Anterior Obturator Artery Perforator (aOAP) Flap — Vulvovestibular Reconstruction
The aOAP flap is a fasciocutaneous perforator flap developed by Dan mon O'Dey (Aachen / Luisenhospital, Germany) for vulvovestibular reconstruction. Originally described in 2010 based on cadaveric vascular anatomy, it has been applied to two major clinical indications: female genital mutilation/cutting (FGM/C) reconstruction and refractory lichen sclerosus et atrophicus (LSA) with sexual dysfunction as a last-resort surgical option.[1][2][3]
For the broader treatment menu see the Vulvar Reconstruction Atlas. The aOAP shares its vascular territory with the genitocrural island perforator flap (GCIPF) used for oncologic reconstruction — see GCIPF (Vulvar). For the FGM/C complement technique see Foldès Clitoral Reconstruction; for the alternative coverage technique see Mañero Vaginal Mucosal Graft.
Vascular Anatomy
O'Dey, Bozkurt & Pallua 2010 — 20 specimens from 10 female cadavers:[1]
| Parameter | Detail |
|---|---|
| Source vessel | Anterior branch of the obturator artery (and accompanying vein), exits the pelvis through the obturator foramen |
| Perforator type | 80% musculocutaneous (pierces the gracilis muscle); 20% septocutaneous (passes along the posterior border of the gracilis) |
| Perforator location | 1.3 ± 0.3 cm lateral to the inferior pubic ramus |
| Skin territory | ~7 × 15 cm, centered on the sulcus genitofemoralis (genitocrural fold) |
| Tissue characteristics | Thin, pliable, hairless — closely matches native vulvar / vestibular tissue in texture, color, and thickness[1] |
Consistent with the four constant perineal perforator arteries identified by Jin et al., with rich vascular anastomoses in the deep fascia above the adductor compartment.[4]
Key Advantages
| Advantage | Detail |
|---|---|
| Thin and pliable tissue | Closely mimics native vulvar / vestibular skin — avoids the excessive bulk of musculocutaneous flaps (gracilis, VRAM) that can impair sexual function and cosmesis[1][2] |
| Proximity to defect | Donor site (genitocrural sulcus) is immediately adjacent to the vulva — minimal arc of rotation; tunneled-island design[1] |
| Concealed donor site | Scar hidden within the natural genitocrural fold; preserves self-image[1] |
| Primary donor closure | Donor site closed primarily in most cases[1] |
| Constant vascular anatomy | aOAP perforator present in 100% of cadaveric specimens; predictable location relative to the inferior pubic ramus[1] |
Surgical Technique
- Preoperative planning — handheld Doppler identifies the perforator ~1.3 cm lateral to the inferior pubic ramus along the genitocrural sulcus. Flap designed as an elliptical island centered on the perforator, oriented along the sulcus genitofemoralis.[1]
- Flap dimensions — skin paddle up to ~7 × 15 cm, tailored to the defect; bilateral flaps are typical for vulvovestibular reconstruction.[1][3]
- Flap elevation — raised as a fasciocutaneous island. Dissection from periphery toward the perforator. If musculocutaneous (80%), a small cuff of gracilis muscle is included around the pedicle to protect it; if septocutaneous (20%), perforator dissected along the intermuscular septum.[1]
- Tunneled transfer — flap transferred to the vulvar / vestibular defect through a subcutaneous tunnel, preserving the pedicle without skeletonization. This tunneled-island design distinguishes the aOAP from simple transposition flaps.[1]
- Inset and closure — flap inset with fine absorbable sutures; donor site closed primarily.[1]
Clinical Application 1 — FGM/C Reconstruction (O'Dey 2024, n = 119)[2]
In O'Dey's 2014–2021 FGM/C cohort, the aOAP flap was used in 36% of patients (~ 43 women) for vulvovestibular reconstruction — specifically the labia minora, vestibule, and / or vaginal introitus in women with extensive tissue loss from FGM/C (particularly Types II and III).
Three-technique reconstructive system
| Technique | Purpose | Frequency |
|---|---|---|
| Omega Domed (OD) Flap | Preputial (clitoral hood) reconstruction | 85% |
| NMCS Procedure (Neurotizing and Molding of Clitoral Stump) | Clitoral reconstruction | 82% |
| aOAP Flap | Vulvovestibular reconstruction (labia minora, vestibule) | 36% |
Outcomes (combined techniques, n = 119)[2]
- Significant postoperative improvement in clitoral sensation and ability to achieve orgasm (p < 0.05).
- Significant reduction in dysmenorrhea, dysuria, and dyspareunia (p < 0.05).
Clinical Application 2 — Refractory Lichen Sclerosus et Atrophicus (LSA)
O'Dey 2024 — last-resort surgical option for refractory LSA with sexual dysfunction.[3]
Indication: women with LSA refractory to conservative therapy (topical corticosteroids) who had disabling dyspareunia or apareunia preventing sexual intercourse.
Procedure: skinning vulvectomy (excision of affected vulvovestibular tissue) followed by single-stage bilateral aOAP flap reconstruction in 53/61 (87%) cases. Additional procedures included the OD flap, scar surgery, and clitoral re-exposure when indicated.
Outcomes[3]
- Significant reduction in dyspareunia at 1-y follow-up (p < 0.05).
- Significant improvement in vulvar pain and sexual function.
- Some patients required adjunctive procedures.
