Currently, the European and American guidelines and international organizations related to genitourinary diseases define three main lines of treatment for patients with overactive bladder (OAB): a) Behavioral therapy, b) Pharmacological therapy and c) Nerve neuromodulation tibial, use of sacral neuromodulator and/or application of intravesical botulinum toxin. Comparisons with anticholinergic therapies are of particular interest with respect to tolerance of side effects and cost-effectiveness. The high financial and resource cost raises modalities such as posterior tibial nerve stimulation (TTNS) therapy as a valuable and well-tolerated alternative that can be self-administered by the patient at home. The socioeconomic effect of overactive bladder compared to the cost of treatment provides a more cost-effective idea for this group of patients.

Objective: To evaluate the use of combined therapy (Tolterodine and transcutaneous electrostimulation of the tibialis posterior) as the most effective for the management of overactive bladder syndrome, compared to isolated therapy of tolterodine or electrostimulation of the tibialis posterior, in patients who do not respond to behavioral therapy and pelvic floor exercises.

Material and Methods: A prospective clinical trial was carried out where a total of 60 patients treated in the Gynecological Urology outpatient clinic were studied, who met the current criteria for overactive bladder established by the ICS (International Continence Society). Using computer-generated numbers, cases were assigned to a first group (GI=Tolterodine), a second group (GII=Transcutaneous electrostimulation therapy of the posterior tibial nerve TTNS), and a third group (GIII=Combined therapy).
The tolterodine group received 4 mg of tolterodine daily for 10 weeks, the second group received transcutaneous tibial nerve stimulation. The frequency used was 10 Hz, the pulse width was 200 microseconds and the intensity was adjusted between 10 and 25 mA). The therapy consisted of two 30-minute sessions per week, with a total of 12 sessions; and a third group with combined therapy. Patients were evaluated at weeks 0, 3 and 6, one month and three months after the end of treatment; using a three-day bladder diary, and through validated questionnaires in Spanish. The primary response is observed in urinary frequency, urgency, nocturia and urinary incontinence. The secondary response would depend on the total score of three quality of life questionnaires: OABSS and IIQ-7.

RESULTS: All bladder diary parameters improved significantly in all groups (p<0.05). Similarly, all scores measured through questionnaires (OABSS and IIQ-7) had significant improvement in the three groups (p<0.05). When improvements in symptoms were compared between groups, there was a statistically significantly greater improvement in group III in relation to frequency, nocturia, urgency and urgency urinary incontinence.

There were no significant differences between treatment groups in terms of body mass index, smoking and menopause status, presence of DM, SAH, parity, and menopause. 
The mean and standard deviation of the urinary frequency value of the patients in group I (Tolterodine) was 12.15±3.18; of group II (TTNS) was 10.75±2.04; and group III (Combined Therapy) was 11.9±3.25, p=0.318.
The mean and standard deviation of the nocturia value of the patients in group I (Tolterodine) was 2.4±1.5; of group II (TTNS) was 2.85±1.34; and group III (Combined Therapy) was 2.55±1.53, p=0.178.
The initial percentage and standard deviation of the urinary incontinence value of the patients in group I (Tolterodine) was 15 (75%) ± 3.68; of group II (TTNS) was 18 (90%) ± 4.03 and of group III (Combined therapy) was 20 (100%) ± 5.56, p = 0.147.
The initial percentage of the severity of urinary incontinence of patients in group I (Tolterodine) was 20 (100%); in group II (TTNS) it was 20 (100%) and in group III (Combined Therapy) it was 20 (100%), p=01.0.
The mean and standard deviation of the OABSS questionnaire of the patients in group I (Tolterodine) was 25.2±2.62; of group II (TTNS) was 25.2±2.09; and group III (Combined Therapy) was 25.2±2.19, p=0.931.
The mean and standard deviation of the IIQ-7 questionnaire of the patients in group I (Tolterodine) was 19.8±1.52; of group II (TTNS) was 19.5±1.7; and group III (Combined Therapy) was 19.7±1.12, p=0.683.

Electrostimulation therapy in the posterior tibial nerve with the parameters established in this study is a safe, simple and minimally invasive treatment modality in patients with OAB, and it is concluded that it is useful either alone or in combination with tolterodine, when the treatments front liners fail.
The use of tolterodine, transcutaneous electrostimulation therapy of the posterior tibial nerve in isolation and in combination demonstrated similar results in reducing incontinence episodes and improving quality of life in patients with OAB in a period of 3 months, although the combined therapy is superior than the other three treatment modalities in managing OAB symptoms. These results make combined therapy the best option in terms of safety and effectiveness for the management of OAB refractory to first-line treatment.
The combination therapy was the only one that showed a 100% improvement in the severity of urinary incontinence. The combined therapy is superior to the other two treatment groups in relation to OABSS and IIQ-7 quality of life questionnaires.