Prognostic significance of the zone of partial preservation (ZPP) within 72 h after complete cervical spinal cord injury: A novel MRI-based approach.

OBJECTIVES: To investigate the prognostic value of the Zone of Partial Preservation (ZPP) within 72 h after cervical spinal cord injury (CSCI) with the American Spinal Injury Association Impairment Scale (AIS) A, and to examine the utility of combining magnetic resonance imaging (MRI) findings with ZPP assessment. STUDY DESIGN: A retrospective case series. SETTING: Our institute. PARTICIPANTS/METHODS: The study participants were seventy patients with an initial diagnosis of complete CSCI within 72 h after injury. The impact of sensory or motor ZPP lengths on the rates of conversion to AIS B/C/D and sensory and motor score recovery at three months after injury was investigated. MRI-based sensory/motor ZPP length was defined as the number of segments between the sensory/motor ZPP and the presumptive primary injured segment of the spinal cord inferred from MRI, and its relevance was also investigated. RESULTS: A total of 9 improved to AIS B, 6 to C, and 1 to D. Sensory ZPP length ≥ 12, and MRI-based sensory ZPP length ≥ 10 were predictive of conversion to AIS C/D with an odds ratio of 18.5 (95% CI, 2.2-154.0, p < 0.05). Significantly greater motor score gain was demonstrated in individuals with longer lengths of MRI-based sensory ZPP (p < 0.05). CONCLUSION: Long sensory ZPP length within 72 h after injury could be a prognostic factor of conversion to AIS C/D and motor score gain in individuals with sensorimotor complete CSCI. ZPPs could be more useful for predicting recovery potential when combined with MRI findings.