Preexisting severe cervical spinal cord compression is a significant risk factor for severe paralysis development in patients with traumatic cervical spinal cord injury without bone injury: a retrospective cohort study.

PURPOSE: The objective of this study is to investigate whether preexisting severe cervical spinal cord compression affects the severity of paralysis once patients develop traumatic cervical spinal cord injury (CSCI) without bone injury. METHODS: We retrospectively investigated 122 consecutive patients with traumatic CSCI without bone injury. The severity of paralysis on admission was assessed by the American Spinal Injury Association impairment scale (AIS). The degree of preexisting cervical spinal cord compression was evaluated by the maximum spinal cord compression (MSCC) and was divided into three categories: minor compression (MSCC ≤ 20 %), moderate compression (20 % < MSCC ≤ 40 %), and severe compression (40 % < MSCC). We investigated soft-tissue damage on magnetic resonance imaging to estimate the external force applied. Other potential risk factors, including age, sex, fused vertebra, and ossification of longitudinal ligament, were also reviewed. A multivariate logistic regression analysis was performed to investigate the risk factors for developing severe paralysis (AIS A-C) on admission. RESULTS: Our study included 103 males and 19 females with mean age of 65 years. Sixty-one patients showed severe paralysis (AIS A-C) on admission. The average MSCC was 22 %. Moderate compression was observed in 41, and severe in 20. Soft-tissue damage was observed in 91. A multivariate analysis showed that severe cervical spinal cord compression significantly affected the severity of paralysis at the time of injury, whereas both mild and moderate compression did not affect it. Soft-tissue damage was also significantly associated with severe paralysis on admission. CONCLUSIONS: Preexisting severe cervical cord compression is an independent risk factor for severe paralysis once patients develop traumatic CSCI without bone injury.