Grafts in Genitourinary Reconstruction
A graft is tissue transferred from a donor site to a recipient site without its native blood supply. Grafts are selected when the recipient bed is well-vascularized, when flap reconstruction is unnecessary or disproportionate to the defect, or when the surgeon requires specific tissue properties — particularly mucosal lining — that only certain donor sites provide.
This page serves as a reference database for grafts used in genitourinary reconstruction.
Graft Take: Imbibition and Inosculation
Understanding graft physiology is critical for the reconstructive urologist. Graft survival depends entirely on re-establishment of perfusion from the recipient bed by two sequential processes:[2][1]
Imbibition (0–48 hours)
Passive diffusion of nutrients and metabolic byproducts between the graft and the recipient wound bed. The graft absorbs plasma exudate from the recipient site, maintaining graft cell viability until a vascular supply is re-established. During this phase, grafts appear edematous and pale; any fluid accumulation between graft and bed directly inhibits this passive exchange.
Inosculation (48 hours – 1 week)
Active formation of new vascular connections: host capillaries grow into the graft substance (neovascularization), and residual graft vessels align with and connect to host vessels (direct capillary anastomosis). By day 5–7, blood flow through the graft is re-established and the graft appears pink and viable.
Factors Affecting Graft Take
| Factor | Effect |
|---|---|
| Recipient bed vascularity | Primary determinant of take; avascular, irradiated, or ischemic beds have markedly impaired take |
| Graft-bed apposition | Dead space (hematoma, seroma, urinoma) between graft and bed physically prevents imbibition and inosculation — the most common cause of graft failure. The quilting stitch — multiple small interrupted bites securing the graft to the bed across its surface — is the canonical technique for ensuring intimate apposition and obliterating dead space, particularly for BMG quilted to corpus spongiosum or tunica albuginea, and for STSG fixation to perineal / scrotal beds. |
| Immobilization | Movement shears developing capillary connections; 48–72 hours of immobilization is standard practice. Quilting stitches and bolster dressings both serve this function. |
| Infection | Bacterial colonization impairs inosculation and lowers tissue oxygen tension |
| Graft thickness | Thinner grafts (STSG, thin buccal mucosa) take more readily due to shorter diffusion distance during imbibition |
| Graft defatting | Removing excess submucosal/subcutaneous fat reduces diffusion distance and improves contact with the recipient bed |
Omentum as Vascularized Graft Backing. In buccal mucosal graft (BMG) ureteroplasty, an omental flap serves a dual critical role: it provides a vascularized backing that drives graft neovascularization, and its porous structure permits drainage of any fluid accumulation from beneath the graft — directly preventing the dead space that impairs inosculation. Without vascularized backing, BMG ureteroplasty has inferior outcomes.[1]
Quick Reference: Grafts in GU Reconstruction
| Graft | Type | Harvest Site | Epithelium | Primary GU Applications |
|---|---|---|---|---|
| Buccal mucosa | Mucosal | Inner cheek | Non-keratinizing stratified squamous | Anterior/posterior urethroplasty, ureteral reconstruction (BMG ureteroplasty) |
| Lingual mucosa | Mucosal | Ventral/lateral tongue | Non-keratinizing stratified squamous | Urethroplasty (when buccal unavailable) |
| Labial mucosa | Mucosal | Inner lip | Non-keratinizing stratified squamous | Female urethroplasty; secondary site when buccal exhausted |
| Rectal mucosa | Mucosal | Distal rectum (transanal) | Simple columnar | Salvage / second-line urethroplasty when oral mucosa is exhausted, contraindicated, or insufficient for very long strictures |
| Intestinal segment | Epithelial / visceral | Ileum, sigmoid, cecum | Columnar (secretory) | Bladder augmentation, neobladder, conduit, vaginal reconstruction |
| Penile / preputial skin | Skin | Penile shaft, prepuce | Thin keratinizing (non-hair-bearing) | Hypospadias repair, anterior urethroplasty |
| Saphenous vein | Vascular | Medial thigh/leg | Endothelium | Penile vascular reconstruction (ED surgery) |
| Posterior auricular skin | Skin (FTSG) | Retroauricular sulcus | Thin keratinizing | Urethroplasty, penile skin (pediatric); fine cosmetic results |
| Split-thickness skin (STSG) | Skin | Thigh, buttock, scalp | Thin keratinizing | Scrotal/perineal resurfacing, penile shaft, vaginal reconstruction (McIndoe) |
| Full-thickness skin (FTSG) | Skin | Groin, prepuce, postauricular | Keratinizing ± dermis | Penile shaft, hypospadias, genital reconstruction (minimal contraction) |
| Bladder mucosa | Mucosal | Bladder wall | Transitional (urothelium) | Hypospadias (historical); largely replaced by buccal mucosa |
Graft Detail
Buccal Mucosa Graft (BMG)
→ Dedicated page: Buccal Mucosa Graft
The most widely used graft in urethral reconstruction and the emerging standard for ureteral augmentation. Harvested from the inner cheek (buccal mucosa), with bilateral harvest possible when a longer graft is needed.
