Background: The authors' goal was to ascertain regenerate bone-healing metrics using quantitative histomorphometry at a single consolidation period.
Methods: Rats underwent either mandibular distraction osteogenesis (n = 7) or partially reduced fractures (n = 7); their contralateral mandibles were used as controls (n = 11). External fixators were secured and unilateral osteotomies performed, followed by either mandibular distraction osteogenesis (4 days' latency, then 0.3 mm every 12 hours for 8 days; 5.1 mm) or partially reduced fractures (fixed immediately postoperatively; 2.1 mm); both groups underwent 4 weeks of consolidation. After tissue processing, bone volume/tissue volume ratio, osteoid volume/tissue volume ratio, and osteocyte count per high-power field were analyzed by means of quantitative histomorphometry.
Results: Contralateral mandibles had statistically greater bone volume/tissue volume ratio and osteocyte count per high-power field compared with both mandibular distraction osteogenesis and partially reduced fractures by almost 50 percent, whereas osteoid volume/tissue volume ratio was statistically greater in both mandibular distraction osteogenesis specimens and partially reduced fractures compared with contralateral mandibles. No statistical difference in bone volume/tissue volume ratio, osteoid volume/tissue volume ratio, or osteocyte count per high-power field was found between mandibular distraction osteogenesis specimens and partially reduced fractures.
Conclusions: The authors' findings demonstrate significantly decreased bone quantity and maturity in mandibular distraction osteogenesis specimens and partially reduced fractures compared with contralateral mandibles using the clinically analogous protocols. If these results are extrapolated clinically, treatment strategies may require modification to ensure reliable, predictable, and improved outcomes.
Ann Arbor, Mich.; Toledo, Ohio; and Cairo, Egypt
From the University of Michigan Medical School, the University of Toledo, and Ain Shams University.
Received for publication May 10, 2009; accepted February 16, 2010.
Presented in part at the 63rd Annual Meeting of the American Cleft Palate–Craniofacial Association, in Vancouver, British Columbia, Canada, April 3 through 8, 2006, and at the Plastic Surgery Research Council Annual Meeting, in Dana Point, California, May 17 through 20, 2006.
Disclosure: The authors have no commercial association or financial conflicts of interest.
Steven R. Buchman, M.D.; University of Michigan Medical School; 1500 East Medical Center Drive; Mott Children's Hosptal, F7859; Ann Arbor, Mich. 48109-0219; firstname.lastname@example.org