title: Clinical and radiological outcome after anterior cervical discectomy and fusion with stand-alone empty polyetheretherketone (PEEK) cages.
abstract: OBJECTIVE
  To evaluate long-term results after one-, two-, and three-level anterior cervical discectomy and fusion (ACDF) with stand-alone empty polyetheretherketone (PEEK) cages.
  
  
  METHODS
  We performed a retrospective review of a consecutive patient cohort that underwent ACDF with stand-alone empty PEEK cages between 2007 and 2010 with a minimum follow-up of 12 months. Radiographic follow-up included static and flexion/extension radiographs. Changes in the operated segments were measured and compared to radiographs directly after surgery. Clinical outcome was evaluated by a physical examination, pain visual analog scale (VAS), and health-related quality of life (HRQL) using the EuroQOL questionnaire (EQ-5D). Analysis of associations between fusion, subsidence, cervical alignment, and clinical outcome parameters were performed.
  
  
  RESULTS
  Of 407 consecutive cases, 318 met all inclusion criteria. Follow-up data were obtained from 265 (83 %) cases. The mean age at presentation was 55 years and 139 patients were male (52 %). In the sample, 127, 125, and 13 patients had one-, two-, and three-level surgeries, respectively; 132 (49 %) presented with spondylotic cervical myelopathy and 133 (50 %) with cervical radiculopathy. Fusion was achieved in 85, 95, and 94 % of segments in one-, two-, and three-level surgeries, respectively. Non-fusion was associated with higher VAS pain levels. Radiographic adjacent segment disease (ASD) was observed in 20, 29, and 15 % in one-, two-, and three-level surgeries, respectively. ASD was associated with lower HRQL. Subsidence was observed in 25, 27, and 15 % of segments in one-, two-, and three-level surgeries, respectively. However, this had no influence on clinical outcome. Follow-up operations for symptomatic adjacent disc disease and implant failure at index level were needed in 16 (6 %) and four (1.5 %) cases, respectively. Younger age was associated with better clinical outcome. Multilevel surgery favored better myelopathy outcomes and fusion reduced overall pain. ASD worsened EuroQOL-Index values. Worsening of the cervical alignment induced arm pain.
  
  
  CONCLUSIONS
  One- and two-level ACDF with stand-alone empty PEEK cages achieved very high fusion rates and a low rate of follow-up operations. The rate of good clinical outcome is highly satisfactory. Younger age was the single most influential factor associated with better clinical outcome.
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. ehab.shiban@lrz.tum.de.
authors.forename: Ehab
authors.initials: E
authors.lastname: Shiban
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. cary8804@yahoo.de.
authors.forename: Karina
authors.initials: K
authors.lastname: Gapon
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. maria.wostrack@tum.de.
authors.forename: Maria
authors.initials: M
authors.lastname: Wostrack
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. bernhard.meyer@tum.de.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Meyer
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675, Munich, Germany. jens.lehmberg@tum.de.
authors.forename: Jens
authors.initials: J
authors.lastname: Lehmberg
mesh_terms: D000328:Adult; D000368:Aged; D001577:Benzophenones; D002574:Cervical Vertebrae / Q000601:surgery*; D017586:Diskectomy / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D016268:Internal Fixators / Q000009:adverse effects*; D007403:Intervertebral Disc / Q000601:surgery*; D007659:Ketones / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D011092:Polyethylene Glycols / Q000009:adverse effects; D011108:Polymers; D011843:Radiculopathy / Q000601:surgery*; D013123:Spinal Fusion / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*
chemical_list: D001577:Benzophenones; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols
keywords: Anterior cervical discectomy and fusion; Cervical myelopathy; Cervical radiculopathy; PEEK cages; Prognostic factors