Frameless image-guided stereotactic brain biopsies: emphasis on diagnostic yield

Area of Science:

• Neurosurgery
• Neuropathology
• Oncology

Background:

• Frameless stereotactic brain biopsy often reports high diagnostic yield (DY) but low diagnostic accuracy.
• This discrepancy highlights concerns regarding the certainty and precision of diagnoses obtained through this method.
• A novel DY definition, incorporating diagnostic certainty and precision aligned with WHO CNS tumor classification, is proposed.

Purpose of the Study:

• To propose a standardized definition of diagnostic yield (DY) for frameless stereotactic brain biopsy.
• To evaluate the diagnostic yield and outcomes of 235 frameless stereotactic brain biopsy procedures over eight years.
• To identify predictive factors for inconclusive biopsies and postoperative complications.

Main Methods:

• A retrospective review of 235 consecutive frameless stereotactic brain biopsy procedures.
• Development of specific criteria for categorizing biopsy diagnoses.
• Analysis of predictive factors for inconclusive biopsies and postoperative complications, including age, glucose level, and intra-operative hemorrhage.

Main Results:

• The study achieved a diagnostic yield (DY) of 72.8% based on the proposed criteria.
• Inconclusive biopsy outcomes were 21.7%, and non-diagnostic outcomes were 5.5%.
• Age under 30 predicted inconclusive biopsies, while glucose level and intra-operative hemorrhage predicted postoperative complications (8.5% morbidity, 0.9% mortality).

Conclusions:

• The true diagnostic yield of frameless stereotactic brain biopsy is lower than commonly reported, likely due to a lack of standardized DY criteria.
• Standardization of DY criteria and definitions is essential for reliable interpretation of biopsy diagnoses.
• While considered safe, the procedure's diagnostic performance necessitates refined evaluation methods.