Laser coagulation of blood vessels at 454 nm wavelength for neurosurgical interventions: occlusion rates, process dynamics and thermal damage

In neurosurgery, where operations take place near tissue structures with high functionality, precise devices for microsurgical procedures such as blood vessel coagulation are crucial. Currently, bipolar forceps that deliver up to 60 W with high alternating current are used for vascular coagulation (hemostasis) to thermally seal blood vessels and stop bleeding. However, the high current can disturb electrophysiological monitoring and cause nerve damage from heat spread. Our approach uses a 454 nm laser diode, which closely matches the hemoglobin absorption peak, to directly heat the blood and avoid thermal damage to surrounding tissue. In experiments on blood vessels at the vascular tree of pig hearts, occlusion rates at different irradiation durations, the temperature of the adjacent tissue, and the dynamics of the coagulation process using optical coherence tomography (OCT) were investigated. Our findings show that a laser radiation of 454 nm wavelength can reliably coagulate vessels up to 400 µm in diameter, offering a safe microsurgical method for neurosurgery.