Buccal Mucosal Graft Urethroplasty for Complex Hypospadias: What the Evidence Tells Us
Introduction: A Surgical Challenge With a Biological Solution
Hypospadias — a congenital condition in which the urethral opening forms on the underside of the penis rather than at its tip — affects approximately 1 in 200 to 1 in 300 male births, making it one of the most common urological birth defects worldwide. For most boys, a single corrective procedure during early childhood is sufficient. But for a significant subset, the situation is far more complicated: proximal or severe hypospadias, failed prior repairs, extensive scarring, and deficient local tissue all conspire to make urethral reconstruction a genuine surgical challenge.
In these complex cases, surgeons need a graft material that is reliable, durable, well-tolerated by the body, and easy to harvest. Over the past three decades, buccal mucosa — the moist inner lining of the cheeks and lips — has emerged as the leading tissue of choice. Understanding how buccal mucosal graft (BMG) urethroplasty works, what outcomes patients and families can realistically expect, and how surgical technique influences success is essential for anyone navigating this difficult terrain.
What Makes Complex Hypospadias Different?
Defining “Complex”
Not all hypospadias repairs are equal in difficulty. Surgeons generally classify a hypospadias case as “complex” when one or more of the following features are present:
- Proximal location of the urethral meatus (perineal, scrotal, or penoscrotal) — requiring a longer urethral reconstruction
- Chordee (downward curvature of the penis) requiring correction alongside urethral repair
- Failed previous urethroplasty — scar tissue, fistulae, or strictures from prior surgery deplete the local tissue available for reconstruction
- Deficient or scarred ventral skin — leaving no reliable local flap material
- Lichen sclerosus affecting penile skin, which rules out using local skin as graft materialNow let me write the full article with inline visuals.
Why Buccal Mucosa? The Ideal Graft Material
The inner lining of the cheek and lower lip has a set of biological properties that make it almost uniquely suited to urethral reconstruction. Buccal mucosa is a non-keratinizing stratified squamous epithelium phenotypically similar to the penile and glandular urethra. This tissue similarity is not cosmetic — it means the graft behaves more like native urethral tissue once transplanted.
An ideal graft tissue requires wide availability with minimal harvest site morbidity, the ability to take to a vascular bed, and ease of replication and harvest. A buccal mucosal graft meets these criteria: the epithelium is thick with high elastic fiber content, the lamina propria is thin, and there is wide availability with ease of harvest.
The mouth heals rapidly and tolerates minor tissue loss well. Most patients experience no lasting complications at the harvest site, making it ethically straightforward to use in children as well as adults.
Surgical Techniques: One Stage or Two?
The Onlay Approach
The most commonly used technique applies the buccal mucosal graft as an onlay — the existing urethral plate is preserved and incised, and the graft is sutured onto it to widen the urethral lumen. This technique is favored when some native urethral plate tissue is intact and healthy enough to serve as a bed for the graft.
After the graft is taken from the lower lip, with possible extension to the inner cheek, complete thinning of the graft is performed. The graft is then sutured in an onlay fashion to the urethral plate, and suprapubic urinary diversion is carried out for several weeks.
The Tubularized Approach
When the urethral defect is too extensive for an onlay — typically when there is no usable urethral plate at all — the graft is rolled into a tube to replace the entire urethral segment. In a published series of 16 complex hypospadias cases, onlay grafts were used in 8 cases and tubularized grafts were used for the others. The tubularized approach carries higher complication rates and is generally reserved for the most severe cases.
Two-Stage Repair
For the most challenging reconstructions — extensive scarring, multiple failed prior surgeries, or insufficient tissue coverage — a staged approach offers advantages. In the first stage, residual fibrosis is released, the glans is split, and the buccal mucosa graft is sutured to the ventral surface of the penis to form a future urethral plate. Second stage reconstruction is performed after 6 months with interposed scrotal dartos tissue.
A long-standing debate revolves around the optimal timing for graft placement — during the initial or subsequent stage. Notably, placing buccal mucosa grafts during the first stage carries a risk of graft shrinkage, potentially up to 30%, due to exposure to air.
What Do the Outcomes Look Like?
Success Rates Across the Literature
The published evidence on BMG urethroplasty for complex hypospadias spans several decades and dozens of studies. The overall picture is broadly positive, though complication rates vary considerably depending on case complexity, surgical technique, and how “success” is defined.
All types of BMG urethroplasty have a similar success rate of 83–91% in the intermediate follow-up, and the two-stage approach appears to be better, even if there is a lack of strong evidence.
For the most complex cases — those involving multiple prior failed repairs — results are somewhat less favorable. In one published series of 16 urethral reconstructions using buccal mucosal grafts in complex hypospadias (12 of whom had previously failed urethroplasties), 11 of 16 patients (69%) developed complications after 14 to 27 months of follow-up, including meatal stenosis in 2 (12.5%), urethral stricture in 5 (31%), and urethrocutaneous fistula in 4 (25%). No oral complications were seen, and all of the urethroplasty complications were managed successfully.
This high complication rate reflects the extraordinary difficulty of the patient population — not the technique’s failure. The same study’s conclusion is telling: the procedure remains an acceptable and justified treatment option precisely because the alternatives are so limited.
