Intravesical electrostimulation for the rehabilitation of bladder dysfunction

 

The idea of intravesical electrostimulation (IVES) dates back to 1878 when Saxtorph 1 treated urinary retention by inserting a special catheter transurethrally into the bladder, with a metal electrode inside and a neutral electrode placed suprapubically.No further publication appeared dealing with this technique until 1959 when Katona  et al.2 described their technique of intraluminal electrotherapy, initially designed for the treatment of a paralytic gastrointestinal tract. Later Katona used this method extensively for the treatment of neurogenic bladder dysfunction. Subsequently it was also applied by others with controversial results.4-17 Intravesical electrotherapy is based on the principle that in incomplete central or peripheral nerve lesions-and only these patients are suitable for this method -at lest some nerve pathways between the bladder and the cerebral centres are preserved, but are too weak to be efficient under normal circumstances. According to recent experimental studies18, IVES activates bladder mechanoreceptors. The afferent stimuli reach the spinal sacral cord via A-delta-fibres. the optimal detrusor reaction was found to be at 20 Hz (10-50 Hz); the optimal single pulse duration was 2 ms . This method follows some important principles of neurophysiology. Normally no movement begins without sensory reaction and no normal movement can proceed without feedback processes integrated in the control of movements19. Adequate sensory input-the generation of impulses in the receptors by intravesical pressure - is also the the prerequisite for conscious bladder control. Absence of efferent impulses prevents receptor - depolarization and makes them unexcitable. The initial effect of IVES is depolarization of the receptors with activation of the intramural motor system, resulting in small local muscle contractions, with further depolarize the receptor cells. As soon as this local motor reaction reaches a certain strength, vegetative afferentation ' begins: stimuli travel along afferent pathways to corresponding cerebral structures. The clinical sign of this afferentation is the occurrence of sensation. Their stimuli create centrally induced, coordinated and stronger detrusor contractions. Children, especially those with congenital neurogenic bladder dysfunction who have never experienced the urge to void, have to learn and to realize the nature and meaning of this new sensation induced by IVES. For this reason a second system must be introduced adding exteroceptive stimulation to IVES. This exteroceptive stimulation is also important for other groups of patients. It signals detrusor contractions to the patient and degree that voluntary control of the detrusor is possible. By demonstrating progress this operative conditioning serves as a positive feedback for the patient. the technique involves direct intraluminal monopolar electrical stimulation via a special catheter equipped with stimulation electrode, which is connected by a thin silver wire trough the catheter to the stimulator. Sodium chloride is used as the current-leading fluid medium in the bladder. Interestingly enough, and confirming the local effect of IVES on the receptors, its effect can be abolished by intravesical instillation of Xylocaine3,18. Exteroceptive reinforcement is achieved by visual recording of detrusor contractions on the standpipe of a water-manometer, connected to the stimulation catheter. Control of therapy comprises continuous urodynamic monitoring during IVES in order to adapt the stimulation parameters to the reaction of the detrusor. Each patient requires a highly individual stimulation programs. Moreover, intensive bladder training has to be combined with IVES outside the stimulation periods. These facts, often ignored, may explain some controversies about the effectiveness of the method. the underlying concept implies that only patients with incomplete spinal cord lesions, with receptors still capable of reacting and a detrusor able to contract, will benefit from IVES. Moreover the achievement of conscious control requires an intact cortex. IVES is applied nowadays (1) in adults with incomplete central or peripheral lesions of bladder innvervation.; (2) in neonates and children with congenital neurogenic bladder dysfunction; and (3) in patients with non - neurogenic dysfunctional voiding, especially in children. A retrospective computer analysis of the results in patients with incomplete spinal cord injury12 has shown that in one third of patients the improvement in detrusor function (sensation contractility and conscious control) has to be attributed to intravesical electrotherapy in the sense that IVES was responsible for the results. In others it may have at least facilitated bladder rehabilitation. It is also a very useful method for those with partial peripheral bladder denervation after pelvic surgery (rectum, uterus) as well for patients with voiding problems after neurosurgical operations in the couns-cauda area. Only patients with preserved pain sensation in the sacral skin dermatomes S2-S4 improved with IVES. This correlates well with the findings of Nathan and Smith, who in 1958 located the spinal pathways of micturition in the neighborhood of of the painconducting spinothalamic tract. Children with congenital neurogenic bladder dysfunction may benefit considerably from IVES3,12,14,16. So far no other method is able to induce bladder sensation and conscious micturition control in these children. However the success is limited, depending on whether nerves are preserved and the ability of the detrusor to contract. Shapiro et al20 , demonstrated that bladders from stillborn fetuses with myelomeningocele had a significant increase in the volumetric content of the connective tissue component compared to control stillborn fetuses without this anomaly. Furthermore receptor damage was present. Both of these findings may limit the effect of IVES and may thus prevent adequate bladder rehabilitation . Nevertheless in 60% of these children some form of bladder sensation can be induced by IVES and 40% conscious control of the bladder, mostly in the sense of an uninhibited neurogenic bladder of varying degree, can be achieved. Considering the findings of Shapiro it is at least questionable whether early IVES, started in the neonatal period, may improve the results; however, adequate urological care starting immediately after birth, the avoidance of chronic over-distension and recurrent urinary tract infection are prerequisites for successful IVES. IVES is also an excellent method for the rehabilitation of dysfunctional voiding, especially in children with lazy bladder syndrome. : in 17 children, who received an average of 32 stimulation's in 1-3 series over a mean observation of 14 months, 12(71%) become free of symptoms, 4(23%) significantly improved and only one did not respond. Detrusor contractility increased, the volume of residual urine decreased significantly and bladder capacity decreased. Poor detrusor contractility may be restored to normal using IVES. However, this method also has disadvantages There is no simple investigation of predictive value. The first 10-15 stimulation's have to be regarded as trial, which should be continued once a positive response has been achieved and then continued until an optimal response is achieved. IVES is time-consuming and an experienced nurse nurse and adequate facilities are needed to achieve good results. The duration of the initial therapy as well as the need for restimulation mainly depend on the underlying pathophysiology: in children with non neurogenic dysfunctional voiding the mean number of stimulation's is about 30 and the need for restimulation is rare; whereas with neurogenic bladder dysfunction intermitted long-term therapy performed at home may be necessary.

Ref.: H. Madersbacher EBU/2/13/93

References
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Intravesical Electrotherapy