Biomedical subjects

Stephan Bross

Publications and source records attributed to Stephan Bross.

9 recordsLinked to original sources

PubMed2007

Correlation between motor function and lower urinary tract dysfunction in patients with infantile cerebral palsy.

AIMS: The aim of this study was to evaluate urodynamic findings in patients with infantile cerebral palsy (CP) and to correlate the findings with impaired motor function. METHODS: We conducted a videourodynamic investigation on a highly select group of 29 patients (3-53 years). Motor function was assessed in each patient by the Gross Motor Function Classification System for CP (GMFCS). With this system, motor function is divided into five levels: patients in Level I have the most independent motor function and patients in Level V the least. The patients were divided into Group 1 (23 symptomatic patients with recurrent urinary tract infection or urinary incontinence) and Group 2 (6 asymptomatic patients). RESULTS: In Group 1, 21 patients (91%) had reduced compliance (0.6-16.4 ml/cmH(2)O) and 16 patients (70%) had increased DLPP (>40 cmH(2)O). Detrusor overactivity and pelvic floor overactivity were found in all 23 patients. In Group 2, two patients (33%) had reduced compliance (0.7 and 5.8 ml/cmH(2)O) and four (67%) had increased DLPP (>40 cm H(2)O). Detrusor overactivity and pelvic floor overactivity were observed in five patients (83%). Symptomatic patients showed higher GMFCS levels than asymptomatic patients. In the group of asymptomatic patients, there was no one classified as Levels IV or V, while there were no symptomatic patients classified as Level I. CONCLUSIONS: We conclude that urinary symptoms and pathological urodynamic findings increase along with the degree of motor function impairment shown by the GMFCS. Pathologic urodynamic findings can be found in both symptomatic and in asymptomatic patients.

Adolescent↗

PubMed2006

Inhibitory effects of L- and T-type calcium antagonists on contractions of human detrusor muscle.

The inhibitory and relaxant effects of the L-type calcium antagonists nifedipine, nimodipine, verapamil and diltiazem, and of the T-type calcium antagonist mibefradil, on contractions of isolated human detrusor muscle were investigated. The tissue was obtained from 10 patients undergoing cystectomy due to bladder cancer. Effects of the calcium antagonists at different concentrations on the concentration-response curves for carbachol were investigated. Furthermore, concentration-relaxation curves were performed using potassium-precontracted muscle strips. All L-type calcium antagonists suppressed the mean concentration-response curve of carbachol significantly at a concentration of 10(-6) M. Mibefradil up to 10(-5) M did not significantly suppress it. Nifedipine significantly reduced the carbachol-induced maximum contraction to 75% and 44%, verapamil to 75% and 67% of the appropriate control value at concentrations of 10(-7) and 10(-6) M, respectively. Diltiazem reduced it insignificantly to 96% and 71% at the above-mentioned concentrations. The concentration-relaxation experiments revealed following pD2-values and maximum relaxations of nifedipine, nimodipine, verapamil and diltiazem, respectively: 6.23, 6.37, 5.66, 5.81 and 85%, 83%, 82%, 90%. Maximum relaxations and pD2-values were not significantly different from each other. The lowest concentration, for which a significant effect compared to control in Student;s t-test was found, amounted to 10(-10) M, 10(-9) M, 10(-7) M, 10(-6.5) M and 10(-4) M for nimodipine, nifedipine, diltiazem, verapamil and mibefradil, respectively. L-type calcium antagonists are very potent relaxant agents of the human detrusor muscle in vitro.

Adult↗

PubMed2006

Inhibitory effects of various L-type and T-type calcium antagonists on electrically generated, potassium-induced and carbachol-induced contractions of porcine detrusor muscle.

The inhibitory effects of different calcium antagonists on contractions of isolated porcine detrusor muscle were investigated. Suppression of the maximum potassium-induced contraction and electrically generated contractions by nifedipine, verapamil and diltiazem were investigated. Furthermore, concentration-response curves of carbachol after pretreatment with the L-type antagonists nifedipine, verapamil, diltiazem, nimodipine and the T-type antagonist mibefradil at different concentrations were performed. Nifedipine significantly reduced the potassium-induced maximum contraction to 89, 60, 21, 8 and 4% (10(-9)-10(-5) M). Verapamil and diltiazem significantly reduced it to 64, 30 and 5% (10(-7)-10(-5) M) or 79, 27, 7 and 1% (10(-7)-10(-4) M), respectively. Nifedipine, verapamil and diltiazem significantly reduced the electrically generated contraction to 55, 36, 34 and 25% (10(-7)-10(-4) M), 71, 32 and 2% (10(-6)-10(-4) M), 96, 78, 38 and 5% (10(-7)-10(-4) M), respectively. pD2 values of nifedipine, verapamil and diltiazem amounted to 7.07, 5.56 and 5.40 and differed significantly. After pretreatment with nifedipine at 10(-6) M, the concentration-response curve of carbachol was nearly suppressed. The effects of nimodipine, verapamil and diltiazem were smaller. Mibefradil caused only at 10(-5) M a significant reduction. All investigated L-type calcium antagonists were strong inhibitors of the examined contractions. Nifedipine showed the biggest inhibitory effect.

