The role of multi-modal intra-operative neurophysiological monitoring in corrective surgeries for thoracic tuberculosis with kyphosis

Abstract

Objective: The aim of this study was to assess the performance and utility of motor evoked potentials (MEP) and somatosensory evoked potentials (SSEP) during corrective surgery for thoracic tuberculosis with kyphosis (TTK).

Methods: 68 patients (mean age 31.7 ± 20.3 years) who underwent corrective surgery for TTK from 2012 to 2019 were included in this retrospective study. Patients were neurologicaly evaluated before and after surgery with systematic neurologic examinations. Intraoperative neurophysiological monitoring (IONM) with SSEP and MEP was carried out. A receiver operating characteristic (ROC) curve and area under ROC curve (AUC) were used to identify the diagnostic accuracy of potential recovery.

Results: IONM alerting occurred in 12 surgeries (12/68, 17.6%), of which 6 were SSEP alerting, 2 MEP alerting, and 4 combinations of both SSEP and MEP. Among the 12 cases where there was IONM alerting, 3 (25%) had postoperative neurological deficits(PND), whereas one patient had PND without IONM alerting. IONM sensitivity and specificity were 0.75 (95% CI 0.22-0.99) and 0.86 (95% CI 0.74-0.93) respectively. Positive predictive value (PPV) and negative predictive value (NPV) were 0.25 and 0.98 respectively. The AUC of evoked potential recovery in diagnosing PND was 0.884.

Conclusion: Our study showed that multi-modal IONM with SSEP and MEP can effectively indicate a potential neural injury and predict PND during TTK corrective surgery.

Level of evidence: Level IV, Therapeutic Study.

Figure 1. A, B.

MEP, SSEP alerting. Motor-evoked potentials (panel A) and somatosensory-evoked potentials (panel B) decrease generating an alert by ≥50%. MEP, motor-evoked potential; SSEP, somatosensory-evoked potential.

Figure 2.

Patients’ selection protocols. Seventy-two patients were diagnosed thoracic tuberculosis with kyphosis. A total of 68 cases with successful multimodal IONM with SSEP and MEP were finally available and included for further analysis, 12 cases had intraoperative alerting, and 4 patients had postoperative neurological deficits. IONM, intraoperative neurophysiological monitoring; MEP, motor-evoked potential; SSEP, somatosensory-evoked potential.

Figure 3.

ROC curve and AUC. The AUC of 0.884 manifests an excellent accuracy of potential recovery in diagnosing postoperative neurological deficit. ROC, receiver operating characteristic; AUC, area under receiver operating characteristic curve.