title: Preliminary results in anterior cervical discectomy and fusion with an experimental bioabsorbable cage - clinical and radiological findings in an ovine animal model.
abstract: BACKGROUND
  Bioabsorbable implants are not widely used in spine surgery. This study investigated the clinical and radiological findings after anterior cervical discectomy and fusion (ACDF) in an ovine animal model with an experimental bioabsorbable cage consisting of magnesium and polymer (poly-ϵ-caprolactone, PCL) in comparison to a tricortical bone graft as the gold standard procedure.
  
  
  METHODS
  24 full-grown sheep had ACDF of C3/4 and C5/6 with an experimental bioabsorbable implant (magnesium and PCL) in one level and an autologous tricortical bone graft in the second level. The sheep were divided into 4 groups (6 sheep each). After 3, 6, 12, or 24 weeks postoperatively, the cervical spines were harvested and conventional x-rays of each operated segment were conducted. The progress of interbody fusion was classified according to a three-point scoring system.
  
  
  RESULTS
  There were no operation related complications except for one intraoperative fracture of the anterior superior iliac spine and two cases of screw loosening and sinking, respectively. In particular, no vascular, neurologic, wound healing or infectious problems were observed. According to the time of follow-up, both interbody fusion devices showed similar behaviour with increasing intervertebral osseointegration and complete arthrodesis in 10 of 12 (83.3%) motion segments after 24 weeks.
  
  
  CONCLUSIONS
  The bioabsorbable magnesium-PCL cage used in this experimental animal study showed clinically no signs of incompatibility such as infectious or wound healing problems. The radiographic results regarding the osseointegration are comparable between the cage and the bone graft group.
authors.affiliation: Orthopedic Department of Hannover Medical School, Diakoniekrankenhaus Annastift gGmbH, Anna-von-Borries-Str. 1-7, 30625 Hannover, Germany.
authors.forename: Dorothea
authors.initials: D
authors.lastname: Daentzer
authors.forename: Thilo
authors.initials: T
authors.lastname: Floerkemeier
authors.forename: Ivonne
authors.initials: I
authors.lastname: Bartsch
authors.forename: Waseem
authors.initials: W
authors.lastname: Masalha
authors.forename: Bastian
authors.initials: B
authors.lastname: Welke
authors.forename: Christof
authors.initials: C
authors.lastname: Hurschler
authors.forename: Theresa
authors.initials: T
authors.lastname: Kauth
authors.forename: Daniel
authors.initials: D
authors.lastname: Kaltbeitzel
authors.forename: Christian
authors.initials: C
authors.lastname: Hopmann
authors.forename: Bernd
authors.initials: B
authors.lastname: Kujat
authors.forename: Katharina
authors.initials: K
authors.lastname: Kalla
keywords: ACDF; Animal model; Bioabsorbable cage; Cervical spine; Fusion; Magnesium; Ovine animal model; Poly-ϵ-caprolactone; Polymer; Sheep
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