**Region:** Trunk and Lower Back # Rectus Abdominis Myocutaneous (TRAM and VRAM) Flap ## Anatomy - Pedicle: named artery (typical diameter/length if present), venae comitantes; course from origin to flap/skin paddle; perforator pattern (number, location, intramuscular vs septocutaneous), choke vessels/adjacent angiosomes. - Deep inferior epigastric artery (DIEA) — dominant inferior pedicle for free/inferriorly based flaps. Origin: from external iliac artery, typically about 1 cm above the inguinal ligament; pierces transversalis fascia to enter the rectus sheath inferior to the arcuate line and runs on the deep surface of rectus (Transverse TRAM free; Rectus Abdominis Muscle Flaps). Mean arterial caliber documented at about 1.5–2.5 mm; venae comitantes mean caliber about 2.0–3.0 mm; pedicle can be traced to give approximately 6–10 cm (6–10 cm or up to 7–12 cm when dissected to the external iliac) of length for microvascular use (Rectus Abdominis Muscle Flaps; Flaps A-to-Z). - Superior epigastric artery (SEA) — dominant pedicle for superiorly pedicled/tranverse pedicled TRAM (pTRAM). SEA arises from the internal mammary artery and enters rectus deep at the costal margin approximately 2–4 cm from midline; vessel caliber ~1.8 mm reported for superior epigastric in pedicled TRAM description (Pedicled TRAM). - Superficial inferior epigastric artery (SIEA) — superficial system; lies just deep to Scarpa’s fascia, often at two-thirds the distance from midline symphysis pubis to ASIS; if adequate caliber can be used to avoid fascial/muscle harvest (Transverse TRAM free). - Course and anastomoses: DIEA and SEA anastomose in the periumbilical area through choke vessels; intercostal vessels (7th–12th, with 8th most significant to superior system) provide minor segmental input and collateralization (VRAM; Pedicled TRAM). - Perforator pattern: perforators are concentrated in the periumbilical region; epigastric perforators supply skin via medial and lateral rows passing through rectus; generally two or three moderate-to-large perforators will supply a DIEP/TRAM flap reliably, though single large perforators may be sufficient in select cases (Transverse TRAM free; Rectus Abdominis Muscle Flaps). Medial-row perforators yield longer pedicles and may perfuse across midline better for zone IV coverage (Transverse TRAM free). - Angiosomes / Hartrampf zones: transverse abdominal skin subdivided into zones I–IV (zone I ipsilateral over rectus; zone II contralateral over rectus; zone III lateral ipsilateral; zone IV lateral contralateral) — perfusion decreases as zone number increases; zone IV is least reliable and is commonly discarded for safety (Transverse TRAM free; Pedicled TRAM). - Nerves: sensory and motor branches relevant to flap harvest and sensate reconstruction. - Motor and sensory supply from segmental intercostal nerves T7–T12. Motor branches enter rectus on posterior surface at midportion; sensory dermatomes: T7–T9 above umbilicus, T10 at umbilicus, T11–T12 and L1 below (Transverse TRAM free; VRAM; Rectus Abdominis Muscle Flaps). - Nerves are typically sacrificed during full muscle harvest; preserving the inferior-most larger nerve (near arcuate line) reduces denervation of remaining rectus (Transverse TRAM free). - Included tissues: skin, subcutaneous fat, anterior rectus sheath (variable cuff), rectus abdominis muscle (full, partial, or muscle-sparing), teninous intersections; thickness proportional to patient habitus (obese → bulky flaps; VRAM often bulky and may require thinning for reach) (VRAM; Transverse TRAM free). - Fascial-sparing techniques: small cuff of fascia left around perforators (DIEP/MS-TRAM), or a 2‑cm central fascia strip preserved or harvested depending on technique (Pedicled TRAM). - Arc of rotation: pedicled superior TRAM/VRAM reaches chest/sternum when based on SEA; inferiorly based VRAM (DIEA) reaches pelvic/perineal/sacral defects via transpelvic passage; pedicled TRAM passed through a subcutaneous tunnel to the mastectomy pocket (VRAM; Pedicled TRAM; Transverse TRAM free). - Common variants/anomalies: - Free TRAM, pedicled TRAM (pTRAM), MS-TRAM, DIEP, SIEA, VRAM (superior or inferior based), double/bipedicle TRAM, midabdominal TRAM, delayed