The effect of hypergastrinemia following sleeve gastrectomy and pantoprazole on type 2 diabetes mellitus and beta-cell mass in Goto-Kakizaki rats.

PURPOSE: Metabolic surgery alters the secretion of gastrointestinal hormones that influence glycemic control. Elevated gastrin has been suggested to benefit patients with type 2 diabetes and has been reported following sleeve gastrectomy in rats. The present study compares the effect of hypergastrinemia following sleeve gastrectomy with proton-pump inhibitor therapy on glycemic control and beta-cell mass in lean, diabetic animals. METHODS: Thirty-three diabetic Goto-Kakizaki rats were randomized into pantoprazole + sham operation (GK-PPI), sleeve gastrectomy (GK-SG) and vehicle + sham operation (GK-V). Body weight, glucose parameters, HbA1c, glucagon-like peptide 1, gastrin, insulin and lipids were evaluated for eighteen postoperative weeks. Total beta-cell mass was quantified by optical projection tomography. RESULTS: After surgery, body weight development was equal among groups (P g = 0.75). Fasting and stimulated gastrin increased for GK-PPI and GK-SG vs. GK-V (p < 0.05 for all). Fasting blood glucose was decreased for GK-PPI and GK-SG vs. GK-V (p < 0.05 and p = 0.052). HbA1c was lower for GK-SG vs. GK-V at 6 weeks and for GK-PPI vs. GK-V at twelve- and eighteen weeks postoperative (p < 0.05 for all); a borderline difference was observed for GK-SG vs. GK-V at 18 weeks (p = 0.054). Total- and LDL cholesterol was elevated for GK-PPI compared to the other two groups (p < 0.05 for all). Beta-cell mass did not differ among groups (p = 0.35). CONCLUSIONS: Hypergastrinemia following sleeve gastrectomy and pantoprazole has a similar, modest effect on glycemic control in Goto-Kakizaki rats but does not enhance beta-cell mass after 18 weeks. Hypergastrinemia in the setting of T2DM might be of clinical relevance.

Navigated retrograde endoscopic myotomy (REM) for the treatment of therapy-resistant achalasia.

BACKGROUND: In achalasia, muscle spasm may involve the proximal esophagus. When the muscle spasm is located in the proximal esophagus, conventional per oral endoscopic myotomy (POEM) may not be sufficient to relieve symptoms. In this paper, we describe retrograde endoscopic myotomy (REM) as a novel approach to perform myotomy of the proximal esophagus, with the application of a navigation tool for anatomical guidance during REM. We aim to evaluate the feasibility and safety of REM and usefulness of the navigation during REM. METHOD: A 42-year-old male with type III achalasia who was treated with laparoscopic myotomy with fundoplication, multiple pneumatic balloon dilations, Botox injections and anterior POEM of the middle and distal esophagus without symptomatic effect. Repeated high-resolution- manometry (HRM) revealed occluding contractions of high amplitude around and above the aortic arch. A probe-based real-time electromagnetic navigation platform was used to facilitate real-time anatomical orientation and to evaluate myotomy position and length during REM. RESULTS: The navigation system aided in identifying the major structures of the mediastinum, and position and length of the myotomy. Twelve weeks after REM, the Eckardt score fell from seven at baseline seven to two. We also observed improvement with reduction of the pressure at the level of previous spasms in the proximal esophagus from 124 mmHg to 8 mmHg on HRM. CONCLUSION: REM makes the proximal esophagus accessible for endoscopic myotomy. Potential indication for REM is motility disorders in the proximal esophagus and therapy failure after POEM.

Gastric carcinoids after long-term use of a proton pump inhibitor.

BACKGROUND: Proton pump inhibitors (PPIs) are potent inhibitors of gastric acid secretion and give hypergastrinemia secondary to gastric hypoacidity. PPI treatment therefore induces enterochromaffin-like (ECL) cell hyperplasia. Long-term hypergastrinemia in rodents and man also leads to ECL cell neoplasia. Whether long-term PPI treatment will induce ECL cell neoplasia in man has been disputed. AIM: To describe gastric carcinoids in two patients with a history of long-term PPI use. RESULTS: Two patients had been taking PPI for 12-13 years due to gastro-oesophageal reflux disease. At routine upper gastrointestinal endoscopy a solitary tumour was found in the oxyntic mucosa of both patients. Histology from the tumours showed in both cases a well-differentiated neuroendocrine tumour. Biopsies from flat oxyntic mucosa showed no signs of atrophic gastritis and a normal presence of parietal cells in both cases, but hyperplasia of ECL cells. The tumour in patient 1 was resected endoscopically. After cessation of PPI treatment the tumour regressed in patient 2 and the ECL cell hyperplasia regressed in both patients. In patient 2 serum gastrin and chromogranin A were elevated during PPI treatment, and normalised after cessation of treatment. In patient 1, unfortunately, we had serum only after treatment, and at that time both parameters were normal. CONCLUSION: These cases show that hypergastrinemia secondary to proton pump inhibitors treatment, like other causes of hypergastrinemia, may induce enterochromaffin-like cell carcinoids in man.

