Introduction: It has been reported that osteoid osteoma may heal spontaneously.
Method: To elucidate the efficacy of conservative treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) for osteoid osteoma, clinical courses of the 15 patients with osteoid osteoma conservatively treated with NSAIDs were observed. Twelve out of the 15 patients took a usual dose of NSAIDs regularly (regular group).
Results: Except for one patient, all the patients of the regular group maintained pain-free state. Eight out of the 12 patients of the regular group were free of pain even after discontinuing NSAIDs in the average of 18.3 months (range 2-36 months). Because one patient of the regular group required twice the usual dose to maintain pain-free state, we performed surgical excision. The remaining three patients of the regular group were asymptomatic and still taking NSAIDs. The healing rate of the osteoid osteoma with regular dose of NSAIDs was 8/12 (67%) at the time of this study, which may be improved up to 11/12 (92%). On the other hand, mean period of time until spontaneous diminution of pain in the 14 patients conservatively observed without NSAIDs so far reported in the literature was 75 months (range 24-180 months).
Conclusion: Thus, osteoid osteoma is highly likely to heal spontaneously and administration of NSAIDs accelerates spontaneous healing. Therefore, conservative treatment with NSAIDs can be an important option other than surgical excision in treating osteoid osteoma.