scrotum, covering the proximal perineum and urethral reconstruction with the pudendal flap and transferring the scrotal bridge laterally (O Fig. 19.5).
A small, round Jackson-Pratt suction drain that exits through the thigh incision is inserted for 4 days. The urethral catheter is removed in 10 days and the suprapubic diverting cystotomy in 3 weeks pending normal results on voiding cystourethrogram. A retrograde urethrogram is obtained every 3-6 months and repeat uroflows are checked every 4 months for 2 years.
Pelvic fractures or perineal injuries can produce long defects from the apex of the prostate to the mid bulbar urethra that cannot be bridged by standard anastomotic techniques because of a very lengthy defect, vascular compromise of the anterior urethra, or prior anterior urethral surgery and associated spongiofibrosis that interferes with retrograde blood flow. This will require the uncommon use of a circumferential one- or two-stage tube flap design as a salvage procedure to restore the proximal urethral lumen. The perineum is exposed with the patient in the lithotomy position and the sacrum elevated by wedge or gel-pack pillow. The bulbomembranous and prostatic apex is explored through an inverted Y-incision, dividing the central tendon and bulbocavernosus muscle in the midline.
The crura of the corpora cavernosa are separated in the midline by dividing the intercrural membrane to achieve access to the prostatic lumen. The membranous and prostatic apical urethra are spatulated ventrally along with the distal bulbous urethral stump. The segment of obliterated urethra and periurethral fibrous tissue between the two openings is excised.
The perineal artery flap is raised and its length extended to the maximum point of viability. A central distal island of skin is measured to fit the size of the defect and marked with a skin scribe to a width of 3-3.5 cm and
a length of 6-8 cm. The skin margin surrounding the demarcated island flap is de-epithelialized, leaving a telltale bleeding dermis while preserving the circulation to the potential island tube flap (O Fig. 19.6). The proximal margin is de-epithelialized for a minimum of 3 cm.
The skin strip island (1) is tabularized around a #22 F catheter (2), and the edge is closely initially with a few well-spaced interrupted sutures of 4-0 Monocryl (3) followed by running subcuticular sutures of 5-0 Monocryl (4) (O Fig. 19.7).
The distal stoma of the tube flap is coapted to the proximal prostatic apex with closely placed 4-0 Monocryl tied on the outside of the lumen. The proximal tube stoma is brought to the bulbous urethral lumen after mobilizing the corpora spongiosa to the penoscrotal junction and completing the distal anastomosis with interrupted 4-0 Monocryl (O Fig. 19.8).
The wounds are closed in layers by advancing the thigh margins of the incision medially and the proximal portions of the flap as a posterior cover (O Fig. 5).
A recurrent bulbomembranous stricture that has undergone prior failed procedures, or radiation with extensive periurethral fibrosa and loss of adequate scrotal or peri-neal skin cover can be salvaged by transferring the Singapore flap to the proximal spatulated urethrostomy. This technique can be accomplished by bringing the tapered distal flap margin to the apex of the ventral urethrotomy, thus delaying the definitive urethral reconstruction by an initial marsupialization procedure (O Fig. 19.9). The flap is elevated after the urethra is prepared and rotated to the urethral margin. The proximal part of the flap is concomi-tantly used as a wound cover while the nonhirsute scrotal edge is sutured to the distal urethral edge (O Fig. 19.10). A 20-F silastic catheter is placed thru the proximal stoma for bladder drainage for 12 days and evaluation continues periodically by bougie calibration (O Fig. 19.11).
