Michael Kontos

Comparison of Monopolar Electrocoagulation, Bipolar Electrocoagulation, Ultracision, and Ligasure

PurposeHemostasis is a fundamental principle of surgery. We compared the safety and efficacy of monopolar electrocoagulation (ME), bipolar electrocoagulation (BE), Ligasure (LS), a modern bipolar vessel sealing system, and Ultracision (UC), a system of ultrasound energy based shears. We also studied the healing process after their use.MethodsWe used each of the above methods to coagulate and divide the short gastric vessels of 16 white male New Zealand rabbits. The animals were killed after 3, 7, 14, or 21 days, and the coagulation sites and the adjacent gastric wall were examined histologically.ResultsLS and UC achieved complete hemostasis without any complications. Conversely, ME and BE often resulted in failed coagulation and perforation of the neighboring gastric wall from a side thermal injury. Histologically, LS demonstrated the mildest side thermal injury and the fastest healing process. We noted greater thermal injury and inflammatory response after UC than after LS on days 7 and 14; however, ME and BE caused the most severe lesions.ConclusionsLS and UC are clearly the safest and most efficient methods of coagulation, whereas ME and BE could cause serious clinical and histological complications. We found histological evidence that UC causes a slightly greater inflammatory response than LS, and the clinical implications of this warrant further investigation.

Comparison of safety and efficacy of ultrasonic and bipolar thermal energy: an experimental study.

The safety and efficacy of the Ligasure-8 Generator with the new Ligasure V 5-mm forceps (Valleylab, Tyco Healthcare) (LS) and the Ultracision Harmonic Scalpel Generator 300 with the new 5 mm 36p Harmonic Ace forceps (Ethicon Endo-Surgery ING) (UC) are compared. Twenty New Zealand rabbits were randomly allocated into 2 groups and the short gastric vessels were divided with either LS or UC. The speed of each method, the number of the times it had to be applied, gastric perforation rates and histopathologic findings were recorded. Approximately the same number of applications was necessary for the 2 groups. UC was significantly faster but resulted in contained perforation in 3 cases against 1 for LS (difference statistically not significant). A tendency for deeper and more severe histopathologic damages was seen with UC. For routine fast dissection, UC is satisfactory, but where prevention of thermal injury is important, LS may be more appropriate.

Impact of Graded Hypothermia on Coagulation and Fibrinolysis

BACKGROUND Hypothermia has a detrimental effect on hemostatic mechanism. The purpose of this experimental study was to investigate the effect of graded hypothermia on markers of the anticoagulant system (antithrombin III and protein C) and fibrinolytic system (plasminogen, α(2)-antiplasmin), and on vascular wall and other tissue specimens. MATERIALS AND METHODS Ten New Zealand rabbits were subjected to mild and then moderate core hypothermia of 32 °C for 60 min. Blood samples were obtained at normothermic (T(1)), mild (T(2)), and moderate (T(3)) hypothermic conditions. Chromogenic assay methods were used to determine quantitatively (%) the activity of antithrombin III, protein C, plasminogen, and α(2)-antiplasmin. Hypothermic values were compared with the normothermic values. Tissue and vessel wall specimens were examined under light microscope. RESULTS Reduction of activity (%) from normothermia (T(1)) to mild (T(2)) and moderate (T(3)) hypothermia was found for antithrombin III (103.40 ± 12.54, 87.40 ± 13.50, and 82.70 ± 20.78, respectively, with statistically significant difference between T(1)-T(3): P = 0.03), for protein C (70.1 ± 7.51, 56.30 ± 8.34, and 53.1 ± 7.34, with statistically significant difference between T(1)-T(2) and T(1)-T(3): P = 0.015 for both comparisons) and α(2)-antiplasmin (97 ± 9.63, 80.60 ± 11.73, and 83.70 ± 13.94, with statistically significant difference between T(1)-T(2): P = 0.006). Plasminogen activity was increased (14.50 ± 0.52, 16.30 ± 1.63, and 17.30 ± 2.45, with statistically significant difference between T(1)-T(2) and T(1)-T(3): P = 0.033 for both comparisons). Histologic examination revealed no significant lesions on tissue and vessel wall specimens. CONCLUSIONS The results of our study suggest that even though the hypothermia period was relatively short, the processes of coagulation and fibrinolysis were altered with simultaneous changes.

