Continuous physical examination during subcortical resection in awake craniotomy patients: Its usefulness and surgical outcome

•Continuous physical examination is useful as a subcortical function monitoring method.•Late neurological outcome of this method is comparable to that of subcortical stimulation.•Combining different subcortical monitoring methods increases monitoring capability.

ObjectivesTo evaluate the value of physical examination as a monitoring tool during subcortical resection in awake craniotomy patients and surgical outcomes.Patients and methodsAuthors reviewed medical records of patients underwent awake craniotomy with continuous physical examination for pathology adjacent to the eloquent area.ResultsBetween January 2006 and August 2015, there were 37 patients underwent awake craniotomy with continuous physical examination. Pathology was located in the left cerebral hemisphere in 28 patients (75.7%). Thirty patients (81.1%) had neuroepithelial tumors. Degree of resections were defined as total, subtotal, and partial in 16 (43.2%), 11 (29.7%) and 10 (27.0%) patients, respectively. Median follow up duration was 14 months. The reasons for termination of subcortical resection were divided into 3 groups as follows: 1) by anatomical landmark with the aid of neuronavigation in 20 patients (54%), 2) by reaching subcortical stimulation threshold in 8 patients (21.6%), and 3) by abnormal physical examination in 9 patients (24.3%). Among these 3 groups, there were statistically significant differences in the intraoperative (p = 0.002) and early postoperative neurological deficit (p = 0.005) with the lowest deficit in neuronavigation group. However, there were no differences in neurological outcome at later follow up (3-months p = 0.103; 6-months p = 0.285). There were no differences in the degree of resection among the groups.ConclusionContinuous physical examination has shown to be of value as an additional layer of monitoring of subcortical white matter during resection and combining several methods may help increase the efficacy of mapping and monitoring of subcortical functions.