The nature of the abnormality in bladder neck obstruction.

There is no dispute that there exists, in men, a condition of obstruction at the bladder neck in the absence of fibrous stricture or prostatic enlargement. The condition was clearly described by Guthrie (1836) and Young (1913) reported the results ff punch resection operation in over 50 cases. The large measure of success now achieved following resection of the bladder neck in these patients has perhaps been allowed to mask our ignorance of the nature of the abnormality and thus discourage studies of its cause. It is perhaps most often thought to result from fibrosis but a number of studies--for example Baadenoch (1949)--have shown no associated increase in fibrous tissue. Certainly the condition is in no way similar to the hard fibrous stricture seen more often in the distal urethra, or at the bladder neck as an occasional complication of prostatectomy. Our study shows that the obstruction if functional in nature and is due to the tightening of the bladder neck as the detrusor contracts.