Non-invasive reversal of intraluminal vas deferens polymer injection-induced azoospermia--technology

The rationale and technique underlying a novel concept of non-invasive removal of an intravasal vas deferens polymeric contraceptive drug to reverse drug injection-induced azoospermia are explained. Thus the conventional methods of surgical exploration to remove vas deferens plugs and intravasal injection of solvents to flush out contraceptive drugs are to be replaced by steps which will be readily accepted by subjects.

The approach is based upon the non-invasive application of specific forces to various segments of the vas deferens so that non-sclerosing and non-tissue-adherent compounds, in particular styrene maleic anhydride (SMA) can be expelled. Forces are generated by palpation; percutaneous electrical stimulation; vibration application; and percussion. The forces help to propel the intravasal polymer towards the ejaculatory duct for expulsion during ejaculation. All aspects of the total technique are clinically acceptable, simple, atraumatic, unlikely to cause pain and discomfort even without tranquilizers, local or general anaesthetics. The procedure may be repeated several times in different sittings spaced apart by about one week to achieve adequate plug expulsion.

Model experiments demonstrated the feasibility of the concept. The polymer was nonadherent and could be moved within the vas deferens by the application of specific forces. Sufficient removal was possible to enable spermatic fluid to be transported along a region previously occupied by the polymer. A corroborating subhuman primate study by an independent investigator has shown that the semen profile becomes normal following the reversal.

Adoption of the new technique may provide a means of non surgical restoration of normal semen profile after a period of fertility control obtained by intravasal drug injection.