Lumbar disc herniations and degenerations are very prevalent lesions, and many surgical approaches have been adopted for these conditions. However, the results of conventional or extensive operations have not always been satisfying. In 1975, the author developed the technique of percutaneous nucleotomy in an effort to avoid the major surgeries then employed. Fenestration of the annulus and partial resection of the nuclear substance are achieved percutaneously by a posterolateral approach. Intradiscal pressure is reduced considerably, and relief of irritation of the nerve root or the pain receptors around the disc is obtained. The extraction of the herniated portion of the disc is not achieved by the procedure. However, the amount of herniated disc substance may be reduced by disc decompression with suction. The procedure can be done in a radiology department under local anesthesia and requires 30 to 60 minutes. Of 136 cases followed, 72% of the patients are satisfied. The concept and theoretical considerations, surgical instruments, details of improved technique, results, and complications of percutaneous nucleotomy are introduced and compared with the original technique.