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The Leg & Thigh

In urologic reconstruction the lower extremity serves as a donor site and as a neuromodulation target. Two structures warrant a dedicated anatomic reference:

  • The gracilis muscle. The main muscle flap of pelvic reconstruction, used for rectourethral fistula interposition, perineal coverage after Fournier's or APR, urethral neosphincter construction, and long-segment urethroplasty in the radiated pelvis.
  • The tibial nerve at the medial ankle. The peripheral target of percutaneous and implantable tibial-nerve stimulation (PTNS / iTNS) for overactive bladder; treatment selection is individualized, and a third-line sequence is not mandatory.

See also The Perineum for the gracilis recipient bed; The Vulva for Martius flap alternatives; Multiple Sclerosis and Neurogenic Lower Urinary Tract Dysfunction for the clinical indications of tibial-nerve stimulation.

Thigh — Compartment Overview​

The thigh is organized into three fascial compartments by the femur, intermuscular septa, and the surrounding fascia lata:

CompartmentDominant musclesInnervationReconstructive relevance
AnteriorQuadriceps (rectus femoris + three vasti); sartorius; iliopsoas (at proximal end)Femoral nerve (L2–L4)Rectus-femoris and vastus-lateralis flaps; femoral-nerve at risk in deep retroperitoneal / retractor placement
Medial (adductor)Gracilis, adductor longus, adductor brevis, adductor magnus, obturator externus, pectineusObturator nerve (L2–L4) for most adductors; femoral nerve for pectineus (variable obturator contribution)[29]; sciatic branch to adductor magnusGracilis flap territory; obturator nerve at risk in TOT sling and obturator-LN dissection
Posterior (hamstring)Biceps femoris, semitendinosus, semimembranosusSciatic nerve (L4–S3)Hamstring autografts (orthopedic); sciatic-nerve injury with prone / lithotomy positioning

The adductor hiatus in the distal adductor magnus transmits the femoral artery and vein into the popliteal fossa, where they become the popliteal vessels. Above the hiatus, the femoral vessels course within the adductor (Hunter's) canal between adductor longus or magnus and vastus medialis.

The Gracilis Muscle​

The gracilis is a long, thin, strap-like muscle of the medial thigh that spans from the inferior pubic ramus to the pes anserinus on the medial proximal tibia. It is a weak hip adductor and knee flexor; other muscles compensate for much of its function after harvest. Donor-site effects are usually limited, but measurable adduction weakness and sensory changes can occur.[1][2][20]

Gross anatomy​

  • Length approximately 36–37 cm in one 44-limb cadaveric series; anatomy varies.[1]
  • Width tapered from approximately 25–27 mm at the origin to approximately 10–11 mm at the musculotendinous junction in that series.[1]
  • Tendon contributes approximately 6 cm of the musculotendinous length; inserts as part of the pes anserinus alongside sartorius and semitendinosus.
  • Lies superficial in the medial thigh, immediately beneath skin, subcutaneous fat, and fascia lata, which is why it can be harvested through a simple longitudinal medial-thigh incision with minimal muscle dissection.
  • Borders: adductor longus anteriorly, adductor magnus and sartorius posteriorly.

Vascular supply — a Mathes-Nahai Type II pattern​

The gracilis has one dominant pedicle plus one or more minor pedicles (Mathes-Nahai Type II). This is what gives the flap its large, reliable, rotatable proximal segment with a survivable distal extension:[3][4][5]

PedicleOriginLocationCaliberRole
Dominant (major)Profunda femoris artery (87%) or medial circumflex femoral (13%)Enters deep surface ~10 cm from the pubic tubercleMean 1.6 mm (profunda) or 1.2 mm (medial circumflex); 1.5–2.5 mm in another series; paired venae comitantesPrincipal supply for standard proximally based flaps; preservation depends on flap design[3][5][26]
Proximal (minor)Deep branch of medial circumflex femoral~6 cm from pubic tubercle~0.9 mmSupplies the proximal muscle
Distal (1–4 pedicles)Superficial femoral artery~26 cm from pubic tubercle1.4–2.0 mmSupport the distal third of the muscle

