ИСТИНА

Hypothesis / aims of study Botulinum Toxin A (BoNT A) injections is a minimally invasive yet effective treatment for patients suffering from overactive bladder resistant to conventional therapy (i.e. behavioral therapy, physiotherapy and oral medication). The procedure can be performed in outpatient setting under local anesthesia, but is then often associated with significant pain and discomfort. The inspiration for the idea came from the neurosurgical use of Ringer’s solution in neurosurgery during neurophysiological monitoring where the electrodes are placed directly on brain cortex. The 2016 article by Dirk Dressler et al. further bolstered our belief, that alterations in environmental pH would affect the threshold of pain perception. Because of its slightly more alkaline pH and mineral composition we thought, that Ringers solution is capable to elevate pain perception threshold while being used as bladder irrigation solution. The objective of current pilot study was to test out the anesthetic capability of Ringer's solution for intradetrusor BoNT A injections. Study design, materials and methods Inclusion/exclusion criteria After excluding patients with diagnosed diabetes mellitus and/or neurologic conditions since they may affect as well as chronic renal disease. 42 patients aged 36-90 y.o. (36-female and 6- male) underwent intradetrusor 100U BoNT A (BOTOX™ Allergan, Irvine. CA 92612) injections for non-neurogenic overactive bladder in time frame from February till December 2020 at the single day/outpatient department of Moscow City Hospital named after S.I. Spasokukotsky. Patients were randomly assigned into control (n=22) and "Ringer's" (n=20) groups. BoNT A in both groups was prepared according to standard 100U BOTOX™ reconstitution and dilution procedure and injected at 10 sites using Laborie cystoscopy injection needle. After the procedure each patient filled out a questionnaire and rated experienced pain and discomfort on a visual analogue scale (VAS), adopted for Russian language (where 0 would be no pain at all and 10 - most extreme pain and discomfort ever experienced). Prior each procedure an informed crescent was obtained. Results In comparison to control group (BoNT A injections performed under Lidocain+Chlorhexidin containing gel (Instillagel, FARCO-PHARMA, GmbH) and 0,9% NaCl irrigating solution), patients in the Ringer's group showed an improvement on VAS by at least 2-3 points (mean score went from 7.09 to 5.15). Those patients (N=4), who underwent repetitive BoNT injections noted that under Ringer's solution pain was more localized momentary and more tolerable in comparison to previous experience. Interpretation of results Current study was not without its numerous limitations. Patients of particularly older age may have altered bladder wall sensation due to neurogenic and/or diabetic tissue alterations. Few of our patients were thoroughly screened previously by neurologist or general practitioner. Two of the patients struggled/were unwilling to fill out VAS score. The study was severely disrupted during 2020 Covid – pandemic since our department was repurposed for treating Covid patients. Conclusion The use of Ringer's solution for bladder irrigation is a feasible way to reduce pain and discomfort for patients undergoing intradetrusor BoNT A injections under local anesthesia for overactive bladder in outpatient setting. Although preliminary results of a current study showed promising results as a proof of concept, the use of Ringer's solution as well as other alternative solutions for cystoscopy irrigation warrant further multicentric studies. Concluding message more widespread use of Ringer's solution as a local anesthetic irrigation media may allow to perform more procedures in outpatient/ambulatory settings, thereby minimizing associated costs, risks and hospital (bed) resources, which tend to be vitally important during current Covid-19 pandemic.