TRAM, fascial-sparing harvests (Transverse TRAM free; Pedicled TRAM; VRAM). ## Dissection Steps 1. Positioning, markings, landmarks. - Position: supine; waist at table bend so patient can be flexed/sitting for inset and to assist donor closure; arms out or tucked per preference (Transverse TRAM free; Pedicled TRAM). - Key landmarks: midline, linea semilunaris, arcuate line (semicircular line halfway between umbilicus and symphysis pubis), costal margin, pubis, ASIS (Transverse TRAM free; Rectus Abdominis Muscle Flaps). - Skin markings — transverse TRAM: lower-abdominal transverse ellipse; superior incision usually at/just above umbilicus; inferior incision just above pubis; flap tapered laterally; flap height at midline approximates desired breast base width (Transverse TRAM free). Pedicled TRAM: upper incision ≈2 cm above umbilicus to capture periumbilical perforators; lower incision planned to permit closure when flexed (Pedicled TRAM). VRAM: vertical midline marking over linea alba with lateral convex marking to capture perforator zone (VRAM). 2. Plane (suprafascial/subfascial), perforator identification (handheld/IO Doppler). - Initial plane: raise skin and subcuticular flaps in plane superficial to anterior rectus sheath until approaching linea semilunaris/perforator zone where dissection slows and perforators are encountered (Transverse TRAM free; Pedicled TRAM). - Perforator identification: identify SIEV and SIEA early (free TRAM technique) and dissect laterally-to-medially to visualize medial and lateral-row perforators in the periumbilical zone. Preserve large perforators; a DIEP chosen when a single large perforator or grouped perforators in one intramuscular septum are present. If perforators lie in different intramuscular planes, include a small cuff of muscle (MS-TRAM) (Transverse TRAM free). - Fascial handling: open anterior rectus sheath with minimal cuff of fascia around perforators for DIEP; mark/harvest a 2-cm strip of fascia for some pedicled TRAM techniques (Pedicled TRAM; Transverse TRAM free). 3. Pedicle dissection: exposure, control, division; transfer/inset; perfusion checks. - DIEA exposure (free/muscle-tracing): reflect/part the rectus muscle to expose deep aspect and follow DIEA proximally toward external iliac to gain pedicle length; ligate superior epigastric vessels when harvesting inferior DIEA-based free flap; leave pedicle intact until recipient site prepared (Transverse TRAM free; Rectus Abdominis Muscle Flaps). - Superior-pedicled TRAM/VRAM: dissect rectus muscle to costal margin to visualize superior pedicle; protect intercostal vessels that may contribute (Pedicled TRAM; VRAM). - Pedicled TRAM transfer: create subcutaneous tunnel (≈four fingerbreadths wide) and pass flap through, rotate 180° (ipsilateral flap clockwise / contralateral counterclockwise per laterality), inspect pedicle for kinking; mobilize lateral rectus fascia or release fibers as needed to relieve tension on pedicle (Pedicled TRAM). - Free flap inset: orient skin paddle (commonly vertical inset for breast with zones I/II inferomedial); DIEP/DIEA-based free TRAM from contralateral abdomen often rotated ~90° counterclockwise to orient pedicle medially toward internal mammary recipient vessels (Transverse TRAM free). - Perfusion checks and adjustments: preserve SIEV long for potential venous augmentation; discard zone IV in most cases; trim ischemic corners of zone III as needed; in marginal cases consider additional perforators or supercharging (Transverse TRAM free; Pedicled TRAM). 4. Donor-site closure techniques. - Fascial closure: primary closure if fascia-sparing; if tension or large fascial defect, use mesh reinforcement. Direction of mesh stretch placed to counter expected bulge (Pedicled TRAM: inlay Prolene mesh oriented superoinferiorly; VRAM: synthetic mesh above arcuate line, biologic mesh considered below arcuate line) (Pedicled TRAM; VRAM). - Quilting sutures of abdominal flap to musculature; closed-suction drains placed above fascial closure and in breast pockets (Transverse TRAM free; Pedicled TRAM; VRAM). - Umbilicus: reinsert through a midline opening; various inset techniques (e.g., upside-down U) described (Transverse TRAM