. 
         [0095]    After dilation of the passage, the device may be removed. Alternatively, the expanded passage may be filled with fluid for additional scanning via the transducer assembly. 
         [0096]    In one example of the procedure for placing implants in the airways to decompress hyper-inflated lungs, the medical practitioner selects a target location (usually via a CT scan) then confirms that the sensing assembly is function properly. This confirmation may be performed by placing the probe against a known region of tissue having a blood vessel. Next, the practitioner may scans the target site without knowing where a blood vessel is located. If the practitioner identifies a target site that appears to be free of blood vessels, the practioner may scan the areas around the target site to determine a vessel free region. Then, after selecting a site in the center of the region, the practioner creates the opening with a dilation member and subsequently dilates the opening. Some practitioners may scan in the opening prior to dilation and/or after dilation. Once the practitioner is satisfied that area is free of a blood vessel, the practitioner then inserts the implant. 
         [0097]    A further variation of the invention may include configuring the transducer assembly and/or controller to have different levels of sensitivity. For example, a first level of sensitivity may be used to scan the surface of tissue. Then, after creation of the opening, the second level of sensitivity may be triggered. Such a feature acknowledges that scanning of tissue on, for example, the airway wall may require a different sensitivity than when scanning tissue within the parenchyma of the lung. 
         [0098]    It should be noted that the invention includes kits containing the inventive device with any one or more of the following components, a Doppler ultrasound controller, a conduit as described in one or more of the applications listed above, and a bronchoscope/endoscope. 
         [0099]    In the above explanation of Figs., similar numerals may represent similar features for the different variations of the invention. 
         [0100]    The invention herein is described by examples and a desired way of practicing the invention is described. However, the invention as claimed herein is not limited to that specific description in any manner. Equivalence to the description as hereinafter claimed is considered to be within the scope of protection of this patent. 
         [0101]    The devices of the present invention are configured to locate a target site for creation of a collateral channel in the tissue and to create an opening in tissue. As discussed above, a benefit of this combination feature is that a single device is able to select a target location and then create an opening without having been moved. Although the device is discussed as being primarily used in the lungs, the device is not limited as such and it is contemplated that the invention has utility in other areas as well, specifically in applications in which blood vessels or other structures must be avoided while cutting or removing tissue (one such example is tumor removal). 
         [0102]    The above illustrations are examples of the invention described herein. It is contemplated that combinations of aspects of specific embodiments/variations or combinations of the specific embodiments/variations themselves are within the scope of this disclosure.