Abstract:
An anatomical spacer is provided which includes a bladder expandable from a deflated position to an inflated position. A membrane extends between opposing surfaces of the bladder, and an inflation port is placed in communication with the bladder. The inflation port is configured to receive inflation media to fill the bladder from the deflated position to the inflated position. A method is also provided to deploy the spacer into an anatomical location from a cannula.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S)  
       [0001]     The U.S. patent application claims the priority benefit of U.S. Provisional Patent Application No. 60/649,689, filed Feb. 4, 2005, the entire content of which is incorporated herein. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to expandable implants for the treatment of anatomic disorders, including, but not limited to joint disorders, neurological disorders, or infections, and methods and apparatuses for delivering and removing the same.  
       BACKGROUND OF THE INVENTION  
       [0003]     Bursitis is inflammation of a bursa, a small sac of fluid that cushions and lubricates an area between tendon and bone or around a joint. The inflammation can cause the bursa to swell with fluid. Bursitis can occur anywhere in the body where there is a bursa, usually near a joint. The condition is often painful.  
         [0004]     A tendon is the end part of a muscle that attaches the muscle to the bone. The normally very elastic and soft muscle tapers off at the end to form the dense and stiff tendon. While this density makes the tendon stronger, the lack of elasticity of the tendon and the constant pulling on its attachment to the bone with movement, makes it much more susceptible to a low level of tearing at a microscopic level. This tearing will produce the inflammation and irritation known as tendonitis.  
         [0005]     Rotator cuff disorders are irritations in, or damage to, tendons around the shoulder. These disorders include inflammation of the tendons (tendonitis) or the bursa (bursitis), a calcium buildup in the tendons, or partial or complete tears of the tendon. The rotator cuff is a group of tendons and their related muscles that helps keep the upper arm bone securely placed, or seated, into the socket of the shoulder blade. Rotator cuff disorders are usually caused by a combination of factors, such as normal wear and tear. Age-related degeneration slowly damages the rotator cuff, causing one or more tendons to rub against the bones (impingement). Underneath the acromion (subacromial space) is a bursa, which will get inflamed with shoulder impingement and often becomes the cause of a chronic irritation, decreased range of motion, and loss of strength. Compression caused by bursitis is detrimental to the healing process. If non-surgical treatment has failed to relieve impingement, the abnormally swollen and inflamed bursa is often removed. This involves an invasive and expensive open surgical decompression procedure.  
         [0006]     In addition to the problems that exist with the rotator cuff, the same issues appear with bursitis and tendonitis in other joints of the body. The ability to avoid open surgery for treating these conditions and relieve impingement is desirable for effective repair of joint disorders.  
         [0007]     Accordingly, there exists a need for devices and methods for treating joint disorders that overcome the problems and inadequacies of treatments currently available. Particularly, there is a need for percutaneous modality to deliver implants that effectively provide decompression and relieve the adverse effects of joint disorders. The same need is present for other anatomical related conditions, such as the isolation and treatment of tumors.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention relates to temporary and permanent expandable implants for the mechanical creation and maintenance of spaces in anatomical locations, and methods and apparatuses for delivering the same. The implants generally comprise a compressed form having a size adapted for insertion via a cannula into the prescribed location, and a composition that allows the implant to expand from the compressed form into an expanded form after the implant is inserted. The expanded form of the implant has a configuration that creates and maintains the desired anatomical space. The implant may also include a pharmaceutical element that treats disorders or diseases such as, but not limited to, inflammation and oncological conditions. The pharmaceutical element could be a drug eluding coating or a drug reservoir that permeates through a barrier to the treatment site.  
         [0009]     Various delivery devices can be used to insert the present implants into the area being treated. The devices are adapted to retain the implant while the device is inserted into the desired location, and to controllably release the implant therein.  
         [0010]     Due to the implant possibly being temporary, various retrieval devices can be used to remove the implant from the treatment site. Ideally the implant position, along with design features just superficial the dermis, allow retrieval and removal by a device requiring a small incision, and without the need of imaging equipment.  
