Purpose: We evaluated the efficacy of botulinum-A toxin injections into the detrusor muscle in patients with spinal cord injury, detrusor hyperreflexia and urge incontinence resistant to anticholinergic drugs. The purpose of treatment was to suppress incontinence episodes and increase functional bladder capacity.

Materials and methods: Included in our prospective nonrandomized study done at 2 clinics were 31 patients with traumatic spinal cord injury who emptied the bladder by intermittent self-catheterization. These patients had severe detrusor hyperreflexia and incontinence despite a high dose of anticholinergic medication. Pretreatment evaluation included a clinical examination and complete urodynamic investigation. Under cystoscopic control a total of 200 to 300 units of botulinum-A toxin were injected into the detrusor muscle at 20 to 30 sites (10 units per ml. per site), sparing the trigone. Clinical and urodynamic followup was planned for 6, 16 and 36 weeks after treatment. Patients were asked to decrease their intake of anticholinergic drugs during week 1 after treatment.

Results: Of the 21 patients 19 underwent a complete examination 6 weeks after the botulinum-A toxin injections, and 11 at 16 and 36 weeks. At the 6-week followup complete continence was restored in 17 of 19 cases in which anticholinergic medication was markedly decreased or withdrawn. Less satisfactory results in 2 cases were associated with an insufficient dose of 200 units botulinum-A toxin. After the injections overall mean reflex volume and mean maximum cystometric bladder capacity plus or minus standard deviation significantly increased from 215.8 +/- 90.4 ml. to 415.7 +/- 211.1 (p <0.016) and 296.3 +/- 145.2 to 480.5 +/- 134.1 (p <0.016), respectively. There was also a significant decrease after treatment in mean maximum detrusor voiding pressure from 65.6 +/- 29.2 cm. water to 35 +/- 32. 1 (p <0.016). Mean post-void residual urine volume catheterized at the end of the urodynamic examination increased significantly from a mean of 261.8 +/- 241.3 ml. to 490.5 +/- 204.8 (p <0.016). Moreover, autonomic dysreflexia associated with bladder emptying that manifested as a hypertensive crisis during voiding disappeared after treatment in the 3 patients with tetraplegia. Satisfaction was high in all successfully treated patients and no side effects were observed. Ongoing improvement in urodynamic parameters and incontinence was already present in all patients reevaluated at 16 and 36 weeks.

Conclusions: Botulinum-A toxin injections into the detrusor seem to be a safe and valuable therapeutic option in spinal cord injured patients with incontinence resistant to anticholinergic medication who perform clean intermittent self-catheterization. Successfully treated patients become continent again and may withdraw from or markedly decrease anticholinergic drug intake. A dose of 300 units botulinum-A toxin seems to be needed to counteract an overactive detrusor. The duration of bladder paresis induced by the toxin is at least 9 months, when repeat injections are required.