What are the indications, surgical technique, and postoperative management for a lower‑leg fasciotomy in acute compartment syndrome?

Lower Leg Fasciotomy for Acute Compartment Syndrome

Indications for Fasciotomy

Perform immediate two-incision, four-compartment fasciotomy when compartment pressure ≥30 mmHg or when differential pressure (diastolic blood pressure minus compartment pressure) ≤30 mmHg, as these thresholds represent the most widely accepted cut-offs for operative intervention. 1, 2

Clinical Indications (Without Pressure Measurement)

• Pain out of proportion to injury combined with pain on passive stretch of the affected muscle compartment warrants immediate fasciotomy without delay for pressure measurement 1, 2
• When pain, pain on passive stretch, and paralysis are all present together, the positive predictive value reaches 93% for compartment syndrome, though paralysis indicates irreversible muscle ischemia may have already occurred 1
• Remove all constricting dressings, casts, or splints immediately and arrange urgent surgical consultation when compartment syndrome is suspected 1

Pressure-Based Indications (When Clinical Diagnosis Uncertain)

• Measure compartment pressures only if diagnosis remains in doubt, particularly in obtunded, sedated, or uncooperative patients who cannot reliably report pain 1, 2
• Hypotensive patients: fasciotomy at pressures ≥20 mmHg 1
• Unconscious or uncooperative patients: fasciotomy at pressures ≥30 mmHg 1
• Normotensive patients with positive clinical findings: fasciotomy at pressures ≥30 mmHg when duration of elevated pressure is unknown or exceeds 8 hours 1

Prophylactic Fasciotomy Indications

• Acute limb ischemia with prolonged or severe tissue ischemia (>4-6 hours) undergoing revascularization requires prophylactic fasciotomy to prevent reperfusion-induced compartment syndrome 3, 1, 2
• Category IIb acute limb ischemia with time to revascularization >4 hours warrants prophylactic fasciotomy 3
• High-energy trauma with tibial fractures, crush injuries, or vascular injuries are indications for early fasciotomy 2

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Surgical Technique

The two-incision, four-compartment fasciotomy is the gold standard technique that decompresses all leg compartments through lateral and medial incisions. 2

Standard Two-Incision Approach

• The lateral incision releases the anterior and lateral compartments 2
• The medial incision releases the superficial and deep posterior compartments 2
• This technique was used in 77% of cases in a large vascular surgery series and remains the standard approach 4
• The anterior compartment requires release in virtually all patients (100% in one series) 5

Alternative Selective Fasciotomy

• Selective fasciotomy (opening only compartments with measured pressure >30 mmHg) is feasible and appears safe in trauma patients when pressure measurement is performed 5
• In 67% of selective fasciotomy cases, release of only 2 compartments was sufficient 5
• However, this approach requires intraoperative pressure measurement and should only be considered by experienced surgeons in specific trauma scenarios 5
• Standard four-compartment fasciotomy remains the safest approach when any diagnostic uncertainty exists 2

Critical Technical Points

• Leave fasciotomy wounds open initially; never attempt primary closure at the index operation 2, 6
• Ensure complete fascial release along the entire length of each compartment to prevent residual elevated pressure 2
• Inspect muscle viability after decompression; necrotic muscle should be debrided 6

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Postoperative Management

Immediate Post-Fasciotomy Care

Position the limb at heart level (not elevated) to optimize perfusion pressure while avoiding excessive elevation that worsens ischemia. 1

• Monitor for myoglobinuria and maintain urine output >2 ml/kg/h to prevent acute kidney injury from rhabdomyolysis 1, 2
• Administer sodium bicarbonate to alkalinize urine, as myoglobin is less likely to precipitate in alkaline urine 1
• Regular clinical assessment of limbs for swelling, muscle softness, and peripheral pulses or oxygen saturation 1
• Measure compartmental pressures if any suspicion of recurrent or residual compartment syndrome exists 1

Wound Closure Strategy

Plan for delayed closure at a median of 5 days; early delayed primary closure can be attempted if minimal tissue bulge occurs or resolves with systemic diuresis and leg elevation. 2

• Delayed primary closure is the preferred method when tissue edema resolves sufficiently, typically within 3-7 days 2, 6
• Negative pressure wound therapy (NPWT/VAC) facilitates wound closure or prepares the wound bed for skin grafting when primary closure is not feasible 2, 6
• Skin grafting is required when wounds cannot be closed primarily, typically after 7-14 days 4, 6
• Fasciotomies were successfully closed in 69% of patients at an average of 14 days in a large vascular series 4
• Gradual approximation techniques (shoelace, vessel loops, or dynamic closure devices) can facilitate delayed closure 6

Monitoring for Complications

• Wound infection: occurs in a minority of cases but requires aggressive treatment; minor infections typically resolve with local wound care 4
• Chronic neuropathy: occurred in 20 of 127 fasciotomies (16%) in one series, often related to delayed diagnosis rather than the fasciotomy itself 4
• Recurrent compartment syndrome: monitor compartment pressures if clinical signs recur, particularly in severe cases 1
• Rhabdomyolysis complications: monitor CPK levels and renal function 2

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Critical Pitfalls to Avoid

• Never delay fasciotomy for pressure measurements alone when clinical signs are present, as late signs like pulselessness and sensory loss indicate tissue damage is already progressing 2
• Never wait for late signs (pulselessness, pallor, paralysis) before intervening, as they indicate already irreversible injury 1
• Never rely solely on palpation for diagnosis; sensitivity is only 54% and specificity is 76% in children 1
• Never elevate the limb excessively, which further decreases perfusion pressure and aggravates ischemia 1
• Never order imaging studies that delay surgical intervention when compartment syndrome is clinically suspected 1
• Irreversible ischemic damage typically occurs within 6-8 hours of symptom onset; fasciotomy should not be postponed beyond this window 1, 7
• Recognize that fasciotomy carries risks including hemorrhage, nerve damage, infection, and difficult wound closure, but these risks are far outweighed by the risk of limb loss from untreated compartment syndrome 2

High-Risk Populations Requiring Intensive Monitoring

• Young men under 35 years with tibial fractures (4-5% develop acute compartment syndrome) 1, 8
• Patients with vascular injuries requiring revascularization 3, 8
• Patients on anticoagulation therapy 1, 8
• Burn injuries, penetrating trauma, and tourniquet use 1
• Monitor these patients every 30-60 minutes for the first 24 hours after injury, assessing pain, neurovascular status, and compartment tension 1