title: What is the Risk of Developing Proximal Junctional Kyphosis During Growth Friendly Treatments for Early-onset Scoliosis?
abstract: BACKGROUND
  Rib-based and spine-based systems are commonly used distraction-based growth friendly treatments for early-onset scoliosis (EOS). Our primary purpose was to determine the risk of developing postoperative proximal junctional kyphosis (PJK) during distraction-based growth friendly surgery.
  
  
  METHODS
  A multicenter, retrospective, radiographic comparison was performed for a group of 40 children with EOS who were treated with posterior distraction-based implants. PJK was defined as proximal junction sagittal angle (PJA)≥10 degrees and PJA at least 10 degrees greater than preoperative.
  
  
  RESULTS
  Eight subjects (20%) at immediate postoperative follow-up and 11 subjects (27.5%) at minimum 2-year follow-up had developed PJK. The risk of developing PJK between rib-based and spine-based growing systems was not significantly different at immediate postoperative (17% vs. 25%) or at final (25% vs. 31%) follow-ups.Further analysis combining both treatment groups demonstrated that PJK subjects were significantly older at time of initial surgery (7.1 y PJK vs. 5.0 y no PJK). Radiographic comparisons between PJK versus no PJK: Preoperative scoliosis (69.9 vs. 76.0 degrees), thoracic kyphosis (45.1 vs. 28.7 degrees), lumbar lordosis (53.1 vs. 44.0 degrees), PJA (2.2 vs. 2.8 degrees), sagittal vertical axis (1.5 vs. 2.6 cm), pelvic incidence (52.8 vs. 47.4 degrees), pelvic tilt (14.3 vs. 8.7 degrees), and sacral slope (37.7 vs. 35.9 degrees). At both initial postoperative and at final follow-up visits, a significant difference was found for cervical lordosis 32.2 versus 14.0 degrees and 42.0 versus 16.6 degrees, respectively. Risk ratio for developing PJK at final follow-up was 2.8 for subjects with preoperative thoracic hyperkyphosis and was 3.1 for subjects with high pelvic incidence (P<0.05).
  
  
  CONCLUSIONS
  The risk of developing PJK during distraction-based growth friendly treatment for EOS was 20% immediately after implantation and 28% at minimum 2-year follow-up, with no difference observed between rib-based and spine-based treatment groups. As this study identifies a significant risk of developing PJK during the treatment of EOS, it allows clinicians to preoperatively council patients and their families about this possible complication. In addition, several potential risk factors for the development of postoperative PJK were identified, but should be investigated further in future studies.
  
  
  METHODS
  Level III-therapeutic study (retrospective, comparative).
authors.affiliation: *IWK Health Centre, Halifax, NS, Canada †Department of Pediatric Orthopaedics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH ‡Orthopedic Surgery, Shriners Hospital Philadelphia, Philadelphia, PA §Division of Pediatric Orthopaedic Surgery, New York Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, New York, NY ∥Alfred I. duPont Hospital for Children, Wilmington, DE ¶Orthopedic Surgery, Orthopedic and Neurosurgical Specialists, Haddonfield **Orthopaedic Surgery, University of Medicine and Dentistry of New Jersey, Newark, NJ #Shriners Hospital Portland, Children Orthpaedics, Portland, OR ††Primary Children's Hospital, Pediatric Orthopaedics, Salt Lake City, UT.
authors.forename: Ron
authors.initials: R
authors.lastname: El-Hawary
authors.forename: Peter
authors.initials: P
authors.lastname: Sturm
authors.forename: Patrick
authors.initials: P
authors.lastname: Cahill
authors.forename: Amer
authors.initials: A
authors.lastname: Samdani
authors.forename: Michael
authors.initials: M
authors.lastname: Vitale
authors.forename: Peter
authors.initials: P
authors.lastname: Gabos
authors.forename: Nathan
authors.initials: N
authors.lastname: Bodin
authors.forename: Charles
authors.initials: C
authors.lastname: d'Amato
authors.forename: Colin
authors.initials: C
authors.lastname: Harris
authors.forename: Ammar
authors.initials: A
authors.lastname: Al Khudairy
authors.forename: John T
authors.initials: JT
authors.lastname: Smith
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007738:Kyphosis / Q000209:etiology*; D008141:Lordosis / Q000150:complications; D008297:Male; D019857:Osteogenesis, Distraction / Q000009:adverse effects* / Q000379:methods; D011183:Postoperative Complications; D012189:Retrospective Studies; D012306:Risk; D012307:Risk Factors; D012600:Scoliosis / Q000601:surgery*