Ronald Mårvik

Intra-abdominal vagal blocking (VBLOC therapy): Clinical results with a new implantable medical device

BACKGROUND A new medical device uses high-frequency electrical algorithms to create intermittent vagal blocking (VBLOC therapy). The aim is to assess the effects of vagal blocking on excess weight loss (EWL), safety, dietary intake, and vagal function. METHODS An open-label, 3-center study was conducted in obese subjects (body mass index [BMI] 35-50 kg/m(2)). Electrodes were implanted laparoscopically on both vagi near the esophagogastric junction to provide electrical block. Patients were followed for 6 months for body weight, safety, electrocardiogram, dietary intake, satiation, satiety, and plasma pancreatic polypeptide (PP) response to sham feeding. To specifically assess device effects alone, no diet or exercise programs were instituted. RESULTS Thirty-one patients (mean BMI, 41.2 +/- 1.4 kg/m(2)) received the device. Mean EWL at 4 and 12 weeks and 6 months after implant was 7.5%, 11.6%, and 14.2%, respectively (all P < .001); 25% of patients lost >25% EWL at 6 months (maximum, 36.8%). There were no deaths or device-related serious adverse events (AEs). Calorie intake decreased by >30% at 4 and 12 weeks and 6 months (all P <or= .01), with earlier satiation (P < .001) and reduced hunger (P = .005). After 12 weeks, plasma PP responses were suppressed (20 +/- 7 vs 42 +/- 19 pg/mL). Average percent EWL in patients with PP response <25 pg/mL was double that with PP response >25 pg/mL (P = .02). Three patients had serious AEs that required brief hospitalization, 1 each for lower respiratory tract, subcutaneous implant site seroma, and Clostridium difficile diarrhea. CONCLUSIONS Intermittent, intra-abdominal vagal blocking is associated with significant EWL and a desirable safety profile.

Open vs laparoscopic repair of perforated peptic ulcer

AbstractBackground: Most studies have found that the only advantage to the laparoscopic treatment of perforated peptic ulcer is a reduced need for postoperative analgesia. Therefore, we set out to assess the short-term outcome of open (OR) versus laparoscopic (LR) repair of perforated peptic ulcer. Methods: A total of 62 consecutive OR patients were compared with a concurrent cohort of 17 diagnosis-matched LR controls treated at the same hospital between 1991 and 1996. Results: The OR and LR patients were comparable for age, weight, American Society of Anesthesiologists (ASA) grade, Acute Physiology and Chronic Health Evaluation (APACHE II) score, Boey score, ulcer site, Mannheim Peritonitis Index (MPI), delay of surgery, Helicobacter pylori infection, nonsteroidal antiinflammatory drug (NSAID) intake, and previous abdominal surgery. More LR than OR patients were operated on by staff surgeons (χ2= 46.9, 1 d.f., p≪ 0.01). Mortality (OR: 12, LR: two), morbidity (OR: eight, LR: two), estimated blood loss (OR: 120 ml, LR: 95 ml), solid food intake resumption (OR: 5 days, LR 4 days), NSAID consumption (OR: 2,225 mg, LR: 1,815 mg), delayed gastric emptying (OR: two, OR: one), and hospital stay (OR: 9 days, LR: 7 days) were not significantly different for the two groups. Four LR patients (23.5%) were converted to OR due to failure to progress (n= 3) or posterior perforation (n= 1). Operating time was shorter in OR patients (65 min versus 92 min, p≪ 0.01). LR patients had reduced opioid consumption (256 mg versus 134 mg, p≪ 0.01). One LR and 16 OR patients were lost to follow-up. Median follow-up was 14 months (range, 2–55) and 18 months (range, 1–62) in OR and LR patients, respectively. There were more LR than OR patients with Visick score I (p= 0.002) and more OR than LR patients with Visick score II (p= 0.0001). Scores III and IV did not differ significantly. Conclusion: The laparoscopic repair of perforated peptic ulcer does not yield any additional benefits over the open repair.

3D ultrasound-based navigation for radiofrequency thermal ablation in the treatment of liver malignancies

BACKGROUND The aim of the study was to compare three methods for ultrasound-based guidance of a radiofrequency probe into liver tumors in a model setup. METHODS The liver model tumors were placed inside excised calf livers, and the radiofrequency probe was guided into the center using either a new 3D navigation method or two conventional 2D methods-freehand scanning and a method based on a biopsy guide. We performed 54 experiments, measuring the physical distance (all methods) and image distance (3D method only) from the tip of the probe to the center of the tumors. RESULTS Based on the physical measurements alone, the biopsy-based guiding performed better than both the 2D freehand and the 3D navigation method. However, the 3D image measurements showed that the tip of the probe was better positioned in the center of the model tumors for the 3D navigation method as compared to the physical measurement results for the 2D methods. CONCLUSION Although it was easier to position the radiofrequency probe accurately using the 3D image display technique, movement of the model tumor during 3D navigation is a challenge.

