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Sir

Botulinum toxin (BTX) is about to become a standard therapy for hyperactive detrusor and sphincter dysfunction of different origins. Sphincter injections have been used in urology mainly for treating neurogenic detrusor sphincter dyssynergia [1], but detrusor injections have been increasingly dominant in this condition for ª 5 years [2]. Most users give 20–40 injections of BTX with a long needle through a rigid cystoscope. Harper et al.[3] described a minimally invasive technique in which a standard flexible cystoscope is used to spread the toxin over the wall of the bladder. As noted by them, some urologists still spare the trigone to avoid the theoretical risk of iatrogenic VUR; others include the trigone without this complication [4].

It can be difficult to see where injections have been given and which areas have been omitted. That might pose a serious problem when the injection technique described by Harper et al. is used, because orientation through a flexible cystoscope is often more confusing than orientation through a rigid cystoscope. For those who are starting with detrusor injections, we recommend using indigo carmine to mark the sites where BTX has already been applied. For demonstration purposes, we use the common dilution of 200–300 units of BTX-A in 16 mL of normal saline and add 4 mL of indigo carmine (Indigo Carmine Solution Ampoules, Paesel + Lorei, Germany) to bring the total volume to 20 mL. Each injection is ª 0.5 mL. We prefer to use a systematic checkered pattern, which is easy with a rigid cystoscope. Indigo carmine makes it easy to see where BTX has already been administered (Fig. 1).

image

Figure 1. The blue spots at the 6, 8 and 12 o’clock positions are clearly visible, where BTX has already been injected.

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Using the dye shows how widely the toxin spreads immediately at the submucosal site (Fig. 1). Furthermore, it can be shown that almost no toxin flows back from the suture tracts into the bladder when it is full. In contrast, when the bladder is only half-full, there seems to be backflow into the bladder. The dye technique is not necessary in general, but for teaching or demonstration purposes, and for the first few injections, it is useful, especially when the flexible cystoscope is used.

  • 1
    Dykstra DD, Sidi AA, Scott AB, Pagel JM, Goldish GD. Effects of botulinum A toxin on detrusor-sphincter dyssynergia in spinal cord injury patients. J Urol 1988; 139: 91922
  • 2
    Reitz A, Stohrer M, Kramer G et al. European experience of 200 cases treated with botulinum-A toxin injections into the detrusor muscle for urinary incontinence due to neurogenic detrusor overactivity. Eur Urol 2004; 45: 5105
  • 3
    Harper M, Popat RB, Dasgupta R, Fowler CJ, Dasgupta P. A minimally invasive technique for outpatient local anaesthetic administration of intradetrusor botulinum toxin in intractable detrusor overactivity. BJU Int 2003; 92: 3256
  • 4
    Chancellor M, O'Leary M, Erickson J et al. Successful use of bladder botulinum toxin injection to treat refractory overactive bladder. J Urol 2003; 169 (Suppl 4): 351