title: Sagittal Cervical Alignment in Adolescent Idiopathic Scoliosis.
abstract: METHODS
  Retrospective case series of surgically treated adolescent scoliosis patients.
  
  
  OBJECTIVE
  To assess the radiographic changes of cervical kyphosis and identify the possible factors affecting postoperative sagittal cervical kyphosis in surgically treated patients with adolescent idiopathic scoliosis.
  
  
  BACKGROUND
  Cervical kyphosis is a well-recognized phenomenon in patients with adolescent idiopathic scoliosis. Despite recent reports, the prevalence, radiographic changes, and possible factors affecting postoperative sagittal cervical kyphosis are controversial.
  
  
  METHODS
  A retrospective review of a single-center database was performed on 133 consecutive patients with adolescent idiopathic scoliosis treated with long instrumented (more than 5 levels) spine fusion (minimum, 2 years; mean, 3.3 years; range, 2 to 5.5 years). A total of 89 patients met all of the inclusion criteria. Preoperative and postoperative radiographic measurements and patient demographics were investigated.
  
  
  RESULTS
  Postoperative cervical kyphosis was observed in 46 patients. Cobb angle decreased from 48.1° ± 13.1° to 15.4° ± 11.1° at the final follow-up. Cervical kyphosis significantly decreased from 5.5° ± 8.9° preoperatively to -1.5° ± 8.9° at the final follow-up. No difference was observed for T2-T5, T5-T12, lumbar lordosis, sacral slope, pelvic incidence, pelvic tilt, and sagittal vertical axis during the follow-up. Notably, T2 sagittal tilt was significantly increased from preoperatively to the final follow-up. Pearson correlation coefficient test showed a strong correlation between postoperative cervical lordosis and T2 sagittal tilt (r = 0.73; p < .001).
  
  
  CONCLUSIONS
  Despite the significant increase of cervical lordosis, 85% of patients still have a kyphotic or less lordotic cervical spine. The strong positive association between cervical lordosis and T2 sagittal tilt suggests that the sagittal cervical alignment of adolescent idiopathic scoliosis patients is closely related to the global sagittal spine balance rather than thoracic kyphosis.
authors.affiliation: Department of Orthopedic Surgery, National Center for Musculoskeletal Disorders, Murayama Medical Center, 2-37-1 Gakuen, Musashi-Murayama City, Tokyo, Japan. Electronic address: yagiman@gmail.com.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Yagi
authors.affiliation: Department of Orthopedic Surgery, National Center for Musculoskeletal Disorders, Murayama Medical Center, 2-37-1 Gakuen, Musashi-Murayama City, Tokyo, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Iizuka
authors.affiliation: Department of Orthopedic Surgery, National Center for Musculoskeletal Disorders, Murayama Medical Center, 2-37-1 Gakuen, Musashi-Murayama City, Tokyo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hasegawa
authors.affiliation: Department of Orthopedic Surgery, National Center for Musculoskeletal Disorders, Murayama Medical Center, 2-37-1 Gakuen, Musashi-Murayama City, Tokyo, Japan.
authors.forename: Narihito
authors.initials: N
authors.lastname: Nagoshi
authors.affiliation: Department of Orthopedic Surgery, National Center for Musculoskeletal Disorders, Murayama Medical Center, 2-37-1 Gakuen, Musashi-Murayama City, Tokyo, Japan.
authors.forename: Kanehiro
authors.initials: K
authors.lastname: Fujiyoshi
authors.affiliation: Department of Orthopedic Surgery, National Center for Musculoskeletal Disorders, Murayama Medical Center, 2-37-1 Gakuen, Musashi-Murayama City, Tokyo, Japan.
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Kaneko
authors.affiliation: Department of Orthopedic Surgery, National Center for Musculoskeletal Disorders, Murayama Medical Center, 2-37-1 Gakuen, Musashi-Murayama City, Tokyo, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Takemitsu
authors.affiliation: Department of Orthopedic Surgery, National Center for Musculoskeletal Disorders, Murayama Medical Center, 2-37-1 Gakuen, Musashi-Murayama City, Tokyo, Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Shioda
authors.affiliation: Department of Orthopedic Surgery, National Center for Musculoskeletal Disorders, Murayama Medical Center, 2-37-1 Gakuen, Musashi-Murayama City, Tokyo, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Machida
keywords: Adolescent idiopathic scoliosis; Cervical kyphosis; Complication