Patent Publication Number: US-2003229364-A1

Title: Device for anastomosis in a radical retropubic prostatectomy

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to a device for joining together two hollow body lumens, and more particularly, to a device for anastomosis in a radical retropubic prostatectomy.  
       BACKGROUND OF THE INVENTION  
       [0002] There are many surgical procedures requiring the connection of vessels, hollow organs and other body lumens. While some of these structures are large, and more easily manipulated by the surgeon, other body lumens are smaller and more difficult to manipulate and hold in position while joining ends thereof after, for example, a transectional operation.  
       [0003] Radical retropubic prostatectomy is one type of surgical procedure for patients with localized prostatic carcinoma, and often requires complex and timeconsuming anastomosis. In general, this surgical procedure requires the removal of the prostate gland after severing the gland from the bladder neck and the urethra. It is the attachment of the urethral stump to the bladder neck which is particularly difficult. This difficulty is complicated by the tendency of the urethral stump to retract into adjacent tissue. As a result, considerable time and effort must be extended to re-expose the urethra stump and begin the anastomosis procedure. Further complicating this procedure is the fact that the urethral stump is hidden beneath the pubic bone thus requiring that the surgeon work at a difficult angle and in positions that are uncomfortable and limiting.  
       [0004] While there have been some attempts to provide improved devices and methods for anastomosis in radical retropubic prostatectomy, for example, these attempts have not been entirely successful.  
       SUMMARY OF THE INVENTION  
       [0005] In accordance with one aspect of the present invention, an anastomotic device may include a superelastic stent body having a longitudinal cavity that extends from proximal and distal ends of the stent body. Proximal and distal rows of retractable needles having a substantially concave curvature may be circumferentially positioned around the stent body. The device may be configured so that the proximal and distal rows of retractable needles are individually deployable in approximated lumens, such as a urethra and bladder. Once deployed, the proximal and distal rows of retractable needles respectively engage the urethra and bladder.  
       [0006] In accordance with another aspect of the present invention, each of the needles of the proximal and distal rows of retractable needles is positioned at substantially the same distance from adjacent needles.  
       [0007] In another aspect of the present invention, a distance of at least about 1.5 cm separates the proximal and distal rows of retractable needles.  
       [0008] In still yet another aspect of the present invention, the stent body comprises Nitinol alloys.  
       [0009] In another aspect of the present invention, the stent body may be substantially cylindrical.  
       [0010] In yet another aspect of the present invention, the stent body comprises reference markings, half way between the two rows of needles, to facilitate the deployment of the stent body into the urethra and bladder.  
       [0011] In still yet another aspect of the present invention, the proximal and distal rows of retractable needles are permanently affixed to the stent body.  
       [0012] Alternatively, the proximal and distal rows of retractable needles comprise absorbable and/or dissolvable materials.  
       [0013] In yet another aspect of the present invention, the proximal and distal rows of retractable needles each comprise at least four individual needles. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0014] The nature, objects, and advantages of the present invention will become more apparent to those skilled in the art after considering the following detailed description in connection with the accompanying drawings, in which like reference numerals designate like parts throughout, and wherein:  
     [0015]FIG. 1 is a side view of a first embodiment of the expandable stent of the present invention;  
     [0016]FIG. 2 is a cross-sectional view of a stent taken along line  2 - 2  of FIG. 1, showing the spatial relationship of the proximal row of needles relative to the stent body, and one another;  
     [0017]FIG. 3 is a cross-sectional diagram of a typical delivery catheter that may be used to deliver the stent of the present invention to a desired anastomosis site;  
     [0018] FIGS.  4 A-E are cross-sectional diagrams showing relevant deployment operations that may be used to deploy the stent of the present invention, providing anastomosis of a urethra and bladder;  
     [0019] FIGS.  5 A-C are cross-sectional diagrams showing relevant removal operations that may be used to retrieve the stent of the present invention after anastomosis is completed;  
     [0020]FIG. 6 is a side view of an alternative embodiment of the stent of the present invention;  
     [0021]FIG. 7 is a cross-sectional view of a stent taken along line  7 - 7  of FIG. 6, showing the spatial relationship of the proximal row of needles relative to the stent body, and one another;  
     [0022]FIG. 8 is a cross-sectional diagram of an alternative delivery catheter that may be used to deliver the stent of the present invention to a desired anastomosis site; and  
     [0023] FIGS.  9 A-C are cross-sectional diagrams showing relevant deployment operations that may be used to deploy the stent of the present invention, providing anastomosis of a urethra and bladder. 
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT  
     [0024] In the following description of a preferred embodiment, reference is made to the accompanying drawings, which form a part hereof, and which show by way of illustration a specific embodiment of the invention. It is to be understood by those of working skill in this technological field that other embodiments may be utilized, and structural as well as procedural changes may be made without departing from the scope of the present invention.  
