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NOVEL ANIMAL MODEL OF CALVARIAL DEFECT PART IV: Reconstruction of a Calvarial Wound Complicated by Durectomy
Zoe M. MacIsaac, MD, James J. Cray, PhD, Darren M. Smith, MD1, Benjamin A.Levine, Mark M. Mooney, PhD, Christopher R. Kinsella, Jr., MD, Gregory M. Cooper, PhD, Joseph E. Losee, MD.
University of Pittsburgh
2012-02-15
Presenter: Zoe M. MacIsaac
Affidavit:
The abstract has not been published or presented at a major meeting and represents the work of the research fellow.
Director Name: Joseph Losee, MD
Author Category: Student
Presentation Category: Basic Science Research
Abstract Category: Craniomaxillofacial
How does this presentation meet the established conference educational objectives?
Craniofacial defects pose a longstanding problem for plastic and reconstructive surgeons. Although the current gold standard, autologous graft, may be employed, this introduces donor site morbidity and other complications such as graft loss, while implant-based approaches introduce risk of extrusion and increased risk of infection. Current concepts in craniofacial reconstruction will be reviewed, and the standard of autologous repair will be compared with reconstruction using rhBMP-2/ACS.
How will your presentation be used by practicing physicians in the audience?
The audience will evaluate the efficacy of BMP-2 therapy for bone regeneration in unfavorable calvarial wounds complicated by durectomy, and compare rhBMP-2/ACS treatment to the current gold standard, autologous repair.
BACKGROUND:
Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been shown to be an effective therapy in the acute calvarial defect wound and in calvarial defects complicated by chronic scar and radiation. The aim of this study was to assess the effectiveness of rhBMP-2-mediated bone regeneration in calvarial defects complicated by durectomy.
METHODS:
Sixteen adult New Zealand white rabbits underwent subtotal calvariectomy and dural removal, followed by dural repair and reconstruction in one of four groups: empty (n=3), vehicle (buffer solution on absorbable collagen sponge (ACS), n=2), autologous graft (n=3), or rhBMP-2 repair (rhBMP-2/ACS, n=8). Animals underwent CT imaging at 0, 2, 4 and 6 weeks postoperatively, followed by euthanization and histological analysis. Percent healing was determined by 3-dimensional analysis. A 4x3 mixed model ANOVA was performed on healing versus treatment group/postoperative time.
RESULTS:
Based on measures of radiopacity, rhBMP-2/ACS and autograft resulted in 51.4% and 37.3% healing respectively, while the empty and vehicle control groups resulted in 7.8% and 17.9% healing at six weeks, without statistical significance. Compared to immediate favorable reconstruction (96.8% healing), rhBMP-2 in this setting was significantly less effective (p=0.001). Histologically, bone in the rhBMP-2/ACS group was compact and cellular but appeared only over the intact sagittal sinus and irregularly within the ACS.
CONCLUSIONS:
Although promising in the acute calvarial wound and other complex defects, rhBMP-2 therapy is less effective in reconstruction in the face of dural compromise. Future studies may employ manipulations such as additional growth factors/cell therapy to improve results in this especially difficult scenario.
