Laser coagulation of blood vessels at 454 nm wavelength for neurosurgical interventions.

Significance: 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.

Aim: Therefore, a safer and more efficient microsurgical procedure is required to seal individual blood vessels.

Approach: Our approach uses a wavelength of 454 nm, 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 of different vessel diameters, the thermal damage, and the dynamics of the coagulation process using optical coherence tomography were investigated.

Results: Our findings show that laser radiation of 454 nm wavelength can reliably coagulate vessels up to $400\mu m$ in diameter with small thermal damage zones. Further research will be necessary to occlude larger vessels with a blood pressure of more than 120 mmHg.

Conclusions: Overall, we present a laser process that can fundamentally improve the safety and operation time in neurosurgical interventions.