Prevalence of all relevant eating disorders in patients waiting for bariatric surgery: a comparison between patients with and without eating disorders.

OBJECTIVE: To study the prevalence of all relevant eating disorders in 157 obese patients waiting for bariatric surgery. Another aim was to explore for possible differences between gender, and those with and without ED. The dependent variables were: socio-demographic characteristics, BMI, obesity onset, and obesity-related somatic diseases. METHODS: ED was assessed using the self-report questionnaire, "Eating Disorders in Obesity" (EDO). The patients answered a questionnaire that targeted socio-demographic and health information. RESULTS: Subgroups were based on the patients responses to items on the EDO: 1 patient (0.6%) with Bulimia Nervosa (BN), 6 (3.8%) with Eating Disorder Not Otherwise Specified (EDNOS), 21 (13.4%) with Binge Eating Disorder (BED), and 23 (14.6%) with Binge Eating (BE). The patients in the EDNOS group were those who lacked one criterion of the BN diagnosis. The patients in the BE group lacked one criterion of the BED diagnosis. Twenty-eight (17.8%) fulfilled the DSM-IV-TR criteria for ED. When patients with BE were added, 51 patients (32.5%) were identified with ED or sub-threshold ED. In the explorative part of the study, no gender differences in socio-demographic variables, BMI, obesity onset, and obesity-related somatic diseases emerged. With the exception of age, no differences were found in these variables between those with and without ED. CONCLUSION: Employing all relevant eating disorders and binge eating symptoms (BE) for this population identified patients with pathological eating behaviors, which are not detected in previous studies measuring only BED and BE.

Ergonomics of disposable handles for minimally invasive surgery.

BACKGROUND: The ergonomic deficiencies of currently available minimally invasive surgery (MIS) instrument handles have been addressed in many studies. In this study, a new ergonomic pistol handle concept, realized as a prototype, and two disposable ring handles were investigated according to ergonomic properties set by new European standards. METHODS: In this study, 25 volunteers performed four practical tasks to evaluate the ergonomics of the handles used in standard operating procedures (e.g., measuring a suture and cutting to length, precise maneuvering and targeting, and dissection of a gallbladder). Moreover, 20 participants underwent electromyography (EMG) tests to measure the muscle strain they experienced while carrying out the basic functions (grasp, rotate, and maneuver) in the x, y, and z axes. The data measured included the number of errors, the time required for task completion, perception of pressure areas, and EMG data. The values for usability in the test were effectiveness, efficiency, and user satisfaction. Surveys relating to the subjective rating were completed after each task for each of the three handles tested. RESULTS: Each handle except the new prototype caused pressure areas and pain. Extreme differences in muscle strain could not be observed for any of the three handles. Experienced surgeons worked more quickly with the prototype when measuring and cutting a suture (approximately 20%) and during precise maneuvering and targeting (approximately 20%). On the other hand, they completed the dissection task faster with the handle manufactured by Ethicon. Fewer errors were made with the prototype in dissection of the gallbladder. In contrast to the handles available on the market, the prototype was always rated as positive by the volunteers in the subjective surveys. CONCLUSIONS: None of the handles could fulfil all of the requirements with top scores. Each handle had its advantages and disadvantages. In contrast to the ring handles, the volunteers could fulfil most of the tasks more efficiently using the prototype handle without any remarkable pressure areas, cramps, or pain.

Navigated ultrasound in laparoscopic surgery.

Laparoscopic surgery is performed through small incisions that limit free sight and possibility to palpate organs. Although endoscopes provide an overview of organs inside the body, information beyond the surface of the organs is missing. Ultrasound can provide real-time essential information of inside organs, which is valuable for increased safety and accuracy in guidance of procedures. We have tested the use of 2D and 3D ultrasound combined with 3D CT data in a prototype navigation system. In our laboratory, micro-positioning sensors were integrated into a flexible intraoperative ultrasound probe, making it possible to measure the position and orientation of the real-time 2D ultrasound image as well as to perform freehand 3D ultrasound acquisitions. Furthermore, we also present a setup with the probe optically tracked from the shaft with the flexible part locked in one position. We evaluated the accuracy of the 3D laparoscopic ultrasound solution and obtained average values ranging from 1.6% to 3.6% volume deviation from the phantom specifications. Furthermore, we investigated the use of an electromagnetic tracking in the operating room. The results showed that the operating room setup disturbs the electromagnetic tracking signal by increasing the root mean square (RMS) distance error from 0.3 mm to 2.3 mm in the center of the measurement volume, but the surgical instruments and the ultrasound probe added no further inaccuracies. Tracked surgical tools, such as endoscopes, pointers, and probes, allowed surgeons to interactively control the display of both registered preoperative medical images, as well as intraoperatively acquired 3D ultrasound data, and have potential to increase the safety of guidance of surgical procedures.

