Info - Success Rates

This is probably the most common misunderstanding among patients who are researching vasectomy reversals.  When a person comes in for a vasectomy reversal, it is not known until surgery begins whether that person would need a vasovasostomy only or an epididymovasostomy.  In looking through our data, approximately 10% of men ended up needing an epididymovasostomy on both sides, while about 20% needed an epididymovasostomy on one side only.  

This is important because if a man needs an epididymovasostomy, and you only do a vasovasostomy, it will not work.  That means that if you choose to do surgery with vasovasostomies only, 70% of the time, you will be just fine (good success rate).  But in 30% of cases, you will have a lower rate than you would have, had you chosen an option where you can do epididymovasostomies and vasovasostomies.  

It's notable that the majority of surgeons offering vasectomy reversals only perform vasovasostomies.  There are relatively few who perform epididymovasostomies in the US, and even fewer who perform them in the office.  

It's also notable that the far majority of online reported success rates are ONLY reporting men who had the simple repair on both sides.  We feel that this is misleading.  Since it is not possible to predict whether or not you will need an epididymovasostomy until the time of surgery, it is misleading to only report success rates of those who had vasovasostomies on both sides.  

If you are looking to have a vasectomy reversal performed, and you wish to have the best outcomes possible, it is important to choose an option and surgeon that includes an epididymovasostomy if needed.

The ReVas (REinforcing VAsal Suture) technique was developed by Dr. Landon Trost in 2018 to improve vasectomy reversal outcomes.  The technique and outcomes are described in greater detail on the ReVas page (details).  In brief, the new technique resulted in a higher percentage of men achieving success, higher sperm counts, and higher pregnancy rates 8.1x more likely).  Dr. Trost and Josh Savage were the first to perform the technique, were the only team performing the technique as of October 2019, and have the most experience with the technique.  

The success rate for a vasectomy reversal depends on several factors:

  • Definition of success
  • Whether a simple (vasovasostomy) or complex (epididymovasostomy) is performed
  • Time since vasectomy
  • Partner's age and fertility status

Each of these is described in greater detail below.

Probably the most important factor in determining whether a reversal is successful is how you define success.  By far, the most common definition that is used on websites and in scientific publications is "patency."  This means that at least one sperm was seen at some point following the reversal.  The issue with this definition is that it does not accurately capture what truly successful means.  A recent scientific publication identified that the true number needed to optimize chances for pregnancy is 5 million sperm per milliliter or more.(1)  In that particular publication, the authors indicated that those who had <5 million/ml had a roughly 15% chance of achieving a pregnancy compared to 63% in men with 5 million or more.  Interestingly, those who had even higher counts did not have an increased chance for pregnancy compared to the men who had 5 million or more. 

Another issue with definitions for success is that they often indicate sperm "at any point" but do not necessarily mean sperm at the most recent time point.  This can be a problem, as in some cases, the area that was sewn back together can sometimes close down 3-12 months after the original surgery.  So, even if an individual had 10 million sperm at 3 months, if they have 0 sperm at 6 and 12 months, it would still be considered a success by most definitions. 

Many providers will also define success based on certain patient factors.  For example, some will only include results from men who ended up having simple repairs on both sides.  The problem with quoting statistics in that way is that you will not know what repairs are needed until the time of surgery.  In those cases, although the numbers are technically accurate, in reality they are misleading since most patients will assume that these are referring to all-comers and not only to specific cases.    

One other pitfall which many patients will encounter is when providers quote "published" success rates rather than their own true rates.  Unfortunately, simply asking providers if these numbers represent their own rates will not always elicit a fully honest response, and there are no guideline or accrediting bodies that verify quoted results.  To avoid this pitfall, patients should be able to request the provider's most recent 30-50 cases at any time and review results themselves.  If the provider is not able to provide these numbers, then any quoted success rates should be viewed with some skepticism. 

With the above details in mind, it is not surprising that so many providers will quote 95+% success rates despite the fact that pregnancy rates are often far lower.  For the above reasons, we have elected to define "success" as 5 million sperm per milliliter or more at 1-year post reversal.  We feel that this most accurately captures what a true "success" would be. 


1 - Majzoub A, et al: Vasectomy reversal semen analysis: new reference ranges predict pregnancy. Fertility and Sterility. 2017 Apr;107(4):911-915.

