THE FIRST SEMEN ANALYSIS AFTER VASECTOMY: TIMING AND DEFINITION OF SUCCESS
Dhaval Bodiwala, 8 Scholars Walk, London Road, Leicester, LE2 1RR, UK. e-mail: firstname.lastname@example.org
semen analysis (after vasectomy)
Royal College of Obstetrics and Gynaecology
(random) nonmotile sperm.
Surgical sterilization is the principal method of contraception worldwide; ≈ 190 million women use tubal ligation as a contraceptive method, while 42 million men rely on vasectomy . Vasectomy fails in up to 2% of patients , the cause of which includes inadequate vasectomy, unprotected intercourse before the semen is azoospermic, and early and late recanalization. The aim of semen analysis after vasectomy (SAV) is to detect early recanalization, which is essentially a ‘technical failure’. By contrast, late recanalization is the persistent reappearance of motile sperm after initial clearance. Late recanalization causes failure in 0.2% of vasectomies .
In general, SAV is the accepted method for determining the success or failure of the procedure, but the exact protocol for SAV is not universal. Some physicians instruct patients to return the first SAV, based on an arbitrary number of weeks elapsed after vasectomy, the number of ejaculates, or both.
RECOMMENDATIONS FOR TIMING
Published recommendations differ widely for the timing in SAV protocols. All ejaculates contain potentially fertile spermatozoa immediately after vasectomy, which become immobile within a few days and usually by 3 weeks. The British Andrology Society guidelines in 2002 recommended that men wait 16 weeks for the first SAV and that they should have produced at least 24 ejaculates before this analysis . Clearance was possible if this SAV was azoospermic. The WHO published guidelines in 1988 and recommended one or two SAV after 12 weeks or 15 ejaculates . A systematic review of 56 studies was recently conducted to evaluate the time to azoospermia, the number of ejaculations needed to clear the vas deferens of sperm, persistent nonmotile sperm (NMS), recanalization and vasectomy failure . This review showed that the median incidence of patients with azoospermia was consistently >80% at 12 weeks and after 20 ejaculates. The authors recommended clearance if a single sample showed azoospermia at 12 weeks and after 20 ejaculates. In a British study, azoospermic rates for the first SAV were 98% and 97% for semen provided after 12 and 16 weeks, respectively . On this basis, the authors recommended clearance after one azoospermic sample at 12 weeks. Other physicians will only consider random NMS (RNMS) in the definition of clearance in men who have submitted multiple SAVs without successfully achieving azoospermia. The Royal College of Obstetrics and Gynaecology (RCOG) guidelines supports the use of ‘special clearance’ if there are <10 000 NMS/mL in a fresh specimen provided at least 28 weeks after vasectomy . The rationale for this recommendation was that no pregnancies have been reported in these patients at up to 3 years of follow-up [3,8].
Surveys have identified trans-Atlantic differences in SAV protocols; American physicians are more likely to routinely request one SAV before 12 weeks than their British counterparts. A survey in England showed that 5% of urologists routinely request one SAV, 90% two, and 5% three SAVs ; ≈ 99% requested submission of the first SAV by 12 weeks. By contrast, a survey of 1800 vasectomy practitioners in the USA found that 56% routinely requested one SAV, 39% two and 5% three or more SAVs .
After an audit at our hospital, we confirmed that men needing to submit a second SAV are less compliant. However, a caveat associated with instructing men to delay submission of their first SAV until after 4 months is that we found that they are also less likely to submit a semen sample. We identified 510 consecutive men who had had a vasectomy in 2000–2004. Following the publication by Sivardeen et al., which suggested simplifying the SAV follow-up to routinely requesting one SA at ≥ 16 weeks after vasectomy, we changed our follow-up protocol from one that asked patients to provide two SAVs at 12 and 16 weeks (before September 2002) to another requesting submission of one SAV at 18 weeks (from September 2002). For those providing two SAVs, submission rates for the second SAV were only 42%, compared with 73% for the first. Submission rates for first SAV were 66% after September 2002, compared with 79% before.
A wide range of SA protocols are used in the follow-up of patients after vasectomy. This perhaps reflects the conflicting published recommendations. Many men are not compliant with instructions, necessitating planned submission of multiple semen samples. Several published results suggest that a first SAV showing azoospermia is sufficient to grant clearance [4,6,7,9]. Although a protocol such as ours, which instructs patients to wait 18 weeks for the first SA, is cost-effective, some patients might consider waiting >4 months to be unreasonable, and indeed might either submit an earlier SAV or fail to submit a semen sample. One azoospermic SA first submitted at ≥ 12 weeks after vasectomy has now been recommended by several authors to be a marker of ‘vasectomy success’[6,7].
It is widely believed, if not practised, that the presence of RNMS only is consistent with a successful vasectomy. Although ‘special clearance’ can be considered for men achieving the RCOG guidelines for RNMS at ≥ 28 weeks after vasectomy, the granting of clearance to men who have RNMS in their first SAV submitted earlier is more controversial, and hence prospective studies are needed to assess the risk of late failure in these men. A prerequisite of preoperative counselling for vasectomy should be an understanding by the patient that vasectomy is not a procedure but a process requiring a SAV to determine success.
On the basis of published evidence, we recommend a single SAV at 12 weeks, because compliance is excellent and ≈ 80% of submitted semen samples are azoospermic. For those with detectable spermatozoa at 12 weeks after vasectomy, ≈ 95% will be azoospermic 6 weeks later, and so we recommend a second SAV for them at 18 weeks.
CONFLICT OF INTEREST