Intraoperative Neurophysiological Monitoring During Resection of Posterior Fossa Lesions

Abstract

Objective: To study the benefits of intraoperative neurophysiological monitoring during the resection of posterior fossa lesions.

Study Design: Cross-sectional study.

Place and Duration of Study: Department of Neurosurgery, Combined Military Hospital (CMH), Rawalpindi Pakistan, from Apr 2020 to Mar 2022.

Methodology: One hundred and sixty-nine diagnosed posterior fossa lesions, including cerebellopontine angle tumours, were included. The chi-square test was used to test the association of new neurological deficits among different pathologies. In addition, the sensitivity and specificity of IONM were also calculated for risk identification of new neurological deficits.

Results: The mean age of the patients was 35.75±9.31 years. No clinical signs and symptoms were associated with the new neurological deficit (p-value> 0.05). The majority (72.8%) of the surgeries were declared successful, as only 46(27.2%) surgery outcome was “Poor”. The sensitivity of the IONM monitoring was 51.61%, specificity 68.42%, positive predictive value 66.67% and negative predictive value 53.61%.

Conclusion: Intraoperative neuro-monitoring plays a vital role in obtaining successful results in posterior fossa surgeries because the prevalence of neurological deficits in the posterior fossa lesions was very high compared to the other surgeries.
Keywords: Electroencephalogram (EEG), Electromyography (EMG), Intraoperative neuro-monitoring (IONM), Posterior fossa
lesion surgeries, Somatosensory evoked potential, Transcranial motor evoked potentials (tcMEPs).