Robot-assisted radiofrequency ablation versus open resection for osteoid osteoma: an analysis of perioperative outcomes and a rare case of malignant transformation

Introduction: Osteoid osteoma (OO) is a rare benign bone tumor predominantly affecting young individuals, with malignant transformation reported only in exceptional cases. This study aimed to compare clinical outcomes between robot-assisted radiofrequency ablation (RFA) and open surgical resection for OO and report a rare case of malignant transformation to osteosarcoma (OS). Methods: In this retrospective study, we reviewed data from 84 patients with OO treated between January 2014 and January 2024. Twenty-eight patients underwent robot-assisted RFA and 56 underwent open surgical resection. The evaluated outcomes included operative time, intraoperative blood loss, hospitalization duration, pain relief, and total medical costs. Results: The RFA group demonstrated a clear minimally invasive advantage, with significantly less intraoperative blood loss (6.4 vs. 78.2 ml, p < 0.001) and a shorter hospital stay (3.9 vs. 6.6 days, p = 0.003). However, the procedure required a longer operative time (130.0 vs. 97.6 min, p = 0.003) and incurred higher costs (35,715 vs. 26,959 CNY, p = 0.022). Both groups achieved a 100% initial success rate. The RFA group exhibited superior early pain relief, with significantly lower VAS scores on postoperative day 1 (p < 0.001). Two cases of malignant transformation to OS occurred in the RFA cohort. Conclusion: Robot-assisted RFA offers minimally invasive advantages over open resection, providing reduced blood loss, shorter hospitalization, and faster pain relief. However, its associated longer operative time, higher cost, and the potential for rare malignant transformation necessitate careful patient selection and stringent long-term follow-up.