The Surgical Dissection Of The Male Bladder And Urethra Lateral And Bilateral Lithotomy Compared

Sources: Surgical Anatomy

Having examined the surgical relations of the bladder and adjacent

structures, in reference to the lateral operation of lithotomy, it

remains to reconsider these same parts as they are concerned in the

bilateral operation and in catheterism.



Fig. 1, Plate 54, represents the normal relations of the more important

parts concerned in lithotomy as performed at the perinaeal region. The

median line, AA, drawn rom the symphysis pubis above, to the point of

the coccyx below, is seen to traverse vertically the centres of the

urethra, the prostate, the base of the bladder, the anus, and the

rectum. These several parts are situated at different depths from the

perinaeal surface. The bulb of the urethra and the lower end of the

bowel are on the same plane comparatively superficial. The prostate lies

between these two parts, and on a plane deeper than they. The base of

the bladder is still more deeply situated than the prostate; and hence

it is that the end of the bowel is allowed to advance so near the

pendent bulb, that those parts are in a great measure concealed by

these. As the apex of the prostate lies an inch (more or less) deeper

than the bulb, so the direction of the membranous urethra, which

intervenes between the two, is according to the axis of the pelvic

outlet; the prostatic end of the membranous urethra being deeper than

the part near the bulb. The scalpel of the lithotomist, guided by the

staff in this part of the urethra, is made to enter the neck of the

bladder deeply in the same direction. On comparing the course of the

pudic arteries with the median line, A A, we find that they are removed

from it at a wider interval below than above; and also that where the

vessels first enter the perinaeal space, winding around the spines of

the ischia, they are much deeper in this situation (on a level with the

base of the bladder) than they are when arrived opposite the bulb of the

urethra. The transverse line B B, drawn in front of the anus from one

tuber ischii to the other, is seen to divide the perinaeum into the

anterior and posterior spaces, and to intersect at right angles the

median line A A. In the same way the line B B divides transversely both

pudic arteries, the front of the bowel, the base of the prostate, and

the sides of the neck of the bladder. Lateral lithotomy is performed in

reference to the line A A; the bilateral operation in regard to the line

B B. In order to avoid the bulb and rectum at the median line, and the

pudic artery at the outer side of the perinaeum, the lateral incisions

are made obliquely in the direction of the lines CD. In the bilateral

operation the incision necessary to avoid the bulb of the urethra in

front, the rectum behind, and the pudic arteries laterally, is required

to be made of a semicircular form, corresponding with the forepart of

the bowel; the cornua of the incision being directed behind. In the

lateral operation, the incision C through the integument, crosses at an

acute angle the deeper incision D, which divides the neck of the

bladder, the prostate, &c. The left lobe of the prostate is divided

obliquely in the lateral operation; both lobes transversely in the

bilateral.














Fig. 2, Plate 54.--If the artery of the bulb happen to arise from the

pudic opposite the tuber ischii, or if the inferior hemorrhoidal

arteries be larger than usual, these vessels crossing the lines of

incision in both operations will be divided. If the superficial lateral

incision C, Fig. 1, be made too deeply at its forepart, the artery of

the bulb, even when in its usual place, will be wounded; and if the deep

lateral incision D be carried too far outwards, the trunk of the pudic

artery will be severed. These accidents are incidental in the bilateral

operation also, in performing which it should be remembered that the

bulb is in some instances so large and pendulous, as to lie in contact

with the front of the rectum.










Fig. 1, Plate 55.--When the pudic artery crosses in contact with the

prostate, F, it must inevitably be divided in either mode of operation.

Judging from the shape of the prostate, I am of opinion that this part,

whether incised transversely in the line B B, or laterally in the line

D, will exhibit a wound in the neck of the bladder of equal dimensions.

When the calculus is large, it is recommended to divide the neck of the

bladder by an incision, combined of the transverse and the lateral. The

advantages gained by such a combination are, that while the surface of

the section made in the line D is increased by "notching" the right lobe

of the prostate in the direction of the line B, the sides of both

sections are thereby rendered more readily separable, so as to suit with

the rounded form of the calculus to be extracted. These remarks are

equally applicable as to the mode in which the superficial perinaeal

incision should be made under the like necessity. If the prostate be

wholly divided in either line of section, the pelvic fascia adhering to

the base of this body will be equally subject to danger. By incising the

prostate transversely, B B, the seminal ducts, G H, which enter the base

of this body, are likewise divided; but by the simple lateral incision D

being made through the forepart of the left lobe, F, these ducts will

escape injury. [Footnote] On the whole, therefore, the lateral operation

appears preferable to the bilateral one.



