Reliability of Frameless Stereotactic Brain Biopsy for Complicated Lesions: Multicenter Experiences

Background: This study aimed to report our experiences with the safety and reliability of frameless stereotactic brain biopsy, including eloquent areas and small-sized lesions. Materials and Methods: We reviewed 88 consecutive cases of brain lesions diagnosed with neuronavigation-guided frameless stereotactic biopsy in two different neurosurgical institutes (Turkey and Germany). In addition to a standard technique, magnetic resonance imaging (MRI)-computed tomography (CT) fusion images were used to enhance the accuracy of targeting. To stabilize the navigation system on the target, the deviation from average accuracy was set at 1 mm with MRI alone. The deviation from average accuracy was 0.5 mm on fused MRI-CT images. Results: There were 43 males and 45 females with a mean age of 62 years. The lesion diameter was ≤2 cm in 24 patients and >2 cm in 64 patients. The lesion was in the eloquent region in 16 patients. Histopathological diagnostic success rate was 98.8%. Overall, 56, 21, 5, and 3 patients were diagnosed with glial tumor, lymphoma, abscess, and metastasis, respectively, and 1 patient each with acute myeloid leukemia, radiation necrosis, and nonneoplastic neuroglial tissue was observed as a pathological result. Conclusions: The frameless biopsy system is gaining popularity because it is reliable and has a low complication rate. It provides rapid and accurate pathological results even for deeply located or small (size ≤2 cm) lesions. The frameless biopsy systems were used safely with a very high diagnostic accuracy rate according to the learning curve.