The distal pedicles form an anastomotic chain along the anterior border of the muscle, which is the basis of the distal-based or free gracilis flap.[3][4]

Venous drainage is via paired venae comitantes that accompany the arteries; discrete zones lack extensive intramuscular venous anastomoses, so harvest must respect the dominant pedicle's venous drainage.[4]

Neural supply​

The anterior division of the obturator nerve (L2–L4) enters the muscle with the dominant pedicle and splits into 2–3 longitudinal branches running parallel to the muscle fibers.[5] This consistent neurovascular bundle makes the gracilis suitable for functional (innervated) muscle transfer (for example, dynamic graciloplasty for fecal or urinary continence, facial reanimation).

The adductor-compartment anatomy near the gracilis pedicle (adductor longus anteriorly, adductor brevis deep) is what the extended pedicle dissection technique exploits to gain length.[11][12]

Internal architecture​

Contemporary microanatomic studies describe 4–7 longitudinal muscular compartments within the gracilis, each served by a branch of the obturator nerve and dominant arterial pedicle.[4] This compartmentalization is the theoretical basis for segmental (split) gracilis transfers in facial reanimation and specialized functional reconstructions, though for GU applications the muscle is typically harvested as a single unit.

Gracilis Flap — Techniques and Applications​

Harvest technique (overview)​

  • Positioning: supine, with the thigh abducted and externally rotated (frog-leg), knee flexed; often dorsal lithotomy combined with the recipient operation.
  • Incision: longitudinal medial-thigh skin incision along a line from the pubic tubercle to the medial tibial condyle; center the incision over the expected muscle (about 1 fingerbreadth posterior to the palpable adductor longus tendon).
  • Identification: open fascia lata, identify gracilis between adductor longus (anterior) and sartorius / adductor magnus (posterior), then confirm the distal tendon at the pes anserinus.
  • Pedicle protection: identify and preserve the dominant pedicle on the deep surface, approximately 8–10 cm from the pubic tubercle, where it courses between adductor longus and brevis; routine isolation is not required for every pelvic flap. In a described rectourethral-fistula interposition technique, segmental perforators are clipped and the dominant pedicle is rarely isolated to avoid injury.[5][30]
  • Distal release: divide the distal tendon at the pes anserinus; mobilize the muscle proximally toward its origin.
  • Tunnel: create a subcutaneous tunnel from the thigh wound to the perineum, passing the muscle on its pedicle.
  • Inset: position the muscle in the recipient bed (interposition, wrap, or coverage) and secure.

Extended pedicle dissection​

For reconstructions that demand greater pedicle length or arc of rotation (posterior perineum, deep pelvis, rectourethral fistula after prior reconstructive failure), the extended dissection carries the pedicle proximally beyond the adductor longus, divides adductor-longus perforators, and passes the gracilis under the adductor longus to access the profunda femoris directly.[11][12] Hasen described the technique for free gracilis flaps (18 patients, 100% flap survival).[11] Ducic applied it to pedicled flaps in 19 high-risk patients with complex perineal and groin wounds; all reconstructions were successful, with a greater arc of rotation and no restriction on postoperative ambulation or thigh abduction. Neither report gives a length gain in millimeters.

