The observation of low or middle power microwave radiation on tissues adjacent to titanium alloy implants / 中华物理医学与康复杂志

ABSTRACT

Objective To observe the influence of low or middle power microwave radiation on tissues adja-cent to titanium alloy implants. Methods Titanium alloy internal fixation plates were implanted into the upper femur of the right side of New Zealand white rabbits, the left femurs served as the control. Then the femurs were exposed to 20, 40, 60, or 80 W of microwave radiation at a frequency of 2450 MHz for 30 minutes, and real-time temperature of the implants and its adjacent muscles were recorded. The nerve conduction study of the sciatic nerve was performed by stimulating the nerve and recording from gastrocnemius in both groups. Finally, all the rabbits were sacrificed and histo-logical studies were performed on nerve and muscle sections. Results Compared to the control limbs, temperatures of limbs with titanium alloy implants increased significantly when exposed to microwave radiation at 60 and 80 W ( P0.05). Pathological examination showed obvious congestion and bleeding in the intercellular spaces of skeletal muscle cells in the experiment group when exposed to radiation at 60 W, with no ob-vious pathological changes found in the sciatic nerve. However, when exposed to radiation at 80 W, vacuoles appeared in myocytes, the cellular structure was destroyed and the myelin sheath of the sciatic nerve swelled. Conclusion Ex-posure to microwave irradiation at 20 and 40 W, but not 60 and 80 W exerts no adverse effects on nerves and muscles adjacent to titanium alloy internal fixation plates. Consequently, continuous wave microwave irradiation at low powers (20~40 W) is a safer auxiliary treatment for limbs with titanium alloy implants.