Acupuncture Treatment for Low Back Pain and Lower Limb Symptoms-The Relation between Acupuncture or Electroacupuncture Stimulation and Sciatic Nerve Blood Flow

Abstract

To investigate the clinical efficacy of acupuncture treatment for lumbar spinal canal stenosis and herniated lumbar disc and to clarify the mechanisms in an animal experiment that evaluated acupuncture on sciatic nerve blood flow. In the clinical trial, patients with lumbar spinal canal stenosis or herniated lumbar disc were divided into three treatment groups; (i) Ex-B2 (at the disordered level), (ii) electrical acupuncture (EA) on the pudendal nerve and (iii) EA at the nerve root. Primary outcome measurements were pain and dysesthesia [evaluated with a visual analogue scale (VAS)] and continuous walking distance. In the animal study, sciatic nerve blood flow was measured with laser-Doppler flowmetry at, before and during three kinds of stimulation (manual acupuncture on lumber muscle, electrical stimulation on the pudendal nerve and electrical stimulation on the sciatic nerve) in anesthetized rats. For the clinical trial, approximately half of the patients who received Ex-B2 revealed amelioration of the symptoms. EA on the pudendal nerve was effective for the symptoms which had not improved by Ex-B2. Considerable immediate and sustained relief was observed in patients who received EA at the nerve root. For the animal study, increase in sciatic nerve blood flow was observed in 56.9% of the trial with lumber muscle acupuncture, 100% with pudendal nerve stimulation and 100% with sciatic nerve stimulation. Sciatic nerve stimulation sustained the increase longer than pudendal nerve stimulation. One mechanism of action of acupuncture and electrical acupuncture stimulation could be that, in addition to its influence on the pain inhibitory system, it participates in causing a transient change in sciatic nerve blood blow, including circulation to the cauda equine and nerve root.

Keywords: disc herniation; pudendal nerve; sciatic nerve; spinal canal stenosis; spinal nerve root.

Figure 1.

Schematic diagram of electroacupuncture stimulation of the pudendal nerve. The site for electroacupuncture stimulation of the pudendal nerve is located at a point 50–60% of the distance along a straight line from the posterior superior iliac spine to the lower inner edge of the ischial tuberosity.

Figure 2.

Schematic diagram and X-ray findings of nerve root acupuncture stimulation sits. (Based on the figure Inoue M et al., Electroacupuncture direct to spinal nerves as an alternative to selective spinal nerve block in patients with radicular sciatica – a cohort study. Acupunct Med 2005; 23: 28). Confirmed the referred pain in the part controlled by the nerve root by inserting two acupuncture needles to the part of the nerve root with disorder under X-ray fluoroscopy. The photograph shows that two acupuncture needles were inserted in the part of the nerve root and connected to the electrode for having electric stimulation.

Figure 3.

Changes in low back pain, lower limb pain and lower limb dysesthesia due to electroacupuncture stimulation of the pudendal nerve (left). Changes in continuous walking distance due to electroacupuncture stimulation of the pudendal nerve (right).

Figure 4.

Changes in low back pain, lower limb pain and lower limb dysesthesia due to electroacupuncture stimulation of the nerve root (left). Changes in continuous walking distance due to electroacupuncture stimulation of the nerve root (right).

Figure 5.

This figure shows the sciatic nerve blood flow responses to 58 acupuncture stimulations to the muscle at L6 level (Ex-B2). (Based on the figure from Inoue M et al., Effects of lumbar acupuncture stimulation on blood flow to the sciatic nerve trunk. Acupunct Med 2005; 23: 167).

Figure 6.

Sciatic nerve blood flow (NBF), heart rate (HR) and blood pressure (BP) changes in a typical case of increased sciatic blood flow (upper chart). Sciatic nerve blood flow (NBF), heart rate (HR) and blood pressure (BP) changes in a typical case of decreased sciatic blood flow (lower chart). (Based on the figure from Inoue M et al. Effects of lumbar acupuncture stimulation on blood flow to the sciatic nerve trunk. Acupunct Med 2005; 23: 168).

Figure 7.

In the 33 cases in which sciatic nerve blood flow increased with acupuncture, this figure shows the proportion of increase, decrease and no change in blood pressure and heart rate (upper charts). In the 12 cases in which sciatic nerve blood flow decreased with acupuncture, this figure shows the proportion of increase, decrease and no change in blood pressure and heart rate (lower charts). (Based on the figure from Inoue M et al., Effects of lumbar acupuncture stimulation on blood flow to the sciatic nerve trunk. Acupunct Med 2005; 23:168, 169).

Figure 8.

Changes in sciatic nerve blood flow (NBF), blood pressure (BP) and heart rate (HR) due to efferent electrical stimulation of the pudendal nerve and changes in response after administration of atropine (upper left: Before administration of atropine, lower left: After administration of atropine). Changes in sciatic nerve blood flow (NBF), blood pressure (BP) and heart rate (HR) due to efferent electrical stimulation of the sciatic nerve and changes in response after administration of atropine (upper right: Before administration of atropine, lower right: After administration of atropine).