STUDY DESIGN: Two cases are reported in which an osteoid osteoma of the lumbar spine was treated with CT-guided thermocoagulation. OBJECTIVES: To review an alternative and minimally invasive treatment for spinal osteoid osteomas. SUMMARY OF BACKGROUND DATA: Surgical resection of a spinal osteoid osteoma can, depending on the location, be a formidable undertaking. Bone scintigraphy can be helpful in intraoperative identification. More recently, resection through a computed tomography-guided drill hole was found to minimize exposure. Using a thermocoagulation probe, as has been used in osteoid osteoma of the extremities, may be technically easier and cause less morbidity. METHOD: With the patient under general anesthesia, a bone biopsy cannula was introduced into the center of the osteoid osteoma. Material was subjected to histologic examination. A thermocoagulation probe was then inserted and heated to 90 C for 4 minutes. The two patients were kept overnight for observation. RESULTS: Both patients had complete pain relief and no evidence of recurrence after 2 years' follow-up. There were no complications. Scoliosis resolved in one patient and persisted in the other. CONCLUSION: Percutaneous computed tomography-guided thermocoagulation is a minimally invasive and technically straightforward method to achieve ablation of a spinal osteoid osteoma. No complications were encountered in these two patients. Future research should focus on the safety of thermocoagulation, especially cephalad to the level of the conus medullaris.