Does reducing the number of intradetrusor botulinum toxin type A injection sites affect efficacy and safety in patients with spinal cord injury?

Objective To investigate the clinical effect and safety of different numbers of botulinum toxin type A (BTX-A) bladder injections in the treatment of neurogenic detrusor overactivity (NDO). Design A single-blind randomized control trial. Setting A single spinal cord injury (SCI) rehabilitation center in China. Participants A total of 44 patients with spinal cord injury and neurogenic detrusor overactivity who underwent intradetrusor injection of 200 U BTX-A were enrolled. The cohort included 34 men and 10 women. Interventions They were randomly divided into two groups of 30 vs. 20 sites of injection with 200 U BTX-A. Outcome measures Urodynamic parameters such as maximum detrusor pressure at first DO (PdetmaxDO), volume at the first involuntary detrusor contraction, were measured at baseline and week 12 after injection. Mean urine volume per catheterization(V-CIC), scores of the Incontinence Specific Quality of Life Instrument (I-QoL) were also recorded before and after treatment. Results At the endpoint, both the urodynamic parameters and volume of catheterization improved significantly, without a significant difference between the two groups. Mean decreases in the maximum detrusor pressure were -31.95 and -25.77 cmH2O in the 20- and 30-injection groups. The increases in volume at the first involuntary detrusor contraction from baseline were +130.86 and +122.73 ml, respectively. There was no significant difference in the change in incontinence severity or I-QoL improvement between the two groups. The urinary incontinence episodes per week decreased from 48.41 ± 6.71-17.50 ± 16.17 and from 53.27 ± 11.33-22.91 ± 18.94 in the 20- and 30-injection groups, respectively (all P < 0.001). There were eight and seven patients with complete dryness after treatment. Conclusions When the total dose of 200 U was maintained, reducing the number of injection sites from 30 to 20 had a similar therapeutic effect in NDO without compromising safety. Clinically, this approach may be advantageous in terms of reducing the operating time and improving patient comfort.