7.P.23 RADIO FREQUENCY ABLATION (RFA) IN ORTHOPAEDIC ONCOLOGY; INDICATIONS AND COMPLICATIONS

Abstract

Radio Frequency Ablation (RFA) is a precise CT-guided technique to generate a small pre-defined field of dissecated tissue. Its’ present use in orthopaedic oncology is to treat osteoid osteoma. We have also treated other lesions with RFA and want to report our present indications and complications.

From 2005 to 2008 we performed 30 procedures: 23 osteoid osteomas, five low-grade chondrosarcomas, one chondroblastoma and one thyroid metastasis. Localisations were femur in 14 cases, tibia in 10, calcaneus in two, fibula in two, sacrum in one and scapula in one. All patients were treated with CT- guided RFA (Boston Scientific).

Follow-up for osteoid osteoma was done without additional imaging, all patients but one were pain free within 2 weeks; this one patient proved to have a chronic osteomyelitis although we thought we saw a nidus on CT. In one patient a burn wound complicated treatment because of unnoticed damage of the isolation layer of the probe. A free skin graft was necessary. We performed MRI controls and curettages for the chondrosarcomas in three patients, in one patient a fracture developed in the calcar femoris region after three months and a hip replacement was done. The patient with chondroblastoma is followed by MRI and there is no activity on contrast MRI two years after the procedure. In one lady a RFA was done for thyroid metastasis in the calcar femoris region. She fractured her collum femoris and got a hip replacement. In all tissue retrieved after RFA (curettage and hip replacement), there was complete necrosis of the tumour (chondrosarcoma grade one and thyroid metastasis).

RFA is an effective procedure for osteoid osteoma. Fracture and skin burns can occur. It is promising in low-grade chondrosarcoma and chondroblastoma. A study has been initiated recently to evaluate effectiveness of RFA in low-grade chondrosarcoma < 4 cm.