Factors Associated with Failure of Bony Union After Conservative Treatment of Acute Cases of Unilateral Lumbar Spondylolysis

Abstract

Background: If bone union is expected, conservative treatment is generally selected for lumbar spondylolysis. However, sometimes conservative treatments are unsuccessful. We sought to determine the factors associated with failure of bony union in acute unilateral lumbar spondylolysis with bone marrow edema including contralateral pseudoarthrosis.Methods: This study targeted unilateral lumbar spondylolysis treated conservatively in high school or younger students. Conservative therapy was continued until the bone marrow edema disappeared on MRI and bone union was investigated by CT. We conducted a univariate analysis of sex, age, pathological stage, lesion level complicating the contralateral bone defect, lesion level, and intercurrent spina bifida occulta, and variables with p < 0.1 were considered in a logistic regression analysis. An item with p < 0.05 was defined as a factor associated with failure of bony union.Results: We found 92 cases of unilateral spondylolysis with bone marrow edema and 66 cases were successfully treated conservatively. Failure of bony union in unilateral lumbar spondylolysis with bone marrow edema was associated with advanced pathological stage (p = 0.004), contralateral pseudoarthrosis (p < 0.001), and L5 lesion level (p = 0.002). The odds ratio was 20.0 (95% CI 3.0–193.9) for advanced pathological stage, 78.8 (95% CI 13–846) for contralateral pseudoarthrosis, and 175 (95% CI 8.5–8192) for L5 lesion level.Conclusions: Conservative therapy aiming at bony union is contraindicated in cases of acute unilateral spondylolysis when the pathological stage is advanced, the lesion level is L5, or there is contralateral pseudoarthrotic spondylolysis.

Features of sacral alar fatigue fractures in adolescent athletes with overuse

“…Despite a case report of bilateral sacral alar fatigue fracture 12 , no bilateral case was reported in this study. Fractures on the opposite side have been reported to arise easily when one side fail to fuse 13 and fracture with contralateral bony cleft will easily fail to fuse in lumbar spondylolysis 14 . However, sacral alar fatigue fractures have a high rate of fusion because fractures on both sides are unlikely to occur simultaneously.…”