Biomedical subjects

Lukas Krähenbühl

Publications and source records attributed to Lukas Krähenbühl.

11 recordsLinked to original sources

PubMed2006

Risk factors for perioperative complications in patients undergoing laparoscopic cholecystectomy: analysis of 22,953 consecutive cases from the Swiss Association of Laparoscopic and Thoracoscopic Surgery database.

BACKGROUND: Reliable risk factors for perioperative complications in patients undergoing laparoscopic cholecystectomy would be extremely useful to optimize the clinical management. This study aimed to determine risk factors that can be used for predicting perioperative complications. STUDY DESIGN: Possible risk factors for perioperative complications in patients undergoing laparoscopic cholecystectomy for acute and chronic cholecystitis were analyzed by a stepwise logistic regression model using data from the Swiss Association of Laparoscopic and Thoracoscopic Surgery (SALTS) database. RESULTS: A total of 22,953 patients with a mean (+/-SD) age of 54.5+/-16.1 years (range 17 to 89 years) and a male-to-female ratio of 1:2, underwent elective (85%) and emergency (15%) laparoscopic cholecystectomy. Multivariable analysis showed that male gender (odds ratio [OR]=1.16; p<0.0001), duration of intervention (OR=1.68 per 30 minutes; p<0.0001), body weight (>90 kg versus<60 kg; OR=1.34; p<0.0001), and the surgeon's own experience (>100 versus 11 to 100 interventions; OR=1.36; p<0.0002) were independently associated with an increased intraoperative local complication rate. In addition, male gender (OR=1.21; p<0.02), age (OR=1.12 per 10 years; p<0.0001), intraoperative complications (OR=2.1; p<0.0001), conversion to open surgery (OR=1.25; p<0.01), American Society of Anesthesiologists risk score (ASA score III/IV versus I/II: OR=1.28; p<0.0005), body weight (<60 kg versus>90 kg; OR=1.53; p<0.007), emergency surgery (OR=1.36; p<0.003), and duration of surgery (OR=1.28 per 30 minutes; p<0.0001) were found to be associated with a higher incidence of postoperative local complications. Higher postoperative systemic complications were encountered with conversion (OR=1.5; p<0.0002), ASA score (III/IV versus I/II: OR=1.54; p<0.0001), emergency surgery (OR=1.41; p<0.001), and a prolonged intervention time (OR=1.16 per 30 minutes; p<0.0001). CONCLUSIONS: For patients undergoing laparoscopic cholecystectomy (LC), the risk of possible perioperative complications can be estimated based on patient characteristics (gender, age, ASA score, body weight), clinical findings (acute versus chronic cholecystitis), and the surgeon's own clinical practice with LC. So in the likelihood of a case being a "difficult cholecystectomy," an experienced surgeon should be involved both in the decision-making process and during the operation. If LC lasts longer than 2 hours, the cumulative risk for perioperative complications is four times higher compared with an intervention that lasts between 30 and 60 minutes, independent of the surgeon's personal skills with LC.

Adolescent↗

PubMed2006

Laparoscopic surgery for benign lesions of the pancreas.

BACKGROUND: Minimally invasive pancreatic surgery, although known to be feasible and safe, is still not considered a standard procedure. We report our experience with laparoscopic pancreatic surgery in a retrospective case series. MATERIALS AND METHODS: Fifteen consecutive patients (3 male, 12 female) underwent primarily laparoscopic pancreatic surgery from February 2000 to June 2005. Histologically confirmed diagnoses were: neuroendocrine pancreatic tumors (n = 11), adult nesidioblastosis (n = 1), serous cystadenoma (n = 1), and pseudocysts due to chronic pancreatitis (n = 2). RESULTS: Enucleation (n = 3) or left pancreatic resection with spleen preservation (n = 6) was performed laparoscopically in 9 patients. The mean (+/-standard deviation) operative time was 173 +/- 48 minutes (range, 120-250 minutes) and the mean postoperative hospital stay was 5.5 +/- 1.2 days (range, 5-8 days) for the laparoscopic cases. Conversion to open surgery was necessary in 6 patients because of: closeness of the lesion to the portal/mesenteric vein (n = 3), inadequate intraoperative tumor localization (n = 2), or stapler device dysfunction (n = 1). In these patients, open enucleation (n = 1), middle segment pancreatectomy (n = 2), left pancreatic resection (n = 2), and pylorus-preserving Whipple resection (n = 1) were performed. The mean operative time was 268 +/- 74 minutes (range, 150-360 minutes) with a mean postoperative hospital stay of 8 +/- 2 days (range, 6-10 days). Both operative time and hospital stay were significantly longer in patients with secondary open surgery compared to patients with successful laparoscopic operations. CONCLUSION: Laparoscopic enucleation or distal pancreatectomy with spleen preservation for benign lesions located in the body or tail of the pancreas can be performed safely, with all the potential benefits of minimally invasive surgery. Preoperative tumor localization is of utmost importance to limit pancreatic mobilization and to avoid blind pancreatic resection and conversion to open surgery.

