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Dive into the research topics where George Tzovaras is active.

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Featured researches published by George Tzovaras.


Endoscopy | 2008

A comparative study of standard ERCP catheter and hydrophilic guide wire in the selective cannulation of the common bile duct.

Panagiotis Katsinelos; George Paroutoglou; Jannis Kountouras; Grigoris Chatzimavroudis; Christos Zavos; Ioannis Pilpilidis; Tzelas G; George Tzovaras

BACKGROUND AND STUDY AIMS Deep cannulation of the common bile duct (CBD) is paramount for the success of endoscopic biliary intervention. The aim of the present study was to compare standard ERCP catheter and hydrophilic guide wire (HGW) in the selective cannulation of the CBD. PATIENTS AND METHODS A total of 332 patients were randomly assigned to cannulation with a standard catheter (n = 165) or a HGW (n = 167). If cannulation had not succeeded after 10 minutes with the technique assigned at randomization, a further attempt was made for an additional 10 minutes using the alternative technique. The following were assessed: primary and overall selective cannulation, time to cholangiography, number of pancreatic opacifications and guide-wire pancreatic duct insertions, and complication rates. RESULTS The primary success rate of selective CBD cannulation was higher in the HGW (81.4 %) than in the standard catheter group (53.9 %; P < 0.001). The overall cannulation rate after crossover was comparable between the two groups (standard catheter 84 % vs. HGW 83.8 %; P = 0.19). Time required for primary selective CBD cannulation was 3.53 +/- 0.32 minutes in the standard catheter vs. 4.48 +/- 0.32 minutes in the HGW group ( P = 0.04), and the number of insertions of the guide wire into the pancreatic duct was 3.29 +/- 0.47 in the standard catheter vs. 2.7 +/- 0.21 in the HGW group ( P = 0.22). Pancreatic opacifications occurred 3.19 +/- 0.20 times in the standard catheter vs. 1.50 +/- 0.22 times in the HGW group ( P < 0.001). Precut techniques were used in 56 patients (16.9 %) (n = 31 in the standard catheter vs. n = 25 in the HGW group; P = 0.07). The frequency of postinterventional pancreatitis and hemorrhage did not differ between the two groups. A young woman developed post-ERCP hemolytic crisis due to glucose-6-phosphate dehydrogenase deficiency. There was no procedure-related mortality. CONCLUSIONS The use of HGW, as primary technique or as a secondary technique after failure of cannulation with a standard catheter, achieves a high rate of selective CBD cannulation.


Diseases of The Colon & Rectum | 1996

Effect of nifedipine on rectoanal motility

Emmanuel Chrysos; Evaghelos Xynos; George Tzovaras; Odysseus John Zoras; John Tsiaoussis; Sophocles John Vassilakis

PURPOSE: Based on the rationale that the calcium channel blocker, nifedipine, decreases lower esophageal sphincter pressure in achalasia, a prospective controlled trial was performed to evaluate the effect of sublingual nifedipine on the anal sphincter of controls and patients with high anal resting pressures. METHODS: Ten age-matched and sex-matched controls without evidence of anal disorder and ten patients with hemorrhoids and/or fissure-in-ano were included in the study. Anorectal manometry, with an eight-channel, water-perfused catheter was performed on all patients before and 30 minutes after administration of 20 mg of sublingual nifedipine. RESULTS: Nifedipine significantly reduced anal resting pressure in both controls and patients by approximately 30 percent (P<0.001 andP<0.0001, respectively). A significant reduction was also noted in the length of high-pressure zone of the anal sphincter (P<0.02 for both groups) and in the frequency (controls,P<0.05; patients,P<0.03) and amplitude (controls,P<0.03; patients,P<0.009) of slow waves in both groups, whereas the presence, frequency, and amplitude of ultraslow waves were significantly reduced only in the patient group (P<0.05;P<0.01;P<0.0005, respectively). CONCLUSION: Nifedipine reduces the activity of the internal anal sphincter both in controls and patients with high anal resting pressure. The drug might be of some use in relieving symptoms in patients with hemorrhoids or anal fissure.


