Vertical distraction osteogenesis in the human mandible: a prospective morphometric study

Abstract

Vertical distraction osteogenesis has received considerable interest as a way to augment bone prior to implant placement. However, very little is known regarding the appropriate distraction protocols in the human mandible. In this study, we evaluate the effect of the distraction rate and the duration of neutrofixation on bone formation and closure of the gap in the human mandible. Vertical distraction was performed in the atrophic mandible of 16 edentulous patients, aged 62+/-6 years. The bone was distracted for approximately 10 mm at a rate of either 0.5 or 1 mm/day. Bone biopsies were taken after 7-20 weeks of neutrofixation. Histological analysis demonstrated newly formed bone in the distraction gap in all biopsies. The bone was predominantly of the woven type. After 10 weeks of neutrofixation, the gap was bridged by new bone in two out of three intact samples in the 0.5 mm/day group, but not in two intact samples of the 1 mm/day group. Histomorphometry revealed longer bone trabeculae (P=0.02) and a somewhat increased bone volume in the area where new bone formation started (P=0.07) in the group of patients having the 0.5 mm/day of distraction rate than in the 1 mm/day group. We conclude that in elderly patients, a distraction rate of 0.5 mm/day results in faster osteogenesis in the distraction gap than a rate of 1 mm/day. A minimum of 10 weeks of neutrofixation seems to be needed to close a 10 mm gap after cessation of distraction.

Immunolocalization of Sibling and RUNX2 Proteins During Vertical Distraction Osteogenesis in the Human Mandible

“…One could argue that cartilage was present only initially but disappeared by remodeling (Sato et al 1998). Because we could not find any cartilage remnants in the gap area after staining with safranin-O and toluidine blue either in the present or previous study (Amir et al 2006a) and because bone remodeling in human is relatively slow, it is likely that the trabeculae were formed intramembranously, as happens during embryonic development of jawbone.…”

“…data showing that four times as much osteoid is present in old, atrophic human bone after distraction than before distraction (Amir et al 2006a). After loading, some of the mature osteocytes embedded in the old lamellar bone were also positive for DMP1 and MEPE, an observation not seen in the samples taken before distraction.…”

“…Patient selection and surgical procedures have been described in detail (Amir et al 2006a). Briefly, 10 edentulous patients (between 52 and 74 years of age) with severely atrophic mandibles (z8-mm residual height) underwent anterior alveolar bone augmentation by vertical distraction osteogenesis using extraosseous distractors (KLS Martin and Mondeal Medical Systems; Tuttlingen, Germany).…”

“…Briefly, 10 edentulous patients (between 52 and 74 years of age) with severely atrophic mandibles (z8-mm residual height) underwent anterior alveolar bone augmentation by vertical distraction osteogenesis using extraosseous distractors (KLS Martin and Mondeal Medical Systems; Tuttlingen, Germany). Predistraction bone biopsies were taken from two patients to compare with postdistraction bone (see Amir et al 2006a). After performing an osteotomy and placing the distractor, a latency period of 5-7 days was introduced to enable callus formation.…”

“…We previously showed that human mandibular bone that undergoes mechanical loading by distraction formed substantially more osteoid than undistracted bone (Amir et al 2006a). This suggested that, by distraction, cells along or near the bone surface become activated to deposit new layers of bone against existing bone.…”