         [0011]     In an exemplary embodiment of the invention, a spacer for placement in an anatomical location includes a bladder being expandable from a deflated position to an inflated position, the bladder having at least one pair of opposing surfaces, the opposing surfaces being outer surfaces of the bladder and facing one another; a membrane extending between the opposing surfaces of the bladder; and an inflation port, the inflation port being in communication with the bladder and configured to receive inflation media to fill the bladder from the deflated position to the inflated position.  
         [0012]     In another exemplary embodiment, the spacer includes wires defining an outer surface of the bladder. In yet another exemplary embodiment, the spacer includes at least one holder attached to the bladder, and the at least one holder is coupled to the wires.  
         [0013]     In another exemplary embodiment, the wires are formed of nitinol. In yet another exemplary embodiment the inflation media is radiopaque. In yet another exemplary embodiment, the bladder is formed of polyethylene terephthalate. In yet another exemplary embodiment, the bladder is formed of a permeable material. In yet another exemplary embodiment, the inflation media comprises a medicinal substance.  
         [0014]     In another exemplary embodiment, the bladder has a toroidal shape. In yet another exemplary embodiment, the membrane is formed of an additional bladder configured to elude medicine to the anatomical location.  
         [0015]     In yet another exemplary embodiment, a spacer assembly for placement of a spacer in an anatomical position includes a spacer having a first holder and a second holder, the first holder being located proximally to the second holder, and a tension-compression mechanism having a pull tube and a push tube slidably coupled to one another. The pull tube is coupled to the second holder, and the push tube is coupled to the first holder.  
         [0016]     In yet another exemplary embodiment, the pull tube is releasably coupled to the second holder. In yet another exemplary embodiment, the pull tube is located outside the push tube and includes at least one leg extending to the second holder. In yet another exemplary embodiment, the at least one leg is slidable in a direction of a longitudinal axis of the pull tube within a passage located in the first holder. In yet another exemplary embodiment, the pull tube includes a notch, and the pull tube is rotatable relative to the first holder about the longitudinal axis of the pull tube when the notch is located in the passage.  
         [0017]     In another exemplary embodiment, a method for placement of an anatomical spacer includes placing a spacer inside a cannula. The spacer includes a bladder having at least one pair of opposing surfaces, an inflation port, the inflation port being in communication with the bladder and configured to receive an inflation media, and wires extending from a first holder to a second holder about an outer surface of the spacer. The method also includes retracting the cannula from the spacer at a predetermined site, with the inflation port located subcutaneously.  
         [0018]     In yet another embodiment, the method further includes inflating the bladder with the inflation media from a deflated position to an inflated position. In yet another embodiment, the first holder and the second holder are located on opposite sides of the bladder and are attached thereto, and the method includes moving the first holder closer to the second holder. In yet another exemplary embodiment, a tension-compression mechanism is coupled to the first holder and the second holder, and the method includes actuating the tension-compression mechanism to position the spacer, and removing the tension-compression mechanism from the spacer.  
         [0019]     In another embodiment of the invention, a spacer for placement in an anatomical location includes a helical spring having a toroidal shape; a pliable pouch covering the toroidal shape of the helical spring; and at least one holder coupled to the helical spring. In yet another embodiment, the helical spring is formed of nitinol. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]      FIG. 1  shows an isometric view of a toroidal shaped anatomical spacer in an expanded state according to aspects of the invention.  
         [0021]      FIG. 2  shows an isometric view of a toroidal shaped anatomical spacer with opposing wire supports in an expanded state according to aspects of the invention.  
         [0022]      FIGS. 3A and 3B  show isometric views of an anatomical spacer with opposing wire supports in a folded (compressed) state according to aspects of the invention.  
         [0023]      FIG. 4  shows an isometric view of the anatomical spacer with opposing wire supports in a partially deployed state according to aspects of the invention.  
         [0024]      FIG. 5  shows an isometric view of a pliable pouch with opposing helical wire springs in the expanded state according to aspects of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]     With reference to  FIG. 1 , a anatomical spacer  10 , sometimes called an implant, can temporarily or permanently be implanted in or near a joint to prevent indirect or direct bone to tendon contact, also known as impingement. In one exemplary embodiment, the spacer  10  includes a bladder  12  having a toroidal shape, a membrane  14  tenting across the inner toroidal shaped space, and an inflation port  16  located at a junction of the bladder  12 .  
