External spermatic sheath injection for vasal nerve block

Abstract

The Family Planning Scientific Research Institute in Chongqing China developed a painless and atraumatic technique for external spermatic sheath injection for vasal nerve block (the no-scalpel method) for vasectomy. As of early 1992 this technique has been used to perform 10 million vasectomies in China. Physicians at Cornell Medical Center and the Population Council in New York City have used it for >500 vasectomies. Physicians from both China and the US have not observed any complications from this method. The procedure involves 1st locating the middle-upper 3rds of the median raphe of the scrotum. Using the 3-finger technique the physician then needs to locate and secure the vas deferens under the skin and separate it from the internal spermatic vessels. After placing a 1.5 inch 25-27 gauge needle into a 1-1.5 cm skin wheal in the dermis over the vas deferens midway between the thumb and index finger the needle is advanced all the way in the direction of the external inguinal ring adjacent and parallel to the vas deferens. The syringe is lightly aspirated to verify that the needle is not in a blood vessel. 2-5 ml of 1-2% plain lidocaine is injected gently within the external spermatic fascial sheath. The same procedure is followed for the other vas deferens. After removal of the needle the skin wheal is pinched for several seconds to reduce swelling in the area over the vasectomy site. Lidocaine acts quickly (5 seconds) and works for up to 1 hour. It is safer than bupivacaine and procaine. Thus lidocaine should be the anesthesia of choice.