J Scheepe | PubMed Health

PubMed2002

Selective block of urethral sphincter contraction using a modified Brindley electrode in sacral anterior root stimulation of the dog.

AIMS: Patients with spinal cord injury often present with dysfunction of urinary bladder and urethral sphincter. One treatment option is sacral rhizotomy and sacral anterior root stimulation with the Finetech Brindley stimulator. However, a major disadvantage is the lack of selective stimulation, resulting in simultaneous contraction of sphincter and bladder followed by unphysiological micturition. This study investigated the possibility of selective bladder stimulation by using a Brindley electrode. METHODS: In 11 male anaesthetized foxhounds, a complete posterior rhizotomy was perormed. The anterior S2 roots were stimulated with different quasi-trapezoidal (QT) pulses (pulse length range, 600-1,400 microsec; stimulation current, 0.1-2.0 mA; frequency, 20 Hz) by using a tripolar Brindley electrode. Sphincter and bladder pressures were measured urodynamically. RESULTS: All 11 animals showed a maximal reduction of the highest sphincter pressure over 80%, and in 6 of 11 trials, the sphincter pressure was inhibited completely (100%). With stimulations at maximal sphincter blockade, the average achievable bladder pressure was 33.48 cm H(2)O higher than the average sphincter pressure, and in three cases, a strong micturition was observed. Selective blockade of the sphincter was possible by applying QT pulses. The bladders remained uninfluenced by this blockade and kept their excitability at any time. CONCLUSIONS: This study shows that selective bladder stimulation with little or no coactivation of the sphincter is possible. A physiological micturition can be achieved by using a tripolar Brindley electrode. Introduction of this stimulation technique into clinical practice should not face major difficulties, considering that the device is an established electrode.

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PubMed1994

Basic experimental studies on corpus cavernosum electromyography and smooth-muscle electromyography of the urinary bladder.

In contrast to the extensive work on in vitro experiments for elucidation of the electrical properties of smooth musculature, the acquisition of knowledge on electrical signal behaviour from smooth-muscle cells in an in vivo situation remains very limited and rare. Smooth-muscle electromyographic recording from the smooth musculature of the genitourinary tract, in particular from the penile cavernous bodies and the urinary bladder, has recently become one of the most interesting issues in both impotence research as well as neurophysiological assessment of the urinary bladder. However, the inadequate available data on corpus cavernosum and EMG recordings remains controversial due to the significant discrepancy between basic physiology of the smooth musculature, technical prerequisites and the expected clinical impact from the smooth-muscle EMG of genitourinary organs. This article is an attempt to describe the fundamentals of smooth-muscle EMG signal behaviour and the technical prerequisites for data acquisition and analysis of electrical activity from smooth-muscle cells of the cavernous bodies and urinary bladder. A description is given of the technical aspects, including methodology and interpretation of the recorded data, and also of the possible interference by artefacts (endogeneous and exogeneous) that might limit the clinical relevance of this encouraging method. The advantages, pitfalls and limitations of online analogous data registration and the possibility of computer-assisted smooth-muscle electrical activity recording and analysis are demonstrated by basic in vivo studies on cavernous bodies and also the detrusor muscle.

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