Functional Evaluation of a Novel Microwave Surgical Device in a Canine Splenectomy Model

Aim: Partial splenectomy remains a difficult procedure even with the assistance of a sealing system. Recently, a scissor-like microwave energy device (Acrosurg) that provides seamless coagulation and manual cutting has been applied in surgery. The objective of this study is to evaluate the surgical capabilities of Acrosurg in partial splenectomy. Materials and Methods: Acrosurg and Harmonic Focus (HF) were employed for partial splenectomy in dogs without prior ligation of vessels. Cutting time, cutting area, and bleeding were recorded. Lateral thermal injury (LTI), possible complications was observed immediately and after 4 weeks. Results: The manual cutting mechanism of Acrosurg required a longer cutting time compared with the automatic cutting mode of HF (301.5 [243.2-527] vs. 114.5 [106.0-135.0] sec, p < 0.01). There was no statistical difference in cutting area or bleeding cases. Acrosurg achieved complete hemostasis in all cases, whereas the HF group failed to stop bleeding in two of the eight cases. The Acrosurg group exhibited a similar LTI compared with the HF group (3.0 [2.4-3.4] vs. 2.7 [2.3-2.9] mm, p = 0.151), but the LTI of the Acrosurg group tended to shrink more after 4 weeks (1.2 [1.0-1.3] vs. 1.7 [1.3-1.9] mm, p < 0.05). Conclusions: A microwave energy device enabled a partial splenectomy without vessel ligation. The combination of manual cutting and sealing capability helps not only provide an appropriate seal time by adjusting cutting timing adaptively but also potentially stop bleeding by using a microwave heating process unlike other energy devices.

Precoagulation with microwave ablation for hepatic parenchymal transection during liver partial resection

PURPOSE

To evaluate the feasibility of precoagulation with microwave ablation (MWA) for hepatic parenchymal transection during liver partial resection.

METHODS

A total of 66 eligible patients were enrolled in this double-blind, randomized, controlled study. Patients were randomized to receive either the traditional clamp-crushing method (Control group) or the MWA precoagulation method (MWA group) for hepatic parenchymal transection during liver partial resection. The operative time, hepatic portal occlusion time, intraoperative blood loss and transfusion, postoperative complications and recovery outcomes were compared.

RESULTS

Compared to the Control group, the MWA group had significantly less intraoperative blood loss. Fewer red blood cell transfusions were observed in the MWA group but without statistical significance. The MWA group showed significantly higher serum alanine aminotransferase and aspartate aminotransferase levels at day 1 postoperatively, but no differences between the MWA and Control groups were found at days 3 and 7. There were no significant differences in terms of operative time, hepatic portal occlusion time, postoperative total bilirubin levels, human albumin solution consumption or length of hospital stay. Postoperative complications such as impaired renal function, pyrexia, admission to ICU, abscess, biliary leakage, intrahepatic and distant tumor recurrence and in-hospital mortality were comparable between the two groups.

CONCLUSION

Precoagulation with MWA reduced intraoperative blood loss with similar postoperative complications, providing a safe, effective, novel alternative for hepatic parenchymal transection during liver partial resection. Additional results from larger series are recommended to confirm these findings.

Experimental Nanopulse Ablation of Multiple Membrane Parasite on Ex Vivo Hydatid Cyst

The impact of ultrashort nanopulse on cellular membrane is of biological significance and thus has been studied intensively. Different from cell study, this ex vivo study aims to investigate the biological effects of nanosecond pulsed electric field (nsPEF) on an independent multimembrane parasite, human hydatid cyst, to observe the unique influence of nanopulse on macromembrane structure, permeabilization, and biochemistry. The 300 ns nsPEF was delivered on an experimental model of single human hydatid cyst ex vivo with eight different parameters. Then pathological changes during 7 days of 48 parasite cysts were followed up after nsPEF. The laminated layer, the germinal layer, the protoscolex, and cyst fluid were evaluated by the morphological, pathological, and biochemical measurements. The parameter screening found that nsPEF can damage hydatid cyst effectively when the field strength is higher than 14 kV/cm. When nsPEF is higher than 29 kV/cm, nsPEF destroy hydatid cyst completely by collapsing the germinal layer, destructing protoscolices, and exhausting the nutrition.

Evaluation of percutaneous microwave coagulation therapy for hepatic artery injury

Objectives

To evaluate the in vivo efficacy of 915 MHz percutaneous coagulation in the treatment of hepatic artery injury.

Methods

After inducing hepatic artery injury, 8 dogs in each group underwent 915 MHz microwave percutaneous coagulation therapy and 8 dogs were injected with batroxobin and α-cyanoacrylate.

Results

The hemostatic effects of 915 MHz microwave were better than drug injection, and the amount of bleeding was significantly lower (p < 0.05). Pathological examination showed that vessel wall necrosis were greater.

Conclusion

Contrast ultrasound guided 915 MHz microwave percutaneous coagulation treatment has potent hemostatic effects in the repair of in vivo hepatic artery injury.

Thermal tissue change induced by a microwave surgical instrument in a rat hepatectomy model

BACKGROUND

Microwaves exhibit great potential in tissue heating, which causes effective coagulation. Using this energy, we have developed the microwave coagulation surgical instrument (MWCX) for clinical application. Here, we characterized the impact of MWCX on tissues including heating property, tissue change, and spread of thermal injury.

METHODS

Hepatectomy was performed with MWCX using a rat model. The resections were completed using various energy levels and powers. Tissue temperature during radiation was recorded. Tissue change and lateral thermal injury (LTI) was assessed immediately, 7 days, 3 months, and 6 months after resection.

RESULTS

All cutting and hemostasis procedures were successfully accomplished. Major histologic findings consisted of deformation or destruction of hepatocytes, tissue edema, and peripheral hemorrhage. At various energy levels, 200 to 1000 J, the tissue was heated up to approximately 80°C to 140°C causing 2.7- to 6.5-mm LTI on the 7th day. LTI was then decreased gradually in the following term. At certain energy levels, the application of neither 20 W nor 40 W induced significant difference in both heating and LTI.

CONCLUSIONS

MWCX achieved effective tissue coagulation with relevant tissue injury, and it should be a good candidate for clinical application.