Characterization of Intraoperative Motor Evoked Potential Monitoring for Surgery of the Pediatric Population with Brain Tumors.

Objective: We investigated the relationship between the reliability of the transcranial or transcortical motor evoked potential (MEP) response and age in pediatric patients aged ≤15 years with brain tumor.

Methods: We retrospectively analyzed the data from 60 consecutive patients aged ≤15 years who had undergone brain tumor surgery that involved intraoperative MEP monitoring from October 2009 to May 2016.

Results: A total of 41 patients with reliable signals (MEP response group) and 19 patients without reliable signals (MEP nonresponse group) were included in the present study. The mean age at surgery, body height, and body weight were significantly greater in the MEP response group than in the MEP nonresponse group. When the MEP success rates during surgery of the pediatric population with brain tumors were analyzed in relation to patient age, the transcortical MEP success rate in the 0-5-year age group (10.0%) was significantly lower than that in the 6-10-year age group (71.4%; P = 0.009) and that in the 11-15-year age group (75.0%; P = 0.015).

Conclusions: The transcortical MEP response was monitored less successfully during brain tumor surgery in patients aged ≤5 years than in patients aged 6-15 years. Although MEP monitoring techniques can be applied during surgery of pediatric populations with brain tumors similar to that used for adult patients, the limitations of the low transcortical MEP response rate in young patients should be considered.