title: The Correlation between Insertion Depth of Prodisc-C Artificial Disc and Postoperative Kyphotic Deformity: Clinical Importance of Insertion Depth of Artificial Disc.
abstract: OBJECTIVE
  This study was designed to investigate the correlation between insertion depth of artificial disc and postoperative kyphotic deformity after Prodisc-C total disc replacement surgery, and the range of artificial disc insertion depth which is effective in preventing postoperative whole cervical or segmental kyphotic deformity.
  
  
  METHODS
  A retrospective radiological analysis was performed in 50 patients who had undergone single level total disc replacement surgery. Records were reviewed to obtain demographic data. Preoperative and postoperative radiographs were assessed to determine C2-7 Cobb's angle and segmental angle and to investigate postoperative kyphotic deformity. A formula was introduced to calculate insertion depth of Prodisc-C artificial disc. Statistical analysis was performed to search the correlation between insertion depth of Prodisc-C artificial disc and postoperative kyphotic deformity, and to estimate insertion depth of Prodisc-C artificial disc to prevent postoperative kyphotic deformity.
  
  
  RESULTS
  In this study no significant statistical correlation was observed between insertion depth of Prodisc-C artificial disc and postoperative kyphotic deformity regarding C2-7 Cobb's angle. Statistical correlation between insertion depth of Prodisc-C artificial disc and postoperative kyphotic deformity was observed regarding segmental angle (p<0.05). It failed to estimate proper insertion depth of Prodisc-C artificial disc effective in preventing postoperative kyphotic deformity.
  
  
  CONCLUSIONS
  Postoperative segmental kyphotic deformity is associated with insertion depth of Prodisc-C artificial disc. Anterior located artificial disc leads to lordotic segmental angle and posterior located artificial disc leads to kyphotic segmental angle postoperatively. But C2-7 Cobb's angle is not affected by artificial disc location after the surgery.
authors.affiliation: Department of Neurosurgery, Korea University College of Medicine, Seoul, Korea.
authors.forename: Do-Youl
authors.initials: DY
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Korea University College of Medicine, Seoul, Korea.
authors.forename: Se-Hoon
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Korea University College of Medicine, Seoul, Korea.
authors.forename: Jung-Keun
authors.initials: JK
authors.lastname: Suh
authors.affiliation: Department of Neurosurgery, Korea University College of Medicine, Seoul, Korea.
authors.forename: Tai-Hyoung
authors.initials: TH
authors.lastname: Cho
authors.affiliation: Department of Neurosurgery, Korea University College of Medicine, Seoul, Korea.
authors.forename: Yong-Gu
authors.initials: YG
authors.lastname: Chung
keywords: Insertion depth; Postoperative kyphotic deformity; Prodisc-C artificial disc; Total disc replacement