Real-time near-infrared spectroscopy monitoring of the paraspinal collateral network: comparison of two clinically available systems

Purpose: Efficacy of near-infrared spectroscopy monitoring of paraspinal collateral network (cnNIRS) has been shown to provide additional safety in extensive aortic repair. Better understanding of available cnNIRS monitoring systems regarding differences in performance for this specific purpose is required. Methods Two systems (FORE-SIGHT®, CAS Medical Systems, USA and INVOS™ 5100C; Medtronic, Ireland) used at 4 paravertebral levels (mid and lower thoracic, upper and lower lumbar) were compared in an acute large animal model during three different experimental sequences mimicking relevant clinical scenarios: segmental artery (SA) occlusion by (1) open-access clip-occlusion (n = 7), (2) endovascular coil-embolization (n = 9) and distal circulatory arrest via (3) aortic cross-clamping (n = 9). Results Significant differences in oxygenation measurements between devices were observed only at the lower thoracic level during SA clipping and aortic cross-clamping (p < 0.001). During SA clipping, FORE-SIGHT and INVOS demonstrated reduction to 85% and 72% of baseline values after occlusion of the mid-thoracic region, with mean differences between devices varying from 12.9 to 20.6% (p > 0.05) throughout the experiment. In the aortic cross-clamp sequence, reduction of values was observed in both devices, with FORE-SIGHT having less pronounces decrease during cross-clamping compared to INVOS (mean differences 1.0-14.7%, p > 0.05), and slower response to reperfusion after declamping (72 to 84% within 1 minute in FORE-SIGHT and 57 to 99% in INVOS). Conclusion Both devices provide similar cnNIRS monitoring applicability at mid-thoracic, upper and lower lumbar levels. INVOS seems to have a more rapid and pronounced response to open SA sequential occlusion and aortic cross-clamping at the lower thoracic level.