Imaging of biodegradable osteosynthesis materials by ultrasound.

Abstract

Biodegradable osteosynthesis materials are not radio-opaque and therefore not visible on conventional X-rays. The aim of this study is to investigate the use of ultrasound for imaging biodegradable materials to detect and monitor the degradation process. Forty-six patients had two different polylactide osteosynthesis fracture plate materials used for the fixation of midfacial fractures. A 7.5 MHz ultrasound transducer with a 4.2 x 0.9 cm footprint was used by two examiners at approximately 4-month intervals over 36 months to monitor changes of the latero-orbital and infra-orbital rims. Intrinsically amorphous 50 : 50 poly(D,L)lactide reached the maximum of thickness (about 300% of the initial thickness) between 14 and 18 months post-implantation and was totally resorbed in clinical and ultrasound examinations 30 months post-implantation. In 85 : 15 poly(L,D)lactide plates, the maximum of thickness (about 300% of the initial thickness) was reached between 22 and 26 months post-implantation and resorption was still in progress 36 months post-implantation. Ultrasound examinations are suitable for detecting and monitoring the degradation process of biodegradable osteosynthesis plates in the peri-orbital region.