Key Outcomes Comparison by Technique
| Technique | Typical Success Rate | Main Complications | Best Suited For |
| Onlay BMG (single stage) | 80–91% | Fistula, stricture | Intact urethral plate present |
| Tubularized BMG (single stage) | 70–80% | Stricture, fistula, necrosis | No usable urethral plate |
| Two-stage BMG (Bracka technique) | 83–91% | Graft shrinkage, contracture | Extensive scarring; multiple prior failures |
| Lingual mucosal graft | ~76–78% | Slurred speech, tongue restriction | Limited buccal tissue available |
Success rates reflect published intermediate-term follow-up data across multiple series.
In a comparative study of buccal versus lingual mucosal grafts for complex hypospadias, successful urethroplasty was obtained in 78.2% of the buccal mucosal graft group compared to 76.1% of the lingual mucosal graft group — outcomes that were comparable between the two approaches.
Complications: What Patients and Families Should Know
Urethral Complications
The most common adverse outcomes following BMG urethroplasty for complex hypospadias are:
- Urethrocutaneous fistula — an abnormal tract between the reconstructed urethra and the skin surface, typically requiring surgical closure
- Urethral stricture — narrowing of the reconstructed urethra, causing obstructive voiding symptoms; may require dilation or further surgery
- Meatal stenosis — narrowing of the urethral opening at the glans; often amenable to minor outpatient procedures
- Graft necrosis — loss of the graft due to inadequate vascularization; more common with tubularized techniques and poor graft bed preparation
- Recurrent chordee — persistent or recurrent penile curvature following repair
In one large series of 62 children with complex hypospadias including 26 “hypospadias cripples,” the overall complication rate was 13%, involving 4 fistulas, 3 cases of graft necrosis, and only 1 meatal stenosis during the follow-up period. This relatively favorable rate was attributed to meticulous onlay technique with complete graft thinning and avoidance of tubularized repairs where possible.
Oral Donor Site Complications
One of buccal mucosal grafting’s key advantages is its low harvest-site morbidity. Donor site pain was reported with both buccal and lingual graft techniques, but recovery was earlier with lingual grafts. Mouth tightness, peri-oral numbness, and persistent oral discomfort were reported with buccal grafts but not with lingual grafts.
Serious or permanent oral complications are uncommon. When compared with other substitution grafts for urethroplasty, buccal mucosal grafts have fewer donor site complications than lingual and lower lip grafts.
The Evidence Landscape: Strengths and Limitations
What the Research Tells Us — and What It Doesn’t
Numerous publications have explored oral mucosa urethroplasty outcomes, mainly through single-center retrospective analyses, often with small sample sizes and lacking long-term follow-up. Literature reviews and meta-analyses are scarce.
In a systematic review by Sharma et al. including 1,406 patients from 16 studies, oral mucosa was favored over penile skin grafts. A review by Markiewicz et al. covering hypospadias, epispadias, and strictures found onlay techniques superior to tube procedures, with multistaged repairs showing superiority in hypospadias cases but not in strictures.
The field still lacks large prospective randomized controlled trials — the challenge of performing such trials in pediatric reconstructive surgery is substantial. The absence of prospective randomized studies makes drawing definitive conclusions challenging, and long-term data are imperative, as emerging evidence suggests a potential decline in success rates over time.
Current Guidelines
Both major urological societies have weighed in on graft choice. Both the American Urological Association (AUA) and the European Urological Association (EUA) guidelines promote the preferential use of buccal mucosal grafts for urethral reconstruction over penile skin flaps.
Buccal mucosa remains the gold standard for substitution graft urethroplasty.
Looking Ahead: What’s on the Horizon?
Tissue engineering represents the most promising frontier for patients with severe, recurrent disease or insufficient oral tissue available for harvest. Tissue-engineered oral mucosa has been described with the intent to limit morbidity in patients with long-length urethral strictures or those with recurrences and limited oral mucosa available, such as patients with lichen sclerosis. This process involves autologously harvesting oral cells, which are then cultured on epithelial cell sheets; after two weeks, the sheets are tubularized to form a two-layered graft. Early clinical results have been mixed, and the approach remains experimental — but the trajectory is encouraging.
Conclusion: A Difficult Problem, a Reliable Tool
Buccal mucosal graft urethroplasty for complex hypospadias represents the current best available answer to one of pediatric and reconstructive urology’s hardest problems. The technique is well-established, supported by decades of evidence, endorsed by major urological guidelines, and — in skilled hands — delivers durable functional outcomes even in patients who have already experienced multiple surgical failures.
The key takeaways for patients and families navigating this journey:
- Complex hypospadias — particularly cases involving prior failed repairs — carries meaningful surgical risk regardless of technique. Realistic outcome expectations are essential before proceeding.
- The onlay technique generally outperforms tubularized reconstruction; when the urethral plate can be preserved, it should be.
- Two-stage repair is the preferred approach for the most severely scarred or tissue-deficient cases, despite the burden of an additional procedure.
- Oral donor site complications are typically minor and self-limiting; permanent harm to oral function is rare.
- Long-term follow-up is essential — urethral strictures and fistulae can develop months to years after surgery, and recurrence requires prompt urological attention.
- Surgery should be performed at a high-volume center with dedicated expertise in reconstructive urology — outcomes are strongly correlated with surgical experience in this technically demanding field.
If your child or a family member is facing complex hypospadias repair, ask specifically whether a specialist in pediatric reconstructive urology or a center with a dedicated hypospadias program has been involved in the planning. The right expertise makes a measurable difference.