Quality and Quantity Analysis of rhBMP-2 and Iliac Crest Alveolar Cleft Bone Grafting With Cortical Strut Technique

Quality and quantity analysis of bone grafting alveolar cleft defects with a cortical strut technique have not been described. A retrospective case series of n=25 alveolar clefts, 22 subjects, from April 2011 to July 2013 met University of Nebraska Medical Center’s inclusion criteria and International Board Review approval. Inclusion criteria included use of a newly described cortical strut technique for alveolar cleft bone grafting performed with recombinant human Bone Morphogenetic Protein-2 (rhBMP-2) with human cortical bone allograft  (n=11) or cortical and cancellous anterior iliac crest bone (n=14) grafting materials.  Subjects underwent preoperative and 6 month postoperative multi-slice cone beam computed tomography. Additionally, subjects were followed 1-2 weeks and 3-6 months postoperatively. One subject did not meet inclusion criteria and was excluded from the study. Volumetric measurements were performed on preoperative and 6 month postoperative multi-slice cone beam computed tomography. Measurements were obtained in the anterior-posterior, vertical and mesial-distal dimensions from which volume was calculated. Density of bone graft incorporation was analyzed in Hounsfield units (HU) averaged over the entire volume of a successful bone graft on the 6 month multi-slice cone beam computed tomography. Measurements were acquired and verified by triplet measurement at three different points in time by an Oral and Maxillofacial Radiologist, who was blinded to the category of bone graft material used.  Results revealed 84.0% volumetric fill for anterior iliac crest graft versus 79.3% (86.5% for primary grafts and 76.4% for repeat grafts) volumetric fill for rhBMP-2, which were not statistically different (P=0.37). HU analysis revealed no statistical difference (P=0.37) with 366.1 for anterior iliac crest graft versus 401.0 (467.4 for primary grafts and 267.5 for repeat grafts) for rhBMP-2. Fistula formation occurred with resultant failure of 5 grafts, 1 for anterior iliac crest and 4 for rhBMP-2, and traumatic accident resulted in failure of 1 anterior iliac crest bone graft. A concurrent study by University of Nebraska Medical Center has revealed a 50% decrease in fistula formation with the utilization of the newly described cortical strut technique. Successful quality and quantity of alveolar cleft bone grafting is achieved with both rhBMP-2 and iliac crest bone-grafting materials using the cortical strut technique.

References:

Canan, LW and et al. Human bone morphogenetic protein-2 use for maxillary reconstruction in cleft lip and palate patients. Journal of Craniofacial Surgery (2012), 23(6): 1627 – 1633.

Silva, IM and et al. Bone Density: Comparative evaluation of Hounsfield units in multislice and cone beam computed tomography. Oral Radiology (2012), 26(6): 550 – 556.