Mayo Clinic Radiologist Performing Radiofrequency Ablation For Noncancerous Bone Tumors

"The problem with surgery is that intraoperative localization of the tumor can be quite difficult," Peterson says. If not totally removed, the tumor will grow back. And because surgeons can't tell exactly where the center of the tumor is, they compensate by removing a large portion of the bone. "This usually requires significant convalescence afterward," Peterson says. "In some cases that means non-weight bearing for a long period of time just to get the bone to heal. And if they've taken enough of the bone, it will put the patient at fracture risk."

Patients undergoing RFA usually have general anesthesia before the procedure, which takes about 90 minutes to two hours. Under CT guidance, which lets him see the tumor, Peterson introduces a biopsy needle through the patient's skin and into the center of the bone lesion. The hollow core of the needle provides a shaft through which he introduces a radiofrequency electrode. Power is turned on, and radiofrequency energy radiates out from the electrode, generating heat that destroys the tumor.

"The critical portion of the procedure is getting the biopsy needle in the exact center of the lesion," Peterson says. "CT can precisely obtain measurements down to less than 1 millimeter. So I can easily tell after doing a CT scan exactly where my needle is and where the tip of the electrode is going to be. Even though these are small lesions, CT has the capability of imaging them quite well."

No one knows what causes osteoid osteomas. Peterson says one theory is that they are a result of a traumatic injury, such as a fracture.

Encouraged by an older brother, Matthew Houser jumped off the top of his basement steps and broke his leg when he was a child. About 12 years later his leg started hurting him at the fracture site. After about six months of taking NSAIDs, the pain started getting worse. He underwent an unsuccessful surgery and an anesthetic injection before finally being diagnosed with an osteoid osteoma. He was referred to Mayo Clinic in Jacksonville where Peterson performed RFA. A few hours after the procedure, Houser was walking around pain free.

Though he needed no pain medication afterwards, some patients may need to take over-the-counter or prescription pain medication for a few days due to pain at the puncture site or pain in the bone.

"I decided to have it done," Houser says, "because it offered the quickest recovery, and because the doctors who recommended it were supposedly tops in their field. It's a relief that I won't ever have to deal with it again since they got rid of it."

Tumors larger than 1 centimeter in diameter will require repositioning of the biopsy needle and electrode for a second ablation. However, Peterson does not recommend RFA for tumors that would require more than two ablation cycles. And he says tumors close to arteries or veins and those in the spine should not be treated with RFA because of potential thermal injury to these vital structures.