title: PEEK cages versus PMMA spacers in anterior cervical discectomy: comparison of fusion, subsidence, sagittal alignment, and clinical outcome with a minimum 1-year follow-up.
abstract: OBJECTIVE
  To compare radiographic and clinical outcomes after anterior cervical discectomy in patients with cervical degenerative disc disease using PEEK cages or PMMA spacers with a minimum 1-year follow-up.
  
  
  METHODS
  Anterior cervical discectomy was performed in 107 patients in one or two levels using empty PEEK cages (51 levels), Sulcem PMMA spacers (49 levels) or Palacos PMMA spacers (41 levels) between January, 2005 and February, 2009. Bony fusion, subsidence, and sagittal alignment were retrospectively assessed in CT scans and radiographs at follow-up. Clinical outcome was measured using the VAS, NDI, and SF-36.
  
  
  RESULTS
  Bony fusion was assessed in 65% (PEEK cage), 57% (Sulcem), and 46% (Palacos) after a mean follow-up of 2.5 years. Mean subsidence was 2.3-2.6 mm without significant differences between the groups. The most pronounced loss of lordosis was found in PEEK cages (-4.1°). VAS was 3.1 (PEEK cage), 3.6 (Sulcem), and 2.7 (Palacos) without significant differences. Functional outcome in the PEEK cage and Palacos group was superior to the Sulcem group.
  
  
  CONCLUSIONS
  The substitute groups showed differing fusion rates. Clinical outcome, however, appears to be generally not correlated with fusion status or subsidence. We could not specify a superior disc substitute for anterior cervical discectomy. This trial is registered with DRKS00003591.
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, 79106 Freiburg, Germany.
authors.forename: Jan-Helge
authors.identifier: 0000-0003-3469-9027
authors.initials: JH
authors.lastname: Klingler
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, 79106 Freiburg, Germany.
authors.forename: Marie T
authors.initials: MT
authors.lastname: Krüger
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, 79106 Freiburg, Germany.
authors.forename: Ronen
authors.initials: R
authors.lastname: Sircar
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, 79106 Freiburg, Germany.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Kogias
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, 79106 Freiburg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Scholz
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, 79106 Freiburg, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Volz
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, 79106 Freiburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Scheiwe
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, 79106 Freiburg, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hubbe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001577:Benzophenones; D002574:Cervical Vertebrae; D017586:Diskectomy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007403:Intervertebral Disc / Q000601:surgery*; D055959:Intervertebral Disc Degeneration / Q000175:diagnosis / Q000628:therapy; D007659:Ketones; D008297:Male; D008875:Middle Aged; D011092:Polyethylene Glycols; D011108:Polymers; D019904:Polymethyl Methacrylate; D011182:Postoperative Care; D019233:Retreatment; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D001577:Benzophenones; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols; D019904:Polymethyl Methacrylate
references.citation: Spine J. 2004 Mar-Apr;4(2):184-91; discussion 191
references.pmid: 15016396
references.citation: BMC Musculoskelet Disord. 2012 Sep 14;13:172
references.pmid: 22978810
references.citation: Neurosurgery. 2002 Dec;51(6):1343-49; discussion 1349-50
references.pmid: 12445338
references.citation: J Neurosurg. 2000 Oct;93(2 Suppl):222-6
references.pmid: 11012052
references.citation: Spine (Phila Pa 1976). 2011 Jun 15;36(14):E950-60
references.pmid: 21522044
references.citation: Neurosurg Rev. 2004 Jan;27(1):34-41
references.pmid: 12905078
references.citation: J Orthop Traumatol. 2011 Dec;12(4):201-5
references.pmid: 22089645
references.citation: Clin Orthop Surg. 2011 Mar;3(1):16-23
references.pmid: 21369474
references.citation: Neurosurg Focus. 2002 Jan 15;12(1):E4
references.pmid: 16212331
references.citation: J Neurosurg Spine. 2005 Jul;3(1):24-8
references.pmid: 16122018
references.citation: Cochrane Database Syst Rev. 2011 Jan 19;(1):CD004958
references.pmid: 21249667
references.citation: J Neurosurg Spine. 2006 Jun;4(6):447-53
references.pmid: 16776355
references.citation: Spine (Phila Pa 1976). 1996 Mar 15;21(6):741-9
references.pmid: 8882698
references.citation: Neurosurg Rev. 2009 Apr;32(2):207-14; discussion 214
references.pmid: 18797946
references.citation: Zentralbl Neurochir. 2001;62(4):200-2
references.pmid: 12023757
references.citation: Neurosurg Rev. 1989;12(3):217-21
references.pmid: 2812353
references.citation: Spine (Phila Pa 1976). 2008 Nov 1;33(23):2524-428
references.pmid: 18978593
references.citation: Eur Spine J. 2008 Mar;17(3):432-438
references.pmid: 18193299
references.citation: Eur Spine J. 2009 Feb;18(2):238-43
references.pmid: 19130094
references.citation: Acta Neurochir (Wien). 2011 Mar;153(3):559-65
references.pmid: 21132445
references.citation: Zentralbl Neurochir. 2007 Feb;68(1):2-7
references.pmid: 16969747
references.citation: Eur Spine J. 2003 Oct;12(5):513-6
references.pmid: 12827473
references.citation: Spine (Phila Pa 1976). 1996 Apr 1;21(7):834-9; discussion 840
references.pmid: 8779014
references.citation: Spine (Phila Pa 1976). 2001 Nov 15;26(22):2463-6
references.pmid: 11707711
references.citation: Spine (Phila Pa 1976). 2000 Nov 1;25(21):2762-70
references.pmid: 11064521
references.citation: Eur Spine J. 2012 Jul;21(7):1374-82
references.pmid: 22205113
references.citation: Acta Neurochir (Wien). 2006 Mar;148(3):307-12; discussion 312
references.pmid: 16341633
references.citation: J Spinal Disord Tech. 2010 Jul;23(5):310-6
references.pmid: 20124907
references.citation: Spine (Phila Pa 1976). 2006 May 15;31(11):1207-14; discussion 1215-6
references.pmid: 16688033
references.citation: PLoS One. 2012;7(8):e43407
references.pmid: 22912869
references.citation: Cent Eur Neurosurg. 2009 Nov;70(4):180-6
references.pmid: 19722129
references.citation: Spine (Phila Pa 1976). 2011 Jan 1;36(1):15-20
references.pmid: 20562731
references.citation: Int Orthop. 2008 Oct;32(5):643-8
references.pmid: 17639386
references.citation: J Neurosurg. 2001 Jul;95(1 Suppl):40-2
references.pmid: 11453429
references.citation: J Clin Neurosci. 2008 Nov;15(11):1240-5
references.pmid: 18801658
references.citation: BMC Musculoskelet Disord. 2011 Jun 28;12:140
references.pmid: 21711527
references.citation: J Neurosurg. 2003 Mar;98(2 Suppl):143-8
references.pmid: 12650398
references.citation: J Clin Neurosci. 2007 Aug;14(8):723-8
references.pmid: 17543528
references.citation: J Neurosurg Spine. 2006 Apr;4(4):292-9
references.pmid: 16619675
references.citation: Spine J. 2007 Mar-Apr;7(2):205-9
references.pmid: 17321970
references.citation: Spine (Phila Pa 1976). 2001 Feb 1;26(3):249-55
references.pmid: 11224860