In general, success rates with complex repairs (epididymovasostomy) are significantly lower than simple repairs (vasovasostomies).  This is probably due to several factors including the risk of the area pulling apart post-operatively, lack of viable dilated epididymal tubules, smaller volume of fluid that passes through the anastomosis, or other factors.  Because of this, men who are able to have a simple repair on both sides are much more likely to have a successful outcome than those who have a complex on both sides.  However, as noted above, it is not possible to know if you will need a simple or complex repair until the time of surgery. 

The time since vasectomy may or may not have a significant role in predicting success rates.  For many years, it was believed that the time since vasectomy was a key factor in predicting whether or not a reversal would be successful, with decreasing success rates noted among men who were further out from the reversal.(1)  However, other publications have disputed this finding.  In reviewing our own data, we have found that prior to our implementation of the ReVas technique, the time since the vasectomy was a predictor of success rates.  After we began performing the ReVas technique though, it was no longer an important predictor.  Because of this finding, we believe that if the repair is sufficiently robust, the time since reversal is no longer a key predictor of success rates.    


1 - Mui P, et al: The need for epididymovasostomy at vasectomy reversal plateaus in older vasectomies: a study of 1229 cases. Andrology. 2014 Jan;2(1):25-9.

Partner age will not impact whether or not sperm may be present after a vasectomy reversal.  However, it may impact the chance of achieving a pregnancy. 

The true definition for success of a reversal is whether or not a couple was able to achieve a live birth.  However, this definition is not perfect for determining whether or not a reversal was successful since it includes partner factors as well.  For example, female fertility will generally decline beginning at age 35.  Additionally, up to 15% of couples are unable to achieve a pregnancy, even when the male partner has not had a prior vasectomy.  Even in couples where both the male and female have achieved pregnancies previously, in some cases, they will not be able to achieve a pregnancy together.  So, for these reasons, pregnancy is not an ideal measure of success. 

Vasectomies can fail for several reasons including:

  • The two ends pulling apart
  • Wrong surgery performed
  • Poor surgical technique
  • Post-operative scarring or complications

Each of these factors are described in more detail below.

The most common reason for failure is the two sewed ends pulling apart.  There are many activities which put strain on the vas deferens.  Although this list is not comprehensive, the following activities pull on the vas and can increase the risk of failure: arching your back, reaching up high, twisting, bending, performing lunges, coughing, sneezing, tightening your stomach muscles (such as is needed to lift something), penetrative intercourse, and jogging, among others.  You will want to limit any of these activities for up to 8 weeks after surgery to avoid pulling the repair apart.

Another reason reversals fail is that the correct surgery was not performed.  To give you the best chances for success, you will want to make sure that your surgeon regularly performs complex repairs (epididymovasostomies).  Unfortunately, it is not possible to know if you need a simple (vasovasostomy) or complex (epididymovasostomy) repair until the surgery has started.  So, if the surgeon is only able to perform simple repairs (common among surgeons performing the repair in the office), then the chance of failure increases.

Surgical technique is also very important to assure success.  The surgeon should utilize an operating microscope (not surgical loupes) to perform the surgery.  Also, fluid should be sampled intra-operatively to determine if a simple (vasovasostomy) or complex (epididymovasostomy) repair is needed.  Although there is some debate about this, most established vasectomy reversal specialists recommend the use of fine sutures (10-0) to help reconnect the tubes.  And as has been recently reported, a new technique (ReVas) increases all measures of success (sperm counts and pregnancy rates). 

In some cases, although the surgery was performed appropriately, the tubes that were connected later scar down.  This can result from resuming strenuous activities too soon after surgery, the wrong surgical technique (ReVas reduces this), complications, or due to unknown causes. 

If a reversal fails, the options for a biological child are:

  • Repeat reversal (typical success rates ~60%)
  • In-vitro fertilization

            If the reversal is unsuccessful, couples have the option of redoing the reversal or undergoing assisted techniques such as in-vitro fertilization or intracytoplasmic sperm injection.  The success rates for a repeat reversal will depend on the experience of the first surgeon and what surgery was performed (simple vs complex repair).  Also, it is important to determine if sperm are present.  If the couple hasn't achieved a pregnancy, but there are large numbers of sperm present in the ejaculate, then it is likely that the initial reversal was successful and that other factors are preventing the pregnancy. 

            In-vitro fertilization / intracytoplasmic sperm injection may also be performed depending on the female partner's age.  Success rates with IVF/ICSI are typically 40-45% live birth rate at 35 years of age, 5% by 40 years, and 0% by 45 years per cycle.  So, female age often plays a significant role in this decision. 

            It is also possible to undergo both a reversal and IVF/ICSI.  This ultimately gives the highest chances for a successful live birth, however, this is also the most expensive option and is therefore often not pursued by couples. 

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