A novel spleen-preserving laparoscopic technique using radiofrequency ablation in a porcine model.

BackgroundPartial splenectomy is considered to be the optimal management for a variety of diseases. At the same time, laparoscopic procedures are increasingly used because they present certain advantages against their open counterparts. In this study, the safety and efficacy of radiofrequency ablation (RFA) were evaluated in laparoscopic partial splenectomy performed in a pig model.MethodsEight domestic pigs were used. Four abdominal trocars were inserted under general anesthesia and the spleen was stabilized with laparoscopic clamps. A RFA needle electrode was inserted transcutaneously, and coagulative necrosis of a zone of the splenic parenchyma between the body and the lower pole was performed. Bloodless sharp division and removal of the lower pole followed. After 0, 7, 30, or 120 days, the animals were killed and examined.ResultsBlood loss and operation time were minimal. Mortality and morbidity were zero. No abnormal findings were encountered during the postmortem abdominal exploration.ConclusionThis study demonstrates the feasibility, safety, and efficacy of laparoscopic RFA-assisted partial splenectomy. The RFA-assisted laparoscopic partial splenectomy adds a novel technique to the surgeon’s armamentarium for the preservation of a part of the spleen.

Radio frequency ablation (RFA)-assisted pericystectomy for hepatic echinococcosis: an alternative technique.

The aim of this study is to describe an alternative technique, using radio frequency energy to perform pericystectomy for hepatic echinococcosis. We present 3 patients with hepatic echinococcosis who were treated with radio frequency ablation (RFA)-assisted pericystectomy. A Radionics Cooltip Radio Frequency System (Tyco, Greece, Radionics) with a single shaft 15 cm long needle electrode and a 2 cm exposure tip, was used. The needle electrode was inserted in consecutive sites into the “healthy” hepatic parenchyma close to the cyst wall, so that a tissue zone around the cystic cavity was gradually ablated. The complete ablation of a site was followed by sharp division of the parenchyma. The operation completed successfully in all patients. Minor bleeding and/or bile leakage were successfully controlled with RFA coagulation. No other hemostatic method was used. The postoperative course was uneventful. No evidence of recurrent disease, or any other cause of morbidity, has been demonstrated at follow up (2 y). RFA-assisted pericystectomy for hepatic hydatid disease in experienced hands, might be useful to perform a “sterile” resection, eradicating single or multiple cysts and preventing local recurrence, with minimal morbidity.

Radiofrequency tissue ablation in an experimental model of grade IV renal trauma: a preliminary report

BackgroundThe kidney is one of the most frequently injured intraabdominal organs. In this study, we investigated the efficacy and safety of radiofrequency ablation (RFA) as a kidney-preserving hemostatic technique for grade IV renal trauma.MethodsA grade IV injury was induced in the right kidney of 12 Landrace pigs. Then RFA was applied around the injury in 10 animals until hemostasis was achieved; two animals were not treated (control group). The treated animals were killed humanely on days 0, 3, 7, 14 and 21 and examined. The kidneys were subjected to histologic and radiologic examination.ResultsThe two untreated animals died from hypovolemic shock. Hemostasis was achieved in all treated animals. We had no operative deaths and no morbidity. No blood, pus, urine, or other fluid was found at the time of death. In one animal, a fistulous lesion leading to the collecting system was identified, but no urine leakage was observed. At histology, the ablated areas were found to consist of three zones: an inner necrotic one, a zone of neutrophils digesting necrotic tissue, and an outer zone with possibly reversible damage.ConclusionsRadiofrequency ablation is an efficient and safe hemostatic method for grade IV renal trauma. Further study is needed to investigate the possible application of this method to humans and its percutaneous or laparoscopic use.