Effect of increased intraabdominal pressure on cardiac output and tissue blood flow assessed by color-labeled microspheres in the pig

BackgroundStudies of the hemodynamic effects associated with the pneumoperitoneum have had controversial results. We set out to investigate the effect of increased intraabdominal pressure (IAP) on cardiac output and tissue blood flow in various intraabdominal and extraabdominal organs using the color-labeled microsphere (CLM) technique.MethodsIAP was induced by CO2 insufflation in anesthetized pigs; 0,5, and 10 mmHg was used in the low-pressure group and 0, 15, and 24 mmHg in the high-pressure group. Tissue blood flow (ml.min−1.g−1) and cardiac output (CO) (ml/min) were determined by the CLM technique.ResultsCO decreased at IAP≥15 mmHg. Arterial PaCO2 and hydrogen ion concentration increased in response to all levels of IAP. Arterial PaO2, oxygen saturation, and bicarbonate ion concentration remained unchanged. Low IAP did not influence tissue blood flows in most of the organs. However, in the spleen, pancreas, esophagus, and gastric mucosal specimens, tissue blood flow was significantly decreased at 24 mmHg.ConclusionThe level of IAP used in current practice (10–12 12 mmHg) appears to be safe with regard to hemodynamic variables and tissues blood flow; however, higher levels may induce a decrease in cardiac output and tissue blood flow.

Relevance of TNBS-Colitis in Rats: A Methodological Study with Endoscopic, Histologic and Transcriptomic Characterization and Correlation to IBD

Background Rectal instillation of trinitrobenzene sulphonic acid (TNBS) in ethanol is an established model for inflammatory bowel disease (IBD). We aimed to 1) set up a TNBS-colitis protocol resulting in an endoscopic and histologic picture resembling IBD, 2) study the correlation between endoscopic, histologic and gene expression alterations at different time points after colitis induction, and 3) compare rat and human IBD mucosal transcriptomic data to evaluate whether TNBS-colitis is an appropriate model of IBD. Methodology/Principal Findings Five female Sprague Daley rats received TNBS diluted in 50% ethanol (18 mg/0.6 ml) rectally. The rats underwent colonoscopy with biopsy at different time points. RNA was extracted from rat biopsies and microarray was performed. PCR and in situ hybridization (ISH) were done for validation of microarray results. Rat microarray profiles were compared to human IBD expression profiles (25 ulcerative colitis Endoscopic score demonstrated mild to moderate colitis after three and seven days, but declined after twelve days. Histologic changes corresponded with the endoscopic appearance. Over-represented Gene Ontology Biological Processes included: Cell Adhesion, Immune Response, Lipid Metabolic Process, and Tissue Regeneration. IL-1α, IL-1β, TLR2, TLR4, PRNP were all significantly up-regulated, while PPARγ was significantly down-regulated. Among genes with highest fold change (FC) were SPINK4, LBP, ADA, RETNLB and IL-1α. The highest concordance in differential expression between TNBS and IBD transcriptomes was three days after colitis induction. ISH and PCR results corresponded with the microarray data. The most concordantly expressed biologically relevant pathways included TNF signaling, Cell junction organization, and Interleukin-1 processing. Conclusions/Significance Endoscopy with biopsies in TNBS-colitis is useful to follow temporal changes of inflammation visually and histologically, and to acquire tissue for gene expression analyses. TNBS-colitis is an appropriate model to study specific biological processes in IBD.

A comparative experimental study evaluating the performance of surgical robots aesop and endosista.

The aim of this study was to experimentally assess and compare the accuracy of the surgical robots Aesop and Endosista as camera holders for use in laparoscopic surgery. The performance of these two robotic systems was examined for linear (upwards, downwards, diagonal), complex, and “in and out” movements using laparoscopic training boxes. Standard distances and tests were used for each system, and the time required to achieve each task was measured. The majority of the linear movements of the verbal and preprogrammed modes of Aesop were quicker than those of Endosista. Diagonal movements were significantly faster with the preprogrammed-mode Aesop. Complex or three-dimensional movements were also significantly faster with both modes of Aesop than with Endosista. Under the experimental conditions, Aesop, particularly in the preprogrammed mode, is quicker and more accurate than Endosista.

Navigation in laparoscopy--prototype research platform for improved image-guided surgery.

The manipulation of the surgical field in laparoscopic surgery, through small incisions with rigid instruments, reduces free sight, dexterity, and tactile feedback. To help overcome some of these drawbacks, we present a prototype research and development platform, CustusX, for navigation in minimally invasive therapy. The system can also be used for planning and follow‐up studies. With this platform we can import and display a range of medical images, also real‐time data such as ultrasound and X‐ray, during surgery. Tracked surgical tools, such as pointers, video laparoscopes, graspers, and various probes, allow surgeons to interactively control the display of medical images during the procedure. This paper introduces navigation technologies and methods for laparoscopic therapy, and presents our software and hardware research platform. Furthermore, we illustrate the use of the system with examples from two pilots performed during laparoscopic therapy. We also present new developments that are currently being integrated into the system for future use in the operating room. Our initial results from pilot studies using this technology with preoperative images and guidance in the retroperitoneum during laparoscopy are promising. Finally, we shortly describe an ongoing multicenter study using this surgical navigation system platform.

