5 YEARS OF EXPERIENCE WITH BIODEGRADABLE IMPLANTS IN PEDIATRIC-SURGERY

After successful animal research on minipigs and calves, it was decide d in January 1988 to begin the clinical application of PLLA (poly-L-la ctide) threaded plugs, nuts and woven bands made of PDS (poly-dioxanon ). The implants were made of pure crystalline 1-1-PLLA with an average molecular weight between 220 000 and 500 000 I.E. Mechanical testing revealed a Young's modulus of 4000 N mm(-2), a fracture elongation of 2%, and strength values under tension and compression and bending of 5 5, 110 and 120 N mm(-2), respectively. The PDS bands (Ethicon Corp., t ype XX40) are commercially available items. Operations were carried ou t on 32 children, aged 11 months to 17 years, in 15 cases for craniofa cial malformations, in 16 patients for neurotraumatological lesions an d in 1 girl for refixation of an osteochondral flake of the patella. T he follow-up time ranged from 3 months up to 5.6 years, with an averag e of 3 years. The stability achieved was comparable to that of metal i mplants. No foreign-body reaction or local infections were observed, a nd it did not become necessary to remove any of the resorbable implant s. Furthermore, there was no interference with skull growth. In accord ance with these results, PLLA implants fulfill the needs of skull surg ery, and it is intended to increase the application of this type of ma terial to orthopaedic traumatology in children.