Treatment of high-grade spondylolisthesis by posterior lumbosacral transfixation with transdiscal screws: surgical technique and preliminary results in four cases.

In high-grade spondylolisthesis, the surgical treatment should be aimed at achieving good stability to allow solid fusion in the face of high biomechanical forces at the lumbosacral junction. A 360 degrees fusion seems to be able to provide this stability. This is however extensive surgery and many problems and complications have been reported. In order to overcome these difficulties, various new procedures have been published. Most of these techniques aim for a good anterior column support, allowing primary stability and a large bony surface area for fusion. Transfixation of the lumbosacral disc space using a fibular strut graft was published decades ago. Several modifications have been reported since, including the use of threaded cages filled with bone graft. In contrast to the number of these surgical techniques, only few biomechanical test results and small-size clinical studies have been reported in the literature. An interesting technique of lumbosacral transfixation includes the use of transdiscal pedicle screws, described by Abdu et al in 1994. This allows for the use of standard instruments and implants, while biomechanical testing recently has shown improved stability equal to classic PLIF constructs by providing three-column support. Moreover, in high-grade slips this technique is easier to perform than other methods. We have treated four consecutive patients according to this technique with good clinical and radiographic results. The surgical technique is described in detail and a review of the literature is provided.