Reconstructive applications in GU​

IndicationRole of the gracilisReported outcomes
Rectourethral fistula (post-prostatectomy, post-radiation, post-cryo / HIFU)Interposition flap between urethral repair and rectal repair; brings non-irradiated vascularized tissue into the defectRetrospective series of 32 pelvic-fracture urethral defects with urethrorectal fistula: success 29/32 (91%) at mean 33 months, 7/10 (70%) after prior failed repair.[8]
Rectovaginal fistula (obstetric, IBD-related, post-radiation)Interposition between rectal and vaginal repairs; alternative to Martius when a bulkier flap is neededA 2023 pooled analysis of 20 mostly small series (384 patients) estimated fistula closure at 64% (95% CI 53%–74%); smoking, Crohn disease and more than two prior repairs were associated with failure.[31]
Perineal wound coverage after APR, pelvic exenteration, radical vulvectomy, Fournier's debridementFills dead space, brings vascularized tissue to irradiated or infected bedsWidely used, with VRAM, for large defects
Non-healing perineal / urogenital fistulae after radiationIntroduces non-irradiated tissue into the repairSelected indications; often the last available tissue option[10]
Long-segment urethroplasty with buccal-mucosa graft in high-risk / irradiated / reoperative fieldsCoverage flap over a buccal-graft urethroplasty to provide a vascularized bedRetrospective series of 30 patients (mean stricture 7.6 cm; 60% radiation-related): anatomic success (no recurrence by the study's 17-Fr cystoscope criterion) 23/30 (76.7%) at mean 32 months; 7 patients (23.3%) later needed an AUS; diversion avoided in most[9]
Urethral neosphincter (graciloplasty) for male acquired incontinenceMuscle wrapped around the bulbar urethra as an autologous compressive sphincter; dynamic (stimulated) or static configurationsIn 3 men after radical prostatectomy and external-beam radiation, mean Valsalva leak-point pressure rose from 26.3 to 83.0 cmH₂O (6–24 months).[6] In a 24-patient adynamic series (8 after radical prostatectomy, 7 after TURP, 9 after posterior urethroplasty), 18 (75%) were cured at mean 31.5 months, with poor results in severe incontinence.[7]
Vaginal reconstruction after exenteration / gender-affirming vaginoplasty complicationsGracilis myocutaneous flaps have been described for neovaginal reconstruction after pelvic exenteration[27]; gracilis interposition has been reported for recto-neovaginal fistula after gender-affirming vaginoplasty[28]—

Why the gracilis is preferred for pelvic reconstruction​

  • Long, thin, rotatable. Reaches from the medial thigh into the deep pelvis with minimal tension.
  • Defined proximal supply. The standard pelvic flap depends on its preserved dominant pedicle; distal accessory pedicles support the native distal muscle or selected alternative flap designs.[3][5][26]
  • Limited functional loss in many patients. Donor-site morbidity is real, including measurable hip-adduction weakness, sensory changes, and occasional contour or wound problems.[20]
  • Consistent neurovascular anatomy. Predictable dissection.
  • Non-irradiated donor tissue. Needed for repair in the post-radiation pelvis.
  • Modest donor-site scar in a concealable medial-thigh position.

Donor-site morbidity​

Generally limited. Reported findings:

  • Seroma. Reported early complication; typically managed with aspiration or drains.
  • Hematoma along the thigh wound.
  • Transient medial-thigh and medial-knee sensory paresthesia from small skin-nerve branches.
  • Wound infection / dehiscence. Low with primary closure and careful hemostasis.
  • Functional deficit. In a retrospective study of 42 patients, adduction strength fell by 11% on dynamometry without patient-noticed weakness, hypesthesia in the obturator cutaneous territory occurred in 40.5%, and thigh contour deformity occurred when a myocutaneous flap was raised.[20]

Medial-Ankle Anatomy for Tibial-Nerve Stimulation​

The posterior tibial nerve​

The posterior tibial nerve is a terminal branch of the sciatic nerve (L4–S3) that descends through the posterior compartment of the leg with the posterior tibial artery and vein. At the medial ankle, the nerve passes behind the medial malleolus within the tarsal tunnel (deep to the flexor retinaculum), where it divides into the medial and lateral plantar nerves that supply sensation and motor function to the sole of the foot.

For urologic neuromodulation purposes, the nerve is targeted just cephalad to the medial malleolus, posterior to the posterior border of the tibia. This site is sometimes called the "bladder center" for its clinical effect on lower-urinary-tract function.[13][15]

Regional neurovascular and tendinous anatomy at the target site​

A mapping study in 10 female cadavers (20 ankles) of the standard PTNS needle insertion site (about 3 fingerbreadths or 5 cm cephalad to the medial malleolus, posterior to the tibial border) reported the following nearby structures, distances, and relative locations. The 80% prediction intervals apply to the tibial nerve, posterior tibial vessels, and flexor digitorum longus tendon; the great saphenous vein and Achilles tendon values are approximate side-specific means.[14]

