Size does matter: The role of decompressive craniectomy extent for outcome after aneurysmal subarachnoid hemorrhage

Abstract Background and purpose In previous studies in patients with traumatic brain injury and ischemic stroke, the size of decompressive craniectomy (DC) was reported to be paramount with regard to patient outcomes. We aimed to identify the impact of DC size on treatment results in individuals with aneurysmal subarachnoid hemorrhage (SAH). Methods The extent of DC in 232 patients with SAH who underwent bifrontal or hemicraniectomy between January 2003 and December 2015 was analyzed using semi‐automated surface measurements. The study endpoints were course of intracranial pressure (ICP) treatment after DC, occurrence of cerebral infarcts, in‐hospital mortality, and unfavorable outcome at 6 months (defined as modified Rankin scale score >3). The associations of DC size with the study endpoints were adjusted for DC timing, patient age, clinical and radiographic severity of SAH, aneurysm location, and treatment modality. Results The mean DC surface area was 100.9 (±45.8) cm 2 . In multivariate analysis, a large DC (>105 cm 2 ) was independently associated with a lower risk of cerebral infarcts (adjusted odds ratio [aOR] 0.30, 95% confidence interval [CI] 0.16–0.56), in‐hospital mortality (aOR 0.28, 95% CI 0.14–0.56) and unfavorable outcome (aOR 0.51, 95% CI 0.27–0.98). Moreover, SAH patients with a small DC size (<75 cm 2 ) were more likely to require prolonged (>3 days, aOR 3.60, 95% CI 1.37–9.42) and enhanced (aOR 2.31, 95% CI 1.12–4.74) postoperative ICP treatment. Conclusion This is the first study showing the impact of DC size on postoperative ICP control and patient outcome in the context of SAH; specifically, a large craniectomy flap (>105 cm 2 ) might lead to better outcomes in SAH patients requiring decompressive surgery.