Application of the novel reduction technique in pedicle subtraction osteotomy for thoracolumbar kyphosis secondary to ankylosing spondylitis

English Keywords:Ankylosing spondylitis  Kyphosis  Osteotomy  Subluxation  Reduction technique

English Abstract:

  【Abstract】 Objectives: To investigate the effectiveness of the novel reducer for preventing intra-operative vertebral subluxation in ankylosing spondylitis(AS) patients undergoing pedicle subtraction osteotomy(PSO) for thoracolumbar kyphosis. Methods: A total of 27 AS patients with thoracolumbar kyphosis undegoing PSO between April 2014 and December 2014 was retrospectively reviewed. The thoracic kyphosis(TK), global kyphosis(GK), lumbar lordosis(LL) and sagittal imbalance(SVA) were measured. The subluxation of osteotomized vertebra was defined as the sagittal displacement of more than 5mm between the cranial and caudal vertebrae at the osteotomized level. Results: All patients underwent surgery successfully. All patients were followed up for 5.2±2.4 months(3-12 months). The preoperative TK was 43.2°±10.6°, GK was 72.6°±15.1°, LL was 2.3°±13.5°, SVA was 12.8±4.2cm respectively. The postoperative data were 42.9°±11.8°, 38.2°±12.4°, -38.6°±13.0° and 3.2±5.8cm respectively. The final follow-up data were 42.7°±10.5°, 38.8°±15.2°, -38.4°±11.6° and 3.3±6.4cm respectively。Significant differences were observed in terms of the improvement of GK, LL and SVA(P<0.01). With respect to the mean loss of correction of TK, GK, LL and SVA, no differences were noted(P>0.05). Moreover, no intra-operative vertebral subluxation was observed, except for one transient numbness of the right lower extremity, no other neurological deficit was occurred. Conclusions: The novel reduction technique can effectively prevent intra-operative vertebral subluxation in AS patients undergoing PSO for thoracolumbar kyphosis.