Clinical efficacy of asymmetrical pedicle subtraction osteotomy for thoracolumbar kyphotic deformity in ankylosing spondylitis
Objective To analyze the clinical efficacy of asymmetrical pedicle subtraction osteotomy(APSO)in patients with thoracolumbar kyphotic deformity due to ankylosing spondylitis(AS).Methods This retrospective analysis included 96 patients who underwent APSO for thoracolumbar kyphotic deformity due to AS in the Orthopedic Department of Tongchuan People's Hospital from November 2020 to November 2022.There were 62 males and 34 females,aged 18 to 45 years,with an average age of 24.02 years old.Among them,49 had vertebral hypoplasia,36 had incomplete vertebral segmentation,and 11 had mixed-type deformities.The surgery time was(4.15±0.74)hours,the blood loss was(1 055.00±20.41)ml,and the number of fused segments was(7.12±0.96).The follow-up period was 1 year.Standing anteroposterior and lateral radiographs were taken before surgery,half a year after surgery,and at the last follow-up.Coronal plane parameters[coronal Cobb angle and coronal balance distance(CBD)]and sagittal plane parameters[sagittal vertical axis(SVA),global kyphosis(GK),pelvic tilt(PT),sacral slope(SS),lumbar lordosis(LL),osteotomy vertebral angle(OVA),and angle of fused segments(AFS)]were measured to evaluate the corrective effect of the surgery.Visual Analogue Scale(VAS)and Oswestry Disability Index(ODI)were used to assess the pain level and functional disability.Paired t-test was used for statistical analysis.Results Half a year after surgery and at the last follow-up,the coronal plane parameters(Cobb Angle and CBD)and sagittal plane parameters(SVA,GK,PT,SS,and LL)of the patients were improved compared with those before surgery(all P<0.05),but there were no statistically significant differences between those half a year after surgery and at the last follow-up(all P>0.05).The VAS and ODI scores at the last follow-up were lower than those before surgery[(2.27±2.31)points vs.(4.42±2.97)points,(10.74±9.84)points vs.(20.06±14.11)points],with statistically significant differences(t=5.599 and 5.308,both P<0.001).Only 7 patients experienced complications(3 cases of osteotomy vertebral dislocation,2 cases of brachial plexus paralysis,and 2 cases of intraoperative dural tears).Conclusion APSO provides a stable and effective correction for thoracolumbar kyphotic deformity in AS patients,significantly improving quality of life,and is worthy of clinical promotion.