MR guidance and thermometry of percutaneous laser disc decompression in open MRI: an initial clinical investigation.

OBJECTIVES: To assess the feasibility, safety and efficacy of real-time MR guidance and thermometry of percutaneous laser disc decompression (PLDD).

METHODS: Twenty-four discs in 22 patients with chronic low-back and radicular pain were treated by PLDD using open 1.0-T magnetic-resonance imaging (MRI). A fluoroscopic proton-density-weighted turbo spin-echo (PDw TSE) sequence was used to position the laser fibre. Non-spoiled gradient-echo (GRE) sequences were employed for real-time thermal monitoring based on proton resonance frequency (PRF). Radicular pain was assessed over 6 months with a numerical rating scale (NRS).

RESULTS: PLDD was technically successful in all cases, with adequate image quality for laser positioning. The PRF-based real-time temperature monitoring was found to be feasible in practice. After 6 months, 21 % reported complete remission of radicular pain, 63 % at least great pain relief and 74 % at least mild relief. We found a significant decrease in the NRS score between the pre-intervention and the 6-month follow-up assessment (P < 0.001). No major complications occurred; the single adverse event recorded, moderate motor impairment, resolved.

CONCLUSIONS: Real-time MR guidance and PRF-based thermometry of PLDD in the lumbar spine under open 1.0-T MRI appears feasible, safe and effective and may pave the way to more precise operating procedures.

KEY POINTS: • Percutaneous laser disc decompression (PLDD) is increasingly used instead of conventional surgery. • Open 1.0-T MRI with temperature mapping seems technically successful in monitoring PLDD. • Pain relief was at least 'great' in 64 % of patients. • No major complications occurred. • Open 1.0-T MRI appears a safe and effective option for patient-tailored PLDD.