Experience of neuroprotective air injection during radiofrequency ablation (RFA) of spinal osteoid osteoma.

purposeTo assess the usefulness of epidural air injection during the RFA treatment of spinal osteoid osteoma.

methodsA retrospective review of 17 patients who underwent RFA for spinal osteoid osteoma between September 2006 and May 2017 was performed. All the procedures were performed by a single radiologist. We reviewed the perioperative CT studies to assess the distribution of air relative to the osteoid osteoma. The clinical outcome of each patient group was evaluated during routine follow-up.

resultsSeventeen patients were treated for spinal OO (male:female 13:4; mean age was 16, ranging from 4 to 42). The nidus size ranged from 5.8 to 17.2 mm (mean 11.2). In nine cases epidural air injection was performed. In three cases the neuroprotective air was deemed satisfactory with a clear layer of air between the osteoid osteoma and the dural sac being visualised. In six patients adherence between the cortical bone immediately adjacent to the osteoid osteoma and the dural sac in contact was observed. In 15 patients the procedure was successful in terms of pain relief. No neural damage or other complication was reported in either group.

conclusionRFA is a safe treatment for spinal osteoid osteoma. Neuroprotective air injection does not appear to be necessary when performing the treatment in the spine. KEY POINTS: • Seventeen patients with spinal OO were treated with RFA, nine with air injection and eight without. Clinically successful treatment was achieved in 15 patients, with 2 subsequently undergoing surgery • In 6/9 cases the injected air failed to achieve separation between the osteoid osteoma and the thecal sac because of inflammatory adhesion • No complications were observed, regardless of whether neuroprotective air was instilled. Neuroprotective air injection appears unnecessary when treating spinal OO.