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       Posterior tibial nerve stimulation in the management of
       overactive bladder: A prospective and controlled study
     Patricia O. Bellette, Paulo C. Rodrigues-Palma, Viviane Hermann, Cássio Riccetto, Miguel
                                      Bigozzi,Juan M. Olivares

 Servicio de Urología de la Facultad de Medicina de la Universidad estatal de Campinas-Unicamp. Brasil.

                           ACTAS UROLÓGICAS ESPAÑOLAS 2009;33(1):58-63



                                                    Abstract
The aim of this study was to evaluate the efficacy of posterior tibial nerve stimulation in
women with overactive bladder symptoms and the impact on the quality of life using the
Overactive Bladder Questionnaire (OAB-q).
Methods: Thirty-seven women from the female urology outpatient clinic of the Hospital das
Clínicas de Campinas (HC/UNICAMP) were enrolled in this prospective, controlled and
randomized clinical trial. The patients were randomly assigned to one of two groups:
Treatment group: patients were submitted to posterior tibial nerve electrical stimulation
(n=21) and Sham group: patients had electrodes placed without electricity (n=16). After
informed consent, the patients underwent a physiotherapeutic evaluation that included a
voiding diary and the overactive bladder questionnaire (OAB-q). The treatment schedule
included eigth sessions of posterior tibial nerve electrical stimulation twice a week.
Results: There were significant changes in symptoms such as frequency and nocturia
(p=0.003 and p=0.001). Urgency and quality of life were improved in both groups after
treatment.
Conclusion: Posterior tibial nerve electrical stimulation is an effective treatment in overactive
bladder.
Keywords: Posterior Tibial Nerve Electrical Stimulation; Overactive Bladder; OAB-q.



INTRODUCTION
Overactive bladder (OAB) is defined by the International Continence Society (ICS) as a cluster
of symptoms suggestive of lower urinary tract dysfunction. It is a clinical condition in which the
patient reports the presence of urinary urgency, associated or not with urgency incontinence,
usually accompanied by frequency and nocturia1.
The estimated prevalence of OAB varies considerably according to different studies, ranging
from 3% to 43% of the population1,2. In a prevalence study conducted in Brazil, Teloken3 found
that 23.2% of women had irritative symptoms of OAB.
The approach to the patient with overactive bladder has the objective of controlling the clinical
symptoms presented and providing an improvement in the patient’s quality of life through
medication, intravesical therapies, neuromodulation or physiotherapy.
Posterior tibial nerve stimulation using surface electrodes was proposed by McGuire4 in 1983. In
1987, Stoller et al.5 demonstrated in apes that intermittent peripheral stimulation of the posterior
tibial nerve (SANS) could inhibit overactive bladder and urgency incontinence. Subsequently,
Amarenco6 used this type of electrical stimulation in the treatment of overactive bladder via
surface electrodes, and observed in the urodynamic study that bladder capacity was increased
and that the occurrence of involuntary detrusor contractions was delayed.
The aim of this prospective controlled study was to evaluate the impact of transcutaneous
posterior tibial nerve electrical stimulation on the quality of life of women with clinical symptoms
of OAB who were submitted to treatment versus the group with sham treatment using the
Overactive Bladder Questionnaire (OAB-q SF).
                                                                                                   2


MATERIALS AND METHODS
Thirty-seven women with clinical symptoms of OAB were selected from the female urology
outpatient clinic of the Hospital das Clínicas de Campinas (HC/UNICAMP). The patients were
separated into two groups: 21 patient in the treatment group and 16 patients in the placebo
group (electrodes placed but the device was turned off).
The study inclusion criteria were age 18 to 85 years, presence of overactive bladder symptoms
for more than six months, urinary frequency greater than eight micturitions per day, episodes of
nocturia and/or urinary urgency. The exclusion criteria were pregnant women, neurological
problems, pronounced dystopias (stage II or III in the ICS definition), urinary infection and stress
urinary incontinence.
The study methods consisted of a physiotherapeutic evaluation and electrical stimulation
treatment. The women were questioned about the history of their symptoms, previous surgeries,
presence of menopausal symptoms, urinary frequency, urinary urgency and nocturia, as
demonstrated by the voiding diary for three days. The OAB-q quality of life questionnaire was
answered at the initial evaluation and at the end of treatment.
The treatment consisted of 8 sessions of transcutaneous posterior tibial nerve electrical
stimulation with a Dualpex 961device twice a week with a duration of 30 minutes in each
session, and with positioning of the electrodes according to Amarenco6.


RESULTS
Age, presence of menopausal symptoms, previous surgeries for urinary incontinence and
duration of symptoms did not show differences between the two groups. The age of the women
who participated in this study was 47.73 years±10.90). At the time of evaluation, 23 (62.16%)
were menopausal, 4 (10.81%) had a history of previous surgery for urinary incontinence, and
none was on pharmacological treatment for OAB. The mean duration of OAB symptoms was
6.86 years ±7.06).
Urinary urgency was present in 15 (93.75%) women in the placebo group at the initial
evaluation but in only 10 (62.5%) at the final evaluation (p=0.025). In the treatment group, 19
(90.48%) women had initial complaints of urgency, but only 9 (42.86) maintained their
complaints in the final evaluation (p=0.002) (Table 1).


