Monopolar electrosurgical thermal management for minimizing tissue damage

The research on the effect of temperature of electro-surgical unit to surgical smoke distribution in theatre-in vitro and simulation study

In electro-surgery, surgical smoke was hazard to surgeons and patient in theatre. In order to institute effective countermeasures, quantifying of the effect of tip temperature of electro-surgical unit to surgical smoke distribution in theatre was studied. The relation of tip temperature to power of electro-surgical unit through in vitro cutting experiment. Based on experiment data, the mathematical model was established to simulate the electro-surgery in laminar operation room. As the power of electro-surgical knife increased, the knife tip temperature increased. Total content of (CO, CO2, CH4, NH3) in waste gas and net flow rate of waste gas at outlet increased with the rising temperature of knife tip and formation rate of condensed tar droplets and non-viable particles also increased. Based on simulation, it was found that The maximum height of surgical smoke rising right above the incision of electro-surgical unit was increased with rising temperature of electro-surgical knife tip. There was a spread route of dispersed surgical smoke near the walls of theatre through natural convection. The polynomial fitting relationship was derived. As the tip temperature of knife increased from 200 to 500°C, maximum ascending height of surgical smoke right above the incision position of electro-surgical unit increased from 1.1 m to 1.45 m. When the tip temperature of electro-knife was more 400°C, the CO content in the surgeon's operating zone was more than 200 ppm, which would cause the surgeon's HbCO level increased. As the patient's tissue in the wound during operation was open, when the electro-knife of more than 400°C, the content of condensed tar droplets and in-viable particle was higher than 20 g/m3 and 12 g/m3 in the zone around patient's wound of open tissue, which should be hazard to health of patient.

Heat conduction in live tissue during radiofrequency electrosurgery

In this paper, we propose a method to model radiofrequency electrosurgery to capture the phenomena at higher temperatures and present the methods for parameter estimation. Experimental data taken from our surgical trials performed on in vivo porcine liver show that a non-Fourier Maxwell-Cattaneo-type model can be suitable for this application when used in combination with an Arrhenius-type model that approximates the energy dissipation in physical and chemical reactions. The resulting model structure has the advantage of higher accuracy than existing ones, while reducing the computation time required.

Synergetic Effects of Nanoscale ALD-HfO2 Coatings and Bionic Microstructures for Antiadhesive Surgical Electrodes: Improved Cutting Performance, Antibacterial Property, and Biocompatibility

The high temperature induced by surgical electrodes is highly susceptible to severe surface adhesion and thermal damage to adjacent tissues, which is a major challenge in improving the quality of electrosurgery. Herein, we reported a coupled electrode with micro/nano hierarchical structures fabricated by depositing nanoscale hafnium oxide (HfO2) coatings on bionic microstructures (BMs) via laser texturing, acid washing, and atomic layer deposition (ALD) techniques. The synergistic effect of HfO2 coatings and BMs greatly enhanced the hemophobicity of the electrode with a blood contact angle of 162.15 ± 3.16°. Furthermore, the coupled surface was proven to have excellent antiadhesive properties to blood when heated above 100 °C, and the underlying mechanism was discussed. Further experiments showed that the coupled electrode had significant advantages in reducing cutting forces, thermal damage, and tissue adhesion mass. Moreover, the antibacterial rates against Escherichia coli and Staphylococcus aureus were 97.2% and 97.9%, respectively. In addition, the noncytotoxicity levels of HfO2 coatings were verified by cell apoptosis and cycle assays, indirectly endowing the coupled electrode with biocompatibility. Overall, the coupled electrode was shown to have broad potential for application in the field of electrosurgery, and this work could provide new insights into antiadhesion properties under high-temperature conditions.

Use of Laparoscopic and Laparotomic J-Plasma Handpiece in Gynecological Malignancies: Results From A Pilot Study in A Tertiary Care Center

Introduction

The J-Plasma has recently been introduced into the surgical community with different intrinsic characteristics aimed to further reduce the thermal effect and enhance precision when compared to standard radiofrequency. This study aimed to investigate the role of this new technology in different conditions of gynecological carcinomatosis characterized by the indication for regional peritonectomy and/or ablation, either in laparotomy (LPT) or in laparoscopy (LPS), in the context of a modern personalized approach to the surgical management of gynecological malignancies.

Material and Methods

From January 2019 to April 2019, 12 patients were selected for this prospective pilot study at the Division of Gynecologic Oncology, Fondazione Policlinico Universitario A. Gemelli IRCCS in Rome. In this single surgeon experience, the inclusion criteria were: histologically proven advanced ovarian/endometrial cancer, primary or interval debulking surgery, and intraoperative indication for regional peritonectomy. Six patients were treated by LPS (Group 1) and 6 by LPT (Group 2).

