THE

or URGT..,OGY

Copyright© 1976

The \li/iJlia;-_ns

V!ilkins Co.

THE PATHOLOGY OF URETHRAL STRICTURE MANMEET SINGH

AND

J.P. BLANDY

From the Department of Urology, The London Hospital, Whitechapel, London, England

ABSTRACT

In this 3-part study the distribution of the post-gonococcal stricture has been related to the disposition of mucous glands in paraurethral glands by mapping the distribution of these glands in the human male urethra. Experimental study in the rat has indicated the role of extravasation of urine in the pathogenesis of urethral stricture. Lastly, the ultrastructure of urethral stricture tissue has revealed features that suggest why some strictures are fibrous and others resilient. The development of urethroplasty techniques during the last 20 years should not blind us to the fact that we know little about the etiology or pathogenesis of urethral stricture. Our experience has been with 216 urethroplasties and as many more cases of stricture that were managed by traditional bougienage. This technique has made us ponder again 3 questions that have troubled urologists since operations began. 1 1) Why does gonorrhea affect only certain parts of the urethra? 2) Does extravasation of urine play a significant role

past the suture line of a newly constructed urethroplasty. However, there was no clear evidence of the part played by this extravasation in the etiology of stricture. Several authors regarded extravasation of little importance• and Turner-Warwick advised the use of a fenestrated catheter in the management of urethral operations. 7 Classical descriptions of the histopathology of a stricture were those of fibrous replacement of the corpus spongiosum. No mention was made of any feature in this scar tissue that could make one stricture the quality of rubber and the other of fibrous tissue. To examine this possibility was our second task.

lllAGIUHTIJJI.LU~TtiTfllo !l!.STllrnuTmN (.)I" PAIUURETHRAL GW.)l!JS

I

\

\

....

\

'

b

"



\

-

~- ' ~

DISTRIBUTION OF PARAURETHRAL GLANDS

' -r· ~

FIG. l. Disposition of paraurethrai giands traced with microscope drawing tube.

FIG. 2. Sites of post-gonococcal urethral stricture and map of distribution of paraurethral glands.

in making strictures worse? 3) Why are some strictures fibrous and othern resilient? 2 Hirsch had noted that the urethra of most mammals, with the exception of man and the guinea pig, was devoid of paraurethral mucous glands. 3 More recent work also has emphasized the way the gonococcus singles out and colonizes the mucous cell.' It is not known where the mucous glands are situated in man since no precise anatomical description of them is available. 5 It seemed obvious to ask whether the distribution of the glands might explain the incidence of stricture but this was a task that had to be tackled since no such anatomical map was available. It was well known that extravasation of urine could make havoc of the perineum and our attention often had been drawn to the peculiar pain patients experienced when urine leaked Accepted for publication September 19, 1975. Read at annual meeting of American Urological Association, Miami Beach, Florida, May 11-15, 1975. 673

DISTRIBUTION OF MUCOUS GLANDS !N THE URETHRA OF MAN

Methods. Two infant and 2 adult male urethras were examined by serial section at 10 mµ. stained with hematoxylin and eosin. The position of the paraurethral glands was traced with a microscope and drawing tube (fig. 1). From these serial drawings the distribution of the glands was mapped (fig. 2). Results. No glands were discovered in the membranous urethra but the proximal bulbar urethra had a rich distribution of glands that extended deeply into the corpus spongiosum and were distributed circumferentially around the urethra (fig. 3). At the penoscrotal junction these glands became sparse and smaller in size. In the penile urethra glands were almost absent except for the short segment behind the meatus, where there was a small collection of mucous glands. This arrangement of the mucous glands of the urethra exactly matched the distribution of the sites where stricture is encountered after gonorrhea (fig. 2).

674

SINGH AND BLANDY

Fm. 3. Low power photomicrograph shows urethral lumen and disposition of paraurethral glands in bulbar urethra. Tunica albuginea is seen at periphery.

A

VESICOSTOMY

CRUSH 15SKs

CRUSH• BACTERIA

V WINDOW

~

COMPLETE

TRANSECTION

DAYS 3

LESION

AFTER

14

cystostomy

cystostomy

ACID

Q

[0

21

0

0

[J

died

Q

0

0

D

0

0

CRUSH

CRUSH & BACTERIA

INJURY

0

0 cystostomy

Fm. 4. A, 5 lesions produced in rat urethra. B, approach to rat's urethra; arrow points to site in urethra used in all experiments.