         [0026]     The bladder  12  is capable of pliable inflation, and could be made from a compressible, yet not stretchable (i.e., non-compliant) material such as polyethylene terephthalate, commonly known as PET. The bladder  12  may be folded similar to an angioplasty balloon, providing reduced profile for insertion down a cannula, as will be described below. An inflation media, formed from any fluid acceptable for implant applications, fills the bladder  12  to perform the function of the spacer, as described below. One possible inflation media is a radiopaque contrast medium to facilitate observation under x-ray imaging. In another embodiment, the bladder  12  is permeable and the inflation media is medicated, thus allowing the medicated inflation media to be released to an implant site to aid in reducing inflammation or other disorders.  
         [0027]     The membrane  14  extends in the inner toroidal shaped space defined by the bladder  12 , and is secured to an outer surface of the bladder  12 . The membrane may be formed from a single sheet as shown in  FIG. 1 . On other embodiments, the membrane is formed from a flexible sock that encapsulates the bladder. The sock may have drug eluding qualities to provide medication to the implant site. The membrane itself may form an independent bladder, the independent bladder having its own dedicated port for filling. The independent bladder may act as a drug reservoir for dispensing of a pharmaceutical element to the implant site.  
         [0028]     The inflation port  16  includes a manifold tube  18  and a septum  20 . The port  16  is capable of receiving a needle for inflation of the bladder  12 , as described below. The manifold tube  18  includes openings for communication of the inside of the manifold tube  18  with the inside of the bladder  12 . The openings in the manifold tube  18  allow the inflation media to enter and inflate the bladder  12 .  
         [0029]     With reference to  FIG. 2 , a pair of opposing wire supports  22  extend around an outer circumference of the bladder  12  to give structural integrity to the implant  10 . The port  16  includes a proximal holder  24  in which the wire supports  22  are held. The proximal holder  24  is secured to the outside of the manifold tube  18  (see  FIG. 1 ), and includes slots  25  into which the opposing wires  22  are inserted and a rim  26  located around the septum. The rim  26  has portions removed which define passages  27 . The passages  27  extend circumferentially around the manifold tube  18 .  
         [0030]     A distal holder  28  in which the wire supports are held is located diametrically opposed to the proximal holder  24 . The distal holder  28  is secured to the bladder  12  and is oriented radially and in line with the port  16 . The distal holder  28  is generally tube shaped, and the wire supports are grasped inside the tube shaped holder. The wire supports  22  extend from an outer end of the second holder  28  before curving back to the outer circumference of the bladder  12 . The wire supports  22  may be fabricated from super elastic nitinol material to prevent permanent deformation when being compressed for insertion.  
         [0031]     With reference to  FIGS. 3A and 3B , the implant is capable of being compressed to a reduced profile for delivery to the implant site from a cannula  30 . In order to fit into the cannula  30 , the bladder  12  (see  FIG. 1 ) may be folded similar to an angioplasty balloon, as is known in the art. The wire supports  22  are flexed to be able to fit into the delivery cannula  30 . A tension-compression mechanism including a pull rod  32  and a push rod  34  is used to control the proximal holder  24  and the distal holder  28  and deploy the spacer  10  (see  FIG. 1 ) at the implant site. The pull rod  32  and the push rod  34  are both generally tube shaped. The pull rod  32  is placed outside the push rod  34 , with a proximal end  36  of the push rod  34  extending proximally from a proximal end  38  of the pull rod  32 . A distal end  40  of the push rod  34  abuts at least one of a proximal end of the manifold tube  18  (see  FIG. 1 ) and the rim  26 .  
         [0032]     The pull rod  32  splits into two legs  42  and  44  (see also  FIG. 4 ) that extend through the passages  27  (see  FIG. 2 ) in the proximal holder  24 . The legs  42  and  44  continue the curved profile of the pull rod  32  and include a notch  46  at a predetermined position, as described below. The legs  42  and  44  extend to the distal holder  28 , and may be releasably coupled thereto.  