[Footnote: As to the mode in which the superficial and deep incisions in

lateral lithotomy should be made, a very eminent operating surgeon

remarks--"a free incision of the skin I consider a most important

feature in the operation; but beyond this the application of the knife

should, in my opinion, be extremely limited. In so far as I can

perceive, there should be no hesitation in cutting any part of the gland

which seems to offer resistance, with the exception, perhaps, of its

under surface, where the position of the seminal ducts, and other

circumstances, should deter the surgeon from using a cutting

instrument."--Wm. Fergusson, Practical Surgery, 3d Am. Ed., p. 610.]














Fig. 2, Plate 55.--The muscular structures surrounding the membranous

urethra and the neck of the bladder, and which are divided in lithotomy,

have been examined from time to time by anatomists with more than

ordinary painstaking, owing to the circumstance that they are found

occasionally to offer, by spasmodic contraction, an obstacle to the

passage of the catheter along the urethral canal. These muscles do not

appear to exist in all subjects alike. In some, they are altogether

wanting; in others, a few of them only appear; in others, they seem to

be not naturally separable from the larger muscles which are always

present. Hence it is that the opinions of anatomists respecting their

form, character, and even their actual existence, are so conflicting,

not only against each other, but against nature. In Fig. 2, Plate 55, I

have summed together all the facts recorded concerning them, [Footnote]

and on comparing these facts with what I have myself observed, the

muscles seem to me to assume originally the form and relative position

of the parts B C D E F viewed in their totality. Each of these parts of

muscular structure arises from the ischio-pubic ramus, and is inserted

at the median line A A. They appear to me, therefore, to be muscles of

the same category, which, if all were present, would assume the serial

order of B C D E F. When one or more of them are omitted from the

series, there occurs anatomical variety, which of course occasions

variety in opinion, fruitless though never ending. By that

interpretation of the parts which I here venture to offer, and to which

I am guided by considerations of a higher law of formation, I encompass

and bind together, as with a belt, all the dismembered parts of variety,

and of these I construct a uniform whole. Forms become, when not viewed

under comparison, as meaningless hieroglyphics, as the algebraic symbols

a + c - d = 11 are when the mind is devoid of the power of calculation.



[Footnote: The part C is that alone described by Santorini, who named it

"elevator urethrae," as passing beneath the urethra. The part B is that

first observed and described by Mr. Guthrie as passing above the

urethra. The part F represents the well-known "transversalis perinaei,"

between which and the part C there occasionally appears the part E,

supposed to be the "transversalis alter" of Albinus, and also the part

D, which is the "ischio bulbosus" of Cruveilhier. It is possible that I

may not have given one or other of these parts its proper name, but this

will not affect their anatomy.]














Fig. 3, Plate 55.--The membranous urethra A is also in some instances

embraced by two symmetrical fasciculi of muscular fibres B B, which

arising from the posterior and lower part of the symphysis pubis,

descend on either side of the canal and join beneath it. The muscles B

C, Fig. 2, Plate 55, are between the two layers of the deep perinaeal

fascia, while the muscle B B, Fig. 3, Plate 55, lies like the forepart

of the levator ani, C C, behind this structure and between it and the

anterior ligaments of the bladder. [Footnote] As to the interpretation

of the muscle, I, myself, am inclined to believe that it is simply a

part of the levator ani, and for these reasons--1st, it arises from the

pubic symphysis, and is inserted into the perinaeal median line with the

levator ani; 2nd, the fibres of both muscles overlie the forepart of the

prostate, and present the same arrangement in parallel order; 3rd, the

one is not naturally separable from the other.



[Footnote: This is the muscle, B B, which is described by Santorini as

the "levator prostatae;" by Winslow as "le prostatique superieur;" by

Wilson as the "pubo-urethrales;" by Muller as not existing; by Mr.

Guthrie as forming (when existing), with the parts B C, Fig. 2, Plate

55, his "compressor isthmi urethrae;" and by M. Cruveilhier as being

part of the levator ani muscle. "As in one case," (observes Mr. Quain,)

"I myself saw a few vertical muscular fibres connected with the

transverse compressor, it has been thought best to retain the muscle in

the text."--Dr. Quain's Anat., Am. Ed. vol. ii. p. 539.]












