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Ventral BMG + Gracilis Muscle Flap (Vanni / Zinman)

Ventral buccal mucosal graft (BMG) urethroplasty with gracilis muscle flap is a specialized reconstructive technique reserved for high-risk, long-segment urethral strictures with a compromised graft bed and poor local vascular supply, where standard urethroplasty is unlikely to succeed.[1][2] The Lahey Hospital group (Zinman, Vanni and colleagues) reported this operation in two overlapping retrospective series covering 20 years (20 and 30 patients).

For the foundations gracilis-muscle-flap article (anatomy, harvest principles, multi-organ applications), see Gracilis Flap. For graft material principles, see Buccal Mucosa Graft. For other combined graft + flap urethroplasties, see Combined Dorsal BMG + Ventral Fasciocutaneous Flap (Erickson). For gracilis use in rectourethral fistula repair (Lahey), see the Rectourethral Fistula article.

Rationale​

A free graft (BMG) requires a well-vascularized recipient bed for imbibition and inosculation. In patients with radiation-damaged tissue, prior failed urethroplasty, or extensive periurethral fibrosis, the native corpus spongiosum cannot provide adequate blood supply. The gracilis muscle flap is harvested and transposed to serve as a new vascularized graft bed for the ventral BMG, replacing the deficient spongiosum.[1][2]

Beckenstein 1996 documented epithelial migration after gracilis coverage of a partial urethral defect in one patient with Fournier's gangrene.[4]

Indications​

Selection depends on the urethral defect and recipient-bed quality. In radiation-damaged posterior disease, assess bladder capacity, compliance and function, necrosis, calcification, fistulation and incapacitating local symptoms before reconstruction; the EAU recommends urinary diversion in recurrent or complex cases with loss of bladder capacity or incapacitating local symptoms .[12]

  • Radiation-induced strictures were the most common etiology, at 45–60% of cases.[1][2]
  • Prior failed urethroplasty was present in 33–45% of patients.[1][2]
  • Post-prostatectomy strictures accounted for 10–23.3% in the overlapping cohorts.[1][2]
  • Long-segment strictures had a mean length of 7.6–8.2 cm (range 3.5–15 cm) across the overlapping cohorts.[1][2] The stricture involved the posterior urethra, with or without the bulbar urethra, in 50–60% of patients.[1][2]
  • Strictures after transurethral surgery, trauma or failed hypospadias repair are also included.[1]
  • Prior UroLume stent placement was present in 10–15% of patients.[1][2]

Surgical Technique​

The procedure as described by Palmer, Zinman, and Vanni:[2]

StepDetail
1. PositioningLithotomy; perineal incision provides access to the urethra
2. Urethral mobilizationVentral urethrotomy through the full length of the stricture; the bulbocavernosus muscle is divided and preserved at this stage for later fixation to the transferred gracilis (Step 6). Debride or excise diseased / fibrotic spongiosum as needed; Zinman cautions against routine excision of extensively fibrotic or radiated spongiosum unless a segment is obliterated, since the expected elasticity may be absent and further excision may produce ventral penile tethering[11]
3. BMG harvestInner cheek(s); both cheeks for long strictures. Defat and prepare the graft[3]
4. Ventral BMG insetSuture the graft as a ventral onlay patch to healthy urethrotomy margins; place its external surface in contact with the vascularized muscle. This differs from quilting an inlay to the urethral plate
5. Gracilis harvestMobilize the gracilis while identifying and preserving its dominant proximal vascular pedicle; divide distal attachments and secondary pedicles as required for tension-free reach. See the linked flap-anatomy article[2][4]
6. Tunneling and insetTunnel the muscle subcutaneously to the perineum; wrap the gracilis over the ventral BMG as a vascularized graft bed, then suture the preserved bulbocavernosus muscle to the lateral surface of the transferred gracilis for fixation[11]
7. Closure and catheter removalSecure the muscle flap and close the perineum in layers over a urethral catheter. Before catheter removal, assess for extravasation with validated urethrography ; maintain drainage and repeat imaging if a significant leak persists[14]

Outcomes​

SeriesnMean strictureSuccessMean FUTime to recurrenceRadiation etiologyPrior urethroplastyAUS placement
Palmer 2015[2]208.2 cm (3.5–15)80%40 mo10 mo (2–17)45%45%25%
Rozanski / Vanni 2020[1]307.6 cm (3.5–15)76.7%32 mo (4–92)8 mo (2–17)60%33.3%23.3%

Success was defined by absence of recurrent narrowing preventing passage of a 16-Fr cystoscope in the 2015 report and a 17-Fr cystoscope in 2020. The later cohort expands the earlier experience.[1][2] For graft-and-flap repair, EAU 2026 recommends at least one year of follow-up , three-month flexible cystoscopy , and a risk-adjusted protocol ; its standard-risk proposal for graft/flap substitution includes uroflowmetry and patient-reported outcomes at three, 12 and 24 months and five years; anatomic assessment at three, 12 and 24 months, and at five years if indicated; and consideration of longer follow-up after substitution repair.[13]

Among failures, salvage options included urinary diversion (ileal loop), suprapubic tube placement, endoscopic dilation, or DVIU.[1][2]

