P115. Intraoperative sensory signals predict prognosis for patients with traumatic cervical spinal cord injury

Abstract

<h3>BACKGROUND CONTEXT</h3> Traumatic cervical spinal cord injury (tCSCI) is a devasting life-altering event. Prognosis is largely determined by the formal neurological assessment known as International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI), which is graded using the American Spinal Injury Association Impairment Scale grade (AIS grade). AIS grade A is designated as a loss of sacral motor and sensory functions and is associated with the worst prognosis. Many studies have shown that AIS grades are a predictor for neurologic recovery and functional status postinjury. However, the timing of the ISNCSCI exam and AIS grade can greatly influence the reliability of the prognosis. Intraoperative neuromonitoring is routinely used during spine surgery to detect injuries to the spinal cord or nerve roots by measuring signal transmission. However, in patients with SCI, the role of intraoperative neuromonitoring as a potential prognostic tool has not been studied. <h3>PURPOSE</h3> The purpose of this study was to assess if detected signals during intraoperative neuromonitoring portends a greater likelihood of recovery for patients with tCSCI. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort study at a high-volume, academic level I trauma center. <h3>PATIENT SAMPLE</h3> A total of 49 patients undergoing decompression and surgical fixation of following tCSCI. <h3>OUTCOME MEASURES</h3> Improvement in ASIA motor score and AIS grade conversion rate. <h3>METHODS</h3> Patients undergoing decompression and surgical fixation following tCSCI were retrospectively reviewed at a single high-volume, academic level I trauma center. Improvement in ASIA motor score and AIS grade conversion rates at final followup were compared between patients with detectable intraoperative neuromonitoring upper extremity somatosensory evoked potential (SSEP) signals and those without detectable signals. Motor evoked potentials (MEP) were not routinely performed. <h3>RESULTS</h3> A total of 49 patients with tCSCI underwent decompression and surgical fixation with intraoperative neuromonitoring. Seventeen patients with complete SCI and 32 patients with AIS grades B or C on admission were included in the study with a mean followup of 14.3 months. Patients with incomplete SCI had detectable lower extremity SSEPs more often compared to patients with complete SCI (56.3% vs 23.5%, p = 0.028). However, there was no difference in detectable upper extremity SSEPs between complete and incomplete SCI (65.6% vs 58.8%, p=0.638). Of the 17 patients with complete SCI, patients with detectable upper extremity SSEPs cohort had a higher rate of AIS grade conversion compared to the nondetectable cohort (80.0% vs 28.6%, p = 0.034). Furthermore, the detectable upper extremity SSEPs cohort had greater ASIA motor scores on admission (25.9 vs 5.4, p=0.002), at final follow-up (54.0 vs 8.9, and with overall improvement (26.1 vs 3.4, p=0.021) compared to the non-detectable cohort. Patients with detectable lower extremity SSEPs had similar ASIA motor scores on admission (21.5 vs 16.2, 0.609) but higher ASIA motor scores at final followup (57.5 vs 27.1, p=0.041) compared to the nondetectable cohort. Of the 32 patients with incomplete SCI, there was no difference in AIS grade conversion or ASIA motor scores between the detectable and non-detectable SSEP cohorts. <h3>CONCLUSIONS</h3> The presence of upper extremity SSEP signals in patients who present with complete tCSCI portended a better prognosis with greater likelihood of conversion to an incomplete AIS grade and greater motor score at final followup. These results demonstrate an objective and measurable marker of prognosis that can be used for clinical decision making and patient counseling regarding neurologic recovery. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.