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BMG Endourethroplasty

BMG endourethroplasty is transurethral placement of buccal mucosa into a urethral stricture without an external urethral incision. Posterior grafting is supported mainly by small observational series and technical reports.

Transverse mucosal realignment (TUITMR) is a separate, nongraft technique.

Posterior grafting​

Chiou reported posterior endourethroplasty in 1988. His three-patient report described a two-step procedure: transurethral resection of scar to create a smooth grafting bed, then a full-thickness preputial graft held against the bed by an intraluminal balloon catheter. Two patients were stricture-free at more than 22 months and one at more than 12 months.[1]

Doležel's retrospective series included 38 patients treated during 1999–2022: 27 perineal repairs and 11 endourethroplasties. Perineal repair used ventral onlay or tubular buccal grafts; endourethroplasty used a catheter-mounted tubular graft after a cold-knife incision, with dilation first for tight stenosis.[2] For VUAS, the endoscopic incision extended deeply at 6 o'clock through adjacent bladder and urethral musculature into prerectal tissue; EAU 2026 strongly recommends against deep 6 o'clock DVIU for VUAS because of rectal-injury risk.[2][3] Three-year recurrence-free survival was 65% overall, with estimates of 63% for the perineal approach and 73% for endourethroplasty.[2] Selection and small groups preclude a conclusion of equivalence or superiority.[2]

The protocol allowed a cold-knife auxiliary DVIU for a short recurrence within 12 months. With auxiliary DVIU counted as part of treatment, the overall three-year result was 81%. One patient died of sepsis-associated multiorgan failure after auxiliary DVIU for a completely obliterative VUAS recurrence following perineal repair; prior salvage radiotherapy and possible retrovesical urine extravasation were noted.[2] New incontinence occurred in 2/18 patients continent before surgery; both cases followed perineal repair. No events were observed in the small endourethroplasty group.[2]

Selection limits

EAU advises against endoluminal treatment of a completely obliterated posterior stenosis. Assess radiation injury, fistula, tissue vascularity, bladder function and continence before selecting reconstruction.[3]

Endoscopic BMG with transurethral suturing​

Ungerer and Warner (2023) reported one radiated patient with an 8 mm flow-limiting membranous stenosis. Their technical sequence was:[4]

  1. Dilate the stricture enough for safe instrumentation. With a resectoscope, resect a superficial strip of mucosa about 1 cm wide from the bladder neck past the stricture to create the graft bed.
  2. Harvest buccal mucosa in standard fashion and leave the graft outside the urethra.
  3. Pass the RD180 suturing device transurethrally. Place a suture through the proximal end of the graft, then through the bladder neck, and back through the graft. Pulling the suture advances the graft into position on the bladder neck (the "pulley phenomenon").
  4. Anchor the graft to the posterior urethra with secure straps and leave a catheter to hold the graft flat. Catheter duration in this report was 4 weeks.

The procedure took 2.5 hours, with 50 mL estimated blood loss and same-day discharge.[4] Cystoscopy at 10 weeks showed good graft viability. Qmax improved from 4 to 20 mL/s, with no recurrence at 6 months.[4] A subsequent single-surgeon retrospective series of 28 men with membranous strictures (24 previously radiated, five obliterative) reported 23/28 with 17 Fr cystoscope passage at four months (median follow-up eight months); 16/28 later received an artificial urinary sphincter.[16] Three of 28 patients underwent cystectomy for radiation-related disease, including one delayed urosymphyseal fistula.[16] The superficial endoscopic bed differs from the pubic periosteal bed used in some open repairs, and resection must protect the sphincter and adjacent structures.[4] If DVIU is performed for VUAS or radiation-induced bulbomembranous stenosis, EAU 2026 strongly recommends avoiding deep incisions at 6 and 12 o'clock because of rectal injury and urosymphyseal fistula risk, respectively.[3]

Distal urethral inlay grafts​

Transurethral ventral and dorsal inlay BMG techniques for distal or fossa-navicularis strictures preserve the glans while replacing diseased lining.[5][6][7]

Ventral inlay (Sterling, Nikolavsky). The described steps are:[5]

  1. Excise the cicatrix by transurethral ventral urethrotomy until the lumen is at least 24 Fr.
  2. Deliver a triangular buccal graft to the proximal extent of the urethrotomy with a double-arm 6-0 polydioxanone suture and secure it externally.
  3. Secure the graft to the meatus with 5-0 polyglactin. Quilt it for spread fixation with additional 6-0 polydioxanone.
  4. Place a 16 Fr silicone catheter. Patients were discharged the same day and returned for a void trial at 1 week.

