Effect of Bone Flap Surface Area on Outcomes in Decompressive Hemicraniectomy for Traumatic Brain Injury

Decompressive hemicraniectomy to control medically refractory intracranial hypertension and cerebral edema and evacuate mass lesions in traumatic brain injury is a widely accepted treatment paradigm. However, the critical specifications of the bone flap size necessary to control the intracranial pressure (ICP) and provide improved patient outcomes is unknown. We assessed the effect of craniectomy size on the outcomes in surgical decompression for traumatic brain injury.

From 2003 to 2011, 58 cases of decompressive hemicraniectomy were performed for evacuation of hematoma and treatment of refractory ICP in adult patients with traumatic brain injury. The surface area of the decompressive bone flaps was calculated from the postoperative computed tomography scans and correlated with the ICP and Glasgow Coma Scale scores immediately postoperatively and during long-term follow-up.

Decompressive craniectomy led to a statistically significant continued reduction in the preoperative ICP values (24.5 mm Hg; range, 5-30 mm Hg) compared with the postoperative ICP (16.7 mm Hg; range, 1-30; P = 0.006). However, no significant improvement in the preoperative Glasgow Coma Scale (7.47 mm Hg; range, 3-15; vs. 7.50 mm Hg; range, 3-15; P = 0.96) was observed with hemicraniectomy.

For surface areas of 7000-16,000 mm², size was an independent factor in ICP reduction but not for the overall neurologic outcome.