MRI-guided focused ultrasound (MRgFUS) to treat facet joint osteoarthritis low back pain--case series of an innovative new technique.

Objective: To evaluate the safety and efficacy of magnetic resonance-guided focused ultrasound (MRgFUS) to treat facet joint osteoarthritis pain.

Methods: Patients with a positive response to facet joint interventions were recruited from Pain and Spinal Clinics. Treatments were performed at the levels of pain according to symptomatology, previous invasive treatment and MRI grading of facet joint osteoarthritis. Both safety and efficacy data were collected. Pain palliation was evaluated using a validated pain numerical rating scale (NRS), Oswestry disability questionnaire (ODQ), Brief Pain Inventory (BPI) and the EuroQol (EQ-5D) health state score

Results: Eighteen patients were treated. There were no major adverse events. At 6/12 we found a reduction in both the NRS (average/worst) pain scores (60.2 %/51.2 %). This was associated with 45.9 % improvement in the ODQ score and 61.9 % reduction in the BPI interference score. We observed an improvement in the EuroQol (EQ-5D) health state score based on UK coefficients of +0.379 (0.317 to 0.696).

Conclusions: Our phase I observational pilot study has evaluated an innovative new technique that is both non-invasive and radiation free. It is the first description of this procedure in the literature. In all patients the technique was safe, free of complications, effective and well tolerated.

Key Points: Magnetic resonance-guided focused ultrasound offers non-invasive therapy for facet joint pain. MRgFUS appears to be an effective and safe thermal ablation technique for facet joint pain. Real-time image control and thermal feedback minimise complications. MRgFUS allows outpatient management of facet joint osteoarthritic low back pain.