Laser-assisted Anastomosis Research Articles

Laser-assisted anastomosis of large-diameter vessels with the carbon dioxide laser

A low-powered carbon dioxide laser was used to accomplish large-vessel anastomosis in growing minipigs. Results showed excellent patency, near-normal growth rates, and minimal foreign body response.

Laser assisted vessel anastomosis of coronary arteries in vitro: Optimization of bonding conditions

Laser-assisted anastomosis of pigs' coronary arteries has been investigated using an Argon laser and a technique of applying an appropriate chromophore to the site of anastomosis. Remote infrared temperature measurements have shown that bonding was achieved at temperatures between 65 and 80°C corresponding to the collagen denaturation temperature and visual changes in the appearance of the tissue. Further laser irradiation produced carbonization and extensive tissue damage. Application of a chromophore at the site of anastomosis allowed a large reduction in the incident laser energy density. In end-to-end anastomosis, with only one supportive stay suture, bursting pressures of 90 to 310 mmHg (mean 203 mmHg) were achieved within a power range of 0.3 to 0.5 W with an exposure time of 50 to 210 s. Histological sections showed limited tissue damage but some variation in the vessel wall alignment which may explain variability in the mechanical strength. The laboratory studies have allowed us to optimize bonding conditions before embarking on animal tests.

Carbon Dioxide Laser-Assisted Microscopic Vasovasostomy

Microsurgical vasovasostomy has become an increasingly important part of the urologist's armamentarium. We have combined the C02 laser at milliwatt powers to achieve welding with microsurgical techniques. We divided 30 adult male Sprague-Dawley rats into six groups: sham surgery, vasectomy, control microsurgical anastomoses, laser-assisted anastomoses with sutures left in, laser-assisted anastomoses with sutures removed, and sutureless anastomoses. Laser-assisted anastomoses were achieved using a Bioquantum C02 laser coupled to a Wild operating microscope. Power densities ranging from 5.1 to 8.5 watts/mm2 were utilized. All animals were sacrificed after 6 weeks; light and scanning microscopy was performed. Our results show the feasibility of laser-assisted anastomoses, although some animals in the sutureless group had sperm granulomas and anastomotic strictures. Laserassisted anastomosis using sutures for alignment, whether sutures were left in or removed following laser treatment, appeared equal to control microsurgical techniques. However, it is noted that the muscle wall thickness in the area of the vasovasostomy was significantly reduced in the laser-assisted groups; this result may imply vas wall weakness.

Experimental CO2 Laser–Assisted Anastomosis of the Rat Fallopian Tube

ABSTRACT Laser-assisted anastomosis of blood vessels and other tubular structures has been performed experimentally with varying degrees of success. This study was undertaken to determine whether laser energy could be used to anastomose the ends of a severed rat fallopian tube. Thirty-six female white Sprague rats underwent laparotomy during which both fallopian tubes were exposed and transected. The right tube was anastomosed using conventional microsurgical technique. Anastomosis of the contralateral tube was accomplished by laser-assisted technique. Different groups of animals were reoperated upon at varying intervals at which time each fallopian tube was transected proximal to the anastomosis and patency was assessed. The anastomotic sites were removed and submitted for histologic examination, and the original anastomoses were replicated once. All animals were then mated. Ninety-seven percent of sutured and 100% of laser-assisted anastomosed tubes were patent, and 70% of the animals delivered normal o...

Anastomoses microvasculaires expérimentales utilisant le laser au CO 2: A propos de 240 anastomoses

In order to compare conventional microvascular suture anastomoses with CO2 laser-assisted anastomoses, 240 anastomoses were performed in Wistar albino rats. Average time required for anastomosis was 8.30 minutes in the laser group and 14.30 minutes using the conventional technique. Patency rate was the same in both groups for arterial anastomosis but in femoral veinous anastomoses, the patency rate was of 89% using laser and 75% when done by hand. Secondary vein thromboses amounted respectively to 2% with laser and 18% with conventional sutures. Scanning electron microscope examination revealed a better endothelialization in the laser group. T.E.M. examination showed an important inflammatory reaction around the threads in the conventional suture group, even at the end of the first month. In the laser group, a partial and transient necrosis of the media appeared between the second and fourth day. Laser assisted microvascular anastomosis seems to be a promising technique with potential clinical applications.

Laser-Assisted Trachea Anastomoses in Dogs

Tracheal anastomoses are known to be related to special surgical risks. We performed laser-assisted trachea anastomoses in 10 Beagle dogs, using an Argon-laser system and a handheld quarz fiber for energy transmission. All animals showed an uneventful postoperative course without signs of infection, air-leakage or respiratory impairment. Pathologic examination revealed no significant stenosis but a normal reconstruction of the tracheal endothelium and a normal woundhealing with only an increased connective tissue reaction. Because of the lower tensile strength of laser-assisted anastomoses in general, three adapting absorbable sutures should be left in situ to increase the resistance against mechanical stress. Under these circumstances laser-assisted anastomoses seem to be a promising additional method in the field of tracheal reconstruction and transplantation.

