Purpose: We compared the effectiveness of detrusor, suburothelial and bladder base injections of botulinum toxin type A in patients with idiopathic detrusor overactivity.
Materials and methods: A total of 45 patients with idiopathic detrusor overactivity refractory to antimuscarinic therapy were randomly allocated to receive 100 U botulinum toxin type A injected into detrusor, suburothelial and bladder base. Videourodynamic studies were performed at baseline and 3 months after treatment. Data collected included symptom score, urgency and incontinence episodes, and urgency severity score. A general satisfaction rating was also assessed as excellent, moderately improved, mildly improved or stationary. A moderately improved or excellent result was defined as successful treatment.
Results: A total of 15 patients were allocated to each treatment group. A successful result at 3 months was achieved in 14 (93%) patients with detrusor, 12 (80%) with suburothelial and 10 (67%) with bladder base injection. The success rate in the detrusor, suburothelial and bladder base injection groups decreased with time to 67%, 47% and 13% by 6 months, and 20%, 20% and 6.7% at 9 months, respectively (p = 0.0253). Vesicoureteral reflux was not found in any patient after botulinum toxin type A injection. Urgency severity scores improved significantly in all groups after treatment. At 3 months after treatment significant increases in cystometric capacity and post-void residual compared to baseline were found in the detrusor and suburothelial but not in the bladder base group.
Conclusions: Intravesical injection of 100 U botulinum toxin type A by all 3 methods had a therapeutic effect on idiopathic detrusor overactivity. Bladder base botulinum toxin type A injection relieved urgency sensation but did not increase bladder capacity.