Augmented Anastamotic Urethroplasty with Buccal Mucosal Graft Ventral Onlay
Lawrence L. Yeung M.D. and Steven B. Brandes M.D.
St. Louis, MO
An accurate evaluation of the number, length, location, and lumen diameter of the stricture is of paramount importance in determining the surgical approach to a urethral stricture. A retrograde urethrogram (RUG) is most useful in evaluating the anterior urethra from the external meatus to the proximal bulbar urethra. A voiding cystourethrogram (VCUG) should also be performed in conjunction with the RUG to achieve an accurate depiction of the proximal and functional extent of the stricture. The VCUG allows for evaluation of the proximal urethra by obtaining images of the open bladder neck and distended posterior urethra.
Retrograde urethrogram demonstrating a 4 cm mid to proximal bulbar urethral stricture with 1 cm region of more severe stenosis
Voiding cystourethrogram demonstrating opened bladder neck and membranous urethra and proximal extent of stricture with noted narrowing. This patient’s AUA symptom score was 30 with a maximum uroflow rate of 6 mL/second.
Timing of surgery
A stricture should be stable and no longer contracting before a urethroplasty is performed to minimize chances of surgery failure. Therefore, we prefer that the urethra not be instrumented for at least three months before any planned surgery, however, six weeks is usually acceptable. If the patient is in urinary retention or requires frequent intermittent self-catheterization, then we typically perform proximal urinary diversion with placement of a percutaneous suprapubic catheter to allow for resolution of any acute urethral inflammation and allow all strictured areas to declare themselves.
The location of the stricture can help to determine the surgical approach for repair, however, one must also have a plan B, C, D, etc. in their armamentarium when treating a urethral stricture. In general, we prefer to place our grafts dorsally when repairing the mid to distal bulbar and penile urethra because of the lack of a robust amount of corpus spongiosum available to provide an adequate vascular bed (spongioplasty) for the graft in these locations. However, in the proximal bulbar urethra, we prefer to place our grafts ventrally where the spongiosum is thick and performing the anastamosis is technically easier than placing the graft dorsally and there is adequate corpus spongiosum to perform a spongioplasty.
An augmented anastamotic urethroplasty combines the principles of both excision and substitution urethroplasty. It is especially useful when there is a long stricture with a focal area of dense scar and spongiofibrosis that can be excised and the remaining strictured urethra spatulated (either dorsally or ventrally depending on the location of the stricture) and the anastamosis augmented with a graft or flap. We will demonstrate an augmented anastamotic urethroplasty using a ventral onlay of buccal mucosal graft for the 4 cm stricture with 1 cm area of denser stricture seen in the RUG/VCUG above.
1. Position patient in dorsal (“social”) lithotomy using yellow fin stirrups with appropriate padding of all pressure points.
2. Place a 2-0 Prolene glans suture to place penis on stretch.
3. Place a 22 F red rubber catheter into the urethra up to the level of the stricture to help identify the urethra, taking care not to force the catheter through the stricture.
4. Use two penetrating towel clamps or 2-0 Prolene suture to tack the scrotum up to the suprapubic skin region temporarily until the Lonestar retractor is set up.
5. Make a midline perineal incision from the base of the scrotum to approximately 2 cm above the anus.
6. Use electrocautery to dissect through the subcutaneous fat and Colle’s fascia to expose the bulbospongiosus muscle.
7. Set up the Lonestar retractor to facilitate with exposure and secure the bottom of the retractor to the buttock skin using the penetrating towel clamps that are released from the scrotum from step 4.
8. Open the bulbospongiosus muscle sharply in the midline where the muscle fibers decussate in an avascular plane, and dissect it off the urethra using a combination of blunt dissection with the surgeon’s finger and a Kittner sponge. Retract the muscle onto the Lonestar using the hooks. Case must taken during dissection of the bulbospongiosus muscle so that it does not become macerated in order to preserve ejaculatory function.
9. Distract the urethra to one side using DeBakey forceps (treat it as you would a vascular structure) and then sharply dissect it free from the underlying corporal body by cutting down onto it using Metzenbaum scissors to roll the urethra over to one side, and then complete the circumferential dissection by repeating this maneuver on the other side. Care must be taken to not injure the corpus spongiosum or bleeding will occur. Small, perforating vessels from the corpus spongiosum to the corpus cavernosum can be easily controlled with bipolar cautery.
a. If a ventral onlay is to only be performed without plans for an augmented anastamosis (for strictures with an adequate urethral plate), then the urethra does not need to be mobilized circumferentially. The stricture can be exposed through a ventral urethrotomy and the graft sewn into place in this location. This is a quicker and easier operation to perform.
10. Encircle the urethra with a ¼ inch penrose drain to facilitate with retraction.
11. Dissect the urethra proximally by mobilizing the entire bulb and dividing the central tendon and separating it from the perineal body, as well as distally to the suspensory ligament of penis to provide adequate mobilization.
12. Flexible cystoscopy via the suprapubic tract can be performed to facilitate identification of the proximal extent of the stricture by turning the overhead lights down and marking the location of the cystoscope light on the urethra.
13. Inject methylene blue per urethra with 60 mL syringe to stain the urethral mucosa, which can help with identification of the mucosa after the urethra is opened. The scarred urethra and corpus spongiosum are white, so staining the mucosa facilitates suturing.
