Artikel
Animal study of a bioresorbable lumbar interbody fusion cage
Suche in Medline nach
Autoren
Veröffentlicht: | 4. Mai 2005 |
---|
Gliederung
Text
Objective
The objective was to evaluate tissue responses after implantation of a lactic acid polymer cage.
Methods
Eighteen lambs underwent anterior lumbar discectomy, followed by cage implantation filled and surrounded with cancellous bone graft. Five groups of three animals were killed, after 3, 6, 9,12 and 24 months, respectively. The entire lumbar spine with surrounding ligaments and muscles was removed for radiographic, MRI, and CT evaluation. Spinal histologic sections stained with Paragon were used to evaluate - bone density and cellularity, - tissue differentiation at the cage-tissue interface, - bone remodeling and healing, - cage resorption and attendant reactions. Bone apposition activity was evaluated by epifluorescence. Surrounding organs and regional lymph nodes were analyzed to evaluate tissue responses.
Results
- After 3 months, active bone formation was noted around the cage, which was nearly intact. - After 6 months, incipient cage resorption and incorporation into bone with increased peripheral bone remodeling were seen, as well as evidence of fusion inside and outside the cage. - After 9 months, fusion with marked bone apposition was evident. The cage showed further resorption, fragmentation, and fibrous infiltration. - Findings after 12 months were established fusion with mineralization of the osteoid in direct contact with the implant, resorption of about 30% of the initial cage surface, and absence of signs of local or systemic intolerance. - After 24 months, fusion was definitively confirmed with more than 60% resorption of the cage surface. No additionnal tissue reaction was observed.
Conclusions
After two years, fusion was achieved inside and outside the cage; there was no local inflammation, necrosis or osteolysis. The bone directly in contact with the cage exhibited structural features similar to those of neighboring tissue.