Persistent spermatozoa after vasectomy: a survey of British urologists

To determine the rate of, and main indications for, repeat vasectomy in our department, and to assist in policy-making procedures by determining how urologists in England and Wales manage those men who show small but persistent quantities of motile or non-motile spermatozoa in their ejaculate after vasectomy.

A retrospective review of all of the vasectomies and repeat vasectomies performed by the Urology Department at Southmead Hospital during a 14-month period was undertaken to determine the rate of and indications for repeat vasectomy. Subsequently, every consultant urologist in England and Wales was canvassed with a questionnaire to determine whether they repeated vasectomy in the presence of persistent motile or non-motile sperms and if so, after what time interval. Any experience of pregnancies arising from these groups was also assessed, and any relevant comments invited.

The local review revealed that 5% of all vasectomies were repeated within 6-36 months. Of these, 87% were performed because of persistent sperms in post-vasectomy semen samples, the majority of which showed sperm concentrations of one in 50 to one in 100 high-power fields. A response of 56% was obtained to the questionnaire and of those responding, 23% never repeated a vasectomy where there were presistent non-motile sperms, but almost all urologists would eventually repeat vasectomy where motile sperms were present. The median interval between the first and second vasectomies was 6 months and 12 months for motile and non-motile sperm, respectively. Apart from those cases already published, there was little experience of pregnancy arising from men with persistently few motile or non-motile sperms.

The risk of pregnancy occurring in the presence of non-motile sperms was estimated to be less than the established risk of late recanalization, and this survey provides both logical and medico-legal support for issuing a 'special clearance' to men with few persistent non-motile sperm after vasectomy, providing the risks of pregnancy are properly discussed and documented. For motile sperm, however, there appears to be a stronger precedent for repeating the vasectomy. The technique used for post-vasectomy semen analysis was also an important consideration when determining any policy regarding such cases.