**Region:** Trunk and Lower Back # Superior Epigastric Artery Perforator Flap ## Anatomy - Pedicle: superior epigastric artery (SEA) — terminal branch of the internal mammary artery; gives musculocutaneous perforators through rectus abdominis toward the upper/central abdomen. SEA enters rectus at the costal margin; first large perforator often at the costal margin (sometimes termed the deep/superficial superior epigastric artery). Pedicle is shorter and of smaller caliber than the deep inferior epigastric system (SEA pedicle dissection typically stops near the costal margin). (Uemura; Hamdi) - Perforator topography (Uemura cadaver data): perforators per hemiabdomen range 1–3; mean distance from midline 35 mm (range 10–82 mm); mean distance from inferior costal margin 26 mm (range 12–50 mm). - Additional clinical cadaver/clinical ranges: SEAPs found 1.5–6.5 cm lateral to midline and 3–16 cm below a horizontal line centered at the xiphisternum (Hamdi). - Angiosome/choke connections: SEA arborizes within rectus and meets DIEA system caudally at choke anastomoses or occasionally true arterial connections at about the midpoint between xiphoid and umbilicus (Taylor & Palmer; Uemura). - Perforator pattern: most SEAP perforators are musculocutaneous (pass through rectus muscle). Perforators cluster in a trapezoid bounded medially by midline, laterally by medial half of rectus, superiorly by costal margin, inferiorly by horizontal midpoint between xiphoid and umbilicus (SEAP territory). Most perforators are in the medial half of the muscle above the midpoint between xiphoid and umbilicus (peri‑xiphisternal). - Venous drainage: venae comitantes accompany SEA perforators; venous outflow generally through accompanying veins to internal mammary venous system. SEA system can be affected by prior internal mammary harvest. - Nerves: 10th–12th intercostal nerve sensory branches may run with perforators and can be dissected for potential sensate reconstruction (rarely used because requires more intramuscular work). Motor nerves to rectus do not arise from SEA but from segmental intercostals; preserve motor branches when possible to maintain rectus function. - Included tissues: skin, subcutaneous fat (adipocutaneous); fascia and muscle are preserved if desired by limiting intramuscular dissection to the perforator pathway. Thickness profile variable (upper abdomen); flap is suitable where thin-to-moderate bulk is required. Arc of rotation: local pedicled SEAP flaps can reach adjacent anterior chest wall / epigastric defects (propeller rotation 90–180° described) — shorter pedicle limits distant reach; harvest as island or propeller. Common variants/anomalies: perforator number and position highly variable; contralateral reach is unreliable (limited cross‑midline perfusion). ## Dissection Steps 1. Positioning, markings, landmarks. - Position: supine. Palpate xiphoid tip and umbilicus; draw midline vertical from xiphoid to umbilicus. Mark costal margins and an approximate vertical line through the nipple to approximate lateral border (linea semilunaris). Draw horizontal line midway between xiphoid and umbilicus to define inferior limit of reliable SEAP territory. Define trapezoid for each hemiabdomen bounded superiorly by costal margin, inferiorly by the mid‑xiphoid/umbilicus line, medially by midline, laterally by medial half of rectus (▶ Fig. 30.2). - Preop perforator mapping: multidetector CT angiography preferred for precise localization; handheld Doppler is an acceptable alternative for mapping perforators intraoperatively. Mark chosen perforator(s) on skin. - Flap axis: typically oriented parallel/oblique to costal margin; orientation (vertical, oblique, transverse) tailored to defect and donor closure needs. 2. Plane (suprafascial/subfascial), perforator identification (handheld/IO Doppler). - Exploratory incision: make incision along the cephalic border of the planned flap down to anterior rectus sheath to confirm perforator position. - Suprafascial dissection: elevate flap suprafascially until perforators are encountered. Identify perforator(s) and confirm pulsatility/size. For SEAP, perforators are usually encountered within the trapezoidal zone; most are musculocutaneous and will plunge into rectus. - If mapping uncertain, adjust flap boundaries after direct visualization. Avoid undermining beyond planned margins until perforator adequacy is confirmed. 3. Pedicle dissection: exposure, control, division; transfer/inset; perfusion checks. - Anterior rectus sheath: open carefully above and below the chosen perforator to expose entry point into rectus. - Intramuscular dissection: split rectus muscle fibers longitudinally in line with the perforator’s intramuscular course; follow perforator cranially toward the costal margin. If extra pedicle length is required, split along an intramuscular septum and dissect toward SEA source at costal margin. Maintain meticulous hemostasis; use small bipolar cautery and fine scissors. Preserve motor branches to rectus where possible. - If multiple perforators are planned, connect fascial windows and dissect in the same perimysial plane when possible to minimize muscle injury. - Pedicle length: expect a shorter pedicle than DIEA flaps; dissection usually proceeds to costal margin. Take slightly longer pedicle than immediately necessary to avoid twisting/tension in inset. - Intraoperative tests: - Confirm