title: Erythropoietin augments bone formation in a rabbit posterolateral spinal fusion model.
abstract: We tested the hypothesis that erythropoietin (EPO) enhances bone formation after posterolateral spinal fusion (PLF) in a rabbit model. Thirty-four adult rabbits underwent posterolateral intertransverse arthrodesis at the L5-L6 level using 2.0 g autograft per side. The animals were randomly divided into two groups receiving subcutaneous daily injections of either EPO or saline for 20 days. Treatment commenced 2 days preoperatively. Hemoglobin was monitored at baseline and 2, 4, and 6 weeks after fusion surgery. After euthanasia 6 weeks postoperatively, manual palpation, radiographic, and histomorphometric examinations were performed. Bone volume of the fusion mass was estimated by CT after 6 weeks. EPO increased bone fusion volume to 3.85 ccm (3.66-4.05) compared with 3.26 ccm (2.97-3.55) in the control group (p<0.01). EPO treatment improved vascularization of the fusion mass and increased hemoglobin levels (p<0.01). Fusion rate tended to be higher in the EPO group based on manual palpation, CT, and radiographic examinations. For the first time EPO has shown to augment bone formation after autograft PLF in a rabbit model. Increased vascularization provides a partial explanation for the efficacy of EPO as a bone autograft enhancer.
authors.affiliation: Orthopaedic Research Laboratory, Aarhus University Hospital, Aarhus, Denmark. jan.roelfing@ki.au.dk
authors.forename: Jan Hendrik Duedal
authors.initials: JH
authors.lastname: Rölfing
authors.forename: Michael
authors.initials: M
authors.lastname: Bendtsen
authors.forename: Jonas
authors.initials: J
authors.lastname: Jensen
authors.forename: Maik
authors.initials: M
authors.lastname: Stiehler
authors.forename: Casper Bindzus
authors.initials: CB
authors.lastname: Foldager
authors.forename: Michel Bach
authors.initials: MB
authors.lastname: Hellfritzsch
authors.forename: Cody
authors.initials: C
authors.lastname: Bünger
mesh_terms: D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects*; D016025:Bone Transplantation; D004921:Erythropoietin / Q000494:pharmacology*; D006454:Hemoglobins / Q000378:metabolism; D007085:Ilium / Q000637:transplantation; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000601:surgery*; D008297:Male; D023421:Models, Animal; D018919:Neovascularization, Physiologic / Q000187:drug effects; D011817:Rabbits; D013123:Spinal Fusion; D055114:X-Ray Microtomography
chemical_list: D006454:Hemoglobins; D004921:Erythropoietin