StructureDistance from the standard needle insertion site
Tibial nerve0–12.1 mm (the target)
Posterior tibial artery / vein0–9.5 mm
Flexor digitorum longus tendon0–13.9 mm
Flexor hallucis longus tendonVariable, posterior to the nerve
Tibialis posterior tendonAnterior to the needle target
Great saphenous vein~18–21 mm (asymmetric between legs)
Calcaneal (Achilles) tendon~8–13 mm (asymmetric)

Important surgical corollaries:

  • At the standard PTNS needle insertion site, the 80% prediction intervals from the insertion point were 0–12.1 mm to the tibial nerve and 0–9.5 mm to the posterior tibial artery or vein.[14] This is a procedural consideration for implantable devices and for needle placement.
  • The AUA guideline describes the PTNS protocol as a 34-gauge needle placed in the area of the posterior tibial nerve.[21]
  • The great saphenous vein and other nearby structures vary between individuals; the cadaveric study found a small left–right difference in mean vein distance.[14]

Mechanism of action — retrograde neuromodulation​

Tibial-nerve stimulation activates peripheral afferents that may influence sacral circuits (S2–S4) involved in bladder, urethral, and pelvic-floor control; the therapeutic mechanism remains incompletely defined.[13][15][16] Proposed mechanisms:

  • Modulation of detrusor overactivity while preserving the reflex micturition pathway.
  • Central effects on the pontine micturition center and periaqueductal grey via afferent input.
  • Peripheral effects on bladder afferent fibers (including capsaicin-sensitive C-fibers).
  • Neurotransmitter-level effects involving opioid and purinergic systems.

In 44 patients with overactive bladder (37 of them neurogenic), acute transcutaneous stimulation at 10 Hz increased the volume at first involuntary detrusor contraction (from about 163 to about 232 mL) and maximum cystometric capacity (from about 221 to about 277 mL); the test met the study's positive criterion in 22 of 44.[18]

Clinical applications​

Percutaneous tibial-nerve stimulation (PTNS) is a minimally invasive option for overactive bladder (OAB). The AUA/SUFU 2024 guideline states that clinicians should offer sacral neuromodulation, PTNS and/or intradetrusor botulinum toxin to patients with an inadequate response to, or intolerable side effects from, pharmacotherapy or behavioral therapy . Clinicians may also offer minimally invasive therapies without requiring prior behavioral or pharmacologic trials, in the context of shared decision-making .[21]

  • Common percutaneous protocol: a fine-gauge needle about 3 fingerbreadths cephalad to the medial malleolus and a surface return electrode on the foot. The AUA guideline describes the SUmiT protocol (34-gauge needle, 0.5–9 mA, 20 Hz, 30 minutes weekly for 12 weeks), and the Urgent PC/NURO device submission specifies 20 Hz, 200 µs pulse width and 30-minute sessions. Maintenance is individualized; use the specific device's current instructions.[21][22]
  • Evidence: At week 13 after 12 weekly sessions in the sham-controlled SUmiT randomized trial, 55% receiving PTNS versus 21% receiving sham reported moderate or marked improvement.[33] In women with OAB/UUI, the 2026 EAU guideline reports a greater reduction in UUI episodes with PTNS than with antimuscarinics but no difference in other OAB symptoms (level 1a), and strongly recommends offering PTNS.[32] The broader LUTD umbrella review judged the evidence low quality.[32][19]

Implantable tibial-nerve stimulation (iTNS) has been developed to address the limitations of percutaneous therapy (weekly office burden, limited insurance coverage, maintenance).[17]

  • Mechanism: the same retrograde tibial-to-sacral neuromodulation.
  • Implantation site and stimulation schedule: product-specific; systems differ in implant position, whether a lead is present, and patient versus automated control. Follow the selected device's current instructions; no single generic ankle-lead technique applies.
  • At-home stimulation can reduce repeated office visits, depending on the device and follow-up plan. In the single-arm Revi OASIS study, 151 women were implanted, 119 entered the extension, and 90 completed the 36-month assessment; 71/90 assessed had at least 50% fewer UUI episodes on a 3-day diary.[35]
  • Implantable tibial-nerve stimulators have received FDA marketing authorization; the AUA guideline notes that the literature on them is limited.[21] MRI conditions are device-specific: the eCoin-UUI physician manual permits 1.5-T or 3-T scanning only if the implant remains at least 20 cm from the edge of the scanner bore; its patient-controller magnet must not enter an MRI room or facility.[25]

