Microsurgical Vasovasostomy

Vasovasostomy is a microsurgical procedure to restore fertility after vasectomy, a surgery that sterilizes the patient by severing the vasa deferentia, the tubes that carry the sperm from the testes to the penis. After a vasectomy, a patient may have various reasons for wanting to reverse the procedure, such as new opportunities for having children or a new romantic partnership. A vasovasostomy involves reestablishing the flow of sperm through the vas deferens by reconnecting the severed ends of the tube. In 1919, in the United States, William C. Quinby performed the first recorded successful vasovasostomy. Modern improvements on the surgery have led to its adoption as a microsurgery, a procedure that involves a microscope and specialized microscopic instruments. Surgical research over the twentieth century into reconnecting a blocked vas deferens and the resulting microsurgical technique for vasovasostomy has provided a way for people to regain their fertility after a vasectomy.

The vasa deferentia are the focus of procedures meant to both sterilize patients and promote their fertility because of their role as transport tubes for sperm. The testes, which hang outside of the abdomen in the scrotum, generate sperm. Sperm travel through the epididymis, a series of tubes and ducts directly connected to the testis, singular of testes, to the vas deferens. The vas deferentia are tubes that usually extend to a length between thirty and thirty-five centimeters, beginning in the scrotum at the epididymis, the duct containing the sperm, and ending at the ejaculatory duct inside of the pelvis. The junction with the ejaculatory duct is where the two vasa deferentia, one vas deferens extending from each testis, meet. During ejaculation, layers of smooth muscle tissue surrounding the vasa deferentia propel the sperm from the testes to the penis.

Vasectomy is a method of long-term contraception in which a surgeon opens the scrotum via incision or puncture to access each of the vasa deferentia. Once the vas deferens is exposed, the surgeon is able to interrupt the flow of sperm through several different means. Ligation and excision is the name for tying off a small segment of the exposed vas deferens and removing it. In addition to ligation and excision, some surgeons add a step called fascial interposition. In fascial interposition, the surgeon, after having severed the vas deferens, pulls the vasal sheath of one end over the other, promoting the patient’s sterility and lessening the need to remove tissue from the scrotum, the sack that contains the testes. Rather than using ligation and excision, some surgeons choose to cauterize, or burn, the vas deferens, blocking the flow of sperm with scar tissue.

Because a vasovasostomy has the goal of reconnection between disconnected segments of the vas deferens, the surgeon must interact with the different layers of tissue that make up the tubes. A vas deferens is composed of three main layers surrounding the lumen, which is the cavity or channel within the tube through which sperm travel. The innermost layer, which directly surrounds the luminal space is the mucosa, a moist inner lining of the luminal space. The mucosa surrounded by the muscularis, a smooth muscular layer which propels the sperm during ejaculation. The outermost layer, which surrounds the muscularis, is the vasal sheath. The sheath contains the veins and arteries that supply blood to the rest of the vasal tissue.

In the US, as of 2022, vasectomy is a commonplace procedure for male sterilization. A 1995 survey from the Centers for Disease Control and Prevention, EngenderHealth, and the Tulane University School of Public Health in New Orleans, Louisiana, reported 500,000 vasectomies performed in the US that year. The National Survey of Family Growth estimated that between 1998 and 2002, between 175,000 and 354,000 patients had undergone vasectomies in the US each year. Some patients change their minds about needing contraception for a variety of reasons. Those reasons could include a change in marital status, the death of a child, or changes in life circumstances. After a vasectomy, it is possible to retrieve viable sperm from the testes or epididymis to use for artificial insemination. However, the cost of artificial insemination procedures can be prohibitive, so patients seek out vasectomy reversals to regain their abilities to cause pregnancy through sexual intercourse. Estimates of the rates of patients seeking a reversal post-vasectomy vary across the literature, but the rate falls between two and eleven percent of people who have received vasectomies.

The vasovasostomy procedure, the rejoining the severed vas deferens, came as a consequence of the use of vasectomy. Researchers began investigating the anatomy and diseases of the vasa deferentia in the 1800s, and surgeons began performing vasectomies for the purpose of sterilization by the end of the century. In 1948, Vincent O’Conor, working in the US, published a report on the use of vasovasostomy to restore fertility. In the report, he states that, in 1919, he assisted, William C. Quinby, in performing the first successful vasovasostomy on a human. O’Conor reported that the patient had chosen to undergo a vasectomy eight years prior and that he was able to confirm the success of the procedure due to twenty-five years of routine examinations with that patient. O’Conor’s report also contained the results of a questionnaire for urological surgeons, indicating that, at the time, the procedure succeeded in reconnecting the vas deferens in between thirty-five and forty percent of cases.

