Objective: To explore whether combined detrusor and external urethral sphincter botulinum toxin A (BTX-A) injections can decrease leak point pressure (LPP) in patients with incontinence secondary to spinal cord injury (SCI).
Methods: A prospective, single-center, single-blind and randomized controlled trial was conducted from June 2013 to August 2015. SCI patients with urinary incontinence secondary to detrusor overactivity and/or low compliance were investigated. At a 1:1 ratio, patients randomly received 200 U BTX-A intradetrusor plus 100 U BTX-A external urethral sphincter (experimental group) or 200 U BTX-A intradetrusor injections (control group). Patients were evaluated at baseline and week 12 after injection. The primary outcomes included LPP and leak point volume (LPV). Secondary outcomes included maximum urethral closure pressure (MUCP), Incontinence-Specific-Quality-of-Life (I-QoL), urinary incontinence episodes, complete dryness, and voiding volume. Adverse events were recorded.
Results: Eighty-four patients (44 in experimental group, 40 in control group) had completed the trials. There were no significant differences in baseline characteristics (gender, age, duration of SCI, level of neurological injury, AISA scores) between the two groups. There were significant differences between the experimental and control groups at week 12 for the improvement of LPP (−18.54 vs. −10.14 cmH2O, P=0.003), LPV (88.70 vs. 55.32 mL, P=0.037), MUCP (−29.76 vs. −7.56 cmH2O, P=0.003), I-QoL (37.46 vs. 27.64, P=0.004), urinary incontinence(−6.68/d vs. −5.11/d, P=0.014), complete dryness (24 vs. 13, P=0.042) and voiding volume (118.94 vs. 84.96 mL, P=0.033). We observed eight patients (six in the experimental group, two in the control group) with mild transient hematuria for 2–4 days and six patients (two in the experimental group, four in the control group) with bladder discomfort for 6–12 hours.
Conclusions: Combined detrusor and external urethral sphincter BTX-A injections is more effective than single detrusor BTX-A injections for the improvement of LPP, LPV and the quality of life.
