RESUMEN
INTRODUCTION: Vasectomy is a safe and effective technique to achieve azoospermia, although the failure rate of the technique is less than 1%. Sterility is not immediate so the post-vasectomy seminogram continues o be essential to ensure the success of the technique. The aim of this trial is to establish the attitude when dealing with immobile residual sperm patients. MATERIAL AND METHODS: Cross-sectional analysis of 2,168 vasectomies performed between January 2010 and March 2017. The first post-vasectomy seminogram was performed at 3 months. Those patients with azoospermia did not undergo further controls. Patients with immobile sperm (<100,000/ml o>100,000/ml) were considered potentially fertile and were followed with monthly seminograms until azoospermia was obtained. RESULTS: Of a total of 1,807 patients were included; 1,297 of these had azoospermia at 3 months seminogram and 501 patients had immobile residual sperm. Only 24 patients of this last group showed more than 100.000 sperm/ml; 9 cases showed mobile sperm. All patients who presented immobile residual sperm underwent serial seminograms. Azoospermia was achieved in an average time of 4,5 months in a rage of 4-10 months, regardless of the initial sperm count. An average of 2,5 tests were performed on each patient. All of the patients with mobile sperm required a reintervention. CONCLUSION: All patients with immobile sperm on the first post-vasectomy seminogram will achieve azoospermia regardless of the initial count. Therefore, serial controls until a negative seminogram is obtained are unnecessary.