The Effectiveness of Transcutaneous Sacral Neuromodulation Techniques-Magnetic Stimulation and Electrical Stimulation-on Detrusor Overactivity in Patients With Spinal Cord Injury

1. Neurogenic bladder frequently accompanies Spinal Cord Injury (SCI). Neurogenic bladder negatively affects the quality of life of individuals with SCI and constitutes a significant socio-economic burden. Therefore, objective evaluation of neurogenic bladder in individuals with SCI and the organization of a treatment program aimed at it is one of the most fundamental goals of SCI rehabilitation (1). Detrusor Overactivity (DOA) is the most common consequence of neurogenic bladder in patients with suprasacral SCI. DOA negatively affects the individual's quality of life by causing urinary incontinence, and on the other hand, poses a risk of structural and functional impairment in the upper urinary tract due to high intravesical pressures (2). Therefore, controlling high vesical pressures in SCI patients with DOA is important for both the protection of the upper urinary tract and increasing the patient's quality of life by ensuring continence. Pharmacological treatments, primarily anticholinergics, are the first-line treatment option for DOA. However, side effects associated with anticholinergics such as dry mouth, blurred vision, and constipation are frequently observed and can negatively affect medication adherence in SCI patients (3,4). On the other hand, in a group of patients, pharmacological treatments may be insufficient to reduce high intravesical pressures due to DOA to a safe limit. In this case, intravesical botulinum toxin-A injection and/or surgical options come to the agenda. Although intravesical botulinum toxin-A injection is considered minimally invasive, it is performed under local anesthesia with cystoscopy. It carries a risk of complications such as bleeding, albeit rarely. The necessity of repetition creates a cost burden, and there is also evidence that the effectiveness of repeated injections decreases over time (5). Surgical procedures involving augmentation cystoplasty have a higher cost and risk of complications (4). Recently, both technical developments and increasing evidence of efficacy have led to increased interest in the field of neuromodulation. Neuromodulation is the modulation of pain and motor activity with electrical or magnetic stimulation. Neuromodulation techniques aimed at controlling lower urinary tract dysfunction (LUTD) can be used through cortical, spinal, root, or peripheral nerves. Percutaneous or transcutaneous posterior tibial nerve stimulation (PTNS or TTNS), pudendal nerve electrical stimulation, sacral root electrical stimulation, sacral magnetic stimulation (SMS), and transcortical stimulation can be given as examples (3,6). Today, the relevant data on sacral neuromodulation is expanding (8,9). Electrical stimulation with electrodes implanted in the sacral roots is one of the neuromodulation methods used in DOA, but it is an invasive method. Transcutaneous neuromodulation applications, on the other hand, appear as treatment methods that are both lower in cost, safer, and easier to tolerate. As a reversible and minimally invasive treatment, sacral stimulation is considered a promising option and has become more widely used in recent years (8). Although data on the efficacy of sacral magnetic stimulation in urinary incontinence have increased, it is still a non-traditional treatment for neurogenic bladder (7, 10). New studies are needed to standardize the application methodology in clinical practice.

The study is designed as a prospective randomized observational study. It is planned to include 40 spinal cord injured patients who are receiving inpatient treatment at Ankara Bilkent City Hospital Physical Therapy and Rehabilitation Hospital and whose DOA symptoms and/or urodynamic findings could not be controlled despite anticholinergic treatment. Patients who meet the inclusion criteria will be included in the study, and informed consent forms signed by the patients agreeing to participate in the study will be obtained. Patients will be divided into two groups by computer-based randomization: one group will receive sacral magnetic stimulation and the other group will receive sacral electrical stimulation. Before the application, the patients' demographic data (age, gender, marital status, education level, occupation), characteristics related to spinal cord injury (duration of injury, level of injury, etiology of injury, neurological level according to the ASIA impairment scale, severity of injury), neurogenic bladder treatment characteristics, pharmacological treatments used for DOA and their side effects, and urine emptying method (indwelling catheter, aseptic intermittent catheterization (AIC), spontaneous voiding) will be recorded. For neurogenic bladder clinical evaluation:

• 3-day bladder diary (frequency of incontinence, volume voided and/or obtained by AIC/frequency of AIC and/or voiding)
• Neurogenic Bladder Dysfunction Score will be used.
• For urodynamic data, cystometry+EMG study results performed with the Libra+ (MMS, Enschede, The Netherlands) urodynamic measurement system, using double-lumen 8 F sterile urethral catheters and sterile saline at room temperature with a bladder filling rate of 20 ml/min, will be used.

