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

BACKGROUND In previous studies with traumatic brain injury and ischemic stroke patients, the size of decompressive craniectomy (DC) was reported to be essential for patients' outcome. We aimed at identifying the impact of DC size on treatment results in individuals with aneurysmal subarachnoid hemorrhage (SAH). METHODS The extent of DC in 232 SAH patients who underwent bifrontal or hemi-craniectomy between 01/2003 and 12/2015 was analyzed using semi-automated surface measurements. The study endpoints were the course of intracranial pressure (ICP) treatment after DC, the occurrence of cerebral infarcts, in-hospital mortality and unfavorable outcome at 6 months (defined as modified Rankin scale>3). The associations of DC size with the study endpoints were adjusted for DC timing, patients' age, clinical and radiographic severity of SAH, aneurysm location, and treatment modality. RESULTS The mean DC surface area was 100.9 (±45.8) cm2 . In multivariate analysis, a large DC (>105 cm2 ) was independently associated with the 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 individuals with a small DC size ( 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 patients' outcome in the context of SAH. Particularly a large craniectomy flap (>105 cm2 ) might warrant a better outcome in SAH patients requiring decompressive surgery.