                                             Table 1
      Percentage of women with urinary urgency before and after treatment in each group.

                          Placebo                 P value*         Treatment (%)        P value*
                         (%)(N=16)                                    (N=21)
     Initial                93.8                                        90.5
     Final                 62.50                    0.025               42.9             0.002
*McNemar test


Urinary frequency in the placebo group was 13.88 micturitions per day at the initial evaluation
and 10.55 at the final evaluation. The treatment group had 11.35 micturitions per day at the
initial evaluation and 8.29 at the final evaluation. These results were analyzed by the ANOVA
test, which showed that the reduction in urinary frequency was statistically significant in the
treatment group (p=0.003). At the end of treatment, the treatment group had lower values for
urinary frequency when compared to the placebo group (p=0.009) (Figure 1).
                                                                                               3




                          FUGURE 1: change in urinary frequency


Nocturia also showed a reduction over the treatment period. Nocturia decreased from 2.56 to
2.06 micturitions per night in the placebo group and from 2.38 to 1.14 micturitions per night in
the treatment group. The results for nocturia were analyzed by the ANOVA test and showed
significant differences in the treatment group (p=0.001), indicating a tendency to improvement in
this group (p=0.054) compared to the placebo group (Figure 2).




                                FIGURE 2: change in nocturia


The parameters evaluated on the OAB-q were severity and total score.
                                                                                                                    4

Initial and final scores for severity were 67.47 and 51.21 in the placebo group and 68.55 and
31.72 in the treatment group. Both groups analyzed showed a statistically significant
improvement (p<0.001), but the treatment group improved more than the placebo group
(p=0.018) (Table 2 and Figure 3).


                                                       Table 2
                                    Change in severity score on the OAB-q
                    Placebo         ±DP         Treatment         ±DP          P value1      P value2     P value3
Initial OAB-q         67.47         20.68          68.55          18.90
Final OAB-q           51.21         32.11          31.72          18.25           0.162       <0.001        0.018
Delta t              -16.26         26.24         -36.03          25.33
2
 ANOVA: significant differences between times (Profile): T1≠T2 for both groups.
3
 ANOVA: significant differences between groups (Tukey): Placebo≠treatment at T2.




                           FIGURE 3: Change in severity score on the OAB-q


The change in the total score was from 50.93 to 66.63 in the placebo group and from 52.25 to
83.99 in the treatment group. Both groups analyzed showed a statistically significant
improvement (p<0.001), but the treatment group improved more than the placebo group
(p=0.037) (Table 3 and Figure 4).


                                                       Table 3
                                      Change in total score on the OAB-q

                        Placebo         ±DP       Treatment        ±DP       P value1     P value2      P value3
    Initial OAB-q         50.93         17.42         52.25        18.62
    Final OAB-q           66.63         25.06         83.99        16.99       0.085      <0.001         0.037
    Delta t               15.71         19.46         31.73        23.44                                 0.023
    2
    ANOVA: significant differences between times (Profile): T1≠T2 for both groups.
    3
    ANOVA: significant differences between groups (Tukey): Placebo≠treatment at T2.
                                                                                                   5




                        FIGURE 4: Change in total score on the OAB-q


DISCUSSION
In this controlled and “quasi” randomized clinical trial, quality of life and overactive bladder
symptoms were compared in two groups of women. The treatment group, submitted to
transcutaneous tibial posterior nerve electrical stimulation, and the “placebo” group.
The negative impact on quality of life is well known among with overactive bladder. To reduce
this impact, they choose to change their lifestyles, adjust their travel plans, look for places with
easy access to bathrooms, and often restrict their fluid intake.
The use of generic or specific questionnaires as instruments to evaluate quality of life has
intensified in recent years due to the great interest in subjective clinical evaluation to assess the
patient’s opinion about her state of health. These are important to fill a gap existing between
objective evaluation, such as the voiding diary, the pad test and the urodynamic study, which
reflect the severity of urine loss, but do not express the changes in daily activities.
In this study, the Overactive Bladder Questionnaire (OAB-q) was used because it is a disease-
specific questionnaire and thus is more sensitive to detect the clinical signs of overactive
bladder.
Quality of life analyzed by the OAB-q was shown to be an effective tool to discriminate the
impact of overactive bladder on quality of life. The results decreased significantly in both groups
over time, but the improvement was significantly greater in the treatment group.
Posterior tibial nerve electrical stimulation was chosen as the physiotherapeutic method
because it is an interesting alternative for the treatment of overactive bladder, which is effective
and without side effects9.
On the other hand, despite the fact that pharmacological treatment is currently the first option
for the treatment of women with clinical symptoms of overactive bladder, adherence to
treatment is low, especially due to side effects which lead to discontinuation in 60% of
cases10,11.
Posterior tibial nerve electrical stimulation is considered to be a simpler, less invasive and easy
to apply form of peripheral sacral stimulation that is well tolerated by patients and more
affordable9.
However, there are few prospective and comparative studies in the literature, especially using
specific tools and adequate statistical analyses.
The results presented here are a basic proposal on doubts about the techniques recommended
by physiotherapists. These doubts are frequent, especially on placement of the electrodes,
types of current, results obtained and impact on the woman’s quality of life.
All women were submitted to eight sessions of therapy, all the questionnaires were completed,
and none of the women failed to attend the sessions more than 3 times. The reasons for
missing sessions were very variable, but did not alter the results of the study. The evaluations
                                                                                                 6

