Optical Coherence Tomography for the Evaluation of Energy Seals and the Subsequent Evaluation of the Thulium Laser as a Hemostatic Instrument

1. The development of an energy seal evaluation methodology using Optical Coherence Tomography. One-hundred and four avian embryonic vessels were subjected to Thulium laser irradiation at 1942 nm and subsequently imaged. Using both structural and Doppler feedback, several biomarkers were identified and used to classify irradiation outcomes as sealed or not sealed. The methodology developed here was compared to visual methodologies. It was found that the reported seal rate was dependent on the classification methodology (p = 0.01) where visual evaluation reported 18% more seals across the entire data set. The specificity of visual evaluation was dependent on the type of non-seal classification (p < 0.0001). Given that the developed methodology relied on the identification of biomarkers rather than user opinion, an objective evaluation methodology was achieved. Hemostatic systems evaluated visually should be re-evaluated.

2. Evaluating the Thulium laser as a hemostatic instrument. Average power, exposure time, and spot size were varied to maximize the seal rate. At sub 2 s exposure times the overall seal rate across all vessels was 29%. The highest seal rate achieved for a single condition was 60%. The rupture rate showed some correlation to average power.