pulsatility and venous drainage. - If in doubt about sufficiency of SEA, consider temporary clamping of adjacent DIEA perforators (if available) to observe perfusion by SEA (strategy described for SIEA → DIEP conversion logic can be applied conceptually to test perfusion dynamics). - Division: once recipient vessels are prepared and flap perfusion satisfactory, divide pedicle and transfer flap. - Insetting: orient pedicle to avoid kinking; for propeller rotation note perforator twist and relieve torsion or widen fascial window as needed. Secure flap with a few absorbable sutures (fix fascia/Scarpa to chest wall if reconstructing breast/chest) to minimize traction/avulsion. - Perfusion checks: clinical observation; avoid overly tight dressings/bandages that may compress pedicle. (Video/illustrations emphasize testing and ensuring unobstructed pedicle curve.) 4. Donor-site closure techniques. - Primary closure preferred. Flex operating table to decrease tension on midline closure. - Reapproximate Scarpa’s fascia and subcutaneous layers to obliterate dead space (tacking sutures). Close skin in layers; subcutaneous 3–0/dermal 3–0 absorbable and subcuticular 3–0 absorbable (notations from SIEA donor closure). - Drains: place suction drains (e.g., two 19 French Blake drains for SIEA donor described) exiting suprapubically as needed. - Preserve remaining superior epigastric perforators and lateral intercostal perforators where possible to reduce donor‑site morbidity. - Consider neo‑umbilicus creation in delayed fashion if cosmetic result preferable. ## Indications and Contraindications - Indications: - Local reconstruction of upper midline/epigastric and lower sternal/xiphoid chest wall defects where a local perforator flap will suffice. - Small-to-moderate soft tissue defects of the anterior chest wall, xiphoid region, and upper abdomen — especially where preservation of rectus muscle is desired (preserves rectus for future use). - Pedicled propeller applications to close adjacent chest wall or epigastric defects; SEAP described for lower medial chest wall and xiphoid infections after sternal wounds. - Useful when pectoralis or rectus muscle flaps are unavailable or preservation of those muscles is preferred. - Size limits / bulk: - Vascular territory reliably extends vertically from costal margin to midpoint between xiphoid and umbilicus and laterally to anterior axillary line; contralateral capture is variable and unreliable — crossing midline should be done cautiously. - If larger volume or contralateral tissue required, consider bilateral SEAPs or alternate/adjunct flaps (e.g., DIEP). - Sensate reconstruction: - Sensory intercostal branches (10th–12th) may be dissected with perforator for sensate flap but rarely performed because it requires more intramuscular dissection. - Contraindications: - Absolute: absent or inadequate SEA perforator(s) at intended donor site (identified intraoperatively or on preop imaging), severe local infection that prevents flap survival in immediate period. - Relative: prior internal mammary artery harvest/ligation or obliteration (e.g., CABG) may compromise SEA inflow; extensive upper abdominal scars; prior thoracoabdominal operations that interrupt SEA or perforator course; large midline vertical defects where contralateral perfusion would be required (SEAP typically perfuses ipsilateral hemiabdomen only); poor patient medical status or unfit for surgery. - For SIEA vs SEAP decision logic: when superficial or alternative systems are dominant, consider SIEA or DIEP options; SIEA suitability is variable (present ~58% clinically; detected on CTA up to 94%; diameter range 0.3–3.1 mm; surgeons often seek ≥1.5 mm; suitability to support flap reported in ~24–31% of patients). ## Postoperative Care - Monitoring schedule/method: - Clinical monitoring (capillary refill, color, turgor, temperature, Doppler audible flow) at regular intervals in immediate postoperative period — treat as microsurgical transfer: frequent checks in first 24–48 hours. - Avoid overly tight dressings or abdominal binders that could compress pedicle; bandaging must not be too tight (explicit warning). - Use of implantable Doppler or handheld Doppler at surgeon’s discretion (not specifically mandated in chapters but standard microsurgical practice). - Warming: maintain normothermia; avoid local cooling of flap. - Antithrombotic practice: - No specific universal regimen stated in these chapters; follow institutional microsurgical protocols. (Do not invent specifics beyond the sources.) - Positioning/splinting: - Avoid positions that kink/compress pedicle; when closing donor site, place table in flexed position to reduce tension. For chest reconstructions, orient flap to avoid pedicle tension. - Drains: - Place drains at donor site (e.g., two Blake drains described for SIEA closure). Remove when output acceptable per unit protocol. - Mobilization, diet/analgesia: - Early ambulation as tolerated per standard postoperative care; analgesia per institutional practice. - Return-to-OR thresholds and time windows: - Any signs of flap compromise (sustained pallor, absent Doppler signal, progressive venous congestion, rapid deterioration in clinical parameters) warrant urgent re‑exploration — treat the SEAP like a microsurgical flap with prompt return to OR. Exact time windows not specified in these chapters; early re‑exploration recommended where