Adult↗

PubMed2005

Bleeding remains a major complication during laparoscopic surgery: analysis of the SALTS database.

BACKGROUND AND AIMS: The aim of this study was to determine the incidence of bleeding complications from various laparoscopic procedures in a nationwide prospective multicentre study in Switzerland from 1995 to 2001 following an initial learning curve. PATIENTS AND METHODS: Since 1989, the Swiss Association of Laparoscopic and Thoracoscopic Surgery (SALTS) has prospectively collected data from patients undergoing laparoscopic or thoracoscopic surgery at 114 surgical institutions (university, county and district hospitals, private practice). More than 130 items of data, including indication for surgery, intraoperative course, local as well as general postoperative complications, mortality and follow-up were recorded on a computerised data sheet. RESULTS: Some 43,028 procedures were assessed and analysed. Local morbidity (e.g. wound infections) occurred in 0.05% of the whole patient group, whereas 3.3% developed general postoperative complications. The overall mortality rate was 0.2%. In 1.7% of the cases, the intraoperative course was complicated by internal bleeding or haematoma of the abdominal wall. In the postoperative course, 1.5% of the patients presented with internal bleeding or bleeding of the abdominal wall. Major vascular injury occurred in 0.09%. This patient group with bleeding complications was analysed in the context of the operator's experience, instrumental lesions (Veress needle or trocar) and conversion incidence. Furthermore, a trend analysis of the complication rate from 1995 to 2001 was performed. CONCLUSION: Although the initial learning curve of laparoscopic procedures is probably finished, the rate of bleeding complications is still substantial. These results demonstrate that the collection of data in the form of multicentre studies is essential for quality control. It permits recognition and understanding of the current problems in laparoscopic surgery in order to improve the quality of daily surgical practice. The fact that the operator's experience seems to play an important role shows that improvement in learning and teaching programmes is still necessary and should be coordinated on a national basis.

Adolescent↗

PubMed2004

Selective arterial calcium stimulation and hepatic venous sampling in the evaluation of hyperinsulinemic hypoglycemia: potential and limitations.

PURPOSE: To describe the potential and limitations of selective arterial calcium stimulation and hepatic venous sampling (ASVS) in the evaluation of patients with hyperinsulinemic hypoglycemia. MATERIALS AND METHODS: Twenty-seven consecutive adult patients with documented hyperinsulinemic hypoglycemia undergoing an ASVS test and histologically confirmed diagnosis were included. RESULTS: By histology, 24 patients were found to have an insulinoma, two had islet cell hyperplasia, and one had insulin-secreting neuroendocrine carcinoma of the liver. ASVS correctly predicted the source of excessive insulin secretion in 26 of 27 (sensitivity, 96%) patients. In two patients with an insulinoma, ASVS had to be repeated for correct diagnosis; in one patient with a glucose-sensitive insulinoma, ASVS was falsely negative. In one patient, a falsely negative ASVS test was caused by diazoxide treatment; in another patient a falsely negative ASVS test occurred because of extraordinarily high baseline insulin levels when the calcium stimulation was performed. CT and/or MR imaging correctly predicted the source of excessive insulin secretion in 59% of patients, the sensitivity of the intraoperative exploration was 88%. CONCLUSIONS: In the authors' experience, the ASVS test is superior to CT/MR imaging and even the intraoperative exploration in identifying the source of excessive insulin secretion in patients with hyperinsulinemic hypoglycemia. To prevent false negative ASVS tests, medications with an influence on insulin secretion have to be discontinued prior to ASVS and two baseline blood samples should be obtained before the calcium stimulation is performed.