Laser-assisted microsurgical anastomosis.

A low power carbon dioxide laser was used to perform 212 end-to-end laser-assisted microvascular anastomoses (LAMA) of femoral arteries (mean diameter, 1.2 mm) in Sprague-Dawley rats. Eighty-two conventional microvascular suture anastomoses (CMSA) utilizing 10-0 monofilament interrupted sutures were done for comparison of techniques and wound healing. The mean duration of each anastomosis procedure was 16 minutes for the LAMA repairs, compared to an average of 27 minutes for the CMSA repairs (P less than 0.05). All anastomoses were patent at the completion of the procedure. Each laser-assisted anastomosis required an average of seven intermittent laser exposures of 0.1 to 0.3 seconds each with approximately 80 mW of CO2 (wavelength = 10.6 micron) radiation at a spot size of 150 micron. A patency rate of 95% was obtained on the LAMA vessels (202 of 212) compared to 96% for the CMSA repairs (79 of 82). A total of 14 aneurysms were noted in the LAMA group (7%) compared to 11 in the CMSA (13%). All aneurysms were in patent vessels. Histological analysis indicates that the progression of wound healing of LAMA and CMSA anastomoses follows similar paths chronologically and morphologically with increased scar tissue formation around the suture. Scanning electron microscopy confirms the comparable luminal healing of the LAMA and CMSA vessels, with complete reendothelialization occurring by 3 weeks postoperatively. The tensile strength of the LAMA repair, although low immediately after operation, is comparable to that of the intact artery at 21 days. These findings suggest that a low energy carbon dioxide microsurgical laser has potential beneficial clinical application for anastomosis of small vessels.

Vascular anastomoses with laser energy

Laser-assisted arterial and venous anastomoses are now feasible. A microscope-guided CO2 laser was used to deliver 60 to 100 mW to anastomose end to end 44 rabbit carotid arteries (1.5 to 2.0 mm) and 27 rabbit vena cavae (4 to 6 mm). These were compared with control arteries repaired with interrupted suture technique. Anastomoses were examined from between 24 hours and 19 weeks. Laser carotid anastomoses yielded 93% patency (41 of 44) and 9% aneurysms (4 of 44), whereas hand-sewn carotid anastomoses produced 91% patency (40 of 44) and no aneurysms. In the vena cava, 26 of 27 laser anastomoses were patent (96%) compared with 19 of 20 (95%) sutured controls. Venous aneurysmal dilatation was seen in 2 of 27 laser (7%) and in 3 of 20 (15%) hand-sewn anastomoses. Histologic examination of laser-assisted anastomoses showed local full-thickness thermal injury. Repair was by fibroblast and myofibroblast proliferation, and luminal cell coverage was complete by 14 days in both laser and sutured repairs. Laser arterial and venous anastomoses are attractive because of their simplicity and rapidity of performance. Their patency is comparable to sutured anastomoses, but arterial aneurysms remain a hazard despite use of extremely low laser energy. (J VASC SURG 1986;3:32-41.)

Vascular anastomoses with laser energy

Laser-assisted arterial and venous anastomoses are now feasible. A microscope-guided CO2 laser was used to deliver 60 to 100 mW to anastomose end to end 44 rabbit carotid arteries (1.5 to 2.0 mm) and 27 rabbit vena cavae (4 to 6 mm). These were compared with control arteries repaired with interrupted suture technique. Anastomoses were examined from between 24 hours and 19 weeks. Laser carotid anastomoses yielded 93% patency (41 of 44) and 9% aneurysms (4 of 44), whereas hand-sewn carotid anastomoses produced 91% patency (40 of 44) and no aneurysms. In the vena cava, 26 of 27 laser anastomoses were patent (96%) compared with 19 of 20 (95%) sutured controls. Venous aneurysmal dilatation was seen in 2 of 27 laser (7%) and in 3 of 20 (15%) hand-sewn anastomoses. Histologic examination of laser-assisted anastomoses showed local full-thickness thermal injury. Repair was by fibroblast and myofibroblast proliferation, and luminal cell coverage was complete by 14 days in both laser and sutured repairs. Laser arterial and venous anastomoses are attractive because of their simplicity and rapidity of performance. Their patency is comparable to sutured anastomoses, but arterial aneurysms remain a hazard despite use of extremely low laser energy.

Myelinated nerve fibers: computed effect of myelin thickness on conduction velocity.

Myelinated nerve fibers: computed effect of myelin thickness on conduction velocity.