Skip to main content

Lingual Mucosa Graft (LMG)

The lingual mucosa graft (LMG) is a free mucosal graft harvested from the ventrolateral surface of the tongue, first described by Simonato and colleagues in 2006 as an alternative to buccal mucosa for substitution urethroplasty. The AUA Urethral Stricture Disease Guideline (2023) issues a Strong Recommendation (Evidence Grade A) that surgeons may use buccal or lingual mucosal grafts as equivalent alternatives, anchored on a meta-analysis of 12 studies showing no difference in success (RR for LMG 1.03; 95% CI 0.96–1.10). The same guideline notes that LMG is thinner than buccal mucosa, which may be advantageous for distal urethral and meatal reconstruction by causing less luminal restriction.[1][2][3]

See the overview article for graft selection principles: Grafts in GU Reconstruction, the anatomy article: The Oral Cavity, and the companion graft hub: Buccal Mucosa Graft (BMG).

Historical Context​

Use of oral mucosa for urethroplasty dates to the 1990s, with buccal mucosa rapidly establishing itself as the gold-standard graft material. Simonato 2006 first reported the tongue as an alternative donor site in 8 patients, demonstrating feasibility, ease of harvest, and less postoperative pain than buccal mucosa.[3] Kumar 2007 / 2008 then published the first large series and detailed harvest-technique descriptions from India,[4][5] and Xu 2011 reported the first dedicated 110-patient long-term donor-site morbidity series.[6]

Anatomy and Histological Properties​

Harvest site. The graft is taken from the lateral mucosal lining of the tongue (ventrolateral surface), deliberately avoiding:

  • The dorsum — keratinized papillae are unsuitable for grafting
  • The ventral midline — lies over the lingual frenulum and major neurovascular structures[4][5]

Blood supply. The tongue is supplied by the lingual artery (branch of the external carotid). The ventral surface is supplied by the sublingual artery, while the body is nourished by approximately 25 branches from the deep lingual artery. The two vascular halves are separated by the lingual septum, with only occasional arterial anastomoses crossing the midline — which permits safe unilateral harvest without compromising the contralateral half.[7][8]

Innervation. General sensation to the anterior two-thirds is via the lingual nerve (V3), and taste via the chorda tympani (CN VII). The lingual nerve gives off terminal branches at the anterior border of hyoglossus, with primary trunks on the outer surface of genioglossus. Thin branches supply the ventral mucosa, while 4–9 thicker secondary trunks follow translingual courses to the dorsum.[9][10] Submucosal-plane harvest preserves these deeper trunks but cannot fully avoid the superficial ventral branches — the anatomic substrate for transient tongue numbness.

Histological comparison — LMG vs BMG​

The only prospective histological comparison (Campos-Juanatey 2022, 57 grafts from 33 urethroplasties) found:[11]

FeatureLMGBMGSignificance
Total graft thicknessMedian ~1599 µmMedian ~1599 µmNot significant
Epithelium layerThinnerThickerp < 0.05
Submucosa layerThinnerThickerp < 0.05
Muscular layerThickerThinnerp < 0.05
Vascular densitySimilarSimilarNot significant
Vascular areaSimilarSimilarNot significant
Adipose tissueLessMorep < 0.05
Graft dimensionsLonger and narrowerShorter and widerp < 0.05

Practical synthesis. Despite identical overall thickness and vascular supply, LMG has a thinner epithelium and submucosa, a thicker muscular layer, and less adipose tissue than BMG. The thinner mucosal layers explain the clinical observation that LMG causes less luminal restriction, particularly in distal urethral and meatal reconstruction.[1][11]

Properties that make oral mucosa ideal for urethroplasty (shared by both LMG and BMG):

  • Non-keratinized stratified squamous epithelium (similar to urethral epithelium)
  • Thick epithelium resistant to mechanical stress
  • Thin, highly vascular lamina propria — rapid imbibition and inosculation
  • Resistant to infection in a wet environment
  • Compatible with the urinary milieu
  • Easy to harvest with minimal long-term donor-site morbidity[2]

Harvest Technique​

The technique as described by Kumar 2008 and refined by Xu 2017:[4][12]

