Evaluation of the effect of 100U of Onabotulinum toxin A on detrusor contractility in women with idiopathic OAB: A multicentre prospective study

Abstract

Aims: Intradetrusor injection of Onabotulinum Toxin A (BTX-A) is a thirdline treatment for overactive bladder (OAB). Voiding dysfunction and the need for intermittent catheterization are potential complications, consequent to bladder contractility (BC) decrement. Primary aim: to evaluate BC variation after BTX-A detrusor injection in women with idiopathic OAB. Methods: A prospective multi-institutional observational study was conducted.Medical history, bladder diary, 24-h pad test, and invasive urodynamic parameters were recorded before and 4-6 weeks after BTX-A 100U administration. BC was measured as Modified Projected Isovolumetric Pressure (PIP1), that is, maximum flow rate (Qmax) + detrusor pressure at Qmax (PdetQmax). Continuous variables were expressed as median and interquartile range. We compared continuous variables using Wilcoxon test and proportions between two times with Fisher exact test. Results: No changes in PIP1 were observed (p > 0.05) in 45 women enrolled between January 2018 and September 2019. Median age was 54.6 years. At baseline, 91.1% had urge urinary incontinence, with 4.9 ± 2.6 daily pads used and a 24-h pad test of 205.4 ± 70.8 g. Baseline detrusor contractility was normal in all the patients.Postoperatively, an improvement in the 24-h pad test (p < 0.01), daily voids (p < 0.01), and nocturia (p < 0.01) occurred. Urodynamics pointed out a significant reduction of detrusor overactivity rate (p < 0.01) and an increase of median maximum cystometric capacity (p < 0.01). No difference was observed in median Qmax (p > 0.05), PdetQmax (p > 0.05), and PVR (p > 0.05). No patient needed postoperative catheterization.

Re: Can we say that detrusor contractility didn't change in: “Evaluation“evaluation of the effect of 100 U of onabotulinum toxin A on detrusor contractility in women with idiopathic OAB: A multicentre prospective study”?

“…8 PIP1 did not show any statistically significant variation after botulinum toxin injection (42 cmH2O ranging from 38.3 to 48 before treatment; 42 cmH2O ranging from 35 to 47.1 after treatment), which led us to conclude that 100 U of BTX-A cannot influence bladder contractility while maintaining the therapeutic effects on symptom relief and bladder storage function. 1 We agree that PIP1 has some limitations too. One of them is ignoring the contribution of abdominal pushing during micturition.…”

“…The median PIP1 of the cohort of patients enrolled was 42 cmH2O (interquartile range: 38.3-48 cmH2O), instead of 29 cmH2O. 1 This feature is fundamental, as we treated women with normocontractile detrusors. PIP1 lower than 50 cmH2O would mean administrating BTX-A to bladders with reduced contractility.…”

Clinical Application of Botulinum Neurotoxin in Lower-Urinary-Tract Diseases and Dysfunctions: Where Are We Now and What More Can We Do?

“…In women with OAB, a significant reduction in the DO rate and an increase in the median maximum cystometric capacity were noted after Botox injection for idiopathic DO. The maximum flow rate (Qmax), detrusor pressure (Pdet), and PVR all showed no significant change, and no patient required catheterization after Botox injection [ 19 ].…”

“…Current application of botulinum toxin A on lower-urinary-tract diseases or dysfunctions. ,[7][8][9][10][11][12]15,16,18,19,33,[35][36][37][38] …”

Can we say that detrusor contractility did not change in: “Evaluation of the effect of 100 U of Onabotulinum toxin A on detrusor contractility in women with idiopathic OAB: A multicentre prospective study. De Rienzo G, Minafra P, Iliano E et al. Neurourol Urodyn. 2021 Oct 19. doi: 10.1002/nau.24820”

“…The article "Evaluation of the effect of 100 U of Onabotulinum toxin A on detrusor contractility in women with idiopathic OAB: A multicentre prospective study" by De Rienzo et al 1 showed in a very good way that females older than 18 years (with a mean age of 54.6 years), with projected isovolumetric pressure 1 (PIP1) ≥29 cmH 2 O and postvoid residual volume less than 100 ml, with overactive bladder that did not respond to first-line treatments, responded well to intradetrusor injection of 100U of Onabotulinum toxin A (BTX-A), without causing voiding dysfunction. Although this conclusion is correct, we would like to make a theoretical analysis of why we think that it is probably not possible to say that "contractility was the only parameter that resulted unchanged after BTX-A injection".…”