Obesity Surgery | 2011

Anatomy and Complications Following Laparoscopic Sleeve Gastrectomy: Radiological Evaluation and Imaging Pitfalls

George Triantafyllidis; Olga Lazoura; Eleni Sioka; George Tzovaras; Afroditi Antoniou; Katerina Vassiou; Dimitris Zacharoulis

BackgroundTo evaluate the post-operative gastric anatomy depicted by upper gastrointestinal gastrografin swallow studies (UGI) and report radiological work-up and management of complications following laparoscopic sleeve gastrectomy (LSG).MethodsThe study included 85 consecutive patients who underwent LSG for the treatment of morbid obesity. In all patients, a UGI was routinely performed on POD 3 to exclude early complications. In patients with suspected complications, further radiological evaluation with computed tomography (CT) was performed. The anatomy of the gastric remnant depicted by UGI was retrospectively evaluated in all patients.ResultsThe patterns of the gastric remnant identified were the tubular (65.9%), the superior pouch (25.9%), and the inferior pouch pattern (8.2%). Three patients had small superior pouches that resembled leaks, and the diagnosis was based on clinical symptoms. Post-operative complications were observed in 12.9% and included leaks (3.5%), hemorrhages (3.5%), strictures (2.3%), pulmonary embolism (1.2%), trocar site hernia (1.2%), and hematoma of the rectus abdominal muscle (1.2%). No mortality was noted.ConclusionsPost-operative radiological evaluation by UGI and CT is important for diagnosis and management of complications following LSG. Familiarity with the anatomy of the gastric remnant at UGI is essential for correct image interpretation.


Digestive Diseases and Sciences | 1995

Effect of Hiatal Hernia on Esophageal Manometry and pH-Metry in Gastroesophageal Reflux Disease

Panagiotis Kasapidis; John Sophocles Vassilakis; George Tzovaras; Emmanuel Chrysos; Evaghelos Xynos

An increased frequency of reflux events and a prolonged acid clearance have been shown in gastroesophageal reflux (GER) patients with a hiatal hernia as compared to those without. The objective of the present study was to further investigate esophageal motility and patterns of reflux in GER patients, in relation to the presence or absence of hiatal hernia. Esophageal manometry and ambulatory 24-hr esophageal pH-metry were used in 42 patients with GER and 18 controls. Eighteen of the patients were considered to have a nonreducing hiatal hernia on endoscopy. Hiatal hernia patients showed a higher extent of reflux (total composite score,P=0.016; total reflux time,P=0.008, reflux time in supine position,P=0.024; reflux time in upright position,P=0.008), a lower frequency of reflux events (P=0.005), a more severe esophagitis on endoscopy (P<0.01) and a lower amplitude of peristalsis at 5 cm proximal to LES (P=0.0009) as compared to patients without hiatal hernia. The amplitude of peristalsis at the distal esophagus was inversely related to the extent of reflux (P=0.024). Acid clearance was also significantly prolonged in the hernia subgroup (P=0.011). Although LES resting pressure did not differ significantly between the two subgroups of patients, it was inversely related to the extent of reflux in the patients with hiatal hernia (P=0.0005). It is concluded, that GER patients with hiatal hernia present with an increased amount of reflux and more severe esophagitis, which results in more severely impaired esophageal peristalsis as compared to patients without hernia. Prolonged acid clearance and impaired esophageal emptying observed in patients with hiatal hernia could be the result of both the presence of the hernia itself and the reduced peristaltic activity of the esophagus.


Surgical Endoscopy and Other Interventional Techniques | 2006

Laparoscopic cholecystectomy under spinal anesthesia : A pilot study

George Tzovaras; F. Fafoulakis; Konstantinos Pratsas; Stavroula Georgopoulou; Georgia Stamatiou; Constantine Hatzitheofilou

BackgroundRegional anesthesia has not been used as the sole anesthetic procedure other than in the scenario of a patient at high risk to undergo laparoscopic cholecystectomy with CO2 pneumoperitoneum under general anesthesia.MethodsFifteen ASA grade I or II patients underwent laparoscopic cholecystectomy with low-pressure CO2 pneumoperitoneum under spinal anesthesia. Intraoperative parameters, postoperative pain and recovery in general, as well as patient satisfaction at follow-up were prospectively recorded in a pilot study to assess the feasibility and safety of the procedure.ResultsAll operations were completed laparoscopically and conversion from spinal to general anesthesia was not required in any of the cases. Median pain score 4 h postoperatively was 1.5 (range, 0–5), at 8 h it was 1 (range, 0–6), and at 24 h it was 1 (range, 0–4). All patients were discharged after 24 h. Follow-up 2 weeks postoperatively showed all but one patient to be satisfied and strongly recommending the anesthetic procedure.ConclusionLaparoscopic cholecystectomy with low-pressure CO2 pneumoperitoneum can be successfully and safely performed under spinal anesthesia. Furthermore, it seems that spinal anesthesia is associated with minimal postoperative pain and at least an equally good recovery as with general anesthesia.


