Re: Basic anatomy and physiology of the prostate - some questions

"fgomsan@xxxxxxxxx" <fgomsan@xxxxxxxxx> wrote:

Dear Unk,

Is that the Russian version of "Uncle"? Just joking.

Thank you for taking the time to respond to my rather confused post. I
was just about to suggest to Pete that you probably wouldn't as I was
really asking for a condensed course in urology but then you came
through. I'll need a little time to absorb what you've written but
some questions that already come to mind are included in-line below.

At the end you suggest drawings. You might want to look at

http://www.prostate.com.ph/anatomy_prostate_diseases.htm

I'm not sure I buy this guy's theories but he has some interesting
drawings of the anatomy of the prostate including identification of
such items as the transitional zone (scroll down).

Too many complex and metaphysical questions for a relatively simple
subject. This urethral lining problem mesmerizes a lot of patients. I
will try to help.

1. prostatic urethral lining.
If you think of the prostatic urethra as the throat of a boy, and of
the prostatic hyperplasia as the tonsils in a boy's throat, you will
quickly understand that removing the hyperplastic tissue works exactly
as removing the tonsils. You have to cut through the epithelial lining
of the prostatic urethra to reach the hyperplastic tissue. When you
finish there is a wound in both cases, there is a surface that needs to
undergo repairs, and the borders of the wound start to grow new
epithelial cells that will eventually cover the wound surface. if you
look inside the boy's throat just after the operation you will see two
wound surfaces, if you look inside the prostatic urethra after TURP or
PVP, there is a 360º wound surface. After tonsillectomy, it is
impossible for those surfaces to stick together, because they are never
in contact. After TURP or PVP it is theoretically possible that two
surfaces in contact could develop adherences, but this is extremely
rare. TURP and PVP cavities usually have a diameter of 2-3 cm, so
surfaces do not stick together, and the urine gets between these
surfaces, making it difficult to develop adherences.

OK, I think I'm clear there although I wonder where the epithelial
cells come from to re-grow the urethra. (A problem similar to severe
skin burns.)

2. Prostatic ducts obstruction

Prostatic ducts can become obstructed, the glands keep secreting and
then you have a retention cyst. They are very common and easy to see
with ultrasound of the prostate. You can also see retention cysts after
TURP. So some of these ducts get obstructed with the surgery as you
sugggest, but this does not derive into major clinical problems.

Huh! See below.

A TURP could cut the ejaculatory ducts if it is very aggressive and
penetrates the so called central zone of the prostate, but usually TURP
and PVP are restricted to the hyperplastic tissue, that derives from
the transitional zone of the prostate. So it is relatively rare to
obstruct the ejaculatory ducts with prostatic surgery. It is not a
cause of much concern for patients or urologists. Some young people
suffer obstruction of the ejaculatory ducts after infections, or for
unknown causes and they notice they ejaculate less volume of semen, and
they have fertility problems, but this obstruction rarely causes pain
or other symptoms.

I'm not quite sure what a cyst is although I had one removed from my
elbow recently and my wife has them in her breasts. I suppose all that
one needs to know is that they're some type of non-cancerous growth
somewhere between a pimple and a skin tag. If I understand correctly
the ejaculatory ducts drain into the central zone and the destruction
of tissue is on the other side of the urethra in the transitional zone
(working on the drawings on the website I quoted above). I presume
this also means that hyperplastic tissue in the urethra cannot
obstruct the ejaculatory ducts?

Is the ultrasound of the prostate you mention in the paragraph about
prostatic ducts the TRUS procedure; i.e. relatively painless, quick
and simple?

Now we get to the nasty part. Personally if I suffer from bph at all
it's very minor but I do suffer from reduced (very much so) ejaculate
to the point where I now put out maybe a wet spot (aka prostate dust)
after much long effort. This is down from a tablespoon or more eight
to ten years ago (I'm in my mid-sixties). This is extremely
disconcerting to me and even repeated visits to my pcp with trials of
every possible medication that might help and to a urologist
specializing in sexual problems who informed me that "Medical science
can do nothing for you" I have not even the glimmer of a solution in
sight. Naturally your, "It is not a cause of much concern for patients
or urologists" and your flippant disregard of the obstruction of the
prostatic ducts is like a red flag to a bull (being Spanish you should
understand the figure of speech <g>). I regard sex as so important
that only a life-threatening situation would cause me to do anything
that would result in any interference with the process. And, despite
some PC comments by people who should know better, orgasm (the only
reason to have sex) is dependent upon duration of ejaculation and
duration is dependent upon quantity. Less quantity, shorter duration,
less pleasure.

I'm getting to the end of possible medical solutions although I have
yet to try L-Dopa (pcp doesn't think it would be appropriate),
Apomorphine (difficult to obtain in the US and extremely expensive),
and TRT (my T levels are mid-range as are all the other hormone
levels) so I had a thought that maybe I'm actually ejaculating more
but it's being forced back into the bladder due to weakness in the
bladder neck. The only (miniscule I agree) evidence for this is that
my urine is very frothy especially the first pee of the morning. OTOH
it's not more so immediately after sex. Still no one says that frothy
urine (cloudy, yes) is an indication of retrograde ejaculation. And
then it hit me (a "eureka" moment): If the prostatic urethra in bph
can become obstructed why not the ejaculatory ducts? Maybe I have huge
bloated seminal vesicles that have been trying to deliver their load
for years but their outlet has been closed off? Well it's worth some
investigation, hence my presence here and my question above about a
TRUS test.

