Effects of electrocautery, CO2 laser, and contact Nd:YAG laser scalpel on the healing of intestinal incision

Experimental Study on the Morphological and Functional Recovery following Partial Glossectomy in Rabbits: A Comparison between CO2Laser and Electrocautery

OBJECTIVE

The aim of the present study was to evaluate and compare the morphological and functional recovery following partial glossectomy in rabbits with the CO(2) laser and electrocautery.

METHODS

Partial glossectomy with the CO(2) laser or electrocautery in rabbits was performed to investigate changes in the body weight and tongue width after surgery. The study models were classified into three groups. In group 1, the excised edges of the wound were left unsutured after partial glossectomy with the CO(2) laser. In group 2, the wound was closed after CO(2) laser surgery. In group 3, as a control group, the wound was closed after partial glossectomy with electrocautery. The specimens of the tongues obtained from the rabbit were microscopically assessed.

RESULTS

No significant differences were found in the percent change in the body weight among the three groups. There was a significant difference in the tongue width between groups 1 and 3 at each time point: 2 weeks (p < 0.05), 4 weeks (p < 0.01), and 8 weeks (p < 0.001) postoperatively. Furthermore, there was a significant difference in the tongue width between groups 2 and 3 at 8 weeks (p < 0.02) postoperatively. Histologically, the scar tissue of the wound was extensive in the control group, although it was localized in the laser group.

CONCLUSION

Postoperative dysfunction was reduced when excised edges were left unsutured after partial glossectomy with the CO(2) laser.

Sharp Dissection, Electrosurgery, and Argon-Enhanced Electrosurgery in Porcine Skin Flaps

Sharp scalpel dissection, electrosurgery, and argon-enhanced electrosurgery (argon beam coagulation) were used to elevate random pedicled skin flaps in a randomized, blinded fashion with a porcine model. A total of 72 flaps on 9 pigs were examined. Flap survival was quantified, and histology was also reviewed 2 and 6 weeks after surgery. No significant difference among the three techniques was noted in terms of area or length of surviving flaps. There were also no histologic differences noted with regard to fibrosis, inflammatory infiltrate, or necrosis. We conclude that the use of electrosurgery during surgical dissection of random pedicled skin flaps is not detrimental to wound healing or tissue survival, and it provides benefits such as decreased blood loss, absence of the need for sharp instruments in the surgical field, and faster operative times.

Controlled temperature tissue fusion: argon laser welding of canine intestine in vitro

BACKGROUND AND OBJECTIVE

Thermal denaturation of proteins is recognized as a rate process governed by the local temperature-time response and is believed to be the principal mechanism for photothermal tissue welding. Since rate processes are exponential with temperature, feedback control of tissue surface temperature is hypothesized to create a quasi-constant rate of denaturation that will enhance the tissue welding process.

STUDY DESIGN, MATERIALS AND METHODS

Controlled temperature tissue welding of severed edges of fresh canine jejunum was performed in vitro by remote sensing of tissue surface temperature with an infrared sensor. A hardware controlled temperature feedback system opened and closed a shutter located in the beam path of an argon ion laser to provide constant temperature welding.

RESULTS

Strong tissue fusion was not possible at or below a surface temperature of 70 degrees C, but was accomplished at 80 degrees, 90 degrees, and 95 degrees, and 100 degrees C. Fusion was achieved with thermal coagulation of the collagenous submucosa and mucosal tissues. The bursting strength of welds created at 90 degrees C and 95 degrees C were significantly stronger than those performed at 80 degrees C.

CONCLUSION

Laser-assisted intestinal anastomoses created in vitro are optimally strong at 90-95 degrees C feedback control temperatures.

In vitro study of ablated lung tissue in Nd:YAG laser irradiation

BACKGROUND

Neodymium:yttrium-aluminum garnet lasers are used to reduce lung volume. An assessment of the relationship between the histologic and gross findings in the lung irradiated by a laser would be helpful in laser-assisted pneumoplastic procedures.

METHODS

In vitro lung lobes surgically resected for pulmonary carcinomas were irradiated with a neodymium:yttrium-aluminum garnet laser at three energy levels in three modes: contact rubbing, contact pointing, and noncontact. Pleural degeneration in 216 samples from 24 lobes was classified as coagulative, amorphous, or destructive. At all energy levels, the laser was applied for 1.5 seconds.

RESULTS

Noncontact mode at 7.5 W or 15 W and contact rubbing at 5 W caused coagulative or amorphous degeneration but no destructive degeneration. The energy level correlated with the color of the degenerated pleura. The incidence of destructive pleural degeneration, which led to air leaks as revealed by an air inflation test, was 0% in pink and white samples, 59% in brown samples, and 100% in black samples (p < 0.0001, white versus brown samples).

