Drug-induced Platelet Antibodies Sir,-we Read with Interest the Letter Of

during the past 13 years in Canada where, possibly because an actual fee for the surgery is involved, the situation is more individualized and contractual, with the consequent possibility of litigation in the event of failure. Therefore for personal and legal reasons I could not guarantee sterility if any spermatozoa-motile or non-motile-were present in the semen. In the early years I required only one negative specimen but later increased this to two. Because of two pregnancies, with motile spermatozoa, I have for the past five years followed a routine of two negative specimens, two weeks apart, two months after the operation followed by a third negative specimen one month later. Thus the patient and I are satisfied that every reasonable precaution has been taken. If a specimen shows any sperm, then specimens are repeated monthly for 8-12 months. At the end of this variable period a second operation is performed as before under local anaesthetic with no difficulty, using a fresh site on the vas if there is any granulomatous tissue formation from the previous surgery. A total of 14 patients, 12 with non-motile sperm and two with large motile sperm counts, had repeat vasectomies performed and in every case was aspermic one month after operation. It was noted that, generally speaking, the older the patient, the longer the period required to attain azoospermia, the oldest (75 years) taking 18 months. While I have a routine based on a period of time, the vital factor is the frequency of coitus, which in the older patient with failing sexual function requires more time and more ejaculations to complete evacuation of the spermatozoa. The time schedule was strictly adhered to in order that if recanalization takes place, which is more probable in the first two months, it will show up in the routine tests. It would appear that sperm present in the semen after 50 intercourses indicates recanalization, and reoperation should be considered. Intermittant aspermia may be due to a temporary blockage of a recanalizing vas. No third vas was encountered and it is probable that its functional existence is to provide the surgeon with a reason to give the patient for failure to attain sterility. It is unlikely and unethical that the auestion whether a patient with non-motile sperms in his specimen is capable of impregnationother specimens may contain motile spermatozoa-will be resolved as it is not in the interest of the patient, his wife, or the child to prove that the husband is not the father. If the doctor is not aware of this the patient and his wife are, and will refuse the confrontation and consequences.-I am, etc.,