compromise suspected. ## Complications (rates & management) - Reported numeric frequencies (from provided sources): - SIEA presence/detectability: present in ~58% of clinical dissections; detectable by CTA up to 94% (SIEA chapter). - SIEA diameter: 0.3–3.1 mm; suitability to support flap quoted in ~24–31% of patients; many surgeons seek ≥1.5 mm when harvesting. - SEAP perforator positional data: mean distances from midline/costal margin as above (Uemura). - DIEA/DIEP pedicle metrics for comparison: mean DIEA pedicle length average ~10.3 cm and average artery diameter ~3.6 mm (31.2 anatomy data). - Common complications (described and management principles present in the texts): - Inadequate arterial inflow or pedicle thrombosis: - Management: urgent exploration; confirm anastomosis; reposition pedicle free of kinks; consider additional arterial supercharging if anatomy allows (e.g., add an additional arterial anastomosis from another donor if documented insufficiency). - SEA/IMV absence (post CABG): recognize preoperatively; intraop, limit SEA dissection to avoid devascularizing perforator; if arterial inflow inadequate, convert to alternative flap source (e.g., DIEP) or add another pedicle. - Venous congestion: - Recognize early; management strategies described across abdominal flap chapters: explore urgently, identify venous outflow obstruction or thrombosis. Options include revision of venous anastomosis, adding an extra venous anastomosis (supercharging) using an available superficial vein (for abdominal flaps, the superficial inferior epigastric vein or other suitable veins are commonly used), or temporary exsanguination measures; where appropriate, consider conversion to alternate drainage routes. - For abdominal-based flaps, preserve/dissect superficial epigastric vein for 2–3 cm to use as additional venous conduit if needed (DIEP/SIEA pearls). - Partial flap necrosis / tip necrosis: - SEAP flaps: avoid extending vertical dimensions below midpoint xiphoid–umbilicus watershed; avoid excessive lateral extent beyond anterior axillary line; resect poorly perfused tip intraop or during early postop period; perform secondary procedures (debridement, grafting, local revision) or staged lipofilling if needed. - Donor-site morbidity: - Primary closure failure, wound dehiscence, hypertrophic scarring — donor closure technique and flexed-table closure recommended; use Scarpa’s sutures and drains to reduce seroma and tension. - Loss of rectus function: - SEAP harvest preserves rectus when intramuscular dissection is limited; preserve motor nerves where possible to avoid denervation. - Management algorithms (what, when, how): - Preemptive steps: - Preop imaging (CTA) to confirm perforator location and caliber. - Intraoperative confirmation: if perforator adequacy uncertain, identify alternative perforator or convert plan (e.g., DIEP, SIEA if anatomy favors). - Intraoperative testing: - Temporarily clamp adjacent perforators to test perfusion by chosen perforator when helpful (strategy described for SIEA ↔ DIEP decisions). - Leave a stump on main arterial branch if planning a bipedicled flap to permit additional anastomosis if required. - Postop salvage: - Early return to OR for suspected arterial or venous occlusion; explore pedicle, revise anastomosis, relieve kinks, add additional venous outflow (anastomose superficial vein to recipient), consider thrombolysis if indicated by institutional microsurgical protocols (specific drug/regimen not prescribed in these chapters). - If venous congestion localized and flap otherwise salvageable, adjunctive measures (medical leeching, local heparinization) not explicitly described in SEAP chapter — the text emphasizes surgical correction and additional anastomoses rather than nonsurgical temporizing measures. ## Key Clinical Pearls - Map perforators preoperatively with multidetector CT when available; mark perforator on skin and confirm with Doppler intraoperatively — SEAP perforators cluster in a trapezoid bounded by the costal margin and the midpoint between xiphoid and umbilicus. - Expect short pedicle length; plan flap orientation (axis parallel to costal margin) and inset to avoid pedicle kinking — harvest slightly more pedicle than immediately necessary to prevent torsion. - Avoid designing flap inferior to the horizontal midpoint between xiphoid and umbilicus (watershed zone) — vascular reliability there is poor. - Preserve motor nerve branches and limit intramuscular dissection to the perforator pathway to maintain rectus function. - If SEA/SEAP perfusion is questionable, intraoperative conversion to an alternative flap (e.g., DIEP) or harvest of an additional pedicle is preferable to risking a poorly perfused large flap. - For venous concerns: identify and preserve suitable superficial veins during inset (and dissect them for potential additional venous anastomosis); keep a short superficial vein length available (SIEV described as dissected 2–3 cm) to augment drainage if needed. - Primary donor‑site closure is strongly preferred; flex the table during closure to minimize tension and use layered Scarpa’s closure and drains to reduce seroma and wound complications. - When prior internal mammary harvest (CABG) is present, anticipate compromised SEA origin — evaluate preop and avoid extensive SEA dissection that could devascularize a chosen perforator; choose alternate donor/plan if needed.