title: Sagittal Alignment Two Years After Selective and Nonselective Thoracic Fusion for Lenke 1C Adolescent Idiopathic Scoliosis.
abstract: METHODS
  Matched cohort.
  
  
  OBJECTIVE
  To evaluate thoracic and thoracolumbar sagittal Cobb angles in patients undergoing either selective thoracic fusion (STF) or nonselective thoracic fusion (NSTF) for Lenke 1C adolescent idiopathic scoliosis (AIS).
  
  
  BACKGROUND
  The Lenke classification is used to guide fusion levels in AIS. For some curve types, including 1C, there is a disparity in practice regarding whether the thoracolumbar/lumbar curve should be included in the arthrodesis. The impact of performing an NSTF on sagittal parameters has not been adequately evaluated.
  
  
  METHODS
  A multicenter database of AIS was queried for patients with right-sided 1C curves treated with posterior correction and fusion. A matched cohort for each group was created based on age, gender, preoperative Cobb angles, and Scoliosis Research Society-22R domain scores. Independent t tests for continuous variables and Fisher exact test for categorical variables were used to compare the STF and NSTF groups.
  
  
  RESULTS
  Thirty-eight patients who underwent NSTF were matched to 38 patients in the STF. An average of 8.0 levels were fused in the STF group and 11.6 in the NSTF group (p < .001). Preoperative and radiographic variables were similar between the two groups. Postoperatively, there was a statistically significant difference between the STF and NSTF sagittal Cobb in the thoracic spine, 26.9° and 21.7° (p = .013). The greatest difference was in the thoracolumbar sagittal Cobb, which increased to 4.3° kyphosis in the STF group and decreased to 9° of lordosis in the NSTF group (p < .001). Residual thoracolumbar/lumbar scoliosis was 25.5° in the STF group and 14.5° in the NSTF group (p < .001).
  
  
  CONCLUSIONS
  STF in 1C curves preserves lumbar motion segments but may be associated with an increase in thoracic and thoracolumbar kyphosis compared to NSTF. As expected, residual thoracolumbar/lumbar scoliosis was less in the NSTF group compared to the STF group. Although the long-term implications of these changes are unknown, consideration of sagittal balance is critical. Following these patients in the medium and long term will provide important information to guide fusion levels.
  
  
  METHODS
  II.
authors.affiliation: OrthoVirginia, 1400 Johnston-Willis Drive, Suite A, Richmond, VA 23235, USA.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Celestre
authors.affiliation: Norton Leatherman Spine Center, 210 East Gray St. Suite 900, Louisville, KY 40202, USA. Electronic address: leahcarreon@nortonhealthcare.org.
authors.forename: Leah Y
authors.initials: LY
authors.lastname: Carreon
authors.affiliation: Department of Orthopaedic Surgery, Washington University School of Medicine, 660 S Euclid Ave, Campus Box 8233, St. Louis, MO 63110, USA.
authors.forename: Lawrence G
authors.initials: LG
authors.lastname: Lenke
authors.affiliation: Department of Orthopaedics, Texas Scottish Rite Hospital for Children, 2222 Wellborn Street, Dallas, TX 75210, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Sucato
authors.affiliation: Norton Leatherman Spine Center, 210 East Gray St. Suite 900, Louisville, KY 40202, USA.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Glassman
keywords: Adolescent idiopathic scoliosis; Sagittal alignment; Selective thoracic fusion; Spine fusion