**Region:** Chest and Shoulders # Parascapular Cutaneous Axial Flap ## Anatomy - Pedicle: circumflex scapular artery (CSA) with venae comitantes draining to thoracodorsal vein in most cases. Reported arterial calibers: - CSA at origin: reported ranges 2.5–3.5 mm (Hanasono) and 1.8–4.5 mm (Watson/Neligan); the subscapular artery at its origin has been reported 4–8 mm. Pedicle length varies with proximal dissection: cutaneous CSA level ~4–6 cm; inclusion to subscapular level ~7–10 cm; dissection to axillary origin up to ~11–14 cm. - Mean venous calibers reported ~1.8–6 mm depending on level. - Course (origin → flap): - Subscapular artery arises from the axillary artery and after a short course (reported average 2.2 cm) divides into thoracodorsal and circumflex scapular branches. - Circumflex scapular artery traverses the triangular (omotricipital) space (bounded superiorly by teres minor, inferiorly by teres major, laterally by long head of triceps) and gives periosteal/muscular branches then becomes the superficial cutaneous hub that divides into terminal branches: - Transverse (horizontal) branch → scapular (transverse) flap axis. - Descending branch → parascapular (vertical) flap axis running parallel to the lateral border of the scapula. - Smaller ascending and anterior branches are described in some patients. - A consistent perforator exits at or immediately distal to the triangular space and arborizes suprafascially into the dorsal thoracic fascia/skin (the basis of the CSAP flap). This perforator is septocutaneous (passes through septum between teres major/minor), simplifying pedicle dissection. - Perforator pattern: single dominant septocutaneous perforator usually at triangular space, which then gives transverse, descending, (and sometimes ascending/anterior) cutaneous branches radiating outward. CSAP (circumflex scapular artery perforator) flap skin island reported up to ~14 × 7 cm when based on single perforator. - Choke vessels / adjacent angiosomes: cutaneous branches radiate in overlapping angiosomes over the dorsal thoracic fascia; safe harvest requires inclusion of the branch axis and capture of overlap when large or extended flaps are planned. - Nerves: dorsal rami and branches of cervical plexus provide cutaneous sensation to the back. There is no single dominant sensory nerve to reliably harvest a sensate parascapular flap; the flap is generally non‑sensate. - Included tissues: skin, subcutaneous tissue and dorsal thoracic fascia; may be taken as fasciocutaneous, adipofascial, fascial, myocutaneous (with latissimus/serratus slips), or osteocutaneous (lateral border or tip of scapula). Thickness profile: generally thin in non‑obese patients; can be bulky in obese patients. Arc of rotation (pedicled): reach to shoulder, axilla, lateral chest, anterior chest and, when mobilized through the triangular space, anterior axilla/upper arm/supraclavicular region; as free flap it can be inset to head & neck, extremities, trunk. Common variants/anomalies: - CSA occasionally originates directly from axillary artery (~4% reported). - Descending branch may travel deep to teres major in a minority of cases. - Angular branch to scapular tip arises variably from thoracodorsal system (reported origins: latissimus branch 51%, serratus branch 25%, trifurcation 20%, proximal thoracodorsal 4%). ## Dissection Steps 1. Positioning, markings, landmarks. - Position: lateral decubitus is preferred for exposure and ability to move the ipsilateral arm (arm abducted/prepped into field). Prone is an alternative for posterior defects. - Landmarks to mark preoperatively: posterior midline, scapular spine, scapular angle (inferior angle), lateral border of scapula, posterior superior iliac spine (for extended parascapular axis), and the triangular space (approximate location = ~two‑fifths of the distance from scapular spine to scapular tip along lateral border; Urbaniak “rule of twos” and Doppler confirmation recommended). - Flap design: - Scapular (transverse) axis parallels scapular spine; Urbaniak approximation: extend medially to within ~2 cm of midline, laterally to ~2 cm above posterior axillary fold, superior 2 cm below scapular spine, inferior 2 cm above scapular angle. Width typically limited by primary-closure ability (commonly 5–7 cm or up to ~10 cm; many centers report primary closure for flaps up to 8–12+ cm depending on laxity). - Parascapular (vertical) axis centered over lateral border; reported safe dimensions: width up to ~15 cm and length up to ~25 cm (some series report skin paddles as long as 30–35 cm in experienced hands). Place lateral/proximal end over triangular space. - Preop handheld Doppler used to mark superficial CSA/perforator at triangular space. 