Low dose of continuous – wave microwave irradiation did not cause temperature increase in muscles tissue adjacent to titanium alloy implants – an animal study

Abstract

BackgroundResearch studies on the influence of radiofrequency electromagnetic radiation on implants in vitro have failed to investigate temperature changes in the tissues adjacent to the implants under microwave therapy. We therefore, used a rabbit model in an effort to determine the impact of microwave therapy on temperature changes in tissues adjacent to the titanium alloy implants and the safety profile thereof.MethodsTitanium alloy internal fixation plates were implanted in New Zealand rabbits in the middle of femur. Microwave therapy was performed by a 2450 MHz microwave generator 3 days after the surgery. Temperature changes of muscles adjacent to the implants were recorded under exposure to dose-gradient microwave radiation from 20w to 60w.ResultsSignificant difference between control and microwave treatment group at peak temperatures (Tpeak) and temperature gap (Tgap= Tpeak-Tvally) were observed in deep muscles (Tpeak, 41.63 ± 0.21°C vs. 44.40 ± 0.17°C, P < 0.01; Tgap, 5.33 ± 0.21°C vs. 8.10 ± 0.36°C, P < 0.01) and superficial muscles (Tpeak, 41.53 ± 0.15°C vs. 42.03 ± 0.23°C, P = 0.04; Tgap, 5.23 ± 0.21°C vs. 5.80 ± 0.17°C, P = 0.013) under 60 w, and deep muscles (Tpeak, 40.93 ± 0.25°C vs. 41.87 ± 0.23°C, P = 0.01; Tgap, 4.73 ± 0.20°C vs. 5.63 ± 0.35°C, P = 0.037) under 50w, but not under 20, 30 and 40w.ConclusionOur results suggest that low-dose (20w-40w) continuous-wave microwave irradiation delivered by a 2450 MHz microwave generator might be a promising treatment for patients with titanium alloy internal fixation, as it did not raise temperature in muscle tissues adjacent to the titanium alloy implant.

Comparative study of the proliferative ability of skeletal muscle satellite cells under microwave irradiation in fractures with titanium alloy internal fixation in rabbits

“…The unique properties of titanium alloy provide an opportunity to investigate the effects of microwaves. Ye et al ( 27 , 28 ) demonstrated that 25 W microwave (2,450 MHz) promoted fracture rehabilitation in an animal model with a titanium alloy implant with no dramatic increase in heat (<41°C). To the best of our knowledge, the effect of microwaves on the skeletal muscles adjacent to fracture sites has not yet been investigated, hindering the application of this technique.…”

“…Given that the magnetic permeability and electric conductivity of titanium alloy is lower than conventional biomedical metal implants ( 25 , 26 ). Ye et al ( 27 ) performed two randomized controlled studies and demonstrated that 25 W microwave (2,450 MHz) improved the healing of fractures with titanium alloy internal fixation without irreversible heat damage (<41°C) in a rabbit model. Ye et al ( 28 ) also reported that the temperature of muscle tissue adjacent to titanium alloy implants is beyond the scope of security (>41°C) when the power of microwave irradiation is tuned to 50 W. This report alone is insufficient and further research is required to reach a new consensus.…”

Study on TiO2 Nanofilm That Reduces the Heat Production of Titanium Alloy Implant in Microwave Irradiation and Does Not Affect Fracture Healing

“…The following experiments verify this hypothesis. In vivo animal studies by Ye et al [ 23 , 24 ] showed that there was no obvious histological change in the skeletal muscles and nerves near the titanium alloy implant when single irradiation with 2450 MHz microwave at a lower dose (20 W~40 W) or continuous irradiation with 25 W titanium alloy fixed rabbit femoral fracture. However, with the increase of power (60 W and 80 W), acute thermal injury of skeletal muscle and nerve could be observed.…”