**Region:** Groin and Gluteal # Gluteal Thigh Flap ## Anatomy - Pedicle: descending (terminal) branch of the inferior gluteal artery (terminal cutaneous branch arising beneath gluteus maximus). Mean arterial caliber reported as 1.33 mm. Venae comitantes accompany the artery; multiple cutaneous perforators arise along its course. The descending branch: - courses deep to gluteus maximus, exits to the posterior thigh at the midpoint of the inferior gluteal border, then runs subfascially down the middle of the posterior thigh toward the popliteal region, staying above and between biceps femoris laterally and semitendinosus medially (posterior cutaneous perforators present along entire course) (Posterior Thigh Flap; Gluteal Thigh Flaps). - distal-most territory may receive contribution/anastomoses from medial femoral circumflex or other thigh perforators in an anastomotic plexus; absence of the descending inferior gluteal branch is a described variation (Gluteal Thigh Flaps). - Perforator pattern: multiple cutaneous perforators along the descending branch; proximal perforators are robust, and the vessel gives off musculocutaneous and septocutaneous branches to skin/subcutis. The terminal branch may be encountered at the distal flap margin and can require ligation (Gluteal Thigh Flaps; Posterior Thigh Flap). - Angiosomes and choke vessels: anastomotic plexus at level of medial femoral circumflex artery provides collateral flow; superficial gluteal perforators form an additional plexus (Gluteal Thigh Flaps). - Nerves: - Posterior femoral cutaneous nerve runs within the same connective tissue sheath as the vascular pedicle in the posterior thigh approximately 72% of the time — can be included to create a sensate flap (Posterior Thigh Flap). - Sciatic nerve lies deep and superior to the flap dissection (identified and preserved during proximal dissection) (Gluteal Thigh Flaps). - Included tissues: skin + subcutaneous tissue + investing fascia lata; flap may be elevated fasciocutaneously or as a myocutaneous variant including the inferior portion of gluteus maximus (to level of piriformis) when extra bulk or arc of rotation is required (Gluteal Thigh Flaps; Posterior Thigh Flap). - Flap dimensions (reported): - practical donor width allowing primary closure commonly ~10–12 cm depending on habitus; flaps can be designed up to 12–15 cm wide and up to ~30 cm long in larger designs (Gluteal Thigh Flaps; Posterior Thigh Flap). - distal extent may be planned to within 8 cm of the popliteal fossa (Gluteal Thigh Flaps). - Arc of rotation: flap can reach ipsilateral ischial tuberosity, perineum, posterior/lateral vaginal wall, sacrum; can be tunneled subcutaneously to anterior/perineal defects; additional pedicle length obtained by including the inferior gluteal artery and releasing gluteus maximus attachments when necessary (Posterior Thigh Flap; Gluteal Thigh Flaps). - Common variants/anomalies: absent descending inferior gluteal branch with cutaneous supply from medial circumflex femoral or other perforators; occasional double main pedicle or variable origin (<10% of time descending branch may arise from profunda, medial circumflex, or lateral circumflex — posterior thigh variations) (Gluteal Thigh Flaps; Posterior Thigh Flap). ## Dissection Steps 1. Positioning, markings, landmarks. - Position: prone for harvest; if flap will be inset to an anterior/perineal defect the patient may be repositioned supine for inset, or harvest + inset may be performed in exaggerated lithotomy when appropriate (Gluteal Thigh Flaps). - Landmarks and markings: - identify gluteal crease and draw a line midway between greater trochanter and ischial tuberosity — the descending branch exits beneath gluteus maximus at this midpoint; center flap axis along a line connecting that exit point to the popliteal fossa center (Posterior Thigh Flap; Gluteal Thigh Flaps). - design skin paddle to fill defect while aiming to allow primary donor closure (pinch test). Typical safe widths for direct closure ~10–12 cm; maximal planned widths up to 12–15 cm (Gluteal Thigh Flaps). - distal extent: can extend to within ~8 cm of popliteal fossa when needed (Gluteal Thigh Flaps). - mark orientation perpendicular to gluteal crease and centered over posterior thigh axis. 2. Plane, perforator identification. - Plane of dissection: subfascial (deep to fascia lata) elevation is recommended. Elevation in the correct plane preserves perforators and protects the pedicle. Suprafascial dissection risks pedicle injury and is discouraged (Posterior Thigh Flap; Gluteal Thigh Flaps). - Perforator identification: a handheld Doppler may be used pre- or intraoperatively to confirm the descending branch/perforators in the mid-posterior thigh. Expect multiple cutaneous perforators along vessel course; terminal branch may be encountered distally (Posterior Thigh Flap; Gluteal Thigh Flaps). - Technique: incise distal border first, carry skin/subcutaneous/fascia incision through to expose hamstring fascia; elevate flap from distal to proximal in continuity with the skin paddle off the hamstring muscles, staying in the subfascial plane so the pedicle/perforators are preserved (Posterior Thigh Flap). - Prevent shearing between skin and fascia by placing temporary tacking sutures between skin and fascia lata as elevation proceeds (Gluteal Thigh Flaps). 