Results

In Group 1 the indication for debulking surgery was in 4 cases an interval debulking surgery and 2 advanced endometrial cancer. All patients in Group 2 underwent primary debulking surgery for advanced ovarian cancer. The whole cohort achieved a complete tumor excision after surgery. The median OT and median EBL were 195 min and 100 ml in Group 1, and 420 min and 500 ml in Group 2. The median hospital stay was 4 days in Group 1 and 13 days in Group 2, respectively. No intra and postoperative complications were registered within 60 days after surgery.

Conclusions

J-Plasma allows to approach delicate maneuvers on viscera, mesentery, and blood vessels with a high degree of safety and precision thanks to its limited vertical and lateral thermal spread, favoring the surgeon to push ever higher the cytoreduction/morbidity tradeoff. The use of J-Plasma in cytoreductive surgery could also increase the range of possible minimally invasive procedures, narrowing the technical distance with the open technique and thus contributing to designing a personalized surgical strategy for each patient in different scenarios of peritoneal carcinomatosis.

Delayed bowel perforation after instilling over warmed peritoneal dialysate

BACKGROUND

Peritoneal dialysis (PD) is a safe and home-based treatment for end-stage renal disease (ESRD) patients. The direct thermal damage of abdominal organs is very rare.

CASE PRESENTATION

We report a peritoneal dialysis patient presented abdominal pain and feculent effluent 3 weeks after he instilled hot dialysis solution. In spite of emergency exploratory laparotomy and active treatment, the patient died of septic shock. Biopsy revealed necrosis and perforation of the intestines.

CONCLUSIONS

Delayed bowel perforation by hot fluid is very rare. Standardized performance is of the first importance for peritoneal dialysis patients.

A continuum thermomechanical model for the electrosurgery of soft hydrated tissues using a moving electrode

Electrosurgical radio-frequency heating of tissue is widely applied in minimally invasive surgical procedures to dissect tissue with simultaneous coagulation to obtain hemostasis. The tissue effect depends on the cumulative heating that occurs in the vicinity of the moving blade electrode. In this work, a continuum thermomechanical model based on mixture theory, which accounts for the multiphase nature of soft hydrated tissues and includes transport and evaporation losses, is used to capture the transient heating effect of a moving electrode. The model takes into account the dependence of electrical conductivity and the evaporation rate on the water content in the tissue, as it changes in response to heating. Temperature prediction is validated with mean experimental temperature measured during in situ experiments performed on porcine liver tissue at different power settings of the electrosurgical unit. The model is shown to closely capture the temperature variation in the tissue for three distinct scenarios; with no visible cutting or coagulation damage at a low 10 W power setting, with coagulation damage but no tissue cutting at an intermediate power setting of 25 W, and with both coagulation and tissue cutting at a higher power setting of 50 W. Furthermore, an Arrhenius model is shown to capture tissue damage observed in the experiments. Increase in applied power was found to correlate with tissue cutting and concentrated damage near the electrode, but had little effect on the observed coagulation damage width. The proposed model provides, for the first time, an accurate tool for predicting temperature rise and evolving damage resulting from a moving electrode in pure-cut electrosurgery.

Thermal effects of monopolar electrosurgery detected by real-time infrared thermography: an experimental appendectomy study

Background

Monopolar energy (ME) is routinely used in appendectomy. This study aimed to investigate the degree of lateral thermal spread generated by ME and to evaluate the thermal injury sustained by the close-lying tissues.

Methods

Appendectomy with a monopolar Maryland dissector was performed in 8 rabbits (at 30 and 60 W power settings). A high-resolution infrared camera was used to record tissue heating during the intervention. After autopsy macroscopic changes were evaluated and tissue samples were subjected to myeloperoxidase (MPO) assay and histological examination.

Results

No significant differences in the extent of thermal spread, MPO activity and histological signs of inflammation were observed between groups. Regardless of the power settings, the heat spread exceeded 2 cm laterally along the mesoappendix when application time exceeded 3 s. The spread of heat through tubular structures in both groups caused a significant temperature rise in the nearby intestinal loop, resulting in perforation (n = 3) and necrosis (n = 1).

Conclusions

Application time is critical in thermal spread during appendectomy aided by ME. Tubular anatomic structures can enhance thermal injury on distant tissues. The observed effects of ME bear clinical relevance that need further investigation.

Temperature monitoring for high frequency welding of soft biological tissues: A prospective study

BACKGROUND

Monitoring of temperature changes and accurately determining the moment of electrode removal during open heart operations is not well recognized.

OBJECTIVE

We investigated the temperature fields distribution in the biological tissues affected by electrosurgery upon use of an infrared thermograph.

METHODS

The dynamics of temperature distribution in the tissue was registered by the thermal imaging camera FLIR i7. Measurement of the temperature between electrode couples was carried out for two operation modes: coagulation (100% power) and coagulation (50% power).

RESULTS

The most important result of the applied method of temperature monitoring is a determination of the moment for electrodes removal that ensures the avoidance of carbonization of the cardiac tissues during their ablation.

