Radio Frequency Ablation - The Magic treatment for Osteoid Osteoma

Osteoid osteoma is a relatively common benign bone tumour, always small in size (less than 2 cm) and painful. It occurs mainly in children and young adults. The basic radiological element is a distinctive small rounded area of osteolysis, the ‘nidus’, which consists of osteoid tissue surrounded by a halo of hyperostosis on radiographs or signal intensity on MRI. MRI and Radio-isotope bone scanning always reveals a rounded area of intense increased uptake and dynamic-contrast CT can distinguish it from osteomyelitis. The clinical feature of the lesion is local pain, typically more severe at night and often promptly responding to aspirin and other non-steroidal anti-inflammatory drugs. Other possible symptoms include growth disturbances, bony deformity, painful scoliosis, and if located within the capsule of a joint, swelling, synovitis, restricted movement, and contracture In recent years, several CT-guided percutaneous techniques have been used in order to achieve removal or destruction of the nidus with minimal tissue invasion, including percutaneous trephine resection, drill resection with or without the subsequent injection of ethanol, thermal destruction by means of laser photocoagulation or RF ablation. Materials and Methods: We studied eight patients (n=8) of Osteoid Osteoma over a time frame of one year. Six cases were on the inner aspect of the thigh and one on the Tibia. CT scan was done at three month and 1 year interval on all the patients. Results: All the cases (100%) showed excellent pain relief right from Day1. CT scan was done at three month and 1 year interval on all the patients. 7/8 (88%) showed complete resolution of the nidus in three months and 8/8 showed complete resolution at 1 year. Lesions of the cortical bone with intense reactive bone surrounding the nidus showed a greater tendency to ossify than those in subperiosteal or intramedullary locations. No biomechanical weakening caused by resorption of heated bone was seen. There were 0% complications and 0% recurrence. Summary: The main challenge in CT-guided RF ablation, as in other percutaneous techniques with a lack of histological verification, is not the procedure itself. CT-guided percutaneous RF ablation is a simple minimally invasive, safe and effective technique for the treatment of osteoid osteomas and can be regarded as the treatment of choice for most cases      Open surgery should be reserved for cases of diagnostic uncertainty, as well as for spinal lesions into which heat cannot be introduced without the risk of neurological damage. Keywords: Radiofrequency ablation, Osteoid Osteoma, Nidus