Causes of failed urethral botulinum toxin A treatment for emptying failure.
OBJECTIVE
Urethral injection of botulinum toxin A (BTX-A) can reduce urethral resistance in patients with voiding dysfunction. However, some patients do not benefit from this treatment. It is essential to identify the causes for these failed procedures.


METHODS
A total of 200 patients receiving urethral BTX-A injections for voiding dysfunction refractory to conventional medication during a 5-year period were included in this study. The patients received 50 or 100 U of BTX-A injected into the urethral sphincter. Treatment was considered successful when patients were subjectively satisfied with the outcome and (a) patients with chronic urinary retention resumed spontaneous voiding, (b) patients with a large postvoid residual volume had a reduction in postvoid residual of more than 50%, (c) patients voided with a lower detrusor pressure or lower abdominal pressure to urinate adequately. The therapeutic results and causes of failed treatment were retrospectively analyzed.


RESULTS
The overall success rate was 88.5% (177 patients), including 47.5% (95 patients) with an excellent result and 41% (82 patients) with an improved result. The causes of failed treatment in 23 patients were detrusor underactivity with very low abdominal straining pressure in 7, a tight urethral sphincter in 7, bladder neck obstruction in 7, and psychological inhibition of voiding in 2. Transurethral incision of the bladder neck was performed in 7 patients, and all had an improved result.


CONCLUSIONS
BTX-A urethral treatment failed in 11.5% of patients with voiding dysfunction refractory to medical treatment after one session. Careful investigation of the underlying causes of failed treatment is mandatory to achieve a satisfactory outcome.
Liao
Yung-Ming
YM
Department of Urology, Buddhist Tzu Chi General Hospital and Buddhist Tzu Chi University, Hualien, Taiwan.
Kuo
Hann-Chorng
HC
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D002648:Child; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D008875:Middle Aged; D017211:Treatment Failure; D014521:Urethra; D016055:Urinary Retention / Q000209:etiology / Q000628:therapy*
D019274:Botulinum Toxins, Type A