INTRAOPERATIVE GAMMA PROBE APPLICATION IN PATIENTS PRE-DIAGNOSED WITH OSTEOID OSTEOMA
Abstract
Introduction: Osteoid osteoma is a benign but painful bone tumor that is treated with the excision of the nidus. Due to difficulties in reaching the tumor, intraoperative localization may be needed for complete excision without unnecessary resection of the surrounding bone.
Aim: The aim of this study was to evaluate the effectiveness of intraoperative gamma probe application in the preoperative planning and for intraoperative localization of osteoid osteoma.
Material and Method: The study included a total of 26 patients, comprising 10 females and 16 males with a mean age of 19.6 years (range, 6-45 years), who were pre-diagnosed with osteoid osteoma based on clinical and radiological findings. All patients were admitted for surgery following bone scintigraphy. All operations were performed with the use of a gamma probe.
Results: Clinical results were obtained from the postoperative pain evaluation and excised bone tissue fragments were evaluated histopathologically. Localisation of the lesion area was made intraoperatively using a gamma probe in all patients. A statistically significant difference was determined between the radioactivity counts in the normal peripheral bones of the lesion and the lesion area itself (p<0.001).
The ratio of lesion to normal tissue was 4/1 on average. The radioactivity level dropped by 62% on average (30%-90%) in the cavity cleaned after post-resectional excision of the pathological tissue. The radioactivity counts in the cavity after resection were found to be significantly lower than those of the lesion area before resection (p<0.001).
Of the 26 patients included in the study, 21 were diagnosed with osteoid osteoma as a result of the histopathological analysis. Of 5 patients with a diagnosis additional to the osteoid osteoma, 2 were diagnosed with infection, 2 were diagnosed with enchondroma, and 1 was diagnosed with osteosarcoma. With the exception of the patient diagnosed with osteosarcoma, the lesions were excised using the gamma probe method in the remaining 4 patients.
Conclusion: The use of a gamma probe in intraoperative localization following a preoperative injection of Tc99m MDP, is an easy and safe method that helps in the localization of osteoid osteoma nidus during surgery and guides a limited but complete resection of the tumor.
Key Words: Osteoid Osteoma, Gamma Probe, Scintigraphy