Laparoscopic ultrasound: a survey of its current and future use, requirements, and integration with navigation technology

AbstractBackgroundLaparoscopic ultrasound (LUS) increases surgical safety by allowing the surgeon to see beyond the organ surface, by visualizing vascular structures and by improving surgical precision of tumor resection. A questionnaire-based survey was used to investigate the current use and future expectations of LUS technology.MethodsA questionnaire consisting of 26 questions was distributed manually at four different conferences (60% at the European Association for Endoscopic Surgery (EAES) conference, Stockholm 2008). The answers were summarized with descriptive statistics and nonparametric tests at a significance level of 0.05.ResultsThe questionnaire was answered by 177 surgeons from 40 different countries (85% from Europe). Of these surgeons, 43% use ultrasound during laparoscopic procedures. Generally, more LUS users are found at university hospitals than at general community hospitals. Surgeons use LUS primarily in procedures related to the liver (67% of the surgeons who use LUS), but LUS also is used in other procedures related to the pancreas, biliary tract, and colon. In a 5-year perspective, 82% of surgeons believe in an increased use of LUS, and 79% of surgeons also think that the use of LUS combined with navigation technology will increase and that the most important requirements for such a system are good image quality, easy interpretation, and a high degree of precision.ConclusionsAlthough the surgeons believe LUS has advantages, only 43% of the respondents reported using it. The surveyed surgeons were largely positive toward an increased use of LUS in a 5-year perspective and believe that LUS combined with navigation technology will contribute to improving the surgical precision of tumor resection.

Selective endoscopic retrograde cholangiography prior to laparoscopic cholecystectomy for gallstones

BACKGROUND To assess the outcome of endoscopic retrograde cholangiography (ERC) before laparoscopic cholecystectomy (LC) for symptomatic gallbladder and suspected duct stones. METHODS During 3 years, one or more of four criteria led to ERC: jaundice, choledocus >8 mm, cholestasis, and severe biliary pancreatitis. Endoscopic extraction (ESE) of ductal stones was attempted before LC. RESULTS In all, 990 patients were prospectively included. There were no exclusions. There were no deaths. A multivariate logistic regression analysis identified jaundice (P = 0.001), pancreatitis (P = 0.001), and cholestasis (P = 0.001) as statistically significant predictors of ductal stones. Choledocus >8 mm was not a significant predictor (P = 0.12). A total of 155 (16%) patients underwent ERC for suspected stones: 21 of 155 (13%) patients had no stones; and 6 of 134 (4%) patients had stone impaction cleared at open surgery. ERC clearance rate was 95% (128 of 134). LC was performed in 149 of 155 patients after a median interval of 3 days (range 1 to 7). Morbidity rates were 3% (4 of 134), 2% (3 of 149), and nil (0 of 6) after ESE, LC, or open surgery, respectively. Median hospital stay was 11 days. A total of 835 patients underwent LC with a 1.5% complication rate. Laparoscopic fluoro-cholangiography showed < or =3 mm-sized stones in 10 of 835 (1.2%) patients. No stones were reported at a median follow-up of 4 months including 990 patients. CONCLUSIONS Ninety-five percent of patients with ductal stones can be successfully and safely managed by ERC prior to LC.

Carbachol stimulation of gastric acid secretion and its effects on the parietal cell

The acid secretagogue effect of gastrin is mainly mediated by the release of enterochromaffin‐like (ECL) cell histamine, but the mechanism of muscarinic stimulation of acid secretion remains unclear. The results of studying aminopyrine uptake in isolated parietal cells, and histamine release in isolated ECL cells suggest that muscarinic agents may act both directly on the parietal cell and indirectly via histamine release from ECL cells. We examined parietal and ECL cell responses to the muscarinic agent carbamylcholine (carbachol) in conscious rats and in rat isolated vascularly perfused stomachs. Intravenous carbachol stimulated acid secretion in conscious gastric fistula rats and increased H+K+ ATPase mRNA abundance, indicating activation of parietal cells. In these experiments there was no increase in portal venous histamine, or in oxyntic mucosal histidine decarboxylase (HDC) enzyme activity and HDC mRNA abundance. In rat isolated stomachs stimulated with carbachol in the dose range 10 nM–1 mM only the 1 μM concentration increased venous histamine significantly. We concluded that the muscarinic agent carbachol stimulates acid secretion and H+K+ ATPase mRNA in vivo by a direct effect on the parietal cell, that does not depend on the release of ECL cell histamine.