邱士庭¹，楊弘維²，官振翔²，李苑如¹

國立台灣大學附設醫院 泌尿部¹; 國立台灣大學附設醫院 整形外科²

Shih-Ting Chiu¹, Hung-Wei Yang², Chen-Hsiang Kuan², Yuan-Ju Lee¹

Department of Urology, National Taiwan University Hospital¹

Department of Plastic and Reconstructive Surgery, National Taiwan University Hospital²

 

      Necrotizing fasciitis of the scrotum and perineum, known as Fournier gangrene, is an acute and potentially lethal infectious event. Broad-spectrum antibiotics and timely surgical debridement are warranted. Extensive debridement of the necrotic tissue might result in loss of scrotal tissue and exposure of urethra and testis. Common available options for scrotal reconstruction include split thickness skin grafts, scrotal advancement flaps, local fasciocutaneous, muscle or myocutaneous flaps, and free flap transfer. As for urethral reconstruction, substitute urethroplasty using buccal mucosa has become the preferred choice if anastomotic urethroplasty was not feasible for the long urethral defect; however, a well-vascularized graft bed is essential for buccal mucosa graft to attach and thrive.

      We report a case of a 63-year-old Taiwanese diabetic man who initially had scrotal erythema and swelling for one week and did not seek medical help until progressive scrotal swelling with pain and fever occured. He had antibiotic treatment in local hospital and was transferred to our hospital due to pending shock status. Physical examination revealed erythematous scrotum with odorous pus formation. Contrasted computed tomography showed soft tissue swelling with air and fluid collection at penis, scrotum, and perineum without extension to abdomen. Pus culture yielded Bacteroides spp. Fournier gangrene was impressed. Wound debridement, colostomy, cystostomy and Foley placement were performed. Extensive non-viable necrotic tissue over scrotum, proximal ventral penis and more than half of ventral penile urethra was removed, while bilateral testes were spared. The testes and 8cm penile urethra were exposed after debridement.  He had systemic antibiotics and wound wet dressing for one month, followed by reconstruction surgery.

      First, the residual dorsal penile urethra was rolled up as a tube at the proximal and distal end of the urethral defect to shorten the long defect length, which was later repaired with 6cm buccal mucosa graft. Then, the gracilis muscle was harvested and rotated into the perineum. It was secured around the buccal mucosa graft and also filled the scrotal defect. Lastly, split-thickness skin graft lay over the granulation tissue and muscle flap. The skin graft site healed well without active infection. This patient would receive urethroscopy after one month of the reconstruction.

       Substitute urethroplasty with buccal mucosa allows long segment urethral reconstruction with success rate between 79 - 96%. However, insufficient blood supply and tissue support might increase the risk of failure, such as scarred tissue in previous radiotherapy or surgery.  In our case, we managed this with gracilis muscle flap, which provides extra tissue transfer and reliable vascularity for the graft. Besides, gracilis muscle flap is in approximation to scrotum and could cover the scrotal defects with deep pockets. Its good vascularization holds great resistance to micro-organisms infection.