□ Fig. 19.6. The island of skin is measured and demarcated in preparation for a tubed flap to bridge a long defect that cannot be repaired by standard anastomotic techniques
□ Fig. 19.10. The flap used as perineal wound cover
□ Fig. 19.10. The flap used as perineal wound cover
□ Fig. 19.11. Completed first stage is monitored periodically by bougie calibration. The second stage is performed only when the two stomas are proved stable
Chapter 19 • Selective use of the Perineal Artery Fasciocutaneous Flap (Singapore) in Urethral Reconstruction Clinical Experience References
From 1992 to the present, 13 patients ranging in age from 29 to 72 years have undergone urethral reconstruction using a perineal artery fasciocutaneous flap. The length of the stricture varied from 3 to 12 cm and follow-up ranges from 1 to 10 years. These strictures were located uniformly in the proximal bulbomembranous and prostato-membranous urethra. Seven patients underwent an onlay island patch flap. Five of these were referred after several prior failed repairs, and two patients had been treated with radiation therapy for carcinoma of the prostate. Two of these patients required combined addition of a buccal graft onlay. Four patients underwent one-stage tube flap proximal urethral interposition for post-traumatic 6- to 8-cm urethral gaps. One of these was restrictured and underwent a multistage marsupialization procedure without a second stage. Two patients have been managed by a first-stage procedure, one for a radiation stricture and a distal urethrectomy, and one for an extensive stricture with transmembranous component that worsened with massive perineal fibrosis after 12 prior failed attempts at reconstruction.
There were no fistulas, diverticula, or problems with wound healing. Two patients experienced a transient anterior compartment syndrome, and two patients required drainage and antibiotics for a donor-site wound infection. A hematoma developed in one flap under its medial border, but no loss of skin or the onlay island was encountered.
The Singapore or perineal artery flap is a medial thigh sensate, axial-patterned fasciocutaneous flap based on the terminal branches of the internal pudendal artery. It is a reliable extragenital skin flap that has the potential of salvaging a subset of complex proximal bulbomemb-ranous and prostatomembranous strictures and urethral segmental loss that are not suitable for grafts or genital flaps. It is a thin, pliable flap that is simple in design and easy to harvest with consistent, well-defined borders. It is frequently nonhirsute with a robust, reliable pedicle, and it is transferred readily to the proximal urethra without tension. The donor site creates no significant morbidity of skin loss or deformity and lends itself to primary closure without the need for covering skin grafts. Patients with proximal urethral radiation strictures after therapy for prostate, urethral, and rectal carcinoma are candidates for repair with this easily elevated flap since the radiation does not preclude its use.
1 Zinman L (1997) Perineal artery axial fasciocutaneous flap in urethral reconstruction. Atlas of Urol Clinics North Am 5:91-107
2. Wee JTK, Joseph VT (1989) A new technique of vaginal reconstruction using a neurovascular pudendal thigh flap: a preliminary report. Plast Reconstr Surg 83:701-709
3. Ponten B (1981) The fasciocutaneous flap: its use in soft tissue defects of the lower leg. Brit J Plast Surg 34:215-220
4. Cormack GC, Lamberty BG (1984) A classification of fasciocutaneous flaps according to their patterns of vascularization. Brit J.Plast Surg 37:80-87
5. Goldwyn RM (1977) History of attempts to form a vagina. Plast Reconstr Surg 59:319-329
6. Morton KE, Davies D, Dewhurst J (1986) The use of the fasciocutaneous flap in vaginal reconstruction. Br J Obstet Gynecol 93:970-973
7. Hagerty RC, Vaughn TR, Lutz MIJ (1988) The perineal artery axial flap in reconstruction of the vagina. Plast Reconst Surg 82:344345
8. Giraldo R, Solano A, Mora MJ (1996) The Milaga flap for vaginoplasty in the Mayer-Rokitansk-Kuster-Hauser syndrome: experience and early term results. Plast Reconst Surg 98:305-312
9. Tzarnas CD, Raezer OM, Castillo OA (1994) A unique fasciocutaneous flap for posterior urethral repair. Urology 43:379-381
10. Monstrey S, Blondel P, Van Lanphy TK, Verpaele A, Tonnard P Mat-ton G (2001) The versatility of the pudendal thigh fasciocutaneous flap used as an island flap. Plast Reconst Surg 107:719-725
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