title: Cervical disc replacement in patients with and without previous adjacent level fusion surgery: a prospective study.
abstract: METHODS
  Prospective 6-center study. OBJECTIVE.: To evaluate outcomes of cervical disc replacement performed adjacent to a prior cervical fusion.
  
  
  BACKGROUND
  The use of disc replacement adjacent to a prior anterior cervical decompression and fusion (ACDF) is an attractive reconstructive option, obviating the need for a multilevel fusion. This study reports outcomes from patients with and without previous ACDF receiving the porous coated motion (PCM) artificial cervical disc in a United States Federal Drug Administration Investigational Device Exemption trials.
  
  
  METHODS
  Patients between ages of 18 and 65 with single-level cervical radiculopathy and/or myelopathy, unresponsive to at least 6 weeks of nonsurgical therapy, or experiencing progressive neurologic symptoms were enrolled. Clinical outcomes are compared for patients receiving a PCM disc at a level adjacent to a prior ACDF ("adjacent") and those without having previously had fusion ("primary").
  
  
  RESULTS
  126 PCM patients were primary (mean age: 44.4 years.) and 26 patients had previous "adjacent level" fusion surgery (mean age: 46.4 years). Surgery time was similar in both groups (96 minutes and 98 minutes, respectively; P = 0.761), and mean blood loss was 76 mL and 66 mL in the 2 groups, respectively (P = 0.491). Clinical outcomes using Neck Disability Index and Visual Analog Scores neck and arm scores showed significant improvement after surgery and were similar between groups at all time points. Revision surgery occurred in 2 of 126 primary patients, and in 2 of 26 patients in the adjacent-to-fusion group.
  
  
  CONCLUSIONS
  Although the level adjacent to a prior cervical fusion is subject to increased biomechanical forces, potentially leading to a higher risk of failure, the PCM disc was well tolerated in the short term. The early clinical results of disc replacement adjacent to a prior fusion are good and comparable to the outcomes after primary disc replacement surgery. However, in view of the small study population and short-term follow-up, continued study is mandatory.
authors.affiliation: Rush University Medical Center, Chicago, IL 60612, USA. frank.phillips@rushortho.com
authors.forename: Frank M
authors.initials: FM
authors.lastname: Phillips
authors.forename: Todd R
authors.initials: TR
authors.lastname: Allen
authors.forename: John J
authors.initials: JJ
authors.lastname: Regan
authors.forename: Todd J
authors.initials: TJ
authors.lastname: Albert
authors.forename: Andrew
authors.initials: A
authors.lastname: Cappuccino
authors.forename: John G
authors.initials: JG
authors.lastname: Devine
authors.forename: Jeanette E
authors.initials: JE
authors.lastname: Ahrens
authors.forename: John A
authors.initials: JA
authors.lastname: Hipp
authors.forename: Paul C
authors.initials: PC
authors.lastname: McAfee
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D002858:Chromium Alloys; D004185:Disability Evaluation; D017586:Diskectomy / Q000009:adverse effects / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D020959:Polyethylene; D011446:Prospective Studies; D019736:Prostheses and Implants; D011474:Prosthesis Design; D011843:Radiculopathy / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery; D011859:Radiography; D012086:Reoperation / Q000379:methods; D013118:Spinal Cord Diseases / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery; D013123:Spinal Fusion / Q000009:adverse effects / Q000379:methods*
chemical_list: D002858:Chromium Alloys; D020959:Polyethylene