“Microsurgical Vasovasostomy: The Microdot Technique of Precision Suture Placement” (1998), by Marc Goldstein, Philip Shihua Li, and Gerald J. Matthews

By: Cole Nichols

In 1998, urologists Marc Goldstein, Philip Shihua Li, and Gerald J. Matthews published “Microsurgical Vasovasostomy: The Microdot Technique of Precision Suture Placement,” hereafter “The Microdot Technique,” in The Journal of Urology. The authors describe a novel technique for reversing a vasectomy, which blocks a patient’s flow of sperm, preventing the patient from fertilizing a partner’s egg. The technique relies on the placement of microscopic dots to guide the placement of the stitches that reconnect the vasa deferentia, which is a part of the male reproductive system. The authors, working from the Center for Male Reproduction and Microsurgery at Weill Cornell Medicine in New York City, New York, published the article to instruct surgeons on how to properly employ the surgical technique and provide data to indicate the technique’s effectiveness. Through the publication of “The Microdot Technique,” Goldstein, Li, and Matthews provide guidelines to conduct a more successful and accurate method of a vasovasostomy.

At the time of publication, Goldstein, Li, and Matthews were performing their research out of the Center for Male Reproduction and Microsurgery at Weill Cornell Medicine in New York City, New York. Weill Cornell Medicine is the medical college and research center associated with Cornell University, whose main campus is located in Ithaca, New York. As of 2023, Goldstein and Li continue to conduct research in urology, and practice urology, as well as working as professors at Weill Cornell Medical College. Matthews continues to practice urology and teaches at New York Medical College in Valhalla, New York.

People seek out vasectomies as a method of permanent contraception, though the procedure is reversible. A vasectomy involves some form of severing or blocking the vasa deferentia, also called the ductus deferens, which are two tube-like structures in the male reproductive system. The vasa deferentia are a focus of vasectomy because of their role in the transport of sperm, which can cause pregnancy through sexual intercourse. The testes, which hang in the scrotum below the penis, generate sperm, which then move into a connected vessel called the epididymis. From the epididymis, sperm next move through the vasa deferentia, which transport sperm from the scrotum up into the pelvis. The two vasa deferentia, which extend somewhere between thirty and forty-five centimeters from each testis, end and meet at an ejaculatory duct from which the sperm can be ejaculated out of the penis during sexual intercourse. The vas deferens has three main layers extending out from the lumen, the tubular space inside the vessel through which the sperm flows. The innermost layer, which surrounds the lumen, is the mucosa. The middle layer is the muscularis, consisting of muscular tissue. The final, outermost layer is the vasal sheath, which encapsulates the structure and contains certain blood vessels.

In a vasectomy, a surgeon makes a small incision on the scrotum, allowing access to both vasa deferentia. The surgeon then carefully takes the vasa deferentia out and uses one or multiple methods to block the flow of sperm through the duct. One such method is constricting the severed ends with a clip which clamps around the tube, closing it off. After getting a vasectomy, a person continues to be able to ejaculate semen, which is the fluid that typically contains sperm, but without transporting any actual sperm, making them sterile. People who have received vasectomies may choose to seek out a vasectomy reversal procedure for various reasons, such as deciding to try to have children again, or experiencing pain after a vasectomy. The two primary options for surgical vasectomy reversal are vasoepididymostomy and vasovasostomy. Both procedures restore the flow of sperm through the vas deferens to make the patient fertile again. In a vasoepididymostomy, a surgeon connects the severed section of the vas deferens coming from the abdomen directly to the epididymis, where the sperm usually enters an intact vas deferens. In a vasovasostomy, the procedure the authors of “The Microdot Technique” discuss, a surgeon cuts out the blocked portion of each vas deferens and reconnects the two cut segments of the tube. Surgeons typically perform vasoepididymostomies when they determine that a vasovasostomy would not be successful.

To perform a vasovasostomy, a surgeon stitches the two disconnected ends of each vas deferens back together. The surgeon passes the sutures into the lumen and pierces into the mucosal layer from inside the lumen. The suture then exits the tube at some point on the cut end of the vas deferens. There are various methods to perform a vasovasostomy, and some include a surgeon performing the reconnection with either a one-layer technique or two-layer technique. The one-layer technique uses only one layer of sutures to reconnect the whole vas deferens. Each suture will pierce through the lumen and secure all layers of the vessel. In the two-layer technique, the surgeon uses two layers of sutures to reconnect the vessel. The sutures still pierce through the same luminal area, but one layer of sutures will exit through the mucosal layer, the innermost layer, with the second exiting through the muscularis layer, the middle layer. When discussing the results of a vasectomy reversal, physicians take both patency and fertility into account. In the case of vasovasostomy, patency rate is the percentage of males who have sperm present in their semen after the procedure. For males, fertility is the ability to successfully fertilize a partner’s egg with sperm.

