Botulinum Toxin A Injection for Autonomic Dysreflexia—Detrusor Injection or Urethral Sphincter Injection?

Spinal cord injuries (SCI) have a profound impact on autonomic systems, sometimes resulting in multi-organ dysfunction, including of the neurogenic bladder. Autonomic dysreflexia (AD) is commonly seen in patients with SCI above T6 when the injured cord develops a deregulated sympathetic reflex, which can be induced by bladder sensation and can cause hypertensive crisis. While intravesical injection of botulinum toxin A (Botox) is a standard therapy for neurogenic detrusor overactivity, the role of Botox for AD has rarely been described. This study reviewed the medical records of SCI patients who reported AD and received either detrusor or urethral sphincter injection with Botox. The primary endpoint is the subjective improvement of AD. The secondary endpoint is a change in videourodynamic parameters before and after Botox injection. A total of 200 patients were enrolled for analysis. There were 125 (62.5%) patients in the detrusor injection group, and 75 (37.5%) in the urethral sphincter injection group. There were 79 (63.2%) patients in the detrusor injection group and 43 (57.3%) in the urethral sphincter injection group reporting moderate or marked improvement. Detrusor injection leads to a greater improvement in AD, probably because of decreased detrusor pressure and increased compliance after Botox injection. Urethral sphincter injection appears to have a modest effect on AD, despite general improvements in the voiding parameters of videourodynamic study.