Biodegradable miniplates (LactoSorb): long-term results in infant minipigs and clinical results.

Metallic plates are known for their passive intraosseous transmission in the growing skull. To avoid plate removal, resorbable material with strength comparable to that of metallic plates and predictable resorption would be desirable. This should be accomplished without causing inflammatory complications and foreign body reactions often seen with highly crystalline poly-L-lactic acid or pure polyglycolic acid implants. In an animal experiment in four young Göttingen minipigs, the resorbable poly-L-lactic acid/polyglycolic acid copolymer LactoSorb was tested previously. In addition to testing the mechanical properties, the process of degradation and sub- versus epi- or supraperiosteal application of the miniplate device LactoSorb was evaluated using a frontal cranioosteoplasty model. Furthermore, LactoSorb was used in 10 patients with craniosynostosis or craniofacial trauma. During degradation, the absorbable poly-L-lactic acid/polyglycolic acid miniplates acted like metal plates because they also displayed passive intraosseous transmission in the growing animal model. Degradation took 12 to 18 months and was not delayed by bony incorporation. Their mechanical properties proved to be sufficient in craniofacial surgery. Epiperiosteal plating prolonged the passive intraosseous transmission effect during the first 3 months after surgery. There were no major inflammatory reactions seen in the experimental and/or in the clinical study.