  1. Anesthesia — general anesthesia, preferably with nasotracheal intubation to maximize oral access (orotracheal intubation acceptable). Tongue retracted with a Babcock clamp or stay sutures.
  2. Tongue exposure — tongue retracted to the contralateral side, exposing the ventrolateral surface; mouth gag or tongue depressor maintains exposure.
  3. Graft marking — outline on the lateral mucosal lining, starting posteriorly. Boundaries:
    • Medially — lateral to the ventral midline veins and lingual frenulum
    • Laterally — the lateral border of the tongue
    • Posteriorly — at the junction of the anterior two-thirds and posterior one-third
    • Anteriorly — can extend across the tip to the contralateral side if a longer graft is needed
  4. Graft dimensions:
    • Single-side harvest — up to 9–12 cm in length[12]
    • Bilateral harvest (across the tip) — up to 16–20 cm in length[5][12]
    • Width — typically 1.0–2.0 cm[4][11]
  5. Harvest — submucosal-plane sharp dissection. The graft includes epithelium, lamina propria, and a thin layer of submucosa but no muscle.
  6. Graft preparation — placed in saline; excess submucosal tissue and fat trimmed from the deep surface; tailored to the urethral defect.
  7. Donor-site closure — continuous running 4-0 polyglactin (Vicryl) sutures for immediate hemostasis. Mean harvest time approximately 18 minutes.[4]
  8. Postoperative care — oral fluids within 24 h; soft diet at 48–72 h; normal diet at 4–5 days.[4][5]

Applications in Urology and Urogynecology​

1. Male anterior urethral stricture — primary indication​

LMG is used in all the same configurations as BMG for substitution urethroplasty:[2]

  • Dorsal onlay (Barbagli technique) — most common for bulbar strictures
  • Ventral onlay — alternative for bulbar strictures
  • Dorsal inlay with ventral sagittal urethrotomy (Asopa technique) — for penile strictures
  • Dorsolateral onlay with one-sided urethral dissection (Kulkarni technique) — for penile and panurethral strictures
  • Two-sided dorsal + ventral onlay (Palminteri technique) — for obliterative bulbar strictures
  • Augmented anastomotic urethroplasty — for near-obliterative segments
SeriesnStricture lengthTechniqueFollow-upSuccess
Simonato 2006 (pilot)[3]81.5–4.5 cmDorsal onlay22 mo87.5%
Simonato 2008[13]29Mean 3.6 cmDorsal onlay (one-stage) + two-stage17.7 mo81.8–100% (bulbar / penile); 60% bulbopenile
Xu 2017 (long segment)[12]81Mean 12.1 cm (8–20)Long-strip LMG ± BMG41 mo82.7%
Lumen 2016 (prospective LMG vs BMG)[14]29 LMG vs 29 BMGVariousVarious30 moLMG 89.7% vs BMG 82.8% (p = 0.306)
Aldaqadossi 2020 (lichen sclerosus)[15]34Long segmentDorsal onlay66.5 mo88.2%

2. Long-segment and panurethral strictures​

LMG has a unique advantage for long-segment (≥ 8 cm) strictures: a single ventrolateral tongue harvest can provide grafts up to 12 cm, and bilateral harvest across the tip can yield up to 16–20 cm — often longer than what a single buccal cheek can provide.[12][5]

Xu 2017 — the largest long-segment LMG series (81 patients, mean stricture length 12.1 cm):[12]

  • Single 9–12 cm LMG: 52 patients
  • LMG > 12 cm: 17 patients
  • LMG + BMG combined: 12 patients (when bilateral tongue harvest was insufficient for very long defects)
  • Overall success 82.7% at 41-month mean follow-up
  • Stricture recurrence in 10 (12.3%); urethrocutaneous fistula in 4 (4.9%)

For panurethral strictures, a 2024 GURS survey found that 90% of reconstructive urologists prefer multiple BMGs over a combined graft / flap approach, with 56% preferring both cheeks when harvesting long grafts. LMG provides an additional donor site when bilateral buccal harvest is insufficient or when buccal mucosa is unavailable.[16]

3. Lichen sclerosus (LS)-associated strictures​

LMG is particularly valuable for LS-associated strictures because oral mucosa is resistant to LS recurrence (unlike penile skin grafts).

Aldaqadossi 2020 — the longest dedicated follow-up of LMG in LS strictures:[15]

  • 34 patients with LS-associated long anterior urethral strictures
  • Dorsal onlay LMG urethroplasty
  • Median follow-up 66.5 months (> 5 years)
  • Success 88.2%; all failures within the first year
  • Sustained improvement in Qmax and IPSS through 5 years
  • Oral complications mild and early only — no long-term oral morbidity

4. Failed hypospadias repair​

LMG has been used extensively in failed hypospadias surgery, where local penile skin is often scarred and insufficient.