LSA-specific caveat
Prior surgical LSA studies using simpler techniques (perineoplasty, local skin flaps) have shown that while short-term functional results are acceptable, the chronic relapsing nature of LSA often leads to varying and sometimes short-term coital improvements — Rangatchew et al. reported 38% severe relapse requiring re-intervention with simpler approaches.[5][6]
Comparison with Other Vulvar Reconstruction Flaps
| Flap | Type | Tissue quality | Bulk | Donor scar | Muscle sacrifice | Key advantage | Key limitation |
|---|---|---|---|---|---|---|---|
| aOAP | Fasciocutaneous perforator | Thin, pliable, hairless | Minimal | Concealed (genitocrural fold) | None (or minimal gracilis cuff) | Best tissue match for vulva; concealed scar | Single-surgeon experience; limited published data |
| Lotus petal / pudendal-thigh | Fasciocutaneous axial | Thin, pliable | Low-moderate | Perineal / gluteal fold | None | Retains sensory innervation; versatile | Limited skin territory for large defects |
| PAP / DFAP | Fasciocutaneous perforator | Moderate thickness | Low-moderate | Posterior medial thigh | None | Large skin paddle; reliable anatomy | Higher wound complication rate (37.5%) vs IPAP (12.9%) |
| Gracilis | Musculocutaneous | Moderate-thick | Moderate-high | Medial thigh | Gracilis muscle | Reliable; fills dead space | Excessive bulk; functional muscle loss |
| VRAM | Musculocutaneous | Thick | High | Abdominal wall | Rectus abdominis | Large volume; fills pelvic dead space | Highest donor-site morbidity (57.6%); abdominal-wall weakness |
The Wendelspiess 2024 SR / meta-analysis of perforator vs non-perforator flaps for vulvoperineal reconstruction (49 studies, n = 1,840) found a tendency toward fewer complications with perforator flaps — though the difference did not reach statistical significance; long-term outcomes and QOL assessment were sparse.[7]
Limitations and Considerations
| Limitation | Detail |
|---|---|
| Single-surgeon experience | All published aOAP data originate from O'Dey's center (Luisenhospital Aachen, Germany); no independent or multicenter replication[1][2][3] |
| No comparative trials | No head-to-head comparisons with other perforator flaps (IPAP, PAP) or with the lotus-petal flap |
| Perforator variability | aOAP present in 100% of cadaveric specimens, but 20% are septocutaneous rather than musculocutaneous — affects elevation technique[1] |
| Learning curve | Perforator-flap dissection requires microsurgical expertise and familiarity with obturator vascular anatomy |
| LSA recurrence | Chronic relapsing nature of LSA means long-term durability of reconstruction is uncertain[5] |
| Combined technique | In FGM/C, aOAP was always used in combination with OD and / or NMCS — difficult to isolate the specific contribution of the aOAP to overall outcomes[2] |
Key Takeaways
- The aOAP flap is a fasciocutaneous perforator flap (anterior branch of the obturator artery) developed by O'Dey for vulvovestibular reconstruction.[1]
- Two major clinical indications — FGM/C (vulvovestibular reconstruction in 36% of O'Dey's n = 119 cohort) and refractory LSA (87% of n = 61 received bilateral aOAP after skinning vulvectomy).[2][3]
- Vascular anatomy — perforator present in 100% of cadaveric specimens, located 1.3 ± 0.3 cm lateral to the inferior pubic ramus, supplying a ~7 × 15 cm skin territory centered on the sulcus genitofemoralis.[1]
- Key advantages — tissue match (thin, pliable, hairless), concealed donor scar, tunneled-island design, primary donor closure.[1]
- Evidence base limited to a single surgeon's experience — no independent multicenter or comparative validation.[1][2][3]
- The aOAP vascular territory overlaps with the GCIPF used for oncologic vulvar reconstruction (Toulouse algorithm) — same flap, different clinical contexts.
References
1. O'Dey DM, Bozkurt A, Pallua N. The anterior obturator artery perforator (aOAP) flap: surgical anatomy and application of a method for vulvar reconstruction. Gynecol Oncol. 2010;119(3):526–530. doi:10.1016/j.ygyno.2010.08.033
2. O'Dey DM, Kameh Khosh M, Boersch N. Anatomical reconstruction following female genital mutilation/cutting. Plast Reconstr Surg. 2024;154(2):426–438. doi:10.1097/PRS.0000000000011026
3. O'Dey DM, Rosendahl M, Mordehay D, Kameh Khosh M. Anterior obturator artery perforator (aOAP) flap: a last-resort treatment option for sexual dysfunction in lichen sclerosus et atrophicus. J Plast Reconstr Aesthet Surg. 2024;95:331–339. doi:10.1016/j.bjps.2024.05.046
4. Jin B, Hasi W, Yang C, Song J. A microdissection study of perforating vessels in the perineum: implication in designing perforator flaps. Ann Plast Surg. 2009;63(6):665–669. doi:10.1097/SAP.0b013e3181999de3
5. Rangatchew F, Knudsen J, Thomsen MV, Drzewiecki KT. Surgical treatment of disabling conditions caused by anogenital lichen sclerosus in women: an account of surgical procedures and results, including patient satisfaction, benefits, and improvements in health-related quality of life. J Plast Reconstr Aesthet Surg. 2017;70(4):501–508. doi:10.1016/j.bjps.2016.12.008
6. Lauber F, Vaz I, Krebs J, Günthert AR. Outcome of perineoplasty and de-adhesion in patients with vulvar lichen sclerosus and sexual disorders. Eur J Obstet Gynecol Reprod Biol. 2021;258:38–42. doi:10.1016/j.ejogrb.2020.12.030
7. Wendelspiess S, Kouba L, Stoffel J, et al. Perforator versus non-perforator flap-based vulvoperineal reconstruction — a systematic review and meta-analysis. Cancers. 2024;16(12):2213. doi:10.3390/cancers16122213