3. Pedicle dissection: exposure, control, division; transfer/inset; perfusion checks. - Distal→proximal elevation until pedicle visualized (often in mid- to distal third); follow pedicle proximally to the inferior margin of gluteus maximus (Posterior Thigh Flap). - If additional pedicle length required: divide inferior attachments of gluteus maximus and trace pedicle proximally to include inferior gluteal artery; exercise caution in ambulatory patients when releasing gluteus maximus (Posterior Thigh Flap; Gluteal Thigh Flaps). - Ligate and divide any deep femoral perforators encountered during proximal mobilization. The terminal branch encountered at the distal flap margin may require ligation during elevation (Gluteal Thigh Flaps). - Preserve posterior femoral cutaneous nerve when a sensate flap is desired — the nerve is often in the same sheath as the descending branch and can be included with the flap (Posterior Thigh Flap). - Maintain venous drainage: consider leaving a medial or lateral cutaneous skin bridge where venous outflow may be enhanced, or avoid full islanding if venous drainage is a concern (Posterior Thigh Flap). - Transfer/inset: rotate/advance the flap into the defect without twisting or kinking the pedicle; deepithelialize proximal/distal ends as needed to fill dead space or create padding for pressure areas (Posterior Thigh Flap). - Perfusion checks: clinical assessment (color, capillary refill, bleeding at flap edge) is the primary check described in source texts; ensure flap appears viable without ischemia or venous congestion after inset (Gluteal Thigh Flaps). 4. Donor-site closure techniques. - Layered, linear closure over closed-suction drain(s) is standard when primary closure feasible. Limit undermining to preserve lymphatics and reduce risk of lymphedema (Posterior Thigh Flap; Gluteal Thigh Flaps). - If width too large for primary closure, plan split-thickness skin graft to donor site. - Secure superficial fascia of lower wound edge to Colles’ (superior) fascia when closing medial thigh inferiorly to reduce scar migration and traction (Gluteal Thigh Flaps). - Place at least one closed-suction drain beneath flap to avoid seroma/hematoma (Gluteal Thigh Flaps; Posterior Thigh Flap). ## Indications and Contraindications - Indications: - Pressure sore (ischial) reconstruction (workhorse flap). - Perineal reconstruction: vulvar, perianal, posterior/inferior vaginal wall defects, pelvic outlet filling. - Sacral and lateral thigh/hip defects. - When sensate coverage is desired, include posterior femoral cutaneous nerve (Posterior Thigh Flap; Gluteal Thigh Flaps). - Useful when regional tissue required with reliable muscle/padded coverage and when alternatives (e.g., local gluteal rotation) are unavailable or previously used. - Size limits and tissue character: - Flap may be designed up to ~12–15 cm width and up to ~30 cm length in larger reconstructions; practical donor widths allowing primary closure are generally ~10–12 cm (Gluteal Thigh Flaps). - Fasciocutaneous (thin-to-moderate thickness) — myocutaneous variant including inferior gluteus maximus can provide additional bulk. - Contraindications: - Prior harvest or surgery that has divided the descending branch or inferior gluteal perforators (e.g., prior gluteal rotation or inferior gluteal perforator flap) unless pedicle anatomy confirmed. - Active infection not controlled or poor local tissue bed (need to control infection prior to definitive reconstruction). - Severe peripheral vascular disease affecting the supplying vessels or anatomic absence of the descending branch (variation); verify anatomy when in doubt (Gluteal Thigh Flaps; Posterior Thigh Flap). - Ambulatory patients in whom resection of significant gluteus maximus for extra reach would compromise gait — exercise caution with extensive muscle harvest (Posterior Thigh Flap). ## Postoperative Care - Monitoring: clinical flap checks (color, capillary refill, turgor) — sources describe clinical monitoring as the method; closed-suction drains are routinely left under the flap (Gluteal Thigh Flaps; Posterior Thigh Flap). - Drain management: closed-suction drainage beneath flap and at donor site; ensure drains remain functional to prevent seroma/hematoma (Gluteal Thigh Flaps). - Positioning and pressure off-loading: - Prone positioning is usual