The group to receive magnetic stimulation will be given a total of 1200 shots for 2 seconds with 28-second intervals, at a frequency of 10 Hz for 20 minutes, 5 times a week for 20 sessions, creating a feeling of contraction in the inner thigh or perineum, using the Magstim Rapid2 Magnetic Stimulator (Magstim, Whitland, Dyfed, UK) device available at our hospital. For repetitive magnetic stimulation of the sacral roots, the patients will be placed in the prone position, and 8 coils with an outer diameter of 70 mm will be positioned on the midline of the sacrum to cover the bilateral third sacral neural foramina.

Electrical stimulation will be applied symmetrically to both sides on the level determined to be over the S3 foramina by manual palpation of the sacrum, using 5x5 cm electrodes, and the current intensity will be increased until contraction is observed in the patient's external anal sphincter, at a current frequency of 20 Hz, pulse duration of 200 microseconds, 5 times a week for 20 minutes for 20 sessions. Sacral magnetic stimulation and sacral electrical stimulation to be applied to the patients will be performed by Dr. Zeynep YAKIŞIR at Ankara Bilkent City Hospital Physical Therapy and Rehabilitation Hospital. The applied treatments will not be invoiced to the Social Security Institution.

Parameters to be Examined (to be written individually and clearly)

1. Patients' demographic data (age, gender, marital status, education level, occupation)
2. Characteristics related to spinal cord injury (duration of injury, level of injury, etiology of injury, neurological level according to the ASIA impairment scale, severity of injury)
3. Neurogenic bladder treatment characteristics

• Pharmacological treatments used for DOA and their side effects,
• Urine emptying method (indwelling catheter, aseptic intermittent catheterization (AIC), spontaneous voiding) will be recorded.

For neurogenic bladder clinical evaluation:

• 3-day bladder diary (frequency of incontinence, volume voided and/or obtained by AIC/frequency of AIC and/or voiding)
• Neurogenic Bladder Dysfunction Score will be used. The evaluation will be applied 2 times: before and after the application.

For neurogenic bowel evaluation: Neurogenic Bowel Dysfunction Score

Spinal Cord Independence Measure (SCIM)

URODYNAMIC EVALUATION

• Urodynamic examinations will be performed with the Libra+ (MMS, Enschede, The Netherlands) urodynamic measurement system, using double-lumen 8 F sterile urethral catheters and sterile saline at room temperature, with a bladder filling rate of 20 ml/min.
• Bladder volume at first detrusor contraction
• Maximum detrusor pressure during the filling phase
• Bladder capacity at the end of filling: The volume at which urine leakage begins, or the maximum pressure the patient can tolerate, or a vesical pressure >40 cmH2O will be determined as the bladder volume.
• Bladder compliance (ml/cmH2O): bladder volume/detrusor pressure, 20 ml/cmH2O will be accepted as low bladder compliance.
• An increase in sphincter EMG during detrusor contraction will be accepted as detrusor sphincter dyssynergia and recorded as Present/Absent.
• If patients can void, post-void residual urine (PVR) will be recorded, and
• Bladder Voiding Efficiency (BVE, %) = voided volume / (PVR + voided volume) × %100 will be calculated.

Urodynamic evaluation will be applied 2 times: before and after the application.

Patients' satisfaction with the treatment will be evaluated with a 5-point Likert scale:

• Treatment Satisfaction Level - Likert Scale (1-5 points) (5=very satisfied, 4=satisfied, 3=neither satisfied nor dissatisfied, 2=dissatisfied, 1=not satisfied at all)

The level of discomfort caused by the treatment will be evaluated with a Visual Analog Scale (0-10 points):

• 0 = no discomfort, 10 = very uncomfortable