EFFICIENCY OF NIDUS FLUORESCENCE IN THE S URGICAL-TREATMENT OF OSTEOID OSTEOMA - A REPORT OF 17 CASES

Purpose of the study The severity of pain and functional disability co ntrast with the benignity and small size which characterize the osteoi d osteoma. This study evaluates the clinical and histological efficien cy of an intraoperative localization of the nidus by the tetracycline fluorescence test which is based on histomorphometric bone labeling te chniques. Material and Methods 17 out 25 osteoid osteoma, operated bet ween 1987 and 1995, had tetracycline fluorescence test. The patients r eceived 1 gramme orally during each of the 3 pre-operative days. Fluor escence under ultraviolet light was assessed on the removed specimen, and on the tumor site, before and after surgical resection. Results At a mean follow-up of 39 months (12-85), 15 of the 17 patients (88 per cent) were painless. The result was always acquired within the first w eeks after procedure. 2 patients had a primary failure due to incomple te removal of fluorescent nidus, and one was reoperated with success a fter one year. One patient had a false negative test although there wa s histological evidence of osteoid osteoma on the removed tissues with a complete relief of pain. In summary, the test was helpful in 14 cas es (82 per cent) guiding ''en bloc'' resection or curetage, and allowi ng 70 per cent of histological nidus diagnosis. Discussion This test i s easy to carry out by pre-operative ingestion of tetracycline and onl y requires an ultra-violet light source. It demonstrated a good reliab ility which can be compared with that of more complex radio-labeling t echniques or CT guided drill resections which impede histological conf irmation in half of the cases. The fluorescence test allows a secure a nd precise procedure without complication, and we use it mainly for ca ncellous and superficial osteoid osteoma, and for revision of previous failed excisions. When the nidus is cortical and deeply located, radi oguided techniques must be discussed.