Hemicraniectomy for massive cerebral infarction: Evoked potentials as presurgical prognostic factors

In patients with massive hemispheric infarctions, mortality exceeds 80% with medical therapy alone. In certain conditions hemicraniectomy may result in meaningful survival. We studied presurgical clinical and electrophysiological parameters that may serve as prognostic factors to assess efficacy of decompressive surgery. We evaluated 26 consecutive patients with severe focal neurological deficit, deterioration of consciousness, and massive hemispheric infarction by cranial computerized tomography who underwent hemicraniectomy. Clinical examination included pupillary size and reaction, and determination of level of consciousness on an hourly basis. Median nerve somatosensory evoked potentials and brainstem auditory evoked potentials were obtained before and after hemicraniectomy. Outcome was assessed by using the Barthel Index. Clinical and evoked potential data were correlated with the outcome. Fisher's Exact Test was applied to establish statistical significance. With surgery 18 of 26 patients survived on an average intensive care treatment of 29.6 (+/-27.5) days. Barthel Index at discharge was 61.7 (+/-24.4) in survivors. Presurgical pupillary reaction, level of consciousness, and somatosensory evoked potentials were not found to correlate with outcome. In contrast, presurgical brainstem auditory evoked potentials showed a significant correlation with survival (P<.05). All patients with good outcomes (Barthel Index >/=60: n=12, 46.1%) had normal brainstem auditory evoked potentials before surgery. Clinical parameters did not reliably forecast prognosis in patients with massive cerebral infarction treated with hemicraniectomy.