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Initial Experience with the use of Percutaneous Cryoablation for Osteoid Osteoma of the Spine: A Series of Cases 2012

Interventional Spine

Douglas, Yim, MD
Taoreed, Lawal, BS, Non ASSR Member
James, Martin, MD, Non ASSR Member
David, Monson, MD, Non ASSR Member
Robert, Bruce, MD, Non ASSR Member
John, Holbrook, MD, Non ASSR Member

Poster

Purpose

To demonstrate the safety and efficacy of percutaneous cryoablation as an alternative treatment of high-risk osteoid osteoma adjacent to critical neural tissue in the spine of pediatric patients. To our knowledge, this is the first report of cryoablation of osteoid osteoma in the spine of pediatric patients.

Methods & Materials

Patients were aged 10 and 17 years. Two lesions were located in the left L3 pars interarticularis and adjacent to the left S4 neuroforamina, respectively. Both lesions measured approximately 7 mm in diameter. The pars lesion was within 6 mm of the thecal sac and the exiting nerve root. The sacral lesion was within 5 mm of the exiting nerve root. In both cases, one 17G "Ice Rod" Cryo needle (Galil Medical) was placed under CT guidance within 1 mm tangent to the bony cortex such that the iceball, based upon the anticipated isotherm geometry per the manufacturer's published data, would migrate across bone into the tumor nidus. Cryoablation was performed with two freeze/thaw cycles under direct CT visualization. VAS and medication use were measured at 6 weeks, 3 months, and 6 months follow up.

Results

CT showed 70% of the anticipated ice sphere at 10 minutes of freeze. By extrapolation, this geometry meant that nerve elements came in full contact with the 0C and partially the -20C isotherms while the entire tumor nidus by the -20C isotherm. Both patients experienced complete resolution of pain and stopped taking NSAIDs immediately postprocedure. During the 6 weeks, 3 month, and 6 month appointments, the VAS for each patient was 0 and sustained. Both patients never resumed taking NSAIDs. The only minor complication occurred in the patient with the sacral lesion, as she experienced some numbness in the left inner thigh near the perineum, but shortly resolved.

Conclusion

Percutaneous cryoablation is a safe and effective alternative to radiofrequency ablation in treating osteoid osteoma, especially where critical structures such as the spinal cord and nerve roots lie dangerously close to the tumor nidus. Visualization of the ice formation provides the margin of safety to prevent lethal ice penetration into vital structures.

References/Financial Disclosures

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