Anatomic implications for the implanter:

  • Know the ankle variability; pre-op ultrasound mapping of the nerve and vessels is reasonable. For eCoin-UUI, the physician manual contraindicates implantation with open lower-leg or foot wounds, prior surgery or unhealed trauma at the implant site, pitting edema of 2+ or more, lower-leg venous or arterial insufficiency, vasculitis or dermatologic conditions of the lower leg, infection near the implant site, or inability to operate the patient-controller magnets and tape; follow the selected system's current labeling.[25]
  • The tibial vessels accompany the nerve; dissection and implant or lead placement must follow the selected system's instructions because implant designs differ.[24]
  • The flexor retinaculum marks the tarsal-tunnel region; implant location and tissue plane must follow the selected device's placement instructions.[25]

Relationship to sacral neuromodulation (SNM)​

PTNS and iTNS stimulate the tibial nerve at the ankle, with effects on sacral bladder-control pathways; SNM places a lead at a sacral root, usually S3.[16][34] In practical terms:

  • PTNS / iTNS. Peripheral, less invasive, office-based or small-implant; well-suited to OAB / UUI.
  • SNM. Lead at the S3 foramen; broader indications (OAB, non-obstructive retention, fecal incontinence, selected pelvic pain) but a more invasive, more expensive system with MRI-compatibility caveats.

See Neurogenic Lower Urinary Tract Dysfunction for when either is considered.

Clinical Correlations for the Reconstructive Urologist​

  • The gracilis is a muscle flap for pelvic reconstruction. Its harvest follows the medial-thigh plane between adductor longus and sartorius, with deliberate identification and preservation of the variable dominant pedicle before tunneling and tension-free inset.
  • Extended pedicle dissection increases the arc of rotation of a pedicled gracilis flap, which is useful for deep perineal and groin defects.
  • Gracilis versus Martius. Martius (labial fat pad) is thinner, has a shorter arc, and is ideal for urethrovaginal fistula, diverticulectomy, and VVF interposition. Gracilis is bulkier, reaches further, and is the choice when tissue volume or reach matters (rectourethral fistula, APR perineum, long-segment urethroplasty coverage). Both are non-irradiated flaps.
  • Gracilis neosphincter (graciloplasty) is an option for the highly selected patient with post-prostatectomy incontinence not amenable to AUS. It is uncommonly performed.
  • PTNS is a minimally invasive option for selected people with bothersome OAB after shared discussion of visit burden, maintenance and alternatives such as medication, SNM and botulinum toxin; no fixed first-/second-/third-line progression is required.[21]
  • iTNS delivers tibial-nerve stimulation through an implanted device. Implantation requires familiarity with the medial-ankle compartment.
  • The obturator nerve is the neural axis of the adductor compartment. It passes through the obturator canal and divides variably near the canal; its anterior division generally runs between adductor longus and brevis, while the posterior division courses deeper. Do not confuse this with the adductor (Hunter's) canal, which carries femoral vessels and the saphenous nerve. Obturator injury is a consideration during transobturator sling placement and obturator-node dissection.[23]

References​

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2. Macchi V, Vigato E, Porzionato A, et al. "The Gracilis Muscle and Its Use in Clinical Reconstruction: An Anatomical, Embryological, and Radiological Study." Clin Anat. 2008;21(7):696–704. doi:10.1002/ca.20685

3. Magden O, Tayfur V, Edizer M, Atabey A. "Anatomy of Gracilis Muscle Flap." J Craniofac Surg. 2010;21(6):1948–1950. doi:10.1097/SCS.0b013e3181f4ed81

4. Fattah AY, Ravichandiran K, Zuker RM, Agur AM. "A Three-Dimensional Study of the Musculotendinous and Neurovascular Architecture of the Gracilis Muscle: Application to Functional Muscle Transfer." J Plast Reconstr Aesthet Surg. 2013;66(9):1230–1237. doi:10.1016/j.bjps.2013.05.012