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 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.

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.

Ergonomic design criteria for a novel laparoscopic tool handle with tactile feedback.

Laparoscopic surgery has many ergonomic disadvantages often not considered in the design of instruments. The poorly designed surgical tools produce inconveniences in both functional and cognitive aspects; including tactile sensation and visual-motor space coordination. The aim of this article is to find out how laparoscopic handle design can be improved by combining classical ergonomic guidelines with tactile feedback related to handle design. The article briefly discusses how the human hand and hand-held tools are used to perform tasks. An ergonomic handle for laparoscopic grasping, with a built-in tactile sensation display, is presented. Our review of laparoscopic instruments reveals important aspects for handle design. It is concluded that there is a need for greater awareness of ergonomic guidelines for users' sensory requirements when designing and manufacturing laparoscopic instruments.

Hemodynamic and tissue blood flow responses to long-term pneumoperitoneum and hypercapnia in the pig.

BACKGROUND: Increased peritoneal blood flow may influence the ability of cancer cells to adhere to and survive on the peritoneal surface during and after laparoscopic cancer surgery. Carbon dioxide (CO2) pneumoperitoneum is associated with a marked blood flow increase in the peritoneum. However, it is not clear whether the vasodilatory effect in the peritoneum is related to a local or systemic effect of CO2. METHODS: In this study, 21 pigs were exposed to pneumoperitoneum produced with either CO2 (n = 7) or helium (He) (n = 7) insufflation at 10 mmHg for 4 h, or to two consecutive levels of hypercapnia (7 and 11 kPa) (n = 7) produced by the addition of CO2 to the inhalational gas mixture. Tissue blood flow measurements were performed using the colored microsphere technique. RESULTS: Blood flow in peritoneal tissue increased during CO2, but not He, pneumoperitoneum, whereas it did not change at any level of hypercapnia alone. There was no change in blood flow in most organs at the partial pressure of CO2 (PaCO2) level of 7 kPa. However, at a PaCO2 of 11 kPa, blood flow was increased in the central nervous system, myocardium, and some gastrointestinal organs. The blood flow decreased markedly in all striated muscular tissues during both levels of hypercapnia. CONCLUSION: The effect of CO2 on peritoneal blood flow during laparoscopic surgery is a local effect, and not attributable to central hemodynamic effects of CO2 pneumoperitoneum or high systemic levels of CO2.

Development of a total colonoscopy rat model with endoscopic submucosal injection of the cecal wall.

BACKGROUND: Experimental models of colorectal tumor require either laparotomy for induction or anastomosis following resection. The long murine cecum avoids the need for an anastomosis, making the cecum the preferred site for induction. This study aimed to evaluate total colonoscopy with submucosal injection of cecal wall (TCWI) in rats in terms of failure rate (FR), complication rate (CR), and reproducibility (R). METHODS: A bolus of bowel prep was given. Anesthesia was injected intraperitoneally. A video fiberscope (5.9 mm outer diameter, 180/90 degrees up/down bending, 100/100 degrees right/left bending, 103 cm working length, 120 degrees view field, and 2.0 mm channel) allowed for irrigation and suction. Saline 1 ml was injected in the cecal wall through a 4-mm-long, 23-gauge needle placed on a 3-mm wire, resulting in a blister. FR was a failure to reach and inject the cecum. Rats were allowed to recover. CR was measured at necropsy. R was assessed by comparing TCWI time, FR, and CR for three investigators. Sample size of 120 (type I error, 0.05; power, 80%) was based on a pilot study. Data are presented as median (range). RESULTS: A total of two of 122 rats (1.6%) died after prep or anesthesia. Bowel prep resulted in 99.1% evacuation of solid feces. A total of 120 male Sprague-Dawley retired breeders weighing 592 g (range, 349-780) underwent TCWI. Scope depth was 28 cm (range, 20-36). Irrigating fluid was 290 ml (range, 100-600). TCWI time was 7 min (range, 4-28). FR was 4%. In three failed cases, the scope reached the ascending colon. CR was 2%. There were two perforations in the ascending colon. All three operators had similar TCWI time (p = 0.673), FR (p > 0.1), and CR (p > 0.1). A total of 98.3% of rats survived to planned sacrifice. At 48-h necropsy, the injection site was macroscopically identified in 118 rats. CONCLUSIONS: A safe and reproducible TCWI rat model has been achieved, which may provide a valuable tool in the future for studies of solid colorectal tumors.

