Radiofrequency thermoablation in the treatment of osteoid osteoma.

Abstract

Editor: We read with great interest the article of Dr Rosenthal and colleagues in the October 2003 issue of Radiology (1). It contains important information about the results of radiofrequency (RF) thermoablation in the treatment of osteoid osteoma. The article is particularly interesting not only because of the large series of cases reviewed (263 patients treated during 11 years) but above all because the minimum follow-up was 24 months. Although the advantages of RF thermoablation in the treatment of osteoid osteoma in comparison to surgical treatment are unequivocally reported in the literature, few studies have been published that have a long enough follow-up period to be able to state with confidence that this treatment is successful. In fact, in the literature, recurrences of surgically excised osteoid osteomas have been reported after only several months and, on exception, after several years. We, ourselves, have observed two cases of recurrence (osteoid osteoma of the femoral neck, recurrence after 15 years, and of the tibia, recurrence after 10 years). We began treatment of osteoid osteoma with RF thermoablation in June 2001, and by September 2003, we had treated 103 patients. We also treated four patients with recurrences (three surgically and one with a laser) and four vertebrae in four patients (two vertebral bodies and two arches). In our experience, albeit limited by time, we can confirm the difficulties reported by authors in treating patients with recurrences by using method other than RF thermoablation: Of the four patients with recurrences, we had one failure (in a patient who was treated subsequently with surgery), two improvements, and only one success. On the other hand, our results were better when we used RF thermoablation to treat patients who had initial treatment failures. We had only two failures in 15 patients. Like many other authors, we no longer perform biopsy routinely, because we think the agreement between clinical history and imaging is sufficient (radiography, computed tomography [CT], and scintigraphy with technetium 99m). However, we try to obtain a small sample of tissue when data do not match perfectly or when CT findings cast doubts on the morphology and volume of the nidus. We think it is extremely important to obtain CT scans with 1-mm contiguous sections and two-dimensional reconstruction in the three spatial planes, in both the planning and treatment stages (to choose the approach, type of needle, and number of sessions), and to check the position of the needle electrode. In our experience, which is limited by time, we have been able to verify that the constant thorough revision of our results has led to a continuous improvement in results and an optimization of the RF thermoablation technique, which has replaced routine surgery in the treatment of osteoid osteoma at the Rizzoli Orthopedic Institute.