One-stage posterior grade 4 osteotomy and bone graft fusion at pseudarthrosis for the treatment of kyphotic deformity with Andersson lesions in ankylosing spondylitis

Abstract

ObjectivesThe optimal surgical procedure for treating kyphotic deformity with Andersson lesions (ALs) in ankylosing spondylitis (AS) patients is controversial. The one-stage posterior osteotomy and bone graft fusion approach is rarely reported. The aim of the present study was to report a new surgical procedure involving one-stage posterior grade 4 osteotomy and bone graft fusion for the treatment of kyphotic deformity with ALs in AS. Patients and methodsEleven patients with ALs in AS were enrolled. One-stage posterior grade 4 osteotomy and bone graft fusion was performed in all patients. Frankel classification and visual analog scale (VAS) were used to evaluate neurologic deficit and the level of back pain pre- and postoperatively, respectively. Radiographic and clinical outcomes were assessed with a mean of 31.5 months follow-up. ResultsLocal kyphosis was corrected from 19.1° to 0.5° after surgery with a mean correction rate of 95%. One Frankel C and 5 Frankel D patients changed to Frankel D and Frankel E, respectively. VAS was reduced from 6.7 to 0.27 at final follow-up. Bone graft fusion was observed at an average of 4.3 months and solid bony fusion was achieved at final follow-up. Average operation time and blood loss were 268.6min and 1009ml, respectively. Three patients developed dural tear complications. There were no neurological or instrumentation complications reported or observed at final follow-up. ConclusionOne-stage posterior grade 4 osteotomy and bone graft fusion is an optional surgical procedure to treat ALs in AS patients. This approach results in reduced blood loss and operation time, satisfactory correction of local kyphosis, and good safety. Successful fusion and good clinical outcomes can also be achieved.