Frame based stereotactic biopsy (FSB) remains the ‘gold standard’ for obtaining diagnostic samples of intracranial lesions to guide therapy. Nevertheless, diagnostic yield is highly variable.

The diagnostic yield from contemporary FSB is high and is dependent predominantly on lesion size. ¹⁾.

Stereotactic brain biopsy complications

A retrospective cohort study was conducted of all adult patients with imaging-documented lesions undergoing FSB at the Beth Israel Deaconess Medical Center between 2013–2018. Diagnostic accuracy, lesion characteristics associated with non-diagnostic biopsy, and surgical complications were evaluated. A biopsy was considered non-diagnostic if all frozen samples and the final pathology yielded normal brain tissue or non-specific reactive tissue unless the “reactive” pathology was consistent with radiation injury from prior therapy.

This search identified 198 FSB patients. Mean (SD) age was 62±17 years and 44.2% were female. The median procedure time was 32 minutes. A definitive histologic diagnosis was established in 187 cases (94.4% diagnostic yield). The mean lesion diameter was 31.9±16.8 mm. Multivariable logistic regression revealed only lesion diameter to be significantly associated with a diagnostic result (OR for the non-diagnostic result: 0.94 per mm diameter decrease, 95% CI 0.87-0.99, P=0.028). On univariable analysis, the diagnosis of CNS lymphoma appeared to increase the risk of a non-diagnostic biopsy (P=0.025), but this association disappeared when controlling for lesion size and steroid administration prior to biopsy. Eight patients (4.0%) developed postoperative hemorrhagic complications, three of whom required reoperation, and another expired.

This study demonstrates that diagnostic yield from contemporary FSB is high and is dependent predominantly on lesion size. ²⁾.

Hamisch et al. evaluated the feasibility, safety, and diagnostic yield of frame-based stereotactic biopsies (SB) in lesions located in deep-seated and midline structures of the brain to analyze these parameters in comparison to other brain areas.

In a retrospective, tertiary care single-center analysis, they identified all patients who received SB for lesions localized in deep-seated and midline structures (corpus callosum, basal ganglia, pineal region, sella, thalamus, and brainstem) between January 1996 and June 2015. Study participants were between 1 and 82 years. We evaluated the feasibility, procedural complications (mortality, transient and permanent morbidity), and diagnostic yield. We further performed a risk analysis of factors influencing the latter parameters. Chi-square test, Student t test, and Mann-Whitney rank-sum test were used for statistical analysis.

Four hundred eighty-nine patients receiving 511 SB procedures (median age 48.5 years, range 1-82; median Karnofsky Performance Score 80%, range 50-100%, 43.8% female/56.2% male) were identified. Lesions were localized in the corpus callosum (29.5%), basal ganglia (17.0%), pineal region (11.5%), sella (7.8%), thalamus (4.3%), brainstem (28.8%), and others (1.1%). Procedure-related mortality was 0%, and permanent morbidity was 0.4%. Transient morbidity was 9.6%. Histological diagnosis was possible in 99.2% (low-grade gliomas 16.2%, high-grade gliomas 40.3%, other tumors in 27.8%, no neoplastic lesions 14.5%, no definitive histological diagnosis 0.8%). Only the pons location correlated significantly with transient morbidity (p < 0.001).

In experienced centers, frame-based stereotactic biopsy is a safe diagnostic tool with a high diagnostic yield also for deep-seated and midline lesions ³⁾.

A report described the methodology, diagnostic yield, and adverse events (AE) associated with frame-based stereotactic brain biopsies (FBSB) obtained from 26 dogs with solitary forebrain lesions. Medical records were reviewed from dogs that underwent FBSB using two stereotactic headframes designed for use in small animals and compatible with computed tomographic (CT) and magnetic resonance (MR) imaging. Stereotactic plans were generated from MR and CT images using commercial software, and FBSB performed both with (14/26) and without intraoperative image guidance. Records were reviewed for diagnostic yield, defined as the proportion of biopsies producing a specific neuropathological diagnosis, AE associated with FBSB, and risk factors for the development of AE. Postprocedural AE were evaluated in 19/26 dogs that did not proceed to a therapeutic intervention immediately following biopsy. Biopsy targets included intra-axial telencephalic masses (24/26), one intra-axial diencephalic mass, and one extra-axial parasellar mass. The median target volume was 1.99 cm(3). No differences in patient, lesion, or outcome variables were observed between the two headframe systems used or between FBSB performed with or without intraoperative CT guidance. The diagnostic yield of FBSB was 94.6%. Needle placement error was a significant risk factor associated with procurement of non-diagnostic biopsy specimens. Gliomas were diagnosed in 24/26 dogs, and meningioma and granulomatous meningoencephalitis in 1 dog each. AE directly related to FBSB were observed in a total of 7/26 (27%) of dogs. Biopsy-associated clinical morbidity, manifesting as seizures and transient neurological deterioration, occurred in 3/19 (16%) of dogs. The case fatality rate was 5.2% (1/19 dogs), with death attributable to intracranial hemorrhage. FBSB using the described apparatus was relatively safe and effective at providing neuropathological diagnoses in dogs with focal forebrain lesions ⁴⁾.

Grand Challenge Veterinary Neurology and Neurosurgery: Veterinary Neurology and Neurosurgery – Research for Animals and Translational Aspects ⁵⁾.