2. Plane, perforator identification. - Initial dissection: incise skin and elevate flap in a suprafascial (subcutaneous) plane, staying in loose areolar plane just superficial to the deep fascia/aponeruosis of infraspinatus/teres minor/teres major. - Distal → proximal (retrograde) dissection is commonly used: elevate skin island toward the triangular space, maintaining full thickness of subcutaneous tissue with flap until the vascular axis/pedicle is identified. - Alternatively, proximal → distal technique: identify pedicle at triangular space first (expedient when anatomy is clear), then delineate flap. - Use Doppler to guide pedicle location; in thin patients the vessel may be visible through areolar fascia. In bulky patients, bevel the incision and include a cuff of subcutaneous tissue to ensure capture of perforator; trim later when pedicle is mapped. 3. Pedicle dissection: exposure, control, division; transfer/inset; perfusion checks. - Open triangular/omotricipital space by separating teres minor (superior) and teres major (inferior) and retract long head of triceps laterally. Use self‑retaining retractors to open the space. - Identify superficial branch of CSA and its transverse/descending branches; divide small muscular and periosteal branches with clips or ties as encountered. - If additional pedicle length is required, continue dissection proximally to include the subscapular artery or to axillary origin; this often requires ligation of thoracodorsal branches if subscapular vessels are taken. - For CSAP (thin perforator) flaps, carefully dissect the perforator as it exits the triangular space to the subdermal plexus; raise flap in superficial fat plane to preserve thinness. - For osseous inclusion (lateral border scapula): outline bony segment with infraspinatus retracted laterally and teres minor/major divided to periosteum; score periosteum, perform osteotomies stopping ≥1 cm from glenoid fossa and short of scapular tip; preserve musculoperiosteal branches; mobilize bone with thin layer of subscapular muscle to preserve periosteal blood supply. - Once pedicle is freed to desired length and caliber, confirm flap perfusion (clinical assessment: color, capillary refill, bleeding edges; handheld Doppler on artery/vein). Divide pedicle and transfer as pedicled or free flap. - If pedicle dissection into axilla needed, consider a transverse axillary counterincision for safe exposure. 4. Donor-site closure techniques. - Primary closure if flap width compatible with pinch test; many centers report primary closure achievable for widths ≤8–12+ cm depending on laxity and location. For parascapular primary closure reported up to ~15 cm in some series. - Use layered closure, repair detached muscles (teres major, rhomboid) to scapula with sutures; drill holes in bone for reattachment if necessary. - Place closed suction drains. - Avoid skin grafting over back where possible (graft take is less reliable); if unavoidable, graft only after appropriate preparation. - Start gentle shoulder range‑of‑motion within several days; full normalization often reported by 1 month (range of movement deficits have been reported to persist up to ~6 months before recovery). ## Indications and Contraindications - Indications: - Large cutaneous and subcutaneous soft‑tissue defects of head & neck (scalp, facial, intraoral lining), trunk, and extremities. - Free flap for head & neck reconstruction (fasciocutaneous resurfacing; chimeric combinations with latissimus, serratus, scapular bone for composite defects including mandible/maxilla/calvarium). - Pedicled flap for axilla, shoulder, lateral chest, anterior chest via passage through triangular space. - Osteocutaneous reconstructions: lateral scapular border or scapular tip for mandibular/maxillary or palatal reconstruction (up to ~14 cm of bone harvest reported; lateral border thickness 0.7–1.2 cm; midportion thinner ~0.2 cm). - Thin coverage needs: CSAP thin perforator flap variant (smaller, thinner paddle). - Size limits (reported): - Parascapular paddles reported up to ~15 cm width × 25 cm length (some report paddles up to 30–35 cm length in experienced hands). - CSAP flaps (thin perforator) reported up to ~14 × 7 cm. - Bone harvest: lateral border length 10–14 cm; segment examples ~12 × 3 cm; up to 14 cm reported when preserving 1 cm from glenoid fossa. - Contraindications (relative/absolute derived from sources): - Prior ipsilateral axillary dissection or irradiation, or ipsilateral upper‑limb lymphoedema — consider contralateral donor site. - Active donor‑site infection or local soft‑tissue compromise. - Severe obesity when thin flap required — flap may be excessively bulky; thinning compromises vascularity and is generally avoided. - Situations requiring sensate flap — this flap is generally non‑sensate (no reliable dominant sensory nerve). ## Postoperative Care - Monitoring schedule/method: - Free‑flap microsurgical monitoring per institutional microvascular protocols (frequent clinical checks and Doppler as available). For pedicled flaps monitor for compression at triangular space. - Clinical assessment: color, turgor, capillary refill, bleeding from pinprick; handheld Doppler for arterial signal and venous flow when feasible. - Warming: maintain normothermia and avoid local compression/pressure at pedicle entrance. - Antithrombotic practice: routine perioperative thromboembolic prophylaxis is recommended; specific microvascular anticoagulation protocols vary by