5. Morris SF, Yang D. "Gracilis Muscle: Arterial and Neural Basis for Subdivision." Ann Plast Surg. 1999;42(6):630–633. doi:10.1097/00000637-199906000-00008

6. Chancellor MB, Watanabe T, Rivas DA, et al. "Gracilis Urethral Myoplasty: Preliminary Experience Using an Autologous Urinary Sphincter for Post-Prostatectomy Incontinence." J Urol. 1997;158(4):1372–1375. doi:10.1016/s0022-5347(01)64218-6

7. Guo H, Sa Y, Xu Y, Wang L, Fei X. "Adynamic Graciloplasty With a Pedicled Gracilis Muscle Flap Wrapped Around Bulbar Urethra for Treatment of Male Acquired Urinary Incontinence." Urology. 2016;91:208–214. doi:10.1016/j.urology.2015.12.073

8. Guo H, Sa Y, Fu Q, Jin C, Wang L. "Experience With 32 Pelvic Fracture Urethral Defects Associated With Urethrorectal Fistulas: Transperineal Urethroplasty With Gracilis Muscle Interposition." J Urol. 2017;198(1):141–147. doi:10.1016/j.juro.2017.01.071

9. Rozanski AT, Vanni AJ. "Ventral Buccal Mucosa Graft Urethroplasty With Gracilis Muscle Flap for High Risk, Long Segment Urethral Strictures: A 20-Year Experience." Urology. 2020;140:178–180. doi:10.1016/j.urology.2020.03.008

10. Ryan JA, Gibbons RP, Correa RJ. "Urologic Use of Gracilis Muscle Flap for Nonhealing Perineal Wounds and Fistulas." Urology. 1985;26(5):456–459. doi:10.1016/0090-4295(85)90153-0

11. Hasen KV, Gallegos ML, Dumanian GA. "Extended Approach to the Vascular Pedicle of the Gracilis Muscle Flap: Anatomical and Clinical Study." Plast Reconstr Surg. 2003;111(7):2203–2208. doi:10.1097/01.PRS.0000060114.95065.C5

12. Ducic I, Dayan JH, Attinger CE, Curry P. "Complex Perineal and Groin Wound Reconstruction Using the Extended Dissection Technique of the Gracilis Flap." Plast Reconstr Surg. 2008;122(2):472–478. doi:10.1097/PRS.0b013e31817d607d

13. Stewart F, Gameiro LF, El Dib R, et al. "Electrical Stimulation With Non-Implanted Electrodes for Overactive Bladder in Adults." Cochrane Database Syst Rev. 2016;12:CD010098. doi:10.1002/14651858.CD010098.pub4

14. Warehime JM, Gaskins JT, Gupta AS, et al. "Proximity of Percutaneous Tibial Nerve Stimulation Needle Insertion to Surrounding Anatomic Structures: A Cadaveric Study." Am J Obstet Gynecol. 2023;229(4):430.e1–430.e6. doi:10.1016/j.ajog.2023.06.048

15. Panicker JN, Fowler CJ, Kessler TM. "Lower Urinary Tract Dysfunction in the Neurological Patient: Clinical Assessment and Management." Lancet Neurol. 2015;14(7):720–732. doi:10.1016/S1474-4422(15)00070-8

16. Li X, Li X, Liao L. "Mechanism of Action of Tibial Nerve Stimulation in the Treatment of Lower Urinary Tract Dysfunction." Neuromodulation. 2024;27(2):256–266. doi:10.1016/j.neurom.2023.03.017

17. Lee UJ, MacDiarmid S, Matthews CA, Gillespie E, Peters KM. "Tibial Nerve Stimulation for Urge Urinary Incontinence and Overactive Bladder: Narrative Review of Randomized Controlled Trials and Applicability to Implantable Devices." Adv Ther. 2024;41(7):2635–2654. doi:10.1007/s12325-024-02864-3

18. Amarenco G, Ismael SS, Even-Schneider A, et al. "Urodynamic Effect of Acute Transcutaneous Posterior Tibial Nerve Stimulation in Overactive Bladder." J Urol. 2003;169(6):2210–2215. doi:10.1097/01.ju.0000067446.17576.bd

