title: Radiological Assessment of the Effect of Congenital C3-4 Synostosis on Adjacent Segments.
abstract: METHODS
  Retrospective case series.
  
  
  OBJECTIVE
  To assess the effect of non-kyphotic aligned congenital C3-4 synostosis on the adjacent segment in 10 patients.
  
  
  BACKGROUND
  In the cervical spine, fusion disease at the adjacent motion segments may be a risk factor for potential neurological compromise and death.
  
  
  METHODS
  Radiograms of 10 patients 13 to 69 years of age presenting with neck/shoulder discomfort or pain with or without trauma history were examined. C3-4 synostosis was found incidentally in all patients on routine examination radiographs of cervical spine.
  
  
  RESULTS
  Adjacent segment disease (ASD) was not found in the three patients younger than 39 years of age. Five of the 10 (50%) patients, including a 67-year-old man, did not develop spondylosis in any of the cervical mobile segments. Spondylosis was observed only in the caudal 1-2 mobile segments in the remaining five patients. The youngest was a 40-year-old male who had spondylosis in the two caudal mobile segments (C4-5 and C5-6). Spondylosis was limited to the two close caudal mobile segments and was not in the cranial segments. Flaring of the lower part of synostotic vertebra associated with advanced narrowed degenerate disc was evident in five patients.
  
  
  CONCLUSIONS
  Mobile segment spondylosis in the individuals with congenital monosegment C3-4 synostosis over age of 40 years may be a natural manifestation of aging and is not solely an adjacent segment disease directly and fully related with congenital C3-4 synostosis.
authors.affiliation: Department of Orthopaedic, Jeju Halla General Hospital, Jeju, Korea.
authors.forename: Myung-Sang
authors.initials: MS
authors.lastname: Moon
authors.affiliation: Department of Orthopaedic, Jeju Halla General Hospital, Jeju, Korea.
authors.forename: Min Geun
authors.initials: MG
authors.lastname: Yoon
authors.affiliation: Department of Orthopaedic, Jeju Halla General Hospital, Jeju, Korea.
authors.forename: Ki-Tae
authors.initials: KT
authors.lastname: Kwon
authors.affiliation: Department of Orthopaedic, Jeju Halla General Hospital, Jeju, Korea.
authors.forename: Sung-Su
authors.initials: SS
authors.lastname: Kim
authors.affiliation: Department of Orthopaedic, Bone Care Orthopaedic Group, Taipei, Taiwan.
authors.forename: Jin-Fu
authors.initials: JF
authors.lastname: Lin
authors.affiliation: Department of Orthopaedic, Dong-In General Hospital, Donghae, Korea.
authors.forename: Bong-Jin
authors.initials: BJ
authors.lastname: Lee
keywords: Adjacent segment; Cervical spine; Congenital; Synostosis