  • Li 2016 — 56 patients with failed hypospadias repairs (one-stage onlay LMG in 42, one-stage modified-Snodgrass inlay LMG in 14); median graft length 5.6 cm (4–13 cm); mean follow-up 34.7 mo. Fistula 12.5%; stricture 8.9%; overall success 78.6%.[17]
  • Hongyong 2017 — 62 pre-pubertal boys with failed hypospadias (33 LMG vs 29 BMG): LMG success 84.8% vs BMG 83.0% (p > 0.05); complications LMG 15.0% vs BMG 17.0% (p > 0.05). No significant differences in peak flow, HOSE scores, or complication rates — LMG and BMG are equivalent for failed hypospadias repair in children.[18]

5. Female urethral stricture​

LMG has been studied specifically for female urethral stricture using the dorsal onlay technique.

  • Sharma 2010 — first dedicated LMG series for female urethral stricture: 15 women, mean age 42, recurrent strictures after multiple dilations / urethrotomies. Dorsal onlay LMG urethroplasty via suprameatal inverted-U incision. Preoperative Qmax 7.2 mL/s → postoperative 29.87 mL/s at 3 mo, sustained at 12 mo. Submeatal stenosis requiring dilation in 1 (6.7%); no urinary incontinence; no long-term donor morbidity.[19]
  • Richard 2021 — 19 women with dorsal onlay oral (buccal or lingual) mucosa urethroplasty: clinical success 94.7% at 1–3 mo and 90.9% at 1 yr; recurrence 5.3%; Qmax 7.4 → 15.2 mL/s (p = 0.008); de novo SUI 15.7% at 1–3 mo and 9.1% at 1 yr.[20]

6. Distal urethral and meatal reconstruction​

The AUA guideline specifically notes that LMG's thinner profile may provide an advantage in distal urethral and meatal reconstruction by causing less luminal restriction than BMG.[1] Indications include:

  • Meatoplasty
  • Distal penile urethroplasty
  • Fossa navicularis reconstruction

Donor-Site Morbidity — Detailed Analysis​

Donor-site morbidity is the most clinically relevant differentiator between LMG and BMG. The evidence reveals a distinct temporal pattern of complications.

Early postoperative period (Days 1–3) — Lumen 2016 prospective comparison​

ComplicationLMGBMGSignificance
Pain (NRS, Day 3)64Not significant
Severe difficulty eating / drinking (Day 3)62.1%24.1%p = 0.004
Severe difficulty speaking (Day 3)93.1%55.2%p = 0.001
Dysgeusia (Day 3)48.3%13.8%p = 0.01
Slurring of speech (Day 1)[4][5]20–24%——
Donor-site pain (Day 1)[4][5]90–92%——

Intermediate (2 weeks)​

ComplicationLMGBMGSignificance
Speech impairment55.2%13.8%p = 0.002
Oral tightness6.9%41.4%p = 0.005
Pain (NRS)32Not significant

Long-term (6 months)​

ComplicationLMGBMGSignificance
Sensitivity disorders31%44.8%Not significant (p = 0.279)
Pain (NRS)00Not significant

≥ 12 months — Xu 2011 (n = 110)[6]​

  • Tongue numbness 7.29% (down from 17.27% at 6 mo)
  • Parageusia 3.13% (down from 5.45% at 6 mo)
  • Slurred speech 3.13% (down from 8.18% at 6 mo)
  • Fine-motor tongue difficulty at 12 mo 6.2% (Xu 2017, n = 81)[12]

Key pattern. LMG causes more early oral morbidity than BMG in the first 2 weeks (speech, eating, dysgeusia), while BMG causes more oral tightness (from cheek scarring). By 6 months, long-term morbidity converges and is not statistically different between the two grafts. Most LMG complications resolve within the first year.[14][6]