free). ## Indications and Contraindications - Indications: - Breast reconstruction (free TRAM/DIEP/MS-TRAM/SIEA; pedicled TRAM common) — when sufficient abdominal tissue exists (Transverse TRAM free; Pedicled TRAM). - Chest wall/sternal reconstruction (superiorly based VRAM/TRAM) (VRAM). - Pelvic, perineal, vaginal reconstruction after extirpation; VRAM inferiorly based for pelvic dead-space obliteration and vaginal resurfacing (VRAM). - Large-volume soft-tissue coverage / free-tissue transfer for head and neck, extremity, and oncologic defects (Rectus Abdominis Muscle Flaps; VRAM). - For pedicled TRAM: optimal in nonsmokers with mild/moderate abdominal tissue requiring <1,000 g tissue; a unipedicled TRAM reliably provides about 50% of lower abdominal tissue (Pedicled TRAM). - Size limits / thin vs bulky: - Use DIEP or SIEA when a thinner skin paddle with preservation of muscle/fascia is desired. VRAM provides bulky soft tissue for dead-space obliteration and may require thinning in obese/Android pelvis patients (Transverse TRAM free; VRAM). - Sensate needs: - Preservation of neurovascular bundles or selective nerve coaptation may be planned for functional or sensate reconstructions; however, most motor/sensory intercostal nerves are sacrificed in standard harvest (Transverse TRAM free; Rectus Abdominis Muscle Flaps). - Contraindications: - Absolute/relative: prior ipsilateral subcostal incision (contraindicates ipsilateral superiorly based TRAM), prior harvest of internal mammary artery (relative contraindication to superiorly based flap), prior external iliac vessel surgery affecting DIEA origin without confirmed patency, inadequate abdominal tissue, patient unwilling to accept donor morbidity or prolonged surgery, significant hypercoagulable state (Transverse TRAM free; Pedicled TRAM; Rectus Abdominis Muscle Flaps). - Smoking, obesity, prior chest radiation increase risk and may prompt variation (delay, double-pedicle) or select alternative flap (Pedicled TRAM; Transverse TRAM free). ## Postoperative Care - Monitoring schedule/method: - Frequent early clinical checks (color, turgor, capillary refill), use of Doppler signals and preservation of accessible venous outflow options (SIEV preserved/clipped long when anticipated) (Transverse TRAM free; Pedicled TRAM). - Drains: closed-suction drains above fascia and in breast pockets; Blake drains commonly used (Pedicled TRAM; Transverse TRAM free). - Warming, antithrombotic practice: - Maintain normothermia; no specific anticoagulation regimen mandated in source chapters — assess and treat hypercoagulable risks preoperatively (Transverse TRAM free). - Positioning/splinting: - Early precautions to avoid tension on pedicle; when mesh used, flex hips intraoperatively to facilitate closure; postoperative activity advanced per institutional protocols (Pedicled TRAM; VRAM). - Drains, mobilization, diet/analgesia: - Standard use of drains; early ambulation as tolerated; multimodal analgesia; specifics not prescriptively provided in source texts (Pedicled TRAM; Transverse TRAM free). - Return-to-OR thresholds and time windows: - Any persistent or worsening vascular alarm (loss of Doppler signal, progressive pallor/cyanosis, hardening) warrants urgent re-exploration; early re-exploration is the accepted salvage strategy in the texts (Transverse TRAM free; Pedicled TRAM). No fixed hour window prescribed in sources — act promptly based on clinical findings. ## Complications (rates & management) - Vascular complications: - Venous congestion: common initially in pedicled flaps and often resolves within 24 hours; if persistent consider exploration, chemical leeching, venous cannulation or supercharging (Pedicled TRAM). - Chemical leeching: de-epithelialize small area and apply heparin to encourage bleeding until arterial/venous equilibration (Pedicled TRAM hints). - Cannulation of a large flap vein: exteriorize tied-off DIEV with angiocath to allow controlled bleeding (Pedicled TRAM hints). - Arterial thrombosis / arterial insufficiency: urgent re-exploration and revision of anastomosis (for free flaps) or conversion/supercharging for pedicled flaps; strategies and thrombolysis discussed as general salvage options in flap literature