title: Cervical Stand-Alone Polyetheretherketone Cage versus Zero-Profile Anchored Spacer in Single-Level Anterior Cervical Discectomy and Fusion : Minimum 2-Year Assessment of Radiographic and Clinical Outcome.
abstract: OBJECTIVE
  We compared the clinical and radiographic outcomes of stand-alone polyetheretherketone (PEEK) cage and Zero-Profile anchored spacer (Zero-P) for single level anterior cervical discectomy and fusion (ACDF).
  
  
  METHODS
  We retrospectively reviewed 121 patients who underwent single level ACDF within 2 years (Jan 2011-Jan 2013) in a single institute. Total 50 patients were included for the analysis who were evaluated more than 2-year follow-up. Twenty-nine patients were allocated to the cage group (m : f=19 : 10) and 21 for Zero-P group (m : f=12 : 9). Clinical (neck disability index, visual analogue scale arm and neck) and radiographic (Cobb angle-segmental and global cervical, disc height, vertebral height) assessments were followed at pre-operative, immediate post-operative, post-3, 6, 12, and 24 month periods.
  
  
  RESULTS
  Demographic features and the clinical outcome showed no difference between two groups. The change between final follow-up (24 months) and immediate post-op of Cobb-segmental angle (p=0.027), disc height (p=0.002), vertebral body height (p=0.033) showed statistically better outcome for the Zero-P group than the cage group, respectively.
  
  
  CONCLUSIONS
  The Zero-Profile anchored spacer has some advantage after cage for maintaining segmental lordosis and lowering subsidence rate after single level anterior cervical discectomy and fusion.
authors.affiliation: Department of Neurosurgery, Korea University Anam Hospital, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Hyun-Jun
authors.initials: HJ
authors.lastname: Cho
authors.affiliation: Department of Neurosurgery, Korea University Anam Hospital, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Junseok W
authors.initials: JW
authors.lastname: Hur
authors.affiliation: Department of Neurosurgery, Korea University Anam Hospital, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Jang-Bo
authors.initials: JB
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Korea University Anam Hospital, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Jin-Sol
authors.initials: JS
authors.lastname: Han
authors.affiliation: Department of Neurosurgery, Korea University Anam Hospital, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Tai-Hyoung
authors.initials: TH
authors.lastname: Cho
authors.affiliation: Department of Neurosurgery, Korea University Anam Hospital, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Jung-Yul
authors.initials: JY
authors.lastname: Park
keywords: Anterior cervical discectomy and fusion; Kyphosis; Stand-alone cage; Subsidence; Zero-profile