Discussion
In the literature, TTNS treatment has been performed with different protocols and the number of sessions. Souto et al. performed TTNS twice a week for 12 weeks while Booth et al. performed the procedure for six weeks (9, 16). Svihra et al. performed it once a week for 12 weeks while SillĂ©n et al. performed TTNS every day, and LordĂȘlo et al. three times a week (10, 11, 12). Finazzi et al. 35 patients with resistant OAB performed PTNS once a week and 3 sessions a week. They reported that the procedure performed once a week and 3 times a week did not change the effectiveness. But, that many sessions enabled the early onset of the treatment effect. (13). Thomas et al. reported that TTNS performed every day in fecal incontinence gave better results than twice a week (14). Also, we performed TTNS once a week and three times a week for 12 weeks in two different groups. We have demonstrated that three times a week sessions increased the treatment response and improves the symptoms earlier. Our study showed that we achieved a similar success rate to literature with three sessions per week in refractory OAB.
TTNS, PTNS, and other electrical stimulation methods, Botulinum toxin-A (BoNT / A) and sacral neuromodulation (SNM) are frequently used in OAB patients who do not respond to behavioral therapy and anticholinergic therapy. Although BoNT / A and SNM are more effective methods, they have more side effects. (17, 18). However, TTNS has no side effects. Also, TTNS has been used in many studies in the literature due to its ease to perform, being feeled less pain and low cost (19).
TTNS showed similar effectiveness with PTNS in studies (19, 20). Urge and voiding frequency, number of nocturia, frequency of incontinence, OAB scores were used to evaluate the effectiveness in related studies (19, 20, 21). Also, more than 50% reduction in urge incontinence episodes was accepted as the complete response in studies. (22, 23, 24). Very different success rates have been reported in the literature. Ammi et al. showed 53% success after one month of TTNS in resistant OAB cases (23). Welk et al. found success in only 15% of patients with OAB (24). Considering this wide range of outcomes, we achieved a complete response in the groups with 23.1% and 45.5% success rates, respectively. We think that the difference between our study and the literature in terms of complete response rates may be related to the small size of the study groups, the different characteristics and symptom severity of the patients in the study groups. The complete response to treatment may increase if anticholinergic treatment is given together with TTNS. Randomized double-blind placebo-controlled studies with a high number of patients are needed to evaluate the true success of TTNS treatment. Welk et al. also pointed out the high risk of bias in the studies in
a single stimulator due to budget constraints. This situation created difficulties for the patients due to the obligation to come to the hospital for 12 weeks. The ideal practice for TTNS would be to have the first session is performed in the hospital in the presence of a specialist and then the patient continues to be treated at home. Thus, patient satisfaction will increase and the loss of time and money will decrease.
In our study, the low number of patients, the absence of a urodynamic study for objective comparison before and after treatment, and the absence of a placebo control group are limitations. Also, we evaluated treatment success subjectively with symptom scores and satisfaction questionnaires. However, the voiding frequency, the number of urge incontinence episodes, and the frequency of nocturia in the voiding diary were considered objective data. Also, there are no criteria based on objective data regarding the duration of treatment and the number of sessions per week. We also think that our study contributes to the literature to determine the ideal treatment protocol of TTNS. Also, randomized, placebo-controlled studies with large patient groups evaluated with urodynamic data are needed to develop an ideal treatment scheme.
Conclusion
We have shown that women with refractory OAB are observed to early improvements in the symptoms as the number of sessions increases. However, it did not change the final treatment success. In the future, we think that TTNS may become widespread as a method that can be applied easily and at a low cost at the home of patients before invasive procedures in refractory OAB.
Conflicts of interest: The authors declare no conflict of interest.
Funding: All authors have no direct or indirect commercial financial incentive associated with publishing the manuscript. Also the authors received no financial support for the research and/or authorship of this article.