MGH Department of Radiology - Osteoid Osteoma

Medical
Surgical
Radiofrequency Ablation (RFA)
Our Experience
Advantages of Radiofrequency Ablation (RFA)

Long-term pain control with drugs is an option:

The diagnosis can often be made with high levels of confidence from the symptoms and the appearance. No cases of malignant degeneration have been described. Although the tumors may increase very slightly in size, they do not grow significantly. They do not spread to other parts of the body. Therefore, it is not absolutely necessary for them to be removed. Sometimes these tumors may undergo spontaneous regression. Complete recovery has been reported in 3-7 years, however, this outcome is unpredictable, and in at least one instance a patient waited 18 years without relief before undergoing surgery.

Pain relief is usually achieved with the use of over-the-counter anti-inflammatory drugs such as aspirin, ibuprofen and acetaminophen. In our experience, the longest duration of relief is usually achieved with naproxen. Some patients report that medications may work for a while, and then stop working. In such instances it may be helpful to change to another anti-inflammatory.

Contra-indications to Medical Treatment:

In most instances, the only adverse affect of the tumor is continued pain and therefore long-term management with pain medication is an option. However, there is an option. However, there are certain times when removal of the tumor is preferred.

Intraarticular tumors (those within a joint) may cause an inflammation of the joint (synovitis), which may progress later to osteoarthritis.

When the tumor is near the growing end of a bone in a child, increased blood flow may cause either overgrowth or undergrowth of the limb.

Osteoid osteoma in the spine may cause a curvature of the spine in children, which may become permanent if allowed to persist for long periods of time.

Finally, some patients develop gastrointestinal problems from the use of anti-inflammatory medications. These may include heartburn, stomach ulcers and bleeding problems.

Operative treatment has been commonplace until recently. It is generally thought that for surgery to be successful, the tumor must be completely removed. More extensive surgery sometimes with bone graft has a greater chance of success, but a higher risk of complications and a longer recovery period.

Surgery requires a hospital stay of several days. Since many of these tumors are in major weight-bearing bones, the recovery period from surgery may require a long period of limited weight bearing, often with crutches.

Our experience indicates that this method is preferred whenever it is feasible. It is suitable for most lesions and has the shortest recovery time.

Candidates for the procedure:
Percutaneous radiofrequency ablation can be performed in patients with clinical and radiographic features typical of osteoid osteoma. The tumor should be clearly identified at a distance of not less than 1cm from vital soft tissues such as nerves and major blood vessels. A safe needle approach to the lesion should be available. This is usually determined by a CT (CAT) scan.

Anaesthesia/
If general anesthesia is to be used, it is important that nothing be eaten after midnight on the night before the procedure.

Most patients prefer general anesthesia, but the procedure can be performed using spinal or local anesthetic in some patients. The selection can be made after consideration of the exact tumor location and discussion of the alternatives.

Procedure:
The procedure is performed with CT guidance for localization of the lesion. Sterile technique is used.

Procedure Room A biopsy specimen is removed for histopathologic examination in each case. Subsequently a straight rigid electrode with outer diameter 1 mm and a temperature thermistor is introduced through the cannula into the same hole produced by the biopsy needle. The electrode is insulated throughout its extent except the terminal 5mm. The electrode is positioned in the center of the lesion to coagulate a sphere of tissue of 1cm diameter with the tip of the electrode at the center.

The electrode is connected to Radiofrequency generator. Grounding is achieved by an adhesive grounding plate. Sufficient current is used to heat the electrode tip to 85-90 C for 6 minutes. Subsequently the electrode and cannula are withdrawn. A simple bandage is applied at the puncture site.

Duration of the procedure: Approximately 2 hours, followed by another 2-3 hours in a recovery area. Patients are discharged in the afternoon of the procedure.

Recovery: There is often some pain on the day of the procedure. However, within 24 hours most patients are able to tell that the tumor is gone. Within 2-3 days most individuals are pain-free.

Post-Procedure advice:

Some patients with tumors in the legs may be advised to avoid vigorous sports activities such as long distance running or jumping for 3 months. No other activities are restricted. Two follow-up visits are performed, one after one month, and a second after one year. These can be done by local physicians.

We have treated over 200 patients with osteoid osteoma by this method.
There have been no complications at all, although a small number of recurrences are seen usually within the first year. About 10% of patients require a second procedure.

Should you wish to be treated at Massachusetts General Hospital:

We would be delighted to see you. However, before you come to Boston there are several things that should be done.

We would like to confirm the diagnosis of osteoid osteoma by reviewing the symptoms and the imaging studies. The CT scan is especially important, and is superior to MRI for this purpose. The CT scan will also help to determine whether there is a safe needle access to the tumor, and whether there are any important anatomical structures to be concerned about.

Review of the symptoms can be done by telephone or by a referral letter from your doctor. We should talk about the nature of the procedure so that you understand all the issues, including the availability of alternative treatments and the probability of success. This is best done after we review the images, because it will make the discussion more specific.

There will undoubtedly be some insurance issues to address. Our secretary is experienced at dealing with a variety of insurance plans. You may need a referral from your local doctor, especially if this is an issue related to coverage outside of the plan area. We can help you to identify places to stay and provide travel directions if required.

You will need to have someone to follow up on the treatment locally. If your local pediatrician or orthopedic surgeon is comfortable with having you consider this alternative he/she may be willing to do that. It would also be helpful if he/she performed a basic pre-anesthesia history and physical examination within a few weeks of the procedure. We have simple one-page forms for this purpose that we could send you. If your local doctor would prefer it, we would be happy to speak to him or her.

Advantages of (RFA) Radiofrequency Treatment compared to surgery:

1) Rapid pain relief usually apparent within 24 hours
2) Patient can bear full weight on the treated extremity immediately after the procedure
3) Little tissue damage - hence no structural weakening
4) No overnight hospital stay
5) Prompt return to work, school and other usual activities
6) Minimal post-procedure care
6) Lower cost