hypersaline infusion protocol through the portal vein may focus electroporation on tumor tissue, but is it really safe? Ppreliminary results

Introduction: irreversible Electroporation (IRE) is highly dependent on the electrical conductivity of the tissue and the high conductivity of tumor tissue, which leads to a lower field than that in the surrounding healthy tissue. Hypersaline Infusion (HI) through the portal vein focuses IRE on scattered liver tumors, by creating a differential conductivity between the different types of tissue. The aim of this study is to determine the effects of the HI protocol on the hepatic and histological biochemical results. Methods: Ten male Sprague Dawley rats were used for HI protocol. Blood samples were collected at pre-, immediately post-, 24-hrs, 72-hrs, 1- week and 3-weeks post-HI. All the animals were sacrificed after a one-month follow-up in order to collect histological samples. Results: The mortality rate in this procedure reached 30% (3/10). Only the pH and transaminases at 24-hrs were significantly and directly linked to mortality (p=0.036 and p=0.004, respectively). The three non-surviving animals had a four-time higher AST level at 24-hrs. Natremianormalized at 24-hrs post-HI. Statistically significant differences were found in hepatic necrosis between the non-surviving (n=3) and surviving rats (n=7) (30.67 ± 10.97 vs. 2.86 ± 7.56% respectively, p=0.01). Discussion: HI through the portal system involves a significant risk of possibly lethal cytolysis and acidosis. Therefore, compensatory measures and a reduced saline overload are warranted to improve the survival rates

Feasibility study of an internally cooled bipolar applicator for RF coagulation of hepatic tissue: Experimental and computational study

Purpose: To study the capacity of an internally cooled radiofrequency (RF) bipolar applicator to create sufficiently deep thermal lesions in hepatic tissue. Materials and methods: Three complementary methodologies were employed to check the electrical and thermal behaviour of the applicator under test. The experimental studies were based on excised bovine (ex vivo study) and porcine liver (in vivo study) and the theoretical models were solved by means of the finite element method (FEM). Results: Experimental and computational results showed good agreement in terms of impedance progress and lesion depth (4 and 4.5 mm respectively for ex vivo conditions, and approximately 7 and 9 mm respectively for in vivo conditions), although the lesion widths were overestimated by the computer simulations. This could have been due to the method used to assess the thermal lesions; the experimental lesions were assessed by the white coagulation zone, whereas the tissue damage function was used to assess the computational lesions. Conclusions: The experimental results suggest that this applicator could create in vivo lesions to a depth of around 7mm. It was also observed that the thermal lesion is mainly confined to the area between both electrodes, which would allow lesion width to be controlled by selecting a specific applicator design. The comparison between the experimental and computational results suggests that the theoretical model could be usefully applied in further studies of the performance of this device. © 2012 Informa UK Ltd All rights reserved.This work received financial support from the Spanish Plan Nacional de I+D+I del Ministerio de Ciencia e Innovacion TEC2011-27133-C02-(01 and 02), from Universitat Politecnica de Valencia (INNOVA11-01-5502; and PAID-06-11 Ref. 1988). A. Gonzalez-Suarez is the recipient of grant VaLi+D (ACIF/2011/194) from the Generalitat Valenciana. The proof-reading of this paper was funded by the Universitat Politecnica de Valencia, Spain. The authors alone are responsible for the content and writing of the paper.González Suárez, A.; Trujillo Guillen, M.; Burdío Pinilla, F.; Andaluz Martínez, AM.; Berjano Zanón, E. (2012). Feasibility study of an internally cooled bipolar applicator for RF coagulation of hepatic tissue: Experimental and computational study. International Journal of Hyperthermia. 28(7):663-673. https://doi.org/10.3109/02656736.2012.716900S663673287Topp, S. A., McClurken, M., Lipson, D., Upadhya, G. A., Ritter, J. H., Linehan, D., & Strasberg, S. M. (2004). Saline-Linked Surface Radiofrequency Ablation. Annals of Surgery, 239(4), 518-527. doi:10.1097/01.sla.0000118927.83650.a4Gnerlich, J. L., Ritter, J. H., Linehan, D. C., Hawkins, W. G., & Strasberg, S. M. (2009). Saline-Linked Surface Radiofrequency Ablation. Annals of Surgery, 250(1), 96-102. doi:10.1097/sla.0b013e3181ae91afSakamoto, Y., Yamamoto, J., Kokudo, N., Seki, M., Kosuge, T., Yamaguchi, T., … Makuuchi, M. (2004). Bloodless liver resection using the Monopolar Floating Ball plus Ligasure diathermy: Preliminary results of 16 liver resections. World Journal of Surgery, 28(2), 166-172. doi:10.1007/s00268-003-7167-5Poon, R. T., Fan, S. T., & Wong, J. (2005). Liver resection using a saline-linked radiofrequency dissecting sealer for transection of the liver. Journal of the American College of Surgeons, 200(2), 308-313. doi:10.1016/j.jamcollsurg.2004.10.008EVERETT IV, T. H., LEE, K. W., WILSON, E. E., GUERRA, J. M., VAROSY, P. D., & OLGIN, J. E. (2008). Safety Profiles and Lesion Size of Different Radiofrequency Ablation Technologies: A Comparison of Large Tip, Open and Closed Irrigation Catheters. Journal of Cardiovascular Electrophysiology, 20(3), 325-335. doi:10.1111/j.1540-8167.2008.01305.xYokoyama, K., Nakagawa, H., Wittkampf, F. H. M., Pitha, J. V., Lazzara, R., & Jackman, W. M. (2006). Comparison of Electrode Cooling Between Internal and Open Irrigation in Radiofrequency Ablation Lesion Depth and Incidence of Thrombus and Steam Pop. Circulation, 113(1), 11-19. doi:10.1161/circulationaha.105.540062Demazumder, D., Mirotznik, M. S., & Schwartzman, D. (2001). Journal of Interventional Cardiac Electrophysiology, 5(4), 391-400. doi:10.1023/a:1013241927388Cooper, J. M., Sapp, J. L., Tedrow, U., Pellegrini, C. P., Robinson, D., Epstein, L. M., & Stevenson, W. G. (2004). Ablation with an internally irrigated radiofrequency catheter: Learning how to avoid steam pops. Heart Rhythm, 1(3), 329-333. doi:10.1016/j.hrthm.2004.04.019Burdío, F., Grande, L., Berjano, E., Martinez-Serrano, M., Poves, I., Burdío, J. M., … Güemes, A. (2010). A new single-instrument technique for parenchyma division and hemostasis in liver resection: a clinical feasibility study. 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Partial Laparoscopic Nephrectomy Using Monopolar Saline-Coupled Radiofrequency Device: Animal Model and Tissue Effect Characterization. Journal of Endourology, 19(4), 513-519. doi:10.1089/end.2005.19.513Voeller, R. K., Zierer, A., Lall, S. C., Sakamoto, S., Schuessler, R. B., & Damiano, R. J. (2010). Efficacy of a novel bipolar radiofrequency ablation device on the beating heart for atrial fibrillation ablation: A long-term porcine study. The Journal of Thoracic and Cardiovascular Surgery, 140(1), 203-208. doi:10.1016/j.jtcvs.2009.06.034Pai, M., Spalding, D., Jiao, L., & Habib, N. (2012). Use of Bipolar Radiofrequency in Parenchymal Transection of the Liver, Pancreas and Kidney. Digestive Surgery, 29(1), 43-47. doi:10.1159/000335732Berjano, E. J. (2006). BioMedical Engineering OnLine, 5(1), 24. doi:10.1186/1475-925x-5-24Tungjitkusolmun, S., Staelin, S. T., Haemmerich, D., Jang-Zern Tsai, Hong Cao, Webster, J. G., … Vorperian, V. R. (2002). 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Radiofrequency-assisted transection of the pancreas vs stapler in distal pancreatectomy: a propensity score matched cohort analysis

