Radiographic Outcomes Measures

For patients who were assigned decompression with interlaminar stabilization, upright neutral lateral, flexion, and extension radiographs were obtained at each time point. For patients in the decompression with fusion control group, the same radiographic data were obtained, with the exception of flexion and extension radiographs being withheld at the 6-week and 3-month time points. All radiographic images were sent directly from the study sites to an independent core radiography laboratory (Medical Metrics Inc, Houston, Texas) for evaluation.