Other causes of urinary obstruction[md]dyskinesia and bladder-neck fibrosis

There are two causes of urinary obstruction in which a patient's prostate feels normal rectally, with no sign that it is enlarged, but in spite of this his urine cannot pass. Between 5 and 10% of cases of prostatic obstruction are like this. He is usually younger than most patients with benign prostatic hypertrophy. You can pass a sound (or a cystoscope), and so exclude a stricture.

If you are able to examine such a patient through a cystoscope, you will find that his bladder is obviously obstructed, as shown by trabeculation, a hypertrophied interureteric bar, and perhaps diverticula. But you cannot see any sign of an enlarged prostate. Instead, the posterior lip of his urinary meatus is unduly prominent (difficult to see with an ordinary cystoscope).

These cases were formerly grouped together as the ''small fibrous prostate', a term which is no longer used. Instead, urologists now recognize: (1) Dyskinesia or bladder-neck dysfunction. This is a disorder of function, and cannot be diagnosed by feeling the internal meatus. (2) Bladder-neck stenosis, which is a true fibrosis of the bladder neck. One cause of this is a schistosomal fibrosis of the submucosa of the trigone.

You can treat bladder-neck dysfunction medically, with alpha blockers, or surgically, by cutting the fibres of the neck of the bladder.

BLADDER NECK DYSFUNCTION If you suspect the diagnosis before you operate, try phenoxybenzamine hydrochloride (''Dibenylene'), an alpha blocker, 10 mg daily or twice daily. This is symptomatic only, so treatment has to continue indefinitely. Orthostatic hypotension can be a problem.

If you set out to do a modified Freyer's operation, you may find, when you open the patient's bladder, that his prostate is not enlarged. Instead, he has a tight internal meatus, which you cannot put your finger into.

METHOD. Get adequate exposure[md]you cannot expose his internal urinary meatus through a short incision. Approach the inside of his bladder as for Freyer's prostatectomy (23.19).

Put a self-retaining retractor into his bladder, open it, and tilt the head of the table downwards slightly. Use a Langenbeck retractor, or a bent copper retractor, to draw the anterior wall of his bladder against his pubis, so that you can see his internal urinary meatus.

Identify the orifices of his ureters. Make deep cuts in his bladder neck in the 5 and 7 o'clock positions, sloping towards one another so as to excise a wedge of his bladder neck, as in J, Fig. 23-25. They must go deep enough to divide the circular fibres of the neck of his bladder. When you have cut them the neck of his bladder will spring open, and his obstruction will be relieved.

If Schistosoma haematobium [f41][s8][d9]is the cause, there will be more fibrosis, and you will be cutting fibrous tissue rather than muscle.

CAUTION ! (1) Take great care not to injure his ureters, as they enter his bladder. A wise precaution is to pass a 7 Ch catheter (or a feeding tube) into each of them. (2) If you find diverticula, leave them.

POSTOPERATIVELY, use any of the methods of irrigation or drainage in Section 23.19. Remove the urethral catheter on the 5th or 6th day. If his bladder was large and atonic at operation, insert a 16 or 18 Ch Foley catheter, and drain his bladder for 3 or 4 weeks into a bottle.