title: Significant relationship between local angle at fused segments and C2-7 angle: Average duration of longer than 20 years after anterior cervical discectomy and fusion.
abstract: BACKGROUND
  The authors have focused their attention to the radiological durability of cervical sagittal alignment after anterior cervical discectomy and fusion (ACDF) using autologous bone grafting.
  
  
  METHODS
  Among the patients who underwent ACDF with trans-unco-discal (TUD) approach between 1976 and 1997, 22 patients (16 males and 6 females) made return visits for a clinical evaluation. Patients with trauma or previously treated by anterior cervical fusion or by posterior decompression were excluded from the present study. Clinical evaluation included adjacent segment degeneration (ASD), osseous fusion, local angle at the fused segments and C2-7 angle of cervical spine.
  
  
  RESULTS
  The duration after ACDF ranged from 13 to 34 years with an average of 21.3 ± 7.0 years. A single level fusion was done on 8 patients, 2 levels on 11 patients, 3 levels on 2 patients, and 4 levels on 1 patient. Imaging studies indicated that 12 of the 22 patients (54.5%) were graded as having symptomatic ASD. Osseous bony fusion at ACDF was recognized in all cases. None of the patients demonstrated kyphotic malalignment of the cervical spine. Average degrees of local angle at the fused segments and the C2-7 angle were 7.06 and 17.6, respectively. Statistical analysis indicated a significant relationship between the local at the fused segments and C2-7 angles.
  
  
  CONCLUSIONS
  Sagittal alignment of the cervical spine was durable long after ACDF when the local angle at the fused segments was well stabilized.
authors.affiliation: Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nagata
authors.forename: T
authors.initials: T
authors.lastname: Takami
authors.forename: T
authors.initials: T
authors.lastname: Yamagata
authors.forename: T
authors.initials: T
authors.lastname: Uda
authors.forename: K
authors.initials: K
authors.lastname: Naito
authors.forename: K
authors.initials: K
authors.lastname: Ohata
keywords: Anterior cervical; cervical alignment; interbody fusion; local angle; trans-unco-discal approach