     [0025] It is to be understood that the stent device and associated methods of the present invention are applicable to a variety of anastomosis procedures wherein two conduits are to be joined in a manner facilitating fluid flow and patency.  
     [0026] Although several stent devices are shown and discussed with reference to the bladder neck and urethral stump as a matter of convenience, it will be appreciated that slight modifications of the device may make the device applicable to other anastomosis procedures, without the need of inventive faculty.  
     [0027] Expandable Stent  
     [0028] Referring initially to FIG. 1, a side view of a first embodiment of the expandable stent of the present invention is shown and generally designated  10 . As shown, stent  10  includes a stent body  15  having a longitudinal cavity  20  that extends from the proximal and distal ends  25 ,  30  of the stent body  15 . Stent  10  may further include two circumferential rows of retractable needles. In particular, stent  10  is shown having proximal and distal rows of needles  35  and  40  that are positioned, respectively, near the proximal and distal ends  25  and  30  of the stent body  15 .  
     [0029] The stent body  10  is shown having an optional reference marking  45  that may be positioned, for example, at about the mid-point of the stent body. The reference marking  45  may be implemented as a colored or patterned region that contrasts the surrounding stent body  15 . Additionally or alternatively, reference marking  45  may be implemented as ridge, groove, or any other similar spatial identifier. The referenced marking  45  may be used, for example, to facilitate the placement of the stent  10  within a body lumen, which will be described in detail herein.  
     [0030] The row of needles  35  and  40  are typically positioned so there is sufficient distance between these rows to enable the approximation of body lumens. Although the present invention does not rely upon any particular amount of spatial separation between needle rows  35  and  40 , an appropriate distance may be anywhere from about 1.5 cm to about 2.0 cm.  
     [0031] Stent  10  may be fabricated using any of a variety of conventional biocompatible materials and processes. Both non-metals and metals can be used. Memory metals are suitable, as well as materials that are absorbable and dissolvable. For example, stent  10  may be fabricated using any of a variety of superelastic or shape memory metals, alloys, plastics, and the like. Currently, Nitinol alloys comprising a mixture of Nickel and Titanium are frequently used in medical device fabrication, and may be used to fabricate the devices of the present invention. Stent  10  may also be fabricated using non-metal materials such as plastics, polyester, polyolefin, nylon, polyurethane, and the like.  
     [0032] If desired, materials that are absorbable by the body once anastomosis is sufficiently completed may be used. Alternatively, dissolvable materials that can pass through the body, for example with different body fluids such as blood, urine, and the like, may also be used.  
     [0033] Stent  10  may be formed using any of a variety of different geometries and configurations including cylindrical, rectangular, oval, and the like. Stent  10  may also be constructed as a wire-like structure (e.g., Nitinol basket), or as a solid or substantially solid design, as long as fluid flow is not unduly hindered.  
     [0034] Each of the individual needles comprising the needle rows  35  and  40  may be fabricated with most any available material, including any of the above-described materials. According to one embodiment, needle rows  35  and  40  may be permanently affixed to the stent body  15 , such that they remain attached to the stent body  15  before and after deployment in a body lumen. Alternatively, needle rows  35  and  40  may be made with absorbable and/or dissolvable materials, if  20  desired.  
     [0035] The individual needles of needle rows  35  and  40  are shown with a concave design, with each needle row facing the mid-line of the stent body  15 . Typically, the individual needles of rows  35  and  40  are positioned at the same, or substantially the same, distance from one another. This needle arrangement facilitates the placement and retention of stent  10  within a body lumen. However, if desired, a staggered configuration may be used where one or more needles are positioned so that they are closer to, or further away from, the apposing row of needles (not shown).  
     [0036]FIG. 2 is a cross-sectional view of stent  10  taken along line  2 - 2  of FIG. 1, showing the spatial relationship of the proximal row of needles  35  relative to the stent body  15 , and one another. It is to be understood that the distal row of needles  40  may be configured using the same, or different, design used for the proximal row of needles  35 .  
     [0037] Stent  10  is shown with six individual needles comprising the proximal row of needles  35 . Each of the six needles comprising row  35  are shown positioned at equal distances relative to one another. However, this arrangement is not essential and that individual needles may be arranged so that they are closer to, or further away from, adjacent needles. Although about four to six needles are used in each of the row of needles  35  (and row  40 ) of a typical stent device, greater or fewer needles may be used.  
     [0038] Delivery Catheter  
     [0039]FIG. 3 is a cross-sectional diagram of a typical delivery catheter that may be used to deliver the stent of the present invention to a desired anastomosis site. Delivery catheter  50  represents any of a variety of currently available catheters (e.g., Foley catheter).  
