Summary
Interbody fusion devices are used in human medicine for treating degenerative diseases
of the spine. Currently, there is not a universally accepted assessment tool for determining
fusion, and the definitive criteria for diagnosing a successful interbody fusion remain
controversial. The aim of this study was to describe microscopic and helical computed
tomography (CT) imaging in the assessment of lumbar interbody fusion using cylindrical
threaded titanium expanding cage in sheep. One cylindrical threaded expanding titanium
cage (Proconcept – SA, Orange, France) was inserted through a transperitoneal approach
after radical discectomy and packed with cancellous bone autograft in five adult sheep.
The subjects were euthanatized after three, six, 12, 18 and 24 months. CT images revealed
lumbar fusion at 12 months post operation, whereas microscopic evaluations indicated
the presence of lumbar fusion at 18 months. CT and histological grades were the same
in 65% of the cases observed. There were not a significant difference between CT,
histological and micro radiographic grades. Helical CT scanning can be considered
to be a suitable method for the monitoring of lumbar fusion as it enables observation
of the deposition of bony bridging within the cage.
Keywords
Threaded expanding cage - lumbar spine - vertebral fusion - arthrodesis - animal model
