Comparison of self-reinforced poly-L-lactide and steel wire in fixation ofsternotomy in rabbits

Background and Aims: To investigate the healing of sternotomies fixed with biodegradable self-reinforced poly-L-lactide (SR-PLLA) wire and comparing i t with steel wire fixation. Material and Methods: Sixteen rabbits (15 Chinchilla and one New Zealand Wh ite rabbit) were operated on. Two parallel holes of 1.5 mm in diameter were drilled in the sternum at the level of the second and third rib and simila r holes of 0.8 mm were drilled at the level of the third and fourth rib. A transverse sternotomy was created between both drill hole pairs. The sterno tomy with larger drill holes was fixed with 1.1-mm thick SR-PLLA wire. The sternotomy between the smaller drill holes was fixed using 2.0 steel wire. The animals were sacrificed at 2, 7, 26 and 52 weeks postoperatively and sp ecimens were taken, radiographed and studied by both light and scanning ele ctron microscopy. Results: One rabbit died at four months postoperatively as a result of gast rointestinal problems. No other complications were seen. The SR-PLLA wire w as slowly degraded. There was no disturbance of bone healing. The implants were surrounded by a fibrous tissue capsule, which also contained chronic i nflammatory cells. Both SR-PLLA and steel wires provided sufficient fixatio n security. No differences in the healing of the sternotomies were observed between SR-PLLA and steel wire fixation. Conclusions: SR-PLLA wires are biocompatible and useful for sternotomy fixa tion. They may be suitable for use in clinical applications.