P.M. Braun

Activation of the supplementary motor area (SMA) during voluntary pelvic floor muscle contractions—An fMRI study

To identify cortical and subcortical regions involved in voluntary pelvic floor muscle control, functional magnetic resonance imaging (fMRI) was performed at 1.5 T in thirty healthy subjects (15 women, 15 men). The participants performed rhythmical (1 Hz) pelvic floor muscle contractions, which imitated the repetitive interruption of voiding. Since previous reports concerning the representation of pelvic floor muscles in the cortex of the medial wall are inconsistent, a conservative statistical threshold (FWE-corrected P<0.05) was used to detect the most robust foci of activation, and cytoarchitectonic probability maps were used to correlate the results with structural anatomical information. We found a strong and consistent recruitment of the supplementary motor area (SMA), with foci of peak activity located in the posterior portion of the SMA, suggesting that this region is specifically involved in voluntary pelvic floor muscle control. Further significant activations were identified bilaterally in the frontal opercula, the right insular cortex and the right supramarginal gyrus. They may reflect the attentive processing and evaluation of visceral sensations. Weaker signals were detected in the primary motor cortex (M1) and the dorsal pontine tegmentum. There was no significant correlation between bladder volumes and brain activation induced by pelvic floor muscle contractions. We found no significant gender-related differences.

Findings with Bilateral Sacral Neurostimulation: Sixty-two PNE-Tests in Patients with Neurogenic and Idiopathic Bladder Dysfunctions.

We performed bilateral PNE (peripheral nerve evaluation) tests to identify which diagnostic groups are the most likely to profit from bilateral sacral neuromodulation since the results published so far have been obtained exclusively on the basis of unilateral sacral root stimulation. In contrast to the original unilateral technique, we performed bilateral PNE test stimulation in 62 patients (36 with urinary retention symptoms and 26 with overactive detrusor; 21 with idiopathic and 41 with neurogenic bladder dysfunction) over 3–4 days. We used an advanced electrode, model #3057 (Medtronic, Inc. Minneapolis, MN). The stimulation amplitudes were adjusted individually for each side. Retrospectively, we analyzed our data according to diagnostic characteristics (retention vs. overactive bladder and neurogenic vs. idiopathic) of those patients who had positive PNE test results. The PNE test was successful in 32 patients (51.6%). Of these, 27 suffered from neurogenic bladder dysfunction; in five cases the cause was idiopathic. We conclude that bilateral PNE test stimulation with side‐specific amplitude adjustment and the use of advanced PNE electrodes led to a positive PNE result in 51.6% of the patients, which is a substantially increased response rate compared to previous studies. Of the diagnostics groups, the group with neurogenic bladder dysfunctions showed the highest response rate.

Chronische sakrale bilaterale Neuromodulation Einsatz einer minimalinvasiven Implantationstechnik bei Patienten mit Blasenfunktionsstörungen

ZusammenfassungIn der Literatur werden die Misserfolgsraten mit der von Tanagho und Schmidt beschriebenen unilateralen Stimulation mit bis zu 50% angegeben. Zur Verbesserung der Modulationseffektivität und besseren Elektrodenplatzierung und Fixation führen wir eine minimale sakrale Laminektomie mit bilateraler Elektrodenplatzierung durch.Bei insgesamt 20 Patienten wurde nach erfolgreichem PNE-Test (periphere Nervenevaluierung) ein sakraler Neuromodulator mit bilateraler Elektrodenplatzierung implantiert. Zur besseren Elektrodenplatzierung und Fixierung wurde eine minimal-invasive Laminektomie durchgeführt.Bei den Patienten mit Detrusorinstabilität reduzierten sich die Inkontinenzepisoden von durschnittlich 7,2 auf 1 pro Tag, die Blasenkapazität stieg von 198 auf 352 ml. Bei den Patienten mit hypokontraktilem Detrusor reduzierten sich die Restharnwerte von 450 auf 108 ml. Der maximale Detrusorkontraktionsdruck während der Miktion stieg von 12 auf 34 cm H2O.Mit der bilateralen sakralen Neuromodulation und mit der von uns entwickelten Implantationstechnik sind optimale Ergebnisse bei Patienten mit therapierefraktären Detrusorinstabilitäten und Patienten mit hypokontraktilem Detrusor zu erzielen.AbstractThe implantable neuromodulation system described by Tanagho and Schmidt enables unilateral sacral nerve stimulation. Reports have been made on sacral neuromodulation failures of up to 50% in patients undergoing this procedure. We chose the bilateral electrode implantation and a minimal invasive laminectomy to ensure a more effective modulation and better placement and fixation of the electrodes.After successful assessment using a peripheral nerve evaluation test, 20 patients (14 with detrusor instability, 6 with hypocontractile detrusor) underwent minimally invasive laminectomy and bilateral electrode placement. In the patients with detrusor instability, the incontinence episodes were reduced from 7.2 to 1 per day and the bladder capacity improved from 198 to 352 ml. In patients with hypocontractile detrusor, the initial residual urine level of 450 ml dropped to 108 ml. Maximum detrusor pressure during micturition rose from 12 cmH2O initially to 34 cmH2O. The average follow up period was 17.5 months. There was no sign of deterioration in the modulation effect in any of the patients.Bilateral electrode implantation and the new sacral approach allow optimal neuromodulation in patients with bladder dysfunction. Laminectomy enables optimum electrode placement and fixation with minimal trauma.

