Stereotactic biopsy for brain lesions: Doing more with less

Abstract

Objectives: Stereotactic biopsy (STB) is a potential diagnostic tool considering its minimal invasiveness, high diagnostic yield, and minimal associated complications. Over the years, various frame-based instrument systems and frameless stereotactic biopsy systems have emerged to be employed in clinical use. With this study, we intend to get more by doing less in the form of STB for the patients of doubtful intracranial lesions treated over the past 5 years. We also want to highlight the technique of performing the procedure under scalp block, which can be used as a versatile tool in many clinical scenarios. Stereotactic biopsies may be planned even in rural district-level health facilities. One-time investment to procure instruments and avail existing imaging can lead to establishing definitive diagnoses in many doubtful cases. This will result in lesser cost and early establishment of treatment. Independent risk factors determining the outcome, such as deep-seated lesions, associated edema, and intraoperative hypertension, were studied. Establishing the diagnosis helped in prognosticating the disease, explaining the natural progression of symptoms, and starting adjuvant therapy. This tissue biopsy would also help secure samples for research and molecular analysis.

Materials and methods: Twenty patients underwent STBs at our institution between January 2018 and December 2022. We retrospectively analyzed patient characteristics, tumor pathology, surgical procedures, and outcomes, including the diagnostic value and surgery-related complications. These patients were followed up, and their progression-free and overall survival were analyzed. The need for adjuvant treatment was noted and analyzed. All procedures were performed using Cosman Roberts Wells® stereotactic frame. Pre-procedure magnetic resonance scans were performed at the time of admission. Contrast-enhanced computerized tomography (CT) scan after frame application was performed to identify targets and calculate the coordinates. A post-procedure CT scan was done to confirm the accessibility of the targeted lesion.

Results: The most common location of the tumor was a deep-seated thalamic lesion. A definitive diagnosis was established in 19 patients (95%) at the first STB. The diagnoses were glioma in 55% of cases, primary central nervous system lymphoma, tuberculosis, and demyelinating disorders in 10% of each, and a metastatic brain tumor in 1 (5%). The post-operative complications were all transient except in one patient with deterioration of motor weakness. The follow-up was noted, and modes of adjuvant treatment needed in these patients were recorded.

Conclusion: Stereotactic biopsy is a useful and effective method for achieving a definitive diagnosis and aiding in treating multifocal or small deep-seated lesions in or around eloquent regions.

Keywords: High-grade glioma; Local anesthesia; Lymphoma; Scalp block; Stereotactic biopsy.

Figure 1:

(a) Cosman-Roberts-Wells stereotactic biopsy set, (b) inserting biopsy needle, (c) pins placed in orbitomeatal line, (d) planning in work station.

Figure 2:

(a and b) Showing front and side views, respectively, of cranial nerves to be blocked. A-Supratrochlear nerve, B-Supraorbital nerve, C-Zygomaticotemporal nerve, D-Auriculotemporal nerve, E-Lesser occipital nerve, F-Greater occipital nerve, G-Great auricular nerve. (c and d) Showing scalp and forehead sensory innervation with dermatome-wise distribution. V1: Ophthalmic nerve, V2: Maxillary nerve, V3: Mandibular nerve.