Dorsal inlay (Farrell, Vanni). The graft is placed dorsally through a transurethral approach. It is glans-sparing and avoids splitting the glans.[7]

SeriesDesignOutcome
Sterling 2023Single institution; 44 patients with at least 1 year of follow-up95% patent without further intervention at mean 36 months; both recurrences had stenosis extending more proximally and were treated with dorsal onlay BMG[5]
Daneshvar 202012 institutions; 68 enrolled, 57 with at least 12 months of follow-up54/57 (95%) stricture-free at median 17 months.[6]
Farrell 2022Single center; 16 patients, dorsal inlayAnatomic success 15/16 (93.8%) and functional success 16/16 (100%) at median 28.8 months; urinary tract infection 4/16 (25%); 83.3% of satisfaction respondents very satisfied[7]

These are retrospective series. The Sterling and Daneshvar cohorts may overlap.

Minced or liquid buccal grafts​

Liquid grafting suspends mechanically minced buccal micrografts in fibrin glue and injects them into the urethrotomy after DVIU. The concept has been tested in rabbits.[8][9]

  • Phase 1 and 2 (Nikolavsky 2016). Engraftment occurred in 2/3 rabbits in phase 1. In phase 2, all 6 treated animals showed engraftment with resolution or improvement of the stricture on urethrography and urethroscopy. Controls treated with fibrin glue alone showed fibrosis and chronic inflammation without engraftment.[8]
  • Randomized validation (Scott 2020). In 26 rabbits randomized to DVIU with liquid graft or DVIU with fibrin glue alone, engraftment occurred in 8/12 evaluable graft-treated rabbits (67%) vs 0/13 controls (p = 0.0005). Radiographic improvement was 58% vs 38% (p = 0.145), and median change in urethral diameter was 59% vs 41.6% (p = 0.29). Engraftment was more frequent, but neither radiographic improvement nor change in urethral diameter differed significantly; no functional voiding outcome was measured.[9]

Human bulbar-stricture data include Gaur's 30-patient uncontrolled pilot in short primary strictures and a later single-center comparison in primary strictures <4 cm: six-month success was 54/60 (90%) with minced grafting versus 22/30 (73.3%) with cultured buccal cells.[10][17] The studies share authors.[10][17] The authors reported 93.3% success at 12 months and 76.6% at 30 months, with seven recurrences; only 16/30 completed the 30-month visit, and the patient-level table assigns 30-month recurrences to patients with shorter recorded follow-up.[10] The 30-month estimate is therefore uncertain.[10][11] The liquid minced buccal graft page covers the preclinical and clinical evidence.

Positioning and VTE Prophylaxis​

These are endoscopic techniques performed in lithotomy, with buccal mucosa harvest requiring simultaneous oral access when a graft is used. The AUA guideline recommends assessing lower-extremity mobility beforehand and careful extremity padding in lithotomy to avoid pressure on the calf muscles, peroneal nerve and ulnar nerve, with sequential compression devices to reduce venous thromboembolism and nerve-compression injury; it frames added parenteral VTE prophylaxis mainly as a consideration for open urethral reconstruction rather than an endoscopic graft procedure such as this one. Neither the AUA nor EAU stricture guideline states a BNC- or VUAS-specific pharmacologic VTE recommendation; apply the general risk framework (age, obesity, prior VTE, malignancy, prolonged operation or immobility) on the VTE Prophylaxis page.[15]

Position in care​

Mucosal grafting requires viable tissue contact and secure fixation.

A 2024 meta-analysis of 40 endoscopic VUAS studies (1,452 patients) defined success as no VUAS recurrence at the end of each study's follow-up; the pooled median reported follow-up was 23.7 months (IQR 13–32).[12] Pooled success was 72.8% (95% CI 64.4–79.9%), or 62.9% (95% CI 53.6–71.4%) after trim-and-fill correction for publication bias.[12] Radiotherapy was associated with lower success.[12] A 2025 narrative review describes traditional endoscopic treatment (DVIU or dilation, with or without injectables) as successful in 40–72% of patients, with about 90% needing repeat intervention within 2 years. It reports short-term success approaching 85–90% for newer endoscopic techniques such as drug-coated balloon dilation and TUITMR.[13]

The AUA Urethral Stricture Disease guideline, amended in 2023, states that surgeons may perform dilation, vesicourethral incision or transurethral resection for post-prostatectomy VUAS .[14] It states that surgeons may perform robotic or open reconstruction for recalcitrant bladder neck or VUAS stenosis .[14] It does not address endourethroplasty.[14] Posterior endourethroplasty remains a specialist option that needs comparative and long-term evidence.[3]

