Материал: Oxford American Handbook of Urology ( PDFDrive )

OLIGOSPERMIA AND AZOOSPERMIA 477

Chromosomal analysis

This may be used to exclude Kleinfelter’s syndrome in patients presenting with azoospermia, small soft testes, gynecomastia, iFSH/LH, and dtestosterone.

Testicular biopsy

This is best performed as an open procedure. It is performed to assess if normal sperm maturation is occurring and for sperm retrieval (for later therapeutic use).

Diagnostic biopsy is indicated in azoospermic men with testes of normal size and consistency, palpable vasa deferentia, and normal FSH levels. Biospy may also be therapeutic, since sperm can be retrieved on testis biopsy from 25–50% of patients with Sertoli cell only syndrome, and 50–75% of men with maturation arrest. Multiple sample sites are performed if sperm are not immediately obtained.

Transrectal ultrasound

This is indicated for low semen volume to assess for ejaculatory duct obstruction. Men with ejaculatory duct obstruction will tend to have low semen volume and fructose, and semen pH <7.

Management

Treatment will depend on the underlying etiology.

•Transurethral resection of ejaculatory ducts (TURED) is associated with improved semen quality in 52%.

•Bilateral absence or agenesis of vas deferens: microsurgical epididymal sperm aspiration (MESA), or consider artificial insemination using donor (AID).

•Primary testicular failure with testicular atrophy: testicular sperm extraction (TESE); in vitro fertilization (IVF); or consider AID.

•Primary testicular failure with normal testis: TESE; IVF; AID

•Obstructive cause with normal testis: epididymovasostomy; vasovasostomy

478 CHAPTER 11 Infertility

Varicocele

Definition

Varicocele is dilatation of the veins of the pampiniform plexus of the spermatic cord.

Prevalence

This is the most common correctable cause of male infertility. Varicocele is found in 15% of men in the general population and 40% of males presenting with infertility. Bilateral or unilateral (left side affected in 90%).

Etiology

Incompetent values in the internal spermatic veins lead to retrograde blood flow, vessel dilatation, and tortuosity of the pampiniform plexus. The left internal spermatic vein enters the renal vein at a right angle, creating a column of blood that is under a higher pressure than that in the right vein, which enters the vena cava obliquely at a lower level. As a consequence, the left side is more likely to develop a varicocele.

Pathophysiology

Testicular venous drainage is via the pampiniform plexus, a meshwork of veins encircling the testicular arteries. This arrangement normally provides a countercurrent heat exchange mechanism that cools arterial blood as it reaches the testis. Varicoceles adversely affect this mechanism, resulting in elevated scrotal temperatures and consequent deleterious effects on spermatogenesis (± loss of testicular volume).

Varicocele grading system

Presentation

The majority of varicoceles are asymptomatic, although large varicoceles may cause pain or a heavy feeling in the scrotal area. Examine patient both lying and standing, and ask patient to perform Valsalva maneuver (strain down).

A varicocele is identified as a mass of dilated and tortuous veins above the testicle (described as feeling like a “bag of worms”), which decompress on lying supine. Examine for testicular atrophy, which is often associated with chronic testicular injury.

Investigation

•Scrotal Doppler ultrasound scan is diagnostic.

•Semen analysis: Varicoceles are associated with reduced sperm counts and motility, and abnormal morphology, either alone or in combination (oligoasthenoteratospermia).

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Management

Surgical ligation

•Retroperitoneal approach: A muscle-splitting incision is made near the anterior superior iliac spine, and the spermatic vessels are ligated at that level.

•Inguinal approach: The inguinal canal is incised to access the spermatic cord, and the veins are tied off as they exit the internal ring.

•Subinguinal approach: Veins are accessed and ligated via a small transverse incision below the external ring.

•Laparoscopic: Veins are occluded high in the retroperitoneum.

Surgical complications include varicocele recurrence, hydrocele formation, and testicular infarction and atrophy.

Surgical outcome

There is a 95% success rate; 70% of men have improvement of sperm parameters—most often motility, followed by count and then morphology. Testicular growth is often impaired in adolescents with varicoceles, but surgical repair may result in catch-up growth.

Embolization

In this interventional radiological technique, the femoral vein is used to access the spermatic vein for venography and embolization (with coils or other sclerosing agents).

480 CHAPTER 11 Infertility

Treatment options for male factor infertility

General treatment includes modification of lifestyle factors (reduce alcohol consumption; avoid hot baths).

Medical treatment

Correct any reversible causative factors.

Hormonal

•Antiestrogens (clomiphene citrate 25 mg qd) are often used empirically to increase LHRH, which stimulates endogenous gonadotrophin secretion.

•Secondary hypogonadism (pituitary intact) may respond to human chorionic gonadotrophin (hCG) 2000 IU subcutaneously 3 times a week, which stimulates an increase in testosterone and testicular size.

•Testosterone deficiency requires testosterone replacement therapy.

•Hyperprolactinemia is treated with dopamine agonists.

Erectile and ejaculatory dysfunction

Erectile dysfunction may be treated conventionally (oral, intraurethral, intracavernosal drugs; vacuum devices or prostheses). Ejaculatory failure may respond to sympathomimetic drugs (desipramine) or electroejaculation (used in spinal cord injury), where an electrical stimulus is delivered via a rectal probe to the postganglionic sympathetic nerves that innervate the prostate and seminal vesicles.

Antisperm antibodies

Corticosteroids have been used, but assisted conception methods are usually required.

Surgical treatment

Genital tract obstruction

•Epididymal obstruction can be overcome by microsurgical anastomosis between the epididymal tubule and vas (epididymovasovasostomy).

•Vas deferens obstruction is treated by microsurgical reanastomosis of ends of the vas, and is used for vasectomy reversal. Highest success rates for finding viable sperm occur in the first 8 years post-vasectomy (80–90%).

•Ejaculatory duct obstruction requires transurethral resection of the ducts.

Varicocele

This is repaired by embolization or open/laparoscopic surgical ligation.

Assisted reproductive techniques (ART)

Sperm extraction

This is used for obstructive azoospermia. Sperm are removed directly from the epididymis by microsurgical epididymal sperm aspiration (MESA) or by percutaneous retrieval (PESA). If these methods fail, testicular sperm extraction (TESE) or aspiration (TESA) may be tried.

TREATMENT OPTIONS FOR MALE FACTOR INFERTILITY 481

Sperm undergo cryopreservation until required. Later, they are separated from seminal fluid by dilution and centrifuge methods, with further selection of motile sperm and normal forms using Percoll gradiant techniques.

Assisted conception

•Intrauterine insemination (IUI): Following ovarian stimulation, sperm are placed directly into the uterus.

•In vitro fertilization (IVF): Controlled ovarian stimulation produces oocytes that are then retrieved under transvaginal ultrasound guidance. Oocytes and sperm are placed in a Petri dish for fertilization to occur. Embryos are transferred to the uterine cavity. Pregnancy rates are 20–30% per cycle.

•Gamete intrafallopian transfer (GIFT): Oocytes and sperm are mixed and deposited into the fallopian tubes via laparoscopy. Variations include zygote intrafallopian transfer (ZIFT) and tubal embryo transfer (TET).

•Intracytoplasmic sperm injection (ICSI): A single spermatozoon is injected directly into the oocyte cytoplasm (through the intact zona pellucida). Pregnancy rates are 15–22% per cycle.