were carried out by the investigator or the physiotherapist, and treatment was performed by the
same person who evaluated the patient, thus creating a bond with the physiotherapist.
Frequency and nocturia were significantly decreased in the treatment group, showing the
superiority of this group over the placebo group. This study found that urinary frequency was
normalized in women in the treatment group from 11 to 8 micturitions per day These results
were analyzed by the ANOVA test, which showed a statistically significant reduction in urinary
frequency in the treatment group (p=0.003). At the end of the evaluation, the treatment group
had lower values for urinary frequency compared to the placebo group (p=0.009).
The studies by Van der Pal et al.12 also observed a reduction in the number of micturitions per
day, in addition to a reduction in the pads used in episodes of urine loss. Fall13 (1985) used this
resource in the treatment of interstitial cystitis, obtaining good results in symptoms and a longer
interval between micturitions. When the variable nocturia was evaluated, we observed that
women in the treatment group had a reduction from two to one episode per night, which was
considered a normal value (p=0.001).
The literature shows that nocturia is one of the symptoms that causes more impact on quality of
life. Coyne7 (2003) used the OAB-q to evaluate the impact of symptoms of nocturia on quality of
life and observed an interference with sleep and social interaction.
Urgency, the main symptom of overactive bladder, was present in approximately 90% of the
women included in this study. Women who did have this symptom were included because they
had and increase in urinary frequency and nocturia.
The results showed that tibial nerve stimulation was effective in both group, when the variable
evaluated was urinary urgency. Urgency was reduced in the treatment group from 90% to 43%
(p=0.002) and in the placebo group from 93% to 62.5% (p=0.025).
McGuire4 (1983), in his study of 22 women with clinical symptoms of overactive bladder, found
12 (55%) continent women and 7 (32%) with improvement after treatment with electrical
stimulation of the posterior tibial nerve.
In this study, we observed improvement in about 50% of patients in the treatment group. These
results are in agreement with the literature where studies reported improvement rates of about
50% to 70% of patients8,9.
We can explain this improvement through the study by Amarenco6 (2003), where an increase in
bladder capacity and a delay in the occurrence of involuntary detrusor contractions was
observed during the urodynamic evaluation. The two factors may act to reduce the urinary
urgency shown by women.
Irwin et al.13 (2005) observed in her study that 32% of persons interviewed with symptoms of
overactive bladder had symptoms of depression and 28% had symptoms of stress. In addition,
76% reported that symptoms interfered negatively with their daily life.
The OAB-q quality of life questionnaire was shown to be a sensitive questionnaire to detect the
clinical symptoms of overactive bladder and their impact on the quality of life of affected women.
The improvement in quality of life after percutaneous posterior tibial nerve stimulation was
significant for both the severity score and the total score on the OAB-q in both groups, in
agreement with the literature.
Both the treatment group and the placebo group showed improvement in quality of life scores,
severity scores and total scores (p<0.05), but the treatment group showed superiority to the
placebo group in both severity (p=0.018) and total scores (p=0.037). In some studies, quality of
life and clinical symptoms of overactive bladder were evaluated after treatment with posterior
tibial nerve stimulation using other questionnaires, such as the SF-36 and IQOL9,12. In these
studies, improvement in quality of life was the key criterion to consider treatment successful.
In this study, we found an improvement in symptoms in approximately 30% of women in the
placebo group, which is in agreement with the results found in pharmacological studies, where
an improvement was shown in approximately 30% of patients with the placebo effect.


CONCLUSION
Posterior tibial nerve electrical stimulation was an effective, safe and noninvasive treatment that
significantly improved the OAB symptoms and quality of life of the patients.
                                                                                                7


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Correspondence author: Dr. Paulo Palma
Servicio de Urología de la Facultad de Medicina de la
Universidad estatal de Campinas–Unicamp.
Rua Jose Pugliasi Filho 265
Campinas, São Paulo, Brasil 13085-415
Author e-mail: ppalma@uol.com.br
Paper information: Original – Female urology - Incontinence
Manuscript received: february 2008
Manuscript accepted: september 2008

				
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