Detrusor sphincter dyssynergia (DSD) causes impaired micturition and high intra-vesical pressure that leads to potentially life-threatening urological complications. Botulinum toxin A (BTX-A) is an inhibitor of acetylcholine release at the neuromuscular junction, which can decrease muscle contractility. It has been used successfully in the treatment of focal dystonia and spasticity of skeletal muscles. This study investigates the effectiveness of BTX-A injection to the external urethral sphincter guided by transrectal ultrasound in the treatment of spinal cord injury (SCI) patients with DSD.

A total of 18 patients with DSD (15 men and 3 women) were caused by SCI. BTX-A (100μ) was injected into external urethral sphincter(EUS) respectively in four sites at 12.3,6.9 o’clock guided by transrectal ultrasound. Clinical effects and urodynamic parameters were compared at baseline and after treatment one month.

The EUS was clearly identified as a neatly hypoechoic area extending from the prostatic apex to the levator ani muscle in men patients, but not in women patients. After treatment, the urinary function and urodynamic parameters is improved significantly compared with the baseline (P<0.05), and at 4 week up to a maximum efficacy. In total, 6 (33.3%) patients had an excellent result and had 5 (27.7%) significant improvement. Relatively poor bladder contractility tended to be more frequent in the unimproved patients. However, the catheter insertion becomes easier in patients with failed treatment. Stress urinary incontinence was reported in 4 patient. There was no other obvious side effects occurred in patients.

Transrectal ultrasound is an effective method to visualize the lower urinary tract and allows for the accurate targeting of the EUS. It is a simple and repeatability method for the treatment of DSD. BTX-A injection to the EUS guided by transrectal ultrasound is an effective method in the treatment of SCI patients with DSD.