Reduction of midline shift following decompressive hemicraniectomy for malignant middle cerebral artery infarction

Abstract

Background and Purpose Hemicraniectomy is a decompressive surgery used to remove a large bone flap to allow edematous brain tissue to bulge extracranialy. However, early indicators of the decompressive effects of hemicraniectomy are unclear. We investigated whether reduction of mid-line shift following hemicraniectomy is associated with improved consciousness and survival in patients with malignant middle cerebral artery infarctions. Methods We studied 70 patients with malignant middle cerebral artery infarctions (MMI) who underwent hemicraniectomies. Midline shift was measured preoperatively and postoperatively using computed tomography (CT). Consciousness level was evaluated using the Glasgow Coma Scale on postoperative day 1. Patient survival was assessed six months after stroke onset. Results The median time interval between preoperative and postoperative CT was 8.3 hours (interquartile range, 6.1-10.2 hours). Reduction in midline shift was associated with higher postoperative Glasgow Coma Scale scores (P<0.05). Forty-three patients (61.4%) were alive at six months after the stroke. Patients with reductions in midline shifts following hemicraniectomy were more likely to be alive at six months post-stroke than those without (P<0.001). Reduction of midline shift was as­sociated with lower mortality at six months after stroke, after adjusting for age, sex, National Insti­tutes of Health Stroke Scale score, and preoperative midline shift (adjusted hazard ratio, 0.71; 95% confidence interval, 0.62-0.81; P<0.001). Conclusions Reduction in midline shift following hemicraniectomy was associated with improved consciousness and six-month survival in patients with MMI. Hence, it may be an early indicator of effective decompression following hemicraniectomy.