American Journal of Surgery | 2009

Is there a role for drain use in elective laparoscopic cholecystectomy? A controlled randomized trial

George Tzovaras; Paraskevi Liakou; Frank Fafoulakis; Ioannis Baloyiannis; Dimitris Zacharoulis; Constantine Hatzitheofilou

BACKGROUND Although the issue of drain use in open cholecystectomy has been adequately addressed by prospective randomized trials, there is lack of evidence on the usefulness of drains in elective laparoscopic cholecystectomy, and the surgeons follow their beliefs and bias on this debate. Therefore, a controlled randomized trial was designed to assess the value of drains in elective laparoscopic cholecystectomy. METHODS During a 5-year period (January 2002 to December 2006), 284 patients were randomized to have a drain placed (group A), whereas 281 patients were randomized not to have a drain (group B) placed in the subhepatic space. End points of this trial were to detect any differences in morbidity, postoperative pain, and hospital stay between the 2 groups. RESULTS There was no mortality in either group and no statistically significant difference in morbidity or hospital stay between the 2 groups. However, postoperative pain was significantly increased in patients who had a drain placed; median visual analog scale (VAS) score was 5 (range 1 to 8) versus 3 (range 1 to 8), in the non-drained group (P < .0001). Interestingly, in 2 of 3 patients in whom a drain was placed against randomization because of bile leak suspicion, a bile leak occurred. CONCLUSIONS The routine use of a drain in elective laparoscopic cholecystectomy has nothing to offer; in contrast, it is associated with increased pain. It would be reasonable, however, to leave a drain if there is a worry about an unsolved or potential bile leak, bearing in mind that drain placement, although sometimes providing a false sense of security, does not guarantee either prevention or treatment of postoperative bile collections, bleeding, or bile peritonitis.


Archives of Surgery | 2008

Spinal vs General Anesthesia for Laparoscopic Cholecystectomy: Interim Analysis of a Controlled Randomized Trial

George Tzovaras; Frank Fafoulakis; Kostantinos Pratsas; Stavroula Georgopoulou; Georgia Stamatiou; Constantine Hatzitheofilou

OBJECTIVE To compare spinal anesthesia with the gold standard general anesthesia for elective laparoscopic cholecystectomy in healthy patients. DESIGN Controlled randomized trial. SETTING University hospital. PATIENTS One hundred patients with symptomatic gallstone disease and American Society of Anesthesiologists status I or II were randomized to have laparoscopic cholecystectomy under spinal (n = 50) or general (n = 50) anesthesia. METHODS Intraoperative parameters, postoperative pain, complications, recovery, and patient satisfaction at follow-up were compared between the 2 groups. RESULTS All the procedures were completed by the allocated method of anesthesia, as there were no conversions from spinal to general anesthesia. Pain was significantly less at 4 hours (P < .001), 8 hours (P < .001), 12 hours (P < .001), and 24 hours (P = .02) after the procedure for the spinal anesthesia group compared with those who received general anesthesia. There was no difference between the 2 groups regarding complications, hospital stay, recovery, or degree of satisfaction at follow-up. CONCLUSIONS Spinal anesthesia is adequate and safe for laparoscopic cholecystectomy in otherwise healthy patients and offers better postoperative pain control than general anesthesia without limiting recovery.


