title: Revision surgeries following artificial disc replacement of cervical spine.
abstract: OBJECTIVE
  We investigated causes and results of revision surgeries after artificial disc replacement of cervical spine (C-ADR).
  
  
  METHODS
  Twenty-one patients (mean age: 52.8) who underwent revision surgery after C-ADR and who had a minimum 2-year of follow-up were included into this study. The mean time between the primary and revision surgeries was 21 months. During their primary surgeries, 14 patients underwent single level C-ADR, 2 two-level C-ADR, and 5 two-level hybrid surgery for 16 radiculopathy, 3 myelopathy, and 2 adjacent segment diseases. Causes for revision surgeries were at least one of the followings: 17 poor patient selections, 7 insufficient decompressions, 7 malpositions, 6 subsidences, 3 osteolysis, and 1 postoperative infection.
  
  
  RESULTS
  Sixteen patients underwent anterior removal of C-ADR, one-level discectomy and fusion (N = 11), two-level discectomy (N = 3) or one-level corpectomy (N = 2) and fusion. Three patients of keel type C-ADR with heterotopic ossification underwent posterior laminoforaminotomy and fusion. Two patients underwent combined procedures due to infection or severe subsidence and osteolysis. At the 2-year follow-up, neck (7.3 vs 1.6) and arm (7.0 vs 1.3) visual analog scales and Neck Disability Index score (46.7 vs 16.32) were improved (all, p < 0.05). According to Odom's criteria, 86% of the patients were satisfied and 91% achieved solid fusion. No major complications developed except for transient dysphagia in 6 patients (29%).
  
  
  CONCLUSIONS
  In this small case series, revision surgeries provided successful outcomes in failed C-ADR without major complications. Careful patient selection and meticulous surgical techniques are important to avoid disappointing clinical outcome or even failure of C-ADR.
  
  
  METHODS
  Level IV, Therapeutic study.
authors.affiliation: Department of Orthopedic Surgery, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Republic of Korea. Electronic address: spinepjb@catholic.ac.kr.
authors.forename: Jong-Beom
authors.initials: JB
authors.lastname: Park
authors.affiliation: Department of Orthopedic Surgery, Busan Korea Hospital, Republic of Korea.
authors.forename: Han
authors.initials: H
authors.lastname: Chang
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Republic of Korea.
authors.forename: Jin S
authors.initials: JS
authors.lastname: Yeom
authors.affiliation: Department of Orthopaedic Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Republic of Korea.
authors.forename: Kyung-Soo
authors.initials: KS
authors.lastname: Suk
authors.affiliation: Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Republic of Korea.
authors.forename: Dong-Ho
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Department of Orthopaedic Surgery, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Republic of Korea.
authors.forename: Jae Chul
authors.initials: JC
authors.lastname: Lee
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D017586:Diskectomy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009999:Ossification, Heterotopic / Q000601:surgery; D010147:Pain Measurement; D011183:Postoperative Complications / Q000601:surgery*; D011859:Radiography; D016059:Range of Motion, Articular; D012086:Reoperation / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D013118:Spinal Cord Diseases / Q000601:surgery; D013123:Spinal Fusion / Q000379:methods*; D059145:Total Disc Replacement / Q000009:adverse effects*; D016896:Treatment Outcome
keywords: Artificial disc replacement; Cervical spine; Revision surgeries