CONCLUSIONS

Temperature monitoring for connection of soft live biological tissues by welding allows the power to be fed in the amount sufficient for a formation of continuous ablation of the myocardium tissue.

A continuum thermomechanical model of in vivo electrosurgical heating of hydrated soft biological tissues

Radio-frequency (RF) heating of soft biological tissues during electrosurgical procedures is a fast process that involves phase change through evaporation and transport of intra- and extra-cellular water, and where variations in physical properties with temperature and water content play significant role. Accurately predicting and capturing these effects would improve the modeling of temperature change in the tissue allowing the development of improved instrument design and better understanding of tissue damage and necrosis. Previous models based on the Pennes' bioheat model neglect both evaporation and transport or consider evaporation through numerical correlations, however, do not account for changes in physical properties due to mass transport or phase change, nor capture the pressure increase due to evaporation within the tissue. While a porous media approach can capture the effects of evaporation, transport, pressure and changes in physical properties, the model assumes free diffusion of liquid and gas without a careful examination of assumptions on transport parameters in intact tissue resulting in significant under prediction of temperature. These different approaches have therefore been associated with errors in temperature prediction exceeding 20% when compared to experiments due to inaccuracies in capturing the effects of evaporation losses and transport. Here, we present a model of RF heating of hydrated soft tissue based on mixture theory where the multiphase nature of tissue is captured within a continuum thermomechanics framework, simultaneously considering the transport, deformation and phase change losses due to evaporation that occur during electrosurgical heating. The model predictions are validated against data obtained for in vivo ablation of porcine liver tissue at various power settings of the electrosurgical unit. The model is able to match the mean experimental temperature data with sharp gradients in the vicinity of the electrode during rapid low and high power ablation procedures with errors less than 7.9%. Additionally, the model is able to capture fast vaporization losses and the corresponding increase in pressure due to vapor buildup which have a significant effect on temperature prediction beyond 100 °C.

Effect of high-frequency electric field on the tissue sticking of minimally invasive electrosurgical devices

Generally minimally invasive surgery is performed using an endoscope and other instruments including electrosurgical units (ESUs), and the adhesion of tissue to electrodes is a major concern. The mechanism governing this tissue sticking, especially the influence of high-frequency electric field, is still unclear. In this study, the effect of high-frequency electric field on the tissue sticking upon electrodes was investigated. The electrosurgical cutting test was performed on ex vivo fresh porcine liver under blend mode using a monopolar ESU. A heat-adherence test without electric field was used as a control. For the control group, the electrode was heated and maintained at a certain temperature and directly in contact with porcine liver. Both sticking tissues obtained from these two tests are partially carbonized porcine liver tissue, but their microstructure and bonding with electrode are obviously different. The sticking tissue formed just under heat is composed of biggish nanoparticles of different sizes which are loosely aggregated and has a weak bonding with the electrode, while the sticking tissue from the electrosurgical cutting test consists of tightly packed fine nanoparticles of equable size as a result of thermo-electric coupling and has a strong bonding with the electrode. Obviously, high-frequency electric field plays an extremely important role in the formation of the sticking tissue. It is the thermo-electric coupling that underlies the function of minimally invasive electrosurgical devices, and the effect of high-frequency electric field cannot be ignored in the tissue sticking study and anti-sticking strategies.

Rare complication after totally extraperitoneal endoscopic inguinal hernia repair: Small bowel perforation without peritoneal disruption

We report a rare case of visceral injury after totally extraperitoneal endoscopic inguinal hernia repair. A 48-year-old man underwent needlescopic totally extraperitoneal repair of a direct inguinal hernia. Bleeding from a branch of the inferior epigastric vessels occurred at the beginning of the extraperitoneal dissection with a monopolar electrosurgical device. Hemostasis was prolonged. However, herniorrhaphy and mesh repair were successfully performed, and no peritoneal disruption or pneumoperitoneum was visible. The patient was discharged home on the next day. However, 30 h after this operation, he underwent diagnostic and operative laparoscopy because of acute abdominal pain. Ileal perforation was found and repaired, and pathological examination indicated cautery artifact. Thus, thermal damage to the ileum during the initial operation may have caused the bowel perforation. To the best of our knowledge, no other cases of bowel perforation after totally extraperitoneal repair without peritoneal disruption have been reported.

Energy Dissipation in Ex Vivo Porcine Liver During Electrosurgery

This paper explores energy dissipation in ex vivo liver tissue during radiofrequency current excitation with application in electrosurgery. Tissue surface temperature for monopolar electrode configuration is measured using infrared thermometry. The experimental results are fitted to a finite-element model for transient heat transfer taking into account energy storage and conduction in order to extract information about "apparent" specific heat, which encompasses storage and phase change. The average apparent specific heat determined for low temperatures is in agreement with published data. However, at temperatures approaching the boiling point of water, apparent specific heat increases by a factor of five, indicating that vaporization plays an important role in the energy dissipation through latent heat loss.