Botulinum toxin injections (Botox® bladder)

Indications

Bladder botulinum toxin injection is considered in the following cases:

• Overactive bladder refractory to or intolerant of first-line treatments (anticholinergics, beta-3 agonists).
  
• Presence of symptoms including at least:
  three episodes of urinary incontinence by urgency over 3 days
  – urinary frequency ≥ 8 micturitions per day
  
• Patient acceptance of the risk of transient urinary retention and the possibility ofself-catheterization if necessary.
  
• Sterile urine at the time of injection (treated urinary tract infection or absence of infection).
  

Note: in France, Botox’s marketing authorization mainly concerns idiopathic overactive bladder, and its use in this indication must comply with best practice recommendations.

Surgical technique

Here’s how a typical botulinum toxin injection is performed:

1️⃣ Pre-injection preparation

• Cytobacteriological control of urine to ensure absence of infection.
  
• Urodynamic workup (in many cases) to confirm diagnosis and guide dosage.
  
• Information, consent, assessment of ability to perform self-catheterization if necessary.
  
• Local anesthesia (urethral or bladder lidocaine instillation), sometimes sedation or anesthesia depending on the context.
  

2️⃣ Injections

• Endoscopically (cystoscopy): a fine needle injects the toxin into the bladder muscle (detrusor) at 10 to 20 points distributed throughout the bladder wall, avoiding the ureteral meatus.
  
• Micro-volumes (0.5 to 1 mL per injection, containing several units of toxin) are used to achieve the desired dose.
  
• Bladder filling is controlled to avoid excessive wall distension.
  
• It is not necessary to leave a bladder catheter except in cases of severe hematuria.
  

3️⃣ Duration and hospitalization

• The procedure is relatively rapid, often performed on an outpatient or short-stay basis.
  
• The patient is monitored until miction resumes.