**Region:** Chest and Shoulders # Scapular and Parascapular Flaps ## Anatomy - Pedicle: circumflex scapular artery (CSA) with venae comitantes. CSA is a terminal branch of the subscapular artery after the subscapular leaves the axillary artery (subscapular divides on average after 2.2 cm) and traverses the triangular (omotricipital) space to the lateral scapular border (Hanasono; Lee). Reported arterial caliber ranges in the source texts: approximately 1.8–4.5 mm to 2.5–3.5 mm (measured at variable levels); venous calibers reported 1.8–6 mm (Neligan; Watson; Mast/Nesmith). Pedicle length can be 4–6 cm when taken at the level of the cutaneous circumflex scapular artery, 7–10 cm to the subscapular level, and up to 11–14 cm (or more if subscapular/axillary dissection performed) — pedicle may be lengthened by including the subscapular or dissecting to the axilla (Lee; Neligan; Watson). - Course: CSA exits the triangular space (bounded superiorly by teres minor, inferiorly by teres major, laterally by long head of triceps), gives off infrascapular/muscular/periosteal branches, and then subdivides into terminal cutaneous branches: a transverse (scapular) branch, a descending (parascapular) branch, an ascending branch, and occasional anterior branches. The scapular cutaneous branch runs transversely; the parascapular (descending) branch runs inferiorly along the lateral border toward the scapular tip. The angular branch to the scapular tip commonly arises from the thoracodorsal system and supplies the scapular tip (Hanasono; Lee; Neligan). - Perforator pattern: a consistent direct septocutaneous perforator passes from the CSA through the deep dorsal thoracic fascia at the triangular space, arborizing suprafascially into transverse/descending/ascending branches. The circumflex scapular artery perforator (CSAP) is essentially a single, reliable perforator at this site and can support thin septocutaneous flaps (Neligan; Watson). - Nerves: cutaneous innervation of the dorsal thorax is via dorsal rami and segmental branches; no single dominant sensory nerve is present — scapular/parascapular flaps are generally insensate (Lee; Neligan). - Included tissues: skin, subcutaneous tissue, dorsal thoracic fascia; options to include latissimus dorsi or serratus anterior muscle slips, and scapular bone (lateral border or scapular tip) as osteocutaneous or myo-osteocutaneous components. Lateral border bone vascularized by periosteal branches from the CSA descending/osseous branch; scapular tip vascularized by the thoracodorsal angular branch if included (Hanasono; Neligan). - Thickness/profile & arc of rotation: back skin may be thin in lean patients and bulky in obese patients; CSAP and adipofascial/fascial variants allow thin flaps; pedicled reach includes axilla, shoulder, lateral chest, anterior chest and can be tunneled through the triangular space; as a free flap, used commonly for head & neck, upper/lower extremity, and complex reconstructions (Lee; Watson). - Common variants/anomalies (numbers from sources where reported): CSA may arise directly from axillary artery in ~4% (Mast/Nesmith; Neligan reports occasional origin variations and Lee cites infrequent <5% variations). The angular branch origin is variable (most commonly from the latissimus branch of thoracodorsal but variable distribution reported) (Hanasono). ## Dissection Steps 1. Positioning, markings, landmarks. - Position: lateral decubitus (preferred) or prone; ipsilateral arm abducted/prepped into field (≈90°) to expose axilla and allow anterior dissection if extra pedicle length needed (Lee; Mast/Nesmith). For combined procedures, table rotation strategies to avoid intraoperative repositioning are described (Hanasono). - Surface markings: palpate/mark posterior midline, scapular spine, scapular angle/tip, lateral border of scapula, posterior superior iliac spine and the triangular space. Triangular space location approximations: ~two-fifths of the distance from scapular spine to scapular tip along lateral border, or methods using two fingerbreadths above the inferior angle and two fingerbreadths below the spine to frame the flap (Urbaniak method) (Hanasono; Watson; Neligan). Confirm perforator/pedicle location with handheld Doppler preoperatively and mark the point where CSA exits the triangular space (Lee; Neligan). - Flap design: scapular (transverse) paddle centered over horizontal branch; parascapular (vertical/oblique) paddle centered over descending branch running along lateral border. Reported practical widths are limited by primary closure (commonly 5–7 cm recommended in some texts; other authors report up to 10–12–15 cm closed primarily depending on patient and technique) and lengths vary — parascapular designs up to 25–35 cm described in experienced hands (Hanasono; Lee; Watson). Use “pinch test” to confirm donor-site closability (Neligan). 