**Region:** Lower Extremity # Superficial Femoral Artery Flap ## Anatomy - Pedicle: There is no dedicated “superficial femoral artery (SFA) flap” described in the provided sources. The closest relevant data note that the superficial circumflex iliac artery (SCIA) system — the basis for the groin/SCIP flap — may arise directly from the superficial femoral artery in some cases (Groin/SCIP chapter). Relevant numeric data from those chapters (applicable when the SCIA is the target vessel): - SCIA diameter: 0.8–1.8 mm (SCIA system). - Dominant SCIP perforator: typically located ~1.5–3 cm superomedial to the ASIS; mean perforator diameter ≈ 0.85 mm. - SCIP pedicle mean length: 4.8 ± 1.3 cm (range 3–8 cm); microdissection can yield a mean length ≈ 7 cm. - When considering posterior thigh/gluteal-based flaps, the descending branch of the inferior gluteal artery (used for gluteal/thigh flaps) has been reported with a mean arterial caliber ≈ 1.33 mm and flap dimensions up to 12–15 cm width × up to 30 cm length (gluteal thigh references). - Lateral femoral circumflex artery (LFCA) (relevant to ALT flaps): caliber ≈ 2–3 mm; pedicle length ≈ 8 cm (varies by perforator). - Course: No explicit SFA-based flap course is described in the attached texts. The only directly relevant course statement is that the SCIA may originate from the superficial femoral artery; SCIA then divides into superficial and deep branches and courses superolaterally toward the ASIS (Groin/SCIP chapter). For posterior thigh/gluteal flaps, the descending branch of the inferior gluteal artery exits beneath gluteus maximus and courses subfascially down the middle of the posterior thigh to the knee (Posterior thigh / Gluteal thigh chapters). - Perforator pattern: - SCIA/SCIP: perforators may be superficial or deep branch perforators; the dominant perforator commonly around 1.5–3 cm superomedial to the ASIS; superficial branch perforates deep fascia immediately after origin (Groin/SCIP chapter). The superficial branch can be hypoplastic/absent; deep branch commonly present and provides multiple muscle perforators. - ALT: perforators are mostly musculocutaneous (~80%) through vastus lateralis; septocutaneous perforators more likely proximally; primary (“B”) perforator usually at midpoint of ASIS–lateral patella axis (Anterolateral thigh chapter). - Posterior thigh/gluteal thigh: multiple cutaneous perforators along the descending branch of inferior gluteal artery; posterior femoral cutaneous nerve often runs in same sheath (~72% reported) (Posterior thigh chapter). - Venae comitantes / venous drainage: - SCIA concomitant vein drains to femoral vein; superficial cutaneous veins run parallel and drain toward greater saphenous; superficial medial cutaneous vein of SCIP may be included to augment venous outflow when concomitant vein caliber is small (< 0.5 mm) (Groin/SCIP chapter). - Gluteal thigh flaps have redundant venous drainage (deep system, venae comitantes of inferior gluteal and deep femoral perforators, superficial veins); venous congestion is uncommon (Gluteal thigh chapter). - Nerves: - SCIP/groin: lateral femoral cutaneous nerve crosses the deep branch; sensate SCIP flaps have been described using lateral cutaneous branches (Groin/SCIP chapter). - ALT: lateral femoral cutaneous nerve (L2–L3) emerges ~10 cm below ASIS and may be included for sensate flaps (Anterolateral thigh chapter). - Posterior/gluteal thigh: posterior femoral cutaneous nerve (S1–S3) runs with inferior gluteal system and provides potential for sensate flap (Posterior thigh / Gluteal thigh chapters). - Included tissues and thickness profile: - SCIP/groin: fasciocutaneous; can be elevated suprafascially to harvest a thinner flap or at the level of superficial fascia preserving deep adipose tissue; flap dimensions reported up to 25 cm length and up to 8–10 cm width (Groin/SCIP chapter). - ALT: fasciocutaneous (workhorse flap); can be thinned (superthin) or include vastus lateralis muscle (myocutaneous); typical width for primary closure ≈ 8 cm (Anterolateral thigh chapter). - Posterior/gluteal thigh: fasciocutaneous; can include