Pharmacotherapy in Pediatric Neurogenic Bladder Intravesical Botulinum Toxin Type A

Success Rate and Predicting Factors for Repeated High-Dose Intradetrusor Dysport Injections in Children With Neurogenic Bladder: A Retrospective Study

OBJECTIVES

Evaluating the effectiveness and safety of repeated high-dose intradetrusor abobotulinumtoxin A (Dysport®) injections for the treatment of pediatric neurogenic bladders refractory to medications.

DESIGN

Retrospective interventional study.

PARTICIPANTS

The cohort included 37 children (22 boys and 15 girls) of median age 9.2 years. Inclusion criteria were diagnosis of neurogenic bladder and failure to respond to medical treatment. Exclusion criteria were augmented bladder, insufficient data, and interval of > 11 months between video-urodynamic study and Dysport injection.

INTERVENTIONS

All participants were treated with an intra-detrusor injection of Dysport 30 IU/kg (up to 1000 IU) under general anesthesia. Repeated (second and third) injections were scheduled (6-12 months) in patients who demonstrated an improvement in cystometric parameters. All participants underwent video urodynamic testing before onset of treatment and 4-5 months after subsequent injection.

MAIN OUTCOME MEASURES

Success of treatment was defined as a decrease in end filling pressure (EFP) to < 40 cm H2O and/or a 20% increase in maximal cystometric capacity (MCC). These parameters along with initial bladder features were evaluated for ability to predict treatment success.

RESULTS

No side effects of Dysport were observed or reported. The overall success rate was 62%. MCC increased by a median of 30% (IQR 200-300, p < 0.001), 37% (IQR 197-310, p = 0.001) and 45% (IQR 245-300, p = 0.025) after the first, second and third injections, respectively. Median EFP decreased from 45 cm H2O to 34 cm H2O (IQR 20-45, p = 0.029), 23 cm H2O (IQR 20-37, p = 0.004), and 20 cm H2O (IQR 12-32, p = 0.049) after the first, second, and third injections, respectively. No predicting factor of success of treatment were found; However, three of five cases of "end stage" bladder showed improvement.

CONCLUSIONS

High-dose Dysport injection is safe and effective for the treatment of neurogenic bladder. Studies with larger cohort and a control group would further elucidate which bladders would benefit most. At present, we recommend treating also bladders with "end stage" features with botulinum toxin before considering augmentation.

Indications for Augmentation Cystoplasty in the Era of OnabotulinumtoxinA

Overactive bladder (OAB) with or without a neurogenic etiology that is refractory to conventional first-, second-, and third-line therapies is a challenging condition that typically leaves the physician and the patient with few options. Historically, treatment for patients who did not respond to any of the few pharmacologic choices focused on more invasive surgical options--specifically, augmentation cystoplasty (AC). In 2011 and 2013, the Food and Drug Administration (FDA) approved intradetrusor injection of onabotulinumtoxinA for the treatment of neurogenic detrusor overactivity (NDO) and idiopathic detrusor overactivity (IDO), respectively. Since then, a dramatic decline in the use of AC has called into question its utility in the treatment algorithm of this difficult patient population. The purpose of this paper is to review the current body of literature in order to outline the circumstances in which AC is still a relevant therapeutic option.

Preclinical assessment of potential interactions between botulinum toxin and neuromodulation for bladder micturition reflex

BACKGROUND

While botulinum toxin A (BoNT-A) has become a more commonly used second-line treatment for patients with detrusor overactivity, it remains unknown whether the impacts of this therapy may persist to influence other therapies such as sacral neuromodulation. In this preclinical study we have evaluated urodynamic functions to intradetrusor injection of BoNT-A and the bladder inhibitory effects of spinal nerve stimulation (SNS) following BoNT-A treatment.

METHODS

Female rats were anesthetized with 3 % isoflurane. BoNT-A (2 units, 0.2 ml) or saline were injected into the detrusor. Rats then were housed for 2 days to 1 month before neuromodulation study. Monopolar electrodes were placed under each of the L6 spinal nerve bilaterally under urethane anesthesia. A bladder cannula was inserted via the urethra for saline infusion and intravesical pressure recording.

RESULTS

Intradetrusor injection of BoNT-A for 1-2 weeks or 1 month significantly increased bladder capacity compared with saline injection (p < 0.05, two-way ANOVA). Following BoNT-A, SNS attenuated the frequency of bladder contractions, either eliminating bladder contractions or reducing the contraction frequency during electrical stimulation. Inhibition of the contraction frequency by SNS following BoNT-A treated rats was not different from that measured following saline injection.

CONCLUSIONS

BoNT-A increased the bladder capacity, but compensating for additional saline infusion to the enlarged urinary bladder in BoNT-A pretreated rats, the bladder contractions induced by bladder filling were attenuated by SNS. BoNT-A did not alter the ability of SNS to inhibit bladder contraction following intradetrusor injection of BoNT-A for 2 days, 1-2 weeks or 1 month. These results support further pre-clinical and clinical studies to evaluate potential interactions or combination therapy with neuromodulation and intradetrusor BoNT-A therapeutic approaches.