Abstract:

BACKGROUND: The forepart-expansible cage is a kind of novel expansible cage developed in recent years, of which there are circular and square cages all with larger contact area.
OBJECTIVE: To compare the clinical effect of the two kinds of forepart-expansible cage in treatment of lumbar instability with microendoscopic discectomy (MED).
METHODS: Totally 97 cases with lumbar instability were underwent posterior lumbar interbody fusion (PLIF) using double tractors swing microendoscopic discectomy. Fifty-one patients were treated with the circular cages and forty-six with the square cases bilaterally or unilaterally.
RESULTS AND CONCLUSION: Evaluating clinical effect according to the Oswestry disability Index, the result for the circular group was excellent in 34 cases, good in 13 cases, fair in 3 cases and poor in 1 case. And for the square group, it was excellent in 33 cases, good in 10 cases, fair in 2 cases and poor in 1 case. There was no significant difference between the two kinds of forepart-expansible cages. The vertebral height loss rate of the circular group was higher than that of the square group at 6 and 12 months after procedure (P < 0.05). At the end of the follow-up, 47 cases of the circular group and 44 cases of the square group achieved bony healing. Complications such as one circular cage overturned and moved backward in 3 cases, and minor dural trauma occured in 1 case. The result indicates that the circular cage is much better with lower subsidence rate, larger contact area and more excellent stability. And two square cages can be placed conveniently unilaterally using the “isolation placing technique”.