19. Tahmasbi F, Salehi-Pourmehr H, Naseri A, et al. "Effects of Posterior Tibial Nerve Stimulation (PTNS) on Lower Urinary Tract Dysfunction: An Umbrella Review." Neurourol Urodyn. 2024;43(2):494–515. doi:10.1002/nau.25343

20. Deutinger M, Kuzbari R, Paternostro-Sluga T, et al. "Donor-site morbidity of the gracilis flap." Plast Reconstr Surg. 1995;95(7):1240–1244. doi:10.1097/00006534-199506000-00015

21. American Urological Association / Society of Urodynamics, Female Pelvic Medicine & Urogenital Reconstruction. Diagnosis and Treatment of Idiopathic Overactive Bladder. 2024. Guideline Statement 25 and treatment framework.

22. US Food and Drug Administration. NURO Neuromodulation System 510(k) summary K132561. 2013. Device comparison with Urgent PC, pp. 2–3.

23. Anderson BW, Ekblad J, Bordoni B. Anatomy, Abdomen and Pelvis, Obturator Nerve. StatPearls. NCBI Bookshelf. Accessed September 20, 2026.

24. US Food and Drug Administration. Revi System De Novo Classification Request, DEN220073. 2023; pp. 1–2.

25. Valencia Technologies Corporation. eCoin Peripheral Neurostimulator System: eCoin Physician Manual, model UUI. Document 903-1225, revision PB; pp. 50, 53–57.

26. Soper JT, et al. "Long and Short Gracilis Myocutaneous Flaps for Vulvovaginal Reconstruction After Radical Pelvic Surgery: Comparison of Flap-Specific Complications." Gynecol Oncol. 1995;56(2):271–275. doi:10.1006/gyno.1995.1045

27. Lacey CG, et al. "Vaginal Reconstruction After Exenteration With Use of Gracilis Myocutaneous Flaps: The University of California, San Francisco Experience." Am J Obstet Gynecol. 1988;158(6 Pt 1):1278–1284. doi:10.1016/0002-9378(88)90357-2

28. Omarov N, Tatar S. "The Repairing of the Recto-Neovaginal Fistula in a Male-to-Female Transgender Through Perineal Graciloplasty." Cureus. 2021;13(6):e15784. doi:10.7759/cureus.15784

29. Kim H, Kim WK, Kim YS, Nam YS. "Morphologic classification and innervation patterns of the pectineus muscle." Anat Sci Int. 2021;96(4):524–530. doi:10.1007/s12565-021-00619-6

30. Brush E, Hernandez JA, Flusché AM, et al. "The Uroplastic Approach to Complex Rectourethral Fistula Repair: Indications, Technique, Results." Plast Reconstr Surg Glob Open. 2025;13(4):e6662. doi:10.1097/GOX.0000000000006662

31. Maspero M, Otero Piñeiro A, Steele SR, Hull TL. "Gracilis Muscle Interposition for the Treatment of Rectovaginal Fistula: A Systematic Review and Pooled Analysis." Dis Colon Rectum. 2023;66(5):631–645. doi:10.1097/DCR.0000000000002739

32. European Association of Urology. EAU Guidelines on Non-neurogenic Female LUTS, disease management §4.1.4.a.5.d.1 and summary of evidence. 2026. Guideline.

33. Peters KM, Carrico DJ, Perez-Marrero RA, et al. "Randomized trial of percutaneous tibial nerve stimulation versus sham efficacy in the treatment of overactive bladder syndrome: results from the SUmiT trial." J Urol. 2010;183(4):1438–1443. doi:10.1016/j.juro.2009.12.036

34. Gupta P, Ehlert MJ, Sirls LT, Peters KM. "Percutaneous tibial nerve stimulation and sacral neuromodulation: an update." Curr Urol Rep. 2015;16(2):4. doi:10.1007/s11934-014-0479-1

35. Amundsen CL, Sutherland SE, Heesakkers JPFA, et al. "Three-Year Efficacy and Safety of Revi Implantable Tibial Neuromodulation from the Pivotal OASIS Study." J Urol. 2026;216(2):219–229. doi:10.1097/JU.0000000000005062