Hypothesis / aims of study
Voiding dysfunction (VD) in females is a common condition with different underlying causes and limited treatment options. The aim of this study was to examine the functional outcomes of Botulinum toxin A (BTX-A) injection into the external urethral sphincter (EUS) for the patients with high tone non-relaxing sphincter (HTNRS), Detrusor underactivity (DU), or detrusor acontractility (DA) as the underlying cause of VD
Study design, materials and methods
Material and Methods: A retrospective analysis of a prospectively maintained database was performed assessing all 34 women of mean age 37.6(18-72) years with HTNRS (maximal urethral closure pressure (MUCP) > 92 – age in years), DU or DA receiving their first EUS Botox A injection between Jan 2015 and Nov 2019. All were evaluated with pre-operative videourodynamics(VUDS) and urethral pressure profilometry(UPP) and all received 100U Botox A. Postoperatively, all patients were assessed with maximum free flow(QMax), post-void residual (PVR), and PGI-I (Patient global impression of improvement) Scale measurement at 3 months. The Median follow-up was 18 months.
Results
We identified 34 female patients with a mean age of 37.5+/-15 years (Range 18- 72 years), who received their first treatment during the study period with a median follow-up of 18months. More than 50% of patients had a history of prior surgical intervention and 28 (80%) patients were catheter dependent. The mean MUCP was 97.1+/- 22 cm of water.
Outcomes are detailed in the table. On multivariate analysis patients with high pre-operative MUCP (> 100 cmH2O) were more likely to have improved Q Max (P= 0.0054), reduction in the need to CISC (P= 0.047), and reduction in PVR (P= 0.006). However,
MUCP value cannot predict the likelihood of subjective improvement (p-value= 0.11).
The mean duration of response was 4 months. 44% of patients requested a repeat injection. The main reasons cited for discontinuation of treatment were the short duration of effect and the need for repeat treatments. On the 5 point PGI-I score, 70% of patients reported improvement. Two patients had transient stress urinary incontinence and there were no significant adverse events.
Interpretation of results
- Onabotulinum ToxinA injection improved urine flow and post void residual as well as reducing the need of self catheterization.
- 70% of patients had some improvement in their symptoms post operatively as reported on PGI-I Scale
- 44% of patients requested for repeat injection but the long term attrition rate is high