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Labial Mucosa Graft (LaMG)

The labial mucosa graft (LaMG) is a free mucosal graft harvested from the inner surface of the lower lip (mandibular labial mucosa) — the third oral mucosal donor site alongside buccal (inner cheek) and lingual (tongue) mucosa for urethral and urogenital reconstruction. The AUA Urethral Stricture Disease Guideline (2023) recognizes the inner lower lip as a valid oral-mucosa harvest site for urethroplasty.[1] The largest single-surgeon series — 204 female patients undergoing dorsal-onlay LaMG urethroplasty for female urethral stricture — demonstrated 93.5% clinical success at 2 years with no significant donor-site morbidity, establishing LaMG as a particularly valuable graft for female urethral reconstruction.[2]

See the overview article for graft-selection principles: Grafts in GU Reconstruction, and the anatomy article: The Oral Cavity.

Nomenclature — labial = lip, not vulva

"Labial mucosa graft" in urology refers to the inner lower lip (mandibular labial mucosa) — not the labia majora or labia minora of the vulva. Some authors use "buccal mucosa" generically to mean any oral mucosal graft including lower-lip harvest. WARWIKI uses labial = lip, buccal = inner cheek, lingual = tongue, and the labia-majora fasciocutaneous flap is a separate vulvar-donor flap covered elsewhere.[3][4]

Anatomy of the Lower Lip Donor Site​

Mucosal surface. The inner lower lip is lined by non-keratinized stratified squamous epithelium with a thin, highly vascular lamina propria — histologically identical to buccal and lingual mucosa and similar to urethral epithelium. Minor salivary glands sit in the submucosa.[3][5]

The mental nerve — the critical neurovascular structure​

The mental nerve exits the mental foramen of the mandible (typically below the second premolar) and provides sensory innervation to the lower lip, chin, and labial mucosa. It is the most important anatomical consideration during labial-mucosa harvest and the substrate for the page's central trade-off (longer postoperative numbness vs cheek harvest).[3][6][7]

  • The mental nerve divides into 3 main branches — one descending to the chin skin and two ascending to supply the lower lip skin and mucosa.[7][8]
  • Toure 2023 identified three intralabial mental-nerve patterns: Type I (no contralateral connections), Type II (connections in the upper third of the lip), and Type III (connections throughout the lip). Types II and III allow sensory recovery after unilateral nerve injury.[8]
  • Won 2014 showed that mental-nerve branches overlap with adjacent branches in 50% of cases and anastomose with the buccal nerve in 60% — providing a degree of redundant innervation that mitigates, but does not eliminate, donor-site numbness risk.[7]

Graft dimensions​

The lower lip provides a smaller graft area than the inner cheek:

SiteLength (single)Length (bilateral)Width
Labial (lower lip)3.5–6 cmup to 7–8 cm (upper + lower lip)1.5–2.0 cm
Buccal (inner cheek)6–7 cm12–14 cm (both cheeks)1.5–2.5 cm
Lingual (tongue)9–12 cm16–20 cm (across tip)1.0–1.5 cm

Sources: Wessells 2023, Castagnetti 2009, Dessanti 1995.[1][9][10]

Histological Properties​

Labial mucosa shares the histology that makes all oral mucosa ideal for urethral reconstruction:[5][11]

  • Non-keratinized stratified squamous epithelium — similar to urethral epithelium
  • Thick epithelium resistant to mechanical stress
  • Thin, highly vascular lamina propria — early imbibition and inosculation
  • Resistant to infection in a wet environment
  • Compatible with the urinary milieu
  • "Scarless healing" phenotype — rapid re-epithelialization, minimal inflammation, tightly controlled fibroblast activity reflecting fetal-like wound-healing biology[11]

After engraftment to the urethra, oral mucosa retains its histopathological characteristics and is not overgrown by urothelium even after prolonged urine exposure — a finding that may explain the durable superiority of oral mucosa over other graft materials for urethral reconstruction.[12]

Harvest Technique​

The technique for lower-lip labial-mucosa harvest:[3][9][10]

