Comparing Results of Two Fusion Methods for Spondylolisthesis
In this study, two different methods of spinal fusion are compared for adults with spondylolisthesis. Spondylolisthesis describes a condition in which one of the lumbar vertebrae slips forward over the vertebra below it.

One group of patients were treated using posterolateral fusion (PLF). For the PLF, bone graft from the patient's pelvic bone is used to fuse the spine. In some cases, screws are used to help hold the spine until fusion occurs. PLF is considered the gold standard or best way to treat spondylolisthesis.

The second group was treated with a posterior lumbar interbody fusion (PLIF). With the PLIF method, the surgeon removed the disc. This is called decompression and is the main difference between the two methods. The empty space was filled with a wedge-shaped implant called a ramp. Bone graft was placed on either side of the ramp.

PLIF has some advantages over PLF that suggest it may be a better way to fuse patients with spondylolisthesis. Studies to support PLIF over PLF are lacking. Evidence from studies done so far is weak.

The results of this study did not support the use of PLIF as a better fusion method. After two years, patient results were the same between the two groups. Pain levels, disability, and patient satisfaction were used as outcome measures.

The authors note that there were many more complications in patients with PLIF. Reasons for this include longer operating time and greater loss of blood. PLIF is a more demanding, invasive procedure without improved results over PLF.
References
Per Ekman, MD, et al. Posterior Lumbar Interbody Fusion Versus Posterolateral Fusion in Adult Isthmic Spondylolisthesis. In Spine. September 15, 2007.Volume 32. Number 20. pp. 2178-2183.