LMG vs BMG — Comprehensive Comparison​

FeatureLingual Mucosa Graft (LMG)Buccal Mucosa Graft (BMG)
Harvest siteVentrolateral tongueInner cheek
Maximum single-site length9–12 cm (one side); 16–20 cm (bilateral across tip)6–7 cm (one cheek); 12–14 cm (both cheeks)
Graft width1.0–1.5 cm (narrower)1.5–2.5 cm (wider)
Total graft thickness~1600 µm~1600 µm
Epithelium / submucosaThinnerThicker
Muscular layerThickerThinner
Adipose tissueLessMore
Vascular densitySimilarSimilar
Urethroplasty success82.7–89.7%82.8–97.9%
Meta-analysisRR 1.03 (95% CI 0.96–1.10) — no differenceReference
Early oral pain (Day 3)NRS 6NRS 4 (NS)
Early speech difficulty93.1% (Day 3)55.2% (Day 3) — p = 0.001
Early eating difficulty62.1% (Day 3)24.1% (Day 3) — p = 0.004
Oral tightness (2 wk)6.9%41.4% — p = 0.005
Long-term sensitivity (6 mo)31%44.8% (NS)
Advantage for distal urethra / meatusYes (thinner — less luminal restriction)No
Advantage for long graftsYes (longer single-site harvest)No
Mouth-opening restrictionNoPossible
Salivary-duct injury riskNoneStensen's duct
Surgeon preference (GURS 2024)1% primary site99% primary site

Advantages of LMG Over BMG​

  1. Thinner graft — less luminal restriction, particularly advantageous for distal urethral and meatal reconstruction.[1][11]
  2. Longer single-site harvest — up to 12 cm from one side vs ~7 cm from one cheek; bilateral tip harvest up to 20 cm.[12][5]
  3. No risk of Stensen's duct injury — buccal harvest carries a parotid-duct injury risk.[2]
  4. No mouth-opening restriction — only 6.9% at 2 weeks vs 41.4% for BMG.[14]
  5. Less adipose tissue — cleaner graft, less defatting required.[11]
  6. Additional donor site — combinable with BMG when very long (> 12 cm) grafts are needed.[12]
  7. Equivalent success rates — meta-analysis confirms no urethroplasty-outcome difference.[1]

Disadvantages of LMG vs BMG​

  1. More early oral morbidity — significantly more speech difficulty, eating difficulty, and dysgeusia in the first 2 weeks.[14]
  2. Narrower graft — limits use when a wide graft is needed.[11]
  3. Tongue numbness — 7.3% at 12 months (lingual-nerve branch injury).[6]
  4. Less familiar to most reconstructive urologists — 99% of GURS members prefer buccal mucosa as the primary harvest site.[16]
  5. More technically challenging — the tongue is mobile and exposure can be harder to maintain than for the cheek.[2]

When to Choose LMG Over BMG​

ScenarioRationale
Distal urethral / meatal strictureThinner graft causes less luminal restriction[1]
Long-segment stricture (> 7 cm)Single buccal cheek often insufficient; single-side LMG up to 12 cm[12]
Panurethral strictureLMG + bilateral BMG can yield > 25 cm of total graft[12]
Prior buccal harvestBuccal mucosa already used and unavailable[2]
Buccal pathologySubmucous fibrosis, leukoplakia, or other buccal disease[2]
Trismus is a major concernLMG does not cause cheek-scarring oral tightness[14]

Current Practice Patterns​

Despite equivalent outcomes, buccal mucosa remains overwhelmingly preferred in current practice. The 2024 GURS survey found that 99% of reconstructive urologists prefer buccal mucosa as the primary harvest site, with lingual mucosa used primarily as a secondary or supplementary source.[16] This preference reflects greater familiarity, wider graft dimensions, and less early postoperative oral morbidity.

Key Takeaways​

The lingual mucosa graft is a validated, AUA guideline-endorsed equivalent alternative to buccal mucosa for substitution urethroplasty, with identical success rates (RR 1.03, 95% CI 0.96–1.10) across all indications.[1] Its thinner epithelium and submucosa make it particularly advantageous for distal urethral and meatal reconstruction, while its ability to provide longer single-site grafts (up to 12 cm unilateral, 20 cm bilateral) makes it valuable for long-segment and panurethral strictures.[12][11] The trade-off is more early oral morbidity (speech and eating difficulty in the first 2 weeks) compared with buccal mucosa, though long-term donor-site outcomes are equivalent.[14] Most oral complications resolve within the first year, with residual tongue numbness in 7.3% and parageusia in 3.1% at 12 months.[6] In contemporary practice, LMG serves primarily as a supplementary donor site when buccal mucosa is insufficient, unavailable, or when the thinner graft profile is specifically desired.[16]

