Timo Waris

The Role of Polyglycolic Acid Rods in the Regeneration of Cartilage from Perichondrium in Rabbits

The role of polyglycolic acid (PGA) rods in the regeneration of cartilage from perichondrium was investigated in 12 growing rabbits. The fifth rib cartilage was resected subperichondrially from both sides. A 10 X 1.5 mm self-reinforced polyglycolic acid (SR-PGA) rod was inserted on one side to replace the resected cartilage and the retained perichondrium was sutured around the implant. On the control side the perichondrium was shaped into a tube without an implant. Samples were taken 4, 12, and 20 weeks after operation. Pronounced neocartilage formation was seen on both sides, and had grown to form a tube around the implant. Also new bone formation was seen in 12 and 20 weeks. Foreign body reaction was seen inside the implants in every animal.

Poly-L-lactic acid plate for covering of small cranial bone holes: an experimental study in rabbits

Abstract Cranioplasty was performed on 13 adult New Zealand white rabbits to investigate the potential of poly-L-lactic acid (PLLA) plates for cover of small cranial bone holes. Two holes of 5 mm in diameter were drilled through the parietal bone, one on each side of the skull. One was covered with a self-reinforced polylactide (SR-PLLA) plate while the other one was left empty, with only the periosteum covering. The results were analysed by taking X-rays and samples for histological examination 3, 6, 24 and 48 weeks postoperatively. There were no special radiological findings. Histologically, new bone formation was clearly seen on the implant side at 24 and 48 weeks after the operation, while there was only a slight reaction on the control side in the same rabbit. We conclude that SR-PLLA appears to enhance the healing of cranial bone.

Stabilization of anterior thoracoplasty with a resorbable, self-reinforced poly-l-lactic acid rod: an experimental study in rabbits

Thoracoplasty using a self-reinforced, poly-l-lactic acid (SR-PLLA) rod was performed on 14 growing rabbits. The 4th–6th rib cartilages were resected subperichondrially on both sides, preserving the perichondrium, and a transverse sternotomy was performed between the levels of the 3rd and 4th ribs. The caudal part of the sternum was depressed, creating an experimental pectus excavatum, and fixed in this position using a 2 × 30 mm SR-PLLA rod placed trasversally on the sternum and fixed laterally between the 4th and 5th ribs on both sides. A CT examination was performed on each rabbit postoperatively and before killing. Samples were taken 1, 6, and 12 months after the operation. Both CT and clinical findings showed that the experimentally created pectus excavatum had maintained well throughout the experimental period. Regeneration of the resected rib cartilages was observed in every rabbit.