Adult↗

PubMed2003

Reduced hepatic glycogen stores in patients with liver cirrhosis.

BACKGROUND: Patients with alcoholic liver cirrhosis have reduced hepatic glycogen stores but the mechanisms leading to this finding are not clear. METHODS: We therefore determined the hepatic glycogen content in patients with alcoholic (n = 9) or biliary cirrhosis (n = 8), and in control patients undergoing liver surgery (n = 14). All patients were in the postabsorptive state. In addition, we performed a morphometric analysis of the livers, and measured activities and mRNA expression of several enzymes involved in glycogen metabolism. Cirrhotic and control patients were similar regarding age and body weight. RESULTS: Cirrhotic patients had a reduced glycogen content per gram liver wet weight (17 +/- 11 versus 45 +/- 17 mg/g, P < 0.05), per milliliter hepatocytes (28 +/- 16 versus 52 +/- 21 mg/ml, P < 0.05) and per liver (28 +/- 17 versus 64 +/- 22 g, P < 0.05), the reduction being observed in both patients with alcoholic or biliary cirrhosis. Liver histology confirmed these findings and revealed that the decrease in liver glycogen in cirrhotic patients was not homogeneous across cirrhotic lobules. Activities of glycogen synthase and phosphorylase (total activity and active form) were not different between cirrhotic and control patients, whereas hepatic mRNA expression was decreased in cirrhotics by approximately 50%. The activity of glucokinase was decreased in cirrhotic as compared in control patients (0.06 +/- 0.30 versus 0.42 +/- 0.21 U/ml hepatocytes, P < 0.05), the reduction being observed in both patients with alcoholic or biliary cirrhosis. CONCLUSIONS: We conclude that patients with alcoholic or biliary cirrhosis have decreased hepatic glycogen stores per volume of hepatocytes and per liver. Decreased activity of glucokinase may represent an important mechanism leading to this finding.

3-Hydroxybutyric Acid↗

PubMed2002

Liver surgery in the era of tissue-preserving resections: early and late outcome in patients with primary and secondary hepatic tumors.

During recent decades, the understanding of the segmental-oriented liver anatomy has enabled development of resection of isolated liver segments or sectors as dictated by the localization and extent of the mass lesion. These newer surgical procedures provide the advantage of maximal preservation of functional parenchyma, therefore minimizing the occurrence of postoperative liver failure and, at the same time, expanding the indications for surgery. We analyzed the results after classical hemihepatectomies and segment-based resections in a consecutive, nonselected patient group. During the 7-year period between November 1993 and November 2000, 270 patients with primary or secondary liver tumors were treated in our hospital; 167 of these patients underwent curative resections and their relevant data were entered into a statistical database. There were 77 classical hemihepatectomies and 90 tissue-preserving resections. Total mortality and morbidity for the series was 3.6% and 29.9%, respectively. Morbidity but not mortality was significantly lower after tissue-preserving resections than after classical hemihepatectomy. Median follow-up was 36 months. Survival was comparable for the two different surgical approaches for patients with secondary liver malignancies. In contrast, patients with hepatocellular carcinomas lived significantly longer after tissue-preserving resections. Tissue-preserving liver resection is a safe technique allowing maximal preservation of functional parenchyma without compromising radicality. Therefore, tissue-preserving resection is especially useful for patients with hepatocellular carcinomas and cirrhosis.

Adolescent↗

PubMed2002

Impact of laparoscopic and conventional surgery on Kupffer cells, tumor-associated CD44 expression, and intrahepatic tumor spread.

