A surgeons explanation of PVP and TURP on the urethra and the prostate

This was posted on a News Group in 2006 by a Spanish urologist Dr Sancha. It is one of thousands that I kept.

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.

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.

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.

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? 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. 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.

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.

Fernando Gómez Sancha

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