center (papers note thromboembolic prophylaxis should be used). - Positioning/splinting: avoid compression of triangular space; avoid undue elevation or traction on pedicle; immobilize limb/shoulder as per inset requirements; early gentle ROM begun within days; full function often recovers by 1 month although transient abduction weakness reported up to 6 months. - Drains: closed suction drains at donor site; remove per routine when output low. - Mobilization/diet/analgesia: standard postoperative care; early ambulation unless contraindicated by recipient site. - Return‑to‑OR thresholds and time windows: - Any clinical concern for arterial insufficiency or venous congestion: immediate return to OR for exploration is advised (standard microvascular principle reflected in sources). For pedicled flaps relieve compression/untwist pedicle if possible. ## Complications (rates & management) - Vascular/Flap loss: - The literature presented does not provide uniform pooled failure rates for parascapular flaps specifically. Management guidance in the sources emphasizes prompt recognition and immediate re‑exploration for suspected arterial or venous compromise. - Venous congestion / arterial thrombosis: - Management principle: urgent re‑exploration; evacuate hematoma, evaluate and revise anastomosis or pedicle, relieve mechanical compression or kinking. (Sources emphasize immediate surgical correction for microvascular transfers; conservative measures not specifically detailed in the texts provided.) - Partial/total loss, infection, fat necrosis: - Not quantified specifically in these chapters. Sources note flap reliability is high when pedicle anatomy is respected; infection and fat necrosis are recognized but not numerically reported in referenced chapters. - Donor‑site issues: - Seroma/hematoma: drains recommended to reduce seroma risk; repair muscle attachments to reduce dysfunction. - Contour deformity and conspicuous scar: donor scar on back can be noticeable; lateral oblique variants may be concealed in infra‑mammary fold in women; skin grafting yields less desirable aesthetic result and should be avoided when possible. - Shoulder dysfunction: transient loss of shoulder abduction reported up to ~6 months; repair of detached muscles and physiotherapy reduce long‑term morbidity. - Winged scapula/pneumothorax: risk increases with extensive bone or rib harvest; protect lateral scapular angle to minimize risk. - Anatomic variant frequencies: - CSA arising directly from axillary artery reported in ~4% of patients (parascapular chapter). - Angular branch origins: latissimus branch 51%, serratus 25%, trifurcation 20%, proximal thoracodorsal 4% (Hanasono). - Management algorithms (high‑level summary from texts): - Pedicled flap compression or kinking: immediately relieve compression, reposition dressings/limb; if perfusion not restored, convert to free transfer or take to OR. - Free flap vascular compromise: immediate re‑exploration; control hemorrhage/hematoma, inspect and revise anastomosis, remove kinks, consider extension of pedicle or change recipient vessels. Specific thrombolysis/medical regimens are not detailed in the provided chapters. ## Key Clinical Pearls - Mark the triangular space precisely (approx. two‑fifths the distance from scapular spine to scapular tip or by Urbaniak’s two‑fingerbreadth method) and confirm with Doppler — this is the hub of the pedicle; ensure lateral/proximal margin of flap overlies this point. - Dissect initial flap in a suprafascial plane distally → proximally until the pedicle is identified, then convert to subfascial dissection around pedicle; alternatively identify pedicle first (proximal → distal) when anatomy clearly palpable. - The CSA perforator is septocutaneous exiting between teres major and minor — open the triangular space with self‑retaining retractors and divide muscular/periosteal branches carefully; bipolar and fine scissors are useful. - To lengthen pedicle take it proximally to subscapular or axillary origins (up to ~14 cm total) — note this may require ligation of thoracodorsal branches. - Flap sizing/closure: use the pinch test. Donor primary closure commonly possible for widths up to ~8–12 cm depending on laxity; parascapular flaps up to ~15 cm width have been closed in series but anticipate scar and donor‑site contour. - Osseous harvest: when including lateral scapular border, osteotomies should end ≥1 cm from glenoid fossa and stop short of scapular tip to avoid joint violation; lateral border bone lengths reported up to ~12–14 cm; lateral border thickness suitable for alveolar reconstruction but thin cortical bone limits osseointegration. - In obese patients or when thin soft tissue is required consider CSAP (thin perforator) variant, adipofascial/fascial harvest, or preoperative tissue expansion rather than aggressive thinning which may compromise vascularity. - When planning combined/chimeric reconstructions exploit the common subscapular axis to include latissimus, serratus, scapular bone as independent paddles on one pedicle to simplify microsurgery (single set of anastomoses).