Tamar Vasilyev

Immediate tight sealing of skin incisions using an innovative temperature-controlled laser soldering device: in vivo study in porcine skin.

Background:A feedback temperature-controlled laser soldering system (TCLS) was used for bonding skin incisions on the backs of pigs. The study was aimed: 1) to characterize the optimal soldering parameters, and 2) to compare the immediate and long-term wound healing outcomes with other wound closure modalities. Materials and Methods:A TCLS was used to bond the approximated wound margins of skin incisions on porcine backs. The reparative outcomes were evaluated macroscopically, microscopically, and immunohistochemically. Results:The optimal soldering temperature was found to be 65°C and the operating time was significantly shorter than with suturing. The immediate tight sealing of the wound by the TCLS contributed to rapid, high quality wound healing in comparison to Dermabond or Histoacryl cyanoacrylate glues or standard suturing. Conclusions:TCLS of incisions in porcine skin has numerous advantages, including rapid procedure and high quality reparative outcomes, over the common standard wound closure procedures. Further studies with a variety of skin lesions are needed before advocating this technique for clinical use.

Laparoscopic laser soldering for repair of ureteropelvic junction obstruction in the porcine model.

BACKGROUND AND PURPOSE Laparoscopic pyeloplasty is used for the repair of ureteropelvic junction (UPJ) obstruction. Our objective was to introduce laser soldering to this procedure. MATERIALS AND METHODS We developed a system based on a CO2 laser, an infrared detector, and two infrared transmitting optical fibers to obtain temperature-controlled laser soldering of cuts in tissues. The system was used for laparoscopic soldering of incisions in the kidneys of pigs. RESULTS We carried out laparoscopic pyeloplasty successfully in a porcine model using fiberoptic laser soldering. Laparoscopic laser soldering was found to be faster than suturing. It was easier to use and provided watertight bonding. CONCLUSIONS This technique will be useful in pyeloplasty as well as other laparoscopic surgical procedures.

Temperature-controlled two-wavelength laser soldering of tissues.

Laser tissue soldering is a method for bonding of incisions in tissues. A biological solder is spread over the cut, laser radiation heats the solder and the underlying cut edges and the incision is bonded. This method offers many advantages over conventional techniques (e.g., sutures). Past researches have shown that laser soldering, using a single laser, does not provide sufficient strength for bonding of cuts in thick (>1 mm) tissues. This study introduces a novel method for laser soldering of thick tissues, under temperature control, using two lasers, emitting two different wavelengths.

In vivo laser soldering of incisions in juvenile pig skins using GaAs or CO2 lasers and a temperature control system

Two temperature controlled laser soldering systems were compared, one based on a GaAs laser and the other on a CO2 laser. Both systems were used for bonding full thickness incisions. Methods: 47% bovine serum albumin (BSA) solder was used in the CO2 laser soldering experiments. BSA with 1.8 mg/ml Indocyanine Green (ICG) was used for the GaAs soldering experiments. In both cases the solder was applied onto cuts created in juvenile pig skin and an infrared fiberoptic system was used to monitor and control different temperature and time settings. Differences in tensile strength and wound reparative parameters were compared between GaAs laser, CO2 laser, and Dermabond glued incisions on the seventh day after the operation. Results: The tensile strength of CO2 laser-soldered and Dermabond glued incisions were found to be higher than that of the GaAs laser-soldered incisions. Histological study showed better and faster wound healing characteristics of the CO2 laser soldered incisions, as compared to the GaAs laser-soldered and glued incisions. Conclusions: Preliminary results of temperature controlled CO2 laser soldered incisions suggest a better wound reparative process over the temperature controlled GaAs laser soldered incisions. Laser soldering offers many advantages over gluing techniques.

CO 2 laser soldering of arteriotomy incisions in blood vessels of rats using a temperature-controlled fiber optic system

Background and objectives: Conventional methods for microvascular anastomosis are normally based on suturing, using special thin nylon sutures. These methods suffer from major drawbacks, which include: anastomosis, which is not watertight, and sutures or clips that cause an inflammatory response. In order to obtain better results, we introduced a procedure based on CO 2 laser soldering. We tested the system on arteriotomy incisions in rat blood vessels, in vivo. Materials and methods: We used a fiber optic based laser soldering system, with a temperature control capability. Arteriotomy incisions of lengths 4±1mm were performed on the femoral arteries of 48 wistar rats: 24 rats in the control group (suture) and 24 rats in the test group (laser soldering). We conducted two follow-up periods: 7 days and 21 days after the surgical procedure, for each group. Flow tests and histology examination were done in order to evaluate the quality of the procedures. Results: The patency rate was 84% for both groups, soldered and sutured. The sutured group showed a significant foreign body reaction (p < 0.05), which was not observed in the soldered group. We found no evidence of thermal damage in the soldered blood vessels. Conclusions: We can conclude that laser soldering is a less traumatic procedure, compared with the conventional suturing technique. It is potentially a faster technique and easier to master.

Errata: Temperature-controlled laser-soldering system and its clinical application for bonding skin incisions.