The Hepaticojejunostomy Technique with Intra-Anastomotic Stent in Biliary Diseases and Its Evolution throughout the Years: A Technical Analysis

Roux-en-Y hepaticojejunostomy (RYHJ) is currently considered as the definitive treatment for iatrogenic bile duct injuries and the principal representative of biliary diversion procedures. This technique has met many milestones of extensive evolution, particularly the last years of concomitant technological evolution (laparoscopic/robotic approach). Anastomotic strictures and leaks, which may have deleterious effects on the survival and quality of life of a patient with biliary obstruction of any cause, made the need of the development of a safe and efficient RYHJ compulsory. The aim of this technical analysis and the juxtaposed discussions is to elucidate with the most important milestones and technical tips and tricks all aspects of a feasible and reliable RYHJ technique that is performed in our center for the last 25 years in around 400 patients.

Gastric Collision Tumors: An Insight into Their Origin and Clinical Significance

Collision tumors are rare neoplasms displaying two distinct cell populations developing in juxtaposition to one another without areas of intermingling. They are rare entities with only 63 cases described in English literature. Tumors encountered are gastric adenocarcinomas colliding with lymphomas, gastrointestinal stromal tumors, squamous cell carcinomas, and neuroendocrine tumors. Their cell origin is obsolete by the time of diagnosis. Different tumorigenesis theories have been suggested to explain their behavior, yet none has managed to provide satisfactory explanation for all cases. Clinically they are indistinguishable from the dominant tumor. Lack of data does not allow detailed assessment of their behavior yet they seem aggressive neoplasms with dismal prognosis. The majority of cases have been diagnosed postoperatively during histologic examination of specimens. There are no guidelines or concrete evidence to support best way of adjuvant or other types of treatment. However, these rare neoplasms might help in unlocking secrets of cancer behavior including tumorigenesis, differentiation, and adhesion and thus clinicians should be aware of their existence.

The Greek financial crisis: maintaining medical education against the odds

Greece has been deeply affected by the severe financial crisis that struck the country in 2008, which resulted in government failure to reach financial targets, political instability and poor overall prospects. Higher education was particularly hit because it was seen as an easy target to reduce public expenditure and because it is heavily dependent on increasingly scarce government money. The National and Kapodistrian University of Athens (otherwise known as the University of Athens, UoA), which was founded in 1837, is the oldest institution of higher education in the country, and is closely connected with the history of modern Greece. The UoA School of Medicine (SoM), the largest and most sought after medical school nationally, current accepts about 4% of all applicants who take entry exams in their first undergraduate year. A freeze on recruitment, salary cuts, significant reductions in state contributions to institutional research funding and the failure of the government to meet its financial commitments to joint projects1 ,2 all impacted on the SoM. SoM employees were the first to be affected by the budget cuts. The numbers of workers employed were reduced through normal and early retirement combined with a freeze on hiring new staff, and their salaries were cut through the ‘availability’ measure, according to which civil servants—often administrative staff—are removed from their posts but remain ‘available’ for other posts in the public sector, while being paid a fraction of their salary. The annual state grant to cover the daily operational costs of the SoM was reduced by 71% between 2009 and 2014. Administrative staff are vital to the running of the SoM as procedures are generally …

Radiofrequency ablation-assisted liver resection: a step toward bloodless liver resection.

BACKGROUND Liver resection is currently the most efficient curative approach for a wide variety of liver tumors. The application of modern techniques and new surgical devices has improved operative outcomes. Radiofrequency ablation is used more often for liver parenchymal transection. This study aimed to assess the efficacy and safety of radiofrequency ablation-assisted liver resection. METHODS A retrospective study of 145 consecutive patients who underwent radiofrequency ablation-assisted liver resection was performed. Intraoperative blood loss, need for transfusion or intraoperative Pringle maneuver, the duration of liver parenchymal transection, perioperative complications, and postoperative morbidity and mortality were all evaluated. RESULTS Fifty minor and ninety-five major liver resections were performed. The mean intraoperative blood loss was 251 mL, with a transfusion rate of 11.7%. The Pringle maneuver was necessary in 12 patients (8.3%). The mean duration for parenchymal transection was 51.75 minutes. There were 47 patients (32.4%) with postoperative complications. There is no mortality within 30 days after surgery. CONCLUSIONS Radiofrequency ablation-assisted liver resection permits both major and minor liver resections with minimal blood loss and without occlusion of hepatic inflow. Furthermore it decreases the need for blood transfusion and reduces morbidity and mortality.