“The Microdot Technique” explains why the novel microdot technique is a more successful and accurate option for use in a vasovasostomy procedure to reconnect the severed ends of the vas deferens in comparison to other vasovasostomy techniques. The authors review clinical data from 194 vasovasostomies Goldstein performed using the microdot technique and find that the technique correlates with a higher fertility rate than other vasovasostomy methods. In addition to the statistical justifications for the procedure’s efficacy, the authors include a detailed set of instructions for the microdot technique. Through the instructions, the authors demonstrate how the technique physically provides a more secure reconnection of the vas deferens. The authors examined previous findings which linked a longer interval of time following a vasectomy to greater difficulty in performing a successful vasovasostomy.

The authors of “The Microdot Technique” divide the principal text of the article into four main sections. The first section is a brief introductory paragraph that includes statements of the physiological phenomena that the microdot technique is supposed to treat when microsurgically reversing a patient’s vasectomy. The second section titled “Technique,” has a detailed description of the surgical technique itself, which also functions as a guide for how a surgeon should perform the microdot technique. The third section titled “Results,” has a paragraph that includes descriptions of the authors’ results. They introduce trends of slightly increased patency and fertility in microdot vasovasostomies that Goldstein performed. The fourth and final section of the article, titled “Discussion,” is an analysis of the results in which the authors write to advance their claim that the microdot technique is a more effective and precise method when it comes to performing vasovasostomies.

In the introductory section of  “The Microdot Technique,” the authors outline the key factors of their research. They include that the data they refer to throughout the article comes from a study of 1,200 vasectomy reversal procedures. The authors use the study’s data to show a relationship between the length of time after a vasectomy and physical changes that make a vasovasostomy more difficult and less successful. In the group of vasectomy reversal patients that the authors studied, the average length of time between the vasectomy and the vasectomy reversal was seven years. After a vasectomy, the blocked ends of the vasa deferentia connected to the testicles cannot release the pressure buildup of sperm coming from the testes. The pressure from the buildup causes significant stretching in the lumen of the testicular end. The authors report that the stretched lumina can reach a diameter of up to one millimeter, as opposed to a typical unstretched lumen’s diameter of 0.3 millimeters. When the testicular end of the vas deferens has a lumen stretched to a size significantly greater than the unstretched abdominal end, matching up the two segments in a vasovasostomy becomes more difficult for the surgeon. Beyond difficulties in the operating room, the authors express that reconnecting the segments of the vas deferens in a way that does not completely seal the lumen of the vessel would result in substandard patency and fertility. They state that the novel microdot technique allows surgeons to accurately reconnect lumina of widely different diameters to provide the patient with a higher patency and fertility rate.

After introducing the problem that the authors intend the microdot technique to solve, they begin the “Technique” section of the article, explaining the setup necessary to properly employ the microdot technique. The authors’ specified surgical setup involves the surgeon and assistant seated on padded rolling stools so that their lower bodies are stable during surgery, and they are able to maneuver around the patient with relative ease. The authors also recommend what they refer to as arm boards, which should be set up on each side of the surgeon and assistant to stabilize their arms and ensure the greatest possible accuracy in the microscopic procedure. They add that a right-handed surgeon should sit at the patient’s right side so that their dominant hand is better available to perform the more difficult stitches on the abdominal end of the vas deferens.

The instructions for the procedure include references to five photographic or illustrated figures that depict important steps of the microdot technique. The first figure that the authors reference is a photograph of the cut ends of the vas deferens stained by a blue dye that allows the surgeon to better identify the mucosal layers of the vasa deferentia. The authors instruct the surgeon to dry the cut ends of the vas deferens and use a microtip marking pen to indicate where the sutures will exit the tissue of the vas deferens as they reconnect the cut ends. The surgeon makes eight equidistantly spaced microdot markings with the pen in a circle on the cut ends of the vasa deferentia. The authors describe the placement of the microdots in reference to the hours on a clock. Specifically, the dots placed at the three and nine o’ clock positions have an extended line as a reference point to guide the reattachment of the cut vas deferens. The authors’ second figure is an illustration of the two cut ends of the vas deferens marked with the microdots, along with a photograph during surgery, also depicting the placement of the microdots. The authors add that the use of the dots to plan where the sutures will go helps to lower the risk of a faulty reconnection.

