Low-voltage coagulation for welding sutures watertight: an experimental study

Assessing the influence of parameters on tissue welding in small bowel end-to-end anastomosis in vitro and in vivo

BACKGROUND

The use of high-frequency electric welding technology for intestinal end-to-end anastomosis holds significant promise. Past studies have focused on in vitro, and the safety and efficacy of this technology is uncertain, severely limiting the clinical application of this technology. This study investigates the impact of compression pressure, energy dosage, and duration on anastomotic quality using a homemade anastomosis device in both in vitro and in vivo settings.

METHODS

Two hundred eighty intestines and 5 experimental pigs were used for in vitro and in vivo experiments, respectively. The in vitro experiments were conducted to study the effects of initial pressure (50-400 kpa), voltage (40-60 V), and time (10-20 s) on burst pressure, breaking strength, thermal damage, and histopathological microstructure of the anastomosis. Optimal parameters were then inlaid into a homemade anastomosis and used for in vivo experiments to study the postoperative porcine survival rate and the pathological structure of the tissues at the anastomosis and the characteristics of the collagen fibers.

RESULTS

The anastomotic strength was highest when the compression pressure was 250 kPa, the voltage was 60 V, and the time was 15 s. The degree of thermal damage to the surrounding tissues was the lowest. The experimental pigs had no adverse reactions after the operation, and the survival rate was 100%. 30 days after the operation, the surgical site healed well, and the tissues at the anastomosis changed from immediate adhesions to permanent connections.

CONCLUSION

High-frequency electric welding technology has a certain degree of safety and effectiveness. It has the potential to replace the stapler anastomosis in future and become the next generation of new anastomosis device.

Colorectal anastomosis facilitated by the use of the LigaSure(®) sealing device: comparative study in an animal model

BACKGROUND

Recently, there has been speculation about the possibility of fusing intestinal tissue using bipolar sealing devices. In this study we compare in a porcine model the anastomoses created using the LigaSure(®) device with those created with a stapler after section and closure of a rectal stump.

METHODS

Thirty pigs underwent laparoscopic colorectal anastomosis. In group A (n = 15), the division of the intestine and distal stump closure were done with a 10-mm LigaSure Atlas(®) device. In group B, these steps were carried out using an endoscopic stapler. Subsequently, the colorectal anastomosis was performed using circular stapling in both groups. The 4-week follow-up included health status, weight gain, blood tests, X-rays, and colonoscopy. Anastomotic tissue was processed to study the mechanical tensile strength and histopathology.

RESULTS

There was no difference in the rate of conversion to open surgery or in average operating time between the groups. In the sealing device group, there was a significantly higher rate of failure in rectal stump closure (p = 0.042). There was one death in group B due to anastomotic leak. There was no difference in adhesion formation or stenosis. Mid-section anastomosis area was 89.7 mm(2) in group A compared with 100 mm(2) in group B (p = 0.52). In tensile strength studies, the maximum load resisted by the sample was 13.8 ± 4.9 N (group A) versus 15.7 ± 4.4 N (group B) (p = 0.17). There was no difference between the groups in degree of reepithelialization, number of inflammatory cells, or the presence of microabscesses.

CONCLUSIONS

Division and sealing of the rectal stump with the LigaSure(®) device is feasible in the proposed experimental model, but it is less reliable than conventional closure with a stapler, since it has a significantly greater failure rate. Therefore, The LigaSure(®) device should not be used for this purpose in the clinical setting as this could lead to serious and dramatic complications.

Bipolar radiofrequency-induced thermofusion of intestinal anastomoses--feasibility of a new anastomosis technique in porcine and rat colon

PURPOSE

In recent years, vessel sealing has become a well-established method in surgical practice for sealing and transecting vessels. Since this technology depends on the fusion of collagen fibers abundantly present in the intestinal wall, it should also be possible to create intestinal anastomoses by thermofusion. Bipolar radiofrequency-induced thermofusion of intestinal tissue may replace traditionally used staples or sutures in the future. The aim of this study was to evaluate the feasibility of fusing intestinal tissue ex vivo by bipolar radiofrequency-induced thermofusion.

MATERIALS AND METHODS

An experimental setup for temperature-controlled bipolar radiofrequency-induced thermofusion of porcine (n = 30) and rat (n = 18) intestinal tissue was developed. Colon samples were harvested and then anastomosed, altering compressive pressure to examine its influence on anastomotic bursting pressure during radiofrequency-induced anastomotic fusion. For comparison, mechanical stapler anastomoses of porcine colonic samples and conventional suturing of rat colonic samples identical to those used for fusion experiments were prepared, and burst pressure was measured.

RESULTS

All thermofused colonic anastomoses were primarily tight and leakage proof. For porcine colonic samples, an optimal interval of compressive pressure (1,125 mN/mm(2)) with respect to a high amount of burst pressure (41 mmHg) was detected. The mean bursting pressure for mechanical stapler anastomosis was 60.7 mmHg and did not differ from the thermofusion (p = 0.15). Furthermore, the mean bursting pressure for thermofusion of rat colonic samples was up to 69.5 mmHg for a compressive pressure of 140 mN/mm(2).

CONCLUSION

These results confirm the feasibility to create experimental intestinal anastomoses using bipolar radiofrequency-induced thermofusion. The stability of the induced thermofusion showed no differences when compared to that of conventional anastomoses. Bipolar radiofrequency-induced thermofusion of intestinal tissue represents an innovative approach for achieving gastrointestinal anastomoses.

Pilot study of bipolar radiofrequency-induced anastomotic thermofusion-exploration of therapy parameters ex vivo

PURPOSE

Vessel sealing has been well-established in surgical practice in recent years. Bipolar radiofrequency-induced thermofusion (BIRTH) of intestinal tissue might replace traditionally used staples or sutures in the near future. In this experimental study, the influence of compressive pressure, fusion temperature, and duration of heating on the quality of intestinal anastomosis was investigated to obtain the relevant major parameters for the in vivo use of this system.

METHODS

An experimental setup for a closed-loop temperature-controlled bipolar radiofrequency-induced thermofusion of porcine intestinal tissue was developed. Twenty-four colon samples were harvested from nine different Saalower-Kräuter pigs and then anastomosed altering compressive pressure on five different levels to explore its influence on anastomotic bursting pressure.

RESULTS

The anastomotic bursting strength depends on the compressive pressure applied to the colonic fusion site. An optimal interval of compressive pressure (CP = 1.125 N/mm(2)) in respect of a high amount of burst pressure was detected. A correlation (r = 0.54, p = 0.015) of burst pressure to delta compression indicated that increasing colonic wall thickness probably strengthens the anastomotic fusion.

CONCLUSION

This study is a first step to enlighten the major parameters of tissue fusion, though effects and interactions of various main parameters of bipolar radiofrequency-induced thermofusion of colonic tissue remain unclear. Further studies exploring the main effects and interactions of tissue and process parameters to the quality of the fusion site have to follow.