Bioimpedance in neurosurgery for tumor margin delineation

The electrical properties of brain tissue, shaped by cellular composition, fluid content, and ion distribution, create measurable impedance differences that can be exploited intraoperatively [1-7]. Bioimpedance has emerged as a promising adjunct for guiding resection in gliomas and other brain lesions, offering real-time information beyond microscopic views, fluorescence, or MRI imaging.

This review synthesizes current evidence to assess whether bioimpedance can reliably delineate tumor margins in neurosurgery, evaluating differences between normal and pathological tissue and its potential for routine use.

We reviewed key studies (2014-2024) on bioimpedance in brain tissue, focusing on in vivo measurements, systematic analyses, and oncology applications, selected from PubMed and Scopus for relevance to intraoperative margin identification. Keywords included bioimpedance, brain tumor margins, glioma surgery, intraoperative monitoring, and neurosurgery. Two recent reviews by Georgiannakis et al. (2024) and Abboud et al. (2022) were included to provide up to date insights.

Recent studies confirm tumor tissue shows distinct resistivity compared with surrounding white and gray matter [1-3, 5, 8]. For example, Abboud et al. (2022) reported white matter at 13.3 ± 1.7 Ω m, peritumoral edema at 8.5 ± 1.6 Ω m, low-grade gliomas at 6.4 ± 1.3 Ω m, and high-grade gliomas at 5.0 ± 1.0 Ω m (enhancing) or 3.9 ± 1.1 Ω m (necrotic; p < 0.001). Though absolute values vary, differences between physiological white/gray matter and tumor remain consistently significant.

Methodological heterogeneity and lack of standardization prevent routine clinical application. Standardized protocols and larger-scale validation are needed to facilitate bioimpedance's role in decisions about the radicality of resection.