The Improvement in Clinical Outcomes with the Histological Presence of Nidus Following Radiofrequency Ablation (RFA) for Osteoid Osteoma (OO)

Authors: Amirul Adlan, Motaz AlAqeel, Scott Evans, Vaiyapuri sumathi, Mark Davies, Rajesh Botchu

Abstract:

Background & Objectives: Osteoid osteoma (OO) is a benign tumor of the bone commonly found in childhood and adolescence, causing bone pain, especially during the night. CT-guided radiofrequency ablation (RFA) is currently the mainstay treatment for OO. There is currently no literature reporting the outcomes of OO following RFA based on the histological presence of a nidus seen on a biopsy taken at the time of RFA. The primary aim of this study was to compare the clinical outcomes of OO between the group of patients with the presence of nidus on biopsy samples from RFA with those without nidus. Secondly, we aimed to examine other factors that may affect the outcomes of OO, reflecting our experience as a tertiary orthopedic oncology center. Methods: We retrospectively reviewed 88 consecutive patients diagnosed with osteoid osteoma treated with RFA between November 2005 and March 2015, consisting of 63 males (72%) and 25 females (28%). Sixty-six patients (75%) had nidus present in their biopsy samples. Patients’ mean age was 17.6 years (4-53). The median duration of follow-up was 12.5 months (6-20.8). Lesions were located in the appendicular skeleton in seventy-nine patients (90%), while nine patients (10%) had an OO in the axial skeleton. Outcomes assessed were based on patients’ pain alleviation (partial, complete, or no pain improvement) and the need for further interventions. Results: Pain improvement in the patient group with nidus in the histology sample was significantly better than in the group without nidus (OR 7.4, CI 1.35-41.4, p=0.021). The patient group with nidus on biopsy demonstrated less likelihood of having a repeat procedure compared to the group without nidus(OR 0.092, CI 0.016-0.542, p=0.008). Our study showed significantly better outcomes in pain improvement in appendicular lesions compared to the axially located lesions (p = 0.005). Patients with spinal lesions tend to have relatively poor pain relief than those with appendicular or pelvic lesions (p=0.007). Conclusions: Patients with nidus on histology had better pain alleviation compared to patients without nidus. The histological presence of nidus significantly reduces the chance of repeat interventions. The pain alleviation of osteoid osteoma following RFA is better in patients with appendicular lesions than spinal or axially located lesions.

Keywords: osteoid osteoma, benign tumour, radiofrequency ablation, oncology