Subcortical mapping and monitoring during insular tumor surgery.
OBJECTIVE
The treatment of insular tumors is controversial. Surgical treatment is associated with a higher morbidity rate than other therapies. The present work presents a new method in which the descending motor pathways are monitored during surgery for insular tumors.


METHODS
Intraoperative monitoring was performed in a combination of 2 techniques. The motor cortex was stimulated with a transcranial electrical stimulus. In addition, direct subcortical stimulation was performed with an electrical anodal monopolar stimulus. Compound motor action potentials (CMAPs) were recorded from target muscles.


RESULTS
Fifteen patients were included in this preliminary study. Following transcranial stimulation, CMAPs were recorded in all cases. Subcortical stimulation was successful in 12 cases. Significant CMAP alterations were recorded in 5 patients. There were no false-negative results in the series.


CONCLUSIONS
The technique presented here is a safe method. It allows a quantitative monitoring of motor function and functional mapping of the pyramidal tract during insular surgery.
Neurosurgical Clinic, Charité-Universitätsmedizin, 12200 Berlin, Germany. theodoros.kombos@charite.de
Theodoros
T
Kombos
Olaf
O
Süss
Peter
P
Vajkoczy
D000200:Action Potentials / Q000502:physiology; D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D001932:Brain Neoplasms / Q000503:physiopathology / Q000601:surgery*; D002540:Cerebral Cortex / Q000503:physiopathology* / Q000601:surgery*; D004525:Efferent Pathways / Q000503:physiopathology / Q000601:surgery; D004558:Electric Stimulation / Q000379:methods*; D004576:Electromyography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D009044:Motor Cortex / Q000503:physiopathology / Q000601:surgery; D019635:Neurosurgical Procedures / Q000379:methods*