Forearm Fasciotomy - Volar and Dorsal (Complete Release)

Indication. Forearm compartment syndrome — a surgical emergency. The diagnosis is primarily clinical: pain out of proportion to the injury, a tense rock-hard forearm, and the single most sensitive test, pain on passive finger extension (which stretches the ischaemic volar flexors). Once the diagnosis is made clinically in a high-risk limb, decompress immediately — delay beyond 6 to 8 hours risks irreversible Volkmann's ischaemic contracture. High-risk injuries that demand a high index of suspicion: - Supracondylar humerus fractures — the leading paediatric upper-limb cause; overall incidence is low (under 1 percent) but rises sharply with vascular injury, the pink pulseless hand, or a median/AIN deficit.

• Both-bone forearm fractures — especially high-energy, displaced, or after manipulation.
• Crush injuries — direct forearm compression, prolonged extrication.
• Arterial injection injuries — intra-arterial drug injection causing chemical injury and swelling.
• Reperfusion after vascular repair — ischaemia of more than 4 to 6 hours followed by revascularisation.
• Burns — circumferential or deep burns with eschar constriction.

Pressure measurement is reserved for when the diagnosis is uncertain — the unconscious, obtunded, or uncooperative patient, or an equivocal exam. Insert the needle perpendicular to the fascia at the zone of maximal swelling and measure each of the four compartments. Normal resting pressure is 0 to 8 mmHg. Fasciotomy is indicated when the absolute pressure is greater than 30 mmHg, or the delta pressure (diastolic minus compartment) is less than 30 mmHg. In children, some use an absolute pressure greater than 20 mmHg or a delta less than 40 mmHg.

Document a neurovascular baseline before surgery — median nerve (APB opposition, sensation to thumb/index/middle), ulnar nerve (interossei/ADM, small/ring sensation), radial nerve (wrist/finger/thumb extension, first web sensation), AIN (FPL and index FDP — pinch, purely motor), and vascular status (radial and ulnar pulses, capillary refill, hand perfusion). This protects the patient and the medicolegal record. Consent for the open wounds, the high likelihood of a skin graft (60 to 80 percent), nerve injury, possible muscle loss and contracture, the second-look operation, and the prolonged rehabilitation. Setup. Supine, arm on a radiolucent arm board, shoulder abducted 80 to 90 degrees, forearm supinated for the volar approach (then pronated for the dorsal). Apply an upper-arm tourniquet but do not inflate it — you must be able to assess perfusion and bleeding. Prepare the entire limb shoulder to fingertips and drape to allow repositioning. Have vascular surgery available if an arterial injury is suspected.

The goal: completely decompress all four compartments through a volar curvilinear incision (superficial volar, deep volar, mobile wad, with extension into the carpal tunnel) and a dorsal longitudinal incision (mobile wad and extensor compartment), then leave every wound open. The exposure and the order of release are laid out step by step below — this is the heart of the operation.

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Immediate post-operative monitoring. Elevate the arm to heart level. Neurovascular checks every 2 hours for 24 hours, then every 4 hours — monitor radial and ulnar pulses, capillary refill, finger sensation and motion, and pain level, and palpate through the dressing for tension. Increasing pain or a tense forearm despite open wounds signals recurrent compartment syndrome: remove all dressings, re-examine, and return to theatre for revision if a compartment is still tense. Medical management when muscle necrosis is present — prevent the myonephropathic syndrome. Aggressive IV hydration (target urine output 1 to 2 ml/kg/hour), urine alkalinisation with sodium bicarbonate (urine pH greater than 6.5 prevents myoglobin precipitation in the tubules), and close monitoring of CK (often greater than 10,000 to 50,000 U/L), myoglobin, creatinine, potassium (hyperkalaemia) and calcium (hypocalcaemia). Dialysis is needed if acute renal failure develops — mortality is 5 to 10 percent once ARF occurs. Add skin-flora antibiotics (broad-spectrum if contaminated), DVT prophylaxis, and analgesia that does not mask a developing compartment syndrome. Second look at 48 to 72 hours is mandatory for every patient. Reassess muscle viability with the 4 Cs, debride frank necrosis, preserve any questionable muscle that shows viability, send tissue for culture if infection is suspected, and plan definitive wound closure. Radical debridement may require a further second look.

Rehabilitation. Phase 1 (weeks 0 to 2): splint wrist neutral, fingers free, wound care. Phase 2 (weeks 2 to 6): active range of motion, gentle stretching, oedema control, scar massage once healed. Phase 3 (weeks 6 to 12): progressive resistance and function. Phase 4 (months 3 to 6): work- and sport-specific activity, aggressive stretching to prevent contracture. Intensive hand therapy is critical — 3 to 6 sessions a week for 6 to 12 months. Expected outcomes. Full recovery in 40 to 60 percent if fasciotomy is performed within 6 hours; partial recovery (some stiffness or weakness) in 30 to 40 percent; poor outcome in 10 to 20 percent if delayed beyond 8 hours (established Volkmann's contracture). Predictors of a poor outcome are delayed fasciotomy, muscle necrosis requiring debridement, concomitant nerve injury, infection, and non-compliance with therapy.

Epidemiology. Forearm compartment syndrome is most often fracture-driven and male-predominant. In the largest dedicated forearm series (Duckworth, 2012), a fracture of the radius and/or ulna was the cause in 69 percent and isolated soft-tissue injury in 31 percent, with a marked male predominance (82 of 90 patients) and a mean age of 33. The median time from injury to fasciotomy was 12 hours, and a delay of more than 6 hours significantly increased complications. In children, forearm and supracondylar fractures are the dominant triggers (Grottkau, 2005 — 85 percent of 133 paediatric cases were fracture-related, and open fractures significantly raised the risk); a substantial proportion declare only after admission, mandating structured serial monitoring of the at-risk paediatric limb. The four-compartment anatomy is the operative map. The full reference anatomy:

Volkmann's ischaemic contracture — classification (Tsuge/Seddon). The late consequence of delayed or missed decompression: irreversible flexion contracture from muscle fibrosis after prolonged ischaemia. Mild — flexion contracture of 2 to 3 fingers (usually middle/ring), wrist flexion and intrinsics preserved. Moderate — all fingers flexed, wrist flexed, some intrinsic weakness and a sensory deficit. Severe — all muscle groups (flexors, extensors, intrinsics) fibrotic, a severe contracture with claw hand and sensory loss. Prevention — early fasciotomy within 6 to 8 hours — is the only effective treatment; outcome is poor once a contracture is established. Key evidence. Decompression within 6 hours minimises complications (Duckworth, 2012). When clinical assessment is unreliable, continuous differential (delta) pressure monitoring is highly accurate — McQueen (2013) reported estimated sensitivity 94 percent and specificity 98 percent, with only 5 false negatives and 6 false positives — but it supplements, never replaces, a clinical diagnosis. The delta-pressure rule itself was established by McQueen and Court-Brown (1996): an absolute pressure threshold (30 or 40 mmHg) would have led to many unnecessary fasciotomies, whereas a delta pressure (diastolic minus compartment) of less than 30 mmHg produced no missed cases. Ulmer (2002) showed that no single clinical sign is sensitive (13 to 19 percent) but that their absence is reassuring, and the probability of compartment syndrome rises to about 93 percent when three or more findings are present — so serial examination drives the diagnosis.