Comparing Treatments for Refractory Overactive Bladder: Bladder Denervation vs Botulinum Toxin Injections

This randomized clinical trial aims to evaluate the effectiveness and safety of two third-line treatment options for women with refractory overactive bladder syndrome: selective bladder denervation using radiofrequency ablation and intravesical Onabotulinum toxin A injection.

The study includes 60 symptomatic female patients aged 18 years and older who met the eligibility criteria and had either failed to achieve adequate symptom control with at least two different oral pharmacological treatments or were unable to tolerate such therapies. Participants were randomly assigned into two equal groups, with 30 patients in each group, using the "Research Randomizer" tool.

Participant Assessments:

At the initial assessment, all participants underwent the following evaluations:

• A detailed medical history, including past surgeries and prior medication use.
• Urinary tests, including urinalysis and urine culture, as well as blood biochemical evaluations.
• Imaging with urinary system ultrasonography to evaluate both the upper and lower urinary tract and measure post-void residual urine volume.
• Symptom assessment using the following validated patient-reported outcome questionnaires:

International Consultation on Incontinence Questionnaire - Female Lower Urinary Tract Symptoms (ICIQ-FLUTS).

Overactive Bladder Symptom Score Questionnaire (OAB-V8). Incontinence Quality of Life Questionnaire (I-QOL).

Additionally, participants were asked to maintain a three-day bladder diary to document:

• The number of daily urinations.
• Episodes of waking up at night to urinate (nocturia).
• Urgency episodes.
• Instances of urge urinary incontinence.

Treatment Groups:

• Selective Bladder Denervation with Radiofrequency Ablation:

This procedure was performed under general anesthesia using the Apro Korea AK-F200 radiofrequency system, which operates with temperature and impedance control along with a cooling mechanism.

Radiofrequency energy was applied to four specific submucosal points in the bladder's trigone region.

The target tissue temperature was 100 degrees Celsius, with energy delivery set to 25 watts for 60 seconds at each point.

Post-procedure imaging and post-void residual urine measurements were performed to ensure patient safety.

• Intravesical Onabotulinum Toxin A Injection:

This treatment was administered under local anesthesia using a rigid cystoscope.

A total dose of 100 units of Onabotulinum toxin A was injected into ten separate points across the bladder wall.

Follow-Up Protocol:

Patients were scheduled for follow-up visits at 2, 4, and 12 weeks after the intervention. At each visit, the following evaluations were conducted:

• Ultrasonographic imaging of the urinary system to assess for any upper tract dilation (hydronephrosis) and to measure post-void residual urine volume.
• Laboratory assessments, including urinalysis and serum creatinine level evaluation.
• Reassessment of urinary symptoms through a repeat three-day bladder diary and completion of the same validated patient-reported outcome questionnaires.

Study Objective:

This clinical trial aims to compare the two treatment modalities concerning their effectiveness in relieving symptoms of overactive bladder, improving patients' quality of life, and assessing their safety profiles. The results of this study are expected to provide valuable insights into the optimal third-line treatment approach for patients with refractory overactive bladder who have not responded to conventional behavioral and pharmacological therapies.

Inclusion criteria

Biological females aged 18 years or older.

Diagnosis of refractory overactive bladder syndrome, defined as:

• Persistent symptoms despite having completed behavioral therapy and at least two different oral pharmacotherapies (e.g., anticholinergics or beta-3 adrenergic agonists) for a minimum of 3 months each; or
• Inability to tolerate oral pharmacotherapy for overactive bladder syndrome. Willingness and ability to provide written informed consent. Ability to comply with the study protocol, including attendance at scheduled follow-up visits and completion of validated symptom assessment questionnaires (e.g., Overactive Bladder Symptom Score - OAB-V8, International Consultation on Incontinence Questionnaire - Female Lower Urinary Tract Symptoms - ICIQ-FLUTS).

Exclusion criteria

Pregnancy or intention to become pregnant within 12 months of enrollment. History of stress urinary incontinence as the predominant symptom.

Recent interventions prior to enrollment:

• Oral medication for overactive bladder within the past 2 weeks.
• Intravesical Onabotulinum toxin A injection within the past 9 months.
• Pelvic electrical stimulation within the past 2 weeks. Active or chronic urinary tract infection or a history of urinary retention within the past 6 months.

Active hematuria or known bleeding disorders.

History or current diagnosis of:

• Bladder cancer or ongoing bladder cancer treatment.
• Bladder outlet obstruction, ureteral dysfunction, ureteral stricture, or vesicoureteral reflux.
• Elevated serum creatinine level (≥2 times the upper limit of normal) within the past 6 months.

Neurological conditions affecting bladder function, including but not limited to:

• Multiple sclerosis.
• Myasthenia gravis.
• Spinal cord injury or disease. Any condition deemed by the investigator to interfere with study participation or accurate evaluation of outcomes.