  1. Anesthesia — general anesthesia (in conjunction with the urethral procedure) or local infiltration with lidocaine + epinephrine.
  2. Exposure — lower lip everted and retracted with stay sutures or a lip retractor.
  3. Graft marking — outline on the inner mucosal surface, staying well above the gingivolabial sulcus and lateral to the midline frenulum. Boundaries must avoid mental-nerve branches entering the lip from the mental foramen.
  4. Incision and harvest — submucosal-plane sharp dissection. Preserve the underlying orbicularis oris and the deeper mental-nerve trunks. The graft includes epithelium, lamina propria, and a thin layer of submucosa (with included minor salivary glands).
  5. Graft preparation — placed in saline; excess submucosa trimmed from the deep surface.
  6. Donor-site closure — primary closure with 4-0 polyglactin (Vicryl), or left open to heal by secondary intention.
  7. Postoperative care — oral fluids within 24 h; soft solids by day 2; normal diet by 1 week.[3]

Combined harvest. When longer grafts are needed, labial mucosa can be harvested from both upper and lower lips, or combined with buccal or lingual mucosa to maximize total graft length.[10][13]

Applications in Urology and Urogynecology​

1. Female urethral stricture — the dominant modern indication​

The strongest contemporary evidence for LaMG comes from female urethral stricture repair.

Jena 2025 — the largest single-surgeon series of dorsal-onlay LaMG urethroplasty for female urethral stricture:[2]

  • 204 patients, June 2013 – July 2024
  • Mean operative time 97.7 ± 13 min; median LOS 2 days
  • Perioperative complications 2.94% (Clavien-Dindo grade 2–3); no significant donor-site morbidity
  • Clinical success 98.5% at 1–3 mo, 97.5% at 6 mo, 93.5% at 2 yr
  • Recurrence 6.5% at 2 yr (4 required repeat urethroplasty)
  • Symptom improvement (GII) 95% at 1–3 mo, 88.1% at 2 yr
  • Median follow-up 29 months (7–131)

This series establishes dorsal-onlay LaMG urethroplasty as a safe, effective, and durable treatment for female urethral stricture, with the largest published experience to date for any oral-mucosa graft in this indication.

2. Male anterior urethral stricture​

Labial mucosa was one of the earliest oral-mucosa donor sites for male urethroplasty, predating the widespread adoption of buccal cheek mucosa:[3][4]

  • Dessanti 1995 — first dedicated labial-mucosa series: 12 patients (11 hypospadias, 1 chordee) with labial mucosa alone or combined with bladder mucosa; urethral gap 3.5–13 cm; 1 fistula and 4 mild stenoses at 3–4.5 yr follow-up.[10]
  • Caldamone 1998 — 22 urethral reconstructions with buccal mucosa from either inner cheek or lower lip; 9 complications (2 meatal stenosis, 4 fistula, 3 stricture), all managed successfully.[13]

3. Hypospadias repair (pediatric and adult)​

Labial mucosa has been used extensively for complex hypospadias, particularly in failed prior repairs.

Castagnetti & Rigamonti 2009 — the largest dedicated labial-mucosa graft urethroplasty series:[9]

  • 115 patients (children and adults) — epispadias, hypospadias, urethral stricture
  • Median follow-up 36 months (6–90)
  • Overall success 66%; complications 34% (16% required additional surgery)
  • Tubularized grafts were the single significant predictor of complications (OR 5.86, 95% CI 1.5–23.4 for hypospadias)
  • Complications were unrelated to age, indication, graft length, or stricture level
  • Conclusion: onlay configuration is preferable to tubularized grafts — the central technical principle for LaMG hypospadias reconstruction

4. Vesicovaginal fistula (VVF) repair​

Oral mucosa (including labial) has been used as an interposition graft in VVF repair. Taha 2025 described buccal mucosa as a second layer in vaginal VVF repair in 10 patients — 100% closure at 6 months with no recurrence and no additional morbidity. The authors noted oral mucosa's thick epithelium and thin submucosa are advantageous over Martius flap in harvest simplicity and low morbidity.[14]

5. Vaginal reconstruction (neovagina)​

Oral mucosa (primarily buccal, but applicable to labial) has been used for neovaginal construction in vaginal agenesis (MRKH) and post-surgical / radiation vaginal foreshortening:[15][16][17][18]

  • Wu 2020 — 16 patients with vaginal agenesis; mesh-autologous buccal-mucosa vaginoplasty; all achieved neovagina 8–10 cm; buccal wound healed in 10–14 days.[16]
  • Lin 2003 — 8 patients with MRKH; first reported buccal-mucosa vaginoplasty; well-formed neovagina in all.[17]
  • Grimsby 2014 — buccal-mucosa graft augmentation for post-radiation foreshortened vagina; vaginal length 4.5 → 8 cm permitting pain-free intercourse.[15]
  • van Leeuwen 2019 — 8 patients (cloacal anomalies, DSD, vaginal agenesis, post-surgical stenosis); autologous buccal mucosa for primary and secondary vaginal reconstruction.[18]

Donor-Site Morbidity — vs Buccal (Cheek) Harvest​

The donor-site morbidity profile of labial harvest differs significantly from cheek harvest, primarily because of mental-nerve proximity.

