Hans Colstrup

New probe for measurement of related values of cross-sectional area and pressure in a biological tube

A probe for measurement of related values of cross-sectional area (CA) and pressure in a biological tube has been developed to study passive and active closure forces in the female urethra. CA is measured in the range 0·13–1·00 cm2 by the field gradient technique. The system is able to produce an arbitrarily chosen CA in the urethra in about 50 ms. Pressure is measured in the range 0–150 cm H2O (0–14·7 kPa) by a microtransducer. The risetime of the pressure measuring system is 2·5 ms. Pressure needed for inflation and deflation of the balloon ranges from 2 to −5 cm H2O (0·2 to −0·5 kPa). The hysteresis of the balloon is approximately 1 cm H2O (0·1 kPa). The method permits estimation of urethral distensibility (rigidity/compliance), the real (noninstrumented) urethral closure pressure and urethral hysteresis. Furthermore, evaluation of the urethral closure function in terms of isometric contraction, isotonic contraction, muscular work and power can be performed.

A probe for measurements of related values of cross-sectional area and pressure in the resting female urethra

SummaryA probe for measurement of related values of cross sectional area (c.a.) and pressure in the resting female urethra has been developed. C.a. can be measured in the range 0.07 to 0.79 cm2 by means of the field gradient principle. Pressure is measured in the range 0 to 150 cm H2O. Pressure needed for inflation and deflation of the balloon ranges from +4 to-5 cm H2O with a hysteresis of 3 to 4 cm H2O. The probe is able to follow changes of the c.a. up to 0.7 cm2/sec. The method makes possible estimation of urethral stiffness/rigidity during distension of the balloon, estimation of the capability of contraction of the closure apparatus in terms of isometric and isotonic contraction, muscular work and power. Furthermore, hysteresis during inflation and deflation of the balloon can be described.

Mechanical properties of the urethra in healthy and stress incontinent females : dynamic measurements in the resting urethra

The relationship between pressure and cross-sectional area in the resting urethra during its inflation and deflation was examined in 30 healthy females and in 30 patients with genuine stress incontinence (GSI). Measurements were performed at the bladder neck, in the high-pressure zone and distally in the urethra. The mechanical properties of the urethra were found to vary significantly as a function of time after induction of a cross-sectional area (stress episode) in both groups of women. The pattern of response of the urethra showed significant differences between normals and GSI particularly during dynamic conditions. Our results indicate that mechanical laxity of the urethra at the bladder neck and midurethrally especially at dynamic events (stress episodes) is of pathophysiological importance in GSI.

Urethral Sphincter Electromyography with Vaginal Surface Electrodes: A Comparison with Sphincter Electromyography Recorded Via Periurethral Coaxial, Anal Sphincter Needle and Perianal Surface Electrodes

Urethral sphincter electromyography recording via vaginal surface electrodes was compared to simultaneous sphincter electromyographic registrations obtained with a periurethral coaxial needle electrode and perianal surface or needle electrodes in 10 neurologically intact women. Qualitative similarity of the vaginal surface and periurethral needle electrode recordings was found. Based on this and our previous studies, we conclude that electromyographic recording with vaginal surface electrodes offers a simple and reliable technique to evaluate the striated urethral sphincter during routine urodynamic studies in women.

A New Method for the Investigation of the Closure Function of the Resting Female Urethra

The field-gradient principle has been used in the development of a probe for the recording of related values of cross-sectional area and pressure in the resting female urethra. The probe is used in a manner that allows pressure to be increased in steps of 10 cm. water, distending the urethra up to a cross-sectional area of 0.79 cm.2. Recordings are performed at 0.5 cm. steps throughout the urethra. The obtained parameters make possible a description of the closure function in terms of urethral rigidity, closure pressure of the noninstrumented urethra, capability of isometric and isotonic contraction, muscular function and power of the closure mechanism.