Digestive Surgery | 2004

Early and Long-Term Results of Surgery for Severe Necrotising Pancreatitis

George Tzovaras; Rowan W. Parks; T. Diamond; B. J. Rowlands

Background: Necrotising pancreatitis is a challenging problem for the surgeon, as it is associated with considerable morbidity and mortality. The indications, timing of surgical intervention and type of procedure continue to be debated in an effort to improve the outcome of this devastating disease process. Methods: A retrospective analysis of early and long-term results in a series of 44 consecutive patients (34 men, 10 women, median age 46.5, range 13–74 years) who underwent necrosectomy for severe necrotising pancreatitis. In 16 patients necrosectomy and primary abdominal closure with drains was performed, 14 patients had planned staged necrosectomy and delayed abdominal closure with drains, and in 14 patients necrosectomy with open laparostomy was undertaken. Results: There were 8 deaths (18%) and 14 cases (32%) of significant hospital morbidity (fistula 10, pseudocyst 2, renal failure 2). Variables which correlated with mortality were: high APACHE II score, acute renal failure requiring dialysis, and requirement for surgical intervention at an early stage (within the first two weeks). A total of 28 late complications occurred in 21 of the surviving patients (endocrine pancreatic insufficiency 10, exocrine pancreatic insufficiency 2, pseudocyst 2, chronic renal failure 2, incisional hernia 10, recurrent pancreatitis 1, and chronic pain 1). Conclusions: Low mortality can be achieved in patients with severe necrotizing pancreatitis with aggressive surgical intervention and careful perioperative management. Long-term morbidity remains high, and emphasises the need for prolonged follow-up.


Obesity Surgery | 2012

Influence of the Learning Curve on Safety and Efficiency of Laparoscopic Sleeve Gastrectomy

Dimitris Zacharoulis; Eleni Sioka; Dimitris Papamargaritis; Olga Lazoura; Christos Rountas; Eleni Zachari; George Tzovaras

BackgroundLaparoscopic sleeve gastrectomy (LSG) is a relatively new bariatric procedure, and data regarding the learning curve are scarce. The aim of this study is to assess how the procedure can be safely implanted in a newly established bariatric unit and to define the learning curve.MethodsProctorship and mentorship in bariatric surgery were attended by two surgeons who were previously experienced in advanced laparoscopic surgery. The first consecutive 102 patients who underwent LSG in our newly established bariatric center were included. Patients were divided into three groups of 34 (groups 1, 2, and 3) according to case sequence. Data on demographics, operative time, conversion rate, hospital stay, morbidity, mortality, and excess weight loss (EWL) over time were compared between the groups.ResultsThe operative time was significantly lower in groups 2 (p = 0.016) and 3 (p = 0.003) compared to group 1. The learning curve was flat up to the 68th case. A significant decrease in hospital stay was noted for group 3 compared to groups 1 (p < 0.001) and 2 (p = 0.002). The conversion rate, mortality and morbidity rates, and EWL did not differ significantly between the groups. Mortality was 0.98% and procedure-related morbidity was 7.8%.ConclusionsLSG can be safely and efficiently performed in a newly established bariatric center following a mentorship procedure. Proficiency seems to require 68 cases. The operative time and hospital stay may significantly decrease with experience early in the learning curve, as opposed to mortality and morbidity rates, conversion rate, and EWL.


Surgery for Obesity and Related Diseases | 2013

Changes in gut hormone profile and glucose homeostasis after laparoscopic sleeve gastrectomy

Dimitris Papamargaritis; Carel W. le Roux; Eleni Sioka; George Koukoulis; George Tzovaras; Dimitris Zacharoulis

BACKGROUND Changes in glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) levels after bariatric surgery have been proposed as a mechanism for long-term maintenance of weight loss and improvement in glucose homeostasis postoperatively. The objective of the present study was to assess the changes in GLP-1, PYY, insulin, and glucose levels after laparoscopic sleeve gastrectomy (SG). METHODS Ten morbidly obese patients without type 2 diabetes (3 male, 7 female; body mass index [BMI] 47.92±2.06 kg/m(2)) were evaluated preoperatively and at 6 weeks, 6 months, and 12 months after SG. Total GLP-1, total PYY, insulin, and glucose were measured in fasting state and every 30 minutes after ingestion of 75 g glucose for a total time of 120 minutes. RESULTS BMI decreased markedly postoperatively (P<.001). Postprandial total GLP-1 and total PYY responses, measured by the area under the curve (AUC), were significantly increased by the sixth postoperative week compared with preoperative period (P<.001). Fasting insulin levels were markedly decreased postoperatively at all time points (all P<.01). Insulin AUC decreased progressively throughout the first postoperative year (P = .04), whereas glucose AUC decreased significantly at 6 and 12 months postoperatively (both P<.01). Insulin sensitivity measured by the Matsuda index increased progressively postoperatively. First phase insulin secretion remained unchanged. CONCLUSION Postprandial total GLP-1 and total PYY levels increased significantly at 6 weeks post-SG and remained elevated for at least 1 year. These findings may indicate their involvement in better glucose homeostasis and weight loss maintenance after SG.

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Eleni Sioka

University of Thessaly

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