Preoperative Spinal Cord Damage Affects the Characteristics and Prognosis of Segmental Motor Paralysis After Cervical Decompression Surgery

Abstract

STUDY DESIGN: Retrospective analysis. OBJECTIVE: To test the hypothesis that preoperative spinal cord damage affects postoperative segmental motor paralysis (SMP). SUMMARY OF BACKGROUND DATA: SMP is an enigmatic complication after cervical decompression surgery. The cause of this complication remains controversial. We particularly focused on preoperative T2-weighted high signal change (T2HSC) on magnetic resonance imaging in the spinal cord, and assessed the influence of preoperative T2HSC on SMP after cervical decompression surgery. METHODS: A retrospective review of 181 consecutive patients (130 males and 51 females) who underwent cervical decompression surgery was conducted. SMP was defined as development of postoperative motor palsy of the upper extremities by at least 1 grade in manual muscle testing without impairment of the lower extremities. The relationship between the locations of T2HSC in preoperative magnetic resonance imaging and SMP and Japanese Orthopedic Association score was investigated. RESULTS: Preoperative T2HSC was detected in 78% (142/181) of the patients. SMP occurred in 9% (17/181) of the patients. Preoperative T2HSC was not a significant risk factor for the occurrence of SMP (P = 0.682). However, T2HSC significantly influenced the severity of SMP: the number of paralyzed segments increased with an incidence rate ratio of 2.2 (P = 0.026), the manual muscle score deteriorated with an odds ratio of 8.4 (P = 0.032), and the recovery period was extended with a hazard ratio of 4.0 (P = 0.035). In patients with preoperative T2HSC, Japanese Orthopaedic Association scores remained lower than those in patients without T2HSC throughout the entire period including pre- and postoperative periods (P < 0.001). CONCLUSION: Preoperative T2HSC was associated with worse severity of SMP in patients who underwent cervical decompression surgery, suggesting that preoperative spinal cord damage is one of the pathomechanisms of SMP after cervical decompression surgery. LEVEL OF EVIDENCE: 3.