In past years, lumbar nerve lateral entrapment seldom has been diagnosed. A presumptive preoperative diagnosis has been made based on clinical findings and radiographs demonstrating disc resorption. The Computed Tomography scan has made it possible to diagnose the lesion with certainty and accuracy. Treatment for patients who do not respond to conservative measures is a bilateral minimal partial laminectomy. The lateral canal is enlarged by removing the medial and anterior parts of the superior articular process. Adhesion formation is prevented by placing a free fat graft posterior to the dura. Instability is diagnosed by examining stress radiographs and, when present, is treated by a one level posterolateral fusion. After operation, marked improvement was obtained in 62% of patients and slight improvement in another 21%; 17% were unimproved. Sixty-two per cent of patients reported no pain or mild pain. Sixty-six per cent resumed their previous occupation.