Hypothesis / aims of study
Detrusor overactivity (DO) may be present in men after SUI surgery, representing a challenging scenario. To our knowledge, few studies have addressed the results of intradetrusor onabotulinumtoxin A injection (BoNT-A) in male patients and, more specifically, in patients with DO after SUI surgery. Our aim was to assess treatment response, complications, and rate of continuation on treatment after intradetrusor onabotulinumtoxin A injection (BoNT-A) in these patients.
Study design, materials and methods
Retrospective analysis of men with prior SUI surgery treated with 100 UI of BoNT-A because of DO since 2010 in our department. Injection was performed with a 5-Fr 4-mm depth needle via a rigid cystoscope in those patients with no history of artificial urinary sphincter (AUS) placement. In patients with AUS, the same needle was inserted via a flexible cystoscope after AUS cuff deflation and deactivation, reactivating the device 12 h after the procedure.
Follow-up included a urodynamic test after 3 months. Treatment response was assessed with a treatment benefit scale (TBS): 1, greatly improved; 2, improved; 3, not changed; 4, worsened after treatment (1-2: response to treatment; 3-4: non-response to treatment). Complications were classified according to the Clavien-Dindo (CD) classification. Treatment continuation was considered present if, at the last visit, patients had received BoNT-A within the preceding 12 months. Reasons for discontinuation were also collected. The pre- and postoperative urodynamic variables were compared using the Student’s t test for paired samples, the paired-sample Wilcoxon test, or the McNemar when appropriate. Ethical approval and written patient consent were obtained in accordance with our institution’s policy.
Results
18 men were included, median age 71.1 (59.1–83.5) years. 15 (83.3%) patients had history of prior prostatectomy and 3 (16.7%) patients of prior TURP. 9 (50%) patients had undergone an AUS (AMS 800®) placement, 7 (38.9%) a Remeex® sling, and 2 (11.1%) an AdVanceXP® sling. 12 (66.7%) patients reported response to treatment. While all patients presented with DO before BoNT-A injection, DO was present in 8 (53.3%) patients after treatment (p0.016).
Two (11.1%) postoperative complications occurred (urinary retention requiring CIC, CD2). No complications related to the previous SUI surgery were detected. 15 (83.3%) patients had a follow-up >12 months [median follow-up 57 (15–89) months] and all of them had discontinued treatment at the end of follow-up. Reasons for discontinuation were lack of therapeutic benefit in 4 (26.7%), complications in 1 (6.7%), lack of severe symptoms in 3 (20%), and unwillingness to repeat treatment despite treatment response in 7(46.7%) patients.
Interpretation of results
According to our results, most male patients with DO and prior history of SUI surgery respond to BoNT-A injection treatment. Moreover, it seems a safe treatment as complications were infrequent and mild.
Recurrent SUI due to a loss of fluid from the pressure-regulating balloon has been reported in a small series of pediatric patients with neurogenic DO with a previously implanted AUS who underwent an intradetrusor BoNT-A injection [1]. Although no complications related to the previous SUI surgery, such as urethral erosion or AUS mechanical failure, occurred in our series, we strongly believe that transurethral instrumentation through an AUS cuff must be conducted with extreme caution and with the minimum gauge possible in order to avoid urethral damage and further cuff erosion, as well as avoiding injection of BoNT-A into the bladder wall against which the AUS balloon leans.
Despite BoNT-A injection can be a treatment choice in male patients with prior SUI surgery, all patients included in our study discontinued treatment during follow-up. However, it has to be mentioned that efficacy issues were a minor reason for treatment discontinuation.