What are the indications for craniotomy in patients with Middle Cerebral Artery (MCA) infarcts?

Indications for Decompressive Craniectomy in MCA Infarcts

Decompressive craniectomy should be performed in patients ≤60 years with unilateral MCA infarction who deteriorate neurologically within 48 hours despite medical therapy, with imaging showing mass effect involving ≥50% of the MCA territory and midline shift. 1

Patient Selection Criteria

Age Considerations

• Patients ≤60 years are the primary candidates for decompressive craniectomy, as this population demonstrates mortality reduction from ~70-80% to ~20-42% and achieves moderate disability or better in 55% of cases, with 18% achieving independence at 12 months 1, 2, 3
• Patients >60 years have significantly worse functional outcomes, with the majority of survivors left with major disability (mRS 4-5), though mortality is still reduced 3, 4

Clinical Indicators

• Progressive deterioration in level of consciousness despite maximal medical management 1, 5
• Development of clinical signs suggesting impending herniation, including bilateral ptosis, particularly with nondominant hemisphere involvement 6
• Exclusion of other reversible causes of deterioration such as hypoperfusion, hypotension, cerebral reinfarction, or seizures 1

Imaging Criteria

• CT hypodensity involving ≥50% of the MCA territory detected within 12 hours of onset 6
• Mass effect with midline shift, compression of the frontal horn, shift of the septum pellucidum, and later shift of the pineal gland 6
• Hypodensity exceeding two-thirds of the MCA territory on enhanced CT predicts malignant MCA infarct with 91% sensitivity and 94% specificity 6
• Hyperdense MCA sign indicating proximal vessel occlusion 6
• Diffusion-weighted imaging (DWI) has 100% accuracy in detecting malignant MCA infarction within 6 hours of onset, compared to only 33% accuracy for CT 7

High-Risk Clinical Features

• History of hypertension and heart failure 6
• Elevated white blood cell count 6
• Involvement of additional vascular territories beyond the MCA 6
• Need for early mechanical ventilation, which increases risk of death 6

Critical Timing Requirements

Surgery must be performed within 48 hours of stroke onset, with earlier intervention (ideally <6 hours) associated with superior outcomes. 1, 7

• Ultra-early decompressive craniectomy (<6 hours) reduces mortality to 8.7% compared to 36.7% for surgery beyond 6 hours and 80% for no operation 7
• Conscious recovery on day 7 occurs in 91.7% with ultra-early surgery versus 55% with delayed surgery and 0% without surgery 7
• Delaying surgery until clinical signs of brainstem compression develop results in significantly poorer outcomes 1
• Surgery performed more than 48 hours after symptom onset does not appear superior to medical management alone 3

Surgical Technique Specifications

Operative Approach for MCA Infarction

• Fronto-parieto-temporo-occipital craniectomy with bone flap diameter ≥12 cm extending up to the midline 6, 1
• Durotomy with enlargement duroplasty 6
• Removal of ischemic brain tissue is NOT recommended for MCA infarction 6
• Intracranial pressure monitor placement is recommended 6
• Consider anterior temporal lobectomy if ICP exceeds 30 mmHg after initial decompression, as this reduces mortality (67% survival with lobectomy versus 0% survival without when ICP >30 mmHg) 7

Contraindications to Tissue Resection

• Unlike cerebellar infarction where tissue removal is indicated, necrotic MCA tissue should not be routinely removed during hemicraniectomy 6
• Concomitant intracranial hematomas may be evacuated if present 6

Expected Outcomes

Mortality Reduction

• Decompressive craniectomy reduces mortality by approximately 50% in appropriate candidates 1
• Mortality decreases from 70-80% with medical management alone to 20-42% with surgical intervention 1, 2, 3

Functional Outcomes in Patients ≤60 Years

• 55% achieve moderate disability or better (mRS ≤3) 1
• 18% achieve functional independence (mRS ≤2) at 12 months 1
• Surgical intervention more than doubles the chance of surviving with at least partial independence 4

Medical Management Considerations

Conservative Measures (Temporizing Only)

• Medical management alone has NOT been proven efficacious for malignant MCA infarction 1
• Osmotherapy with mannitol (0.25-0.5 g/kg IV every 6 hours, maximum 2 g/kg) or hypertonic saline targeting serum osmolality of 300-310 mOsmol/kg may be used as a bridge to surgery 6, 5
• The efficacy of osmotherapy is controversial, as it may theoretically aggravate midline shift by reaching only regions with intact blood-brain barrier 6
• Maintain cerebral perfusion pressure >60 mmHg with volume replacement and/or vasopressors 6, 5
• Elevate head of bed 20-30 degrees to facilitate venous drainage 6, 5
• Avoid antihypertensive agents causing cerebral vasodilation 6, 5

Ineffective Interventions

• No evidence supports that hyperventilation, corticosteroids, furosemide, mannitol, or glycerol improve outcomes in ischemic brain swelling 6
• Despite intensive medical management, mortality remains 50-70% without surgical intervention 6

Common Pitfalls to Avoid

• Do not wait for clinical signs of brainstem herniation before deciding on surgery—the decision should be made early based on imaging and clinical trajectory 1
• Do not rely solely on CT in the first 6 hours, as it shows abnormalities in <50% of patients initially; DWI is far superior for early detection 8, 7
• Physician accuracy in detecting >1/3 MCA territory involvement on CT is only 70-80% with variable reliability 8
• Do not perform craniectomy with inadequate bone flap size (<12 cm), as this reduces efficacy 1
• Ensure coagulation parameters are normalized before surgery, particularly fibrinogen levels in post-thrombolysis patients 6
• Consider preoperative platelet transfusion if patient received antiplatelet agents 6