Hannes Strasser

THE FEMALE URETHRAL SPHINCTER: A MORPHOLOGICAL AND TOPOGRAPHICAL STUDY

PURPOSE We reassess the anatomy and topography of the female urethral sphincter system and its innervation in regard to urethra sparing anterior exenteration and other surgical procedures. MATERIALS AND METHODS Anatomical and histological studies were performed on 9 fetal specimens and 4 adult cadavers. Using graphics software the anatomical structures of the true pelvis were reconstructed based on computerized tomography cross sections and digitized histological sections. On the adult cadavers anterior exenteration was performed to study the implications of the isolated urethra and its sphincter mechanism. RESULTS Strata of connective tissue were found to divide the smooth muscles of the proximal two-thirds of the female urethra into 3 layers. Computer guided 3-dimensional reconstruction of digitized histological sections showed that thin fibers of the pelvic plexus course to this part of the urethra. The majority of these fibers may be preserved by carefully dissecting the bladder neck and the proximal portion of the urethra, leaving the lateral vaginal walls intact. The striated rhabdosphincter, which is innervated by fibers of the pudendal nerve, was in the caudal third of the urethra. CONCLUSIONS A well-defined sphincteric structure or sphincter could not be anatomically recognized in the bladder neck region. The majority of rhabdosphincter fibers were found in the middle and caudal thirds of the urethra. Thus, in patients undergoing removal of the bladder neck and part of the proximal portion of the urethra continence can be maintained by the remaining urethral sphincter system, provided that innervation remains essentially intact.

AGE DEPENDENT APOPTOSIS AND LOSS OF RHABDOSPHINCTER CELLS

PURPOSE To our knowledge the exact age dependent morphological and functional changes of the sphincter mechanism have not been investigated. Therefore, cell densities of the urethra and the urethral rhabdosphincter across various age groups, and the appearance of apoptosis were examined to explore the changes in these structures during the aging process. MATERIALS AND METHODS Specimens were obtained from 16 male and 7 female cadavers 5 weeks to 92 years old. Histological sections were taken from 3 different levels of the rhabdosphincter and urethra. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling method was used to detect apoptosis in the urethra and rhabdosphincter. In all specimens relative volume densities of the striated muscle fibers, apoptotic indexes and diameters of the rhabdosphincter and urethra were determined. RESULTS An age dependent increase of apoptosis of the striated muscle fibers of the rhabdosphincter led to a dramatic decrease in the number of striated muscle cells. In the 5-week-old neonate 87.6% and in the 91-year-old woman 34.2% of the rhabdosphincter consisted of striated muscle cells. Overall, a direct linear correlation between the age of the specimens and decrease in volume densities of the striated muscle cells was evident. CONCLUSIONS The dramatic decrease in the number of striated muscle cells in the rhabdosphincter of the elderly due to apoptosis represents the morphological basis for the high incidence of stress incontinence in this population.

Anatomical radical retropubic prostatectomy: 'curtain dissection' of the neurovascular bundle.

To investigate the topographical relationship of the cavernosal nerves (CNs) to seminal vesicles, prostate, rhabdosphincter and urethra during the development of the prostate, and to use the resulting morphological data to modify the surgical technique of nerve‐sparing radical prostatectomy.

Anatomy and innervation of the rhabdosphincter of the male urethra.

The striated sphincter of the male urethra and its innervation are still a subject of controversy. Essentially, two concepts of its anatomy can be found in the literature. Some authors describe the rhabdosphincter as part of the urogenital diaphragm caudal to the prostate, others as a striated muscle which extends from the base of the bladder to the “urogenital diaphragm.”

Transurethral prostatectomy: Mortality and morbidity

In 1989 two large‐scale multicenter studies on the mortality and morbidity of transurethral resection of the prostate were published [Mebust et al.: J Urol 141:243–247, 1989; Roos et al.: N Engl J Med 320:1120–1124, 1989]. These studies caused us to perform a retrospective study on a total of 1,211 consecutive patients who underwent transurethral resection of the prostate at our department between January 1988 and July 1991.

Urinary incontinence in the elderly and age-dependent apoptosis of rhabdosphincter cells

With advancing age, a progressive and age-dependent decrease of the density of striated muscle cells can be observed in the rhabdosphincter. This continuous loss of striated muscle cells due to apoptosis may finally lead to urinary incontinence.