Histologic properties:
- Thick, non-keratinizing stratified squamous epithelium
- Thin, highly vascular lamina propria — facilitates rapid inosculation with the recipient bed
- Resistant to the wet environment of the urinary tract
- Lacks hair follicles — safe for urethral lumen use
- Properties approximate urothelium more closely than any other easily accessible mucosal donor site
GU applications:
- Anterior urethroplasty: Onlay BMG (dorsal, ventral, or lateral) for bulbar strictures; augmented anastomotic urethroplasty for complex strictures
- Posterior urethroplasty: Onlay graft for membranous/posterior urethral reconstruction in combination with anastomotic repair
- Female urethroplasty: Onlay augmentation for female urethral stricture
- BMG ureteroplasty: Onlay patch augmentation for long ureteral strictures not amenable to primary repair; requires omental backing for vascularized support and fluid drainage
Harvest technique:
- Cheek retracted with a self-retaining retractor; commissure of the mouth must be avoided
- Parotid duct (Stensen's duct) identified at the level of the upper second molar and avoided
- Graft harvested with scissors; donor site may be left open or closed — both approaches are safe
- Bilateral cheek harvest allows graft lengths up to 12–14 cm
Limitations: Maximum combined bilateral cheek harvest typically 6–7 cm per side; donor site complications include transient numbness, trismus, scarring; not available if prior buccal surgery, radiation, or significant fibrosis; tobacco use impairs tissue quality
Lingual Mucosa Graft
→ Dedicated page: Lingual Mucosa Graft
Harvested from the ventral or lateral surface of the tongue. Histologically similar to buccal mucosa and used as a secondary or supplementary donor site.
Histologic properties:
- Non-keratinizing stratified squamous epithelium
- Slightly thinner lamina propria than buccal mucosa (some surgeons prefer this for urethroplasty)
- Comparable vascularity and recipient bed integration
GU applications:
- Urethroplasty: Used when buccal donor sites are unavailable or exhausted (prior buccal harvest, oral fibrosis, submucous fibrosis)
- Can be combined with buccal graft to extend total graft length in long-segment strictures
Limitations: Higher risk of donor site hematoma (greater vascularity of tongue); tip of tongue and lingual nerve must be protected; patient may notice altered taste or tongue mobility; harvest from ventral surface preferred (avoids dorsal papillae and lingual nerve)
Labial Mucosa Graft
→ Dedicated page: Labial Mucosa Graft
Harvested from the inner surface of the upper or lower lip (vermilion mucosa). Thinner and less robust than buccal mucosa, with a more limited harvest territory.
GU applications:
- Female urethral reconstruction: Onlay graft for female urethral stricture — labial mucosa is anatomically accessible and appropriate in women
- Used when other mucosal sites are unavailable
- Occasionally used in pediatric urethroplasty
Limitations: Small donor territory limits graft length (typically <3 cm per lip); thinner submucosal layer than buccal; more conspicuous donor site deformity; not a primary first-line option in adults when buccal is available
Rectal Mucosa Graft
Rectal mucosa grafts (RMGs) are an emerging second-line graft material for substitution urethroplasty when oral mucosa is unavailable, insufficient, or contraindicated — particularly in long-segment and panurethral strictures.[3][4] Colonic mucosal grafts for urethral reconstruction date back to Thyrmos in 1902,[5] but adoption was historically limited because retrieval required sigmoid resection. The development of minimally invasive transanal harvest beginning in 2013 has revitalized the option.[4]
For the full named-operation framing — including the broader Mundy/Andrich intestinal interposition and Xu colonic-mucosa-graft techniques RMGs evolved from — see Enterourethroplasty.
