Lateral spread of heat during thyroidectomy using different haemostatic devices.

INTRODUCTION: The presented study is an attempt to comprehensively analyze the lateral spread of heat during thyroidectomy. Obtained results may be valuable in other surgical disciplines in which thermal analysis is difficult or impossible. OBJECTIVE: The aim of the study was to evaluate the temperature distribution in the operating field during thyroidectomy performed with the use of modern haemostatic instruments, and to define the safety margin for the investigated devices. MATERIALS AND METHODS: Ninety-three patients were thyroidectomised due to thyroid neoplasm. During all the operations the thermovisual measurements were carried out along with continuous intraoperative neuromonitoring of the recurrent laryngeal nerve (CIONM). Investigated patients were divided into 5 groups, named according to the applied haemostatic technique: LigaSure (N=17); ThermoStapler (N=20); Focus (N=19); SonoSurg (N=17) and Monopolar (N=20). RESULTS: At maximal performance settings, the highest working temperature was observed for the ThermoStapler, while the lowest temperature was recorded for the Monopolar. Safety margin and working time were increased in Focus and SonoSurg, compared to LigaSure and ThermoStapler. The differences in the necrosis thickness were negligible. The largest distance of the midline of the active blade from isotherm of 42ºC observed in the study was 5.51 mm; none of investigated devices used at a bigger distance had influence on the morphology of the electric signal of CIONM. CONCLUSION: The thermo-visual camera allows non-invasive, safe, and real-time monitoring and analysis of temperature distribution in the operation area during thyroidectomy. Proposed minimal safety margin for the analysed devices is 5.51 mm.

Effect of anode/filter combination on average glandular dose in mammography.

A comparative analysis of the mean glandular doses was conducted in 100 female patients who underwent screening mammography in 2011 and 2013. Siemens Mammomat Novation with the application of the W/Rh anode/filter combination was used in 2011, whereas in 2013 anode/filter combination was Mo/Mo or Mo/Rh. The functioning of mammography was checked and the effectiveness of the automatic exposure control (AEC) system was verified by measuring compensation of changes in the phantom thickness and measuring tube voltage. On the base of exposure parameters, an average glandular dose for each of 100 female patients was estimated. The images obtained by using AEC system had the acceptable threshold contrast visibility irrespective of the applied anode/filter combination. Mean glandular doses in the females, examined with the application of the W/Rh anode/filter combination, were on average 23.6% lower than that of the Mo/Mo or Mo/Rh anode/filter combinations. It is recommended to use a combination of the W/Rh anode /filter which exhibited lower mean glandular doses.

Comparison of lateral thermal spread using monopolar and bipolar diathermy, and the bipolar vessel sealing system ThermoStapler™ during thyroidectomy.

UNLABELLED: Electric devices enabling the maintenance of haemostasis during surgery have found application in modern thyroidectomy procedures. The haemostatic effect is associated with generation of heat, which apart from the intended result may bring about thermal tissue injury. The aim of the study was to determine the thermal spread around the active tip of electric devices in the operating field during total thyroidectomy, and the safe temperature range during the operation of studied devices. MATERIALS AND METHODS: Over 14 months from December 2009 until January 2011, 76 total thyroidectomy procedures were analysed. The surgeries employed mono- and bipolar diathermy as well as the ThermoStapler™ bipolar vessel sealing system. During the procedures, the thermal spread around the active tips of used electric devices was recorded with the use of high-definition camera. Comparable 5-second periods of electric device use at two power ranges (30 W and 50 W) were selected from the recorded material. The highest temperature of the active tip of electric devices was determined, and the 42°C isotherm was found with the use of computer image analysis, thus determining the safe distance of important anatomic structures from the active tip of the electric device. RESULTS: The temperature spread around the active tips of electric devices was recorded and the 42°C isotherm was determined. The diameter of this isotherm at the end of operation differed statistically significantly depending on the type of electric devices and power settings. The highest temperature, at both power ranges, was recorded for the bipolar vessel sealing system, while the lowest - for bipolar diathermy; at the same time a significantly lower 42°C isotherm diameter was found for ThermoStapler™ as compared with other devices. In all studied cases, the largest heat spread was found for monopolar diathermy. CONCLUSIONS: The mean safe distance of the active tip of an electric device from important anatomic structures is 5 mm and depends on the device type and its power settings. Monopolar diathermy causes the strongest heating of surrounding tissues, and the ThermoStapler™ bipolar vessel sealing system, despite producing the highest temperature during operation, causes relatively small thermal injury to the surrounding tissues.