Results of First Tests on New Anterior Lumbar Fusion Device
The Swedish Lumbar Spine Study Group has shown that spinal fusion works better than nonsurgical care for chronic low back pain. The goal now is to find a way to fuse the spine with the least amount of surgical invasion. Toward this end researchers in Germany tested a new stand-alone device against three other fusion methods.
Fusion can be done from the front (anterior) or back (posterior) of the spine. An implant or cage placed between the two bones of the vertebrae is often used. This is called an anterior lumbar interbody fusion or ALIF. Screws may be added through the bones from the back to add stability.
The Swedish Study Group has shown now that the added screws don't help. The extra surgery costs more and often means more problems. The new stand alone ALIF tested in this study is inserted anteriorly. It doesn't need any extra screws posteriorly to hold it in place.
When tested in eight cadavers the results of the new "stand alone" device were just as good as with the standard fusion methods. The new ALIF implant has a cage that fits between the vertebrae from the front. There are two fixation screws. One goes into the bone above and the other goes into the bone below. Both screws are inserted at an angle instead of straight in.
The stand-alone ALIF gives just as much, if not more, stability as the other standard ALIF devices but without the added posterior screws. This study does not show how long the fusion will last or how it will hold up under daily use. The next step is to conduct clinical trials with the new device on a small number of people over a longer period of time.
Christopher M. J. Cain, MD, et al. A New Stand-Alone Anterior Lumbar Interbody Fusion Device: Biomechanical Comparison with Established Fixation Techniques. In Spine. December 1, 2005. Vol. 30. No. 23. Pp. 2631-2636.