ComplicationLabial (lower lip)Buccal (inner cheek)Significance
Postoperative pain duration (mean)5.9 months1.0 monthp = 0.022
Perioral numbness duration (mean)10.3 months0.85 monthsp = 0.0027
Persistent discomfortMore commonLess commonTrend
Neurosensory deficits (mental nerve)More commonLess commonTrend
Salivary-flow changesMore commonLess commonTrend
Contracture / mouth-opening difficulty5.9%26.3%Cheek worse
Patient satisfaction (adults)50%92%Lip worse
Quality-of-life analog scale1.350.66p = 0.079 (NS)
Long-term perioral sensory defect (> 1 yr, adults)28%LowerAdults > children

Sources: Kamp 2005,[6] Jang 2005,[4] Castagnetti 2008,[19] Markiewicz 2008.[3]

Kamp 2005 — the pivotal donor-site comparison. Lower-lip harvest produced significantly longer pain duration (5.9 vs 1.0 months, p = 0.022) and significantly longer perioral numbness (10.3 vs 0.85 months, p = 0.0027) compared with cheek harvest. Only 50% of lip-harvest patients were satisfied versus 92% of cheek-harvest patients. Based on these results the authors changed their technique entirely from lower lip to inner cheek harvesting, a shift that the broader reconstructive community has largely echoed in adults.[6]

Pediatric exception. Tekin 2025 performed objective neurosensory testing (Semmes-Weinstein monofilaments + thermal discrimination) in 21 pediatric patients after lower-lip harvest (cohort 53 patients, 2000–2023). No patient reported sensory disturbance, oral dysfunction, or cosmetic concerns. Sensory thresholds were identical to age-matched controls (2.21 ± 0.50 vs 2.16 ± 0.39, p > 0.05); all correctly identified thermal stimuli. Lower-lip harvest is safe in children when performed with meticulous technique.[20]

Castagnetti 2008 long-term data — 78 patients (children and adults) at median 7.6 years after oral-mucosa harvest: perioral sensory defect on formal oral-surgeon examination in 28%, but seldom perceived by patients and never required treatment. Significantly more common in adults than children. No other variable (harvest site, graft length, follow-up duration) significantly predicted the deficit.[19]

Practical synthesis. The mental-nerve trade-off is age-dependent and patient-perception-dependent: objective deficits exist but are usually subclinical; the dominant patient-reported issue is prolonged numbness and pain in adults, which is the reason cheek mucosa supplanted lower lip in adult male urethroplasty.

Comparison — Three Oral Mucosal Graft Sites​

FeatureLabial (lower lip)Buccal (inner cheek)Lingual (tongue)
Harvest siteInner lower lipInner cheekVentrolateral tongue
Max single-site length3.5–6 cm6–7 cm9–12 cm
Graft width1.5–2.0 cm1.5–2.5 cm1.0–1.5 cm
Total thicknessSimilarSimilar (~1600 µm)Similar (~1600 µm)
Epithelium / submucosaSimilar to buccalReferenceThinner
Vascular densitySimilarSimilarSimilar
Male-urethroplasty success66% (mixed tube / onlay)80–97.9%82.7–89.7%
Female-urethroplasty success93.5% at 2 yr (n = 204)~90–95%~90–95%
Mental-nerve injury riskYes (significant)NoNo
Stensen's-duct injury riskNoYesNo
Mouth-opening restriction5.9%26.3%0%
Pain duration (mean)5.9 months1.0 monthResolves in weeks
Numbness duration (mean)10.3 months0.85 months7.3% at 12 months
Patient satisfaction (adults)50%92–98.2%Similar to buccal
Pediatric safetySafe (no objective deficits)SafeSafe
Best indicationFemale urethroplasty; supplementary site; pediatricPrimary site for most urethroplastiesDistal urethra / meatus; long grafts

