New, simple, ultrasound-guided infiltration of the pudendal nerve - Topographic basics

PURPOSE. We report the topographic relationship of the pudendal nerve to th e accompanying pudendal vessels and the ischial spine and provide the basic s for an ultrasonographic depiction of these structures. METHODS Twenty-nin e female and 29 male adult human cadavers were, positioned prone to expose the deep gluteal region. In 58 left and 58 right pelves the course of the p udendal nerve and vessels at the ischial spine were evaluated and analyzed statistically (n = 116). RESULTS: Multitrunked pudendal nerves were found i n 40.5 percent with a left-vs.-right ratio of 1:1.5. The diameters of the s ingle-trunked nerves ranged from 1.3 to 6.8 (mean 3.6 +/- 1.1) mm. In 75.9 percent the pudendal nerve was found medial to the accompanying internal pu dendal artery. The distance to the artery ranged from 17.2 min medial to 8 mm lateral (mean, 3.4 mm medial +/- 4.1 mm). The distance to the tip of the ischial spine ranged from 13.4 mm. medial to 7.4 nim. lateral (mean, 2.1 m m medial +/- 3.7 mm). CONCLUSIONS: The knowledge of the close spatial relat ionship between the pudendal nerve and the internal pudendal artery is impo rtant for any infiltration technique and even surgical release. It demands real-time, visually controlled infiltration techniques, such as xvith ultra sound.