Predictive value of intraoperative neurophysiological monitoring during cervical spine surgery: a prospective analysis of 1055 consecutive patients

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Despite the growing use of multimodal intraoperative monitoring (IOM) in cervical spinal surgery, limited data exist regarding the sensitivity, specificity, and predictive values of such a technique in detecting new neurological deficits in this setting. The authors sought to define the incidence of significant intraoperative electrophysiological changes and new postoperative neurological deficits in a cohort of patients undergoing cervical surgery.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>The authors conducted a prospective analysis of a consecutive series of patients who had undergone cervical surgery during a 5-year period at a university-based neurosurgical unit, in which multimodal IOM was recorded. Sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs) were determined using standard Bayesian techniques. The study population included 1055 patients (614 male and 441 female) with a mean age of 55 years.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>The IOM modalities performed included somatosensory evoked potential (SSEP) recording in 1055 patients, motor evoked potential (MEP) recording in 26, and electromyography (EMG) in 427. Twenty-six patients (2.5%) had significant SSEP changes. Electromyographic activity was transient in 212 patients (49.6%), and 115 patients (26.9%) had sustained burst or train activity. New postoperative neurological deficits occurred in 34 patients (3.2%): 6 had combined sensory and motor deficits, 7 had new sensory deficits, 9 had increased motor weakness, and 12 had new root deficits. Of these 34 patients, 12 had spinal tumors, of which 7 were intramedullary. Overall, of the 34 new postoperative deficits, 21 completely resolved, 9 partially resolved, and 4 had no improvement. The deficits that completely resolved did so on average 3.3 months after surgery. Patients with deficits that did not fully resolve (partial or no improvement) were followed up for an average of 1.8 years after surgery.</jats:p> <jats:p>Somatosensory evoked potentials had a sensitivity of 52%, a specificity of 100%, a PPV of 100%, and an NPV of 97%. Motor evoked potential sensitivity was 100%, specificity 96%, PPV 96%, and NPV 100%. Electromyography had a sensitivity of 46%, specificity of 73%, PPV of 3%, and an NPV of 97%.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Combined neurophysiological IOM with EMG and SSEP recording and the selective use of MEPs is helpful for predicting and possibly preventing neurological injury during cervical spine surgery.</jats:p></jats:sec>

Efficacy of intraoperative monitoring of transcranial electrical stimulation–induced motor evoked potentials and spontaneous electromyography activity to identify acute-versus delayed-onset C-5 nerve root palsy during cervical spine surgery

“…Rather, spEMG was found to be relatively insensitive. 13,23 In the present study, intraoperative nerve root irritation, as identified by significant sustained bursts or, more often, trains of EMG neurotonic discharge, did not correlate with immediate postoperative deficits and had low sensitivity (20%) for detecting acuteonset deltoid muscle weakness. This is not at all surprising since intraoperative spEMG monitoring is not a test of functional neural integrity.…”

“…18 Mechanical injury to the nerve root because of direct tractional force or trauma from a surgical instrument often leads to weakness in the acutely presented innervated muscle, and several studies have shown that tceMEP monitoring is highly effective for rapid identification of an evolving injury leading to weakness that is evident on waking from anesthesia. 1,5,10,12,13,20,22,23 Conversely, mechanisms, such as changes in perfusion and spinal cord shift, may be triggered hours or days after the conclusion of surgery. Since intraoperative neurophysiological monitoring in general and tceMEP surveillance in particular only reflect the status of the nervous system during surgery, it is not at all surprising that neither tceMEP nor spEMG monitoring were of any benefit in identifying C-5 nerve root changes that began long after surgery had ended.…”

“…10,13,20,22,23 In addition to providing neurophysiological surveillance of functional spinal cord integrity, intraoperative neuromonitoring can be applied to detect evolving C-5 nerve root injury during anterior and posterior cervical decompression. 1,5,12 At present, there is conflicting evidence about the sensitivity of spEMG monitoring in the detection of evolving C-5 spinal nerve root injury during anterior or posterior cervical spine surgery.…”

Feasibility and Predictability of Intraoperative Monitoring in Patients with Intradural Extramedullary and Epidural Metastatic Spinal Tumors

“…We can hardly find a result of SSEP change for postoperative sensory deficit in terms of either quantitative or objective description of sensory change in the previous study [24,25]. At this retrospective study, we give up to measure postoperative sensory change as all that we could retrieve was subjective expression of patients about sensory change and vague dermatomal distribution.…”

“…In IDEM and ED metastatic spinal tumour surgery, SSEP might reflect the functional integrity not only of dorsal column but also of motor tract as long as the spinal cord maintains its anatomical integrity throughout the surgery. However, reports of IOM for spinal tumour surgery is relatively rare and frequently mixed up with other spinal procedure, hence only a few of separate study of reporting IOM result of IDEM of ED metastatic spinal tumour surgery can be found [8][9][10].…”