References: Wessells 2023,[1] Jena 2025,[2] Castagnetti 2009,[9] Castagnetti 2008,[19] Jang 2005,[4] Kamp 2005,[6] Tekin 2025,[20] Berg 2024 GURS,[21] Campos-Juanatey 2022,[22] Barbagli 2014.[23]

Advantages​

  • Ease of harvest — straightforward exposure and dissection.[9][10]
  • Less contracture / trismus — only 5.9% contracture vs 26.3% for inner cheek.[4]
  • No Stensen's-duct injury risk — unlike buccal harvest.[3]
  • Safe in pediatric patients — no objective sensory deficits in children on Semmes-Weinstein and thermal testing.[20]
  • Combinable with buccal or lingual mucosa or with the contralateral lip for longer grafts.[10][13]
  • Excellent for female urethroplasty — Jena 2025 n = 204 series, 93.5% success at 2 yr with no significant donor-site morbidity.[2]
  • Identical histological properties to buccal and lingual mucosa.[5][11]

Disadvantages​

  • Mental-nerve injury risk — longer pain (5.9 vs 1.0 mo) and numbness (10.3 vs 0.85 mo) than cheek harvest in adults.[6]
  • Smaller graft area — 3.5–6 cm limits use for long-segment strictures.[1][9]
  • Lower adult patient satisfaction — 50% vs 92% for cheek harvest in Kamp 2005.[6]
  • Tubularization significantly worsens outcomes — OR 5.86 for complications (Castagnetti 2009); onlay strongly preferred.[9]
  • Less commonly used — the 2024 GURS survey found 99% of reconstructive urologists prefer buccal cheek mucosa as the primary harvest site.[21]

When to Choose Labial Mucosa​

ScenarioRationale
Female urethral strictureLargest published series uses LaMG specifically (Jena n = 204, 93.5% at 2 yr)[2]
Pediatric urethral reconstructionSafe with no objective sensory deficits[20][19]
Supplementary graft sourceBuccal insufficient, previously harvested, or diseased (oral submucous fibrosis)[13]
Patient prioritizing avoidance of trismusSignificantly less mouth-opening restriction than cheek harvest (5.9% vs 26.3%)[4]
Short-segment strictureSmaller graft dimensions (3.5–6 cm) sufficient[9]

When to avoid labial mucosa​

  • Long-segment male urethral stricture — insufficient graft length; prefer buccal or lingual mucosa.[1]
  • Adult patients prioritizing donor-site comfort — significantly longer pain and numbness vs cheek.[6]
  • Tubularized graft configurations — significantly higher complication rate (OR 5.86); use onlay instead.[9]

Key Takeaways​

The labial (lower lip) mucosa graft occupies a specific and evolving niche among the three oral-mucosa donor sites. While it has been largely supplanted by buccal cheek mucosa as the primary harvest site for adult male urethroplasty — driven by the cheek's larger graft area, shorter pain and numbness duration, and higher patient satisfaction[6][21] — labial mucosa has its strongest modern application in female urethral stricture repair, where the largest published series (Jena n = 204) demonstrates 93.5% success at 2 years with minimal morbidity.[2] In pediatric patients, objective neurosensory testing confirms lower-lip harvest is safe with no detectable mental-nerve injury when performed meticulously.[20] The central technical principle across all applications is to use the graft as an onlay rather than a tube, since tubularization carries an OR 5.86 for complications.[9] Labial mucosa remains a valuable supplementary donor site when buccal or lingual mucosa is unavailable, insufficient, or previously harvested.

See Also​

References​

1. 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

2. Jena AK, Jena R, Madhavan M, Madhavan K. Dorsal onlay labial mucosal graft urethroplasty in female urethral stricture: outcomes of over 200 cases from a single surgeon. Urology. 2025;published online. doi:10.1016/j.urology.2025.05.040

3. Markiewicz MR, DeSantis JL, Margarone JE, Pogrel MA, Chuang SK. Morbidity associated with oral mucosa harvest for urological reconstruction: an overview. J Oral Maxillofac Surg. 2008;66(4):739–44. doi:10.1016/j.joms.2007.11.023

4. Jang TL, Erickson B, Medendorp A, Gonzalez CM. Comparison of donor site intraoral morbidity after mucosal graft harvesting for urethral reconstruction. Urology. 2005;66(4):716–20. doi:10.1016/j.urology.2005.04.045

