Influences on the success of vasectomy reversal
There are several factors which influence the results of vasectomy reversal surgery. The most important in determining the number and quality of sperm present after surgery are the nature of your prior vasectomy, the degree of testicular damage following vasectomy and whether or not you have undergone prior sperm extraction procedures for IVF. Your partner's age is by far, the dominant influence on the overall chance of having a healthy baby following vasectomy reversal.
Type of vasectomy
There are numerous ways of performing vasectomy and generally the type of vasectomy has only a minor influence on reversibility. If however, the vasectomy site is close to the testis or a large segment of vas deferens has been removed this can lead to damage the epididymis and make vasectomy reversal more difficult to perform - leading to the need to undertake a vaso-epididymostomy (joining vas deferens directly to epididymis).
Following vasectomy there is usually some evidence of microscopic damage to the testes. This may have the effect of lowering post vasectomy reversal sperm count or sperm quality and consequently pregnancy rate. While the degree of testicular damage correlates closely with post operative pregnancy rates, it is impractical and generally unhelpful to perform testicular biopsies at the same time as vasectomy reversal as doing may increase complication rates without enhancing success rates.
IVF sperm extraction
When prior sperm extraction procedures have been performed to obtain sperm for IVF prior to vasectomy reversal, patency rates (the presence of sperm) are significantly reduced. The procedures are epididymal sperm aspiration (PESA), testicular needle aspiration (TESE) and open testicular biopsy.
When bilateral PESA procedures have previously been attempted post-vasectomy reversal patency rates are less than 30% and when unilateral are approximately 70% to 80%. This is because the epididymis is a highly convoluted tubular structure which is a continuation of the internal lining of the vas deferens (minus the latter’s muscular coat). As the epididymal tubule’s diameter is considerably less than that of the needle used for PESA, damage to and subsequent obstruction of the epididymis is likely. For TESE the negative effect is somewhat less with patency rates between 80% and 90%. The reason for these detrimental effects is outflow obstruction as consequence of inadvertent collateral damage to the intra-testicular collecting system (rete testis), post procedure fibrosis consequent upon both multiple passes of the aspirating need through the testis or resolution of intra-testicular haematoma. A small open incisional biopsy of the testis is unlikely to have a similar negative effect.
The American Society of Reproductive Medicine no longer recommends testing for sperm antibodies prior to vasectomy reversal as the results are neither sufficiently unreliable nor specific in predicting who will and who won't have fertility restored following surgery
Ultrasound is a very poor predictor of successful vasectomy reversal. The American Society of Reproductive Medicine does not recommend its use prior to vasectomy reversal as the results are generally misleading.
Female age is the single most important factor influencing pregnancy rates and take home baby rates following vasectomy reversal with the younger your partner the higher the chance of successful pregnancy. The reason for this is that women are born with all the eggs (oocytes) they will ever produce. Eggs are held in a state on incomplete cell division up until just prior to ovulation. Over time they they are vulnerable to undergo abnormal cell division leading to an uneven separation of chromosomes (intracellular structures which carry genes). This leads to an increasing number of abnormal eggs with age, decreasing pregnancy rates as well as increasing miscarriage and congenital abnormality rates.
If your partner has a history of serious gynaecological problems such as fallopian tube infection, endometriosis or damage to her ovaries this may reduce pregnancy rates following vasectomy reversal.