Hypothesis / aims of study
Transcutaneous electrical tibial nerve stimulation (TTNS) is a non-invasive technique that has been shown to be effective in the treatment of symptoms of the Overactive bladder syndrome (OAB), demonstrating positive results in urinary habits, urodynamic values and quality of life (QoL), especially in patients resistant to drug therapy (1). TTNS is a peripheral neuromodulation, where the access to the sacral plexus is indirectly done by means of intermittent electrical stimulation of this nerve, which aims to stimulate the sacral plexus through the afferent fibers of the tibial nerve, mixed nerve containing L5-S3 fibers. The root of the S3 nerve contains sensory fibers of the pelvic floor and parasympathetic motor efferent fibers of the detrusor, as well as the pelvic sphincter and pelvic floor muscles. The stimulation of the afferent nerve can therefore lead to the activation of sympathetic inhibitory neurons and suppression of detrusor contraction through a direct sacral pathway (2). The first-line therapy for OAB suggested by the Guidelines is a behavioral therapy (BT) that includes changes in lifestyle, bladder reeducation, pelvic floor muscle training and biofeedback training (3). Considering the high prevalence of OAB in older women, the negative impact on QoL, the high use of medications, older women to opt for non-invasive, painless treatments and that do not include vaginal manipulation, and also because it is an effective conservative treatment, we opted for the use of transcutaneous electrical nerve stimulation in peripheral pathway. We conducted a pilot study to evaluate the effects of TTNS associated with BT in the treatment of OAB in older women, comparing with the effects of exclusive BT recommended treatment as Guidelines in adults.
Study design, materials and methods
This is a pilot study with randomization of two groups: G1 (behavioral therapy) and G2 (transcutaneous electrical tibial nerve stimulation associated with behavioral therapy), with blind evaluator and comparison between groups. The inclusion criteria were female gender, age between 60 and 80 years, with the presence of urinary dysfunction identified by the score greater than or equal to 8 points in OAB-V8 (Overactive Bladder Awareness Tool) questionnaire. Were excluded women with lower urinary tract infection, identified by urine test, history of treatment for OAB in the last 6 months, baseline neurological diseases, history of genitourinary neoplasia, previous pelvic irradiation, genital prolapse that exceeds the vaginal ostium, cardiac pacemaker or use of medicine for OAB. The analyzed variables of the study were urinary habit, through the bladder diary (BD) of three days, symptoms and degree of discomfort of the OAB through the ICIQ-OAB (International Consultation on Incontinence Questionnaire Overactive Bladder). The treatment of the G1 consisted of 2 sessions of BT, were passed orientations in relation to the proper positioning for urination, always seated, with legs apart, trunk forward, elbows supported on the knees and use of a foot support in order to maintain greater hip flexion; programmed urination, patients should try to postpone the urination to the maximum, trying to reach an interval of 2 hours; avoid the ingestion of liquid 2 hours before bedtime in order to avoid episodes of nocturia and avoid the consumption of irritants food and beverages to the bladder. The G2 performed 8 sessions (2x per week) of TTNS associated with 2 sessions of BT. The following parameters were fixed for electrical nerve stimulation F = 10 Hz, T = 200 µs, t = 30 min and maximum intensity tolerated by the patient. For the normality analysis, Shapiro Wilk was used with non-normal distribution for all dependent variables. The Mann-Whitney U test was used to analyze homogeneity between groups and for analysis before and after intergroup. The Wilcoxon Test evaluated the intra-group comparison analysis. A significance level of 0.05 was considered. To evaluate the power of the test used in the study was applied the post hoc analysis which demonstrated a power of 0.87 with an effect size of 2.29.
Results
Were selected by convenience, 37 older women with OAB, who were considered eligible for the study, but 7 patients were excluded by: neurological disease (2), severe genital prolapse (2), history of physiotherapeutic treatment for OAB (2) and drug treatment for OAB (1). Were randomized 30 patients, 13 in G1 and 17 in G2. However, at the end of the treatment, after dropouts and incomplete data on the evaluation forms in both groups, 19 patients were composed of the final sample (G1=8 and G2=11).
Interpretation of results
Both groups were homogeneous for sociodemographic and clinical characteristics, except for the variable quantity of pregnancies, and the G1 had a higher number of pregnancies. In intergroup comparison after treatment between G1 and G2, was not observed significant difference for all variables, except for the bother of urgency. The G2 showed significant improvement after treatment for the variables related to the symptoms and degree of discomfort assessed by the ICIQ-OAB and for the variables of nocturia and urgency urinary incontinence analyzed by BD. The G1 did not present improvement significant in any of the variables after treatment (Table I).