Lower Extremity Somatosensory Evoked Potentials Predict Functional Outcomes in Complete Traumatic Cervical Spinal Cord Injury

Abstract

Traumatic cervical spinal cord injury (tCSCI) is often a debilitating injury, making early prognosis important for medical and surgical planning. Currently, the best early predictors of prognosis are the physical examination, imaging studies, and patient demographics. Despite these factors, patient outcomes continue to vary significantly. The purpose of this study was to evaluate the prognostic value of somatosensory evoked potentials (SSEPs) with functional outcomes in tCSCI patients. A retrospective study was conducted on prospectively collected data from two academic institutions. Patients 18 years and older who had tCSCI and underwent posterior cervical decompression and stabilization with intraoperative neuromonitoring were reviewed. The outcomes of interest were the American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade and ASIA motor score at follow-up. Outcomes measures were assessed via student t-tests, chi-squared tests, and multivariable regression analysis. A total of 79 patients were included. In complete injuries, detectable lower extremity SSEPs were associated with higher ASIA motor scores at follow-up (p=0.002), greater increases in ASIA motor scores at follow-up (p=0.009), and a greater likelihood of clinically important improvement in ASIA motor score (p=0.024). Incomplete, AIS grade C injuries has higher rates of grade conversion (p=0.019) and clinically important improvement in ASIA motor score (p=0.010), compared to AIS grade A or B injuries. The detection of lower extremity SSEP signals during initial surgical treatment of tCSCI is associated with greater improvement in ASIA motor scores postoperatively. The association is most applicable to patients with complete injury.