Study design: Retrospective case series.
Objective: To test validity of subaxial injury classification (SLIC) treatment recommendations.
Summary of background data: Although SLIC has been tested for reliability, external studies that test the validity of its treatment recommendations are lacking.
Methods: The SLIC score was determined by reviewing imaging studies and clinical records in a consecutive series of 185 patients with subaxial cervical spine trauma presenting to a level 1 spinal injury referral center. Details including attending surgeon responsible for treatment decision, treatment received, and surgical approach were collected.
Results: Treatment received matched SLIC guidelines in 93.6% nonsurgically managed patients and 96.3% surgically managed patients. The mean SLIC score of the surgically treated group of patients was significantly higher than that of the nonsurgical group (7.14 vs. 2.22; P<0.001). Sixty-six patients had a SLIC score of 3 or less, and 94% of them were nonsurgically managed (P<0.001). One hundred two patients had a SLIC score of 5 or more, and 95% of them were surgically managed (P<0.001). Seventeen patients had a SLIC score of 4, and 65% were nonsurgically managed (P=0.032). Injury morphology scores were not predictive of surgical approach. Increasing SLIC scores correlated with increasing complexity of treatment (r=0.77; P<0.001). The distribution of patients with regard to severity of injuries and treatment delivered by the 7 spinal surgeons was comparable. The past practice of these 7 fellowship-trained spine surgeons was individually in agreement with SLIC treatment recommendations.
Conclusion: Our past practice reflects SLIC treatment recommendations for nonsurgical treatment of patients with SLIC scores of 3 or less and surgical treatment of patients with SLIC scores of 5 or more. The use of SLIC as an ordinal severity scale is validated as increasing SLIC scores correlated with increasing complexity of treatment. The injury morphology score did not predict a surgical approach. Significantly higher numbers of patients with a SLIC score of 4 were treated nonsurgically.
Level of evidence: 3.