Study design, materials and methods
Pilot, prospective study in which 29 patients diagnosed with Overactive Bladder Syndrome (OBS) refractory to medical treatment were included. Those patients of legal age who had received at least two lines of pharmacological treatment without improvement were included in the study.
The procedure was performed on an outpatient basis in the urology examination room. After preparing the sterile field and placing a local anesthetic gel, a 16 Fr silicone catheter with a positive intraurethral electrode is inserted, the bladder is emptied and two negative electrodes are placed at the skin level. 100 IU botulinum toxin is introduced intravesically along with 100 ml of sterile water. After instillation of the drug, a plug is placed in the urinary catheter and the electrodes are connected to the electroiontophoresis system (Physionizer 30 N2: force 25 mA, maximum amplitude 50 microA/sec). The instillation was performed for 30 minutes with subsequent bladder emptying.
The following parameters were evaluated pre-instillation and 6 months after instillation: maximum bladder capacity (MBC) in the urodynamic study (UDS), 3-day voiding diary (VD) and CACV voiding symptoms questionnaire. Finally, complications after installation were recorded.
All patients in this study were previously offered intravesical injection and rejected it because of the side effects related to the bladder puncture. Electroiontophoresis was then proposed as an alternative and they accepted the technique.
Results
Statistically significant improvements were observed 3 months after treatment in the CAVC questionnaire, the 3-day voiding diary and the urodynamic parameters presenting: increase in MBC in the UDS (164.4ml vs 239.9ml) p<0.05, improvement in parameters of VD given by decrease in day-time frecuency (8.31 vs 6.66), decrease in episodes of urinary urgency (2.52 vs 1.54) and increase in mean voiding volume (143.97ml vs 198.38ml) p<0.05. Furthermore, we evidenced a decrease in night-time frequency (2.59 vs 2.07), although this difference was not statistically significant. Finally, we found a decrease in the CACV questionnaire score (10.2 vs 6.9) p<0.05.
Of the total sample, the parameters that showed the highest percentage of improvement were: the CACV in which 82.7% of the patients reported improvement, followed by the decrease in the Emergency episodes referred to in 68.97% of the cases. In addition, we also found a high percentage of patients with improvement in other parameters such as: day-time frecuency (62%) and night-time frequency (58.6%).
After one dose of treatment we observed a statistically significant decrease in the result of the CACV questionnaire (10.2 vs 6.9) being (T test p<0.05) and an increase in maximum bladder capacity (164.4 vs 239.9) (p<0.05). With respect to the other parameters, we evidenced a statistically significant decrease in day-time frecuency (8.31 vs 6.66), urgency (2.52 vs 1.54) and lastly an increase in mean voiding volume (143.97 vs 198.38) with (T test p<0.05). Finally, night-time frequency was decreased by (2.59 vs 2.07), although this difference was not significant.
Only 2 patients presented complications, all of them being Clavien Dindo grade I. When evaluating the degree of satisfaction with the technique, 93.1% of patients reported a high degree of satisfaction with it, 72.4% would perform the procedure again, including 31% of patients who had been previously treated by botulinum toxin injection. Patients who indicated that they would not repeat the procedure coincide with those who did not achieve clear improvement in CACV.
Interpretation of results
In our study, intravesical instillation of botulinum toxin type A through the use of electroiontophoresis is an effective treatment, which presents improvement in urodynamic parameters and voiding diary in patients with OBS refractory to medical treatment. The treatment is well tolerated and has a low complication rate.