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The Oral Cavity

For the reconstructive urologist, the mouth is not an organ system to understand — it is a graft bed. Oral mucosa is the preferred substitution material for urethroplasty, endorsed by the AUA as the first-choice graft for anterior urethral stricture disease.[1] Three donor sites are in routine use — buccal (inner cheek), lingual (ventrolateral tongue), and labial (inner lower lip) — and each has histologic, vascular, and morbidity characteristics that determine where and how it is used. This article covers the anatomy that matters at harvest and the trade-offs that drive site selection.

See also: Male Urethra, The Leg & Thigh (gracilis flap for long-segment coverage).

Why Oral Mucosa Works​

Oral mucosa transplanted to the urethra retains its native histologic identity — it does not undergo urothelial metaplasia, even after prolonged urine exposure (mean 22.2 months in human biopsy studies).[4] The preserved tissue architecture — thick nonkeratinized stratified squamous epithelium over a richly vascularized submucosa — is what distinguishes it from skin-based grafts and likely explains superior long-term patency.

Three properties drive its success as a urethral graft:

  • Robust submucosal vascular plexus. After engraftment, buccal mucosa supports 94.3 ± 6.4 vessels per 200× field vs 61.7 ± 6.4 for penile skin — a measurable angiogenic advantage.[5]
  • Fetal-like ("scarless") wound healing phenotype. Rapid re-epithelialization, tightly controlled fibroblast activity, and a dampened inflammatory profile.[6]
  • Wet-environment tolerance. Evolved for constant moisture exposure, which maps directly onto intraluminal urinary conditions.

These traits, not surgical tradition, are why buccal mucosa became the standard graft.

Buccal Mucosa​

Surgical Anatomy​

The buccal mucosa lines the inner cheek from the oral commissure anteriorly to the retromolar trigone posteriorly, bounded superiorly and inferiorly by the gingivobuccal sulci. The parotid (Stensen's) duct opens opposite the second maxillary molar and must be identified and preserved during harvest — injury produces salivary fistula or stricture.

Typical single-cheek graft dimensions are 5–6 cm in length by 1.5–2 cm in width. For long-segment reconstruction, 56% of reconstructive urologists harvest bilaterally to obtain adequate tissue, yielding combined graft lengths of 10–12 cm.[3]

Histology​

Median total graft thickness is 1598.9 μm (IQR 1200–2100 μm), layered as follows:[2]

LayerThickness
Epithelium (stratified nonkeratinized squamous)Mean 510 μm (SD 224 μm)
SubmucosaMedian 654 μm (IQR 378–943)
Muscular layerMedian 478 μm (IQR 286–772)
Vascular areaMedian 5% (IQR 5–10%)
Adipose tissueMedian 5% (IQR 0–20%)

The prominent stratum spinosum and thick submucosa give the buccal graft its characteristic handling properties — it rolls and inset-sutures well and resists tearing.

Vascular Supply​

Arterial inflow is from the buccal artery (branch of the maxillary) and the facial artery, feeding a dense submucosal plexus. This plexus is the functional unit that inosculates with the recipient urethral bed and drives graft take.

Innervation​

Sensory innervation comes from the buccal branch of the mandibular division of the trigeminal nerve (CN V₃) — distinct from the motor buccal branch of the facial nerve (CN VII) that lies in the cheek musculature. The dense sensory supply explains the predictable early postoperative donor-site pain.

Lingual Mucosa​

Surgical Anatomy​

Lingual mucosa is harvested from the ventrolateral (undersurface) aspect of the tongue, bounded medially by the lingual frenulum and laterally by the tongue's lateral border. The submandibular (Wharton's) duct opens at the base of the frenulum and must be avoided.

The lingual donor site offers the reconstructive urologist's longest single-strip graft: routine 9–12 cm, with reported maxima up to 20 cm.[7] Mean graft dimensions in comparative series are approximately 5.8 cm × 1.7 cm when matched to defect size, with the natural geometry favoring long-and-narrow over wide rectangles.[2]

Histology​

Total thickness approximates buccal (~1600 μm), but the layer distribution differs significantly:[2]

  • Thinner epithelium and submucosa than buccal mucosa (statistically significant on matched comparison).
  • Less adipose tissue than buccal.
  • Equivalent vascular density and vascular area (median 5% vascular area, IQR 5–10%).

The thinner profile is clinically useful — lingual mucosa lies flatter and is preferred by some surgeons for the distal urethra and meatus, where bulk from a thicker buccal graft is undesirable.

Vascular Supply​

The tongue is supplied by the lingual artery (external carotid branch), dividing into:

  • Deep lingual artery — body of tongue
  • Sublingual artery — floor of mouth and ventral surface
  • Dorsal lingual branches — posterior tongue

The ventrolateral donor site draws principally from the sublingual and deep lingual contributions.

