Introduction: Acupuncture stimulation at the pudendal nerve has been applied to alleviate symptoms of neurogenic bladder dysfunction and chronic pelvic pain syndrome. We have found through our clinical experience that some patients with neurogenic bladder dysfunction who have applied electroacupuncture at the pudendal nerve reported improvement of their low back or lower limb symptoms. To clarify the clinical effect of electroacupuncture at the pudendal nerve, we studied the efficacy of electroacupuncture at the pudendal nerve in patients (lumbar spinal canal stenosis) for whom general conservative treatment (NSAIDs, hot packs, massage, etc.) was ineffective.
Methods: The subjects were 11 patients (mean age 71.3 ± 7.6) with lumbar and lower limb symptoms that were not relieved by conventional conservative treatment for 2 months. The point for acupuncture stimulation to the pudendal nerve is located in the gluteal region (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). Two acupuncture needles were inserted in this region. These two needles were used as electrodes for low-frequency electroacupuncture treatment. A total of eight times (once a week), stimulation was performed at the pudendal nerve, on the same side of the lumbar and lower limb symptoms. Assessment of low back pain, lower limb pain, and lower limb dysesthesia was performed using a visual analog scale (VAS). Continuous walking distance was verified with reports by the patients themselves.
Results: The VAS values for low back pain changed from 52.5 ± 15.1 mm (M ± SD) to 47.1 ± 13.8 mm, for lower limb pain from 63.3 ± 7.2 mm to 40.6 ± 12.3 mm, for lower limb dysesthesia from 64.1 ± 10.9 mm to 46.3 ± 17.1 mm, and for continuous walking distance from 103.5 ± 40.7 m to 250.5 ± 123.3 m. As a result of electroacupuncture stimulation of the pudendal nerve, improvement was seen in low back pain in 2of 11 cases, in lower limb pain in 8 of 11 cases, and in lower limb dysesthesia in 6 of 11 cases, while continuous walking distance improved in 4 of 7 cases.
Discussion: These results indicate that electroacupuncture of the pudendal nerve is an effective treatment for lumbar and lower limb symptoms due to spinal canal stenosis. Since this method was effective with cases that did not respond to conventional conservative treatment (NSAIDs, hot packs, massage, etc.), we presume that it is more effective than conventional conservative treatment. As electroacupuncture at the pudendal nerve can be performed using acupuncture needles, it enables a nonsurgical, percutaneous approach, which is very simple and a safe method of treatment. However, there may be a possibility that the patient will experience unpleasant sensation in the pudendal area during stimulation. For this reason, we propose that this method be applied secondary to acupuncture stimulation of the lumbar and lower limb muscles (general acupuncture treatment). A possible mechanism underlying the effect of electroacupuncture is that electrical stimulation at the pudendal nerve improves circulation to the cauda equine and/or sciatic nerve.