Wireless, Implantable Tibial Nerve Stimulator System for the Treatment of Refractory Lower Urinary Tract Symptoms in Patients With Multiple Sclerosis

Inclusion Criteria: 1. Male or female aged 18 - 80; 2. Diagnosis of multiple sclerosis according to McDonald \[20\]; 3. Clinical stability over the past 6 months (no relapses and no disability progression, defined as worsening of ≥1 point in the EDSS score if reference EDSS is ≤5.5, and ≥0.5 points if reference EDSS is\>5.5); 4. One or more of: urinary frequency greater than 8 times/24 hours, urinary urge incontinence at least 2 episodes in 24 hours on 3-day voiding diary; 5. Urodynamic diagnosis of detrusor over-activity (DOA)and / or detrusor-sphincter dyssynergia (DSD); 6. Previous failure of conservative treatments (challenge over ≥6 months) i.e. lifestyle modification-fluid consumption, behavioral modification, and pharmacological therapy and stable OAB medications for at least 30 days; 7. No pharmacological treatment of overactive bladder (antimuscarinics and beta-3 agonists) for 2 weeks prior to screening; 8. Positive response to ongoing PTNS treatment defined as ≥50% reduction in urinary frequency, and/or ≥50% fewer incontinence episodes, or a return to normal voiding frequency (\<8 voids/day), based on retrospective diary review (treatment compliant and non-compliant patients) or PTNS treatment naïve able to sense tibial nerve stimulation (to be tested with TENS exam). 9. Competent sphincter mechanism and normally functioning upper urinary tract; 10. Leg circumference in the range of 20-30 cm at implantation site; 11. No contraindications for surgical intervention (e.g. being immunocompetent, no anticoagulant treatment, no current infection); 12. For female patients: using effective contraceptive methods; 13. Ability to comply with study requirements; 14. Having provided written informed consent. Exclusion Criteria: 1. Previous participation in another study with any investigational drug or device within the past 90 days; 2. Any metal implant in the area of StimRouter lead implantation site; 3. Anatomical defects that preclude use of the device; 4. Treatment with botulinum toxin injections, urinary incontinence surgery or implantation of artificial graft material, spinal or genitourinary surgery, abdominoperineal resection of the rectum or radical hysterectomy (female)/ prostatectomy (male) within the last 6 months; 5. Previous treatment with sacral neuromodulation; 6. Diagnosis of pelvic pain disorders, stress incontinence, current urinary tract infection, urinary stone and/or urinary tract malignancy; cystocele, enterocele or rectocele of grade 3 or 4; 7. Critical limb ischemia; 8. Previous or current pelvic radiotherapy and/or chemotherapy; 9. Severe uncontrolled diabetes; 10. Being prone to excessive bleeding; 11. Having a pacemaker or implantable defibrillator or other neural stimulation systems; 12. Exposure to diathermy or electrocautery; 13. Clinically significant peripheral neuropathy; 14. Neutropenic or immune compromised; 15. Pelvic radio- and/or chemotherapy; 16. Morbid obesity (BMI \>40); 17. Pregnant or lactating women, or women planning a pregnancy during the study, \<9 months post-partum; 18. Male: alpha-blocker for benign prostatic hyperplasia; 19. Allergy to local anesthetic or adhesive; 20. Life expectancy \<1 year.