Infrared (IR) lasers are being tested as an alternative to radiofrequency (RF) and ultrasonic (US) devices for hemostatic sealing of vascular tissues. In recent studies, a side-firing optical fiber was reciprocated, producing a linear laser beam pattern for sealing blood vessels. Challenges include limited field-of-view of vessel position within the device jaws, and matching fiber scan length to vessel size. A transparent jaw may improve visibility and enable custom treatment. Quartz and sapphire square optical chambers (2.7 x 2.7 x 25mm OD) were tested with a 1470nm laser and 550-μm-core fiber. Peak temperatures and cooling times were recorded on chamber surfaces. Angle polished fiber tips delivered 94% of light at a 90° angle. Porcine renal arteries with diameters of 3.4±0.7mm (n=13) for quartz and 3.2±0.7mm (n=14) for sapphire (P>0.05), were sealed using 30W for 5s. Reflection losses were 3.3% and 7.4% for quartz and sapphire. Peak temperatures on external chamber surface averaged 74±8 °C and 73±10 °C (P>0.05). Times to cool down to 37 °C measured 13±4s and 27±7s (P<0.05). Vessel burst pressures (BP) averaged 883±393mmHg and 412±330mmHg (P<0.05). For quartz, 13/13 (100%) vessels were sealed (BP>360mmHg), versus 9/14 (64%) for sapphire. Quartz provided more consistent seals and shorter cooling times than sapphire.
Previous benchtop studies demonstrated infrared (IR) laser sealing and cutting of blood vessels, in a sequential, two-step approach. This study describes a smaller, laparoscopic device design, and simultaneous approach to sealing and bisection of vessels. A 1470-nm IR laser sealed and bisected 40 porcine renal arteries, ex vivo. A reciprocating, side-firing, optical fiber, housed in a transparent square quartz optical chamber (2.7 x 2.7 x 25mm OD), delivered laser energy over an 11mm scan length, with a wide range of powers (41 to 59W) and treatment times (5 to 21s). Vessel diameters ranged from 2.5 to 4.8mm. All vessel cut ends were successfully sealed (80/80), as indicated by burst pressures greater than 360mmHg. The highest power, 59W, resulted in short times of 5 to 6s. Peak temperatures on the external chamber surface reached 103 °C. Time to cool down to body temperature was 37s. Infrared lasers simultaneously sealed and bisected blood vessels, with treatment times comparable to, and temperatures and cooling times lower than conventional devices.
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