but specific protocols not detailed in the provided chapters (Transverse TRAM free; Pedicled TRAM). - Partial/total flap loss and fat necrosis: - Fat necrosis: reported rates variable; one series quoted pedicled TRAM up to 58.5% vs 17.7% for DIEP in one study; clinically detectable fat necrosis reported ~13.4% in some pedicled TRAM series vs 8.2% in free TRAM series. Zone II/IV more susceptible; medial-row perforators favor better perfusion to contralateral tissue (Pedicled TRAM; Transverse TRAM free). - Partial flap loss more common with pedicled TRAM vs free TRAM; total flap loss rare with pedicled TRAM (Pedicled TRAM). - Infection, seroma, hematoma: - Standard wound care and drains mitigate seroma/hematoma; rates not uniformly quantified across chapters. - Donor-site issues: - Hernia/bulge: widely variable reported incidence — some series report <1% with mesh closure, others report much higher rates (up to 44%) depending on technique, patient factors, and reporting definitions. Upper/lower abdominal bulge reported around 13% in some data sets; obesity and smoking are risk factors (Pedicled TRAM). - Functional impact: sit-up ability reported in series — 62% of single-pedicled TRAM patients and 27% of double-pedicled TRAM patients could perform sit-ups postoperatively; many patients report minimal interference with daily activities; objective testing shows return toward baseline by 1 year (Pedicled TRAM; Clinical studies summarized). - Management algorithms: - Re-exploration: immediate exploration for suspected pedicle thrombosis or unresolving congestion; revascularize or revise anastomoses (free flaps) or consider microvascular supercharging using preserved DIEA/V to recipient chest vessels as salvage (Pedicled TRAM; Transverse TRAM free). - Leeching/chemical leeching: de-epithelialize area and apply topical heparin to encourage oozing for venous decompression (Pedicled TRAM hints). - Venous cannulation: exteriorize deep inferior epigastric venous stump via angiocath for controlled drainage (Pedicled TRAM hints). - Mesh reinforcement: use synthetic mesh above arcuate line; biologic mesh preferred when placed in contact with abdominal contents below arcuate line (VRAM; Pedicled TRAM). ## Key Clinical Pearls - The arcuate line lies roughly halfway between umbilicus and symphysis pubis; below it the posterior sheath is deficient — take care with inferior dissection and closure (Transverse TRAM free). - Preserve and tag the SIEV/SIEA early (SIEV clipped long if not used) — reserve as an option for additional venous drainage or conversion to SIEA-based flap (Transverse TRAM free). - Include as many good-quality perforators as needed — commonly 2–3 moderate-to-large perforators will supply a DIEP; a single large perforator may suffice for a DIEP in select cases (Transverse TRAM free). - Medial-row perforators often provide superior cross-midline perfusion (better coverage of zone IV) and yield longer pedicle length — favor medial-row harvest when planning contralateral tissue transfer (Transverse TRAM free; Pedicled TRAM). - When performing pedicled TRAM harvest leave/preserve a 2‑cm central fascia strip or a small cuff of fascia around perforators to facilitate closure and reduce bulge risk; close with mesh if tension exists (Pedicled TRAM; VRAM). - Anticipate and plan for venous congestion in pedicled cases — have options ready: chemical leeching, venous cannulation of DIEV, or conversion to supercharged flap using preserved DIEA/V (Pedicled TRAM). - Dissect DIEA pedicle to external iliac when extra length and larger caliber are needed for free transfer — pedicle length of approximately 6–10 cm can usually be achieved (Rectus Abdominis Muscle Flaps). - In VRAM and pelvic reconstruction, perform fascial-sparing harvest where possible and be prepared to use unilateral component separation or mesh if prior surgery prevents fascial-sparing to reduce donor-site morbidity (VRAM). (Inline chapter hints: Transverse Rectus Abdominis Myocutaneous Free Flap; Transverse Rectus Abdominis Myocutaneous Pedicled Flap; Vertical Rectus Abdominis Myocutaneous Flap Free/Pedicled Flap; Rectus Abdominis Muscle Flaps; Pedicled Transverse Rectus Abdominis Myocutaneous Flaps.)