Atypical cartilaginous tumours are usually treated
by curettage. The purpose of this study was to show that radiofrequency
ablation was an effective alternative treatment. We enrolled 20 patients (two male, 18 female, mean age 56 years
(36 to 72) in a proof-of-principle study. After inclusion, biopsy
and radiofrequency ablation were performed, followed three months
later by curettage and adjuvant phenolisation. The primary endpoint
was the proportional necrosis in the retrieved material. Secondary endpoints
were correlation with the findings on gadolinium enhanced MRI, functional
outcome and complications. Our results show that 95% to 100% necrosis was obtained in 14
of the 20 patients. MRI had a 91% sensitivity and 67% specificity
for detecting residual tumour after curettage. The mean functional
outcome (MSTS) score six weeks after radiofrequency ablation was
27.1 (23 to 30) compared with 18.1 (12 to 25) after curettage (p
<
0.001). No complications occurred after ablation, while two
patients developed a pathological fracture after curettage. We have shown that radiofrequency ablation is capable of completely
eradicating cartilaginous tumour cells in selective cases. MRI has
a 91% sensitivity for detecting any residual tumour. Radiofrequency
ablation can be performed on an outpatient basis allowing a rapid
return to normal activities. If it can be made more effective, it
has the potential to provide better local control, while improving
functional outcome. Cite this article:
Osteoid osteoma is treated primarily by radiofrequency
(RF) ablation. However, there is little information about the distribution
of heat in bone during the procedure and its safety. We constructed
a model of osteoid osteoma to assess the distribution of heat in
bone and to define the margins of safety for ablation. Cavities
were drilled in cadaver bovine bones and filled with a liver homogenate
to simulate the tumour matrix. Temperature-sensing probes were placed
in the bone in a radial fashion away from the cavities. RF ablation
was performed 107 times in tumours <
10 mm in diameter (72 of
which were in cortical bone, 35 in cancellous bone), and 41 times
in cortical bone with models >
10 mm in diameter. Significantly
higher temperatures were found in cancellous bone than in cortical
bone (p <
0.05). For lesions up to 10 mm in diameter, in both
bone types, the temperature varied directly with the size of the
tumour (p <
0.05), and inversely with the distance from it. Tumours
of >
10 mm in diameter showed a trend similar to those of smaller
lesions. No temperature rise was seen beyond 12 mm from the edge
of a cortical tumour of any size. Formulae were developed to predict
the expected temperature in the bone during ablation. Cite this article:
