The procedure is painful and deep sedation or general anesthesia is always required. Post-procedural pain control by anesthesiologist is mandatory as all the patients reported high-grade pain immediately after the ablation lasting around 2–3 h. Overnight stay in the hospital of the patient is preferable, and, generally, the patient can be discharged from the interventional radiology unit the day after the procedure.

Potential complications are rare and include iatrogenic damage to the surrounding nerve root or tissues due to the electrode placement, heat effect, and size of the bone necrosis [23]; protective measures include techniques of insulation and temperature or nerve function monitoring to protect vulnerable structures. Passive thermal protection techniques include continuous monitoring of the temperature in the area of interest by thermocouples or of nervous function by monitoring systems such as neurodiagnostic EEG and EMG and evoked potential electrodes [23, 24]. Measurement of the temperature in proximity to a neural structure or of the nerve’s functional ability during the ablation provides valuable information for a safe and efficient session.

Active thermal protection techniques include gas dissection, water dissection, and cooling media for skin protection (application of a sterile glove with iced saline, subcutaneous saline injection).

During gas dissection, CO₂ or air is injected for dissecting vulnerable structures from the ablation zone; generally CO₂ is insulated better than air, which is less soluble.

With precise CT guidance that allows multiplanar reconstruction (MPR) and protection techniques (i.e., evoked potential electrodes), very difficult OO can be treated safely (Fig. 10.4a–c). Follow-up of successful ablation is performed clinically, and there is no need for imaging follow-up in asymptomatic patients [18].

Traditional surgical treatment for osteoid osteoma includes wide excision with removal of a bone block, marginal resection of entire nidus, and curettage or high-speed burr techniques [25]. Comparison of these techniques to percutaneous imaging-guided ablation favors the latter in terms of minimal trauma, reduced functional restriction, and significantly lower cost [25].

RFA can be used as a treatment of larger benign tumors such as osteoblastoma (OB) (<3 cm in diameter) (Fig. 10.5); depending upon the diameter, a multipolar probe (allowing a larger ablation) and a longer ablation time can be required (Fig. 10.6).

While throughout the literature, there are reports of ablation in cases of eosinophilic granuloma, chondromyxoid fibroma, cystic hydroma, and aneurysmal bone cyst [18]. State-of-the-art reviews affirm that “essentially any small well defined lesion at imaging can be treated with RF ablation” [18].