159 patients with intermittent neurogenic claudication due to single- or two-level degenerative lumbar spinal stenosis were selected for inclusion. The purpose of this randomized controlled trial was to determine how treatment with an interspinous process device without bony decompression compared to bony decompression 2 years post-operatively. At 2 years, there was no significant difference between groups in terms of successful recovery, disability, function, leg pain, and patient perceived recovery. However, both back pain and reoperation rate were significantly greater in the interspinous process device patients.