Botulinumtoxin in der Therapie der überaktiven Blase – ein Überblick

This article shall give a state-of-the-art review about the treatment of neurogenic and idiopathic detrusor overactivity with botulinum toxin injections into the detrusor muscle. We searched PubMed for original articles up to December 2006. Abstracts published at international congresses were also considered if they provided substantial new information. Based on this review it appears that a majority of patients with spinal cord injury regains continence after botulinum toxin A injection and that in children with myelomeningocele a significant improvement in continence can also be achieved. A concomitant reduction of intravesical pressure protects the upper urinary tract in these patients. In idiopathic detrusor overactivity, injection of botulinum toxin A also resulted in improvement of continence and reduction of daily micturition frequency. For both indications a high success rate could be achieved with an average duration of the effect of 6 months. Repeated injections into the detrusor seem to have no adverse effects in terms of duration or strength of the effect. Side effects were marginal and systemic side effects were experienced only in individual cases; in some patients with idiopathic detrusor overactivity intermittent self-catheterization was required. Overall intradetrusor injections of botulinum toxin seem to be a new, highly effective, and safe alternative in the treatment of neurogenic and idiopathic detrusor overactivity.

Bladder wall tension during physiological voiding and in patients with an unstable detrusor or bladder outlet obstruction

To develop and evaluate a new clinical method for measuring bladder wall tension (BWT) on detrusor contraction during physiological voiding and under pathological conditions, as in experimental trials during subvesical obstruction the ability to generate pressure increases, whereas the contractile force per cross‐sectional area of detrusor muscle decreases.

Ätiologie und Pathophysiologie der Belastungsinkontinenz beim Mann

ZusammenfassungDie Belastungsinkontinenz ist eine seltene Erkrankung des Mannes. Mit einer durch die verbesserte Diagnostik der Prostataerkrankungen steigenden Anzahl von durchgeführten Operationen an der Prostata kommt es innerhalb der letzten Jahrzehnte zu einem konsekutiven Anstieg der von einer Belastungsinkontinenz betroffenen Männer. Als die vom Patienten – als auch vom Operateur – am meisten gefürchtete operationsbedingte Nebenwirkung ist die Inkontinenz einer der wichtigsten Faktoren in der Therapie der betroffenen Patienten. Eine eingeschränkte Kontinenzleistung bedeutet eine nicht unerhebliche Einschränkung der Lebensqualität der betroffenen Männer und deren Partner.Wenig bekannt ist über die pathophysiologischen Ursachen einer iatrogen verursachten Belastungsinkontinenz, von der vermutlich eher ältere als junge Männer betroffen sind. Die heutigen Kenntnisse stützen sich auf einige wenige klinisch experimentelle Studien.Neben der direkten myogenen oder neuronalen Schädigung des Schließmuskels scheinen eine nicht ausreichende Länge der funktionellen Urethra und eine gestörte Blasenfunktion wichtige Ursachen für das Auftreten einer postoperativen Inkontinenz zu sein. Zur Verbesserung der postoperativen Kontinenz nach radikaler Prostatektomie wurden verschiedene operative Modifikationen eingeführt. Der Erhalt des Blasenhalses, Schonung der puboprostatischen Bänder und der Gefäßnervenbündel sowie das Belassen der Samenblasenspitzen scheinen einen positiven Effekt auf die postoperative Kontinenzleistung zu haben.AbstractStress urinary incontinence is rare in men. Despite the improvements in diagnostic approaches to prostate diseases and surgical interventions on the prostate, stress incontinence has tended to increase in recent decades. The most frightening operative complication for both the patient and the surgeon is incontinence, which is one of the important factors in the treatment of the affected patients. The limited degree of continence considerably lowers the quality of life for the affected men and their partners.There is little information available about the pathophysiology of iatrogenic stress incontinence, which more likely affects older men rather than young men. The available information is based on a few experimental studies.Besides the direct damage to the muscular or neurological component of the external sphincter, insufficient length of the functional urethra and impaired bladder function seem to play an important role in the genesis of postoperative incontinence. In order to improve the postoperative continence status after radical prostatectomy a number of different operative modifications have been introduced. Preservation of the bladder neck, puboprostatic ligaments, and the neurovascular bundle as well as leaving the tips of the seminal vesicles seem to have a positive impact on the degree of postoperative continence.

