gms | German Medical Science

Objective: The term “anaesthesia for awake surgery” is an oxymoron and despite of the widespread use of awake craniotomy procedures there is still no consensus on an anaesthetic regimen. The most common anaesthetic regimens for awake craniotomies are total intravenous anaesthesia (TIVA) and regional anaesthesia with slight sedation (RAS). In a previously performed study we could reveal a signifcant impact on the DO80-picture-naming test, fingertapping and other cognitive functions due to sedation, which in theory could compromise brain mapping intraoperatively. Whether speech and motor function are compromised to the same extent due to sedation is not yet known. The major question of this study was to examine, whether there is a difference between the relative deteriorations of motor and speech function due to sedation.

Method: We prospectively examined patients undergoing surgery in the orthopaedic department or ENT-Department under total intravenous anaesthesia (TIVA; n=20) and under regional anaesthesia with slight sedation (RAS; n=18). We deliberately did not examine neurosurgical patients, because we wanted to exclude bias caused by perioperative neurological impairment. The DO80 picture naming test and the finger tapping test were performed. Each test was conducted three times for every patient in both groups, once prior to surgery and twice within about 30 minutes after the end of sedation. The relative deteriorations of both tests in both groups were calculated for the two postoperative testing times vs. the preoperative condition, respectively.

Results: Besides the significant deterioration in both tests in both groups, we found a significant difference of the relative deterioration between both tests for both groups and testing times, favouring the DO80-Test (p<0.01, Wilcoxon-Test, SPSS). The relative improvement of motorfunction between the first and second postoperative testing times was larger than the relative improvement for speech function in both groups.

Conclusions: Intraoperative sedation may compromise motor function to a greater extent than speech. This should be considered during awake craniotomy, as patients may seem to be adequate enough for neuropsychological testing according to their speech function, though there might be limitations with a significantly greater extent for motor tests in comparison to the DO80-test.