New, simple, ultrasound-guided infiltration of the pudendal nerve - Ultrasonographic technique

PURPOSE: Anesthetic infiltration of the pudendal nerve at the ischial spine can relieve perineal pain in cases of compression or distention. The aim o f our study was to look for a real-time, visually controlled infiltration t echnique using ultrasound. METHODS: Fifty-three volunteers were examined in a prone position using a 3.5-MHz curved-array probe in color-coded Doppler mode. The deep gluteal region was scanned in two perpendicular planes, lon gitudinal and transverse to the internal pudendal artery. RESULTS: On the t ransverse planes the ischial spine, the sacrospinous ligament, and the inte rnal pudendal artery were depicted in all but two cases. In 47.2 percent of the cases one trunk of the pudendal nerve was detected directly. Nerves co nsisting of more than one trunk were not found. The thickness of the nerve ranged between 3.5 and 7 mm. CONCLUSIONS: In almost one-half of the cases a direct ultrasound-guided infiltration of the pudendal nerve is possible. I n the remaining cases the nerve can be detected and blocked indirectly, usi ng the ischial spine or the internal pudendal artery as a landmark.