Fig. 1, Plate 56, represents by section the natural forms of the urethra

and bladder. The general direction of the urethra measured during its

relaxed state from the vesical orifice to the glans is usually described

as having the form of the letter S laid procumbent to the right side

[capital S rotated 90 degrees right] or to the left [capital S rotated

90 degrees left]. But as the anterior half of the canal is moveable, and

liable thereby to obliterate the general form, while the posterior half

is fixed, I shall direct attention to the latter half chiefly, since

upon its peculiar form and relative position depends most of the

difficulty in the performance of catheterism. The portion of the urethra

which intervenes between the neck of the bladder, K, and the point E,

where the penis is suspended from the front of the symphysis pubis by

the suspensory ligament, assumes very nearly the form of a semicircle,

whose anterior half looks towards the forepart, and whose posterior half

is turned to the back of the pubis. The pubic arch, A, spans crossways,

the middle of this part of the urethra, G, opposite the bulb H. The two

extremes, F K, of this curve, and the lower part of the symphysis pubis,

occupy in the adult the same antero-posterior level; and it follows,

therefore, that the distance to which the urethra near its bulb, H, is

removed from the pubic symphysis above must equal the depth of its own

curve, which measures about an inch perpendicularly. The urethral

aperture of the triangular ligament appears removed at this distance

below the pubic symphysis, and that portion of the canal which lies

behind the ligament, and ascends obliquely backwards and upwards to the

vesical orifice on a level with the symphysis pubis in the adult should

be remembered, as varying both in direction and length in individuals of

the extremes of age. In the young, this variation is owing to the usual

high position of the bladder in the pelvis, whilst in the old it may be

caused by an enlarged state of the prostate. The curve of the urethra

now described is permanent in all positions of the body, while that

portion of the canal anterior to the point F, which is free, relaxed,

and moveable, can by traction towards the umbilicus be made to continue

in the direction of the fixed curve F K, and this is the general form

which the urethra assumes when a bent catheter of ordinary shape is

passed along the canal into the bladder. The length of the urethra

varies at different ages and in different individuals, and its structure

in the relaxed state is so very dilatable that it is not possible to

estimate the width of its canal with fixed accuracy. As a general rule,

the urethra is much more dilatable, and capable consequently of

receiving an instrument of much larger bore in the aged than in the

adult.



The three portions into which the urethra is described as being

divisible, are the spongy, the membranous, and the prostatic. These

names indicate the difference in the structure of each part. The spongy

portion is the longest of the three, and extending from the glans to the

bulb may be said on a rough, but for practical purposes, a sufficiently

accurate estimate to comprise seven parts of the whole urethra, which

measures nine. The membranous and prostatic portions measure

respectively one part of the whole. These relative proportions of the

three parts are maintained in different individuals of the same age, and

in the same individual at different ages. The spongy part occupies the

inferior groove formed between the two united corpora cavernosa of the

penis, and is subcutaneous as far back as the scrotum under the pubes,

between which point and the bulb it becomes embraced by the accelerator

urinae muscle. The bulb and glans are expansions or enlargements of the

spongy texture, and do not affect the calibre of the canal. When the

spongy texture becomes injected with blood, the canal is rendered much

narrower than otherwise. The canal of the urethra is

uniform-cylindrical. The meatus is the narrowest part of it, and the

prostatic part is the widest. At the point of junction between the

membranous and spongy portions behind the bulb, the canal is described

as being naturally constricted. Behind the meatus exists a dilatation

(fossa navicularis), and opposite the bulb another (sinus of the bulb).

Muscular fibres are said to enter into the structure of the urethra, but

whether such be the case or not, it is at least very certain that they

never prove an obstacle to the passage of instruments, or form the

variety of stricture known as spasmodic. The urethra is lined by a

delicate mucous membrane presenting longitudinal folds, which become

obliterated by distention; and its entire surface is numerously studded

with the orifices of mucous cells (lacunae), one of which, larger than

the rest, appears on the upper side of the canal near the meatus. Some

of these lacunae are nearly an inch long, and all of them open in an

oblique direction forwards. Instruments having very narrow apices are

liable to enter these ducts and to make false passages. The ducts of

Cowper's glands open by very minute orifices on the sides of the spongy

urethra anterior to and near the bulb. On the floor of the prostatic

urethra appears the crest of the veru montanum, upon which the two

seminal ducts open by orifices directed forwards. On either side of the

veru montanum the floor of the prostate may be seen perforated by the

"excretory ducts" of this so-called gland. The part K, which is here

represented as projecting from the floor of the bladder, near its neck,

is named the "uvula vesicae," (Lieutaud.) It is the same as that which

is named the "third lobe of the prostate," (Home.) The part does not

appear as proper to the bladder in the healthy condition, Fig. 2, Plate

56. On either side of the point K may be seen the orifices, M M, of the

ureters, opening upon two ridges of fibrous substance directed towards

the uvula. These are the fibres which have been named by Sir Charles

Bell as "the muscles of the ureters;" but as they do not appear in the

bladder when in a state of health, I do not believe that nature ever

intended them to perform the function assigned to them by this

anatomist. And the same may be said of the fibres, which surrounding the

vesical orifice, are supposed to act as the "sphincter vesicae." The

form of that portion of the base of the bladder which is named "trigone

vesical" constitutes an equilateral triangle, and may be described by

two lines drawn from the vesical orifice to both openings of the

ureters, and another line reaching transversely between the latter.

Behind the trigone a depression called "bas fond" is formed in the base

of the bladder. Fig. 2, Plate 56, represents the prostate of a boy nine

years of age. Fig. 3, Plate 56, represents that of a man aged forty

years. A difference as to form and size, &c., is observable between

both.