Videos​

Endo-Laparoscopic Buccal Graft Repair of Post-Prostatectomy Bladder Neck Stenosis
Smets H, et al. Urology Video Journal 2023 (CC BY-NC-ND 4.0)
Open source videoRead the article

References​

1. Chiou RK. "Endourethroplasty in the Management of Complicated Posterior Urethral Strictures." The Journal of Urology. 1988;140(3):607-10. doi:10.1016/s0022-5347(17)41735-6

2. Doležel J, Hrabec R, Uher M, et al. "Substitution Urethroplasty With Buccal Mucosal Graft in the Management of Stricture of Vesicourethral Anastomosis or Membranous Urethra: Single-Institution Long-Term Experience With Perineal Approach and Endourethroplasty." Urology. 2024;192:126-132. doi:10.1016/j.urology.2024.05.034

3. European Association of Urology. EAU Guidelines on Urethral Strictures. 2026. Disease management in males, sections 6.3.5–6.3.6. Guideline.

4. Ungerer G, Kemble J, Sischka M, Balzano FL, Warner JN. "Endoscopic Urethroplasty Using Buccal Graft for Male Membranous Urethral Stricture." Urology. 2023;181:e200-e203. doi:10.1016/j.urology.2023.05.059

5. Sterling J, Daneshvar M, Nikolavsky D. "Transurethral Ventral Inlay Buccal Mucosa Graft Urethroplasty: Technique and Intermediate Outcomes." BJU International. 2023;132(1):109-111. doi:10.1111/bju.16007

6. Daneshvar M, Simhan J, Blakely S, et al. "Transurethral Ventral Buccal Mucosa Graft Inlay for Treatment of Distal Urethral Strictures: International Multi-Institutional Experience." World Journal of Urology. 2020;38(10):2601-2607. doi:10.1007/s00345-019-03061-6

7. Farrell MR, Campbell JG, Zhang L, Nowicki S, Vanni AJ. "Transurethral Reconstruction of Fossa Navicularis Strictures With Dorsal Inlay Buccal Mucosa Graft Urethroplasty." World Journal of Urology. 2022;40(6):1523-1528. doi:10.1007/s00345-022-03994-5

8. Nikolavsky D, Manwaring J, Bratslavsky G, et al. "Novel Concept and Method of Endoscopic Urethral Stricture Treatment Using Liquid Buccal Mucosal Graft." The Journal of Urology. 2016;196(6):1788-1795. doi:10.1016/j.juro.2016.05.028

9. Scott KA, Li G, Manwaring J, et al. "Liquid Buccal Mucosa Graft Endoscopic Urethroplasty: A Validation Animal Study." World Journal of Urology. 2020;38(9):2139-2145. doi:10.1007/s00345-019-02840-5

10. Gaur AS, Tarigopula V, Mandal S, et al. Modification of minced buccal mucosal graft endourethral urethroplasty: a pilot study. Indian J Urol. 2025;41:131–136. doi:10.4103/iju.iju_519_24.

11. Erratum: Modification of minced buccal mucosal graft endourethral urethroplasty: a pilot study. Indian J Urol. 2025. doi:10.4103/iju.iju_292_25.

12. Delchet O, et al. Post-prostatectomy anastomotic stenosis: systematic review and meta-analysis of endoscopic treatment. BJU Int. 2024;133(3):237-245. doi:10.1111/bju.16141.

13. Hudson CN, Damm T, Monn MF. "Minimally Invasive Treatments for Posterior Urethral Stenosis." Journal of Endourology. 2025;39(10):1078-1084. doi:10.1177/08927790251371037

14. Wessells H, Morey A, Souter L, Rahimi L, Vanni A. "Urethral Stricture Disease Guideline Amendment (2023)." The Journal of Urology. 2023;210(1):64-71. doi:10.1097/JU.0000000000003482

15. American Urological Association. Urethral Stricture Disease: AUA Guideline (published 2016; amended 2023), unabridged version. Guideline.

16. Ungerer GN, Pence ST, Findlay BL, et al. "Endoscopic buccal urethroplasty for membranous stricture disease." Transl Androl Urol. 2025;14(8):2383-2390. doi:10.21037/tau-24-430

17. Singh K, Gaur AS, Mandal S, et al. "Comparative efficacy of autologous adult live cultured buccal epithelial cells (AALBEC) and minced buccal mucosal graft endourethral urethroplasty (MBGEU) in male urethral stricture." Int Urol Nephrol. 2025;57(11):3567-3575. doi:10.1007/s11255-025-04526-x