Continuing in the “Technique” section, the authors state that double-armed sutures are the preferred option for surgeons to use in the microdot technique. Double-armed sutures have needles attached on both ends of the thread. The use of a type of suture with two piercing ends allows the surgeon to pass through both cut ends of the vas deferens with the same suture. The authors instruct the surgeon to pass four sutures through the vas deferens, each piercing through the luminal wall of the vessel and exiting through its own microdot on the vessel’s cut surface. Then, the surgeon adds three more sutures on the muscularis layer, above the mucosal layer, in-between the first four sutures, to eliminate any gaps between the previous sutures. The surgeon should then rotate the vas deferens to pass four more sutures through the four remaining microdots. The third figure included is an illustration of the two ends of the vas deferens connected by the first four sutures. The fourth and fifth figures are photographs showing the reconnection of the vessel in a real vasovasostomy case. At the end of reconnecting the mucosal layers, each of the eight sutures works to connect the luminal walls of the two ends to each other.

The authors instruct the surgeon to finish reconnecting the muscularis layer of the vessel with five additional sutures. They state that, at that point, the microdot technique should provide a watertight reconnection of the two segments. To finish the reconnection of the vas deferens, the authors instruct the surgeon to reconnect the sheath of the vessel with six to eight additional sutures. They state that reconnecting the sheath relieves tension on the sutures that hold together the inner structure of the vas deferens.

The “Results” section of the article contains the outcomes of a study of 194 vasovasostomy patients that showed that the microdot technique had high rates of success. All of the patients were given a vasovasostomy that used the microdot technique, and Goldstein performed all of the procedures. The authors specify that they only included patients with sperm detected at the testicular end of the vas deferens before surgery. They reported that all but one of the 194 patients exhibited patency after the procedure. At an average of seventeen months after the operation, out of the first one-hundred patients, fifty-four percent contributed to pregnancy with their partners. Overall, the authors reported a sixty-four percent pregnancy rate following the operation for the study’s patients. However, the overall pregnancy rate was calculated excluding couples whose infertility was due to the female partner, as those individuals were not affected by the vasovasostomy procedure.

The authors begin the “Discussion” by restating that, generally, a longer interval of time after a vasectomy leads to a greater difference between the diameters of the lumina on the disconnected segments. They describe how an unequal distribution of sutures for the two differently sized lumina leads to risks of gaps, leaks, or other deformities in the reconnected vasa deferentia. The authors go on to restate their claim that the microdot technique provides a method for surgeons to precisely map their sutures on the cut ends of the vasa deferentia. With the sutures’ specific locations planned, the surgeon should be able to avoid deforming the vas deferens and promote a watertight connection of the segments. The authors indicate that the microdot technique showed a slightly higher patency rate than other vasovasostomy techniques, reporting that ninety-nine percent of patients achieved patency with the microdot technique, and ninety-two percent of patients achieved patency with other vasovasostomy methods. Based on the patency data and the anatomical outcomes of the vasovasostomy with the microdot technique, the authors conclude by stating that the microdot technique is a method that improves the efficacy of vasovasostomy procedures.

As of 2023, according to Google Scholar, researchers have cited “The Microdot Technique” 149 times, and the use of the article extends from its publication in 1998 to multiple publications released over the two following decades. In 2021, Richard J. Fantus and Joshua A. Halpern, physicians researching male reproductive health out of Chicago, Illinois, at the time, published “Vasovasostomy and Vasoepididymostomy: Indications, Operative technique, and Outcomes.” The researchers refer to Goldstein, Li, and Matthews in their explanations of the advancements of vasectomy reversal techniques and how the microdot technique could be used along with the new techniques if there are differing sizes of luminal. Beyond solely being a technique that centers the surgeon, other researchers have investigated the microdot technique’s potential as a form of surgery conducted robotically. “The Microdot Technique” provided physicians with an improved and accurate method of performing vasovasostomies, which in turn restores fertility for those seeking it.


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Megha Pillai


Arizona State University. School of Life Sciences. Center for Biology and Society. Embryo Project Encyclopedia.


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