Comparative Study of Spinal Fusion for Spondylolisthesis.
The surgical treatment of spondylolisthesis is the topic of this article. Spondylolisthesis occurs when one vertebral body slips forward over the vertebra below. It's caused by a crack in the supporting column of the vertebral body. This fracture can get disrupted, allowing the bone to move forward.

Surgery (fusion) is needed for this condition in order to stabilize the spine. The operation can be done from the front of the spine (anterior). It can also be done from the back (posterior). Without spinal fusion, when the vertebra moves forward, a traction pull is placed on the soft tissues and spinal nerves. The result can be a painful back condition with numbness, tingling, and weakness of the legs.

In this study, surgeons compared these two types of spinal fusion operations used for spondylolisthesis. There were 48 adults treated with either a posterior lumbar interbody fusion (PLIF) or an anterior lumbar interbody fusion (ALIF).

PLIF was used for patients with severe neurologic symptoms. The ALIF was the choice for patients with back pain but minimal signs of nerve involvement. The goal was to find out if adjacent-segment degeneration (ASD) was better or worse with either of these two operations.

ASD affects the vertebra below the level that was fused. It is defined as a loss of more than 10 per cent of the disc height. Other criteria used to define ASD included: a forward slip of the vertebra, symptoms of disc herniation or spinal stenosis, and compression fracture of the vertebrae.

ASD occurred much more often in the PLIF group (82.6 per cent) compared to the ALIF group (44 per cent). Both operations are good treatments for spondylolisthesis. PLIF may be a better choice when the ASD factor is considered.

However, the short-term results were similar between the two groups. Even when ASD occurred, the patients with PLIF didn't need any further surgery. ALIF may be a good way to prevent ASD. If PLIF is used and ASD develops, it’s not linked with a poor outcome.
Jun-Hong Min, MD, PhD, et al. Comparison of Anterior- and Posterior-Approach Instrumented Lumbar Interbody Fusion for Spondylolisthesis. In Journal of Neurosurgery: Spine. July 2007. Vol. 7. No. 1. Pp. 21-26.