The influence of the profile of brain retractors on regional cerebral blood flow in the rat.

Self-retaining brain retractors with different profiles have been constructed in order to decrease the risk of cerebral ischaemia during intracranial operations. Flat retractors are more easy to handle than curved, because the flat retractors can be bent into the desirable shape. To estimate the regional cerebral blood flow (rCBF) using retractors with three different profiles (flat, flat with rounded edges and curved) autoradiography with carbon-14 (14C) iodoantipyrine was performed in rats. After craniotomy over the parietal cortex lead weights with the three different profiles corresponding to 20 mm Hg of brain retractor pressure (BRP) were placed on the cortex for 15 minutes. rCBF (average values) in cortex beneath the flat retractors was 80 ml/100 gm/min (n = 10), for flat ones with rounded edges 90 ml/100 gm/min (n = 5) and for the curved retractors 75 ml/100 gm/min (n = 5). The differences were not significant. Even with a BRP of 30 mm Hg no differences were observed between flat (n = 3) and curved (n = 3) weights. In control animals craniotomy showed no influence on the rCBF (n = 3). No further risk for ischaemic nerve cell damage could be demonstrated by using the most easily-handled retractors, the flat ones, instead of those more or less curved.