title: Spinal fusion after revision surgery for pseudarthrosis in adult scoliosis.
abstract: METHODS
  A retrospective study. OBJECTIVE.: To decipher the incidence, characteristics, functional outcomes, and complications of spinal fusion after revision surgery for recurrent pseudarthrosis in adult patients with scoliosis.
  
  
  BACKGROUND
  While the rate of spinal fusion has been examined in the past, there have been no studies that have examined the incidence, characteristics, functional outcomes, and complications of spinal fusion after pseudarthrosis repair in adult patients with scoliosis.
  
  
  METHODS
  A total of 132 patients with failed spinal fusion surgery for adult scoliosis and painful pseudarthroses were studied. Each patient had an average of 3.7 spinal surgeries before undergoing revision at our institution. In addition to clinical assessment and imaging studies, pseudarthrosis was confirmed intraoperatively in all patients. All patients underwent reinstrumentation and fusion along with adjunctive procedures as needed. Spinal fusion was assessed clinically and radiographically after surgery for a minimum of 40 months. Subjective functional outcomes and complications associated with the procedures were also studied.
  
  
  RESULTS
  The overall incidence of spinal fusion after revision surgery for pseudarthrosis in adult scoliosis was 90%. There was a propensity for pseudarthrosis to recur at the thoracolumbar and lumbosacral junctions. Increasing thoracolumbar kyphosis and loss of sagittal balance were significant risk factors for recurrent pseudarthrosis after revision surgery (mean thoracolumbar kyphosis of 23 degrees and mean sagittal balance of 7.9 cm anteriorly associated with persistent pseudarthrosis). Additionally, patients with multiple preoperative sites of pseudarthroses were at a higher risk for continued pseudarthrosis after surgery. Cigarette smoking, age, and surgical approach did not have any significant correlation with pseudarthrosis. Seventy-two percent of patients were satisfied with the outcome and 80% would have chosen to undergo surgery again if necessary. Thirty-three percent of patients who underwent surgery had some complication related to the surgery.
  
  
  CONCLUSIONS
  Revision surgery for pseudarthrosis repair in adult scoliosis is most successful at attaining fusion when thoracolumbar and overall sagittal alignment are restored as much as possible.
authors: Department of Orthopaedic Surgery, Johns Hopkins Hospital, Johns Hopkins University School of Medicine, Baltimore, MD, USA. dpateder@hotmail.com
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