Laser welding of biomaterials stained with indocyanine green to tissues (original) (raw)
Related papers
Welding artificial biomaterial with a pulsed diode laser and indocyanine green dye
1995
ABSTRACT Laser tissue welding is a sutureless method of wound closure that has been used successfully in nerve, skin, and arterial anastomoses. We welded an elastin-based biomaterial that elicits minimal foreign body reaction to the intimal surface of porcine aorta. The aorta was stained with indocyanine green dye to efficiently absorb the 808nm diode laser light. Laser welding with a pulsed diode laser thermally confines heating to stained portion of tissue, minimizing adjacent tissue damage.
Lasers in Surgery and Medicine, 1988
Thermal fusion of intimal plaque with the arterial wall during coronary balloon angioplasty may significantly reduce the incidence of abrupt closure and may reduce the occurrence of delayed restenosis by improvement of luminal size and shape. Although Nd:YAG laser energy has been shown to be effective in the thermal fusion of plaque-arterial wall separations in vitro, the most efficient manner of energy delivery for rapid achievement of therapeutically useful equilibrium tissue temperature during laser exposure has not been defined. A comparison of weld strength achieved was therefore made between two formats of laser delivery: constant power vs. decremental power with an initial high dose followed by the minimal serial decrements necessary to maintain tissue temperature constant for 15 seconds. One hundred sixty-six tissue discs of human postmortem aorta of 11 mm diameter were studied. Intimal plaque was separated from the media, the two layers were juxtaposed, a force of 4 pounds was applied, and a fiberoptic-delivered laser beam was directed perpendicular to the tissue over a 3-mm-diameter nominal spot size. Weld strength was measured as the shear force required to separate completely the two tissue layers. The mean weld strength (75 g) achieved by use of the decremental power format was significantly higher (P < .01) than the mean strength (32 g and 56 g) achieved by using constant power for 20 and 30 seconds, respectively. The total laser energy used for the decremental power format was 235 joules, which was significantly less than the 320 and 480 joules used when constant power exposure for 20 and 30 seconds, respectively, was employed, despite the fact that the peak tissue temperature was similar for all three groups. It is concluded, therefore, that the use of decremental power to achieve quickly and, thereafter, to maintain a constant temperature provides better tissue weld strength at a lesser energy cost and hence is superior to the use of constant power.
Lasers in Medical Science - LASER MED SCI, 1992
The mechanism of laser bonding is not yet understood, but it is considered to be a thermal rather than a photochemical effect. The conditions required for successful anastomosis remain a controversial topic. In an alternative approach, in vitro tissue bonds were created over the temperature range 20–90°C without the use of a laser by approximating the tissue in a temperature controlled clamp. Bond integrity was assessed by measurement of breaking strength, and the effect of temperature and hydration on bond strength was examined. Bonds created under conditions of dehydration were significantly stronger than their hydrated counterparts. Temperature dependence was also observed, and bond strength significantly increased when temperatures exceeded the tissue denaturation temperature. As a result of these findings, a possible bonding mechanism is proposed.