2. Plane (suprafascial/subfascial), perforator identification (handheld/IO Doppler). - Initial dissection: begin distally (medial or inferior) and elevate in a suprafascial/areolar plane immediately superficial to muscular aponeurosis, progressing retrograde toward triangular space. Stay in thin areolar plane for bloodless dissection; once the pedicle is localized, transition to subfascial dissection around the pedicle (Lee; Watson). - Perforator identification: use handheld Doppler to localize the strongest signal at or near the triangular space. For CSAP flaps, precise Doppler marking is essential; when raising a CSAP thin flap, identify the individual perforator arborizing to the skin and preserve the septocutaneous path (Neligan; Watson). 3. Pedicle dissection: exposure, control, division; transfer/inset; perfusion checks. - Expose triangular space: separate/retract teres minor (superior) and teres major (inferior) and long head of triceps laterally; open the potential space and identify the superficial CSA and its branches. Use fine scissors, bipolar, ligaclips for muscular/periosteal branches; pack bleeding temporarily if needed to improve exposure rather than rush dissection (Watson). - Ligation strategy: divide infrascapular and small muscular/periosteal branches if not required for composite harvest. If additional pedicle length required, extend dissection to include subscapular vessels and, if necessary, up to axillary origin (requires ligation of thoracodorsal when extending to subscapular origin) (Lee; Hanasono; Watson). - Bone harvest specifics: for lateral scapular border bone, outline bone, divide teres minor/major fibers to periosteum, osteotomies should stop at least 1 cm from glenoid fossa to avoid joint entry and stop short of scapular tip unless intended; leave thin muscle fibers on ventral scapula to preserve periosteal blood supply (Hanasono; Neligan). Scapular tip (angular branch) identified by reflecting latissimus superiorly and tracing thoracodorsal/latissimus branches to the angular branch if scapular tip osteocutaneous harvest planned (Hanasono). - Division & transfer: island the flap on its pedicle and, for free transfer, divide pedicle with adequate length and perform microvascular anastomoses to recipient vessels. Perform immediate perfusion checks by clinical inspection and Doppler; for CSAP/thin flaps, confirm bleeding at flap edges and Doppler flow in pedicle before inset (Neligan; Lee). 4. Donor-site closure techniques. - Primary closure is preferred; design flap width to permit primary closure (pinch test). Smaller flaps (<8–10 cm) commonly closed primarily; larger defects may need skin graft or preoperative tissue expansion. Closed-suction drains are used to prevent seroma; repair any detached muscles to remaining scapula (drill holes for sutures if needed) (Lee; Hanasono; Neligan). Consider staged tissue expansion pre-transfer when a very long thin flap is required (Neligan). ## Indications and Contraindications - Indications: - Pedicled resurfacing of shoulder and axilla, axillary hidradenitis defects (Mast/Nesmith). - Free cutaneous/fasciocutaneous flap for large head & neck skin and soft-tissue defects; thin CSAP option for less bulky coverage (Lee; Neligan). - Osteocutaneous reconstructions: lateral border or scapular tip for mandibular, maxillary, palatal, calvarial defects when fibula is not suitable; scapular tip useful for palatoalveolar complex and hemimaxillectomy reconstructions (Hanasono; Neligan). - Chimeric reconstructions: composite combinations with latissimus dorsi, serratus anterior, and scapular bone on a single subscapular axis pedicle for complex 3D defects (Neligan; Hanasono). - Contraindications / relative limitations: - Prior ipsilateral axillary dissection, irradiation, or lymphedema — consider contralateral donor (Hanasono; Lee). - Patient habitus: morbid obesity produces excess bulk and may render triangular space hard to palpate; flap may be too bulky for certain reconstructions (Lee; Watson). - Anatomic variation when CSA arises directly from axillary may limit chimeric flap creation (~4% reported) (Mast/Nesmith; Neligan). - No reliable sensate option — not indicated when a sensate flap is essential (Lee; Neligan). ## Postoperative Care - Monitoring schedule/method: standard microvascular free-flap surveillance — clinical checks (color, turgor, capillary refill), handheld Doppler of pedicle; for pedicled flaps, avoid compression at triangular space and inspect perfusion. Specific implantable probes not detailed in the source texts (Lee; Neligan; Watson). - Warming/antithrombotic practice: general thromboembolic prophylaxis is recommended during the perioperative period (Watson). No