Purpose: To elucidate the effect of diffuse idiopathic skeletal hyperostosis (DISH) on the clinical results of short-segment lumbar interbody fusion (LIF) for the treatment of degenerative lumbar spinal diseases.
Methods: The 208 patients who underwent one- or two-level LIF were selected as the subjects of this study. Patients with prior lumbar fusion surgery or follow-up <1 year were excluded. Outcome measures were surgery-free survival or the need for further surgery for pseudoarthrosis and/or adjacent segment disease (ASD). The Cox proportional-hazards model was used to identify possible risk factors (DISH, age, sex, number of levels fused, level of the lowest instrumented vertebra, and laminectomy adjacent to the index fused levels) for further surgery.
Results: Among the 208 patients (39 with DISH), 21 patients required further surgery during follow-up. Cox analysis showed that DISH (hazard ratio = 5.46) and two-level fusion (hazard ratio = 2.83) were significant independent predictors of further surgery. Age, sex, level of the lowest instrumented vertebra, and laminectomy adjacent to the index fused levels were not significant predictors.
Conclusions: DISH after short-segment LIF surgery is a significant risk factor for further surgery because of pseudoarthrosis or ASD.
Keywords: Adjacent segment disease; Cox proportional hazards; Diffuse idiopathic skeletal hyperostosis; Lumbar interbody fusion; Pseudoarthrosis.