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Ejaculatory duct obstruction | |
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Specialty | Urology ![]() |
Ejaculatory duct obstruction (EDO) is a pathological condition which is characterized by the obstruction of one or both ejaculatory ducts. Thus, the efflux of (most constituents of) semen is not possible. It can be congenital or acquired. It is a cause of male infertility and/or pelvic pain. Ejaculatory duct obstruction must not be confused with an obstruction of the vas deferens.
If both ejaculatory ducts are completely obstructed, affected men will demonstrate male infertility due to aspermia/azoospermia. They will suffer from a very low volume of semen which lacks the gel-like fluid of the seminal vesicles or from no semen at all while they are able to have the sensation of an orgasm during which they will have involuntary contractions of the pelvic musculature. This is contrary to some other forms of anejaculation.
In addition, it is reported to be a cause for pelvic pain, especially shortly after ejaculation. In case of proven fertility but unresolved pelvic pain, even one or both partially obstructed ejaculatory ducts may be the origin of pelvic pain and oligospermia. [1]
Ejaculatory duct obstruction may result in a complete lack of semen (aspermia) or a very low-volume semen (oligospermia) which may contain only the secretion of accessory prostate glands downstream to the orifice of the ejaculatory ducts.
In addition to the congenital form which is often caused by cysts of the Müllerian duct the obstruction can be acquired due to an inflammation caused by chlamydia, prostatitis, tuberculosis of the prostate and other pathogens. In addition, calculus was reported to mechanically block the ejaculatory duct, leading to infertility. [2] However, in many patients, there is no history of an inflammation and the underlying cause simply remains unknown.
Low-volume, runny/fluid semen (oligospermia) or no semen at all (dry ejaculation/aspermia) are a logical consequence of an obstruction downstream of the seminal vesicles which contribute most to the volume of the semen. Usually, men will be able to observe a runny/fluid, low-volume semen by themselves during masturbation. Since the seminal vesicles contain a viscous, alkaline fluid rich in fructose, a chemical analysis of the semen of affected men will result in a low concentration of fructose and a low pH. A microscopic semen analysis will reveal aspermia/azoospermia.
In contrast, if both vasa deferentia are obstructed (which may be the result of intended sterilization), a semen analysis will also reveal aspermia/azoospermia, but an almost normal volume of the semen, since the efflux of the seminal vesicles is not hindered. This is because approx. 80% of the volume of the semen is the gel-like fluid originating from the seminal vesicles whereas the fraction from the testicles / epididymis, which contains the spermatozoa accounts for only 5–10% of the volume of the semen. In addition, if an obstruction of the vasa deferentia is the cause for the azoospermia, the concentration of fructose in the semen will also be normal, since the fructose comes primarily from the fluid stored in the seminal vesicles. If the seminal-vesicles contain spermatozoa, but the semen does not, the obstruction must be downstream of the seminal vesicles and the ejaculatory ducts are very likely to be obstructed, provided that other causes for a dry ejaculation/aspermia such as a retrograde ejaculation are ruled out.
