This paper begins with general discussion of chronic pain, in which the complex nature of this symptom is pointed out and the incorrect application of the widespread distinction between 'organic' and 'psychogenic' pain is criticized. A different classification which has proved clinically valuable is then briefly discussed. Subsequently, there is a discussion of the symptom of low back pain, a frequent disorder as demonstrated by the epidemiologic investigation reported. Then, reference is made to chronic low back pain which is often treated by surgical intervention such as operation for prolapsed intervertebral disc (PID). To conclude, a detailed report is presented of a study of 55 patients all of whom had been subjected at least once to a PID operation without success and who subsequently applied for partial percutaneous rhizotomy (PPR). Every patient was interviewed in depth and the results of these interviews are presented, classified by the main topics discussed. In addition, 6 months after PPR, a follow-up interview was conducted concerning the therapeutic results in the 31 patients who underwent this procedure.