There's an interesting site about ejaculatory duct blockage at

http://www.ejaculatoryductobstruction.org/

and a very informative paper by Paul Turek in pdf form at:

http://urology.ucsf.edu/patientGuides/pdf/maleInf/Treatment_Ejac_Duct.pdf

Unfortunately they too seem to think that the reason for sex is other
than pleasure.

3. prostatic urethra as a tube or duct:

I have not seen two prostatic urethras looking exactly the same. They
tend to be different, as prostatic shapes vary from person to person.
You never see two mouths that are exactly the same, do you?

Like snowflakes, nothing in nature is *exactly* the same but, although
I haven't made a study of it, I'd say all the mouths I've see have
been the same, commonly speaking. The landmarks--teeth, tongue, throat
opening, etc-- are the same.

Some
prostatic urethras look from the inside like an open tube, other
prostatic urethras are not an open tube, but an obstructed tube,
because there are two masses of tissue that grow from the sides and
coapt in the midline. Some urethras look like a tube with a full
bladder (there is pressure inside the prostatic urethral lumen and it
opens up) and as a colapsed tube when the bladder is empty.

Given that the external sphincter is the thing that stops urine
leaking out, isn't the prostatic urethra simply an extension of the
bladder and thus would be full of urine normally? Except immediately
after ejaculation (presuming good bladder neck control).

In the
embryo, the urethra is a tube that is only lined with epithelial cells.
Then some buds start to develop from the urethra and these buds invade
the surrounding mesenchyma (this is the name of embryonal tissue that
has not yet differenciated into a mature tissue). These buds are hollow
bags of epithelial cells that will later differenciate into the
prostatic glands (the parenchyma - the glandular tissue) - these cells
will secrete the prostatic secretion, and will produce the famous PSA.
The surrounding tissue will differenciate into the prostatic stroma
(collagen, smooth muscle fibers, elastin, and other components) - a
scaffold that will support the prostatic glands.

4. TURP and PVP and vaporization

TURP and PVP are performed with surgical instruments that allow for
continuous irrigation of the prostatic urethra and bladder. When tissue
is vaporized with a greenlight laser, or cut with a TURP resectoscope,
there are many tissue particles that float in this irrigation fluid and
are taken out of the patient through the scope. They just do not
condensate. TURP and PVP destroy the urethral lining (the correct word
should be endothelial - rather than epithelial, endo means inside, and
epi outside, so the epithelium applies to the skin, and the endothelium
to all "internal skins", it is used for any lining of internal organs),
but this epithelium grows again and when you look inside after some
time, you see it has regenerated completely. In some areas there is
some scar tissue, specially after TURP, but as it happens with wounds
in the skin, the regenerative process manages to cover the wound
surface completely.

5. Prostatic capsule.

The prostate does not have a proper capsule. It is surrounded by
fascial sheaths that are almost only visible under the microscope.

In a 20 year old prostate, there is an area near the bladder neck,
surrounding the urethral endothelium, the transitional zone, that will
be the origin of the benign hyperplastic tissue. It will start to grow
and it will progressively push the original prostatic tissue outwards.
In an old man with a big prostate, this growth of tissue from the area
surrounding the urethra will have pushed the original prostatic tissue
outwards, and between these two parts of the prostate, the central
hyperplastic tissue and the external original prostatic tissue there is
a very clear cleavage plane. When an open prostatectomy is performed,
the surgeon incises the prostate until he reaches this cleavage plane,
and then uses his finger to enucleate the hyperplastic tissue, he
breaks the urethra and extracts the BPH tissue with a hole in the
middle (like a donut) - the urethra. Then the incission is closed with
a suture. This gives the impression of a "surgical capsule", that is
tipically 5-10 mm thick, and this is really the original prostate.

This is an explanation of why Cornell think that the prostate can't
expand outwards. If I understand your paragraph correctly the original
prostate doesn't expand at all but it's pushed outwards by the new
tissue in the transitional zone. They're splitting hairs.

We surgeons talk about the capsule knowing that we refer to the
original prostatic tissue. When we perform TURP (well, I do not perform
TURP any longer) or PVP, we want to reach the "capsule" (the surgical
capsule), to make sure we remove all the hyperplastic tissue.
Apparently, some prostates are more distensible than others, and that
explains in part that some men with relatively small prostates are very
obstructed (the growth is not able to push the prostate outwards, so it
obstructs the urethral lumen) and some men with much bigger prostates
can urinate very well (a more distensible original prostate allows this
tissue to enlarge the prostate, and the urethra is not so compressed).
This also happens with e.g. kidney tumors. A tumor inside the kidney
can push the renal tissue and compress it and when you look at the
kidney it appears to be encapsulated, but what you see is renal tissue
that has been compressed and seems to form a capsule around the tumor.
Open prostatectomies on very big prostates are like opening the skin of
an orange (the surgical capsule or the original prostatic tissue) and
extracting the flesh (the hyperplastic tissue)...

6.- liposuction of the prostate...

Prostatic tissue is quite elastic, but it is also quite rubery or
tough... there is no way of performing what you suggest...The
hiperplastic tissue is a benign tumor of the prostate, it has stroma
(collagen, muscle fibres, etc..) and parenchyma (glandular tissue).
Ellen Shapiro from new york has been studying the proportion of stroma
and parenchyma in BPH, a difficult question to investigate.... but
there are two components also in BPH. The smooth muscle in the stroma
responds with relaxation to alpha blockers. The glandular tissue
responds to finasteride with atrophy. Both mechanisms derive in
symptoms improvement in patients through different mechanisms.

It is a pity these google groups do not allow for drawing. It would be
very nice to use some drawings to explain these things.

My best wishes to all, I hope this was helpful.

Very. Thanks once again.

Fernando Gómez Sancha
http://drgomezsancha2.blogspot.com

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