Frequent neuromonitoring loss during the completion of vertebral column resections in severe spinal deformity surgery.

BACKGROUND CONTEXT: Intraoperative monitoring (IOM) is an essential method for preventing postoperative spinal deficits during posterior vertebral column resection (VCR) surgery for treatment of severe spine deformities, but the IOM features directing at VCR procedures are rarely reported and need to be further clarified.

PURPOSE: To evaluate an important surgical point that will lead to the IOM loss frequently, and then remind the surgeons to pay close attention to impending monitoring changes during posterior VCR surgery.

STUDY DESIGN/SETTING: Retrospective study.

PATIENT SAMPLE: A total of 77 patients with severe spine deformities who underwent posterior VCR and deformity correction surgeries from January 2012 to May 2015 are retrospectively analyzed in our spine center.

OUTCOME MEASURES: IOM (motor-evoked potentials [MEP] and somatosensory-evoked potentials) was used for intraoperative spinal function assessment.

METHODS: Patients were divided into 2 groups according to their preoperative spinal function, including 27 patients with preoperative spinal deficits and 50 patients with spinal normal. And the IOM data during surgery, especially among VCR procedures, were mainly analyzed in the present study.

RESULTS: With the VCR procedure almost complete, most patients showed varying degrees of IOM loss that included 37 cases showing obvious IOM degenerations and 21 cases showing significant IOM loss with alerts immediately. Moreover, the patients with preoperative spinal deficits have more significant decreasing percentage in MEP amplitude (81% vs. 68%, p<.05) than those patients without.

CONCLUSIONS: With the VCR procedure almost complete, surgeons must pay closely attention to the IOM signals and should be ready to take corresponding surgical measures to deal with the impeding monitoring loss.