Significance of multimodal intraoperative monitoring for the posterior cervical spine surgery

Objective The aim of this study was to evaluate the efficacy of multimodal neurophysiologic intra-operative monitoring (IOM) in a cohort of patients who underwent posterior cervical surgery. Material and methods A total 182 patients were included in this study. Multi-modal intraoperative monitoring (MIOM, somatosensory-evoked potentials: SSEP/transcranial motor-evoked potentials: TCe-MEP/spontaneous-electromyography: S-EMG) was performed in a consecutive series of 129 patients and the other 53 patients (control group) did not. We classified all patients into a high-cervical (H-C) operation group or a low-cervical (L-C) operation group, based on the level of the surgery and analyzed respectively. Results One hundred-eleven cases (86%) showed true negative results. Fourteen patients (9 cases- H-C operation, 5 cases- L-C operation) met the criteria of neurophysiologic changes during operation. Of these, 10 cases were restored to normal during operation spontaneously (7cases) or with surgical manipulation (all 3 cases were related to H-C operation). All unrestored neurophysiologic cases (n = 4) showed new post-operative neurological deficits. Four patients showed neurological deficits without any changes in MIOM (false negative, 3 cases - delayed onset C5 palsy, 1 case - C8 palsy). Conclusions Proper application of MIOM may be useful to detect intraoperative neurological injury during the posterior cervical operations and improve surgical outcomes especially in subgroup of H-C operation. However, the efficacy of MIOM may be restricted to detect and prevent the delayed onset C5 palsy.