Simone Rouy

Morphologic changes in collagen fibers After 830 nm diode laser welding

The mechanism of laser tissue welding is elusive, but collagen transitions are somehow involved. Collagen fiber modifications observed after 830 nm diode laser welding are presented in this study.

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

The actual mechanism by which laser irradiation welds tissue is presently unknown; however, collagen is a major constituent of tissue welded by laser irradiation.

Interstitial diode laser hyperthermia in the treatment of subcutaneous tumor

Interstitial Laser Hyperthermia (ILH) has been investigated since the early 80s in the treatment of deep seated tumors. The purpose of this study was to evaluate the efficiency of diode ILH (830 nm) in a subcutaneous tumor model.

Biliary structures lead to tumour recurrences after laser‐induced interstitial thermotherapy

Thermal diffusion during laser‐induced interstitial thermotherapy (LITT) has not yet been fully investigated in heterogeneous tissue architecture such as liver. LITT was performed on rabbit liver tumours to analyse the role of biliary structures in thermal diffusion.

Diode laser and microvascular carotid anastomosis: A preliminary study

A crossed carotid end-to-end anastomosis was performed in 20 Wistar rats by means of a diode laser device (wavelength 830 nm and power output 3 W in continuous wave). The diode laser energy was delivered into a micromanipulator coupled to an OPMI 1 Zeiss operating microscope with a focused spot of 300 μm diameter. The vessel sealing was effected on common carotids (0.8–1.2 mm) using laser shots (average 9) of 680 mW power and 4.5 s duration and 962 W cm−2 irradiance each. The good vascular flow was confirmed by Doppler spectral analysis and angiography performed on days 0, 10 and 30. Light and scanning electron microscopy showed that reendothelialization was complete on day 10 whilst collagenous fusion of media and adventitia was obvious. The patency rate was 90% impaired by a lethal thrombosis. The efficiency of the diode laser was compared to that of other types of LAVA and to manual microanastomosis.

Morphological analysis of microarterial media repair after 830 nm diode laser assisted end-to-end anastomosis: Comparison with conventional manual suture

A series of 240 diode laser assisted end-to-end microvascular anastomoses (LAMA) and conventional manual anastomoses (CMA) were performed in the left and right common carotid of Wistar rats, respectively. In comparison with the two anastomotic methods, optic and scanning electron microscopic examinations were achieved from Day 0 to Day 210, in order to clarify the mechanism of media repair after diode laser welding, especially the long-term results. In the LAMA group, the cut vessel edges were welded without obvious thermal necrosis after laser treatment. On Day 10, media repair was underlined by circular bulges corresponding to the folds of cut vessel endings brought together. Inflammatory cells were regularly scattered in the adventitia in the vicinity of the anastomotic site, and were gaining ground intensively in the media by Day 20. At this time, the parallel organization of elastic laminae disappeared while the collagen network developed. On Day 120, irregular elastic fibres aggregated in the anastomotic site. On Day 210, reconstituted elastic lamina was present. In the CMA group, on Day 20, fibrotic repair appeared between cut vessel edges, and the injury incorporated by sutures was important. The elastic laminae were not reconstituted by Day 210 in any case. This microscopic study proves that the long-term repair of diode LAMA facilitates media repair and prevents fibrotic scarring of the media.

Microvascular carotid end-to-end anastomosis with a compact diode laser equipped with an auto-stop system: a preliminary study

Diode laser assisted microvascular anastomosis (LAMA) versus control ateral conventional suture microanastomosis (CMA) were performed in 50 rats. The laser source (830 nm) was included into a micromanipulator without optical fiber connection. The beam was directly focused on a deviating mirror giving a 200 micrometers spot size. The LAMA was performed on the left common carotid by means of 3 laser shots of 360 mW power and 8 s exposure time regulated by an auto-stop system, the irradiance being 1,146 W/cm2. CMA was performed on the right carotid by means of size 10.0 Ethilon stitches (BV 70, Ethnor, Neuilly, France). The anastomoses were evaluated by macroscopic controls and Doppler spectral analysis (D0 to D60). After LAMA, light and scanning electron microscopy visualized the rapid re-endothelialization of the anastomotic line with longitudinal migration of endothelial cells, while the media was repaired by collagen network due to tissular fusion. The procedure demonstrated the usefulness and the adaptability of our new laser system. The prototype, characterized by low weight (2,500 g), small size 30 X 10 X 6 cm), good laser transmission, equipped with a feed-back system is well adapted to microsurgery.

Morphological study of the healing process after diode laser-assisted end-to-end microanastomosis: comparison with conventional manual suture

A series of carotid end-to-end diode laser assisted microvascular anastomosis (LAMA) versus control ateral conventional suture microanastomosis (CMA) were performed in 120 Wistar rats (in the same animal, LAMA performed in the left side and CMA in the right). The optic and scanning electron microscopic examinations were assessed from day 0 to day 210. The results revealed that on day 0 LAMA gave rise to proteins deneturation and collagens fusion of the media and adventitia in the arterial wall. Re-endothelialization of anastomotic line began at day 3, as well as a large number of inflammatory aggregated in the adventitia. On day 10 the endothelial cells were restored on the anastomotic site and collagenous network developed in the media. On day 90 proliferation and disorientation of the elastic fibers appeared. A part of elastic laminae had been reconstructed on day 210. In the group CMA, the re- endothelialization developed later than LAMA, and the reconstruction of the elastic laminae failed to happen until day 210. These data suggest that the results of long term healing process after diode LAMA is better than that of CMA in normal artery repair.

Microarterial anastomoses using the diode laser: long term morphological results

In a series of 70 Wistar rats submitted to a noncontact diode laser-assisted carotid end-to-end anastomosis (LAMA) versus controlateral manual suture microanastomosis (CMA), contrast angiography and scanning electron microscopy were performed in a group of 18 animals at a long-term follow up of 7 months after operation. The investigation of angiography realized by means of a CGR General Electric DG 200 with a 512 digital matrix gave precise images of vessel wall repair and vessel patency. It permitted a simultaneous comparison between laser and manual anastomosis. Patency rate was 83% in LAMA and 78% in CMA. Nonlethal complications such as 1 stenosis, 2 thromboses in LAMA and 1 stenosis, 2 thromboses, and 1 pseudoaneurysm in CMA were observed. The results could be correlated to scanning electron microscopy findings and confirmed the morphological superiority of the laser technique.

Diode laser and microvascular anastomosis-long term follow up

Direct diode laser assisted carotid end-to-end microanastomosis (LAMA) versus contralateral manual sutures microanastomosis (CMA) were performed in 70 Wistar rats. The laser beam- wavelength 830 nm, maximum power 3 W and continuous wave was transmitted through a micromanipulator and provided a focused spot of 300 micrometers in diameter. After placement of three 10.0 stitches for edge coaptation, LAMA was achieved on left common carotid (0.8 - 1.2 mm) using laser shots (average 3) of 500 mW power, 4.5 s duration and 700 W/cm2 irradiance each. CMA was performed on right carotid by means of six 10.0 stitches. Light and scanning electron microscopy (n equals 82) showed in LAMA that re-endothelialization was complete on day 10 while collagenous fusion of media and adventitia was evident. The patency rate was 93% after LAMA versus 93% after CMA. The intra operative advantages of LAMA versus CMA: shorter operating time minimizing organ ischemia (13 min versus 22 min) and reduced endothelial trauma were evidenced. The technical advantages of diode laser were pointed out: small size of device, absence of water cooling system, no maintenance and decreasing price of diodes.