Electrophysiologic assessment of intracerebral contusions in closed head injury

To determine whether intracerebral contusions should be evacuated in severe closed head injuries, patients with Glasgow Coma Scale scores < or = 8 and with radiologic evidence of midline shift on computed tomography admitted from 1987 through 1993 to our intensive care unit were monitored with median nerve somatosensory evoked potentials (SSEPs). A total of 44 patients and 84 hemispheres were included in the study. Initial SSEPs, calculated by a quantitative peak-peak amplitude method, were not significantly different between hemispheres that contained localized contusions > or = 2.5 cm, those that had evidence of diffuse injury or punctate lesions < 2.5 cm not considered suitable for surgical evacuation, and those without evidence of parenchymal hemorrhage (mean 14.64 microV, p = 0.43). The SSEPs deteriorated 41.2% from initial baseline levels in diffusely injured and 22.6% in contused hemispheres, whereas in normal-appearing hemispheres, SSEPs improved 51.1% (p = 0.01). The difference in SSEPs, however, was not significant between the contused and diffusely injured hemispheres. The results suggest that in severe closed head injury, cerebral hemispheres without radiologic evidence of structural damage have a high likelihood of improving after initial impact injury. Furthermore, hemispheres with localized contusions showed no more deterioration than those with more diffuse injury, implying that hemispheric electrical deterioration is not related to size of localized contusions but rather to underlying axonal damage. This indicates that surgical evacuation of localized contusions unless accompanied by mass effect is probably not warranted.