Predictors of outcome for urethral injection of botulinum toxin to treat detrusor sphincter dyssynergia in men with spinal cord injury

The Efficacy and Safety of Intrasphincteric Botulinum Toxin-A Injections in Patients with Non-Spinal Cord Injury-Related Detrusor Sphincter Dyssynergia: A Retrospective Study

Botulinum toxin-A (BoNT-A) injections into the external urethral sphincter are an established therapeutic procedure for reducing bladder outlet obstruction in patients with detrusor sphincter dyssynergia (DSD) due to spinal cord injury (SCI). Given the paucity of data on patients with DSD but without SCI, we aimed to assess the efficacy of intrasphincteric BoNT-A injections in this cohort. For this retrospective study, we screened all patients who underwent their first intrasphincteric BoNT-A injection at our institution between 2015 and 2021. The inclusion criteria were patients aged 18 years or older with neurogenic detrusor overactivity (NDO) and DSD with a maximum detrusor pressure (Pdetmax) of >40 cmH2O, confirmed via video-urodynamic studies (VUDS). The primary outcome was a reduction in Pdetmax and detrusor overactivity leak point pressure (DOLPP) during NDO-associated urinary incontinence posttreatment. The secondary outcome was a reduction in patients relying on indwelling urinary catheters posttreatment. We included 13 eligible patients (all male, median age 31 years, with different underlying neurological disorders, except SCI). All underwent intrasphincteric BoNT-A injections with either 100 (n = 7) or 150 (n = 6) units, respectively. Pdetmax during voiding was significantly reduced posttreatment (median 105 vs. 54 cmH2O, p = 0.006), whereas DOLPP remained unchanged (i.e., median 50 cmH2O). While seven patients relied on indwelling urinary catheters pre-treatment, all were catheter-free posttreatment. Intrasphincteric BoNT-A injections in patients with non-SCI related DSD appear feasible for reducing bladder outlet obstruction to a certain degree in this cohort and subsequently for reducing the rate of indwelling catheters.

Long-Term Surveillance and Management of Urological Complications in Chronic Spinal Cord-Injured Patients

Bladder dysfunction is a common complication after chronic spinal cord injury (SCI). Patients may experience renal function loss, urinary tract infection (UTI), urolithiasis, bladder cancer, and even life-threatening events such as severe sepsis or renal failure. Suitable patient care may prevent UTI and urinary incontinence, decrease medication use, and preserve renal function. As the primary goal is to preserve renal function, management should be focused on facilitating bladder drainage, the avoidance of UTI, and the maintenance of a low intravesical pressure for continence and complete bladder emptying. Currently, several bladder management options are available to SCI patients: (1) reflex voiding; (2) clean intermittent catheterization; (3) indwelling catheterization. The target organ may be the bladder or the bladder outlet. The purposes of intervention include the following: (1) increasing bladder capacity and/or decreasing intravesical pressure; (2) increasing bladder outlet resistance; (3) decreasing bladder outlet resistance; (4) producing detrusor contractility; (5) urinary diversion. Different bladder management methods and interventions may have different results depending on the patient's lower urinary tract dysfunction. This review aims to report the current management options for long-term bladder dysfunction in chronic SCI patients. Furthermore, we summarize the most suitable care plans for improving the clinical outcome of SCI patients.

Real-World Data Regarding Satisfaction to Botulinum Toxin A Injection into the Urethral Sphincter and Further Bladder Management for Voiding Dysfunction among Patients with Spinal Cord Injury and Voiding Dysfunction