BACKGROUND: The oncologic feasibility of laparoscopic surgery for the cure of colorectal cancer is under debate. The effect of laparoscopic colorectal cancer resection on hepatic tumor spread has not yet been clarified. HYPOTHESIS: Laparoscopic surgery affects cell-mediated immune response and hepatic tumor spread dependent on intraperitoneal insufflation. METHODS: Thirty WAG/Rij rats were randomized into 3 operative groups: carbon dioxide (CO( 2)) laparoscopy (n = 10), "gasless" laparoscopy (n = 10), and laparotomy (n = 10). To induce liver metastases, 50 000 CC531 colon carcinoma cells were injected into the portal vein during either laparoscopy or laparotomy. Twenty-eight days after injection, specimens were explanted, sectioned, and examined immunohistochemically for CC531 tumor cells (monoclonal antibody CC52), CD44v5, v6 (monoclonal antibody OX49), and Kupffer cells (monoclonal antibody HIS36). For quantification, a morphometric analysis system was applied. Data were analyzed using the Kruskal-Wallis, Dunn, and Holm tests. RESULTS: No statistically significant differences in hepatic tumor growth were found between CO(2) laparoscopy and laparotomy (P =.37). However, compared with CO(2) laparoscopy and laparotomy, a significant decrease in intrahepatic tumor growth was found after gasless laparoscopy (P =.02). Kupffer cells had significantly decreased after CO(2) laparoscopy and laparotomy compared with after gasless laparoscopy (P<.001 and P =.002, respectively). CD44v5, v6 expression was significantly increased after CO(2) laparoscopy and laparotomy compared with after gasless laparoscopy (P =.002 and P =.05, respectively). CONCLUSIONS: Hepatic resistance to tumor growth is best preserved by gasless laparoscopy as opposed to CO(2) laparoscopy or laparotomy. The amount of intra-abdominal pressure with circulatory changes rather than the used gas may explain this finding. On the other hand, conventional laparoscopy vs laparotomy did not preserve hepatic immune function.

Animals↗

PubMed2002

Hepatic and skeletal muscle glycogen metabolism in rats with short-term cholestasis.

BACKGROUND/AIMS: To study the effect of short-term cholestasis on glycogen metabolism. METHODS: Rats were bile duct ligated (BDL) for 4 or 8 days and compared to sham-operated control rats pair-fed to BDL (pair-fed CON) or fed ad libitum (ad libitum-fed CON). RESULTS: Four days after surgery, the hepatic glycogen content was 21.6+/-7.6 mg/g in BDL, 21.2+/-8.5 mg/g in pair-fed CON and 72.9+/-7.7 mg/g in ad libitum-fed CON, respectively. Eight days after surgery, the hepatic glycogen content was reduced in BDL as compared to pair-fed (31.2+/-8.9 vs. 59.1+/-5.4 mg/g) or ad libitum-fed CON (58.3+/-4.7 mg/g). Similar findings were obtained with the glycogen content expressed per ml hepatocytes or per liver. Histological analysis of BDL livers showed that most hepatocytes were affected. As compared to CON, activities and mRNA levels of glycogen synthase and phosphorylase were reduced in BDL, whereas plasma glucagon and endotoxin levels were increased at both time points. In contrast to liver, skeletal muscle glycogen metabolism remained unaffected. CONCLUSIONS: While reduced intake of food explains the decrease in the hepatic glycogen stores in BDL and pair-fed CON 4 days after surgery, reduced glycogen synthesis, possibly related to endotoxinemia, is the most probable cause of the decrease in the hepatic glycogen content in BDL 8 days after surgery.

Acute Disease↗

PubMed2002

Impaired ketogenesis is a major mechanism for disturbed hepatic fatty acid metabolism in rats with long-term cholestasis and after relief of biliary obstruction.

BACKGROUND/AIMS: Rats with long-term cholestasis have reduced ketosis of unknown origin. METHODS: Fatty acid metabolism was studied in starved rats with biliary obstruction for 4 weeks (bile duct ligated rats = BDL rats), and 3, 7, 14, 28 and 84 days after reversal of biliary obstruction by Roux-en-Y anastomosis (RY rats), and in sham-operated control rats. RESULTS: BDL rats had reduced beta-hydroxybutyrate concentrations in plasma (0.25 +/- 0.10 vs. 0.75 +/- 0.20 mmol/l) and liver (2.57 +/- 0.20 vs. 4.63 +/- 0.61 micromol/g) which increased after restoring bile flow. Hepatic expression and activity of carnitine palmitoyltransferase I (CPT I) or CPT II were unaffected or decreased in BDL rats, respectively, and increased after restoring bile flow. Oxidative metabolism of different substrates by isolated liver mitochondria and activation of palmitate were reduced in BDL rats and recovered 7-14 days after restoring bile flow. Ketogenesis was decreased in mitochondria from BDL rats and recovered 3 months after restoring bile flow. Both mRNA and protein expression of hydroxymethylglutaryl-coenzyme A synthase (HMG-CoA synthase), the rate-limiting enzyme of ketogenesis, was reduced in livers of BDL rats and increased after reversing biliary obstruction. CONCLUSIONS: In BDL rats, impairment of hepatic fatty acid metabolism is multifactorial. After reversing biliary obstruction, reduced activity of HMG-CoA synthase is the major factor.

