Radiological analysis of coronal and sagittal spinopelvic parameters in patients with degenerative lumbar kyphoscoliosis

Abstract

Objective: To review and compare radiological parameters between degenerative lumbar kyphoscoliosis (DLKS) and degenerative lumbar kyphosis (DLK), and analyze the relationships between coronal and sagittal deformities and compensatory mechanisms of sagittal balance. Methods: A total of 82 patients with lumbar degenerative deformities were enrolled for our radiographic study at Department of Spinal Surgery, Peking University People's Hospital from January 2016 to May 2017. These patients were divided into two groups: DLKS group (39 patients) with lumbar coronal and sagittal deformities, and DLK group (43 patients) just with lumbar sagittal deformity. Complete spinopelvic radiographic parameters were compared. Results: The Cobb angle and lumbar lordosis of DLKS group were (23.0±11.8)° and (18.2±12.1)°, while the lumbar lordosis of DLK group was (20.4±10.2)°. In DLKS group, Cobb angle had correlations with lumbar lordosis(r=-0.338, P=0.035), and central sacral vertical line distance had significant correlations with thoracolumbar junctional angle (r=0.488, P=0.002) . Moreover, no significant differences of all sagittal spinopelvic parameters were found between two groups (P>0.05). In DLKS group, significant correlations between lumbar lordosis and sacral slope (r=0.617, P=0.000), and correlations between lumbar lordosis and thoracic kyphosis(r=-0.363, P=0.023) were observed. In DLK group, lumbar lordosis showed significant correlations with thoracic kyphosis(r=-0.341, P=0.025) and sacral slope (r=0.772, P=0.000). According to Nash-Moe grading scale of apical vertebral rotation, 10 patients were with Ⅰ-Ⅱ grade while 29 patients with Ⅲ-Ⅴ grade in DLKS group. Conclusions: Both as typical lumbar degenerative deformities, there are some correlations between scoliosis and kyphosis. However, coronal scoliosis may not influent sagittal morphological parameters for DLKS patients. Thoracic curve changes and pelvic backtilt are both important for maintaining the sagittal balance in patients with degenerative lumbar kyphoscoliosis.