specific anticoagulation protocols given in the cited material. - Positioning/splinting: avoid compression of triangular space; limit vertical/anterior elevation of the arm until donor-site healing adequate; keep limb support to prevent undue pressure on pedicle (Neligan; Watson). - Drains: closed suction drains at donor site advised; remove per routine when outputs acceptable (Hanasono; Lee). - Mobilization/ROM: begin range-of-motion exercises several days post-op; reported transient loss of shoulder abduction for up to 6 months has been described with eventual normalization by ~1 month to 6 months depending on series — repair detached muscles at closure and institute physiotherapy (Hanasono). - Diet/analgesia: standard postoperative care per institutional protocols; not specified in sources. - Return-to-OR thresholds and time windows: immediate re-exploration for suspected flap vascular compromise (clinical signs or loss of Doppler signal) is implied standard practice in microvascular surgery but specific time windows/algorithms are not enumerated in the provided texts. ## Complications (rates & management) - Vascular/anatomic variations: - CSA arising directly from axillary artery or duplicate/variant branches — infrequent (<5% variations reported) and may affect flap planning/combination flaps (Lee; Neligan). - Flap-specific complications: - Bulkiness/fatty flap in obese patients — can limit application; thin CSAP, adipofascial or fascial variants, or tissue expansion can mitigate (Neligan; Dabernig cited in texts). - Pedicle injury/bleeding: triangular space dissection can be bloody; if significant bleeding occurs, pack and improve exposure rather than frantic hemostasis to avoid pedicle damage (Watson). - Donor-site problems: conspicuous scar; seroma; shoulder weakness/stiffness after large bone/muscle harvest; risk of winged scapula with extensive muscle or rib harvest; risk of pneumothorax if rib/scapular tip harvest enters pleura (Neligan; Hanasono; Watson; Mast/Nesmith). - Frequencies: anatomic variation frequencies reported (<5% for several variations; ~4% for CSA arising independently from axillary artery) (Lee; Mast/Nesmith). - Management algorithms: - Hemorrhage in triangular space: pack with wet swab, obtain exposure and suction, then identify and ligate offending branch under good visualization (Watson). - Venous congestion/arterial thrombosis/complete flap loss: standard microvascular salvage principles (urgent re-exploration, revise anastomosis, relieve mechanical causes) are the accepted approach; specific protocols (leeching, thrombolysis) are not detailed in the provided texts. - Donor-site seroma/hematoma: closed suction drainage and evacuation if large; repair muscular attachments at closure to minimize functional deficits (Hanasono; Lee). ## Key Clinical Pearls - Mark the triangular space precisely — approximately two-fifths of the distance from the scapular spine to the scapular tip along the lateral border (or use the Urbaniak two-fingerbreadth method) and confirm with handheld Doppler to ensure the pedicle is captured within the skin paddle (Hanasono; Watson). - Begin flap elevation in a suprafascial/areolar plane and proceed retrograde toward the triangular space; once pedicle is localized, convert to subfascial dissection around the vessels to avoid inadvertent pedicle loss (Lee; Watson). - Preserve muscular and periosteal branches when planning osteotomies — leave at least 1 cm from the glenoid fossa when harvesting lateral scapular border bone and maintain thin subscapular muscle fibers on the ventral scapula to protect periosteal circulation (Hanasono; Neligan). - To lengthen pedicle: dissect proximally to include subscapular vessels or to the axillary origin; be prepared to ligate thoracodorsal vessels if extending to subscapular origin (Lee; Neligan). - Use CSAP when a thin pedicle-based flap is required — Doppler-mark the precise perforator at the triangular space and raise the flap in the superficial fascial/subdermal plane to minimize bulk (Neligan; Dabernig approach described). - When combining soft tissue and bone (chimeric design), exploit the common subscapular axis to inset multiple independent components (skin, muscle, scapular bone) with a single recipient microvascular anastomosis — plan vascular branching carefully pre-harvest (Neligan; Hanasono). - For donor-site closure, plan width by pinch test; consider pre-transfer tissue expansion for very long thin flaps or staged strategies to permit primary closure and reduce conspicuous scarring (Neligan). - If significant bleeding encountered in the triangular space during pedicle dissection, pack and obtain exposure rather than frantic coagulation; small muscular branches may be numerous and require methodical ligation/clips (Watson).