[EN] To demonstrate the efficacy of radiofrequency for pancreatic stump closure in reducing the incidence of postoperative pancreatic fistula (POPF) in distal pancreatectomy (DP) compared with mechanical transection methods. Despite all the different techniques of pancreatic stump closure proposed for DP, best practice for avoiding POPF remains an unresolved issue, with an incidence of up to 30% regardless of center volume or surgical expertise. DP was performed in a cohort of patients by applying radiofrequency to stump closure (RF Group) and compared with mechanical closure (Control Group). A propensity score (PS) matched cohort study was carried out to minimize bias from nonrandomized treatment assignment. Cohorts were matched by PS accounting for factors significantly associated with either undergoing RF transection or mechanical closure through logistic regression analysis. The primary end-point was the incidence of clinically relevant POPF (CR-POPF). Of 89 patients included in the whole cohort, 13 case patients from the RF-Group were 1:1 matched to 13 control patients. In both the first independent analysis of unmatched data and subsequent adjustment to the overall propensity score-matched cohort, a higher rate of CR-POPF in the Control Group compared with the RF-Group was detected (25.4% vs 5.3%, p = 0.049 and 53.8% vs 0%; p = 0.016 respectively). The RF Group showed better outcomes in terms of readmission rate (46.2% vs 0%, p = 0.031). No significant differences were observed in terms of mortality, major complications (30.8% vs 0%, p = 0.063) or length of hospital stay (5.7 vs 5.2 days, p = 0.89). Findings suggest that the RF-assisted technique is more efficacious in reducing CR-POPF than mechanical pancreatic stump closure.This work was supported completely by a grant for medical research from the Catalan Surgery Society. Project PI20/00008, funded by Instituto de Salud Carlos III (ISCIII) and co-funded by the European UnionPueyo-Périz, E.; Téllez-Marquès, C.; Radosevic, A.; Morató, O.; Visa, L.; Ilzarbe, L.; Berjano, E.... (2022). Radiofrequency-assisted transection of the pancreas vs stapler in distal pancreatectomy: a propensity score matched cohort analysis. Scientific Reports. 12(1):1-8. https://doi.org/10.1038/s41598-022-11583-01812