Laser tissue soldering is a method of repairing incisions. It involves the application of a biological solder to the approximated edges of the incision and heating it with a laser beam. A pilot clinical study was carried out on 10 patients who underwent laparoscopic cholecystectomy. Of the four abdominal incisions in each patient, two were sutured and two were laser soldered. Cicatrization, esthetical appearance, degree of pain, and pruritus in the incisions were examined on postoperative days 1, 7, and 30. The soldered wounds were watertight and healed well, with no discharge from these wounds or infection. The total closure time was equal in both methods, but the net soldering time was much shorter than suturing. There was no difference between the two types of wound closure with respect to the pain and pruritus on a follow-up of one month. Esthetically, the soldered incisions were estimated as good as the sutured ones. The present study confirmed that temperature-controlled laser soldering of human skin incisions is clinically feasible, and the results obtained were at least equivalent to those of standard suturing.

CO 2 temperature-controlled laser soldering of pig trachea incisions in vitro using flexible albumin bands

Resection of a segment of the trachea is a procedure applied for the removal of cervical tumors invading the trachea, or for the treatment of severe tracheal stenosis. The current method of anastomosis is based on multiple sutures. The main drawbacks of this method are: 1) A long procedure time, 2) An air leakage, and 3) An inflammatory response to the sutures. In this study we evaluated the feasibility and effectiveness of the use of temperature controlled CO2 laser soldering of incisions in pig tracheas in vitro. A transverse incision was made in a separated pig trachea. A flexible albumin band was prepared and was laser soldered with albumin solder to the outer surface of the trachea, covering the incision. The soldered trachea ends were sealed and the burst pressure was measured. In a series of in vitro experiments, the mean burst pressure was found to be 230 mm Hg. These preliminary results demonstrated that laser soldering using a flexible albumin band may be a useful method for sealing an incision in the trachea.

R174: CO2 Laser Soldering vs. Fibrin Glue for Dural Defect Repair

the back of 12 New Zealand white rabbits. Prior to suture closure, APG was placed in the wound bed on one side, while the other served as a control. Punch biopsies from each flap were obtained at 1-, 2-, and 3-week intervals and examined by an independent pathologist. RESULTS: Gross evaluation revealed decreased bleeding from the APG flaps at the time of biopsy. Wound contracture was noted in APG flaps at week 2, but no significant difference was observed by week 3. Histologic analysis revealed a trend towards increased acute inflammation in the APG sides at week 2. APG wounds also demonstrated increases in eosinophils within the subdermal layer and mast cells throughout the field. No significant differences were observed in the degree of fibrosis or collagen deposition between the two sides. CONCLUSION: In a rabbit skin flap model, APG affected gross appearance of the flap and influenced the biology of wound healing. SIGNIFICANCE: A variety of biomaterials have been applied in facial plastic and reconstructive surgery, and a common misperception is that autologous agents are relatively inert. The observations here demonstrate a definite effect of APG on the healing process. SUPPORT: 1.Sammy Sanders Research Fund, University of Tennessee 2.Delta Perfusion, LLC.

ICG-dyed albumin and diode laser heating for soldering of the trachea

Laser tissue soldering is a technique for the closure of incisions, which provides an immediate air- and watertight bond. Previous studies have shown that this method can bond tracheal incisions with the aid of stay sutures or solid albumin strips. In this study we investigated whether soldering using a diode laser and indocyanine green (ICG) dyed liquid albumin solution as solder, was efficacious for the repair of tracheal incisions without the need for additional strengthening aids. A transverse incision was made in isolated pig tracheas. The incision was smeared with liquid solder composed of 42% bovine albumin and 0.1 mg/ml ICG, and soldered using a temperature-controlled fiberoptic diode laser system. The soldered tracheal ends were sealed and the burst pressure measured. In a series of experiments the burst pressure was found to be higher than 382 mm Hg. These preliminary results demonstrate that diode laser tissue soldering of tracheal incisions provides better results than with a CO2 laser, and that it is possible to achieve considerable soldering strength without the use of any additional strengthening procedures.

Dural reconstruction by fascia using a temperature-controlled CO2 laser soldering system

Conventional methods for dura repair are normally based on sutures or stitches. These methods have several disadvantages: (1) The dura is often brittle, and the standard procedures are difficult and time consuming. (2) The seal is leaky. (3) The introduction of a foreign body (e.g. sutures) may cause an inflammatory response. In order to overcome these difficulties we used a temperature controlled fiber optic based CO2 laser soldering system. In a set of in vitro experiments we generated a hole of diameter 10 mm in the dura of a pig corpse, covered the hole with a segment of fascia, and soldered the fascia to the edges of the hole, using 47% bovine albumin as a solder. The soldering was carried out spot by spot, and each spot was heated to 65° C for 3-6 seconds. The soldered dura was removed and the burst pressure of the soldered patch was measured. The average value for microscopic muscular side soldering was 194 mm Hg. This is much higher than the maximal physiological pressure of the CSF fluid in the brain, which is 15 mm Hg. In a set of in vivo experiments, fascia patches were soldered on holes in five farm pigs. The long term results of these experiments were very promising. In conclusion, we have developed an advanced technique for dural reconstruction, which will find important clinical applications.