Indications. Used when BMG is not feasible:
- Prior failed BMG urethroplasty — 69% of patients in the largest multi-institutional series.[3]
- Long-segment strictures exceeding what oral mucosa can provide (median stricture length 13 cm in published series; mean graft 10.6 cm, range 3–21 cm).[3][6]
- Lichen sclerosus — the most common etiology in the multi-institutional series (46%), often with depleted oral mucosa from prior surgeries.[3]
- Strictures after gender-affirming phalloplasty, where neourethral strictures may be very long and oral mucosa is often already exhausted.[3][7]
- Oral pathology limiting buccal harvest — submucous fibrosis, prior head/neck radiation.[4]
The AUA 2023 urethral stricture guideline amendment continues to recommend oral mucosa as the first-choice graft (Expert Opinion); RMGs are not specifically addressed and serve as a recognized salvage option.[8]
Harvest techniques. Three minimally invasive transanal approaches, all under general anesthesia in lithotomy:
| Approach | First Description | Notes |
|---|---|---|
| Transanal Endoscopic Microsurgery (TEM) | Palmer / Vanni 2013[4] | Original technique; TEM platform for submucosal dissection |
| Robotic Transanal Minimally Invasive Surgery (R-TAMIS) | Howard / Zhao 2019[7] | GelPOINT Path platform with standard robot; mean graft 11.4 × 3.0 cm |
| Single-port endorobotic | Emrich Accioly / Ozgur 2022–2023[6][9] | Da Vinci SP + GelPOINT; pneumorectum 12 mmHg; grafts up to 21 × 3 cm |
Common technical steps: submucosal injection / hydrodissection (lifting agent such as ORISE gel) to elevate the mucosa, dissection beginning ~2 cm proximal to the sphincter complex and proceeding cranially, mucosa-only harvest, hemostasis confirmation (often with flexible sigmoidoscopy), and graft thinning before placement.[6][9]
Configurations. Used as dorsal onlay, ventral onlay, or as the first stage of a staged repair — Pagura demonstrated successful graft take at 6 months in staged urethroplasty.[5]
Outcomes. Total published experience is modest (~20–25 patients across all series) with short-to-intermediate follow-up:
| Series | N | Stricture-Free Rate | Follow-Up | Donor-Site Complications |
|---|---|---|---|---|
| Granieri 2019 (TURNS multi-institutional) | 13 | 85% (recurrence 15%) | 13.5 mo | None reported |
| Howard 2019 (R-TAMIS) | 7 | All graft take excellent; no recurrence | 17 mo | None reported |
| Palmer 2016 (TEM original series) | 4 | 75% (recurrence 25%) | 10 mo | None reported |
Other postoperative complications in the TURNS series (each 7%): glans dehiscence, urethrocutaneous fistula, compartment syndrome.[3] No rectal or bowel-related complications have been reported across all published series.[3][4][6][7][9]
Advantages over BMG.
- Larger graft dimensions — single grafts up to 21 cm, vs typical BMG 4–7 cm per cheek.[6][7]
- No oral morbidity — avoids pain, numbness, restricted mouth opening, salivary-duct injury.[7]
- Less postoperative pain — patients with prior BMG harvests subjectively reported less pain and greater quality of life with rectal harvest.[7]
- Rapid bowel recovery — bowel function typically returns POD 1; discharge POD 2.[6][7]
Limitations and caveats.
- Total published experience remains small (~20–25 patients) with short-to-intermediate follow-up.
- No head-to-head comparative studies vs BMG exist.
- Requires multidisciplinary collaboration with a colorectal surgeon experienced in transanal platforms; access to robotic transanal platforms may be limited.
- Long-term outcomes — graft contracture, functional voiding — remain unknown.
- Rectal mucosa is simple columnar epithelium, unlike the non-keratinizing stratified squamous epithelium of buccal/lingual/labial mucosa; long-term behavior of columnar epithelium in the urethral environment requires further study.
Intestinal Segments
→ Dedicated page: Intestinal Segments
Bowel segments used in urinary tract reconstruction leverage the intestinal mucosa's secretory properties, bulk availability, and native blood supply (transferred as vascularized pedicle, not a graft in the strictest sense — but included here as a tissue substitution resource).
| Segment | Key Properties | Primary Applications |
|---|---|---|
| Ileum | Most compliant; mucus production; longest pedicle | Bladder augmentation (ileocystoplasty), orthotopic neobladder (Studer, W-pouch), ileal conduit urinary diversion |
| Sigmoid colon | Thick wall; less compliant; larger caliber; adequate pedicle | Bladder augmentation, vaginal reconstruction (McIndoe sigmoid neovagina), colon conduit |
| Ileocecal segment | Anti-reflux ileocecal valve usable; cecum provides reservoir | Ileocecal augmentation (Mainz pouch), continent cutaneous diversion |
Metabolic complications of intestinal urinary reconstruction:
- Mucus production → catheter occlusion, urinary tract infection
- Electrolyte reabsorption (ileal/colonic urine contact) → hyperchloremic metabolic acidosis
- Vitamin B12 deficiency (terminal ileum)
- Increased risk of secondary malignancy in augmented bladder (long-term surveillance required)
Penile / Preputial Skin Graft
→ Dedicated page: Penile / Preputial Skin Graft
Non-glabrous preputial or penile shaft skin used as a free graft (without dartos pedicle) or as a pedicled flap. As a graft (no vascular pedicle), it is used primarily in pediatric hypospadias repair.