Bladder Distension in the Management of Detrusor Instability

In a 10-year period, 15 patients were treated with bladder distension because of urinary symptoms associated with detrusor instability. All patients had failed to respond to previous drug therapy. Ten patients had previously undergone surgical procedures for urinary incontinence, also without success. Five patients had repeated bladder distensions performed because of lack of improvement after the first procedure. Follow-up cystometry was performed in 14 cases. In all cases the instability was unchanged. Only one patient reported improvement in voiding symptoms. No complications were seen. With a success-rate of 6% (1 out of 15 patients) we do not recommend bladder distension with the present procedure as therapy for detrusor instability.

VOIDING PROBLEMS IN PATIENTS WITH HIV INFECTION AND AIDS

The prevalence and type of urinary voiding problems were prospectively investigated in 77 men and four women (median age 36 years) with HIV infection or AIDS consecutively attending an outpatient clinic. Urologic symptoms were registered from replies to a questionnaire and urologic evaluation was made when indicated. All patients were neurologically examined. In addition, urodynamic data from ten consecutively referred HIV/AIDS patients were retrospectively analyzed. Two of the 81 prospectively studied patients had severe, and eight had moderate voiding problems, while 19 had pathologic findings at neurologic examination. Of three patients referred for urodynamic investigation, two were found to have neurogenic bladder dysfunction. In three of the total 13 urodynamically studied patients the findings suggested neurogenic bladder dysfunction secondary to the infection. We conclude that HIV/AIDS infection affects voiding only in minor degree, and when it does the disease is often advanced and dominated by symptoms from other organs. The relevance of urologic/urodynamic investigation in HIV/AIDS patients thus seems limited.

The Effect of α-Adrenoceptor Stimulation and Blockade on the Static Urethral Sphincter Function in Healthy Females

The influence of noradrenaline and prazosin on the urethral closure function was evaluated in 10 healthy female volunteers. Measurements of pressure at varying cross sectional areas were carried out at the bladder neck, in the high pressure zone, and in the distal urethra. Prazosin reduced the static pressure, predominantly in the midportion of the urethra, whereas noradrenaline caused no significant pressure change. The urethral resistance to dilatation and the hysteresis were unaffected by the two agents. It is suggested that the response to prazosin is related to decreased activity of the urethral smooth as well as of the striated muscles, the latter as a result of a reduced somatomotor output from the central nervous system.

The Influence of β-Adrenoceptor and Muscarinic Receptor Agonists and Antagonists on the Static Urethral Closure Function in Healthy Females

The effects of terbutaline, propranolol, carbachol, and atropine on the static urethral closure function were investigated in 20 healthy women. Terbutaline caused a statistically reduction of the urethral pressure in the high pressure zone, but not at the bladder neck or in the distal urethra. The other drugs caused no significant pressure changes. None of the drugs used produced significant changes in the static viscoelastic properties, elastance, and hysteresis of the resting urethra. It is suggested that terbutaline partly reduces intraurethral pressure by reducing muscular tone in the rhabdosphincter and pelvic floor.

Erectile Dysfunction following Direct Vision Internal Urethrotomy

A total of 104 evaluable patients 20-90 years old treated by direct vision internal urethrotomy a.m. Sachse for urethral strictures reported retrospectively via a questionnaire their sexual potency before and after internal urethrotomy. Eleven patients (10.6%) experienced partial or total erectile dysfunction following the operation, most of whom had distal and long strictures. Eight were evaluated for impotence and on grounds of a comprehensive history, physical examination, penile Doppler investigations, and papaverine tests it was concluded that 3 patients might have achieved an abnormal communication between the corpus cavernosum and corpus spongiosum. In two of the patients cavernosographies were carried out and in one total opacification of the corpus spongiosum was demonstrated, but the exact location of the leak could not be pinpointed, and surgical treatment therefore not rendered feasible. Possible factors in the development of erectile dysfunction following internal urethrotomy are analyzed.