Efficacy and safety of frameless versus frame-based stereotactic biopsy for brainstem lesions: A comparison demonstrating comparable outcomes with frameless technique.

Background: The brainstem tumors are rare and extremely heterogeneous, presenting significant challenges in the surgical approach. For lesions that are not candidates for surgical resection, a definitive diagnosis is primarily obtained through stereotactic biopsy. However, the diagnostic yield, safety, and complication rate of frameless stereotactic techniques are still subject of debates in the literature, especially in eloquent or deep regions such as the brainstem. The aim of this study is to demonstrate that the frameless technique can achieve similar results to the frame-based technique, by comparing the results of the both techniques, even in critical regions, such as the brainstem. Methods: Twenty-nine frame-based stereotactic biopsies and 17 frameless biopsies of brainstem lesions were analyzed. Diagnostic confirmation of the lesions was performed through histopathological and immunohistochemical analysis and compared between the two groups of patients. The Statistical Package for the Social Science (IBM Results: Furthermore, it was observed that the only factor studied that increased the efficacy rate was the use of the transfrontal route, with an overall efficacy rate of 78.3% (36 patients) and Conclusion: The frameless and frame-based stereotactic techniques not show statistically significant differences in terms of diagnostic yield, complications rates and mortality. Both can be used depending on the availability and experience of the service, offering flexibility in choosing the approach for biopsy of brainstem lesions.