Purpose: This study aimed to investigate improvement in voiding condition after the initial botulinum toxin A (BoNT-A) injection into the urethral sphincter among patients with chronic spinal cord injury (SCI) and voiding dysfunction. Moreover, subsequent surgical procedures and bladder management were evaluated. Materials and Methods: From 2011 to 2020, 118 patients with SCI and dysuria who wanted to void spontaneously received their first BoNT-A injection at a dose of 100 U into the urethral sphincter. Improvement in voiding and bladder conditions after BoNT-A treatment were assessed. Next, patients were encouraged to continually receive BoNT-A injections into the urethral sphincter, convert to other bladder managements, or undergo surgery. After undergoing bladder management and surgical procedures, the patients were requested to report improvement in voiding condition and overall satisfaction to bladder conditions. Then, data were compared. Results: In total, 94 male and 24 female participants were included in this analysis. Among them, 51 presented with cervical, 43 with thoracic, and 24 with lumbosacral SCI. After BoNT-A injections into the urethral sphincter, 71 (60.2%) patients, including 18 (15.3%) with excellent, and 53 (44.9%) with moderate improvement, had significant improvement in voiding condition. Patients with cervical SCI (66.6%), detrusor overactivity and detrusor sphincter dyssynergia (72.0%), partial hand function (80.0%), and incomplete SCI (68.4%) had a better improvement rate than the other subgroups. Only 42 (35.6%) patients continually received treatment with BoNT-A injections into the urethral sphincter. Meanwhile, more than 60% of patients who converted their treatment to augmentation enterocystoplasty (n = 5), bladder outlet surgery (n = 25), BoNT-A injections into the detrusor muscle (n = 20), and medical treatment (n = 55) had moderate and marked improvement in voiding dysfunction and overall satisfaction. Discussion: Although BoNT-A injections into the urethral sphincter could improve voiding condition, only patients with SCI who presented with voiding dysfunction were commonly satisfied. Those whose treatments were converted to other bladder managements, which can promote urinary continence, or to surgical procedures, which can facilitate spontaneous voiding, had favorable treatment outcomes.

Will repeated botulinum toxin A improve detrusor overactivity and bladder compliance in patients with chronic spinal cord injury?

Chronic spinal cord injury (SCI) can induce neurogenic detrusor overactivity (NDO), leading to urinary incontinence and renal damage due to low bladder compliance and high detrusor pressure during the storage and voiding of urine. In 2011, Botox^® (onabotulinumtoxinA, botulinum neurotoxin serotype A [BoNT-A]) was approved by the Food and Drug Administration for the treatment of NDO. Intradetrusor injection of BoNT-A has been shown to have clinical utility for the treatment of urinary incontinence, with consequent improvements in quality of life for patients. In the past 20 years, this treatment has been shown to be an effective treatment for patients with SCI refractory to antimuscarinic medication. The present review focused on publications in MEDLINE/PubMed relating to botulinum toxin to evaluate the treatment outcomes of repeated injection of BoNT-A, the mechanisms of action, results of clinical and urodynamic studies, and adverse effects.

The Therapeutic Effects and Pathophysiology of Botulinum Toxin A on Voiding Dysfunction Due to Urethral Sphincter Dysfunction

Neurogenic and non-neurogenic urethral sphincter dysfunction are common causes of voiding dysfunction. Injections of botulinum toxin A (BoNT-A) into the urethral sphincter have been used to treat urethral sphincter dysfunction (USD) refractory to conventional treatment. Since its first use for patients with detrusor sphincter dyssynergia in 1988, BoNT-A has been applied to various causes of USD, including dysfunctional voiding, Fowler’s syndrome, and poor relaxation of the external urethral sphincter. BoNT-A is believed to decrease urethral resistance via paralysis of the striated sphincter muscle through inhibition of acetylcholine release in the neuromuscular junction. Recovery of detrusor function in patients with detrusor underactivity combined with a hyperactive sphincter also suggested the potential neuromodulation effect of sphincteric BoNT-A injection. A large proportion of patients with different causes of USD report significant improvement in voiding after sphincteric BoNT-A injections. However, patient satisfaction might not increase with an improvement in the symptoms because of concomitant side effects including exacerbated incontinence, urinary urgency, and over-expectation. Nonetheless, in terms of efficacy and safety, BoNT-A is still a reasonable option for refractory voiding function. To date, studies focusing on urethral sphincter BoNT-A injections have been limited to the heterogeneous etiologies of USD. Further well-designed studies are thus needed.

Modulatory effects of intravesical P2X2/3 purinergic receptor inhibition on lower urinary tract electromyographic properties and voiding function of female rats with moderate or severe spinal cord injury

OBJECTIVES

To evaluate the role that intravesical P2X2/3 purinergic receptors (P2X2/3Rs) play in early and advanced neurogenic lower urinary tract (LUT) dysfunction after contusion spinal cord injury (SCI) in female rats.

