Reperfusion Injury (RPI)/White Cord Syndrome (WCS) Due to Cervical Spine Surgery: A Diagnosis of Exclusion

Abstract

Background: Following acute cervical spinal cord decompression, a subset of patients may develop acute postoperative paralysis due to Reperfusion Injury (RPI)/White Cord Syndrome (WCS). Pathophysiologically, this occurs due to the immediate restoration of normal blood flow to previously markedly compressed, and under-perfused/ischemic cord tissues. On emergent postoperative MR scans, the classical findings for RPI/ WCS include new or expanded, and focal or diffuse intramedullary hyperintense cord signals consistent with edema/ischemia, swelling, and/or intrinsic hematoma. To confirm RPI/WCS, MR studies must exclude extrinsic cord pathology (e.g. extramedullary hematomas, new/residual compressive disease, new graft/vertebral fracture etc.) that may warrant additional cervical surgery to avoid permanent neurological sequelae. Methods: In the English literature (i.e. excluding 2 Japanese studies), 9 patients were identified with postoperative RPI/WCS following cervical surgical procedures. For 7 patients, new acute postoperative neurological deficits were appropriately attributed to MR-documented RPI/WCS syndromes (i.e. hyperintense cord signals). However, for 2 patients who neurologically worsened, MR studies demonstrated residual extrinsic disease (e.g. stenosis and OPLL) warranting additional surgery; therefore, these 2 patients did not meet the criteria for RPI/WCS. Results: The diagnosis of RPI/WCS is one of exclusion. It is critical to rule out residual extrinsic cord compression where secondary surgery may improve/resolve neurological deficits. Conclusions: Patients with acute postoperative neurological deficits following cervical spine surgery must undergo MR studies to rule out extrinsic cord pathology before being diagnosed with RPI/WCS. Notably, 2 of the 9 cases of RPI/WCS reported in the literature required additional surgery to address stenosis and OPLL, and therefore, did not have the RPI/WCS syndromes.