Both the transfrontal and the suboccipital-transcerebellar approaches are commonly used trajectories for frame-based stereotactic biopsies of brainstem lesions. Nevertheless, it remains unclear which approach is more favorable in terms of complications, diagnostic success and outcome, especially considering the location of the lesion within the brainstem. This study compared the safety and diagnostic yield of these two approaches and a brainstem zone model was created to answer the question, whether there is a favorable approach depending on the location of the lesion in the brainstem.

A retrospective analysis of 84 consecutive cases, which underwent frame-based stereotactic biopsy for brainstem lesions via either the transfrontal or the suboccipital-transcerebellar approach, over a 16-year period was performed. Clinical and surgical data regarding trajectories, histopathology, complications and outcome was collected. Subsequently, the brainstem was divided in anatomical zones to compare the frequency of use and the efficacy of the two approaches depending on the location of the lesions.

A total of n=84 stereotactic biopsies for brainstem lesions were performed. In 36 cases the suboccipital-transcerebellar approach was used, whereas in 48 cases surgery was performed via the transfrontal approach. Patients demographic data were comparable. Overall diagnostic yield was 90.5% (93.8% transfrontal vs. 86.1% suboccipital, p=0.21). Complications occurred in 11 cases, which adds up to a total complication rate of 13.1% (12.5% transfrontal vs. 13.9% suboccipital, p=0.55). The brainstem model showed a more frequent use of the suboccipital approach in lesions of the dorsal pons. The transfrontal approach was used more frequently for mesencephalic targets. No significant differences in terms of complications and diagnostic yield were observed, even though complications in medullary lesions appeared to be higher using the transfrontal approach.

This study showed, that if the approaches are used for their intended target locations there are no significant differences between the transfrontal and the suboccipital-transcerebellar approach for frame-based stereotactic biopsies of brainstem lesions in terms of diagnostic yield and safety. Therefore, our data suggests that both approaches should be considered for stereotactic biopsy of brainstem lesions.