The effect of botulinum toxin injection to the external urethral sphincter on detrusor wall thickness in patients with detrusor-sphincter dyssynergia

Abstract

Objective To evaluate the effect of injecting botulinum toxin A (BTX-A) to the external urethral sphincter on detrusor wall thickness (DWT) and the bladder function of spinal cord injury patients with detrusor-sphincter dyssynergia (DSD). Methods Twenty-one adult patients with DSD due to spinal cord injury were recruited. A single 100 IU dose of botulinum toxin A was injected into their external urethral sphincters via an ultrasound-guided transperineal route. DWT, detrusor leak-point pressure (DLPP), post-void residual volume (PRV) and maximum bladder capacity(MBC) were assessed by urodynamic examination and ultrasound evaluation before and 4 and 8 weeks after the injection. Results Four weeks later a significant decrease in PRV was observed, but no significant difference in DWT, DLPP or MBC. After eight weeks the mean DWT value had decreased by 17%, a significant reduction. There were also significant improvements in DLPP, PRV and MBC at eight weeks compared with the of baseline values. Conclusions BTX-A injection to the external urethral sphincter can reduce DWT and improve bladder function in spinal cord injury patients with DSD. Key words: Botulinum toxin A; Detrusor wall thickness; Spinal cord injury; Detrusor-sphincter dyssynergia