Objectives: To study the effect of botulinum toxin A (BoNTA) injections into the detrusor muscle on the incidence of symptomatic urinary infections in patients with neurogenic detrusor overactivity.
Methods: Between February 2004 and June 2005, 30 patients (18 men, 12 women), mean age 39.4+/-12.1 yr, with neurogenic detrusor overactivity received an injection of 300 U Botox (Allergan Inc., Irvine, CA, USA) into the detrusor. Fifteen patients had multiple sclerosis, 14 had spinal cord injury, and 1 had myelitis. Twenty-two patients had urinary incontinence. Patients were either resistant to anticholinergic medications, had discontinued treatment because of adverse effects, or had contraindications to anticholinergic drugs. Before and 6 wk after injection, each patient kept a bladder diary and underwent urodynamic investigation, retrograde and voiding cystourethrography, and urine culture. All symptomatic urinary infections (pyelonephritis, orchitis, prostatitis) occurring in the 6 mo before and the 6 mo after injection were recorded.
Results: Before injection, the mean number of symptomatic urinary infections over 6 mo was 1.75+/-1.87. After injection, the mean was 0.2+/-0.41 (p=0.003), and only 3 patients presented symptomatic urinary infections. These patients were those who showed less improvement in their urodynamic parameters after injection (volume of the first uninhibited contraction, maximum bladder pressure, and maximum cystometric capacity, respectively; p=0.0037, p=0.0002, p=0.0027, ANOVA).
Conclusions: BoNTA injections into the detrusor muscle significantly decreased the incidence of symptomatic urinary infections. This effect seems to be related to improvement in urodynamic parameters, reflecting improved reservoir capacity at low pressure.