An Algorithm to Predict Success of Indirect Decompression Using the Extreme Lateral Lumbar Interbody Fusion Procedure

Purpose: The purpose of this study is to define an algorithm that will predict the success of indirect decompression without the need for direct decompression in patients undergoing lateral lumbar interbody fusions. Methods and Materials: A prospective cohort study was undertaken for patients undergoing indirect decompression with lateral lumbar interbody fusion. Patients had to meet the following criteria prior to indirect fusion: lack of facet fusion on CT, absence of free disc fragment or compressive facet joint cyst on MRI, absence of frank osteoporosis, lack of congenital and/or severe spinal stenosis on MRI, and significant reduction (greater than 50%) in leg and back pain at rest. We then assessed which patients at follow-up required a second stage open decompression procedure because of continued back and/or leg pain. Results: Our series included 28 patients who underwent indirect decompression with extreme lateral lumbar interbody fusion. Of the 28 patients, one patient required a second stage open decompression at follow-up. The most common level operated on was the L4-L5 level. Twelve patients underwent more than a single level fusion. Average preoperative lumbar lordosis was 29 degrees and average postoperative lordosis was 45 degrees. The average patient age was 66.3 years and average follow-up was 1.21 years. Conclusions: Our algorithm can be used as an aid to assess which patients may benefit from indirect decompression alone, compared to indirect decompression combined with posterior decompression procedures.