Microsurgical Vasoepididymostomy

Introduction

In the past 5 to 10 years, very few fields in modern medicine have changed as dramatically as reproductive medicine, especially, for the treatment of male infertility. These advances include in-vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI) (injection of a single sperm into an egg), refined microsurgical reconstructive techniques (vasovasostomy and vasoepididymostomy), and microsurgical techniques of surgical sperm retrieval from the epididymis and testis. All men with epididymal obstruction now have the opportunity to father their own biological children.

What is the epididymis?

The epididymis is a tightly coiled (15 foot long if uncoiled) tube behind the testis where sperm go after leaving the testicle. It is basically a swimming school for sperm. Testicular sperm are unable to swim or fertilize an egg naturally, and acquire these abilities as they pass through the epididymis.

The diameter of the epididymal tubules is only 200 microns (twice the diameter of a human hair) which is how 15 feet of length can fit into a structure about half the size of the pinky. After leaving the epididymis, sperm empty into the vas deferens, which transports the sperm to the ejaculation ducts, which empty into the urethra in the penis.

What is the vasoepididymostomy?

Vasoepididymostomy is the microsurgical procedure for treatment of epididymal obstruction. It is the most difficult and technically challenging microsurgical procedure for the treatment of male infertility. Surgeons must have excellent microsurgical skills and extensive experience to be able to perform this anastomosic procedure between the vas deferens and epididymis.

What is the etiology of epididymal obstruction?

• Congenital abnormalities: absence of the distal part of the epididymis (cauda) with absence of the vas deferens.
• Young's Syndrome.
• Infection or inflammation: history of epididymitis (tuberculosis or chlamydia).
• Iatrogenic injury: accidental injury from prior surgery such as hydrocele repair, orchiopexy (for undescended testes or torsion), or testis biopsy.
• After vasectomy.

What are the advantages of vasoepididymostomy (VE) versus IVF-ICSI?

The advantages of the vasoepididymostomy for treatment for the epididymal obstruction are:

• Patients can father their own children through natural intercourse.
• In vitro fertilization (IVF) with ICSI is a very intense procedure for the female partner and very costly. Also, conception through natural intercourse does not pose ethical issues and it minimizes the risk of multiple births substantially.
• Return of sperm rates (52% to 92%) and pregnancy rates (11% to 56%) are competitive with IVF/ICSI.
• If an experienced surgeon performs the microsurgical procedure, the results (patency rate and pregnancy rates) are better than IVF.
• The actual overall cost per live baby is lower for VE than with IVF-ICSI.
• Insurance companies usually cover the expense for correction of an epididymal obstruction but usually not for IVF/ICSI.
• Sperm can be collected during the procedure and frozen (cryopreserved) for future IVF/ICSI attempts if the microsurgical procedure fails. 

Physical Examination and Laboratory Tests:

Physical examination of men with epididymal obstruction may reveal a somewhat enlarged, indurated epididymis. Men with epididymal obstructions are typically azoospermic (zero sperm count) and have normal semen volume. Normal serum follicle-stimulating hormone (FSH) levels and normally sized testis with epididymal fullness suggest normal sperm production. A highly positive blood antisperm antibody test confirms sperm production and eliminates the need for a testis biopsy to confirm obstruction.

Surgical Indications:

The indication for recommending and performing a vasoepididymostomy is the presence of active spermatogenesis (sperm production) in the testis, evidence of an epididymal obstruction and a patent (open) vas deferens. A general anesthesia or regional (continuous epidural block) is preferred when performing a vasoepididymostomy.

Testis Biopsy:

A testis biopsy is only necessary to confirm normal sperm production when blood FSH is normal, testis size is normal and a blood antisperm antibody test is negative. . Testicular biopsy performed using an operating microscope allows identification of subtunical blood vessels and reduces operative morbidity. Bouin's solution, the most widely used fixative, minimizes distortion of the testicular architecture. Other options include Zenker's solution or buffered glutaraldehyde, which are used when electron microscopy is desired.

The surgeon must be comfortable in assessing biopsy slides to make a clear plan of action based on the results. The patient with normal spermatogenesis should have in the range of 20 mature spermatids per round tubule, whereas the patient with epididymal obstruction typically should have at least 30 mature spermatids per round tubule. Alternatively, a squash preparation can be performed at the time of reconstruction to assess for the presence of sperm. This procedure involves placing a small piece of testis on a slide, with a drop of Ringer's lactate; the specimen is then compressed under a glass coverslip. This wet preparation is examined for the presence of sperm using a high, dry (40 X) objective lens. After it has been established that active spermatogenesis is present, a reconstruction can be undertaken at the time of biopsy or at a later date. Sperm can also be aspirated at the time of biopsy for use for IVF/ICSI.

Vasography:

It is also important and necessary to ensure that no other sites of obstruction are present within the genitourinary tract.

This is accomplished by performing a vasogram at the time of the vasoepididymostomy. The vas is isolated at the junction of the straight and convoluted portions. Under an operating microscope, the vasal sheath is vertically incised and the vasal vessels carefully preserved. Clean segment of bare vas is delivered, and a straight clamp is placed beneath the vas to act as a platform. The vas is hemi-transected with a 15° microknife until the lumen is revealed; the vasal fluid is examined for presence of sperm. The absence of sperm in the vasal fluid confirms epididymal obstruction. The seminal vesicle end of the vas is then cannulated with a 24-gauge angiocatheter sheath and injected with Ringer's lactate to confirm patency. If the Ringer's lactate passes easily, formal vasography is not necessary. If any doubt of the patency exists, 50% diluted indigo carmine dye may be injected and the bladder catheterized. The presence of blue dye in the urine confirms patency of the vas. If obstruction is suspected based on the Ringer's lactate and indigo carmine findings, then the site of obstruction is determined with formal vasography (use water-soluble radiographic contrast medium).

Surgical Preparation & Examination of Vas Deferens and Epididymis:

The vas is exposed at the junction of the straight and convoluted portions and the vas deferens is opened. Vasal fluid is sampled. The presence of sperm in the vasal fluid signifies proximal vasal or ejaculatory duct obstruction and a vasogram is performed. If no sperm is found in the vasal fluid it means epididymal obstruction. Occasionally copious amounts of clear fluid without sperm are encountered. If no clear site of epididymal obstruction exists, a vasovasostomy should be performed. The tunica vaginalis is incised and the testes delivered. The epididymis is carefully visualized and palpated. Often a granuloma or area of relative induration above which dilated tubules are seen is present.

The incision and exposure for the vasoepididymostomy proceeds as with a vasovasostomy. It is performed to bypass the site of epididymal obstruction.

References:

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