Results of Corrective Osteotomy and Treatment Strategy for Ankylosing Spondylitis with Kyphotic Deformity.
BACKGROUND
To report the radiological and clinical results after corrective osteotomy in ankylosing spondylitis patients. Furthermore, this study intended to classify the types of deformity and to suggest appropriate surgical treatment options.


METHODS
We retrospectively analyzed ankylosing spondylitis patients who underwent corrective osteotomy between 1996 and 2009. The radiographic assessments included the sagittal vertical axis (SVA), spinopelvic alignment parameters, correction angle, correction loss, type of deformity related to the location of the apex, and the craniocervical range of motion (CCROM). The clinical outcomes were assessed by the Oswestry Disability Index (ODI) scores.


RESULTS
A total of 292 corrective osteotomies were performed in 248 patients with a mean follow-up of 40.1 months (range, 24 to 78 months). There were 183 cases of single pedicle subtraction osteotomy (PSO), 19 cases of multiple Smith-Petersen osteotomy (SPO), 17 cases of PSO + SPO, 14 cases of single SPO, six cases of posterior vertebral column resection (PVCR), five cases of PSO + partial pedicle subtraction osteotomy (PPSO), and four cases of PPSO. The mean correction angles were 31.9° ± 11.7° with PSO, 14.3° ± 8.4° with SPO, 38.3° ± 12.7° with PVCR, and 19.3° ± 7.1° with PPSO. The thoracolumbar type was the most common. The outcome analysis showed a significant improvement in the ODI score (p < 0.05). Statistical analysis revealed that the ODI score improvements correlated significantly with the postoperative SVA and CCROM (p < 0.05). There was no correlation between the clinical outcomes and spinopelvic parameters. There were 38 surgery-related complications in 25 patients (10.1%).


CONCLUSIONS
Corrective osteotomy is an effective method for treating a fixed kyphotic deformity occurring in ankylosing spondylitis, resulting in satisfactory outcomes with acceptable complications. The CCROM and postoperative SVA were important factors in determining the outcome.
Department of Orthopaedic Surgery, Spine Center, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Korea.
Ki-Tack
KT
Kim
Department of Orthopedic Surgery, Inje University Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
Dae-Hyun
DH
Park
Department of Orthopaedic Surgery, Spine Center, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Korea.
Sang-Hun
SH
Lee
Department of Orthopaedic Surgery, Spine Center, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Korea.
Jung-Hee
JH
Lee
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000150:complications* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000009:adverse effects* / Q000379:methods*; D011183:Postoperative Complications; D012189:Retrospective Studies; D013167:Spondylitis, Ankylosing / Q000150:complications* / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult
Ankylosing spondylitis; Osteotomy; Sagittal alignment