The clinical analysis of instrumentation failure after corrective surgery for thoracolumbar focal kyphosis

Abstract

To analyze the etiology of instrumentation failure after corrective surgery for thoracolumbar focal kyphosis, and make suggestion for treatment. Retrospective study for 8 patients with thoracolumbar focal kyphosis who underwent surgical treatment and suffered instrumentation failure from June 2005 to December 2011 was made. The surgical procedures included pedicle subtraction osteotomy (PSO), anterior opening-posterior closing osteotomy and correction (AOPC), and posterior vertebral column resection (VCR). The reasons of instrumentation failure were analyzed and revision surgeries were performed. The incidence of instrumentation failure was 6.3%. The average occurrence time was 22.5 months after surgery. Except one had failure in 3 months after surgery, all cases happened after 1 year. In this series, there were 5 cases with post-tuberculosis, 2 cases with post-traumatic kyphosis and 1 case with congenital kyphosis. For the surgical procedure, 7 cases underwent VCR and 1 case AOPC. After the instrumentation failure, all cases had back pain, and 3 of them had combined neurological symptoms. The reasons or risk factors of instrumentation failure included non-fusion of bone graft, VCR procedure, sink of the titanium mesh, insufficiency of anchor sites, and more severe kyphosis. All the 8 cases were treated with revision surgery and got good results. The instrumentation failure of thoracolumbar focal kyphosis is relatively late occurred, and can develop with various reasons. Positive revision surgery is suggested for the instrumentation failure, and good results can be expected.