In vivo near infrared (NIRS) sensor attachment using fibrin bioadhesive

Abstract

Background: ‘Tisseel’ (Baxter Healthcare, Deerfield, IL) is a fibrin-based sealant that is commonly used during spine surgery to augment dural repairs. We wish to intra-operatively secure a near infrared spectroscopy (NIRS) sensor to the dura in order to monitor the tissue hemodynamics of the underlying spinal cord. To determine if ‘Tisseel’ sealant adversely attenuates NIR photon transmission. Methods: We investigated ‘Tisseel’ in both an in vitro and in vivo paradigm. For in vitro testing, we used a 1 mm pathlength cuvette containing either air or ‘Tisseel’ interposed between a NIR light source (760 and 850 nm) and a photodiode detector and compared transmittance. For in vivo testing, a continuous wave (760 and 850 nm) spatiallyresolved NIRS device was placed over the triceps muscle using either conventional skin apposition (overlying adhesive bandage) or bioadhesion with ‘Tisseel’. Raw optical data and tissue saturation index (TSI%) collected at rest were compared. Results: In-vitro NIR light absorption by ‘Tisseel’ was very high, with transmittance reduced by 95% compared to air. In-vivo muscle TSI% values were 80% with conventional attachment and 20% using fibrin glue. Conclusion: The optical properties of ‘Tisseel’ significantly attenuate NIR light during in-vitro transmittance and critically compromise photon transmission in-vivo.