Treatment Options for this Tumor:
In most cases, nonsteroidal anti-inflammatory medicines give substantial relief, and any history of taking these medicines should be carefully reviewed. If there is absolutely no relief of pain from taking NSAIDs, the diagnosis of osteoid osteoma is less likely. Lesions adjacent to a joint may cause ankylosis or mimic a pauciarticular inflammatory arthritis, such as Reiter's disease. The local swelling, erythema and tenderness can mimic infection. When there is significant involvement of a nearby joint, the relief from nonsteroidal medicines can be less dramatic.
Patients who respond well to NSAIDs and aspirin may be successfully treated with these medications until the lesion disappears. The average time to resolution is 22 months.
Many patients will not be able to tolerate the pain this long, and request surgical removal. For these cases, the goal is complete removal of the lesion by the least invasive means possible.
For lesions in the hindfoot and midfoot, radio thermal ablation by CT guided needle is the recommended technique. During radio thermal ablation, the tip of a radiofrequency generator electrode is placed into the center of the lesion under CT guidance and general anaesthesia. A radiofrequency generator forms an alternating high frequency radio wave that passes from the electrode tip into the surrounding tissue, where energy is dissipated as heat. The tissue itself is heated, not the radiofrequency probe. A sphere with a diameter of 1 cm can be effectively treated in this manner, making this treatment ideal for osteoid osteoma.
In order to be treated with radial thermal ablation, the diagnosis should be confirmed based on the imaging studies with a high degree of confidence. There should be sufficient distance between the lesion and any major neurovascular structure. The lesion should have a clearly deformed nidus less than 1 cm in largest dimension.
Although radio thermal ablation was previously only available in tertiary Medical Centers, it is now more widely available. The high success rate combined with the extremely low rate of complications strongly favor this technique. Radio thermal ablation can be difficult in the smaller bones because of difficulties with targeting the lesion in the CT scanner. In addition, when the lesion is in a small bone, there is risk of damage to nearby tendons or neurovascular structures.
For superficial lesions in the forefoot, open surgery is still the preferred treatment. The surgeon needs to be able to locate the nidus using radiographs, anatomic landmarks, and direct observation. Other techniques for locating the nidus have been described. The surrounding reactive bone can be extremely dense, and it may also be hypervascular and somewhat porous.