The Experimental Study And Clinical Trial Of The Intra-vas Device, A Novel Contraceptive Method

Vasectomy for contraceptive purpose is one of the most frequently performed minor operations. It has been reported that over than 40 million men rely on vasectomy for contraception. However, vasectomy is still unacceptable in some countries due to reasons of religion or fear of its side effects. Contraceptive mechanism of vasectomy is based on the complete occlusion of the vas. Some unavoidable complications, including congestive epididymitis, sperm granuloma and sperm antibody reactions, are believed to originate from acute and complete vasal blockage. Many intra-vas devices or chemicals, such as threads, cooper wires, electric devices and styrene maleic anhydride (SMA), have been designed to maintain the patency of the vas deferens, in order to reduce those complications while preserving the contraceptive efficacy. However, up to now, most researches have been limited to animal experiments or small-scale clinical trials for various reasons. Two experimental studies, using epidural catheters filled with nylon threads, demonstrated good contraceptive efficacy and reversal with reduced epididymal impairment. Based upon these observations, a series of intra-vas devices (IVDs) has been designed and manufactured by our research group during the past decade. Previous IVDs were mainly made of polypropylene and polytef respectively. Small scale clinical trials demonstrated that it had good contraceptive efficacy and low complication rates. But polypropylene and polytef were not eligible to be implanted into vas lumen for long period. Simultaneously, the design of the previous devices had many shortcomings, for example, hard to be fixed in the vas lumen. In order to resolve these problems, our research team designed and manufactured a novel device which is mainly composed of urethane. No-scalpel vasectomy (NSV) is a refined technique, which offers significant advantages over conventional vasectomy and has been used worldwide. In order to compare the contraceptive efficacy, safety and reversibility of the urethane...