Animals↗

PubMed2005

[Botulinum toxin injection for neurogenic and no neurogenic bladder dysfunction].

OBJECTIVES: Botulinum toxin A (BT A) has gained popularity among urologists in the treatment of detrusor muscle dysfunctions. The aim of this article is to review our experience with this therapy METHODS: From 2001 we used BT A in 28 patients. It was injected in the bladder wall under cystoscopical vision. We analyze the indication of treatment, clinical data and urodynamics before and after treatment. RESULTS: We treated 28 patients. 71 percent had neurogenic hyperreflexic bladder, 18% idiopathic unstable bladder and 11% other diseases. No direct complications were observed. Neurogenic hyperreflexic bladder (n = 20): Mean preoperative bladder capacity was 220 cc, improving to 430 cc after treatment. Non inhibited contractions disappeared. All patients except one with multiple sclerosis, who had spontaneous voiding, required self catheterization after injection. Average time interval between injections was 8.6 months. Idiopathic unstable bladder (n = 5): a lower dose was used, with an average of 100 U. Non inhibited contractions disappeared and all patients were able to maintain spontaneous voiding with post void residuals under 50 ml. No patients required self catheterization. Bladder capacity improved from 128 ml to 370 ml. Average number of voidings per day diminished from 16 to 7 times. Other diseases (n = 3): results were poor in these patients. There were no changes in either bladder function studies or average voiding frequency (15 times per day). These patients required surgery for bladder augmentation in 2 cases and continent diversion in 1 case. CONCLUSIONS: BT A has a role in the treatment of neurogenic hyperreflexic bladder diminishing incontinence and improving bladder capacity. In cases of idiopathic unstable bladder without anatomical changes its results are promising, but a limited number of patients does not allow a definitive conclusion. In other bladder diseases with anatomical changes results are poor and its use should not be routinely recommended.

Adult↗

PubMed2003

The role of the carbachol test and concomitant diseases in patients with nonobstructive urinary retention undergoing sacral neuromodulation.

The aim of this study was to evaluate the percutaneous nerve evaluation (PNE) test success in patients with nonobstructive urinary retention. A total of 24 PNE tests were performed in patients with nonobstructive urinary retention and in 18 patients, a carbachol test was performed during urodynamics. The diagnosis relating to the acontractile detrusor was also assessed and compared to the outcome of the PNE test. The PNE test was successful in eight of 24 patients (33.3%) with the the highest success rate being observed in patients after hysterectomy (80%). It was successful in five of 12 patients with negative carbachol tests and in three of six patients with positive carbachol tests. We conclude that sacral neuromodulation is an effective treatment option in patients with nonobstructive urinary retention. PNE tests should be performed in all patients with therapy resistant nonobstructive urinary retention, because predictive factors do not exist.

Adult↗

PubMed2003

Preoperatively evaluated bladder wall tension as a prognostic parameter for postoperative success after surgery for bladder outlet obstruction.

OBJECTIVES: To evaluate a novel method for the determination of bladder wall tension (BWT) and to correlate these findings with postoperative persistent residual urine, postoperative uroflow, International Prostate Symptom Score, and quality-of-life index in patients with bladder outlet obstruction. METHODS: In 28 male patients with prostate enlargement or bladder neck sclerosis undergoing surgical treatment, the preoperative BWT was determined after urodynamic investigation and ultrasound determination of bladder weight. The patients were divided into two groups: group 1 (n = 24), postoperative residual urine volume less than 50 mL; and group 2 (n = 4), persistent residual urine volume greater than 50 mL. Five patients in group 1 were unobstructed in accordance with the Abrams-Griffiths nomogram. This group was compared separately with group 2, in which all 4 patients were also classified as unobstructed. RESULTS: The preoperative BWT in group 1 was 5.2 +/- 4.1 N/cm(2), significantly different from the preoperative BWT in group 2 (0.98 +/- 0.3 N/cm(2)). The BWT in the 5 unobstructed patients in group 1 (3.4 +/- 1.3 N/cm(2)) was significantly greater than that in patients in group 2. BWT was the sole parameter that was distinctly different between these 5 patients and the patients in group 2, with a significant influence on postoperative uroflow, International Prostate Symptom Score, and quality-of-life index. CONCLUSIONS: The results of this pilot study show that the determination of BWT allows further evaluation of the detrusor function. Especially in patients classified as unobstructed according to the Abrams-Griffiths nomogram, preoperative determination of the BWT could become a supplemental and important parameter with predictive value for postoperative success in patients with prostate enlargement or bladder neck sclerosis.

