Prostate shape, external striated urethral sphincter and radical prostatectomy: the apical dissection.

In an anatomical study of 64 gross specimens the external striated urethral sphincter was reconfirmed to extend as a single unit from the proximal penile urethra to the bladder base. The configuration of the external striated urethral sphincter was variable and was related to the shape of the apical prostate. Two basic prostatic shapes were recognized, distinguished by the presence or absence of an anterior apical notch. Whether a notch existed depended upon the degree of lateral lobe development and the position of its anterior commissure. In radical prostatectomy knowledge of the variation in the shape of the prostatic apex can help the surgeon to achieve optimal urethral transection with maximal preservation of the external striated urethral sphincter and other tissues of the continence mechanism.