Technical challenges and outcomes of stereotactic biopsies in the posterior fossa: Experience with ZD-inomed and leksell vantage frames.

Introduction: Stereotactic brain biopsies are essential for obtaining tissue samples from brain lesions, crucial for comprehensive histological analysis and subsequent adjuvant therapies. While most biopsies target supratentorial lesions, those involving the posterior fossa are less frequent but pose significant technical and surgical challenges, necessitating careful patient management.

Methods: We present our experience with stereotactic biopsies of the posterior fossa using the Leksell Vantage frame (Elekta, Stockholm, Sweden) and the ZD Inomed frame (Inomed Medizintechnik GmbH, Emmendingen, Germany). For the ZD frame, we either mounted it upside down or employed a frontal approach, while for the Leksell Vantage frame, we utilized a reverse x-axis orientation. Planning was based on 3-T MRI scans and preoperative MRI merged with stereotactic CT for coordinate generation.

Results: From 2006 to 2023, we performed 25 stereotactic biopsies of the posterior fossa in our department-9 with the ZD Inomed frame and 16 with the Leksell Vantage frame. The cohort included 14 male and 11 female patients, with an average age of 60.6 years (range 36-80 years). The average surgery duration was shorter with the Leksell Vantage frame (32.6 min vs. 44.8 min, p = 0.05). The average length of the planned trajectory was 41.7 mm for the Leksell Vantage frame and 52.2 mm for the ZD Inomed frame. Postoperativ bleeding occurred in two cases-one managed conservatively, the other required surgical intervention. Additionally, two other cases presented new postoperative focal neurological deficit. The overall mortality rate was 34.8% and a 40-day postoperative mortality rate of 13.0%.

Conclusion: Our experience demonstrates that stereotactic biopsies of lesions in the posterior fossa can be effectively managed with different frame systems, though they present a higher degree of complexity. Notably, the Leksell Vantage frame was associated with a significantly shorter surgery duration. This technical note provides valuable insights and detailed technical guidance for neurosurgeons facing similar challenges.