Background. Foraminal stenosis is often encountered in patients undergoing decompression for spinal stenosis. Given the increased resection of facets and the presence of the more sensitive dorsal root ganglion, it is hypothesized that patients with foraminal stenosis have poorer postoperative outcomes. Methods. Thirty-one patients undergoing decompression without fusion for lumbar spinal stenosis were evaluated. The degree of foraminal stenosis was determined by 2 independent reviewers for absence of fat around the nerve roots. ImageJ digital imaging software was also used to evaluate the foraminal area. Patients with foraminal stenosis were compared with those without using the Oswestry Disability Index (ODI) and a numerical pain scale for back and leg pain at a minimum of 1 year follow-up. Results. Twenty patients in the foraminal stenosis group were compared with 11 without foraminal stenosis. There were no significant differences between the 2 groups regarding age, sex, comorbidities, number of levels operated on, preoperative ODI, back pain or leg pain scores. The foraminal area was significantly smaller in the foraminal stenosis group. Patients without foraminal stenosis reported significant improvements in ODI (mean 26.0), back pain (mean 3.1) and leg pain scores (mean 5.5). Patients with foraminal stenosis reported significant improvements in ODI (mean 18.8) and leg pain (mean 2.5) but not in back pain (mean 0.3). Comparing the 2 groups, the patients with foraminal stenosis had significantly less improvement in back pain (p = 0.02) and leg pain (p = 0.02). Conclusion. The results of this study suggest that presence of foraminal stenosis is a negative predictor for successful outcome following decompression surgery. This may be related to the increased instability that occurs when a foraminotomy is required. Spinal fusion may reduce this effect, and further study is required. NO DISCLOSURES