Results of Double-Level Posterior Spine Fusion
Posterior lumbar interbody fusion (PLIF) is often used to fuse the spine. Patients with degenerative lumbar diseases with pain and instability are often treated with PLIF. Most studies report the results of single-level PLIF. This study from Japan reports the results of double-level PLIF.

Nineteen (19) patients were followed for at least two years. Everyone had two levels of the lumbar spine fused. Measures of success included improved pain, increased activity, and improved lumbar lordosis.

Lordosis is the angle of the bones forming the curve of the lower spine. Decreased lordosis means the back is flat. A curved low back occurs with increased lumbar lordosis. A flat back increases the pulling load on the spine causing pain. That's why getting the right amount of lordosis is important.

In this study double PLIF had good results that were maintained for two or more years. The researchers report the unfused segments even tried to adjust to the fusion in an effort to keep the normal lumbar lordosis.

The authors also say the double-level PLIF didn't have as good of results as a single-level PLIF. The difference may be because patients with degenerative disease at more than one level also have other problems. There was more neurologic damage. Almost half of the patients in this study also had arthritis affecting their knees.

Overall the results of the double-level PLIF were reported as "satisfactory." The operation is considered invasive based on the amount of blood loss and how long the operation takes.
Akira Hioki, MD, et al. Two-Level Posterior Lumbar Interbody Fusion for Degenerative Disc Disease: Improved Clinical Outcome with Restoration of Lumbar Lordosis. In The Spine Journal. November/December 2005. Vol. 5. No. 6. Pp. 600-607.