Although commonly viewed as a single event, ejaculation is actually two separate processes, termed emission and ejaculation. During emission, the semen is “loaded” into the prostatic urethral chamber. After this, ejaculation is the forcible expulsion of semen from the penis in a series of spurts caused by rhythmic contractions, about 1 second apart, of the pelvic muscles. Ejaculation is different from orgasm or climax, the latter being an event that is centered in the brain that is closely associated with ejaculation.
Disordered ejaculation in which there is no semen produced at the time of
climax is called aspermia. This is different from azoospermia (see Plate 5-3),
in which semen is present but contains no sperm. In the absence of ejaculate,
there can be failure of ejaculation (anejaculation) or ejaculation into the bladder
(retrograde ejaculation). Failure of ejaculation can be a lifelong, primary
event (congenital anorgasmia) or an acquired problem (secondary anorgasmia).
The treatment of these conditions is different and important to distinguish.
Similar to a sneeze, ejaculation is a spinal reﬂex. With both, there is a
“point of no return” that occurs after the reﬂex is stimulated. Ejaculation is
under control of two nervous systems: the sympathetic (autonomic) nervous
system governs emission and the somatic nervous system controls ejaculation.
Sympathetic nerves arise from thoracolumbar spine at levels T10-L2. They form
the superior hypogastric plexus and run in front of the aorta in the back and
pelvis. Expulsion of the ejaculate is governed by the somatic nervous system
through the pudendal nerve (S2-S4). Interruption of either nervous system input
can result in ejaculatory disorders.
Premature ejaculation. The average time from vaginal penetration to
ejaculation in men is 9 minutes. Premature ejaculation is present when orgasm
occurs within 1 minute after vaginal penetration, or when ejaculation occurs
too early for female partner satisfaction. This problem occurs in 30% of adult
men, and it is the most common form of male sexual dysfunction. It can be due
to erectile dysfunction, anxiety, and nerve hypersensitivity and is treatable.
Importantly, although medications can “control” the problem and delay
ejaculation, “curing” the problem usually requires sex education to learn
control and satisfaction. Secondary premature ejaculation can be improved by
normalizing erection function in many cases.
Retrograde ejaculation. This is a straightforward diagnosis that requires
a history of aspermia, with a postejaculate urine sample showing sperm. Causes
include medical conditions such as diabetes mellitus, multiple sclerosis,
spinal cord injury, tethered spinal cord, spina biﬁda, medications such as
alpha-blockers, tricyclic antidepressants and ﬁnasteride, and surgical
procedures such as transurethral prostatic resection (TURP, see Plate 4-17),
V-Y plasty of the bladder neck, rectal, anterior spinal and retroperitoneal
procedures. The treatment of retrograde ejaculation depends on its cause. If
drug-induced, then the offending medication should be discontinued. Oral therapy with alpha-agonist agents can help
close the bladder neck and avoid entry of the semen into the bladder during
ejaculation. Sperm can also be “harvested” from the bladder and used for fertility procedures if needed.
Anejaculation. This condition can be congenital or acquired. Congenital
anorgasmia occurs in about 1/1000 men. Despite the lack of orgasm, nocturnal
emissions during sleep may occur. Treatment of primary anejaculation is
difﬁcult, as affected individuals often lack sensual awareness. Generally, treatment
is sought when the couple desires a pregnancy, as erections and sexual
performance are otherwise unaffected. Again, sex education has the highest
chance of curing this problem. Fertility issues can be bypassed with one or
more of the following techniques:
prostatic massage for sperm, collection and insemination of nocturnal semen
emissions, penile vibratory stimulation or rectal probe electroejaculation, or
sperm retrieval (see Plate 5-7). Secondary or acquired anejaculation can be due
to the same medications that cause retrograde ejaculation. Anejaculation can
also be caused by diabetes, multiple sclerosis, and spinal cord injury. In
these cases, penile vibratory stimulation, rectal probe ejaculation, or
surgical sperm retrieval techniques can be used to achieve fertility.