Anastomosis, Roux-en-Y↗

PubMed2002

Training for advanced laparoscopic surgery.

OBJECTIVE: To evaluate the efficiency of training for advanced minimally-invasive surgery in rats. SETTING: Teaching hospital, Germany. SUBJECTS: 10 surgical residents with few laparoscopic training skills had two days laparoscopic microsurgical training using rats. INTERVENTIONS: Increasingly difficult procedures started using a rubber model, followed by 'open' and 'closed' rat models simulating laparoscopic conditions. MAIN OUTCOME MEASURES: The surgical skills of all participants were assessed before and after the laparoscopic training course by applying 5 defined tasks in a simulation trainer. As a control group, 8 surgical residents with the same amount of minimal-invasive training were tested after a 2-day interval. RESULTS: All participants of the laparoscopic training programme significantly improved their surgical skills for all 5 tasks (p < 0.05). In the control group only one of the 5 tasks was significantly improved after repetition. Participants of the complete training programme consistently improved their surgical skills significantly compared with the controls before and after repetition (p < 0.05). CONCLUSION: Surgical training in minimal-invasive techniques in the rat model is effective and reproducible especially to improve laparoscopic skills such as bimanual tissue handling, knot tying and microsurgical suturing.

Animals↗

PubMed2002

Preoperative galactose elimination capacity predicts complications and survival after hepatic resection.

OBJECTIVE: To analyze a single center's 6-year experience with 258 consecutive patients undergoing major hepatic resection for primary or secondary malignancy of the liver, and to examine the predictive value of preoperative liver function assessment. SUMMARY BACKGROUND DATA: Despite the substantial improvements in diagnostic and surgical techniques that have made liver surgery a safer procedure, careful patient selection remains mandatory to achieve good results in patients with hepatic tumors. METHODS: In this prospective study, 258 patients undergoing hepatic resection were enrolled: 111 for metastases, 78 for hepatocellular carcinoma (HCC), 21 for cholangiocellular carcinoma, and 48 for other primary hepatic tumors. One hundred fifty-eight patients underwent segment-oriented liver resection, including hemihepatectomies, and 100 had subsegmental resections. Thirty-two clinical and biochemical parameters were analyzed, including liver function assessment by the galactose elimination capacity (GEC) test, a measure of hepatic functional reserve, to predict postoperative (60-day) rates of death and complications and long-term survival. All variables were determined within 5 days before surgery. Data were subjected to univariate and multivariate analysis for two patient subgroups (HCC and non-HCC). The cutoffs for GEC in both groups were predefined. Long-term survival (>60 days) was subjected to Kaplan-Meier analysis and the Cox proportional hazard model. RESULTS: In the entire group of 258 patients, a GEC less than 6 mg/min/kg was the only preoperative biochemical parameter that predicted postoperative complications and death by univariate and stepwise regression analysis. A GEC of more than 6 mg/min/kg was also significantly associated with longer survival. This predictive value could also be shown in the subgroup of 180 patients with tumors other than HCC. In the subgroup of 78 patients with HCC, a GEC less than 4 mg/min/kg predicted postoperative complications and death by univariate and stepwise regression analysis. Further, a GEC of more than 4 mg/min/kg was also associated with longer survival. CONCLUSIONS: This prospective study establishes the preoperative determination of the hepatic reserve by GEC as a strong independent and valuable predictor for short- and long-term outcome in patients with primary and secondary hepatic tumors undergoing resection.

Adolescent↗