Bipolar radio-frequency-induced thermofusion of intestinal tissue –In vivoevaluation of a new fusion technique in an experimental study

Reduced Thermal Damage Achieved by High-Conductivity Hydrogel in RF Energy Tissue Welding

Radiofrequency (RF) tissue welding is an innovative tissue anastomosis technique that utilizes bioimpedance to convert electrical energy into thermal energy, enabling the connection and reconstruction of tissues via the denaturation and crosslinking of proteins. However, the high temperatures generated in this process often lead to excessive thermal damage to tissues, thereby adversely impacting cellular activity and impeding tissue repair in practical applications. In this study, we developed a polyacrylamide/alginate (PAAm/Alg) hydrogel with high ionic conductivity (16.8 ± 1.2 S/m) achieved by introducing Ca2+ for the purpose of reducing thermal damage in RF tissue welding. The PAAm/Alg-Ca2+0.5M hydrogel possessed excellent mechanical properties with a stress of 315.6 ± 14.1 kPa and an elongation of 382.7 ± 89.0%. Additionally, the hydrogel exhibited a high water content (83.7 ± 0.3%) and excellent stability of swelling property in water. In addition, the hydrogel extract showed good biocompatibility with no significant adverse effects on cell activity in the cytotoxicity test. At last, we conducted ex vivo experiments to investigate the effectiveness of the hydrogel as a cooling agent during RF tissue welding. The result showed that the maximum temperature was effectively reduced from 137.9 ± 4.7 to 101.8 ± 2.5 °C, while the strength of the anastomotic stoma (12.0 ± 3.2 kPa) was not affected by the intervention of this hydrogel. Histological analysis also revealed that the anastomotic structure of the tissue with hydrogel intervention was more intact than that of the control. Thus, the PAAm/Alg-Ca2+0.5M hydrogel has been demonstrated to function effectively as a cooling agent, offering a new strategy for thermal damage control in RF tissue welding.

Evaluation of intestinal wall closure using vessel-sealing technology versus conventional closure: an in vivo study

PURPOSE

Anastomotic leakage is a major postoperative complication of colorectal surgery. LigaSure™ is used commonly for vessel-sealing, but its use for intestinal anastomosis or closure, particularly the healing process, is underreported. We conducted this study to evaluate the feasibility of using LigaSure™ for intestinal wall closure, compared with hand-sewn methods.

METHODS

We performed intestinal wall closure of the cecum in rat laparotomy procedures, dividing subjects into a LigaSure™ group (LS) and a hand-sewn group (HS). We compared operation times, tissue structure changes, and pressure resistance from immediately post-operatively to postoperative day (POD) 14.

RESULTS

No postoperative dehiscence or mortality occurred in either group. The LS group required significantly less closure time (113 s) than the HS group (321 s, p < 0.001). The adhesion rates for a midline incision were not significantly different between the groups (LS: 26.7% vs. HS: 6.7%; p = 0.142), with adhesions at the closure site seen in all subjects. The LS group had a lower burst pressure than the HS group until POD 3, with no significant differences thereafter. Structural continuity was established by POD 5 in both groups.

CONCLUSIONS

LigaSure™ provides effective intestinal wall closure with a more distinct healing process than with hand-sewn methods, suggesting the potential for staple-free anastomosis.

Ex vivo comparison of leakage pressures and leakage location with a novel technique for creation of functional side-to-side canine small intestinal anastomoses

OBJECTIVE

To determine the ability of functional side-to-side small intestinal anastomoses (FSS-SIA) created with an electrothermal bipolar vessel sealing (EBVS) device to resist leakage.

STUDY DESIGN

Experimental, ex vivo.

SAMPLE POPULATION

Jejunal segments (n = 130) from 10 healthy canine cadavers.

METHODS

Four types of anastomoses were created (two segments/construct and 15 constructs/group): EBVS (group A), EBVS + transverse stapling (group B), stapled (group C), and EBVS + suture augmentation (group D). Initial leakage pressure (ILP), initial leakage location (ILL), and maximal intraluminal pressure were compared between groups, and five group A constructs were analyzed histologically.

RESULTS

Initial leakage pressure was greater in group D than in groups A, B, and C (P < .011). There was a difference in ILL among groups (P = .003). Leakage occurred at the side-to-side intestinal anastomosis fusion line in 13 of 15 (87%) constructs for groups A and B and in nine of 15 (60%) constructs for group D. Maximal intraluminal pressure was greater in group C than in groups A, B, and D (P < .004). Histological examination was consistent with collagenous fusion without cavitation defects.

CONCLUSION

Functional side-to-side small intestinal anastomosis was consistently achieved with an EBVS device. Augmentation of EBVS anastomoses with simple interrupted sutures along the anastomotic fusion line increased ILP compared with stapled anastomoses.

CLINICAL SIGNIFICANCE

Despite the success and feasibility of creating an FSS-SIA with an EBVS device, additional in vivo studies are required to determine the effectiveness of intestinal fusion prior to clinical implementation.