MATERIALS AND METHODS

Female Sprague-Dawley rats received a thoracic Th8/Th9 spinal cord contusion with either force of 100 kDy (cN); moderate) or 150 kDy (cN; severe); Sham rats had no injury. Evaluations on urethane-anesthetised rats were conducted at either 2 or 4 weeks after SCI. LUT electrical signals and changes in bladder pressure were simultaneously recorded using cystometry and a set of custom-made flexible microelectrodes, before and after intravesical application of the P2X2/3R antagonist AF-353 (10 μM), to determine the contribution of P2X2/3R-mediated LUT modulation.

RESULTS

Severe SCI significantly increased bladder contraction frequency, and reduced both bladder pressure amplitude and intraluminal-pressure high-frequency oscillations (IPHFO). Intravesical P2X2/3R inhibition did not modify bladder pressure or IPHFO in the Sham and moderate-SCI rats, although did increase the intercontractile interval (ICI). At 2 weeks after SCI, the Sham and moderate-SCI rats had significant LUT electromyographic activity during voiding, with a noticeable reduction in LUT electrical signals seen at 4 weeks after SCI. Intravesical inhibition of P2X2/3R increased the ICI in the Sham and moderate-SCI rats at both time-points, but had no effect on rats with severe SCI. The external urethral sphincter (EUS) showed strong and P2X2/3R-independent electrical signals in the Sham and moderate-SCI rats in the early SCI stage. At 4 weeks after SCI, the responsiveness of the EUS was significantly attenuated, independently of SCI intensity.

CONCLUSIONS

This study shows that electrophysiological properties of the LUT are progressively impaired depending on SCI intensity and that intravesical P2X2/3R inhibition can attenuate electrical activity in the neurogenic LUT at early, but not at semi-chronic SCI. This translational study should be useful for planning clinical evaluations.

Lumbosacral spinal cord epidural stimulation improves voiding function after human spinal cord injury

Deficits in urologic function after spinal cord injury (SCI) manifest both as a failure to store and empty, greatly impacting daily life. While current management strategies are necessary for urological maintenance, they oftentimes are associated with life-long side effects. Our objective was to investigate the efficacy of spinal cord epidural stimulation (scES) as a promising therapy to improve bladder control after SCI. A bladder mapping study was undertaken for sixteen sessions over the course of four months in an individual with chronic, motor complete SCI. Varying combinations of stimulating cathode electrodes were initially tested during filling cystometry resulting in the identification of an effective configuration for reflexive bladder emptying at the caudal end of the electrode array. Subsequent systematic testing of different frequencies at a fixed stimulus intensity and pulse width yielded lowest post-void residual volumes at 30 Hz. These stimulation parameters were then tested in four additional research participants and found to also improve reflexive voiding efficiency. Taken together with SCI studies on step, stand, voluntary motor control and cardiovascular regulation, these findings further corroborate that scES has an all-encompassing potential to increase the central state of excitability, allowing for the control of multiple body functions, including the urological system.

[Efficacy of botulinum toxin A injections in the urethral sphincter in patients with difficulties to perform self-intermittent catherization]

PURPOSE

To evaluate safety and efficacy of botulinum toxin A injections in the urethral striated sphincter in patients with difficulties to perform self-intermittent catherization.

METHODS

In this prospective study, 12 patients suffering from upper motor neuron diseases (8 multiple sclerosis, 2 myelitis, 1 brain injury, 1 multi system atrophy) and with difficulties to perform self-intermittent catherization, defined by a ICDQ score>1 (Intermittent Catheterization Difficulty Questionnaire) have had injections of 100U BOTOX^® under EMG guidance in the urethral striated sphincter, for a total of 15 injections. Evaluations consisted of two questionnaires (ICDQ and PGI-A, Patient Global Improvement) 30 days after the injection.

RESULTS

30 days after the injection, ICDQ was improved with a mean decrease of the total score of 7.8 (SD=5.9, P<0,001). In the same manner, all the patients were improved with a mean PGI-A score of 2.3. In 73.3 % of cases, the PGI-A score was equal to 2 (improvement=much better), and in 20 % it was equal to 3 (improvement=a little better).

CONCLUSIONS

Botulinum toxin A injections in the urethral striated sphincter in patients with difficulties to perform self-intermittent catherization seem to safe and effective.

LEVEL OF EVIDENCE

4.