The treatment of Andersson lesion with kyphosis in ankylosing spondylitis by posterior wedge osteotomy

English Keywords:Osteotomy  Andersson lesion  Ankylosing spondylitis  Visual analog scale  Oswestry disability index

English Abstract:

  【Abstract】 Objectives: To assess the efficacy and feasibility of posterior wedge osteotomy in treating kyphosis with Andersson lesion(AL) in ankylosing spondylitis. Methods: 15 ankylosing spondylitis patients(14 males and 1 female) with kyphosis and Andersson lesion with an average age of 35.7±6.1 years old(22-44 years) were retrospectively studied(January 2012 to January 2014). All patients suffered from back pain and severe kyphosis deformity. The local kyphosis(LK) was 51.9°±15.1°, the global kyphosis(GK) was 61.6°±27.5°, the VAS score of back pain was 6.8±0.8 and the ODI was (55.4±12.8)% preoperatively. The Frankel grading of preoperative neurological function was 1 patient in grade C, 3 patients in grade D, and 11 patients in grade E. All patients were performed posterior wedge osteotomy. Before posterior wedge osteotomy, all sclerosis bone was scraped until reaching the healthy cancellous bone. The time of follow-up was at least two years. Radiographic parameters (LK, GK, thoracolumbar kyphosis, lumbar lordosis, pelvic tilt, sacral slope) and clinical efficacies(VAS, ODI) were assessed. The CT scan of the entire spine was obtained preoperatively and at the 2-year follow-up to assess the condition of screw insertion and the healing of fracture. The Bridwell interbody fusion grading system was used to assess the healing of fracture. Results: All patients were operated successfully. The average surgery time was 279.4±32.9min, and the average blood loss was 1066.1±466.1ml. There was one dura tear which was repaired during operation. One patient suffered from pneumonia and recovered after antibiotic treatment. The average time of follow-up was 27.1±2.4 months(24-32 months). At the time of 2-year follow-up, the LK was 7.9°±19.0° with an average correction of 44.6°±9.1°, the GK decreased to 21.3°±10.6°(P<0.05), the VAS scores of back pain improved to 0.7±0.6(P<0.05), the ODI improved to (15.6±4.3)%(P<0.05). The CT scan showed solid fusion at the level of AL, and no loose or breaking of internal fixation. All patients achieved grade 1 healing. No major complication occurred. Conclusions: Posterior wedge osteotomy through AL can be used to correct the kyphosis in ankylosing spondylitis, with good fusion and deformity correction, and with satisfactory clinical outcomes.