How much space is needed for decompressive surgery in malignant middle cerebral artery infarction: Enabling single-stage surgery

Decompressive hemicraniectomy (DCE) is routinely performed for intracranial pressure control after malignant middle cerebral artery (MCA) infarction. Decompressed patients are at risk of traumatic brain injury and the syndrome of the trephined until cranioplasty. Cranioplasty after DCE is itself associated with high complication rates. Single-stage surgical strategies may eliminate the need for follow-up surgery while allowing for safe brain expansion and protection from environmental factors. Assess the volume needed for safe expansion of the brain to enable single-stage surgery. We performed a retrospective radiological and volumetric analysis of all patients that had DCE in our clinic between January 2009 and December 2018 and met inclusion criteria. We investigated prognostic parameters in perioperative imaging and assessed clinical outcome. Of 86 patients with DCE, 44 fulfilled the inclusion criteria. Median brain swelling was 75.35 mL (8.7–151.2 mL). Median bone flap volume was 113.3 mL (73.34–146.1 mL). Median brain swelling was 1.62 mm below the previous outer rim of the skull (5.3 mm to –2.19 mm). In 79.6% of the patients, the volume of removed bone alone was equivalent to or larger than the additional intracranial volume needed for brain swelling. The space provided by removal of the bone alone was sufficient to match the expansion of the injured brain after malignant MCA infarction in the vast majority of our patients A subgaleal space-expanding flap with a minimal offset can provide protection from trauma and atmospheric pressure without compromising brain expansion. •Volume augmentation of the swollen brain is smaller than the volume of removed bone in 79.6% of cases.•An additional Volume of about 50 ​mL would have provided adequate space for the swollen brain in all cases.•Maximum modeled brain swelling outside of the previous skull limit is 2.19 ​mm.