Is determination between complete and incomplete traumatic spinal cord injury clinically relevant? Validation of the ASIA sacral sparing criteria in a prospective cohort of 432 patients.

STUDY
DESIGN: Prospective multicenter longitudinal cohort study.
OBJECTIVE: To validate the prognostic value of the acute phase sacral sparing measurements with regard to chronic phase-independent ambulation in patients with traumatic spinal cord injury (SCI).
SETTING: European Multicenter Study of Human Spinal Cord Injury (EM-SCI).
METHODS: In 432 patients, acute phase (0-15 days) American Spinal Injury Association (ASIA)/International Spinal Cord Society neurological standard scale (AIS) grades, ASIA sacral sparing measurements, which are S4-5 light touch (LT), S4-5 pin prick (PP), anal sensation and voluntary anal contraction; and chronic phase (6 or 12 months) indoor mobility Spinal Cord Independence Measure (SCIM) measurements were analyzed. Calculations of positive and negative predictive values (PPV/NPV) as well as univariate and multivariate logistic regressions were performed in all four sacral sparing criteria. The area under the receiver-operating characteristic curve (AUC) ratios of all regression equations was calculated.
RESULTS: To achieve independent ambulation 1-year post injury, a normal S4-5 PP score showed the best PPV (96.5%, P<0.001, 95% confidence interval (95% CI): 87.9-99.6). Best NPV was reported in the S4-5 LT score (91.7%, P<0.001, 95% CI: 81.6-97.2). The use of the combination of only voluntary anal contraction and the S4-5 LT and PP sensory scores (AUC: 0.906, P<0.001, 95% CI: 0.871-0.941) showed significantly better (P<0.001, 95% CI: 0.038-0.128) discriminating results in prognosticating 1-year independent ambulation than with the use of currently used distinction between complete and incomplete SCI (AUC: 0.823, P<0.001, 95% CI: 0.781-0.864).
CONCLUSIONS: Out of the four sacral sparing criteria, the acute phase anal sensory score measurements do not contribute significantly to the prognosis of independent ambulation. The combination of the acute phase voluntary anal contraction and the S4-5 LT and PP scores, predicts significantly better chronic phase-independent ambulation outcomes than the currently used distinction between complete and incomplete SCI. SPONSORSHIP: This study was granted by 'Acute Zorgregio Oost' and the 'Internationale Stiftung für Forschung in Paraplegie (IFP)'.