     [0040] Delivery catheter  50  is shown having an elongated tube  55  that has a proximal end  60  that remains outside of a patient&#39;s body, and a distal end  65  that is eventually passed through the patient&#39;s urethras and into the bladder. The delivery catheter  50  may be configured with an optional removable end cap  70 , if desired.  
     [0041] Stent  10  is shown positioned within the catheter tube  55  in a non-deployed state. An appropriate device, such as the push rod  75  and handle  80 , may be used to deploy and ultimately recover the stent  10 .  
     [0042] Stent Deployment  
     [0043] FIGS.  4 A-E are cross-sectional diagrams showing relevant deployment operations that may be used to deploy the stent of the present invention, providing anastomosis of a urethra and bladder. For convenience only, the following discussion will reference the anastomosis of a urethra and bladder following a radical retropubic prostatectomy, but it is to be appreciated that the present invention is not so limited and may be utilized in other applications.  
     [0044] To carry stent  10  to the desired anastomosis region, stent  10  may be positioned in its non-deployed state within the delivery catheter  50 . As shown in FIG. 4A, the delivery catheter  50  and stent  10  combination may then be advanced through the urethra  85 . Advancement of the catheter  50  may continue until distal end  65  of the catheter  50  clears the urethra  85  (FIG. 4B). At this point, the surgeon may remove the optional end cap  70 , if necessary.  
     [0045] The catheter  50  may then be further advanced into the bladder  90  (FIG. 4C). Optimally, the positioning of the catheter  50  within the bladder  90  is such that the distal row of needles  40  are contained with the bladder  90 , while the proximal row of needles  35  are outside of the bladder  90 .  
     [0046] To facilitate the positioning of stent  10 , the reference markings  45  on the stent  10  may be used for guidance. For example, reference markings  45  may be located on stent  10  at a position that indicates an optimal or desire depth that stent  10  is to be introduced into the bladder  90 . Alternatively, a transparent catheter  50  may permit a surgeon to identify the proximal and distal rows of needles  35  and  40  and then visually estimate a proper insertion depth.  
     [0047] Regardless of the procedure utilized, proper placement of stent  10  within the bladder  90  is critical to successful anastomosis. Once stent  10  has been properly placed within the bladder  90 , the delivery catheter  50  may be partially retracted, releasing at least a portion of stent  10 , while still containing a remaining portion of stent  10  (FIG. 4D). Specifically, the catheter  50  may be retracted so that the distal rows of needles  40  are deployed, while the proximal rows of needles  35  are still contained with the catheter  50  and remain in an un-deployed state.  
     [0048] Referring still to FIG. 4D, stent  10  is shown partially deployed causing the distal row of needles  40  to be forced in communication with the bladder  90 . Typically, the surgeon may manipulate (translate, rotate, etc.) the stent  10  within the bladder  90  to facilitate the proper engagement of the distal row of needles  40  within the bladder  90 .  
     [0049] Once acceptable placement of stent  10  within the bladder  90  has been achieved, the urethra  85  and bladder  90  may be brought into approximation (FIG. 4E). At this point, the un-deployed portion of stent  10  (proximal row of needles  35 ) may be positioned within the urethra  85 , while the deployed portion of stent  10  (distal row of needles  40 ) is positioned within the bladder  90 . Next, the delivery catheter  50  may again be retracted so that the remaining (un-deployed) portion of stent  10  can be released.  
     [0050] Similar to the deployment of the distal row of needles  40 , the second retraction of the catheter  50  releases the proximal row of needles  35  which are forced into communication with the urethra  85  by the expanding stent  10 . Again, it may be necessary for the surgeon to manipulate (translate, rotate, etc.) stent  10  to facilitate the proper engagement of the proximal row of needles  35  within the urethra  85 . Rod  75  may then be disengaged from the stent  10  and completely retracted along with the delivery catheter  50 . Accordingly, the present invention provides a method and device for the anastomosis of body lumens without the use of sutures, staples or clamps, and is particularly useful for the anastomosis of the urethra and bladder following prostatectomy.  
     [0051] It is to be further understood that the substantially hollow nature of stent  10  permits the introduction of a variety of different surgical tools at any time during or after deployment. Typical devices may include, for example, cystoscopes, resectoscopes, tubes, Foley catheters, artificial sphincters, and the like.  
     [0052] Stent Removal  
     [0053] After a time period, such as for example, thirty days, anastomosis is essentially complete and stent  10  may be removed. Alternatively, it may have already become absorbed by the body or dissolved and passed through the urine.  