Stimulation signal modification in a porcine model for suppression of unstable detrusor contractions

OBJECTIVES To investigate, in an experimental study, the efficacy of a different stimulation signal in a porcine model to suppress formalin-induced unstable detrusor contractions. The current mode of stimulation in peripheral nerve evaluation tests and sacral neuromodulation is based on rectangular signal shapes. Published reports, however, have revealed that up to 80% of patients do not respond to peripheral nerve evaluation stimulation. METHODS After placement of electrodes at S3 in 12 anesthetized Göttinger minipigs, unstable contractions were induced by intravesical instillation of formalin. Ten-minute stimulation phases with a quasi-trapezoidal signal and a rectangular signal followed. An interval of 30 minutes elapsed between the two series of stimulations. The pressure values were registered on a urodynamic unit and evaluated as contractions and amplitudes per minute. Six minipigs were treated in the same way but were not stimulated and served as the control group. RESULTS After formalin instillation, the average number of involuntary detrusor contractions was 3.5/min (+/- 0.8) and the sum of amplitudes was 7.2/min (+/- 1.1). Subsequent NaCl instillation and quasi-trapezoidal stimulation reduced the contractions to 0.3/min (+/- 0.3) and the sum of amplitudes to 0.8/min (+/- 0.4). A contraction rate of 1.1/min (+/- 0.1) and a sum of amplitudes of 5.1/min (+/- 2.4) were recorded under stimulation with a rectangular signal. In the control group, no significant reduction was recorded. CONCLUSIONS The acquired data demonstrate that quasi-trapezoidal stimulation suppresses unstable detrusor contractions in the minipig more effectively than does conventional rectangular stimulation as presently applied in sacral neuromodulation.

Improved sacral neuromodulation in the treatment of the hyperactive detrusor: signal modification in an animal model.

To investigate different stimulation signals for the peripheral nerve evaluation test (PNE, carried out before implanting a sacral neuromodulator for functional voiding dysfunction) in an animal model and to determine their efficacy, as up to 80% of patients do not respond to the PNE test.

Impact of Electrostimulation of Neurovascular Bundles and Pudendal Nerves on the Membranous Urethra in Male Rabbits

PURPOSE The pathophysiology of post-prostatectomy incontinence is supposed to be multifactorial. The impact of the neurovascular bundles on sphincter function is still under debate. We clarified the impact of cavernous nerves function on the MU. We compared MU pressure responses in male rabbits following electrophysiological stimulation trials on the neurovascular bundles vs pudendal nerve stimulation. MATERIALS AND METHODS Six male Chinchilla Bastard rabbits were included in this study. Pudendal and cavernous nerve branches were exposed bilaterally in all animals. Randomized electrostimulation of pudendal nerve fibers and the cavernous nerves, as confirmed by erection,) were done using a biphasic signal form of 0.3 mA for 200 microseconds. Stimulation frequency was changed in a randomized pattern from 10 to 40 Hz. Changes in MU pressure were measured urodynamically via a transurethral microtip catheter placed in the MU. Stimulation responses of the 2 nerve structures were compared. RESULTS Mean baseline pressure in the MU without stimulation was 23 cm H(2)O (range 20 to 25) in all animals. During unilateral pudendal stimulation the mean pressure response increased highly significantly to 33, 43, 59 and 60 cm H(2)O at 10, 20, 30 and 40 Hz, respectively (p <0.005). In contrast, compared to baseline pressure cavernous nerve stimulation did not result in any significant changes in proximal urethral pressure (mean 23 cm H(2)O, range 20 to 25, p >0.05). CONCLUSIONS Our results confirm the primacy of the pudendal nerve in the external urethral sphincter innervation. In contrast, stimulation of the cavernous nerves did not produce any pressure changes in the MU. These results confirm that the neurovascular bundles have no functional impact on the MU.

[Botulinum toxin in the treatment of benign prostatic hyperplasia : an overview].

The aim of this article is to provide a state-of-the-art review about the treatment of benign prostatic hyperplasia with botulinum toxin injections into the prostate. We searched PubMed for original articles until July 2007. Abstracts published at international congresses were also considered if they contributed substantial new information. Injections were performed mostly via the transperineal route under local anesthesia.From this review it appears that a majority of patients with benign prostatic hyperplasia experiences an improvement of both subjective parameters (IPSS, AUA symptom score) and objective parameters such as peak flow rate, postvoid residual volume, and prostate volume. An effect could be shown for different patient groups including different prostate sizes and different symptom characteristics. A high success rate and sustained duration of the effect of at least 12 months could be achieved. Side effects were marginal, and no systemic side effects were reported.Placebo-controlled studies with sufficient patient numbers and long-term follow-up are needed to determine the future value of this procedure in the treatment of patients with benign prostatic hyperplasia.