**Region:** Chest and Shoulders # Circumflex Scapular Artery Flap ## Anatomy - Pedicle: circumflex scapular artery (CSA), with two venae comitantes draining to thoracodorsal system. Reported arterial diameter ranges in the literature: 2.5–3.5 mm (handbook), 1.8–4.5 mm (text), and up to 2–6 mm at origin (anatomic series). Pedicle length varies with level of dissection: - CSA (cutaneous level): ~4–6 cm; - Subscapular-level dissection: ~7–10 cm; - Axillary (include subscapular/axillary origin): ~11–14 cm (can be lengthened to “up to 14 cm” when subscapular vessels are included). (Numbers reported in the attached sources.) Course: the CSA arises from the subscapular artery (subscapular originates from axillary; subscapular divides after an average course of ~2.2 cm), courses posteriorly toward the lateral border of the scapula, traverses the triangular (omotricipital) space (bounded superiorly by teres minor, inferiorly by teres major, laterally by long head of triceps), then gives an infrascapular (muscular/osseous) branch and a superficial branch that divides into transverse (scapular), descending (parascapular), and occasionally ascending or anterior branches. The superficial branch pierces the dorsal thoracic fascia at the triangular space and arborizes suprafascially. - Perforator pattern: a consistent solitary septocutaneous perforator exits the triangular space and radiates (spoke-like) into the dorsal thoracic fascia. This direct perforator is the basis of: - Transverse/scapular branch (scapular flap), - Descending/parascapular branch (parascapular flap), - Ascending and anterior variants when present. The perforator is described as present nearly 100% of the time; anatomical variations of branch origin or course are infrequent (<5% reported in some series). - Nerves: no single dominant cutaneous nerve supplies the whole territory; dorsal rami supply cutaneous sensation of the back. The CSA-based skin flaps are generally not sensate. Motor nerves relevant to harvest include thoracodorsal nerve (to latissimus) and the nearby long thoracic and lateral thoracic neurovascular structures in the axilla — avoid injury during proximal pedicle dissection and when harvesting osseous components. - Included tissues: skin and subcutaneous tissue (scapular/parascapular fasciocutaneous), deep fascia/adipofascial/fascial variants, optional latissimus/serratus muscle slips, and scapular bone (lateral border or tip). Bone metrics: lateral scapular border harvestable length reported up to ~12–14 cm (one series: up to 14 cm with preservation of 1 cm from glenoid fossa); lateral border thickness ~0.7–1.2 cm; mid‑scapula thin (~0.2 cm) — useful for palatal/orbital floor reconstruction. A scapular tip (inferior angle) can be based on the angular branch of thoracodorsal artery (different source) when required. - Thickness/arc of rotation/variants: flap thickness ranges from bulky (scapular/parascapular) to thin (circumflex scapular artery perforator, CSAP). CSAP can be elevated as a thin septocutaneous perforator flap or as adipofascial/fascial flap; chimeric configurations with latissimus, serratus, and vascularized scapula are standard. Pedicled arc reaches shoulder, axilla, lateral chest, anterior chest and supraclavicular area; as free flap, CSAP has adequate caliber for most recipient vessels. ## Dissection Steps 1. Positioning, markings, landmarks. - Position: lateral decubitus or lateral/oblique on suction bean bag. Some authors rotate table intraoperatively; ipsilateral arm prepped and available for abduction/flexion. (Lateral decubitus commonly preferred.) - Landmarks: - Palpate scapular spine, inferior angle, lateral border; mark triangular space located approximately two‑fifths of the distance from the scapular spine to the inferior (tip) angle along the lateral border (Urbaniak “rule of twos” and other described formulas). - Use a handheld Doppler to identify the superficial CSA/perforator at or near the triangular space and to trace the transverse/descending branch axis. - Scapular (transverse) flap axis: parallel to scapular spine; typical safe vertical limits ~2 cm below scapular spine, 2 cm above scapular angle, 2 cm lateral to midline (Urbaniak guidelines). - Parascapular (vertical) flap axis: runs from triangular space along lateral scapular border toward posterior superior iliac spine; design dimensions reported up to 15 cm width × 25 cm length (some series report parascapular length up to 30–35 cm). 