provoked unstable conrractiuILS ín idwpathic and neuro-

genic patients [54. 56}. Stimwation also abolished the

sensation af urgency. Yamanishi tr aI. [53] campared the

acute cystametric elTects of magnetíc stimulation with

those of anogenítal electrical stimulation: the ínhíbition

af detrusor overacti\':ity was greater with magnetic

stimulation. The same graup of authors treated eight

patients with urge íncontinence. mainly neurogenic [55].

The mean ($O) bladder volume at first desire to void and

maximum cystometric capacity increased considerably

from 160 (101) to 277 (52) mL. and fram 211 (91) to

336 (35) rnL. respectively; the latter change was sig-

nificant. Clinically. síx patients were considered cured or

improved. Daytíme voíding frequency and the number af

daytime [eakages significantly decreased from 9.5 (2.8)

to 8.1 (3.5). and from 3.1 (3.1) to 1.5 (1.2). respectively.

Long-ternz ejJectíveness. No data on patients with pure

urge incontinence are available. Sand et aI. [57] treated

76 women with mixed incontinence; considering only

those women with no identified risk factors. 11 of 16 had

a > 50% improvement in the number af íncontinence

episodes per day at 2 weeks after therapy. while eight of

14 did so at 18 weeks.

Side-ejJects. Magnetic stimulation normally causes no

serious discomfort; there were two idiopathic patients

who found stimulation painful or uncomfortable. while

a neurogenic patient had an uncontrolled bowel

evacuation [54.56].

lntravesical transurethral electrostimulation

Intravesical e!ectrical stimulation is based on direct

activation of receptors in the bladder and aims to enable

the patients to recognise urge; it cannot be considered

a kind of neuromodulation. However. the method so

c!osely resembles most neuromodulation techniques that

a brief description is appropriate.

Techníque. A special catheter equipped with a stimula-

tion electrode in its tip is ínserted transurethrally into the

bladder. which is partially filled with saline. a conducting

fiuid. A ground pad is placed on an arm or lego One port

of the catheter is connected to apressure monitor. so

that the patient can corre!ate their sensations with

the behaviour of the bladder (biofeedback). Treatment

usually takes place five times per week for 3 weeks. with

one session taking 60-90 tnin.

Evídence. Intravesical stimulation was introduced

several decades ago with the aim of improving bladder

sensation ánd' blàdder emptying in patients with a

neurogenic bladder, especially children. It follows from

this aim that only patients ín whom at least some neural

pathways between the bladder and the cerebral centres

are preserved are suitable candidates. The method ís stil!

used in these patients, but it is controversial [58,59].

Application af the method in patients with an overactive

bladder is relatively new. The rationale is that these

patients may learn to recognize involuntary contractions

and inhibit them by squeezíng the pe!vic fioor. Risi et a/.

[60] treated 162 patients. reparting an improvement in

urinary continence in 25 of 33 with myelomeningocele.

but the treatment failed in 75% ofthe remaining patients.

The authors therefore advised against intravesical

e!ectrostimulation in idiopathic cases.

Conclusions

Neuromodulation is a valuable treatment option for

patients with an overactive bladder. The non-surgical

techniques can be applied as an aIternative to standard

conservative treatment. or may be tried if such a

treatment fails. Sacral neuromodulation should be

considered before using a more invasive operatian such

as bladder augmentation. It is unc!ear to what extent

the various techniques are interchangeable. Le. it is

unknown whether a technique that is or is not eíiective

in a patient can be successfully replaced by another

technique. because no variables predictive of success

have been identified. The detertnination of reliable

selection criteria would be a major advance; a better

understanding of the mechal1ism of action tnight

contribute considerably to this goal.

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