Key properties:
- Thin, non-keratinizing to mildly keratinizing epithelium when non-hair-bearing
- Elasticity and compliance similar to native penile skin
- Hair-bearing shaft skin is contraindicated for urethral lumen application (hair growth causes urethral calculi, obstruction, infection)
GU applications:
- Hypospadias repair — preputial free graft (Duckett inner preputial island flap as graft; Snodgrass TIP urethroplasty)
- Anterior urethroplasty in adolescents/adults with intact prepuce and short strictures
- Penile shaft resurfacing after degloving injuries (non-hair-bearing skin only)
Limitations: Only available in uncircumcised patients; must be non-hair-bearing; not recommended for long-segment substitution urethroplasty in adults (inferior outcomes vs. BMG)
Saphenous Vein Graft
→ Dedicated page: Saphenous Vein Graft
An autologous vascular conduit used in penile vascular surgery and, historically, in ureteral reconstruction.
GU applications:
- Penile revascularization surgery (arteriogenic erectile dysfunction): anastomosis of the deep inferior epigastric artery to the dorsal penile artery, with saphenous vein as interposition conduit
- Penile venous surgery (venogenic ED): venous ligation/excision procedures
- Historical ureteral use: Vein graft ureteroplasty has been described but is largely abandoned due to high stricture rates; replaced by BMG ureteroplasty
Limitations: Venous wall is thin and susceptible to stricture in the urinary tract environment; not a first-line urological graft; donor site morbidity (leg wound)
Posterior Auricular Skin Graft
→ Dedicated page: Posterior Auricular Skin Graft
A full-thickness skin graft (FTSG) harvested from the retroauricular (postauricular) sulcus — the skin between the pinna and mastoid. This region provides uniquely thin, non-hair-bearing, supple skin with favorable cosmetic properties.
Key properties:
- Very thin dermis — takes readily as an FTSG
- Non-hair-bearing
- Minimal pigmentation mismatch for fair-skinned patients
- Harvest site hidden behind the ear; donor scar not visible
GU applications:
- Urethroplasty: Used at some centers as an alternative to buccal mucosa for short-segment urethral reconstruction, particularly in pediatric patients
- Penile skin reconstruction: Where thin FTSG is preferred and preputial skin is unavailable
- Hypospadias: Postauricular FTSGs have been used in redo/salvage hypospadias surgery
Limitations: Limited harvest size (typically 3–5 cm); thin dermis requires careful handling; not as well-studied as buccal mucosa in urethral applications; two-field surgery
Skin Grafts (STSG and FTSG)
→ Dedicated pages: Split-Thickness Skin Graft (STSG) · Full-Thickness Skin Graft (FTSG)
Standard dermal grafts used for coverage of large cutaneous or subcutaneous deficits in the genital/perineal region.
| Type | Composition | Take Rate | Contraction | Common GU Applications |
|---|---|---|---|---|
| STSG | Epidermis + partial dermis | High (if bed vascularized) | Significant (primary and secondary) | Scrotal resurfacing (post-Fournier's), penile shaft, perineal wound coverage, vaginal reconstruction lining |
| FTSG | Epidermis + full dermis | Lower (more metabolically demanding) | Minimal | Penile shaft (degloving, oncologic resection), hypospadias (genital skin where contraction must be avoided), pediatric genital reconstruction |
Requirements for take: Well-vascularized, clean recipient bed; no hematoma or seroma; immobilization for 48–72 hours post-grafting.
Scrotal STSG (Fournier's reconstruction): The scrotal skin has exceptional regenerative capacity, and STSG coverage of post-Fournier's scrotal defects produces good long-term outcomes with minimal contracture given the mobile, redundant scrotal architecture. Meshed STSG (1:1.5 or 1:2 expansion) is preferred for conforming to irregular perineal anatomy.
McIndoe STSG neovagina: Split-thickness skin grafted over a vaginal mold for creation of a neovagina in vaginal agenesis (Mayer-Rokitansky-Küster-Hauser syndrome); requires prolonged postoperative dilation.
Bladder Mucosa Graft
→ Dedicated page: Bladder Mucosa Graft
Transitional (urothelial) epithelium harvested from the bladder wall, used historically as a urethral graft.
