The influence of prostatic anatomy on the differing results of prostatectomy according to the surgical approach.

An anatomical study of cadaver prostates has demonstrated that, in all cases, adenomatous tissue lies inferior to the verumontanum. The proportion of tissue distal to the verumontanum varies from less than 10 to 50%. In a series of 100 patients the post-operative urodynamic studies showed that in the tansurethral resection group the mean urethral length was longer, the flow rate lower and the residual urine higher than in the retropubic prostatectomy group. It is suggested that prostatectomy by the transurethral route is less complete due to residual sub-verumontanal prostatic tissue. However, it is likely that by restricting resection to supra-verumontanal tissue many patients are spared post-operative stress incontinence.