Intramedullary Lesion Length Predicts ASIA Motor Score Improvement in Patients with Traumatic Locked Facet of the Subaxial Cervical Spine Regardless of Successful Preoperative Closed Skeletal Traction

Introduction: Traumatic locked facet in the subaxial cervical spine may be treated with closed skeletal traction (CST) prior to surgery. Comparison of neurologic outcomes among patients with successful CST versus unsuccessful or no attempted CST are lacking.

Methods: This was a single-center retrospective study of patients treated for cervical locked facet during 2008-2022 at a Level I Trauma Center. Patients with less than 90-day follow-up and cervical injuries other than de facto locked facet were excluded. Demographic and clinical data were analyzed using descriptive and inferential statistics. The primary outcome was improvement in ASIA motor score (AMS) at follow-up.

Results: 67 patients met criteria. Median age was 51 years (interquartile range [IQR]) 31-64). Thirty-one percent (N=21) were female, and locked facet was bilateral in 39% (N=26). Modified 5-factor frailty index (mFI-5) score was 0 in 69%, 1 in 21%, and 2+ in 10%. Admission ASIA impairment scale (AIS) grade was A, B, C, and D in 36%, 13%, 9%, and 42%, respectively, and mean admission AMS was 48.6 (standard deviation [SD] 38). CST was successful in 33 patients (49%), unsuccessful in 22 (33%), and not attempted in 12 (18%). Median admission intramedullary lesion length (IMLL) was 29.05 (IQR 11.4-42.6) and 39 (IQR 18.15-60.05) postoperatively. IMLL and AMS were collinear. At 3-month follow-up, AIS grade was A, B, C, D, and E in 16.4%, 17.9%, 6%, 43.3%, and 16.4%, respectively, and mean follow-up AMS was 69 (SD 36.3). Using previously reported minimum clinically important difference (MCID) of 6 in AMS, 69% (N=46) had improved by 3 months. In multivariable logistic regression for MCID change in AMS, odds ratios (95% Confidence Intervals, P-value) were 1.03 (0.99-1.07, P=0.18) per year of age, 1.03 (1.004-1.07, P=0.025) per mm difference in admission IMLL, 1.28 (0.48-3.44, P-value=0.63) for mFI-5, and 0.72 (0.21-2.4, P=0.59) for successful CST.

Conclusion : Admission IMLL predicted AMS improvement in cervical locked patients with minimum 3-month follow-up, irrespective of successful CST.