obtained a success rate of 64% in a group of patients with

idiopathic detrusor instability 2 years after treatment,

while ali patients with multiple sclerosis who initially had

benefitOO fram treatment relapsed within 2 months

(although daily treatment of these patients at home

was useful). Disappointing results have also been

obtainOO in patients with spinal cord injury and elderly

cognitively impairOO nursing-home patients [24,25].

Careful patient selection is crucial for good results and

maximal electrical stimulation should not be usOO as a

last resort [12]. However, failure of previous pharmaco-

logical treatment does not excIude a good response

beforehand [16,23].

Treatment scheme and parameters. The intensity of

stimulation should be as high as possible. Geirsson and

FalI [12] noted that the results obtained with a routine

outpatient procedure were far less good than those

obtainOO in their prospective research series. They

hypothesized that this was partly because the routine

procOOure was undertaken by a nurse With no doctor

present; in the presence of a doctor. it is usually easier to

persuade a patient to accept a high stimulation intensity.

These authors also notOO that the most successful resuIts

publishOO were obtainOO io series using a stimulation

frequency of "'" 20 Hz, while physiologically frequencies

of 5-10 Hz are optimal in inhibiting the bladder. Possibly

a higher frequency permits a higher stimulation inten-

sity, as not every single pulse is detected. No data are

available on the minimum number of treatments

required. Primus and Kramer [23] found that some

patients did not improve until the fifth treatment, and

recommended treating patients at least 10 times.

Intuitively, it may be expected that treatment on a

daily basis wiIl be more effective than weekIy treatment;

this hYJ?Othesis has not been tested. Siegel et alo [26]

found no significant difference between daiIy and every-

other-day treatment.

Long-term effectiveness.. Few studies .reported success

rates after a foIlow-up of > 6 months; of the 17 patients

treated by Yamanishi et aI. [20], seven remained curOO

for at least 9 months on average after stimulation with

no intervention, while another six achievOO control with

re-treatment. After a 2-year foIlow-up, 64% of 45

patients with idiopathic detrusor iostability [23] stilI

reportOO subjective satisfaction; several needOO re-treat-

ment sessions and the remaining patients had relapsOO.

The success rate of 8 5% initiaIIy obtainOO by Eriksen et aI.

[16] in 48 women with idiopathic problems declinOO to

77% after 1 y"ear. Bratt et alo [27] traced these patients

after 10 years; 27 were evaluable and symptoms of urge

incontinence were reportOO by 78%. However, 30%

leaked only once a week or less; 60% were satisfied with

maximal electrical stimulation and would recommend it

to a friend.

Síde-effects. No severe side-effects have been reported;

local pain and diarrhoea disappear after a brief pause

in therapy [18]. Mucosal irritation seldom occurs; the

lesion quickly heals during a temporary break in

the treatment [2].

Transcutaneous electricaI nerve stimulation

TENS is usOO widely in the treatment of pain in a variety

of conditions. Fali et aI. [28] successfulIy treatOO patients

with interstitial cystitis. using surface electrodes attached

over the suprapubic area.

Technique. In treating the overactive bladder, the

electrodes are usually attachOO over the S2 and S3

dermatomes (peri-anal region) or over the sacral

foramina S2 and S3 (Fig.2). Stimulation takes place

for 20 mio to several hours daiIy during one or more

weeks. The intensity of stimuIation shouId not exceed

the leveI of discomfort.

Evidence. Acute cystometric effects of TENS have been

shown in patients with an unstable bladder [29,30]. The

effects in patients with sensory urgency were uncertain;

the bladder volume at first desire to void increasOO

significantIy with TENS over the suprapubic region, but

not with TENS over the S2 to 83 sacral foramina. Bladder

capacity did not respond at both sites in these patients

[30]. However, of the patients treated by Walsh et aI.

[31], 76% and 60% reported an improvement in daytime

frequency and urgency, respectively, while 56% noted a

rOOuction of nocturia. Most of these patients had sensory

urgency. Hasan et aI. [29] found that urinary frequency

FIg. 2. TENS In a chUd with clcctrodes stuck over the sacra!

foramlna.