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: Christopher R Kinsella Jr, James J Cray, Darren M Smith, S Alex Rottgers, Mark P Mooney, Gregory M Cooper, Joseph E Losee
• Journal: The Journal of craniofacial surgery (J Craniofac Surg) Vol. 23 Issue 2 Pg. 410-4 (Mar 2012) ISSN: 1536-3732 [Electronic] United States
• PMID: 22421834 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Bone Morphogenetic Protein 2
• Recombinant Proteins
• Transforming Growth Factor beta
• recombinant human bone morphogenetic protein-2
• Collagen

Topics

• Absorbable Implants
• Analysis of Variance
• Animals
• Bone Morphogenetic Protein 2 (pharmacology)
• Collagen
• Debridement
• Disease Models, Animal
• Male
• Rabbits
• Recombinant Proteins (pharmacology)
• Skull (surgery, transplantation)
• Surgical Wound Infection (drug therapy, surgery)
• Tomography, X-Ray Computed
• Transforming Growth Factor beta (pharmacology)
• Transplantation, Autologous
• Wound Healing (drug effects)