5. Duckett JW, Coplen D, Ewalt D, Baskin LS. Buccal mucosal urethral replacement. J Urol. 1995;153(5):1660–3.

6. Kamp S, Knoll T, Osman M, et al. Donor-site morbidity in buccal mucosa urethroplasty: lower lip or inner cheek? BJU Int. 2005;96(4):619–23. doi:10.1111/j.1464-410X.2005.05695.x

7. Won SY, Yang HM, Woo HS, et al. Neuroanastomosis and the innervation territory of the mental nerve. Clin Anat. 2014;27(4):598–602. doi:10.1002/ca.22310

8. Toure G. Mental nerves in the lower lip: anatomical basis for the recovery of sensation following inferior alveolar nerve damage. Plast Reconstr Surg. 2023;152(2):413–20. doi:10.1097/PRS.0000000000010241

9. Castagnetti M, Rigamonti W. Aptness and complications of labial mucosa grafts for the repair of anterior urethral defects in children and adults: single centre experience with 115 cases. World J Urol. 2009;27(6):799–803. doi:10.1007/s00345-009-0401-5

10. Dessanti A, Porcu A, Scanu AM, Dettori G, Caccia G. Labial mucosa and combined labial / bladder mucosa free graft for urethral reconstruction. J Pediatr Surg. 1995;30(11):1554–6. doi:10.1016/0022-3468(95)90155-8

11. Sterling J, Hecksher D, Hayden C, et al. Buccal mucosa — a narrative review: how does it work, how is it used, what is coming next. Urology. 2026;published online. doi:10.1016/j.urology.2026.03.015

12. Soave A, Steurer S, Dahlem R, et al. Histopathological characteristics of buccal mucosa transplants in humans after engraftment to the urethra: a prospective study. J Urol. 2014;192(6):1725–9. doi:10.1016/j.juro.2014.06.089

13. Caldamone AA, Edstrom LE, Koyle MA, Rabinowitz R, Hulbert WC. Buccal mucosal grafts for urethral reconstruction. Urology. 1998;51(5A Suppl):15–9. doi:10.1016/s0090-4295(98)00088-0

14. Taha KM, Mohamed MI, Desoky E, Seleem MM, Fawzi AM. Buccal mucosal graft as a second layer in the vaginal repair of vesicovaginal fistulas. Neurourol Urodyn. 2025;44(2):287–93. doi:10.1002/nau.25657

15. Grimsby GM, Bradshaw K, Baker LA. Autologous buccal mucosa graft augmentation for foreshortened vagina. Obstet Gynecol. 2014;123(5):947–50. doi:10.1097/AOG.0000000000000226

16. Wu M, Wang Y, Xu J, et al. Vaginoplasty with mesh autologous buccal mucosa in vaginal agenesis: a multidisciplinary approach and literature review. Aesthet Surg J. 2020;40(12):NP694–NP702. doi:10.1093/asj/sjaa147

17. Lin WC, Chang CY, Shen YY, Tsai HD. Use of autologous buccal mucosa for vaginoplasty: a study of eight cases. Hum Reprod. 2003;18(3):604–7. doi:10.1093/humrep/deg095

18. van Leeuwen K, Baker L, Grimsby G. Autologous buccal mucosa graft for primary and secondary reconstruction of vaginal anomalies. Semin Pediatr Surg. 2019;28(5):150843. doi:10.1016/j.sempedsurg.2019.150843

19. Castagnetti M, Ghirardo V, Capizzi A, Andretta M, Rigamonti W. Donor site outcome after oral mucosa harvest for urethroplasty in children and adults. J Urol. 2008;180(6):2624–8. doi:10.1016/j.juro.2008.08.053

20. Tekin A, Tiryaki S, Avcı D, Ulman İ. Lower lip complications: myth or reality? A case-control study on sensory outcomes after buccal mucosa grafting. Urology. 2025;published online. doi:10.1016/j.urology.2025.06.061

21. 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;191:139–43. doi:10.1016/j.urology.2024.06.019

22. Campos-Juanatey F, Azueta Etxebarria A, Calleja Hermosa P, et al. Histological comparison of buccal and lingual mucosa grafts for urethroplasty: do they share tissue structures and vascular supply? J Clin Med. 2022;11(7):2064. doi:10.3390/jcm11072064

23. Barbagli G, Fossati N, Sansalone S, et al. Prediction of early and late complications after oral mucosal graft harvesting: multivariable analysis from a cohort of 553 consecutive patients. J Urol. 2014;191(3):688–93. doi:10.1016/j.juro.2013.09.006