New studies with intravasal devices. The soft valve.

In contrast to the results that were obtained with rigid ended prosthetic devices, effective sperm transport occurred for prolonged periods of time through the IITRI Vas-Valve, which had soft silicone rubber flexible end tubes when implanted in the vasa deferentia of dogs. Such transport could be halted by device occlusion with stainless steel springs or with shuttle stem valves. Opening the devices resulted once more in the passage of spermatozoa as well as the production of offspring, indicating that these devices have the potential for being useful as a human male contraceptive method. More research needs to be performed to determine why there is an over-all decrease in sperm output after device implantation and to evaluate and adverse side effects of such devices. The presence of Dacron velour-covered suture rings on the devices permitted effective tissue ingrowth and prevented leakage or recanalization in all cases.