CONCLUSIONS

In neodymium:yttrium-aluminum garnet laser ablation of lung tissue, the color of the degenerated pleura correlates with the intensity of the applied laser energy and the degree of pleural degeneration.

Comparative study of abdominal incision techniques

The characteristics of surgical incisions made with an electrosurgical technique were compared with those made using conventional methods in a prospective randomized trial. In particular, the claim that the method of incision may influence postoperative pain was investigated. A total of 101 consecutive patients receiving full-length midline laparotomy incisions for gastrointestinal resection were studied. A record was kept of the time required to make the incision and blood loss as well as postoperative pain (using a linear analogue scale), ventilatory function and requirement for analgesia. There were 50 patients in group 1 (scalpel; 15 men, 35 women) and 51 in group 2 (electrocautery; 26 men, 25 women). The groups were similar in age, body-weight, diagnosis and the type of surgical procedures being performed. Incision time was similar in the two groups but median blood loss during incision was significantly less in group 2 patients than in group 1 (10 versus 25 ml, P < 0.0001). Linear analogue pain scores were not significantly different between the groups at any stage after operation. The same was true of postoperative ventilatory function and requirement for analgesia. A total value for morphine use during the entire postoperative period was derived for each group and the median was 1.55 mg/kg for group 1 compared with 1.49 mg/kg for group 2. The electrosurgical method is associated with less blood loss during incision, although this study has failed to confirm any reduction in postoperative pain or requirement for analgesia in these patients.

Sub ablation effects of the KTP laser on wound healing

The KTP laser (wavelength 532 nm) was used in a sub ablative format to determine the effect of low energy density irradiation on the normal healing by primary intention of scalpel skin incisions in rats. Two longitudinal lased strips were created by a 1 cm diameter defocused beam on the shaved, cleaned dorsal epidermis of 32 Sprague-Dawley rates; one strip was produced with a 2.0 W beam (54 J, or 18 J/cm2 total dose), and the other with a 3.5 W beam (94.5 J or 31.5 J/cm2, total dose). Scalpel incisions were made longitudinally within the irradiated zones, using contra lateral scalpel incisions on unirradiated skin as controls. Tensiometric analysis of wound strength was performed at 3, 7, 14, and 23 days following surgery. The data from fresh tissue tensiometry indicate that KTP laser irradiation of skin incisions results in a lower tensile strength for the wound at 7 and 14 days. The decrease in tensile strength is proportional to the total energy density of the exposure. At day 3 and 23, the tensile strength of the wound was independent of the sub ablative laser exposure. The results are in general agreement with studies of the healing process of laser incisions and may help us to understand the details of the healing process from laser incisions.

Laser-assisted intestinal anastomosis

Laser-assisted tissue fusion has been investigated as a new technology to enhance the healing of soft tissues. Laser fusion of intestinal anastomoses shows promise as a method to obtain primary healing while eliminating a foreign-body reaction associated with the sutures. This paper reviews the experimental data that are available regarding laser-assisted intestinal anastomoses and summarizes our experience using the CO2, Nd:YAG, and argon lasers to form fusions in small bowel.

Closure of rabbit ileum enterotomies with the argon and CO2 lasers: bursting pressures and histology

In this study, we examined short-term strength and histology of experimental argon and CO2 laser-welded and control-sutured enterotomies in a rabbit model. Longitudinal 1.0-cm enterotomies were closed with the argon laser at 0.5 (n = 10) or 1.0 (n = 10) W power and a spot diameter of 2.8 mm resulting in energy fluences of 230 and 450 J/cm2, respectively. Similar enterotomies were closed using the CO2 laser at 0.5 (n = 10) or 1.0 (n = 10) W power and a spot diameter of 1.2 mm, resulting in energy fluences of 1,360 and 2,730 J/cm2. In all closures, continuous wave laser was delivered for 30 seconds. Using a pressure-monitored infusion system with normal saline, the pressure required to burst each weld as well as sutured controls (n = 10) was recorded approximately 1 minute following fusion. Mean bursting pressures for the argon laser at 0.5 W and 1.0 W were 34.1 +/- 19.4 mm Hg (mean +/- SD) and 17.3 +/- 8.3 mm Hg, respectively, and for the CO2 laser were 23.5 +/- 12.0 mm Hg and 31.8 +/- 15.6 mm Hg, respectively. Sutured controls leaked at 45.2 +/- 12.0 mm Hg. With the exception of argon-laser welds at an energy fluence of 450 J/cm2, which were less than sutured repairs, the bursting pressures for welded closures were not significantly different from the sutured controls (Student's t distribution, P less than .05). Histologic examination of both types of welds demonstrated a fibrin and red blood cell coagulum bridging the anastomosis, with some evidence of mild thermal injury at the mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)