A REVIEW OF BRAIN RETRACTION AND RECOMMENDATIONS FOR MINIMIZING INTRAOPERATIVE BRAIN INJURY

BRAIN RETRACTION IS required for adequate exposure during many intracr anial procedures. The incidence of contusion or infarction from overze alous brain retraction is probably 10% in cranial base procedures and 5% in intracranial aneurysm procedures. The literature on brain retrac tion injury is reviewed, with particular attention to the use of inter mittent retraction. Intraoperative monitoring techniques-brain electri cal activity, cerebral blood flow, and brain retraction pressure-are e valuated. Various intraoperative interventions-anesthetic agents, posi tioning, cerebrospinal fluid drainage, operative approaches involving bone resection or osteotomy, hyperventilation, induced hypotension, in duced hypertension, mannitol, and nimodipine-are assessed with regard to their effects on brain retraction. Because brain retraction injury, like other forms of focal cerebral ischemia, is multifactorial in its origins, a multifaceted approach probably will be most advantageous i n minimizing retraction injury. Recommendations for operative manageme nt of cases involving significant brain retraction are made. These rec ommendations optimize the following goals: anesthesia and metabolic de pression, improvement in cerebral blood flow and calcium channel block ade, intraoperative monitoring, and operative exposure and retraction efficacy. Through a combination of judicious retraction, appropriate a nesthetic and pharmacological management, and aggressive intraoperativ e monitoring, brain retraction should become a much less common source of morbidity in the future.