Attempts are sometimes made to diagnose an ejaculatory duct obstruction by means of medical imaging, e.g. transrectal ultrasound or MRI, [3] or by transrectal needle-aspiration of the seminal vesicles. However, transrectal ultrasound has a relatively low sensitivity of approx. 50% and thus is only a tool to rule-out cysts in the region of the orifices but is not sufficient to rule out an obstruction of the ejaculatory ducts due to other causes. In approx. 50% of cases of unexplained low-volume azoospermia MRI and TRUS do not reveal any pathological findings, because it is difficult to see alterations in a narrowed, scarred duct with these methods. Due to the blockage of ejaculatory ducts, enlarged seminal vesicles are frequently seen in patients with ejaculatory duct obstructions. However, this is again neither a proof of an obstruction nor do normal-sized seminal vesicles rule-out an obstruction of the ejaculatory ducts. [4]
A method to treat ejaculatory duct obstruction is transurethral resection of the ejaculatory ducts (TURED). [5] This operative procedure is relatively invasive, has some severe complications, and has led to natural pregnancies of their partners in approximately 20% of affected men. [6] A disadvantage is the destruction of the valves at the openings of the ejaculatory ducts into the urethra such that urine may flow backwards into the seminal vesicles. Another, experimental approach is the recanalization of the ejaculatory ducts by transrectal or transurethral inserted balloon catheter. [1] Though much less invasive and preserving the anatomy of the ejaculatory ducts, this procedure is probably not completely free of complications either and success rates are unknown. There is a clinical study currently ongoing to examine the success rate of recanalization of the ejaculatory ducts by means of balloon dilation. [7]
Usually, affected men have a normal production of spermatozoa in their testicles, so that after spermatozoa were harvested directly from the testes e.g. by TESE, or the seminal vesicles (by needle aspiration) they and their partners are potentially candidates for some treatment options of assisted reproduction e.g. in-vitro fertilisation. Note that in this case, most of the treatment (e.g. ovarian stimulation and transvaginal oocyte retrieval) is transferred to the female partner.
Ejaculatory duct obstruction is the underlying cause for 1–5% of male infertility. [8] Since ejaculatory duct obstruction is a relatively rare cause of infertility, this possibility may be unfamiliar to some physicians, even some urologists.
A spermatozoon is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote.
The prostate is both an accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found in all male mammals. It differs between species anatomically, chemically, and physiologically. Anatomically, the prostate is found below the bladder, with the urethra passing through it. It is described in gross anatomy as consisting of lobes and in microanatomy by zone. It is surrounded by an elastic, fibromuscular capsule and contains glandular tissue, as well as connective tissue.
Retrograde ejaculation occurs when semen which would be ejaculated via the urethra is redirected to the urinary bladder. Normally, the sphincter of the bladder contracts before ejaculation, sealing the bladder which besides inhibiting the release of urine also prevents a reflux of seminal fluids into the male bladder during ejaculation. The semen is forced to exit via the urethra, the path of least resistance. When the bladder sphincter does not function properly, retrograde ejaculation may occur. It can also be induced deliberately by a male as a primitive form of male birth control or as part of certain alternative medicine practices. The retrograde-ejaculated semen, which goes into the bladder, is excreted with the next urination.
The seminal vesicles are a pair of convoluted tubular glands that lie behind the urinary bladder of male mammals. They secrete fluid that partly composes the semen.
The epididymis is an elongated tubular structure attached to the posterior side of each one of the two male reproductive glands, the testicles. It is a single, narrow, tightly coiled tube in adult humans, 6 to 7 centimetres in length. It connects the testicle to the vas deferens in the male reproductive system. The epididymis serves as an interconnection between the multiple efferent ducts at the rear of a testicle (proximally), and the vas deferens (distally). Its primary function is the storage, maturation and transport of sperm cells.
The vas deferens, with the more modern name ductus deferens, is part of the male reproductive system of many vertebrates. The ducts transport sperm from the epididymis to the ejaculatory ducts in anticipation of ejaculation. The vas deferens is a partially coiled tube which exits the abdominal cavity through the inguinal canal.
The ejaculatory ducts are paired structures in male reproductive system. Each ejaculatory duct is formed by the union of the vas deferens with the duct of the seminal vesicle. They pass through the prostate, and open into the urethra above the seminal colliculus. During ejaculation, semen passes through the prostate gland, enters the urethra and exits the body via the urinary meatus.
The male reproductive system consists of a number of sex organs that play a role in the process of human reproduction. These organs are located on the outside of the body, and within the pelvis.
The human reproductive system includes the male reproductive system which functions to produce and deposit sperm; and the female reproductive system which functions to produce egg cells, and to protect and nourish the fetus until birth. Humans have a high level of sexual differentiation. In addition to differences in nearly every reproductive organ, there are numerous differences in typical secondary sex characteristics.
