Microarterial anastomosis using a noncontact diode laser versus a control study

Abstract

A series of direct carotid end-to-end laser anastomosis vs. direct manual suture was carried out on a series of 70 Wistar rats (mean weight 260 g). Both common carotids (0.8-1.2 mm) were sectioned and repaired. The left side (n = 70) was submitted to laser-assisted microvascular anastomosis (LAMA) performed by means of a diode laser device (wavelength 830 nm and power output 3 W in continuous wave) without chromophore. The right side (n = 70) underwent a control manual suture (CMA). The diode laser energy was delivered into a micromanipulator coupled to a Zeiss operating microscope with a focused spot of 300 microns in diameter. After placement of three 10.0 stitches for edge coaptation, the LAMA was achieved using laser shots (average 3) of 500 mW power, 4.5 s duration, and 700 W/cm2 irradiance each. The CMA was performed by means of six 10.0 stitches. The good vascular flow was confirmed by Doppler spectral analysis (n = 466) carried out from day 0 to day 90. Light and scanning electron microscopy (n = 82) showed that re-endothelialization after LAMA was gaining ground on day 3, whereas collagenous network developed in the media scar by day 10. In contrast, after CMA the arterial repair was delayed on day 20, inducing a media fibrotic scar. The patency rate was 93% in both anastomoses. The shorter operating time (13 min for LAMA vs. 22 min for CMA) and the noncontact laser technique are the main intraoperative advantages. The technical benefits of the diode laser are pointed out.

Quantitative changes in collagen levels following 830-nm diode laser welding

“…We have observed a decrease in the amount of collagen after laser irradiation with the condition following our previous report for LAMA [9]. The denatured collagen is cleaved by pepsin when extracted [8].…”

Arterial Wall Compliance after Diode Laser Assisted Microanastomosis: A Comparative Study with Conventional Manual Microanastomosis on the Rabbit Femoral Artery

“…Histological and ultrastructural studies contributed to a better understanding of the mechanisms of laser-induced microvascular tissue welding [14]. However, most studies regarding LAMA, in the current literature, do not provide data about the in vivo arterial diameter, compliance or the distensibility coefficient [6,10,11,15,16], although their role in long-term patency of anastomosis is generally acknowledged [4,[17][18][19][20]. We found no left-right di#erence in diameter, compliance, or distensibility coefficient in the rabbit femoral arteries before surgery.…”

“…The aim of this study was to compare, on the same animal, the compliance of two types of end-to-end anastomosis on vessels under 2 mm diameter: conventional manual microanastomosis (CMMA) with 10/0 stitches, and laserassisted microanastomosis (LAMA) [5,6] with diode laser. We designed an in vivo bilateral animal model in which each animal was used as its own control, allowing comparative studies of arterial compliance.…”

Laser-assisted vessel welding: state of the art and future outlook

“…Compared to conventional suture anastomosis (CSA), the potential advantages of laser vascular bonding include a reduction in foreign body reaction, liquid-tight sealing (i.e., immediate closure of the incision or wound that prevents bleeding or seeping of fluids from the perfused blood vessels), faster healing, and simpler and more rapid alternatives for minimally invasive and endoscopic anastomotic techniques [1][2][3]5,7,8,[10][11][12]14,16,17,[22][23][24]27,28,30,32,35,36,40,44,45,68,69].…”

“…First, the relatively low welding strengths produced with LAVW often require additional sutures to reinforce the anastomosis, ultimately defeating the purpose of the modality. [3,[5][6][7][8]10,[12][13][14]18,20,22,24,26,28,30,32,[34][35][36]40,67,69,70] Second, extensive thermal damage may extend to the basal membrane of the intima ( Figure 1) and cause intimal hyperplasia [7,20], thrombosis [7,26], and aneurysm formation [13,15,21,34,38,71,72]. To overcome these disadvantages, several more refined welding techniques have been developed, including sLAVW, scaffold-and solder-enhanced LAVW (ssLAVW) (Figure 2), and photochemical laser-assisted tissue bonding.…”