Marina Ono, LucasSanz, ElisaArenillas Baquero, MarioMorillo, Maria del CarmenGiannetti, RomanoMuñoz, José DanielAlonso, EduardoCristobal, LaraMaldonado, Andres A.2026-07-272026-07-272026Marina Ono, L., Sanz, E., Arenillas, M., Morillo, M. D. C., Giannetti, R., Muñoz, J. D., Alonso, E., Cristobal, L., & Maldonado, A. A. (2026). Concentric Versus Delta Bipolar Probes for Intraneural Fascicle Selection: A Rabbit Model Study. Plastic and reconstructive surgery. Global open, 14(6), e7851. https://doi.org/10.1097/GOX.000000000000785110.1097/gox.0000000000007851https://hdl.handle.net/20.500.14352/138911Background: Bipolar stimulating probes are widely used during intraoperative monitoring in nerve surgery. However, there are no reports comparing different types of bipolar probes. We present the differences between 2 different bipolar probes (concentric and Delta) in a rabbit animal model for brachial plexus injury, focusing on their applicability for intraoperative neuromonitoring in peripheral nerve surgery. Methods: Using a previously described rabbit animal model, the biceps brachii muscle's compound muscle action potentials (CMAPs) were recorded after stimulation with increasing intensities (ranging from 0.2 to 3 mV) of the middle and lower trunks using both concentric and Delta probes. The correlation between stimulus intensity and CMAP amplitude was studied, as well as interstimulus amplitude variability. Results: Five rabbit brachial plexuses were studied. CMAP amplitude ranged from 0 to 9 mV. No correlation was found between stimulus intensity and CMAP for the Delta probe (Spearman rank test R = 0.181; P = 0.264). A strong correlation was found between stimulus intensity and CMAP using the concentric probe (Spearman rank test R = 0.74; P = 0.001). The Delta probe showed less variability (coefficient of variation 0.01 versus 0.1). Conclusions: Delta probes elicit highly reproducible, high-CMAP amplitude responses even with low-intensity stimuli. Concentric probes produce slightly less reproducible, progressively higher CMAP amplitudes with increasing stimulus intensitiesengAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/journal article2169-7574https://doi.org/10.1097/gox.000000000000785142317599open access636.09Veterinaria3109 Ciencias Veterinarias