initially; for ischial/pressure sore reconstructions, strict pressure-avoidance and wheelchair mapping are emphasized prior to resuming sitting to protect the repair (Posterior Thigh Flap). - For perineal tunneling/inset, manage positions according to inset requirements; repositioning intraop (prone↔supine) may be required for inset of anterior defects (Gluteal Thigh Flaps). - Mobilization and rehabilitation: - Early, supervised mobilization as allowed by surgical team and defect specifics; avoid direct pressure on reconstructed area until healed and mapped seating cushions are adjusted (Posterior Thigh Flap). - Antithrombotic practice, warming, implantable probes, analgesia, diet: not specified in the provided sources; follow institutional protocols. - Return-to-OR thresholds/time windows: - No explicit time windows detailed in sources. Return to OR should be considered for signs of flap ischemia, progressive venous congestion, hematoma compromising perfusion, or wound dehiscence per standard reconstructive principles. ## Complications (rates & management) - Reported frequencies: specific flap failure or complication percentages are not provided in the supplied chapters for this flap. The sources do report: - Posterior femoral cutaneous nerve is in the pedicle sheath approximately 72% of the time (Posterior Thigh Flap). - Typical complications described and management principles: - Venous congestion: mitigate by preserving skin bridges/avoiding excessive islanding, avoid pedicle kinking; if progressive congestion occurs, consider prompt re-exploration to relieve pedicle twist or hematoma (Posterior Thigh Flap). - Arterial insufficiency: inspect for pedicle torsion/kinking; urgent return to OR for exploration if signs of arterial compromise appear (Gluteal Thigh Flaps). - Partial flap loss / distal tip necrosis: larger distal extensions increase risk; plan flap within reliable angiosome and limit distal extent to safe margins (e.g., within 8 cm of popliteal fossa as described) and consider deepithelialization or secondary grafting if distal tissue uncertain (Gluteal Thigh Flaps). - Infection/contamination: in pressure sore reconstructions, optimize local infection control before definitive closure; manage postoperative infection with antibiotics, drainage, and debridement as indicated. - Donor-site problems: seroma/hematoma — closed-suction drains recommended; tension leading to wound dehiscence — limit flap width to allow primary closure or graft if needed; if primary closure under tension fails, skin graft over donor site may be required (Gluteal Thigh Flaps). - Sciatic/pudendal nerve injury: identify and preserve sciatic nerve during proximal dissection; avoid injuring pudendal vessels near ischial tuberosity (Gluteal Thigh Flaps). - Management algorithms: - Hematoma under flap: evacuate urgently, control bleeding, reassess pedicle perfusion. - Pedicle twist/kink: urgent exploration, release twist, possibly revise inset or reorient flap. - Venous congestion where re-exploration not feasible: consider medical measures per institutional protocols (not specifically detailed in sources). - Donor-site seroma: manage with drainage and compression, consider re-insertion of closed-suction drain if persistent. ## Key Clinical Pearls - Mark the flap centered over the line midway between greater trochanter and ischial tuberosity; the descending branch exits beneath gluteus maximus at that midpoint — plan axis toward the popliteal center (Posterior Thigh Flap; Gluteal Thigh Flaps). - Elevate the flap in a subfascial plane from distal to proximal; avoid suprafascial elevation which risks pedicle injury (Posterior Thigh Flap). - Place temporary tacking sutures between skin and fascia lata during elevation to prevent shearing of skin from deep tissues (Gluteal Thigh Flaps). - Preserve a medial or lateral skin/subcutaneous bridge or avoid full islanding if venous drainage is a concern — this reduces the risk of venous congestion (Posterior Thigh Flap). - Include the posterior femoral cutaneous nerve when a sensate flap is desired; it runs with the vasculature in roughly 72% of cases (Posterior Thigh Flap). - If extra bulk or arc is required, include the inferior gluteus maximus (to level of piriformis) as a myocutaneous extension — but in ambulatory patients avoid extensive gluteus maximus release to prevent gait disturbance (Gluteal Thigh Flaps; Posterior Thigh Flap). - Donor closure: plan flap width to allow primary closure (practical ~10–12 cm); otherwise be prepared for skin grafting; always place closed-suction drains beneath flap (Gluteal Thigh Flaps). - Distal planning: avoid overextending the distal flap beyond reliable angiosome limits; the distal flap can be deepithelialized to fill cavities or provide padding for ischial defects (Gluteal Thigh Flaps; Posterior Thigh Flap).