New Horseshoe Cage for Spinal Fusion
There's a well-known way to surgically treat chronic low back pain caused by disc degeneration--spinal fusion. In recent years, doctors have used titanium cages as part of the fusion process. The disc material is removed, and the cage is inserted between the two vertebral bones. The cage keeps the same disc height and gives the spine balance and support.

The cages can be inserted from the front of the spine. This is called anterior lumbar interbody fusion (ALIF). When inserted from the back, it's called a posterior lumbar interbody fusion (PLIF).

There are problems with both methods. For example the success rate with the ALIF varies too much. The PLIF may not work if the disc itself is the cause of pain. Doctors are trying to find ways to overcome these problems. A new titanium cage has been designed with these issues in mind. It's horseshoe-shaped and held in place with screws. The cage is also filled with bits of bone to form a bone graft for better fusion.

In this study, doctors in England compared the ALIF with the PLIF using the horseshoe-shape cage. Before the operation each patient had X-rays, MRIs, and a discography. During discography, fluid is injected into the disc to see if the disc is the source of pain. The results after surgery were measured by changes in imaging, back pain, and work capacity. All patients were active at work.

The authors report no difference in the overall results between ALIF and PLIF using the horseshoe cage. Measures included function, return to work, compensation rate, and disability benefit. Problems after the operation were about the same in the two groups.

These researchers conclude that the horseshoe cage can be used with good results for lumbar fusion. Either approach (ALIF or PLIF) can be used with equal success. There were no failures and a good fusion rate for both methods.
S. S. Madan and N. R. Boeree. Comparison of Instrumented Anterior Interbody Fusion with Instrumented Circumferential Lumbar Fusion. In European Spine Journal. December 2003. Vol. 12. No. 6. Pp. 567-575.