Association Between Vertebral Rotatory Subluxation and the Apical Vertebra in Degenerative Lumbar Scoliosis

Abstract

Objective: To identify the apical vertebra is relate to the occurrence of vertebral rotatory subluxation (VRS) in degenerative lumbar scoliosis.

Methods: In total, 86 patients with degenerative lumbar scoliosis included in this retrospective study were divided into 2 groups: with VRS and without VRS. Coronal and sagittal parameters were measured on whole-spine anteroposterior and lateral radiographs. The impact of VRS on the spine and pelvis parameters was statistically analyzed, and the correlation between the occurrence of VRS and the apical vertebra was analyzed by using logistic regression.

Results: VRS was present in 49 patients with degenerative lumbar scoliosis and absent in 37 patients. Compared with the patients without VRS, the patients with VRS had a smaller lumbar lordosis and thoracic kyphosis (P < 0.05) and a larger apical vertebra translation, apical vertebra tilt angle, Cobb angle, and pelvic incidence-lumbar lordosis (P < 0.05). Logistic regression analysis showed that apical vertebra translation and apical vertebra tilt angle were risk factors for the occurrence of VRS. The receiver operating characteristic curve analysis showed that apical vertebra translation greater than 23.2 mm and apical vertebra tilt angle greater than 11.8° were related to a greater probability of VRS in patients with degenerative lumbar scoliosis.

Conclusions: VRS is an important characteristic to consider in degenerative lumbar scoliosis that can affect the coronal and sagittal alignment. The apical vertebra is correlated with the occurrence of VRS; an apical vertebra translation greater than 23.2 mm and apical vertebra tilt angle greater than 11.8° are highly correlate with the occurrence of VRS.

Keywords: Apical vertebra; Association; Degenerative lumbar scoliosis; Risk factors; Rotatory subluxation.