MR-HIFU for Non-invasive Thermal Therapy of Facet-Joint Syndrome:

Inclusion Criteria: * chronic low back pain * clinical diagnosis of Lumbar Facet Joint Syndrome * eligible for MRI and MR-HIFU session * eligible for general anaesthesia * intact skin and soft tissue over treatment zone * facet joint anatomy clearly identifiable * patients must be able to discontinue all pain relief medication for a minimum of 48 hours prior to baseline assessment * patients able to provide consent for the study Exclusion Criteria: * spinal implants * treatment target zone \< 10 mm from the skin * pregnant female patients * breastfeeding female patients * body weight \> 140 kg * systemic and/or local infections * moderate to high grade of spinal instability * MRI contrast agent contraindication * any MRI-unsafe implant or pacemaker * facet joint anatomy which is not targetable or reachable due to scars, surgical clips, implants, or prosthesis in the planned beam path of the ultrasound beam