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Tuesday, December 1, 2020

AZOOSPERMIA III: REPRODUCTIVE MICROSURGERY

AZOOSPERMIA III: REPRODUCTIVE MICROSURGERY

The role of microsurgery in the treatment of male infertility is well established and cost-effective when compared to assisted reproduction, including in vitro fertilization and intracytoplasmic sperm injection. Surgery also attempts to reverse specific pathology and, as such, allows for conception at home rather than in the laboratory. The rise of microsurgery as a surgical discipline followed three advances: (1) refinements in optical magnification, (2) the development of more precise microsuture and microneedles, and (3) the ability to manufacture smaller and more refined surgical instruments. In urology, microsurgery was first applied to renal transplantation and vasectomy reversal. Techniques evolved quickly from humble beginnings using borrowed forceps from the local jewelry store (the “jeweler’s forceps”) and using human hair for fine suture material, to its current highly refined state.

The most commonly performed microsurgical procedure in urology is vasectomy reversal. The most common reason for vasectomy reversal is remarriage and the desire for more children. Occasionally, an unfortunate individual will have chronic pain after vasectomy or have lost a child and desire another. Infection, congenital deformities, trauma, and previous surgery are less frequent indications for vasovasostomy or epididymovasostomy (see Plate 5-4). Reproductive tract obstruction is suspected in men with normal FSH and testosterone levels, normal testis size, and azoospermia.

AZOOSPERMIA III: REPRODUCTIVE MICROSURGERY


Vasal obstruction is generally corrected by vasovasostomy. Although there are several methods for performing vasovasostomy, including a modified single-layer anastomosis and a strict, two-layer anastomosis, neither is proven superior to the other. Importantly, optical magnification with an operating microscope improves outcomes as smaller sutures can be used, reducing cicatrix formation and failure rates. However, surgeon experience is the most critical factor for success. In the best hands, 95% to 99% of patients have a return of sperm after vasovasostomy.

At the time of vasectomy reversal, the vas deferens is transected below the vasectomy site. If the fluid egressing from the vas deferens contains no sperm, a second acquired obstruction may exist in the delicate tubules of the epididymis. As more time passes after vasectomy, the greater will be the “back-pressure” behind the blocked vas deferens, causing a “blowout” at some point in the 18-foot-long microscopic epididymal tubule. A blowout results in blockage of the tubule as it heals. In this case, the abdominal vas deferens must be connected to the epididymis proximal to the blowout to bypass both sites of obstruction and to reestablish reproductive tract continuity in a procedure termed epididymovasostomy.

For epididymovasostomy, the epididymis is exposed by opening the tunica vaginalis that surrounds the testis. The epididymis is inspected and an individual tubule selected that appears dilated and is proximal to the obstruction. Two different approaches to epididymovasostomy are now popular: the mucosa-to-mucosa end-to-side method and the invagination approach. With the traditional mucosal approach, the opened epididymal tubule is connected to the cut end of the vas deferens, with four to six small microsutures placed radially around the circumference of each. This “inner” layer is buttressed with another, “outer” layer of radially placed microsutures to strengthen the delicate connection. With the invagination method, one, two, or three “vest” microsutures are placed near but not into the opening of the epididymal tubule to allow the epididymal tubule to be drawn into, or “invaginated” into, the lumen of the vas deferens, theoretically creating an improved water-tight seal. After epididymovasostomy, approximately 60% to 80% of men will have sperm in the ejaculate.

In cases of idiopathic epididymal obstruction, a similar approach as that taken for vasectomy reversal is employed, except for an important difference. Because there is no iatrogenic blockage of the vas deferens with idiopathic obstruction, the fluid within the vas deferens is sampled from, and the vas deferens inspected by, vasography instead. After puncturing or hemitransecting the straight segment of the scrotal vas deferens, diluted dye or contrast medium is injected into the vas deferens toward the bladder from the scrotum. In plain-film radiographs, contrast delineates the proximal vas deferens, seminal vesicle, and ejaculatory ducts and the site of obstruction can be determined. In addition, the finding of no sperm in the vasal fluid from the testis side of the vas deferens implies that there is an obstruction present in the epididymis. With this information, the site of obstruction can be accurately determined and the system microsurgically reconstructed with either vasovasostomy or epididymovasostomy.


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