用預製的縫匠肌-頰黏膜復合皮瓣修復複雜的前列腺尿道缺損：一例罕見病例報告 ：困難案例報告

黃韋鈞、楊啟瑞、方仁愷

中國醫藥大學附設醫院 泌尿部

Complicated prostate urethra defect repaired with prefabricated gracilis-buccal mucosa composite flap: a rare case report.

Wei-Chun Huang, Chi-Rei Yang, Jen-Kai Fang

Department of Urology, China Medical University Hospital, Taichung, Taiwan

Introduction:

Urethral stricture is characterized by the narrowing of the urethra, often resulting from scarring or fibrosis due to injury, infection, surgery, or inflammation. Most urethral strictures occur in the anterior urethra, while stenoses in the posterior urethra remain relatively underexplored. The management of posterior urethral stenosis depends on the underlying etiology and the patient's anatomy, with treatment options ranging from catheter indwelling to more invasive procedures such as abdominoperineal reconstruction. Here, we present a case of a devastating prostate urethral defect, which was successfully repaired using a gracilis-buccal mucosa composite flap.

Case:

This 65-year-old man has a past history of rectal cancer with lung metastasis and is status post-video-assisted thoracoscopic surgery (VATS) right lower lung wedge resection on 2016/11/03. He also underwent Hartmann's operation for removal of the distal rectum and previous anastomosis (ischemic changes) on 2023/08/10. During the operation on 2023/08/10, it was complicated by a 1 cm posterior wall urethral injury at the apex of the prostate, which was repaired primarily with 3-0 Monocryl and Vicryl sutures via the anal wound. A Foley catheter was indwelled at that time and he was regularly replace new Foley from cystoscopy during follow-up visits to the GU OPD.

After 11 times Foley catheter replacements, a defect in the prostate urethra was still noted, and it had not healed. A second time primary repair was performed on 2023/11/06, in collaboration with the colorectal surgeon. During the operation, cystourethroscopy was performed to inspect the defect at the bladder neck and prostatic urethra. A poor healing of the 3 cm prostatic urethral defect was observed, but it was difficult to approach the defect from the perineum wound. The prostate was repaired via the perineum with 3-0 Vicryl sutures as much as possible. However, the posterior prostate urethral defect persisted, and a pocket was still present. A cystogram revealed contrast leakage from the posterior prostate urethra. We then discussed with a plastic surgeon for flap reconstruction. Considering the previous surgical history and surrounding scar tissue with urine culture positive for pseudomonas, a two-stage gracilis-buccal mucosa composite flap reconstruction was proposed.

In stage 1, two mucosal grafts, measuring 6 x 4 cm, were harvested. The grafts were sutured to the distal part of the gracilis muscle using 3-0 PDS sutures. After achieving hemostasis, a membrane was used to protect the mucosal grafts, which were wrapped around the gracilis muscle. Four weeks later, in stage 2, the gracilis-buccal mucosa composite flap was harvested. The entire gracilis muscle, including the distal portion carrying the mucosa graft, was dissected. The mucosal graft survived well, and the blood vessels of the flap were preserved. The flap was transposed through a subcutaneous space to reach the posterior urethra. The urethral defect was repaired using the pruned 3 x 2 cm buccal mucosa graft from the left gracilis flap, with interrupted 3-0 Vicryl sutures from the membranous urethral edge to the posterior bladder neck. A 20 Fr 2-way silicone Foley catheter with a 7 cc balloon was indwelled. The Foley catheter was tested with a Toomey syringe, and smooth irrigation was noted with no leakage from the sutured urethra.

Three months postoperatively, urethrogram showed contrast from the bulbar urethra to the bladder, with no extravasation. Cystoscopy revealed smooth penile urethra, bulbar urethra, and prostatic urethra, with sutures and scars healing well. The patient reported fair voiding without urine leakage or incontinence. He is now currently free from catheterization and had previously life quality.

Conclusion:

This case highlights the feasibility of repairing a large, non-healing prostate urethral defect using a prefabricated gracilis-buccal mucosa composite flap. The gracilis muscle provides a vascular bed, reducing the risk of graft failure and subsequent stenosis after reconstruction. This approach offers a promising option for complex urethral defects, particularly in the posterior urethra, where tissue regeneration may otherwise be challenging.