2. Plane (suprafascial/subfascial), perforator identification (handheld/IO Doppler). - Elevation begins distally in a suprafascial plane (areolar plane just superficial to deep fascia) and proceeds retrograde toward the triangular space. Keep full thickness of subcutaneous fat in standard harvest unless deliberate thinning is planned. - For speed and safety some surgeons identify the pedicle first in the triangular space (proximal→distal) and then tailor the skin island. - Use handheld Doppler preoperatively and intraoperatively to confirm perforator; in obese patients Doppler and meticulous dissection are particularly important. 3. Pedicle dissection: exposure, control, division; transfer/inset; perfusion checks. - Open and enlarge the triangular space by retracting teres minor superiorly and teres major inferiorly; divide muscular and periosteal branches encountered; identify and clip infrascapular and muscular branches. - If more pedicle length or caliber is required, dissect proximally to include subscapular artery or even its axillary origin — this requires ligation of the thoracodorsal vessels if the subscapular is to be followed to axillary origin. - For CSAP flap: identify the septocutaneous perforator as it exits the triangular space; elevate thin flap in subdermal/subfascial plane just deep to subdermal fat. - For osseous harvest (lateral border): outline bone, divide teres minor/major and infraspinatus attachments to periosteum, score periosteum, perform osteotomy leaving at least 1 cm from the glenoid fossa and stopping short of the scapular tip where indicated; protect musculoperiosteal branches; preserve periosteal fibers on ventral scapular surface. - Transfer and inset: standard microvascular technique for free transfer; CSAP can be used as flow‑through flap (superficial CSA → transverse/descending branches) or combined as chimeric flap with latissimus/serratus/scapula. - Perfusion checks: clinical assessment and Doppler during harvest and after inset; intraoperative visual and bleeding checks at edges. (No fixed perfusion-test protocol specified in the sources.) 4. Donor-site closure techniques. - Primary closure is preferred where feasible. Typical safe donor‑site widths: - Flaps ≤8–9 cm may be closed primarily (some series report primary closure possible up to ~10–12–15 cm depending on patient habitus and tissue laxity). - Use closed suction drains. Reattach detached muscles (teres major/minor, rhomboid) to the scapula; drill holes through scapular bone if necessary to secure sutures. Avoid skin grafting when possible (poor graft take over the back reported); consider tissue expansion preoperatively when large surface area is needed. ## Indications and Contraindications - Indications: - Fasciocutaneous reconstruction for head and neck soft‑tissue defects (scalp, midface, intraoral lining), axillary/shoulder resurfacing, and extremity coverage. - Osteocutaneous scapular flap for mandible or maxilla reconstruction when fibula not suitable; scapular tip uniquely suited for palatoalveolar reconstruction. - Chimeric reconstructions (combine scapular/parascapular skin paddles, latissimus, serratus, and vascularized scapula) for complex 3‑D defects. - Pedicled flap options for axilla, chest, shoulder and lateral trunk; CSAP for thin coverage and flow‑through applications. - Size/character considerations: - Use scapular/parascapular when thin to moderate thickness needed; CSAP for thin septocutaneous requirement; bone up to 12–14 cm lateral border available (lengths reported). - Contraindications / relative limitations: - Prior ipsilateral axillary dissection, prior axillary irradiation, or upper‑limb lymphoedema — contralateral donor recommended. - Morbid obesity: flap may be excessively bulky; thinning compromises vascularity and is used cautiously. - When supine harvesting is required (supine position awkward for harvest). - Anatomic variation (rare) of CSA origin directly from axillary artery (reported ~4% in some series) may complicate chimeric harvest. ## Postoperative Care - Monitoring schedule/method: - Standard microvascular flap monitoring: frequent clinical checks and handheld Doppler for arterial/venous signals (specific schedules not prescribed in the source texts; follow institutional microvascular protocols). - For pedicled flaps: ensure no compression of triangular space; avoid tight dressings or positions that kink the pedicle. - Warming/antithrombotic practice: - Sources recommend routine microvascular precautions; no specific anticoagulant regimen is prescribed in these texts — apply institutional thromboembolic prophylaxis and microvascular antithrombotic protocols. - Positioning/splinting: - Avoid vertical/anterior elevation of the