Complications​

  • Postoperative incontinence requiring AUS was reported in 5/20 (25%) and 7/30 (23.3%) patients in these overlapping cohorts.[2][1]
  • Stricture recurrence occurred in 20–23%, at a mean of 8–10 months (range 2–17).[1][2]
  • Gracilis donor-site morbidity is generally low. Studies in non-urologic contexts report an approximately 11% decrease in hip-adduction strength that patients did not notice, hypoesthesia in the obturator-nerve distribution in approximately 40% (Deutinger, 42 patients), and thigh-contour deformity in 59% of myocutaneous flaps (Papadopoulos, 29 flaps).[5][6] In the Papadopoulos series, flap necrosis (13.8%) was associated with BMI > 25, smoking and recipient-site radiation.[6]

Where It Fits in Urethral Reconstruction​

This technique occupies a specific niche. The AUA 2023 urethral stricture guideline amendment recommends oral mucosa as the first-choice graft material .[7] The AUA Moderate Recommendation (Grade C) addresses long multisegment strictures, most commonly defined as >10 cm spanning both the penile and bulbar urethra, and permits one-stage or multistage reconstruction with oral mucosal grafts, penile fasciocutaneous flaps, or both.[7] In a 2024 GURS survey (134 of 350 invited surgeons responded), 66% preferred dorsal and 34% ventral placement for bulbar BMG urethroplasty.[3] When the local tissue is too compromised for standard graft take, the gracilis muscle flap can provide a vascularized recipient bed.[12] For radiation-induced bulbomembranous stricture, counsel about de novo incontinence and new erectile dysfunction after urethroplasty .[12]

Other vascularized-flap options in this setting include the rectus abdominis flap and omental flap (used in robotic posterior urethroplasty).[8] Gracilis is commonly used in the perineal approach because of its proximity, reliable pedicle, expendability and ease of harvest, with limited but possible functional donor morbidity.[9][10]

Videos​

Urethral Reconstruction With BMG, Gracilis and Tunica Vaginalis Flaps
Plastic Surgery Education
Gracilis Muscle Flap for Urologic Reconstruction
Jeremy Myers, TURNS

References​

1. Rozanski AT, Vanni AJ. Ventral buccal mucosa graft urethroplasty with gracilis muscle flap for high-risk, long-segment urethral strictures: a 20-year experience. Urology. 2020;140:178-180. doi:10.1016/j.urology.2020.03.008.

2. Palmer DA, Buckley JC, Zinman LN, Vanni AJ. Urethroplasty for high-risk, long-segment urethral strictures with ventral buccal mucosa graft and gracilis muscle flap. J Urol. 2015;193(3):902-905. doi:10.1016/j.juro.2014.09.093.

3. Berg C, Singh A, Hu P, et al. Current trends in the use of buccal grafts during urethroplasty among Society of Genitourinary Reconstructive Surgeons. Urology. 2024;191:139-143. doi:10.1016/j.urology.2024.06.019.

4. Beckenstein M, Smith AA, Dinchman K, Wyatt-Ashmead J, Meland NB. Muscle flap reconstruction aids in urethral regeneration. Ann Plast Surg. 1996;36(6):641-643. doi:10.1097/00000637-199606000-00014.

5. Deutinger M, Kuzbari R, Paternostro-Sluga T, et al. Donor-site morbidity of the gracilis flap. Plast Reconstr Surg. 1995;95(7):1240-1244. doi:10.1097/00006534-199506000-00015.

6. Papadopoulos O, Konofaos P, Georgiou P, et al. Gracilis myocutaneous flap: evaluation of potential risk factors and long-term donor-site morbidity. Microsurgery. 2011;31(6):448-453. doi:10.1002/micr.20899.

7. Wessells H, Morey A, Souter L, Rahimi L, Vanni A. Urethral stricture disease guideline amendment (2023). J Urol. 2023;210(1):64-71. doi:10.1097/JU.0000000000003482.

8. Liu W, Shakir N, Zhao LC. Single-port robotic posterior urethroplasty using buccal mucosa grafts: technique and outcomes. Urology. 2022;159:214-221. doi:10.1016/j.urology.2021.07.049.

9. Ryan JA, Gibbons RP, Correa RJ. Urologic use of gracilis muscle flap for nonhealing perineal wounds and fistulas. Urology. 1985;26(5):456-459. doi:10.1016/0090-4295(85)90153-0.

10. Zinman L. Extragenital muscular myocutaneous and fasciocutaneous flaps in urethral reconstruction. Urol Clin North Am. 1997;24(3):683-698. doi:10.1016/s0094-0143(05)70408-0.

11. Zinman LN. Combined use of fasciocutaneous, muscular and myocutaneous flaps and graft onlays in urethral reconstruction. In: Montague DK, Gill IS, Angermeier KW, Ross JH, eds. Textbook of Reconstructive Urologic Surgery. Informa Healthcare; 2008:489.

12. European Association of Urology. "EAU Guidelines on Urethral Strictures: Disease Management in Males." 2026. Guideline

13. European Association of Urology. "EAU Guidelines on Urethral Strictures: Follow Up." 2026. Guideline

14. European Association of Urology. "EAU Guidelines on Urethral Strictures: Perioperative Care of Urethral Surgery." 2026. Guideline