Anatomic and functional studies of the male and female urethral sphincter

Abstract A total of 28 human specimens (14 male, 14 female) was used to perform macro- and microscopic studies on the morphologic basis of the urethral continence mechanism. Furthermore, functional studies were performed in six sheep, with the aim of looking at the pudendal and autonomic innervation of the urethra and the rhabdosphincter, as well as the changes of autonomic innervation after selective denervation. Transurethral ultrasound was performed in 34 continent patients, in order to visualize the contractions of the rhabdosphincter. The membranous urethra is innervated by branches of the autonomic pelvic plexus. The rhabdosphincter is an omega-shaped loop of striated muscle fibers that is innervated by the pudendal nerves. These results are supported by the results of animal experiments that show that the autonomic nerves predominantly innervate and regulate the upper part of the urethra, whereas stimulation of the pudendal nerves leads to a contraction of the lower part of the sheep urethra. In electron-microscopy, marked degeneration of the smooth muscle cells could be seen in the sheep with bilateral denervation.

Autologous myoblasts and fibroblasts for female stress incontinence: a 1-year follow-up in 123 patients

To assess the efficacy and safety of the application of autologous myoblasts and fibroblasts for treating female stress urinary incontinence (SUI) after a follow‐up of ≥1 year.

Comparison of different prostate-specific antigen cutpoints for early detection of prostate cancer: Results of a large screening study

OBJECTIVES This study was designed to compare the usefulness of the normal prostate-specific antigen (PSA) level and the age-referenced PSA level in a large screening study for early detection of prostate cancer. METHODS A total of 21,078 subjects (aged 45 to 75 years) were participants in a 1-year prostate cancer screening project with PSA as the initial test. Of the volunteers, 1618 (8%) showed an elevated PSA level according to age-specific reference ranges, and using the normal PSA cutoff point (4.0 ng/mL), 1872 (9%) had elevated PSA levels between 4.0 and 6.5 ng/mL. RESULTS Biopsies in both groups were performed if the PSA level was elevated. We evaluated the effect on biopsy rate and cancer detection. A PSA cutoff point of 2.5 ng/mL in men 45 to 49 years old and a PSA cutoff point of 3.5 ng/mL in men 50 to 59 years old with normal digital rectal examination findings resulted in an 8% increase in the number of biopsies (66 of 778) and an 8% increase in organ-confined cancer detection. An increasing cutoff of 4.5 ng/mL in men 60 to 69 years old and 6.5 ng/mL in men 70 to 75 years old resulted in 21% fewer biopsies (205 of 983) and would have missed 4% of organ-confined tumors (8 of 220). CONCLUSIONS We conclude that the use of PSA age-specific reference ranges increases the detection of clinically important and organ-confined cancers in young men and decreases the number of biopsies in older men.

TRANSURETHRAL ULTRASOUND: EVALUATION OF ANATOMY AND FUNCTION OF THE RHABDOSPHINCTER OF THE MALE URETHRA

PURPOSE A combined anatomic-sonographic study was undertaken to investigate whether the anatomical arrangement and the contractions of the rhabdosphincter of the male urethra could be visualized by transurethral ultrasound. Furthermore, this new technique was compared with standard urodynamic tests. MATERIALS AND METHODS In 7 cadavers transurethral ultrasound was performed to define sono-morphological criteria of the rhabdosphincter, and the sonographic pictures were then compared to histological sections. In 48 patients the rhabdosphincter of the male urethra was investigated by transurethral ultrasound and urodynamic techniques. Of these patients 40 were completely continent after radical prostatectomy and 8 presented with urinary stress incontinence after transurethral resection of the prostate or radical prostatectomy. The decrease of the distance between the rhabdosphincter and the transducer during contraction served as quantitative parameter for the contractility of the muscle. RESULTS The anatomical arrangement and contractions of the rhabdosphincter loop could be clearly visualized on transurethral ultrasound (during contraction the rhabdosphincter retracts the urethra, pulling it towards the rectum). Ultrasound showed scars in 3 patients with postoperative urinary stress incontinence, thinning of the muscle in 3 complete atrophy of the rhabdosphincter in 2 and minimal contractions of the rhabdosphincter in 1. Urethral closure pressures were decreased and decrease in rhabdosphincter-transducer distance was statistically significantly decreased in the incontinent patients. CONCLUSIONS Our sono-morphological data and anatomical histological results strongly suggest that the rhabdosphincter constitutes the main component of the continence mechanism in post-prostatectomy patients. Unlike urethral pressure profiles, which can only reveal zones of higher intraluminal pressure between the bladder and the penile urethra, transurethral ultrasound is highly specific for measurement of the function of the rhabdosphincter.