Aged↗

PubMed2002

Cerebral electrical response on urinary bladder filling: first experimental findings.

Micturition disorders in neurologic diseases are often combined with reduced bladder sensation. Bladder sensation is important to time the void appropriately and to prevent bladder overdistension. We attempted to evaluate cerebral evoked potentials by bladder distension to objectively determine bladder sensation. In six rabbits, cerebral evoked potentials were evaluated by averaging cerebral responses to bladder distension. We stimulated the bladder with a computerized air pump system, resulting in repeated filling and emptying of the bladder. The number of stimulations, stimulation intensity, and different electroencephalograph electrode positions (both mastoids and frontal) were investigated. In all rabbits, cerebral evoked potentials were observed after 500 stimulations when stimulation pressure exceeded a certain threshold. Optimum response was observed after 1,000 stimulations. The latency of response of the frontal electrode position was observed after the mastoidal response with a significant delay of approximately 0.8 seconds. The latencies were significantly different when using different stimulation intensities. At lower intensity (mean pressure, 16.6 mm Hg), the response was observed after 4.531 +/- 0.909 seconds. At higher intensity (mean pressure, 19.0 mm Hg), cerebral response was observed after a latency of 3.971 +/- 0.735 seconds. We conclude that recording of cerebral evoked potentials by bladder distension is possible, resulting in an objective evaluation of afferent pathways from the bladder. In combination with subjective perception of bladder fullness, this finding may be a conceivable basis for a biofeedback training program to recover bladder sensation in patients with reduced bladder sensation.

Afferent Pathways↗

PubMed2002

Evaluation of superficial papillary ablation by endoscopic lasers in an ex vivo kidney model.

BACKGROUND AND PURPOSE: Endoscopic examinations of stone-forming kidneys show a coincidence of plaques and microliths on the surface of and within papillary epithelial tissue. These calcifications are thought to be precursors of calcium oxalate urolithiasis. We hypothesized that minimally invasive endoscopic laser ablation of microliths and necrotic cell layers enables epithelial regeneration and prevents recurrent urolithiasis. The aim of this study was to determine the most suitable laser type and dose intensity for selective superficial cell ablation. MATERIALS AND METHODS: Conventional Nd:YAG (1-40 W) or Ho:YAG (0.5-3 J/single impulse) lasers were used endoscopically on an ex vivo blood-perfused porcine kidney model. Defined doses were applied to the papillary surface in the contact and noncontact modes for 10 to 30 seconds. Papillae were excised after treatment and histopathologically analyzed in continuous sections. Lesions were microscopically assessed with the aid of a Leica Quantimed computer program. RESULTS: Depending on the time and dose, vaporization by the Nd:YAG laser caused large tissue defects and coagulation necrosis at energy levels over 5 W (contact and noncontact mode). Lower energy levels with tissue contact produced only superficial cell defects (<20 cell layers) but more extensive coagulation necrosis, whereas no histologic effects were observed at the same energy level without contact. In contrast, independent of delivered energy but dependent on time, Ho:YAG laser application caused pure tissue loss without relevant coagulation necrosis. The generation of small lesions (6-10 cell layers) without tissue contact was possible at energy levels under 2 J. CONCLUSIONS: Selective superficial papillary cell ablation is possible. Low-energy Nd:YAG treatment in the contact mode and Ho:YAG treatment in the noncontact mode led to superficial vaporization with no (Ho:YAG) or minimum (Nd:YAG) coagulation defects.

Animals↗

PubMed1999

Sacral anterior root stimulation and posterior rhizotomy in spastic neuropathic bladder.

The combination of sacral anterior root stimulation (SARS) and posterior rhizotomy is a successful procedure for the restoration of bladder function after supraconal spinal cord injury. Today, complete posterior rhizotomy has become part of the standard therapy. Conventional SARS leads to simultaneous activation of both the detrusor muscle and the external urethral sphincter. We evaluated the possibilities of different neurostimulation techniques to overcome stimulation-induced detrusor-sphincter-dyssynergia and to achieve physiological voiding. Selective detrusor activation improves current sacral neurostimulation of the bladder, including the "poststimulus voiding" principle. Selec-tive neurostimulation is possible in the following techniques: anodal block, high-frequency block, depolarizing prepulses, sinusoidal pulses and cryoblock. The anodal block technique and cryotechnique are excellent methods for selective bladder activation to avoid detrusor-sphinc-ter-dyssynergia and thus improve stimulation-induced voiding. Our experience has shown that future modern selective bladder neurostimulation systems will be based on either the anodal block technique or the cryotechnique.

Journal Article↗