Single arm pilot study to evaluate the safety and initial feasibility of the Neurolyser XR, a high intensity focused ultrasound device, for non-invasive treatment of axial chronic low back pain

Study design: Prospective, single arm

Timeline: six month enrollment period and 12 months follow-up period.

Sites: The study will be conducted at five sites in Canada: McGill University, Toronto Western, Silver Medical Group, Precision Sport & Spine, Kinetix Integrated Orthopaedic & Regenerative Medicine

Study population: Thirty adult patients diagnosed with facet related low back pain.

Primary study objective: Safety and efficacy of the Neurolyser XR for the treatment of chronic low back pain secondary to zygapophyseal joint syndrome.

Safety is measured by the incidence and severity of treatment related adverse events.

Efficacy is measured by the changes in pain severity at the treatment area, using a numerical rating scale (NRS), of 0 to 10 between baseline and 6 months.

Inclusion Criteria:

Adult male and females >55 years of age legally able and willing to participate in the study and come for follow-up visits Able and willing to fill the research questionnaires and to communicate with investigator and research team Patient with bilateral or unilateral low back pain of > 6 months duration Patients whose back pain is alleviated by recumbency or comfortable sitting position Patients presenting with a) a positive (>70% pain relief) to a previous, single or double, L1 to L5 lumbar medial branch block (within the last 12 months) and / or b) with a positive (>70% pain relief lasting more than 6 months) to a previous lumbar facet thermal radiofrequency denervation.

Average pain score of 6 or higher in the last month, (on 0-10 scale).

Exclusion Criteria:

Pregnant or breastfeeding patient Patients younger than 55 or older than 85 years Patients presenting with neurological deficits (including lumbosacral radiculopathy but not solitary radicular pain).

Patients with history of lumbosacral spine surgery excluding previous lumbar radiofrequency neurotomy Patients who have had lumbar radiofrequency neurotomy in the past 6 months Patients with the presence of metal hardware or other foreign objects at the lumbosacral spine Patients with history of lumbar spine pathology that may increase procedural risk and / or influence symptoms and / or generate unrelated adverse event, (per the discretion of the study PI) Patients unable to understand and complete the research questionnaires in the official language used within the particular sites' location.

Patients presenting with any severe medical condition preventing the patient from safely and effectively being treated in the study or reporting study outcome per PI decision.

Patient with extensive scarring of the skin and tissue overlying the treatment area.

Patients enrolled in or planned to be enrolled in another clinical trial during the duration of this research project Any patients with an uncontrolled coagulopathy Patients with known osteoporosis with absolute risk of spinal fracture of >10% over 10 years will be excluded Any patients with a history of malignant disease in the past five years Patients with rheumatologic diseases causing spine pain that are currently receiving active treatment including steroids, disease modifying drugs, biological agents or immunosuppressants.

Patients known for concomitant psychiatric disorders, excluding mood disorders. Patients presenting with concomitant mood disorders (deemed severe by the research physician).

Patients with a first-degree family member already enrolled in this study. Patient who is scheduled for any interventional/surgical procedure within 3 months from screening date Patients diagnosed with co-morbid multifocal chronic pain (e.g., fibromyalgia)