title: Novel model of calvarial defect in an infected unfavorable wound: reconstruction with rhBMP-2. Part II.
abstract: BACKGROUND
  Animal models of bone reconstruction have shown recombinant human bone morphogenetic protein 2 (rhBMP-2) to be an effective therapy in the acute calvarial defect wound. The purpose of this study was to compare the effectiveness of rhBMP-2 in a rabbit model of an unfavorable scarred calvarial wound with the criterion standard of autograft.
  
  
  METHODS
  Nineteen adult New Zealand white rabbits underwent subtotal calvariectomy. After 6 weeks of healing and normal scar formation, these animals underwent reoperation for scar debridement and assignment to 1 of 4 therapeutic groups. Animals were assigned to an empty control group (no treatment, n = 3), vehicle control group (neutral buffered solution on an absorbable collagen sponge [ACS], n = 3), surgical control group (cryopreserved autograft, n = 3), or an experimental treatment group (rhBMP-2 on an ACS, n = 10). All animals underwent computed tomography imaging at 0, 2, 4, and 6 weeks after secondary reconstructive surgery. At 6 weeks, all animals were killed, and the defects were examined histologically. Percentage of healing of each defect was determined, and a 4 × 3 mixed-model analysis of variance was performed on healing as a function of time and therapy.
  
  
  RESULTS
  Based on measures of defect radiopacity, the treatment group (rhBMP-2/ACS) and surgical control group (autograft) were statistically equivalent with 98% and 83% healing, respectively, at 6 weeks. The empty control and vehicle control groups were inferior to the treatment group (rhBMP-2/ACS) and surgical control (autograft) groups at each timepoint (P < 0.05). Histologically, bone in the surgical control (autograft) group was less trabecular and less cellular than the bone formed in the experimental treatment group (rhBMP-2/ACS).
  
  
  CONCLUSIONS
  Compared with historical controls, rhBMP-2 therapy was as effective in reconstructing calvarial defects in the unfavorable scarred wound as in the acute favorable calvarial wound. When compared with cryopreserved autograft, rhBMP-2-regenerated bone showed equal defect coverage and similar bone thickness with varying bony architecture.
authors.affiliation: Division of Plastic Surgery, University of Pittsburgh, Pittsburgh, PA 15201, USA.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Kinsella
authors.forename: James J
authors.initials: JJ
authors.lastname: Cray
authors.forename: Darren M
authors.initials: DM
authors.lastname: Smith
authors.forename: S Alex
authors.initials: SA
authors.lastname: Rottgers
authors.forename: Mark P
authors.initials: MP
authors.lastname: Mooney
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Cooper
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Losee
mesh_terms: D020341:Absorbable Implants; D000704:Analysis of Variance; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology*; D003094:Collagen; D003646:Debridement; D004195:Disease Models, Animal; D008297:Male; D011817:Rabbits; D011994:Recombinant Proteins / Q000494:pharmacology; D012886:Skull / Q000601:surgery* / Q000637:transplantation; D013530:Surgical Wound Infection / Q000188:drug therapy* / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014182:Transplantation, Autologous; D014945:Wound Healing / Q000187:drug effects
chemical_list: D055396:Bone Morphogenetic Protein 2; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D003094:Collagen