Patients suffering from facet-joint-syndrome associated with lower-back pain will be treated with MRI-guided High Intensity Focused Ultrasound thermal therapy for pain relief.

Patients with diagnosed facet-joint-syndrome are suffering from severe pain in the respective regions, mainly lower-back pain. Eligible patients will be treated with High Intensity Focused Ultrasound (HIFU) under MRI control. The control by MRI assures on the one hand the correct selection of area to be sonicated and monitors in parallel the temperature, reached in the target area. The aim is to thermally ablate facet joint and/or medial branch nerves at lumbar spine. Ablation is deemed to be feasible and successful if temperatures of at least 57°C are reached at the target. The entire procedure will be done under anaesthesia.

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