title: Imaging of biodegradable osteosynthesis materials by ultrasound.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  Ultrasound examinations are suitable for detecting and monitoring the degradation process of biodegradable osteosynthesis plates in the peri-orbital region.
authors.affiliation: Department of Maxillofacial Surgery, Otto-von-Guericke-University, Magdeburg, Germany. wolfgang.heidemann@medizin.uni-madgeburg.de
authors.forename: W
authors.initials: W
authors.lastname: Heidemann
authors.forename: K L
authors.initials: KL
authors.lastname: Gerlach
mesh_terms: D020341:Absorbable Implants; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001672:Biocompatible Materials / Q000737:chemistry*; D001860:Bone Plates; D001863:Bone Screws; D005260:Female; D005500:Follow-Up Studies; D005593:Fracture Fixation, Internal / Q000295:instrumentation; D017102:Fracture Healing; D006801:Humans; D008297:Male; D008875:Middle Aged; D009915:Orbit / Q000000981:diagnostic imaging; D009917:Orbital Fractures / Q000000981:diagnostic imaging / Q000601:surgery; D011091:Polyesters / Q000737:chemistry*; D011474:Prosthesis Design; D013499:Surface Properties; D014463:Ultrasonography
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; C033616:poly(lactide)