ipsilateral arm until donor site healing allows (to prevent pedicle tension/compression). - Begin range‑of‑motion exercises within several days; shoulder ROM may be reduced for up to ~6 months with expected normalization by ~1 month in many series (loss of abduction has been reported up to 6 months). - Drains, mobilization, diet/analgesia: - Closed suction drains at donor site; remove per routine. Early mobilization per standard microvascular and orthopedic guidance. Analgesia and nutrition as per usual postoperative care. - Return-to‑OR thresholds and time windows: - The source texts do not give explicit numeric thresholds or time windows for return to OR; they endorse standard urgent re‑exploration for suspected progressive arterial or venous compromise as per general microvascular practice. ## Complications (rates & management) - Anatomic/harvest variations and frequencies (reported): - CSA perforator found nearly 100% of the time; anatomic variations (e.g., descending branch course deep to teres major, CSA origin directly from axillary) reported infrequently (<5% in some series; origin from axillary artery ~4% in another series). - Flap loss/failure: - The attached sources do not provide pooled numeric rates for partial/total flap loss or thrombosis; they emphasize the pedicle’s reliability and applicable microvascular monitoring/management principles without quantified failure rates. - Donor‑site issues: - Temporary decreased shoulder abduction reported (up to 6 months in some series; commonly resolves). - Scarring of dorsal donor site can be conspicuous; large donor defects may require skin grafting (skin graft take over scapula can be suboptimal). - Bone harvest increases risk of shoulder weakness/stiffness; repair of detached musculature and physiotherapy are important. Pneumothorax is a recognized risk when ribs or extensive scapular bone are harvested. - Management algorithms: - The sources recommend standard microvascular management for compromised free flaps (urgent re‑exploration for progressive ischemia/venous congestion). Specific algorithms (leeching, thrombolysis dosing, exact re‑exploration time windows) are not detailed in the provided texts — apply established institutional microvascular salvage protocols. - Venous congestion / arterial thrombosis: - No specific incidence percentages provided in the sources; treat per general microvascular principles: immediate assessment, return to OR for exploration and revision of anastomosis when indicated. ## Key Clinical Pearls - Triangular space landmark: the CSA perforator emerges through the triangular (omotricipital) space, located approximately two‑fifths of the distance from scapular spine to inferior angle along the lateral border — center flap design over this point and confirm with Doppler. - Pedicle handling: if extra length is required, extend dissection proximally to the subscapular/axillary origin (can add ~5–8 cm), but this may require ligation of thoracodorsal branches and careful protection of axillary neurovascular structures. - Safe bone harvest: leave at least 1 cm of scapula from the glenoid fossa; lateral border bone harvest lengths reported up to ~12–14 cm; lateral border thickness ~0.7–1.2 cm (mid‑scapula ~0.2 cm) — plan orientation of cortical surface depending on implant/denture needs. - Flap size and closure: - Design widths so donor site closes primarily: commonly ≤8–10 cm reliably; some series report primary closure up to ~12–15 cm based on patient habitus. Parascapular flaps can be very long (reports of 25–35 cm); plan donor closure and consider tissue expansion if very large surface area needed. - Plane of dissection: elevate distally in the suprafascial/areolar plane and convert to subfascial/closer dissection approaching the triangular space. Alternatively, identify pedicle first proximally then proceed distally for faster, reliable harvest. - Preserve anastomotic branches when planning composite/chimeric flaps: maintain branches in teres major area when osteotomies or large muscle cuffs are planned; reattach divided muscles to scapula during closure (drill holes if needed). - Thin flap and CSAP use: for thin coverage, use the CSAP (septocutaneous perforator) or consider adipofascial/fascial variants or preoperative expansion rather than aggressive intraoperative thinning which risks vascularity. - Donor‑site management: avoid skin grafting the back when possible (poor take); use closed drains, repair detached muscles, and institute early physiotherapy — shoulder ROM generally recovers (some transient abduction loss reported up to 6 months).