Extracorporeal shock wave accelerates consolidation in distraction osteogenesis of the rat mandible.
BACKGROUND
One of major limitations of applying distraction osteogenesis for craniofacial skeleton hypoplasia is the long duration for bony consolidation. This study investigated whether extracorporeal shock wave therapy (ESWT) could accelerate bony consolidation in distraction osteogenesis of the rat mandible.


METHODS
An L-shape osteotomy was performed unilaterally in the hemimandible of Sprague-Dawley rats. An internal distracter was employed to create a 7-mm distraction gap in the mandible. One hundred twenty rats were divided into three groups. The distraction zone of the mandible was received no treatment as controls (group I). Group II received ESWT (500 impulses at 14 kV) at 2 weeks postoperatively. Group III treated with 500 ESW impulses at 21 kV at 2 weeks postoperatively.


RESULTS
Dual-energy X-ray absorptiometry and material testing showed that optimal dosage of ESWT in group II significantly increased mineral density and enhanced biomechanical strength of the bone tissue. In histomorphological analysis, the mandibular tissue in group II showed intense osteoblastic cell recruitment, new bone formation, and vascularization. The osteoblasts in the distracted zone in group II indicated significantly strong immunoreactivities for proliferating cell nuclear antigen, vascular endothelial growth factor, and bone morphogenetic protein-2, when compared with other groups.


CONCLUSIONS
Optimal dosage of ESWT was beneficial for accelerating facial skeleton consolidation and bone regeneration in the distracted rat mandible tissue. The mechanism was presumably associated with the up-regulation of neovascularization, cell proliferation, and osteogenic growth factor expression in bone microenvironment.
Lai
Jui-Pin
JP
Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
Wang
Feng-Sheng
FS
Hung
Chun-Min
CM
Wang
Ching-Jen
CJ
Huang
Chun-Jen
CJ
Kuo
Yur-Ren
YR
D015502:Absorptiometry, Photon; D000818:Animals; D015519:Bone Density; D001861:Bone Regeneration; D004195:Disease Models, Animal; D019220:High-Energy Shock Waves; D008297:Male; D008334:Mandible / Q000473:pathology / Q000528:radiation effects* / Q000601:surgery; D008337:Mandibular Fractures / Q000473:pathology / Q000628:therapy*; D010012:Osteogenesis / Q000528:radiation effects*; D019857:Osteogenesis, Distraction / Q000379:methods*; D010027:Osteotomy; D051381:Rats; D017207:Rats, Sprague-Dawley