A role for motor and somatosensory evoked potentials during anterior cervical discectomy and fusion for patients without myelopathy: Analysis of 57 consecutive cases

Abstract

Background:Although the usage of combined motor and sensory intraoperative monitoring has been shown to improve the surgical outcome of patients with cervical myelopathy, the role of transcranial electric motor evoked potentials (tceMEP) used in conjunction with somatosensory evoked potentials (SSEP) in patients presenting with radiculopathy but without myelopathy has been less clear.Methods:We retrospectively reviewed all patients (n = 57) with radiculopathy but without myelopathy, undergoing anterior cervical decompression and fusion at a single institution over the past 3 years, who had intraoperative monitoring with both tceMEPs and SSEPs.Results:Fifty-seven (100%) patients presented with radiculopathy, 53 (93.0%) with mechanical neck pain, 35 (61.4%) with motor dysfunction, and 29 (50.9%) with sensory deficits. Intraoperatively, 3 (5.3%) patients experienced decreases in SSEP signal amplitudes and 4 (6.9%) had tceMEP signal changes. There were three instances where a change in neuromonitoring signal required intraoperative alteration of the surgical procedure: these were deemed clinically significant events/true positives. SSEP monitoring showed two false positives and two false negatives, whereas tceMEP monitoring only had one false positive and no false negatives. Thus, tceMEP monitoring exhibited higher sensitivity (33.3% vs. 100%), specificity (95.6% vs. 98.1%), positive predictive value (33.3% vs. 75.0%), negative predictive value (97.7% vs. 100%), and efficiency (91.7% vs. 98.2%) compared to SSEP monitoring alone.Conclusions:Here, we present a retrospective series of 57 patients where tceMEP/SSEP monitoring likely prevented irreversible neurologic damage. Though further prospective studies are needed, there may be a role for combined tceMEP/SSEP monitoring for patients undergoing anterior cervical decompression without myelopathy.

Intraoperative Neuromonitoring for Anterior Cervical Spine Surgery

“…15,17,18,20,22 Six studies analyzed patients monitored with a unimodal technique; 11,15,16,18,19,22 five of which used SSEP, 11,15,18,19,22 and one of which used MEP 16 (Table 3). 11,14–22 …”

“…Indications for ACSS were strictly limited to myelopathy or radiculopathy in three studies, 15,16,20 whereas the remaining studies included a small percentage of patients treated for infection, tumor, trauma, and ossified posterior longitudinal ligament (Table 1). 14,17–19,21,22 …”

“…11,14,15,18–20,22 One study used only upper extremity SSEP monitoring. 18 Two studies did not report the technique for SSEP monitoring.…”

“…18 Two studies did not report the technique for SSEP monitoring. 17,21 Criteria for a significant alert were a decrease in amplitude of 50% or an increase in latency of 10% in three studies, 18,20,22 a 30% to 50% decrease in amplitude in one study, 14 and a 60% decrease in amplitude in one study (Table 3). 17 …”

Multi-channel motor evoked potential monitoring during anterior cervical discectomy and fusion

“…Recent studies have provided additional evidence for the usefulness of Multi-channel MEPs (at least 8 muscles) during spinal surgery (Ito et al, 2013), and other studies suggested that MEPs demonstrated greater sensitivity during ACDF surgery than SSEPs (Lee et al, 2006, Xu et al, 2011). However, since no previous studies have investigated multi-channel MEPs during ACDF surgery, the current study aims to evaluate the usefulness of multi-channel MEPs monitoring on post-operative motor deficits of ACDF surgery.…”