Innervation​

The ventral tongue is innervated by:

  • Lingual nerve (CN V₃) — general sensation
  • Chorda tympani (CN VII, running with the lingual nerve) — taste to the anterior two-thirds

This dual supply explains the substantially higher rate of dysgeusia with lingual harvest (48.3% vs 13.8% at day 3 vs buccal, p=0.01).[8]

Clinical Outcomes​

A meta-analysis of 12 studies found no difference in urethroplasty success rates between buccal and lingual grafts (RR 1.03, 95% CI 0.96–1.10).[1] In a large series of 81 long-segment strictures (mean 12.1 cm), lingual mucosa urethroplasty achieved an 82.7% success rate at mean 41-month follow-up.[7]

Labial Mucosa​

Surgical Anatomy​

Labial mucosa is harvested from the inner surface of the upper or lower lip, from the oral commissure to the midline. Graft area is limited — typically 3.5–6 cm in usable length — which confines labial mucosa to short-defect or pediatric reconstruction.[9]

Histology​

Histologically similar to buccal mucosa (stratified nonkeratinized squamous epithelium over vascular submucosa), but the anatomic constraint of lip width limits graft size, making labial a secondary choice when buccal or lingual are unavailable.[1]

Vascular Supply​

The lips are supplied by the superior and inferior labial arteries, branches of the facial artery, which form rich submucosal anastomoses. Vascularization is adequate for graft survival.

Innervation​

  • Upper lip — infraorbital nerve (CN V₂)
  • Lower lip — mental nerve (CN V₃)

Both are sensory branches of the trigeminal nerve.

Clinical Use​

Labial mucosa is rarely used in contemporary practice — 99% of reconstructive urologists prefer buccal as first choice.[3] Historical niche applications include pediatric hypospadias repair and combined labial/bladder mucosa grafts for posterior hypospadias with urethral gaps of 6–13 cm.[9]

Graft Selection — Site-Specific Anatomy Drives the Choice​

CharacteristicBuccalLingualLabial
Max single-strip length5–6 cm (bilateral: 10–12 cm)9–20 cm3.5–6 cm
Epithelium/submucosaThickerThinnerSimilar to buccal
Vascular area~5%~5%Adequate
Adipose contentMedian 5% (IQR 0–20%)Significantly lessSimilar to buccal
Reported success80–90%82.7–89.7%Limited data
Contemporary use99% first choiceLong-segment alternativeRarely used

By Stricture Location[3][10]​

  • Bulbar — buccal or lingual equivalent; dorsal onlay preferred by 66% of surgeons.
  • Penile — buccal preferred by 95%; lingual's thinner profile is favored at the distal urethra / meatus where graft bulk is a liability.
  • Long-segment (≥8 cm) — lingual, for single-strip harvest up to 20 cm.
  • Panurethral — multiple buccal grafts preferred by 90% of surgeons over combined graft/flap approaches.

Donor-Site Morbidity​

Because graft site selection is as much a morbidity decision as an anatomic one, these numbers shape the informed-consent conversation.

Buccal Harvest​

Complication rate in prospective series: 12.5% overall.[11]

  • Bleeding — 5%
  • Infection — 2.5%
  • Hypergranulation — 2.5%
  • Long-term limited mouth opening — 7.5%
  • Oral tightness at 2 weeks — 41.4%

Pain trajectory: peaks at 1 week (70% of patients), pain-free by 3 months in 87.5%. Median NRS scores: day 3 = 4, 2 weeks = 2, 6 months = 0.[8][11] No statistically significant decrease in overall oral health at 3 or 6 months.[11]

Long-term: 44.8% report some residual oral sensitivity disorder at 6+ months, typically mild.[8]

Lingual Harvest​

More early morbidity, similar long-term outcomes.[8]

Day 3:

  • Severe eating/drinking difficulty — 62.1% (vs 24.1% buccal, p=0.004)
  • Speech impairment — 93.1% (vs 55.2% buccal, p=0.001)
  • Dysgeusia — 48.3% (vs 13.8% buccal, p=0.01)

2 weeks:

  • Speech impairment — 55.2% (vs 13.8% buccal, p=0.002)
  • Oral tightness — 6.9% (vs 41.4% buccal, p=0.005) — lower with lingual

12 months:

  • Minimal difficulty with fine tongue motor movement — 6.2%[7]
  • Sensitivity disorders — 31% (vs 44.8% buccal, p=0.279)[8]

Pain trajectory: median NRS day 3 = 6 (higher than buccal, not statistically significant), 2 weeks = 3, 6 months = 0.

Closure vs Nonclosure of the Buccal Donor Site​

A randomized controlled trial of 135 patients found nonclosure noninferior to closure with respect to intensity and quality of oral pain.[12] Either approach is acceptable; surgeon preference and bleeding profile drive the decision.

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. 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

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. 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

5. Gardikis S, Giatromanolaki A, Ypsilantis P, et al. "Comparison of Angiogenic Activities After Urethral Reconstruction Using Free Grafts in Rabbits." Eur Urol. 2005;47(3):417–21. doi:10.1016/j.eururo.2004.10.014

6. 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;S0090-4295(26)00169-X. doi:10.1016/j.urology.2026.03.015

7. 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):401–406. doi:10.1016/j.juro.2017.03.045

8. 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

9. 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

10. 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

11. Desai D, Joshi S, Ravichandran K, et al. "Donor Site Morbidity and Impact on Oral Health Following Buccal Mucosal Graft Harvesting for Urethroplasty: A Prospective Study." World J Urol. 2025;43(1):531. doi:10.1007/s00345-025-05898-6

12. Soave A, Dahlem R, Pinnschmidt HO, et al. "Substitution Urethroplasty With Closure Versus Nonclosure of the Buccal Mucosa Graft Harvest Site: A Randomized Controlled Trial With a Detailed Analysis of Oral Pain and Morbidity." Eur Urol. 2018;73(6):910–922. doi:10.1016/j.eururo.2017.11.014