The tissue origin of low back pain and sciatica: a report of pain response to tissue stimulation during operations on the lumbar spine using local anesthesia. In an effort to define the origin of low back pain and sciatica, 193 patients were carefully studied using progressive local anesthesia. These patients had surgery for herniated discs, spinal stenoses, or both. Various tissues were stimulated during the performance of these lumbar spinal operations. This article discusses our observations and the results of that study. 