[Detrusor-sphincter dyssynergia and botulinum toxin]

Botulinum toxin (BT) injection into the external urethral sphincter is a promising therapy for neurogenic voiding disorders due to detrusor-sphincter dyssynergia (DSD). However the optimal treatment protocol remains unclear.

A PubMed reference search and manual bibliography review were performed, along with a search in the Annales de réadaptation et de médecine physique and in the reports of the International French-language Society of Urodynamics and the International Continence Society, which allowed us to select twelve pertinent articles with PubMed, two articles from the Annales and two conference reports. Our analysis gave special emphasis to assessment criteria, application, dosage and BT injection technique.

Used for the first time in 1988 in spinal cord injury patients to reduce outflow obstruction due to DSD, BT injections have been shown to be a valuable alternative management of bladder dysfunction with DSD. They have been proposed in neurological patients unable to perform self-catheterisation, after drug failure and before surgery. Parameters for results assessment are mostly clinical (increased free interval between voiding, decreased post-void residual urine volumes), urodynamic (improvement in bladder emptying, increase in functional bladder capacity and decrease in urethral pressure) and electromyographic (denervation of striated urethral sphincter). The literature data regarding type of BT, dosage and protocol vary widely. Duration of action is from 2 to 12 months. Both transurethral and transperineal injections monitored by EMG are equally effective in improving detrusor-sphincter dyssynergia.

With few side effects and satisfactory medium-term results, BT should be recommended as a component of DSD therapies. We propose a practical method for BT use.