A New Reversible Male Contraceptive: Open-Ended Vasectomy and Microscopic Reversal
American Association of Zoo Veterinarians Conference 2005
Sherman Silber1, MD; Randall Junge2, DVM, DACZM
1Infertility Center of St. Louis, St. Luke’s Hospital, Chesterfield, MO, USA; 2Saint Louis Zoological Park, St. Louis, MO, USA


The open-ended vasectomy is a technique used in humans. Options for temporary contraception in males are limited, and the reversible vasectomy is the only currently available method that does not impact behavior. The key to ease of vasectomy reversal is allowing sperm to leak from the distal end and form a pressure-relieving granuloma, yet at the same time sealing the proximal end securely enough (through needle cautery) that spontaneous recanalization with failure of the vasectomy does not occur. This latter technique prevents the buildup of pressure in the testis, thereby preventing damage to the male’s reproductive capacity. This technique and the microscopic reversal of this surgery are associated with 90% reversal success (i.e., ability to impregnate partner post-reversal surgery) in humans.1

Open-Ended Vasectomy Procedure

The typical midline incision used in neutering and vasectomy procedures is not used as this technique results in difficulty in freeing the proximal end of the vas deferens during the subsequent reversal procedure. With a scalpel and the aid of vasectomy clamps, the vas can be isolated from the cord via a small incision in the upper scrotum or at the external inguinal ring. In humans, the incision is always less than 3 mm in their very thin scrotal sac skin. In many other animals, however, the thickness of the scrotum precludes this approach and it is best to make a 1–1.5 cm incision over the external inguinal ring. The vas is exposed and transected, and the abdominal (proximal) cut end of the vas deferens is cauterized by inserting a needle electrode about 1 cm internally. If only the mucosa is cauterized, and the muscle is unharmed, a very tight seal will form. Do not cauterize or ligate the scrotal (distal) cut end of the vas deferens; the distal end is left open to leak and release pressure.

Microscopic Vasectomy Reversal Procedure

Using a scalpel, make an approximately 5 cm (total length) incision over scrotum (2.5 cm) and extend over to groin (2.5 cm). Bluntly dissect the vas deferens (longitudinally) with blunt nose small scissors (e.g., iris scissors). Free the vas deferens and place a small Penrose drain underneath to facilitate dissecting it from the cord. Free the vas deferens ends and secure the ends with vasovasostomy clamps. Resect the scarred ends of both sides of the vas deferens. Aspirate translucent fluid from the distal cut end and check for the presence of sperm. Absence of sperm indicates that there is epididymal blockage, and vasovasostomy therefore cannot work. Vasovasostomy is completed with 9-0 nylon interrupted sutures, three in the mucosa and six in the muscularis.

We now are recommending that surgery be performed not as in humans (through the scrotum), but rather at the external inguinal ring. This will allow easier exposure of the vas, and avoid possible damage to the delicate scrotal blood supply. Also, we do not believe that an operating microscope is necessary for the microsurgical vasovasostomy; it would be easier and far less expensive to use high-power loupe magnification for this. However, without the open-ended vasectomy, with subsequent epididymal obstruction, an operating microscope would be absolutely mandatory.

Literature Cited

1.  Silber, S.J., and H.E. Grotjan. 2004. Microscopic vasectomy reversal 30 years later: a summary of 4010 cases by the same surgeon. J Androl. 25(6):845–859.


Speaker Information
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Randall Junge, DVM, DACZM
Saint Louis Zoological Park
St. Louis, MO, USA

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