Efficacy and safety of frameless versus frame-based stereotactic biopsy for brainstem lesions: A comparison...

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.

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^® Statistical Package for the Social Sciences) software was used for statistical analysis, testing normality between groups with the Kolmogorov-Smirnov and Fisher's tests to assess the association of the use of each technique in the diagnosis, the complication rate and mortality, in addition to assessing whether the was a correlation between the effectiveness of the methods and the age group, gender, approaches, Karnofsky performance scale, location of the tumors, contrast-enhancing in images, with a 95% confidence interval.

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 P = 0.001.

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.