(P 478) TREATMENT OF CHONDROBLASTOMA WITH PERCUTANEOUS CRYOABLATION

Objective: Chondroblastoma is a benign bone lesion typically located within the epiphysis and associated with considerable pain in teenagers and young adults. Recently, cryoablation has emerged as an alternative treatment to open curettage and bone grafting for these lesions, which may be particularly helpful in anatomic locations that are difficult to safely access without risk to surrounding structures.

Methods: Five patients were treated from 2018-2022 with single image-guided cryoablation using percutaneous needle access into the lesion, followed by introduction of 1.7mm cryoprobe for two, ten-minute freezing cycles with 5-minute thaw cycles. Patients were followed at a minimum of three months with serial imaging to evaluate for healing and complications.

Results: Mean age was 15.6±3.2years (5 females) and mean follow-up was 19.1±12.6. There were no immediate complications to the skin or surrounding bone, monitored clinically and with repeat CT scan at conclusion of procedure. Three patients (proximal tibia, proximal humerus, distal femur) were treated with cryoablation as the index treatment. These patients experienced pain relief and return to activities reliably between months 3-4 post-operatively and no signs of recurrence or degenerative changes at mean follow-up of 13 months. Two patients were treated with cryoablation in the setting of local recurrence following initial curettage. One of these patients experienced a similarly reliable recovery to those described above. The other patient had some improvement in pain following treatment but has experienced progression of degenerative changes which were in existence prior to cryoablation. In general, post-treatment changes showed increased sclerosis around the lesion on radiograph and resolution of bone edema on MRI.

Conclusion: Image-guided cryoablation was associated with pain relief and return to function by four months in most patients at short term follow-up. There was no detection of treatment-related complications such as skin necrosis or fracture at latest follow-up. Longer clinical and radiographic follow-up are warranted prior to broad application of these findings.