inferior fibers of gluteus maximus as a myocutaneous component when extra bulk or pedicle length is needed (Posterior thigh / Gluteal thigh chapters). - Arc of rotation / common variants: - No explicit SFA-based flap arc reported. For SCIP, pedicle can be dissected distally and skin paddle moved lateral to ASIS to increase pedicle length; superficial branch present >90% but may be absent — deep branch is a reliable alternative (Groin/SCIP chapter). - Posterior thigh/gluteal thigh flaps: island or rotation/pedicle designs; pedicle length can be increased by including inferior gluteal artery proximally (gluteal thigh variant). ## Dissection Steps 1. Positioning, markings, landmarks. - Preoperative Doppler: use handheld Doppler to identify SCIA/SCIP perforators and course (recommended in Groin/SCIP chapter). For ALT, mark ASIS and lateral patella; perforator “B” at midpoint (Anterolateral thigh chapter). - Patient position: SCIP/groin – supine with hip slightly elevated; gluteal/posterior thigh – prone or lithotomy (position selection depends on defect and inset; gluteal markings easier when patient prone/standing) (Groin/SCIP, Posterior thigh, Gluteal thigh chapters). - Surface landmarks when SCIA involved: SCIA runs ~2–3 cm inferior and parallel to inguinal ligament; SCIA system origin within triangle bounded by lateral border of adductor longus medially, inguinal ligament superiorly, medial border of sartorius laterally (Groin/SCIP chapter). When planning posterior/gluteal thigh harvest, center flap over line midway between greater trochanter and ischial tuberosity; distal extent usually not beyond popliteal crease for gluteal thigh (Gluteal thigh, Posterior thigh chapters). 2. Plane (suprafascial/subfascial), perforator identification (handheld/IO Doppler). - SCIP: elevate in suprafascial plane “freestyle” from lateral → medial after choosing dominant perforator; first incision through inferior or superior border to visualize superficial or deep branch perforators (Groin/SCIP chapter). - ALT: perform subfascial dissection medially → laterally to reach intermuscular septum and descending branch of LFCA; perforators are commonly musculocutaneous and require intramuscular dissection (Anterolateral thigh chapter). - Posterior thigh/gluteal thigh: elevate from distal → proximal in subfascial plane, include deep fascia; preserve hamstring muscles and visualize pedicle in mid-distal thigh (Posterior thigh, Gluteal thigh chapters). - Use handheld Doppler to confirm perforators and course (Groin/SCIP; ALT). 3. Pedicle dissection: exposure, control, division; transfer/inset; perfusion checks. - SCIP pedicle dissection: once dominant perforator identified, dissect from lateral → medial in suprafascial plane; include cutaneous (medial) superficial vein if concomitant vein is small; pedicle length typically 3–8 cm (mean 4.8 ±1.3 cm), microdissection can increase length to ~7 cm (Groin/SCIP chapter). - ALT pedicle dissection: open septum between rectus femoris and vastus lateralis to expose descending branch of LFCA; if musculocutaneous perforator chosen, dissect through vastus lateralis to the source vessel; pedicle clipped distally and freed to pedicle origin as needed (Anterolateral thigh chapter). - Posterior thigh/gluteal thigh pedicle: elevate distal → proximal to include descending branch of inferior gluteal artery; for increased reach, divide inferior gluteus maximus fibers and follow pedicle proximally to origin (Posterior thigh / Gluteal thigh chapters). Ensure no twisting/kinking during rotation/inset. - Perfusion assessment: intraoperative indocyanine green (ICG) fluorangiography has been used to assess gluteal thigh flap perfusion (Gluteal thigh chapter). 4. Donor-site closure techniques. - Primary closure: SCIP/groin donor site primary closure possible if width ≲ 8–10 cm; closed suction drain recommended (Groin/SCIP chapter). ALT donor site typically closable if width <8 cm; consider “purse-string” dermal running suture to minimize graft size (Anterolateral thigh chapter). - If primary closure not possible: plan split-thickness skin grafting. Place closed-suction drains beneath flap and at donor site when indicated (SCIP, ALT, Posterior thigh, Gluteal thigh chapters). - Prevent shearing: temporary tacking sutures between skin and fascia lata during gluteal thigh elevation (Gluteal thigh chapter). ## Indications and Contraindications - Indications (derived from described analogous flaps in the provided sources): - Small-to-moderate cutaneous defects requiring thin fasciocutaneous coverage where a groin/SCIP or adjacent thigh flap is suitable (SCIP/groin chapter): dorsal hand, distal forearm, foot/ankle, genital area, upper extremity, cheek/floor of mouth, and perineal resurfacing. - Perineal, ischial, sacral defects and pressure sores commonly reconstructed with posterior thigh/gluteal thigh flaps (Posterior thigh, Gluteal thigh chapters). - Need for sensate flap: SCIP and posterior thigh/gluteal thigh techniques permit inclusion of cutaneous nerves for sensate reconstruction when anatomy permits (Groin/SCIP; Posterior thigh). - Contraindications: - Significant ipsilateral arterial disease or prior vessel sacrifice that compromises the relevant arterial supply (general principle; specific cases of SCIA hypoplasia or absence are reported for SCIP) (Groin/SCIP chapter). - Prior surgery or radiation that has interrupted the intended pedicle or perforators — e.g., prior inferior gluteal or thigh flap harvest may have transected the descending branch (Posterior thigh, Gluteal thigh chapters). - Patient comorbidities that preclude flap transfer/positioning or increase risk of poor healing (tobacco, poorly controlled diabetes) — cited as preoperative optimization points (Posterior thigh chapter). ## Postoperative Care - Monitoring schedule/method: - Use clinical monitoring (color, capillary refill, turgor) complemented by handheld Doppler as indicated (SCIP/ALT/posterior thigh & gluteal thigh texts emphasize Doppler for planning; clinical monitoring is standard though specific schedules are not detailed in these chapters). - ICG fluorangiography can be used intraoperatively to assess flap perfusion for gluteal thigh flaps (Gluteal thigh chapter). - Warming/antithrombotic practice: - Specific antithrombotic regimens are not detailed in the provided chapters. - Positioning/splinting: - For perineal/gluteal thigh reconstructions: avoid sitting for 2–3 weeks; recommend air‑fluidized mattress and frequent turning to decrease pressure sore risk (Gluteal thigh chapter). - For general lower-extremity thigh flap harvests: early mobilization restricted per flap type — gluteal thigh chapters recommend ~48-hour recovery before strenuous leg movements (Gluteal thigh chapter). - Drains, mobilization, diet/analgesia: - Place closed-suction drains beneath flap and at donor site when indicated (SCIP/ALT/posterior thigh/gluteal thigh chapters). Routine drain care and vigilance for infection are emphasized (Gluteal thigh chapter). - Analgesia and diet not specifically detailed in these chapters. - Return-to-OR thresholds and time windows: - The provided texts do not specify precise numeric thresholds or time windows for re-exploration. Standard practice (not specified here) would be guided by clinical signs of ischemia or venous congestion and by available monitoring modalities; the sources do not supply explicit re-exploration algorithms. ## Complications (rates & management) - Reported complication rates (from gluteal thigh / posterior thigh clinical series within the provided sources): - Walton et al. (gluteal thigh series): 46 patients, 8 total complications; 2 total flap failures (one thrombosed inferior gluteal artery; one attempted free flap with venous thrombosis). - Achauer et al. (gluteal thigh): 2 cases of delayed healing in 7 flaps. - Friedman et al.: series of 27 flaps — 1 failure reported; in a subgroup 10 of 19 experienced delayed wound healing. - Saito et al.: series of 8 patients — 1 total flap loss and 2 partial losses. - SCIP/groin flap complications: wound dehiscence, seroma, lymphorrhea are noted as rare complications, especially when lymphatics are transected (Groin/SCIP chapter). - Specific complications described: - Venous congestion: stated to be uncommon for gluteal thigh flaps due to redundant venous drainage (Gluteal thigh chapter). SCIP may require inclusion of superficial medial cutaneous vein to augment venous outflow when concomitant veins are small (<0.5 mm) (Groin/SCIP chapter). - Arterial thrombosis: reported as cause of flap failure in case series (Gluteal thigh outcomes). - Partial/total loss, infection, fat necrosis: recorded in various series for gluteal/posterior thigh flaps; exact management algorithms are not detailed in the provided texts. - Donor-site issues: seroma, wound dehiscence, lymphorrhea (noted for SCIP/groin when full-thickness subcutaneous fat or groin lymphatics are included); contour deformity and closure difficulty noted where flap width exceeds primary closure limits (Groin/SCIP; ALT; Posterior thigh chapters). - Management: - The attached sources describe identification and avoidance of risk factors (optimize tobacco, glucose control) and standard measures (drains, tension‑free closure, use of skin grafts when primary closure impossible). Specific salvage algorithms (leeching, thrombolysis, timing for re‑exploration) are not detailed in these chapters. ## Key Clinical Pearls - SCIP / Groin–related pearls: - The SCIA may arise from the superficial femoral artery, external iliac artery, or in common trunk with DCIA — anticipate anatomical variability and confirm with Doppler or preoperative imaging when needed (Groin/SCIP chapter). - SCIA diameter typically 0.8–1.8 mm; dominant perforator usually ~0.85 mm and located ~1.5–3 cm superomedial to the ASIS (Groin/SCIP chapter). - SCIP pedicle mean length ≈ 4.8 ±1.3 cm (3–8 cm); microdissection can lengthen to ≈ 7 cm — plan recipient site accordingly and consider need for vein graft if >7 cm arterial reach required (Groin/SCIP chapter). - Include superficial cutaneous vein medially if concomitant vein caliber is too small (<0.5 mm) to ensure adequate venous outflow (Groin/SCIP chapter). - ALT / thigh flap pearls: - Perforator “B” is typically at the midpoint of ASIS–lateral patella axis (often 1.5 cm posterior to midpoint); “A” ≈ 5 cm proximal, “C” ≈ 5 cm distal — use these as reliable mapping points and confirm with Doppler (Anterolateral thigh chapter). - LFCA caliber ≈ 2–3 mm; pedicle length commonly ≈ 8 cm but varies with perforator choice — distal perforators generally provide longer pedicle reach (Anterolateral thigh chapter). - If ALT perforators are inadequate, consider anteromedial thigh (AMT) perforators or include vastus lateralis muscle (myocutaneous) to secure perfusion (Anterolateral thigh chapter). - Posterior / gluteal thigh pearls: - Posterior femoral cutaneous nerve is within the same connective tissue sheath as the descending inferior gluteal vessels ≈72% of the time — harvest can be sensate when nerve included (Posterior thigh chapter). - Mark the midpoint between greater trochanter and ischial tuberosity as the approximate exit of the descending branch beneath gluteus maximus (Posterior thigh / Gluteal thigh chapters). - For perineal/gluteal reconstructions: avoid sitting for 2–3 weeks postoperatively; use air‑fluidized mattress and frequent turning to reduce pressure sore risk (Gluteal thigh chapter). - Donor closure and sizing: - Plan flap width to permit primary donor-site closure: SCIP/ groin and ALT generally ≲ 8–10 cm for primary closure; posterior/gluteal thigh primary closure width ≈ 10–12 cm depending on habitus (Groin/SCIP; ALT; Posterior thigh chapters). - When planning long pedicle reach, mapping and suprafascial dissection can help thin flap and extend reach (SCIP/ALT chapters). - Safety tips: - Do not rely solely on posterior femoral cutaneous nerve as a landmark for inferior gluteal pedicle orientation — distal arborization is common (Gluteal thigh chapter). - Place temporary tacking sutures between skin and fascia to prevent shearing during flap mobilization (Gluteal thigh chapter). - Use preoperative Doppler or color Doppler/CTA when anatomical variability is suspected or when precise pedicle mapping will change the operative plan (Groin/SCIP; ALT chapters).