Vasovasostomy is one of two options for restoring the flow of sperm and fertility. The other option is vasoepididymostomy, a procedure where a surgeon reconnects the upper, abdominal segment of the vas deferens directly to the epididymis. Vasoepididymostomy primarily differs from vasovasostomy in that the surgeon bypasses the testicular segment of the vas deferens in favor of a direct connection between the abdominal vas deferens and the epididymis. The choice between vasovasostomy and vasoepididymostomy is up to the surgeon before or during the operation based on which method will provide the greatest flow of sperm after the operation.

Vasoepididymostomy came about in the early 1900s due to research into fertility issues. At the University of Pennsylvania in Philadelphia, Pennsylvania, in 1902, Edward Martin performed the first reported successful vasoepididymostomy. While studying the causes of sterility in the male reproductive system, Martin found that severing and reconnecting blocked tubes, such as the epididymis and vas deferens, allowed a patient to become fertile again. Martin used the procedure to restore sperm flow through the vas deferens for a patient who suffered an obstruction in the sperm’s pathway due to inflammation of the epididymis. He reported a patency rate, or the rate of ability to transport sperm through the vas deferens, of sixty percent of the typical rate after the procedure. That means that the vasoepididymostomy allowed for sixty percent of sperm transport through the vas deferens compared to a vas deferens not previously severed.

The vasovasostomy procedure transitioned into a microsurgery after two independent publications came out in 1977. Earl Owen, working in Sydney, Australia, published his findings in June of that year. In November, Sherman Silber, working in St. Louis, Missouri, echoed Owen’s findings. Both emphasized the importance of avoiding additional inflammation in the vas deferens from the surgery since that could impact sperm flow through the tube. Silber, in particular, noted that a greater length of time after undergoing a vasectomy could make the procedure more difficult due to changes in the shapes of the two segments of the vas deferens. The microsurgical elements of vasovasostomy found later refinement with Marc Goldstein, working in New York City, New York, who published a method of more complex suturing in 1998. Goldstein’s method directly addressed Silber’s earlier concerns about the time between vasectomy and vasovasostomy causing a more difficult procedure.

A modern microsurgical vasovasostomy requires a number of specialized instruments due to its focus on a highly specified area of the patient’s anatomy and due to its practice as a microsurgery. An operating microscope is necessary for the procedure. The operating microscope focuses a lens on the scrotal tissue and carries that image to an eyepiece. The surgeon can look into the eyepiece while sitting upright. In an upright seat with armrests, the surgeon can avoid fatigue from standing and tension in the hands and arms, which allows the surgeon to operate more effectively for longer periods of time. If the surgeon chooses to enter the scrotum through an incision, a scalpel is necessary to cut into the skin. Alternatively, if the surgeon chooses to enter the scrotum via the no-scalpel method, they need a sharpened set of curved grasping forceps to puncture the skin and a ringed clamp to grasp the vas deferens through the skin.

In addition to the tools necessary to situate the surgeon and access the interior of the scrotum, the procedure calls for another clamp to secure the exposed vas deferens and an extremely sharp surgical knife. The surgical knife allows the surgeon to cut through and remove the blocked section of the vas deferens, leaving them with two clean ends to reconnect. Also necessary for a vasovasostomy is a tool that aligns the two ends of the vas deferens for reconnection. Typically, surgeons use an approximator clamp, a set of two clamps with grasping rings aligned with one another, to line up the disconnected segments of the vas deferens. To reconnect the segments of each of the vasa deferentia, the primary mechanical goal of a vasovasostomy, the surgeon needs sutures and needles.

The patient lies on their back during the operation. The surgeon sits over the scrotum looking into microscope eyepiece. Typically, the surgeon places the patient under general anesthesia so that the patient is unconscious for the duration of the surgery. The primary reason for applying general anesthesia is to keep the patient as still as possible during complex repairs to the vas deferens. To begin the operation, the surgeon either makes an incision with a scalpel into the scrotum or punctures the scrotal skin with the pointed grasping forceps. The surgeon opens the scrotum between the testes and the base of the penis. Incision size can vary depending on the surgeon’s preferences, but a standard size is one centimeter in length. The surgeon may make a single incision puncture near the middle of the upper scrotum, or two incisions or punctures on each side of the upper scrotum. For a single point of entry, the surgeon brings both vasa deferentia through the same opening. For two points of entry, the surgeon brings each one of the vasa deferentia through the opening on its respective side of the scrotum.

