Correlations between quality of life and sagittal parameters in ankylosing spondylitis after kyphosis correction

Abstract

Objective To explore the impact of the ratio between pelvic tilt (PT) and sacral slope (SS) on the life quality of patients with ankylosing spndylitis (AS) after kyphosis correction. Methods From November 2008 to May 2011, 33 AS patients were reviewed, including 31 males and 2 females, aged from 19 to 58 years old (average, 36 years old). The thoracolumbar kyphosis angle was 35.23°±13.98°(range, 15.12°-74.37°) and the lumbar lordosis angle was 8.68°± 18.27° (range, -23.70°-62.15°). The Scoliosis Research Society (SRS)-22 questionnaire was used to evaluate the quality of life and the Oswestry disability index (ODI) was used to evaluate the condition of pain. The pelvic incidence (PI), PT, SS, sagittal vertical axis (SVA) and osteotomy angle were obtained from standing lateral full-spine radiographs. The correlations were analyzed from the subjective grading and the sagittal parameters in AS patients. Results The osteotomy site was in L1 (5 cases, 21.00°-54.59°, average 32.59°±13.44°), L2 (19 cases, 28.63°-66.24°, average 37.89°±9.26°), L3 (9 cases, 31.78°-60.90°, average 47.05°±9.20°), respectively. The range of osteotomy angle was 39.59°±10.82° (range, 21.00°-66.24°). The subjective grading and spino-pelvic parameters were improved significantly after operation except PI, only postoperative PT/SS(0.93±0.65) and ODI standing (0.60±0.75) (r=0.681,P< 0.05), osteotomy angle (39.59°±10.82°) and satisfaction of management (3.33±0.49) (r=0.478,P< 0.05) had correlation with the subjective grading. Conclusion Compared with the change of PT, SS and SVA, the change of PT/SS is more closely related to the quality of life after operation in AS patients with kyphosis, which should be pay attention to by surgeon when designing operative schemes. Key words: Spondylitis, ankylosing; Kyphosis; Quality of life; Radiography