Minimally invasive versus burr hole craniostomy for chronic subdural haematoma evacuation: a systematic review and meta-analysis

BACKGROUND: Minimally invasive surgery (MIS) has emerged as an appealing alternative to burr hole craniostomy (BHC) for chronic subdural haematoma (cSDH), offering reduced operative trauma and anaesthetic exposure. However, whether these procedural advantages translate into comparable outcomes remains uncertain. This systematic review and meta-analysis aimed to compare the safety, effectiveness, and procedural performance of MIS versus BHC for cSDH evacuation, with attention to device-specific outcomes. METHODS: A systematic search of PubMed, Embase, and CENTRAL (10th November 2025) identified randomised and observational studies directly comparing MIS techniques, including twist-drill craniostomy (TDC), subdural evacuating port systems (SEPS), and YL-1 devices, with BHC. Primary outcomes were reoperation, recurrence, and overall complications. Secondary outcomes included mortality, clinical, and functional recovery, operative time (OT), and length of hospital stay (LOS). Random-effects meta-analysis using REML generated pooled risks ratios (RRs) and mean differences (MDs). Quality and risk of bias was assessed using RoB 2, ROBINS-I, and GRADE. RESULTS: Twenty-seven studies encompassing 3752 patients (MIS 1763; BHC 1989) met inclusion criteria. MIS was associated with significantly higher reoperation risk (18.3% versus 10.2%; RR 1.57; 95% CI 1.17-2.10; P < 0.001) and higher recurrence in SEPS-specific analyses (RR 1.73; 95% CI 1.29-2.32). Overall complications were lower with MIS (RR 0.63, 95% CI 0.42-0.94; P < 0.05). Mortality and postoperative functional outcomes were comparable between groups. MIS substantially reduced OT (MD -24.5 min; P < 0.001) and LOS (MD -1.97 days; P < 0.01). Device-level heterogeneity was marked: SEPS demonstrated poorest durability, whereas YL-1 systems showed lowest complication risk. RCT-specific subgroup analyses demonstrated directional consistency with the main effect for all primary outcomes. Risk of bias was moderate to serious for most included studies, with moderate certainty of evidence. CONCLUSIONS: MIS offers meaningful perioperative advantages but at the cost of reduced durability, particularly for SEPS-based drainage. BHC remains the more definitive intervention for cSDH, although MIS retains an important role in carefully selected patents, particularly where minimising procedural burden or perioperative morbidity is prioritised. Device-specific performance and haematoma morphology should guide surgical strategy as the field moves toward more mechanistically informed, patient-centred care.