Comparisive Study Of Two Kinds Of Forepart-expansible Cage Treating Lumbar Instability With Microendoscopic Discectomy

1BackgroundThe 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.2ObjectiveTo compare the clinical effect of the two kinds of forepart-expansible cage in treatment of lumbar instability with microendoscopic discectomy (MED).3MethodsTotally97cases 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.4Results and conclusionEvaluating clinical effect according to the Oswestry disability Index, the result for the circular group was excellent in34cases, good in13cases, fair in3cases and poor in1case. And for the square group, it was excellent in33cases, good in10cases, fair in2cases and poor in1case. 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 at6and12months after procedure (P<0.05). At the end of the follow-up,47cases of the circular group and44cases of the square group achieved bony healing. Complications such as one circular cage overturned and moved backward in3cases, and minor dural trauma occured in1case. 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 "...