Botulinum toxin type A injections into the urethral sphincter for idiopathic chronic non-obstructive urinary retention

Botulinum toxin type A injections into the urethral sphincter for idiopathic chronic non-obstructive urinary retention

NICE state that:

• for people with idiopathic chronic non-obstructive urinary retention caused by external urethral sphincter dysfunction (also known as Fowler's syndrome in younger women and people with female anatomy, primary disorder of urethral sphincter relaxation or high-tone non-relaxing urethral sphincter), botulinum toxin type A injections into the urethral sphincter should only be used with special arrangements for clinical governance, consent, and audit or research
• the NICE committee noted:
  • "..External urethral sphincter dysfunction is rare, and evidence from observational studies suggests that the procedure may improve symptoms. But there are uncertainties about how well it works and how safe it is in the long term. So, it should only be used with special arrangements for external urethral dysfunction.."

The effect of botulinum toxin type A on urethral striated muscle is thought to block the presynaptic release of acetylcholine in the neuromuscular junction and subsequently achieve a chemical sphincterotomy, which is believed to relieve the rethral sphincter dysfunction (USD) and improve voiding dysfunction (VD) (2)

• voiding dysfunction (VD) leads to slow or incomplete micturition in both males and females
  • condition can be either
    • neurogenic
      • for example, detrusor sphincter dyssynergia (DSD)
    • or non-neurogenic
      • dysfunctional voiding (DV), Fowler's syndrome (FS), and poor relaxation of the external urethral sphincter (PRES) during voiding comprise the non-neurogenic causes

Reference:

• NICE (June 2023). Botulinum toxin type A injections into the urethral sphincter for idiopathic chronic non-obstructive urinary retention
• Kao YL, Huang KH, Kuo HC, Ou YC. The Therapeutic Effects and Pathophysiology of Botulinum Toxin A on Voiding Dysfunction Due to Urethral Sphincter Dysfunction. Toxins (Basel). 2019 Dec 13;11(12):728. doi: 10.3390/toxins11120728. PMID: 31847090; PMCID: PMC6950422.