Role of guided bone regeneration principle in preventing fibrous healing in distraction osteogenesis at high speed: experimental study in rabbit mandibles.

The formation of fibrous tissues at the distraction gap may result from the accumulation of rapidly migrating fibroblasts at the site of an osteotomy, especially when distraction is rapid. Addition of osteopromotive membranes could theoretically prevent fibroblasts from entering the distraction gap, allowing the osteotomy site to be filled with only osteogenic cells. This study is an attempt to achieve a rapid successful distraction without fibrosis through the use of collagen membranes. Sixteen skeletally mature New Zealand white rabbits were used in this study. They were divided into two groups. One rabbit from each group was excluded from the study because of dislodgement of the distractors. In one group (n = 7), distraction was done as usual. In the other group (n = 7), a collagen membrane surrounded the osteotomy site to be distracted. After a 7-day latency period, distraction started at a rate 2 mm once per day for 5 days. The distractor was left in place for 4 weeks to allow consolidation. Results showed osteogenesis in both groups. Whereas addition of the membrane to distraction increased the quantity of bone formed, absence of the membrane allowed early mineralization (better quality of bone regarding the density). Neither of the two groups showed significant fibrosis or cartilage formation. The endosteum served as a source of blood supply when the periosteum was excluded. The periosteum served as a membrane for guided bone regeneration. Membranes for guided bone regeneration can be used with distraction when the periosteum is lost from trauma or is broken from fast distraction.