title: Distraction-Based Treatment Maintains Predicted Thoracic Dimensions in Early-Onset Scoliosis.
abstract: METHODS
  Retrospective cohort study.
  
  
  OBJECTIVE
  Examination of distraction-based treatment effect on thoracic dimensions in patients compared to predicted individual normal values, at initial treatment and subsequent follow-up after lengthenings.
  
  
  BACKGROUND
  Change in thoracic dimensions and spine length is an important outcome measure in treatment of children with early-onset scoliosis; however, it is difficult to use to make comparisons between patients and the normal population because of the heterogeneous nature of early-onset scoliosis.
  
  
  METHODS
  Early-onset scoliosis patients treated with distraction-based therapy who had radiographic parameters (pelvic inlet width, chest width, and thoracic height) preoperatively, immediately postoperatively, and at a minimum 5-year follow-up were included. Individual thoracic measurements were compared with predicted normal measures based on pelvic inlet width, and expressed as a percentile of predicted measure.
  
  
  RESULTS
  Comparisons were made in 41 patients; mean age at time of primary surgery was 4.5 years, and median follow-up was 6.5 years. Thoracic height percentile increased from a mean preoperative value of .78 to a postoperative percentile of .88 (p < .001); at long-term follow-up, it was .85. Absolute thoracic height increased at all 3 time points: 141.6, 159.79, and 203.45 mm, respectively Mean chest width was similar preoperatively (170 mm) and immediately postoperatively (166.5 mm) but increased at latest follow-up (206.9 mm). Chest width percentile was similar at all 3 times (.93, .90, and .91).
  
  
  CONCLUSIONS
  Distraction-based treatment increases absolute thoracic height over time. There is significant improvement in the thoracic height percentile normalized after initial surgery, which was maintained over time. Measuring expected gains as a percentile normalized for pelvic width may be a more relevant outcome measure compared with measuring only absolute values.
authors.affiliation: Department of Orthopaedic Surgery, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA. Electronic address: Michael.Glotzbecker@childrens.harvard.edu.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Glotzbecker
authors.affiliation: Department of Orthopaedic Surgery, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
authors.forename: Meryl
authors.initials: M
authors.lastname: Gold
authors.affiliation: Department of Orthopaedic Surgery, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
authors.forename: Patrica
authors.initials: P
authors.lastname: Miller
authors.affiliation: San Diego Center for Spinal Disorders, 4130 La Jolla Village Dr #300, La Jolla, San Diego, CA 92037, USA.
authors.forename: Behrooz A
authors.initials: BA
authors.lastname: Akbarnia
authors.affiliation: Orthopedics, Texas Scottish Rite Hospital for Children, 2222 Welborn St. Dallas, TX 75219, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Johnston
authors.affiliation: Hospital Universitario La Paz, Pedro Rico 31. 8 G, Madrid 28029, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Sanchez Perez Grueso
authors.affiliation: Department of Orthopaedics, Nemours/Alfred I DuPont Hospital for Children, 1600 Rockland Road, Wilmington, DE 19899, USA.
authors.forename: Suken A
authors.initials: SA
authors.lastname: Shah
authors.affiliation: Department of Orthopaedic Surgery, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
authors.forename: John
authors.initials: J
authors.lastname: Emans
keywords: Distraction-based therapy; Early onset scoliosis; Pulmonary outcomes