         [0033]     The cannula  30  houses the spacer  10  (see  FIGS. 1 and 2 ) during delivery to the implant site. Delivery of the spacer to the implant site is achieved by placement of the cannula  30  in the desired anatomical space by methods known in the art. The cannula  30  is then retracted as an operator holds the position of the proximal holder  24  and the distal holder  28  by holding the pull rod  32  and the push rod  44  in a stable position. The opposing wires  22  are deployed as the pull rod  32  is moved proximally over the stationary push rod  34 , toward the proximal end  36  thereof. The distal end  40  of the push rod  34  bears against the proximal holder  24  and or the proximal end of the manifold tube  18  (see  FIGS. 1 and 2 ), maintaining constant the position of the proximal holder  24 , while the distal holder  28 , coupled to the pull rod  32 , moves proximally closer to the stationary proximal holder  24 . The opposing wires  22  are also deployed as the push rod  34  is moved distally into the stationary pull rod  32 . The second holder  28 , coupled to the stationary pull rod  32 , maintains a constant position as the push rod  34  bears against the proximal holder  24 , moving it toward the stationary distal holder  28 . The inflation port  16  and proximal holder  24 , being located proximally, are the last items from the spacer  10  delivered out of the cannula  30 .  
         [0034]     With reference to  FIG. 4 , the opposing wires  22 , which exert forces on surrounding objects to reach their natural curved state, can provide a displacement force needed to overcome possible obstructions during implantation, assuring that the spacer  10  can reach its intended deployed shape. The tension-compression mechanism can be manipulated to achieve proper positioning and remove anatomical obstructions, using relative movement between the pull rod  32  and the push rod  34 , as described above. The notch  46  is located in the passages  27  (see  FIG. 2 ), indicating that the wires  22  are in the natural state. The pull rod  32  can then be rotated along its longitudinal axis within the passages  27 , releasing the coupling of the pull rod  32  and the distal holder  28 .  
         [0035]     The tension-compression mechanism can then be removed from the implant site as the pull rod  32  is pulled proximally from the passages  27  (see  FIG. 2 ). Using this technique, the proximal holder  24  and the inflation port  16  can be positioned subcutaneously to allow superficial access and removal of the spacer  10 .  
         [0036]     The bladder  12 , shown in a deflated state in  FIG. 4 , is then inflated to effectively create a spacer. The septum  20  is configured for needle penetration and delivery of the inflation media. The inflated bladder  12  (see  FIG. 2 ) would prevent the bone from impinging against the sensitive portion of the tendon.  
         [0037]     Removal of the spacer  10  may be accomplished by a small incision to access the port, needle puncture through the port septum  20 , evacuation of the inflation media, and then complete removal of the deflated bladder.  
         [0038]     With reference to  FIG. 5 , an alternative embodiment spacer  50  includes a pliable pouch  52 , two opposing helical spring members  54 , a distal connector  56 , and a proximal connector  58 . The helical spring members  54  have an axis that follows a half circle, thus effectively creating a toroidal shape. Both of the spring members  54  are attached on each end to one of the connectors  56 ,  58 . The opposing helical spring members  54  could be controlled by the distal connector  16  and proximal connector  17  being operated by a tension-compression mechanism, for example, as the tension-compression mechanism described above. The helical spring members could be fabricated from super elastic nitinol material to prevent permanent deformation when undergoing the extreme tension needed for delivery down a cannula.  
         [0039]     After the implant is in proper position, the tension-compression mechanism would be released and removed. The nitinol helical springs could collapse on their sides when under high loading, yet the collapsed mode would still provide the spacer effect needed to prevent impingement. Removal of the implant may be accomplished by a small incision to retrieve the proximal connector, attachment to a removal tool (which could be same as delivery tool), activation of the tension-compression mechanism to obtain a small profile, and then complete removal of the implant.  
         [0040]     The implant retrieval and removal procedure for all the embodiments might not require imaging equipment, and could possible be performed in a physician office setting. Although the embodiments above refer to a toroidal or “donut shaped” spacer, other shapes that better approximate the particular anatomy being treated are conceivable.  
         [0041]     While the invention has been described in its preferred embodiments, it is to be understood that the words which have been used are words of description and not of limitation. Therefore, changes may be made within the scope of the appended claims without departing from the true spirit and scope of the invention.