WINDOW

• •• • +111 .,JI .,1"

0 a TRANSECTIONt-------t-----------ystostomy

ROLE OF EXTRAVASATION OF URINE

D

Methods. Lesions of different types were produced in the urethra of the rat (fig. 4, A), which was exposed through a lower (]Reaction II Severe reaction abdominal incision (fig. 4, B). Rats were sacrificed at serial • Stricture intervals from 3 to 21 days after injury, and the urethra was fixed, removed and serial sectioned to study the sequence of Fm. 6. Summary of results of experiments in rat to illustrate effect of events. Sections were stained with hematoxylin and eosin and extravasated urine on healing in urethra.

PA'THOLOGY O~S" URETHRAL STBJCTURE

trichron1e stain. V~lhen there vvas an vvith from the serial sections that a stricture had been formed a 3-dimensional model was constructed. In a control series of rats the same injury was inflicted but the urine was diverted by a modified Lapides-type cystostomy (fig. 5). Results. The results are summarized in figure 6. It will be noted that crushing the urethra did not cause a stricture, and even the more severe forms of injury were not always followed

much r,2action except in those cases in which the urine was not diverted (fig. 7). It is to escape the conclusion that urinary extravasation exacerbated the inflammatory process that could, in some cases, lead to complete stenosis of the urethra. NATURE OF HUMAN URETHRAL STRICTURES

Methods. Biopsies of the diseased urethra removed at 24 urethroplasty operations for stricture of varying etiology were cut into millimeter cubes, fixed and embedded in epoxy resin. Sections were cut at 1 mµ. and stained with toluidine blue. Others were sectioned at 700 angstrom units and examined electron microscopy. Results. To our surprise it was found that in addition to fibroblasts and the predicted scar tissue there was in the majority of these strictures a varying but striking element of smooth muscle, together with a considerable quantity of elastic fibers (fig. 8). DISCUSSION

These studies have provided a partial answer to our 3 classical questions. The explanation for the well known sites of strictures after gonorrhea is explained by the anatomical distribution of mucous glands in the paraurethral tissues of man, a fact which seems to have escaped the attention of previous students of the human male urethra. The second question concerning the role of extravasation of urine in the etiology of stricture has been answered only partially and for the urethra of the rat but in this animal model there is no doubt that post-traumatic inflammatory reaction is much more severe and may proceed to total stenosis when extravasation has not been prevented by means of a suprapubic vesical diversion. Finally, the age old urologist's concept of the yielding, rubb~ry or spasmodic stricture finds some anatomical support in the discovery of smooth muscle and elastic fibers among the scar tissue of the typical urethral stricture. CONCLUSIONS

Fm. 7. A, section of rat urethra 4 days after crush injury when urine had been diverted shows practically no periurethral fibrocytic reaction. B, corresponding experiment with extravasation of urine shows marked periurethral fibrocytic reaction.

Our results lead to the conclusion that there is a simple anatomical explanation for the way in which the urethra is affected by gonorrhea, that extravasation should be avoided in the management of injury to the urethra and that elements exist in the scar that composes stricture, which could be responsible for an element of spasm.

FIG. 8. Post-inflammatory urethral stricture (1 mµ. section) stained with toluidine blue shows smooth muscle cell and collagen. Elastic tissue is represented by darkly stained fibers.

676

SINGH AND BLANDY REFERENCES

1. Attwater, H. L.: The history of urethral stricture. Brit. J. Urol., 15:

39, 1943. 2. Hunter, J.: A Treatise on Venereal Diseases, 2nd ed. London: Leicester-Square, 1786. 3. Hirsch, E.W.: Comparative histology of the urethral mucosa and its relationship to gonococcal infections. J. Urol., 17: 575, 1927. 4. Ward, M. E. and Watt, P. J.: Adherence ofNeisseria gonorrhoeae to urethral mucosa cells: an electron-microscopic study of human

gonorrhea. J. Infect. Dis., 126: 601, 1972. 5. Stieve, H.: Mannliche Genitalorgane. In: Handbuch der Mikroskopichen Anatomie des Menschen. Edited by W. von Mollendorff. Berlin: Julius Springer, band VII, Tl.2, 1930. 6. Mitchell, J. P.: Problems in diagnosis of bladder and urethral injuries. Proc. Roy. Soc. Med., 66: 631, 1973. 7. Turner-Warwick, R.: Observations on the treatment of traumatic urethral injuries and the value of the fenestrated urethral catheter. Brit. J. Surg., 60: 775, 1973.

The pathology of urethral stricture.

THE or URGT..,OGY Copyright© 1976 The \li/iJlia;-_ns V!ilkins Co. THE PATHOLOGY OF URETHRAL STRICTURE MANMEET SINGH AND J.P. BLANDY From the D...
275KB Sizes 0 Downloads 0 Views