     [0054] FIGS.  5 A-C are cross-sectional diagrams showing relevant removal operations that may be used to retrieve the stent of the present invention. FIG. 5A shows stent  10  in the deployed state, and the advancement of the removal catheter  95  into the urethra  85 . The removal catheter  95  may be the same (or different) type of catheter as the delivery catheter. The removal catheter  95  may then be advanced over stent  10 , releasing the proximal and distal rows of needles  35  and  40  from their respective positions within the urethra  85  and bladder  90 . An appropriate device, such as rod  75 , may then engage stent  10  so that the stent and removal catheter  95  may be completely retracted (FIG. 5C).  
     [0055] Although the invention may be implemented using the exemplary stent deployment and removal techniques shown in FIGS.  4 A-E, and  5 A-C, those of ordinary skill in the art will realize no particular stent deployment and retrieval technique or device is required.  
     [0056] Cylindrical Stent Design  
     [0057] Referring now to FIG. 6, a side view of an alternative embodiment of the expandable stent of the present invention is shown and generally designated  200 . Similarly to the stent shown in FIG. 1, stent  200  shown in FIG. 6 comprises a stent body  205  having a longitudinal cavity  20  that extends from the proximal and distal ends  210 ,  215  of the stent body  205 . Stent  200  may also further include proximal and distal rows of needles  35  and  40 . Stent body  205  may also include an optional reference marking  45 , as previously described. However, in contrast to other stent designs, stent  200  comprises a cylindrical, or substantially cylindrical, structure. Stent  200  and may be constructed using any of the previously described stent construction materials, such as superelastic and shape memory metals, alloys, plastics, and the like.  
     [0058]FIG. 7 is a cross-sectional view of stent  200  taken along line  7 - 7  of FIG. 6, showing the spatial relationship of the proximal row of needles  35  relative to the stent body  205 , and one another. Again, it is to be understood that the distal row of needles  40  may be configured using the same or different design used for the proximal row of needles  35 . Stent  200  may also include any of the needle configurations that can be utilized in the other stent designs, as previously described.  
     [0059] Alternative Delivery Catheter  
     [0060]FIG. 8 is a cross-sectional diagram of an alternative delivery catheter that may be used to deliver the stent of the present invention to a desired anastomosis site. Delivery catheter  220  is similar in many respects to the catheter shown in FIG. 3.  
     [0061] However, a notable distinction between these catheters is that the push rod  75  is shown configured with balloon inflation devices  225 ,  230  which may be used to respectively inflate/deflate balloons  235 ,  240  using, for example, an appropriate liquid or gaseous medium. One purpose of the balloons  235  and  240  is to facilitate the deployment and recovery of stent  200 .  
     [0062] Alternative Stent Deployment  
     [0063] FIGS.  9 A-C are cross-sectional diagrams showing relevant deployment operations that may be used to deploy the stent of the present invention, providing anastomosis of a urethra and bladder.  
     [0064]FIG. 9A shows that stent  200  may be positioned in its non-deployed state within the delivery catheter  220  and carried to the desired anastomosis region by advancing these devices through the urethra  85  until the distal end  65  of the catheter  220  is introduced into the bladder  90 . Optimally, positioning of the catheter  55  within the bladder  90  is such that the distal row of needles  40  are contained with the bladder  90 , while the proximal row of needles  35  are outside of the bladder  90 . Once again, reference markings  45  may be used for guidance in positioning the stent.  
     [0065] Once stent  200  has been properly placed within the bladder  90 , the delivery catheter  220  may be partially retracted, causing the release of at least a portion of stent  200  while a remaining portion of stent  200  remains contained within the catheter  220 . The partial release of stent  200  typically results in the deployment of the distal row of needles  40 . If necessary, the surgeon may manipulate (translate, rotate, etc.) the stent  200  within the bladder  90  to facilitate the proper engagement of the distal row of needles  40  within the bladder  90 .  
     [0066] Once acceptable placement of stent  200  within the bladder  90  has been achieved, the urethra  85  and bladder  90  may be brought into approximation (FIG. 9C. Next, the delivery catheter  220  may again be retracted so that the remaining (un-deployed) portion of stent  200  can be released, deploying the proximal row of needles  35  which are forced into communication with the urethra  85  by the expanding stent.  
     [0067] Inflatable balloons  235  and  240  may then be deflated using the balloon inflation devices  225 ,  230 . Once deflated, the rod  75  may then be retracted free from the fully deployed stent  200  and completely retracted along with the delivery catheter  220 . Removal of stent  200  may be accomplished in a manner similar to that utilized for the other stent embodiments, using, for example, the stent delivery catheter  220 .  
     [0068] While there have been shown what are presently considered to be preferred embodiments of the present invention, it will be apparent to those skilled in the art that various changes and modifications can be made herein without departing from the scope and spirit of the invention.