title: Spondylolisthesis in Operative Adolescent Idiopathic Scoliosis: Prevalence and Results of Surgical Intervention.
abstract: METHODS
  Retrospective, matched cohort.
  
  
  OBJECTIVE
  To evaluate patients with spondylolisthesis who underwent spinal fusion for adolescent idiopathic scoliosis (AIS); compare their overall satisfaction using the Scoliosis Research Society's outcome measure (SRS-22) with that of patients without spondylolisthesis; examine postoperative radiographs to determine slip progression and scoliotic correction; and provide a guide in choosing the lowest instrumented vertebral level.
  
  
  BACKGROUND
  Spondylolisthesis has been reported to occur in 6.2% of patients with AIS. To the authors' knowledge, there is no prior matched-pair study comparing radiographic and clinical outcomes of patients who have undergone spinal fusion for AIS in the setting of spondylolisthesis.
  
  
  METHODS
  Records and radiographs of 349 patients with AIS treated with spinal fusion were reviewed to evaluate for spondylolisthesis. A set of matched controls with AIS but without spondylolisthesis was assembled. Data collected included Lenke curve type, curve magnitude, level and grade of spondylolisthesis, preoperative and postoperative slip angle, number of levels between the fusion and the spondylolisthesis, SRS-22 scores, curve correction, and slip progression.
  
  
  RESULTS
  Sixteen patients with operatively treated AIS (4.58%) also had spondylolisthesis. No patients with low-grade slips had progression of the slip at final follow-up of an average of 4 years. All fusions and listheses were separated by at least 3 levels. No significant differences were seen in postoperative SRS-22 scores between patients with AIS and those with AIS and spondylolisthesis.
  
  
  CONCLUSIONS
  Adolescent idiopathic scoliosis and spondylolisthesis can be treated independently. Powerful curve corrections can be obtained and maintained for at least 4 years in patients with AIS regardless of the presence of spondylolisthesis. Preserving motion of 3 levels between a posterior spinal fusion for AIS and a spondylolisthesis does not contribute to slip progression. According to SRS-22 questionnaire data, patients with concomitant AIS and spondylolisthesis who undergo spinal fusion procedures do well clinically.
authors.affiliation: Department of Orthopaedics, New York University Hospital for Joint Diseases, 212 E. 69th Street, New York, NY 10021, USA.
authors.forename: Stuart
authors.initials: S
authors.lastname: Hershman
authors.affiliation: Department of Orthopaedics, New York University Hospital for Joint Diseases, 212 E. 69th Street, New York, NY 10021, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Hochfelder
authors.affiliation: Department of Orthopaedics, New York University Hospital for Joint Diseases, 212 E. 69th Street, New York, NY 10021, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Dean
authors.affiliation: Department of Orthopaedics, New York University Hospital for Joint Diseases, 212 E. 69th Street, New York, NY 10021, USA.
authors.forename: Burt
authors.initials: B
authors.lastname: Yaszay
authors.affiliation: Department of Orthopaedics, New York University Hospital for Joint Diseases, 212 E. 69th Street, New York, NY 10021, USA. Electronic address: baron.lonner@nyumc.org.
authors.forename: Baron
authors.initials: B
authors.lastname: Lonner
keywords: Adolescent idiopathic scoliosis; Lowest instrumented vertebral level; Scoliosis Research Society Questionnaire (SRS-22); Spondylolisthesis