Azoospermia is the medical condition of a man whose semen contains no sperm. It is associated with male infertility, but many forms are amenable to medical treatment. In humans, azoospermia affects about 1% of the male population and may be seen in up to 20% of male infertility situations in Canada.
Terms oligospermia, oligozoospermia, and low sperm count refer to semen with a low concentration of sperm and is a common finding in male infertility. Often semen with a decreased sperm concentration may also show significant abnormalities in sperm morphology and motility. There has been interest in replacing the descriptive terms used in semen analysis with more quantitative information.
Aspermia is the complete lack of semen with ejaculation. It is associated with infertility.
Hypospermia is a condition in which a man has an unusually low ejaculate volume, less than 1.5 mL. It is the opposite of hyperspermia, which is a semen volume of more than 5.5 mL. It should not be confused with oligospermia, which means low sperm count. Normal ejaculate when a man is not drained from prior sex and is suitably aroused is around 1.5–6 mL, although this varies greatly with mood, physical condition, and sexual activity. Of this, around 1% by volume is sperm cells. The U.S.-based National Institutes of Health defines hypospermia as a semen volume lower than 2 mL on at least two semen analyses.
Male infertility refers to a sexually mature male's inability to impregnate a fertile female. In humans it accounts for 40–50% of infertility. It affects approximately 7% of all men. Male infertility is commonly due to deficiencies in the semen, and semen quality is used as a surrogate measure of male fecundity. More recently, advance sperm analyses that examine intracellular sperm components are being developed.
Anejaculation is the pathological inability to ejaculate despite an erection in males, with (orgasmic) or without (anorgasmic) orgasm.
A semen analysis, also called seminogram or spermiogram, evaluates certain characteristics of a male's semen and the sperm contained therein. It is done to help evaluate male fertility, whether for those seeking pregnancy or verifying the success of vasectomy. Depending on the measurement method, just a few characteristics may be evaluated or many characteristics may be evaluated. Collection techniques and precise measurement method may influence results.
Semen, also known as seminal fluid, is an organic bodily fluid created to contain spermatozoa. Spermatozoa are secreted by the gonads and other sexual organs of male or hermaphroditic animals and can fertilize the female ovum. Semen is produced and originates from the seminal vesicle, which is located in the pelvis. The process that results in the discharge of semen from the urethral orifice is called ejaculation. In humans, seminal fluid contains several components besides spermatozoa: proteolytic and other enzymes as well as fructose are elements of seminal fluid which promote the survival of spermatozoa and provide a medium through which they can move or "swim". The fluid is adapted to be discharged deep into the vagina, so the spermatozoa can pass into the uterus and form a zygote with an egg.
Ejaculation is the discharge of semen from the male reproductive tract as a result of an orgasm. It is the final stage and natural objective of male sexual stimulation, and an essential component of natural conception. Ejaculation can occur spontaneously during sleep, and is a normal part of human sexual development. In rare cases, ejaculation occurs because of prostatic disease. Anejaculation is the condition of being unable to ejaculate. Ejaculation is usually very pleasurable for men; dysejaculation is an ejaculation that is painful or uncomfortable. Retrograde ejaculation is the condition where semen travels backwards into the bladder rather than out of the urethra.
Dr. Paul J Turek is an American physician and surgeon, men's reproductive health specialist, and businessman. Turek is a recent recipient of a National Institutes of Health (NIH) grant for research designed to help infertile men become fathers using stem cells.
Male accessory glands (MAG) in humans are the seminal vesicles, prostate gland, and the bulbourethral glands . In insects, male accessory glands produce products that mix with the sperm to protect and preserve them, including seminal fluid proteins. Some insecticides can induce an increase in the protein content of the male accessory glands of certain types of insects. This has the unintended effect of increasing the number of offspring they produce.