Intraoperative Neuromonitoring Auxiliary Significance of DNEP for MEP-positive Event During Severe Spinal Deformity Surgery

This was a retrospective analysis. OBJECTIVE: The objective of this study was to assess the intraoperative neuromonitoring auxiliary significance of descending neurogenic–evoked potential (DNEP) for motor-evoked potential (MEP) during severe spinal deformity surgery when MEP-positive event occurs. SUMMARY OF BACKGROUND DATA: MEP detection is the most widely applied neurological monitoring technique in spinal deformity surgery. MEP is quite vulnerable to anesthesia, blood pressure, and other intraoperative factors, leading to a high false-positive rate of MEP (3.2%–45.0%), which has greatly interfered with the surgical process. At present, the widely used “presence-or-absence” alarm criteria of MEP is not enough to solve the problem of false positive of MEP. METHODS: A total of 205 cases undergoing severe spinal deformity correction were retrospectively studied. Overall, 74 MEP-positive cases were classified as 2 subgroups: DNEP (+) and DNEP (−) groups. The MEP recovery, wake-up test, and Frankle grade were used to assess the neurological functions. The perioperative and long-term neurological outcomes were assessed. RESULTS: There were significant differences in preoperative scoliosis angle and kyphosis angle between DNEP (−) and DNEP (+) groups. Patients in DNEP (−) group showed more MEP improvement (81.5%), compared with the DNEP (+) group (53.2%). The Wake-up test showed 59.3% motor function deficit cases in DNEP (−) group, which was lower than the 87.2% in DNEP (+) group. More patients in DNEP (−) group had normal nerve function (Frankel level E) than those in DNEP (+) group immediately after surgery, as well as at follow-up. CONCLUSIONS: MEP-positive cases with intraoperative DNEP (−) showed superior prognosis after severe spinal deformity surgery. Intraoperative DNEP could be regarded as an important quantitative tool to assist MEP to monitor neurological injury and can serve as a temporary substitution monitoring technique after MEP is lost.