Waldemar Białek, Radosław Starownik, Krzysztof Bar
- Klinika Urologii i Onkologii Urologicznej AM w Lublinie
Introduction. Our interest in application of transrectal sonographic imaging for research on morphology and function of the urethral sphincteric system in men resulted from a compelling need for minimally invasive and a safe method able to reveal complex mechanisms responsible for continence.
Objectives. The aim of the study was determination of characteristic patterns of sphincteric mechanism in men from 3rd to 9th decade of life by means of transrectal ultrasonography.
Materials and methods. Urethral sphincteric system (USS) was visualized by means of transrectal ultrasound (Viking 2400, B&K Medical, Denmark; 8808 10 MHz probe). Examinations were performed in the left decubitus position at rest and during cough test in 250 men (20 in their 3rd, 25 in 4th, 40 in 5th, 50 in 6th, 50 in 7th, 40 in 8th and 25 in 9th decade of life. Every examination was recorded as video sequences and analyzed. In every case external urethral sphincter, bulbar part of penis, urethra and interpubic disc were identified and delineated in sagittal and transverse planes. Degree of urethral and bulbar compression due to bulbospongiosus muscle contraction at maximum cough was scaled, as well as mobility of urethra and contraction of USS.
Results. Contraction of USS and bulbospongiosus muscle during cough causes deviation downwards and retraction of bulbar urethra from pubic bones, more prominent at intense cough. Mobility of urethra gradually decreases with age. The most prominent compression of membranous and bulbar urethra has been observed within the youngest group. In men in their fifties and older morphology and function of USS grossly depended on prostatic enlargement (proximal part of external urethral sphincter atrophy in BPH). Larger prostates (more than 70 in volume) prevented prostatic migration during coughing, also distortion of the urethra was seen only within its short, membranous part. The best anatomical representation of even tiny muscular branches and fasciae were obtained in the youngest. Morphology of the urethral sphincteric system and adjacent structures were difficult to assess in men in their 8th and 9th decade of life, because of atrophic changes in muscles, post inflammatory fibrotic tissue or fat. In the oldest men sphincteric mechanism was significantly shorter and “hidden” in the pelvic floor. During straining and coughing Santorini’s venous plexus, irrespective of age plays a role of a natural buffer, thus enabling significant distortion of urethra in relation to symphysis pubis.
Conclusions. Transrectal ultrasound may be useful in assessment of morphology and, to some extend function of muscles surrounding urethra distally to the prostatic apex. It helps in understanding of complex mechanisms responsible for efficient continence at rest and during sudden rise in an intra-abdominal pressure.