Once the surgeon brings the vas deferens into view, they cut out the blocked segment of the tube. The process ends with two open-ended segments of the vas deferens with each face cut at ninety degrees. The perpendicular incisions into the vas deferens allow for greater ease in directly reconnecting the segments to one another. The surgeon then inspects both open ends of the tube for signs of a healthy vas deferens including bleeding and a smooth muscularis, the layer outside of the mucosal layer. The surgeon tests the abdominal segment of vas deferens to ensure that it can carry fluid through it and that there is no remaining blockage. They perform the same check for the testicular segment of the vas deferens, which involves making sure that moving sperm are present at the testicular end. If the surgeon can detect no sperm, or if the visible sperm do not move as quickly as they should, the surgeon will likely opt to perform a vasoepididymostomy instead.

There are three main methods for reconnecting the two segments of the vas deferens once they have been exposed and tested for sperm presence and transport ability. In the simplest method, called the one-layer technique, the surgeon uses a suture to pass through and secure all layers of the vas deferens at once. Only using one suture for multiple layers of the duct requires less microsurgical training. It does not include considerations for the lumina of the two ends not mechanically matching each other. Not accounting for mismatching luminal spaces can lead to lower patency due to the possibility of gaps between the segments of different sizes or positions. It is possible for sperm to leak out through the gaps, resulting in lower patency.

The second, more complicated, method for reconnecting the vas deferens, called the two-layer method, requires the surgeon to place two layers of sutures to connect the ends of the vas deferens. The inner layer of sutures goes through the mucosal layer of the duct, and the outer layer of sutures goes through the muscularis layer. In theory, the two-layer method can lead to higher patency than the one-layer method. The increase in efficacy is because the lumina of the vessels match more closely with one another by the inner mucosal layer of sutures. That is because the inner layer of sutures should avoid any gaps in the reconnection that allow sperm to leak out.

The third, most complicated, method of vasovasostomy is the microdot multilayer technique, which Goldstein described in 1998. The surgeon uses a microtip marking pen to make six equidistant dots surrounding the lumen. They place the dots at approximately one-third of the distance between the lumen and the outer end of the muscularis layer. Each dot then receives one suture to bring the lumina toward each other lined up as exactly as possible. The surgeon then adds a second layer of sutures in the deep part of the muscularis layer. The second layer has a greater diameter than the first layer, and the placement of its sutures lines up with the gaps in the sutures of the first layer. The surgeon then adds a third layer of sutures to close the outer muscular layer, lining the third layer up with the gaps in the second. Finally, they add additional sutures to close the outermost vasal sheath. Together, the four layers of sutures create a fit between the two segments of the vas deferens that is as watertight as possible. The spread of sutures throughout the tube’s layers distributes the tension more evenly on the different layers of the duct so that the innermost mucosal layers do not experience excessive tension.

Once the surgeon reconnects the vasa deferentia of both testes, they can close the incision or incisions. If the vasovasostomy relied on incisional entry, the surgeon usually applies sutures to the scrotal skin to close the surgical wound. If the surgeon used the no-scalpel technique to access the vasa deferentia, the wound can shrink and heal without further manipulation. The surgeon can discharge the patient immediately following the operation, instructing them to wear support on their scrotum for six weeks. The patient should avoid heavy physical activity for two weeks and can begin to resume sexual activity after four weeks. For the first six months after the procedure, the patient needs to submit semen samples every two months. Analysis of the samples will provide insight as to the success of the vasovasostomy and the ability to effectively inseminate a sexual partner.

Of the thousands of people who undergo vasovasostomy procedures every year, between seventy-five and one hundred percent of them show patency after the surgery, indicating that they are fertile again. From the patency rates, a range between forty-five and seventy-three percent of couples are able to achieve pregnancy after a vasovasostomy. After over a century’s worth of development and technical improvement, microsurgical vasovasostomy is a primary option for helping patients with male reproductive systems to regain their fertility.