Bioabsorbable polylactide composite membrane for cranial defect

Abstract

The aim of the study was to develop a composite membrane for cranial defects. Cranial defects may occur as a result of innate anomalies, trauma, surgery, infectious conditions, or following improvements of cosmetic appearance or reestablishment of rigid protection for the underlying brain. Several criteria exist for osteosynthetic devices. The membrane should have sufficient mechanical strength, pliability, stiffness, and should not cause bone erosion or interface with bone growth. In this study, the composite membrane was also meant to guide bony tissue to fill the wound site and the same time to exclude the entry of fibroblasts. The membrane was composed of a plate and a knitted tubular mesh attached to the other side of the plate. Two different material combinations were used in this study. First, the plate was made of P(L/DL)LA 70/30 and the tubular mesh of P(L/D)LA 96/4. In the second structure, both the plate and the mesh were made of PLGA 80/20. One side of the composite plate was porous mesh and the other a smooth plate. Gamma-sterilised specimens were tested in vitro. Wet weight, GPC, and mechanical properties were observed during 12 weeks of hydrolysis. The wet weight loss of the P(L/DL)LA 70/30 plates was small, and their molecular weight decreased steadily by 20-30 %. The plates' mechanical properties also diminished uniformly in the in vitro tests. The PLGA 80/20 specimens degraded faster than the P(L/DL)LA 70/30 plates and could be tested only eight weeks in vitro. Their wet weight increased markedly in hydrolysis, and their molecular weight and mechanical properties diminished to zero during the eight weeks. /Kir10