抄録
The urinary incontinence in radical prostatectomy partly arises from the damage to the external urethral sphincter during the operation. The present study demonstrated that, as a means of preventing the damage to the sphincter, the prostate shape and the external urethral sphincter could be preoperatively identified using magnetic resonance (MR) imaging. Five necropsy specimens were examined. MR images were obtained in the sagittal plane, and the specimens were then cut and macroscopically examined. Two prostate shapes, croissant and doughnut, were easily identified by both methods. In the four croissant-shaped prostates, the external urethral sphincter was very well developed at the anterior surface of the prostate gland, and the membranous urethra was long. On the other hand, in the doughnut-shaped prostate it developed anteriorly and posteriorly, and the membranous urethra was short. Knowledge as to the prostate shape and the urethral sphincter acquired by MR imaging can help the surgeon to preserve the external urethral sphincter during prostatectomy