Key properties:
- Native urothelium — theoretically the ideal urethral lining substitute
- Fragile, thin mucosa; technically demanding harvest
- Requires open or cystoscopic access to the bladder for harvest
GU applications:
- Historical use in hypospadias repair and anterior urethroplasty — used prior to the widespread adoption of buccal mucosa
- Bladder mucosal graft urethroplasty (Memmelaar technique, 1947; later Hendren and others)
Current status: Largely abandoned in favor of buccal mucosa. Buccal mucosa has superior handling characteristics, lower donor site morbidity, equivalent or superior success rates, and does not require cystotomy for harvest. Bladder mucosal grafts are now of primarily historical interest.
Tissue-Engineered Grafts & Bioscaffolds
Acellular matrices, decellularized small-intestinal submucosa (SIS), and cell-seeded scaffold constructs developed to replace autologous donor-site harvest. See the dedicated deep dive: Tissue-Engineered Grafts & Bioscaffolds — current evidence in urethroplasty, bladder, and vaginal reconstruction; FDA / regulatory status; failure modes; why autologous BMG remains the urethroplasty standard.
Graft Selection Summary
| Clinical Scenario | Preferred Graft | Rationale |
|---|---|---|
| Anterior urethral stricture (bulbar) | Buccal mucosa | Best-studied, optimal histology, abundant supply |
| Long-segment urethral stricture (>6 cm) | Bilateral BMG or BMG + lingual | Combined harvest extends length |
| Buccal sites exhausted or unavailable | Lingual mucosa | Similar histology; accessible secondary site |
| Panurethral / very long stricture, oral mucosa exhausted or contraindicated | Rectal mucosa (transanal harvest) | Single grafts up to 21 cm; salvage option, especially after failed BMG and in post-phalloplasty neourethral strictures |
| Female urethral stricture | BMG or labial mucosa | Both appropriate; BMG preferred if adequate oral health |
| Long ureteral stricture | BMG (with omental backing) | Only mucosal graft with adequate long-term ureteral data |
| Post-Fournier's scrotal resurfacing | Meshed STSG | High take rate; accommodates irregular contour |
| Penile shaft degloving | FTSG (preputial or groin) | Minimal contraction essential on penile shaft |
| Bladder augmentation | Ileum | Compliance, bulk, acceptable long-term metabolic profile |
| Hypospadias (primary, pediatric) | Preputial skin or BMG | Preputial skin in uncircumcised; BMG for tubularized neourethra |
References
1. Zhao LC, Yamaguchi Y, Bryk DJ, Adelstein SA, Fakhroo AA, Stifelman MD. Robot-assisted laparoscopic ureteral reconstruction with buccal mucosa graft. Urology. 2015;86(3):634–638. PMID 26199153
2. Converse JM, Uhlschmid GK, Ballantyne DL Jr. "Inosculation" of vessels of skin graft and host bed: a fortuitous encounter. Plast Reconstr Surg. 1969;43(6):605–616. PMID 5786095
3. Granieri MA, Zhao LC, Breyer BN, et al. Multi-institutional outcomes of minimally invasive harvest of rectal mucosa graft for anterior urethral reconstruction. J Urol. 2019;201(6):1164-1170. doi:10.1097/JU.0000000000000087.
4. Palmer DA, Marcello PW, Zinman LN, Vanni AJ. Urethral reconstruction with rectal mucosa graft onlay: a novel, minimally invasive technique. J Urol. 2016;196(3):782-786. doi:10.1016/j.juro.2016.03.002.
5. Pagura EJ, Cavallo JA, Zinman LN, Vanni AJ. Rectal mucosa graft take in staged urethroplasty. Urology. 2019;127:e1-e2. doi:10.1016/j.urology.2019.02.023.
6. Emrich Accioly JP, Zhao H, Ozgur I, et al. Single-port, robot-assisted transanal harvest of rectal mucosa grafts for substitution urethroplasty. Urology. 2022;166:1-5. doi:10.1016/j.urology.2022.04.018.
7. Howard KN, Zhao LC, Weinberg AC, et al. Robotic transanal minimally invasive rectal mucosa harvest. Surg Endosc. 2019;33(10):3478-3483. doi:10.1007/s00464-019-06893-w.
8. 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.
9. Ozgur I, Justiniano CF, Wood HM, Gorgun E. Single-port endorobotic rectal mucosa harvest for urethral reconstruction. Dis Colon Rectum. 2023;66(2):e54-e57. doi:10.1097/DCR.0000000000002577.