14. Transect the urethra across the region where the stricture is densest with the most spongiofibrosis present.
15. Place bulldog clamps on proximal and distal ends of transected urethra to obtain hemostasis.
16. Cut back on the stricture until a lumen is identifiable to allow for spatulation.
17. Spatulate urethra on ventral aspect of the proximal and distal ends of the urethra through the scarred mucosa until healthy appearing mucosa is reached. Place 4-0 Vicryl stay sutures at the apex and 3 and 9 o’clock positions on the urethral mucosa to facilitate with exposure of the lumen.
18. Calibrate the urethra proximally and distally to 28-30F with a bougie à boule to ensure all strictured urethra is opened.
19. Reapproximate the ends of the urethra while keeping the penis on stretch to prevent chordee or penile shortening and measure the resultant urethral defect to determine the size of graft that needs to be harvested. The paper packaging from sterile gloves can be cut out into the shape of the urethral defect and used as a template in the mouth to guide with the graft harvest.
20. Harvest the buccal mucosa graft.
Buccal mucosa graft (BMG) harvest technique
21. Have the anesthesiologist tape the endotracheal tube to the contralateral side from the graft harvest. Nasotracheal intubation is not necessary.
22. Wash the face and inner mouth with 1% hydrogen peroxide soaked sponges.
23. Pack the tongue medially with a 4 X 4 gauze
24. Mark the opening of Stensen’s duct for identification purposes, which is located next to the second molar.
25. Place 2-0 Prolene stay sutures 2 cm lateral and 1 cm posterior from the vermillion border of the mouth.
26. Place a Steinhauser buccal mucosal stretcher on the cheek and a mouth prop in the midline to hold the mouth open.
27. Mark out a graft 2 cm wide by 5-6 cm long (or use a template made with sterile paper glove packaging) with tapered ends to facilitate closure of the defect. Each cheek typically can yield a 6 cm long graft. Be sure to keep the cephalad margin away from Stensen’s duct and the anterior margin at least 1 cm away from the vermillion border to prevent retraction and esthetic problems of the mouth.
28. Inject 10-20 mL of 1% xylocaine with epinephrine 1:100,000 solution with a 22-gauge spinal needle to create a submucosal wheal under the entire graft and wait a few minutes before dissection to maximize hemostasis. Any bleeding can be controlled with bipolar cautery. Monopolar cautery should be avoided as the facial nerves are in proximity to this location.
29. Place three 3-0 chromic stay sutures at the apex and the two corners of the graft. Use the edge of a knife handle to push down on the middle of the graft to provide counter-traction and use a number 15 blade to score the graft edges down to the fat. Use Metzenbaum scissors to dissect the graft superficial to the buccinator muscle. An index finger and a gauze soaked in epinephrine solution provides counter-traction against the buccinator muscle.
30. After the graft is harvested, pack an epinephrine soaked gauze into the mouth to facilitate with hemostasis.
31. De-fat the graft while it is stretched over the surgeon’s index finger by pressing the mid portion of Metzenbaum scissors down against the graft and cutting the fat off.
32. Pin the graft to a foam pad and scrape the remainder of the fat with the edge of a number 15 blade to emulsify it. The graft is ready when newsprint lettering is visible through the graft.
33. After the graft is de-fatted, close the harvest site with interrupted 3-0 chromic suture.
Augmented anastamosis with dorsal end-to-end anastamosis and ventral BMG onlay technique
34. Place a 4-0 Vicryl stay suture at each apex of the BMG and hang it from the Lonestar retractor.
35. Place the penis on full stretch to prevent penile shortening and then mark out where distal end of graft should lie on the corpora to allow for a tension free anastamosis of the two ends of the dorsal urethral plate.
36. Place five 4-0 Vicryl interrupted sutures (soaked in mineral oil to facilitate passage of suture through tissue) taking bites of proximal and distal urethral mucosa as well as a bite of the tunica of the corpora underneath to anchor the dorsal end-to-end anastamosis. Tag the two lateral sutures with a hemostat.
37. Place three to five proximal 4-0 Vicryl sutures through proximal spatulated apex of urethral mucosa and then pass the suture through the BMG (epithelium side facing lumen of urethra) in the corresponding site and tie down.
38. Suture the right lateral edge of BMG to urethral mucosa, while taking a small bite of the tunica of the corpora laterally, with a running 4-0 Vicryl up toward distal end of urethral opening. Repeat this for the left side of the graft.
39. Place final 16F silicone catheter into bladder through the penis and inflate the balloon.
40. Complete anastamosis with interrupted 4-0 Vicryl through the distal apex.
41. Perform spongioplasty by undermining the tunica of the spongiosum off the urethra with a #15 blade to facilitate its closure. Run the spongiosum closed vertically with 4-0 Vicryl and then close the transverse defect with running 4-0 Vicryl suture as well.
42. Close bulbospongiosus muscle with running 2-0 Vicryl.
43. Close deep fat and then Colles with running 3-0 Vicryl.
44. Close skin with 4-0 Vicryl running horizontal mattress suture.
An ice pack can be placed to the cheek for 24 hours to decrease pain and swelling from the BMG harvevst. We prescribe Peridex swish-and-spit four times a day as prophylaxis against infection of the buccal mucosa harvest site for about one week. The Foley is left in place for 3 weeks and then a peri-catheter retrograde urethrogram is performed to rule out contrast extravasation before the catheter is removed.
|Lawrence Yeung, M.D.
Urologic Reconstructive Fellow
|Steven B. Brandes, M.D.
Director, Section of Reconstructive Urology
Urology Residency Director