Spinal intradural extramedullary tumors: the value of intraoperative neurophysiologic monitoring on surgical outcome

Abstract

Nerve sheath tumors and meningiomas account for most intradural extramedullary (IDEM) tumors. These tumors are benign and amenable to complete surgical resection. In recent years, these surgeries are performed with intraoperative neurophysiologic monitoring (IONM) in order to minimize neurological injury, but the evidence for the statistical efficacy of this utility is lacking. This paper evaluates IONM benefits in IDEM tumor resection. Data of patients treated surgically for spinal intradural tumors from 1998 to 2003 was previously collected and analyzed. We retrospectively evaluated patients' charts operated in the years 2011 to 2013. Patients' medical files were reviewed including radiological examinations and electrophysiological reports. The data was collected and evaluated. Forty-one cases of meningioma or nerve sheath tumor resection surgery were performed in the study period. The surgical results were compared to 70 cases of historical controls. Demographic data was similar in these two groups. Sensitivity, specificity, and positive and negative predicted values of IONM were 75, 100, 100, and 97%, respectively. New neurological deficit rate was evident in 10 and 14% for the study and control groups, respectively (not significant). While IONM predicts neurological deficits with high accuracy level, this study does not suggest that there is a significant global benefit of IONM in these cases. As reported by others, in this series, the rate of new neurological deficits in non-monitored cases is similar to the monitored cases series; hence, IONM role in preventing new neurological deficits has yet to be proven.

Intraoperative neurophysiological monitoring for intradural extramedullary spinal tumors: predictive value and relevance of D-wave amplitude on surgical outcome during a 10-year experience

“…To the best of our knowledge, the rate and determinants of D-wave recording in patients with IDEM tumors have not been specifically evaluated until now. 3,7,9,13,[15][16][17] Only Costa et al, 3 in their analysis of SSEP, MEP, and D-wave monitoring in 103 spinal cord procedures (23 ISCTs, 55 IDEM tumors, and 25 myelopathies), reported a 97.1% rate of D-wave monitorability. Indeed, caudal D-wave tracings were obtained in 97 patients and resulted in the most recordable intraoperative neurophysiological parameter in this study, even in compromised patients in whom baseline MEPs were absent.…”

“…The authors found no statistically significant difference in postoperative neurological outcome with the use of IONM during intramedullary spinal cord surgery. In the second paper, by Harel et al, 9 the authors presented a historical control study about the use of IONM without D-wave monitoring in IDEM tumor surgery. They retrospectively compared the neurological outcome after IDEM tumor resection in a group of 41 monitored patients with that of the historical control group of 70 patients who underwent surgery without IONM.…”

“…The few studies that have assessed the utility of IONM during IDEM tumor surgery either did not report the use of Dwaves or reported D-waves only sporadically in a limited cohort of patients. 3,7,9,13,[15][16][17] The purposes of this study were to 1) investigate the rate of IONM ability, especially of D-waves, and evaluate the preoperative factors predicting the possibility of Dwave recording; 2) assess the accuracy of IONM (SSEPs, MEPs, and D-waves) in predicting new postoperative neurological deficits after IDEM tumor resection and statistically compare the accuracy of the 3 modalities by using receiver operating characteristic (ROC) curves; and 3) identify the subgroup of patients with IDEM tumors who are at the highest risk of evoked potential changes during surgery based on uni-and multivariate analyses and who can benefit most from the use of IONM.…”

Intradurale, extramedulläre Tumore: Epidemiologie, Diagnostik und Therapie

“…Insbesondere bei myxopapillären Ependymomen ist eine piece meal-Resektion einer en-bloc-Resektion deutlich unterlegen im Hinblick auf Rezidivrisiko und Gesamtüberleben [16]. Hinsichtlich des neurologischen Outcomes kann das INOM als prädiktiver Faktor für die Erholung neuer postoperativer Defizite nach 6 Monaten herangezogen werden [12].…”

“…Bei der Resektion von intraspinalen, extramedullären Raumforderungen ist ein kontinuierliches, intraoperatives neurophysiologisches Monitoring (IONM) sinnvoll. Insbesondere bei der Rotation des Myelons, Präparation von Tumorgewebe an neuronalen Strukturen und Entfernung des Befundes sollten ein frei laufendes EMG, sensorisch evozierte Potenziale (SEPs) und motorisch evozierte Potenziale (MEPs) abgeleitet werden[12,13].…”