Ultrasound Produced by a Conventional Therapeutic Ultrasound Unit Accelerates Fracture Repair

Abstract

Background and Purpose. A recent novel application of ultrasound therapy is the treatment of bone fractures. The aim of this study was to investigate the effect on fracture repair of ultrasound produced by a conventional therapeutic ultrasound unit as used by physical therapists. Subjects and Methods. Bilateral midshaft femur fractures were created in 30 adult male Long-Evans rats. Ultrasound therapy was commenced on the first day after fracture and introduced 5 days a week for 20 minutes a day. Each animal was treated unilaterally with active ultrasound and contralaterally with inactive ultrasound. Active ultrasound involved a 2-millisecond burst of 1.0-MHz sine waves repeating at 100 Hz. The spatially averaged, temporally averaged intensity was set at 0.1 W/cm 2 . Animals were killed at 25 and 40 days after fracture induction, and the fractures were assessed for bone mass and strength. Results. There were no differences between fractures treated with active ultrasound and fractures treated with inactive ultrasound at 25 days. However, at 40 days, active ultrasound-treated fractures had 16.9% greater bone mineral content at the fracture site than inactive ultrasound-treated fractures. This change resulted in a 25.8% increase in bone size, as opposed to an increase in bone density, and contributed to active ultrasound-treated fractures having 81.3% greater mechanical strength than inactive ultrasound-treated fractures. Discussion and Conclusion. These data indicate that ultrasound produced by a conventional therapeutic ultrasound unit as traditionally used by physical therapists may be used to facilitate fracture repair. However, careful interpretation of this controlled laboratory study is warranted until its findings are confirmed by clinical trials. [Warden SJ, Fuchs RK, Kessler CK, et al. Ultrasound produced by a conventional therapeutic ultrasound unit accelerates fracture repair.

Ultrasound mediated delivery of drugs and genes to solid tumors

“…On the other hand, applications of therapeutic ultrasound are based on depositing ultrasound energy to specifically create effects. These can be mild and nondestructive, such as those generated for healing in physical therapy [22], or more extreme and destructive, such as thermal ablation of tumors [23]. There are presently a large range of therapeutic applications of ultrasound exposures based on the many ways that ultrasound energy can interact with cells and tissues [24].…”

“…The range of applications for these exposures, which are thought to improve blood flow to the treated region, and hence increase the delivery of nutrients and oxygen as well as the removal of cellular wastes, include the relief of inflammation, muscle spasms and pain, in addition to accelerating healing and increasing range of motion [31]. Other applications include facilitating the repair of fractures [22], and preclinical studies have demonstrated how these exposures can accelerate the recovery of sciatic nerve injury [32]. Higher rates of energy deposition are presently being used to ablate solid tumors, such as prostate cancer [33] and uterine fibroids [34].…”

Análise da influência do ultrassom de baixa intensidade na região de reparo ósseo em ratos sob ausência de carga

“…Os resultados obtidos neste estudo para o grupo não suspenso (G1) concordam com Carvalho e Cliquet Jr 20 , que, analisando a ação do US pulsado de baixa intensidade durante 20 dias consecutivos por 20 minutos diários na região proximal dos fêmures de ratas osteopênicas, evidenciaram melhora da arquitetura dos ossos (análise qualitativa), mas não do conteúdo mineral (análise quantitativa), supondo que a análise quantitativa não tenha apontado diferenças devido ao fato de existir grande quantidade de tecido neoformado, o qual ainda não está totalmente mineralizado. Os autores comentam que a duração do tratamento com US de baixa intensidade talvez não tenha sido suficiente para possibilitar a total mineralização das regiões estimuladas, o que não gerou alterações de forma quantitativa, fato que pode ter influenciado os resultados do presente trabalho, uma vez que usamos somente análise quantitativa, além de termos utilizado menor tempo de tratamento quando comparados com outros estudos [21][22][23] .…”

Comparison of Angiogenesis in Bone Defect Healing Process due to the Difference in the Frequency of Low-Intensity Pulsed Ultrasound (LIPUS)

“…In basic research, it was reported osteoblast cell line were maturated and accelerated calcification by LIPUS stimulation [11][12][13] . Furthermore, it was clarified LIPUS exposure promotes healing process and increases bone mineral density by rat femurs fracture model 14,15) . It was also reported about the effect of LIPUS exposure for bone with titanium implant.…”