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. Horiguchi A. Substitution urethroplasty using oral mucosa graft for male anterior urethral stricture disease: current topics and reviews. Int J Urol. 2017;24(7):493–503. doi:10.1111/iju.13356

3. Simonato A, Gregori A, Lissiani A, et al. The tongue as an alternative donor site for graft urethroplasty: a pilot study. J Urol. 2006;175(2):589–92. doi:10.1016/S0022-5347(05)00166-7

4. Kumar A, Das SK, Sharma GK, et al. Lingual mucosal graft substitution urethroplasty for anterior urethral strictures: our technique of graft harvesting. World J Urol. 2008;26(3):275–80. doi:10.1007/s00345-008-0255-2

5. Kumar A, Goyal NK, Das SK, et al. Oral complications after lingual mucosal graft harvest for urethroplasty. ANZ J Surg. 2007;77(11):970–3. doi:10.1111/j.1445-2197.2007.04292.x

6. Xu YM, Xu QK, Fu Q, et al. Oral complications after lingual mucosal graft harvesting for urethroplasty in 110 cases. BJU Int. 2011;108(1):140–5. doi:10.1111/j.1464-410X.2010.09852.x

7. Lopez R, Lauwers F, Paoli JR, Boutault F, Guitard J. Vascular territories of the tongue: anatomical study and clinical applications. Surg Radiol Anat. 2007;29(3):239–44. doi:10.1007/s00276-007-0202-8

8. Shangkuan H, Xinghai W, Zengxing W, et al. Anatomic bases of tongue flaps. Surg Radiol Anat. 1998;20(2):83–8. doi:10.1007/BF01628906

9. Rusu MC, Nimigean V, Podoleanu L, Ivaşcu RV, Niculescu MC. Details of the intralingual topography and morphology of the lingual nerve. Int J Oral Maxillofac Surg. 2008;37(9):835–9. doi:10.1016/j.ijom.2008.05.014

10. Yang HM, Woo YJ, Won SY, et al. Course and distribution of the lingual nerve in the ventral tongue region: anatomical considerations for frenectomy. J Craniofac Surg. 2009;20(5):1359–63. doi:10.1097/SCS.0b013e3181ae42fa

11. 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

12. Xu YM, Li C, Xie H, et al. Intermediate-term outcomes and complications of long segment urethroplasty with lingual mucosa grafts. J Urol. 2017;198(2):401–6. doi:10.1016/j.juro.2017.03.045

13. Simonato A, Gregori A, Ambruosi C, et al. Lingual mucosal graft urethroplasty for anterior urethral reconstruction. Eur Urol. 2008;54(1):79–85. doi:10.1016/j.eururo.2008.01.023

14. Lumen N, Vierstraete-Verlinde S, Oosterlinck W, et al. Buccal versus lingual mucosa graft in anterior urethroplasty: a prospective comparison of surgical outcome and donor site morbidity. J Urol. 2016;195(1):112–7. doi:10.1016/j.juro.2015.07.098

15. Aldaqadossi HA, Eladawy M, Shaker H, et al. Dorsal onlay urethroplasty using lingual mucosal grafts for lichen sclerosis anterior urethral strictures repair: long-term outcomes. Int J Urol. 2020;27(4):320–5. doi:10.1111/iju.14187

16. 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

17. Li HB, Xu YM, Fu Q, et al. One-stage dorsal lingual mucosal graft urethroplasty for the treatment of failed hypospadias repair. Asian J Androl. 2016;18(3):467–70. doi:10.4103/1008-682X.157545

18. Hongyong J, Shuzhu C, Min W, Weijing Y, Yidong L. Comparison of lingual mucosa and buccal mucosa grafts used in inlay urethroplasty in failed hypospadias of pre-pubertal boys in a Chinese group. PLoS One. 2017;12(8):e0182803. doi:10.1371/journal.pone.0182803

19. Sharma GK, Pandey A, Bansal H, et al. Dorsal onlay lingual mucosal graft urethroplasty for urethral strictures in women. BJU Int. 2010;105(9):1309–12. doi:10.1111/j.1464-410X.2009.08951.x

20. Richard C, Peyronnet B, Drain A, et al. Dorsal onlay oral mucosa graft urethroplasty for female urethral stricture. Urology. 2021;158:215–21. doi:10.1016/j.urology.2021.09.001