Forty cases of foraminal (28) and lateroforaminal (12) herniated discs treated either by nucleolysis (N.L.) or percutaneous automated nucleotomy (P.A.N.) were investigated over a period of 12 months or more. The group of patients treated with P.A.N. (15 males, 5 females) with a mean age of 41.8 years, had severe radicular pain in 25% of cases, caused by foraminal (15 cases) and lateroforaminal (5 cases) herniated discs which were predominantly located at the L4-L5 level (12 cases). The group of patients treated with N.L. (13 M, 7 F) with a mean age of 50.3 years complained of severe radicular pain in 65% of cases, caused by foraminal (13 cases) and lateroforaminal (7 cases) disc herniations evenly distributed over the last three mobile segments. The overall results obtained with N.L and P.A.N. showed a 67.5% success rate. The best results were obtained in cases of cruralgia with severe radicular pain caused by foraminal herniated disc at the L3-L4 or L4-L5 levels. A significantly better result was obtained in the group of patients treated by N.L. (80% success rate) than in the group of patients treated by P.A.N. (p < 0.04).