The purpose of this article is to present the clinical results of the prospective series of studies on percutaneous nucleotomy (PN) for lumbar disc herniation and to introduce current criteria of patient selection for PN. Since 1983, 107 patients were treated with PN (Hijikata's method), 85 of whom had a follow-up period of more than 2 years. Of these 85 patients, 54 had successful results. Clinical findings and various imaging evaluations (eg, magnetic resonance imaging and computed tomography after discography) before PN, as well as operative findings, were used to study the surgical outcomes of both the successful and unsuccessful groups. The results yielded the following new criteria for patient selection for PN: 1) age less than 40 years; 2) no perforation of the posterior longitudinal ligament and no degenerative canal stenosis detected by computed tomography after discography; 3) no malformation of the neural structure; 4) more than Grade 4 on manual testing of innervated muscles; and 5) more than 6 months of conservative treatment before PN.