Image-guided laparoscopic surgery. Review and current status.

The main drawback with laparoscopic surgery is that the surgeon is unable to palpate vessels, tumours and organs during surgery. Further-more, the laparoscope only provides a surface view of organs. There is a need for more advanced visualizations techniques that can enhance the display presented to the surgeon so that important information below the surface of the organs is included when planning the procedure as well as for guidance and control during treatment. In this paper, we present a review of the literature and the state of art within image-guided laparoscopic surgery. We describe our own experience using a prototype navigation system for advanced visualizations and guidance during laparoscopic procedures in the retroperitoneum. Furthermore, we show sample images from the Future Operating Room for laparoscopic surgery in Trondheim, where this technology is being further developed and tested in clinical studies. Our system is based on three-dimensional navigation technology, i.e. preoperatively acquired magnetic resonance or computed tomography data used in combination with tracked instruments, allowing the surgeon to interactively control the display of images prior to and during surgery with normal use of the instruments. In summary, we believe that abdominal image navigation using tracked instruments and advanced visualizations has a large potential for improving future laparoscopic surgery, especially in cases where vessels and anatomical relations beyond surfaces is difficult to identify using only a laparoscope. The technology helps the surgeon to better understand the anatomy and locate blood vessels. Accordingly, we believe that this new technology could increase safety and make it easier for the surgeon to perform successful laparoscopic surgery.

Postoperative morbidity and recurrence after local excision of rectal adenomas and rectal cancer by transanal endoscopic microsurgery.

OBJECTIVE: Tumours in the middle and upper part of the rectum are not easy accessible to local excision. Transanal endoscopic microsurgery (TEM) has been recommended for excision of sessile adenomas in the middle and upper part of the rectum, and for small cancers in patients not fit for major surgery. The purpose of this study was to evaluate postoperative morbidity and local recurrence after TEM. MATERIAL AND METHODS: Seventy-nine patients were treated by TEM in the period 1994-2001. The median age was 74 years. The indications for TEM were rectal adenoma in 72 patients and rectal cancer in 7 patients. The tumours were located within 18 cm from the dentate line, median 10 cm. There were performed 69 transmural and 10 mucosal excisions. Mean follow up was 24 months (range 1-95 months). Twenty (25%) patients died during the follow up period, two because of metastases and 18 of other causes. RESULTS: Seven patients had complications. Two (2.5%) patients had peroperative perforation in the intra-abdominal part of the rectum treated by laparotomy. Five (6%) patients had postoperative cardiopulmonal or surgical complications. Eight patients with benign pre-operative histopathological examination had cancer. The local recurrence rate (13%) was similar for adenomas and for carcinomas. CONCLUSION: TEM is a safe technique well tolerated also by high-risk patients, and should be the preferred method in patients with benign tumours in the middle and upper part of the rectum, and in selected cases of early rectal cancer. Benign pre-operative histology does not preclude malignancy and some patients may need further treatment for unexpected malignancy.

Laparoscopic navigation pointer for three-dimensional image-guided surgery.

BACKGROUND: The main drawback with the laparoscopic approach is that the surgeon is unable to palpate vessels, tumors, and organs during surgery. Furthermore, the laparoscope provides only surface view of organs. There is a need for more advanced visualizations that can enhance the view to include information below the surface of the organs for planning of the procedure and for control and guidance during treatment. METHODS: We propose three-dimensional (3D) navigation technology based on preoperatively acquired magnetic resonance or computed tomography data used in combination with a laparoscopic navigation pointer (LNP). The LNP has an attached position tracker that allows the surgeon to control the display of images interactively before and during surgery. This study evaluated the patient registration accuracy, the feasibility of image-based navigation and, qualitatively, the navigation precision in the retroperitoneum during laparoscopic surgery. RESULTS: This technology was used during the treatment of six patients (involving adrenalectomies and a neuroma protruding into the pelvis). An average patient registration accuracy of 6.90 mm was achieved. The precision during navigation in the retroperitoneum was, in some cases, better than the patient registration accuracy suggested. The technology helped the surgeons to understand better the anatomy and to locate blood vessels. CONCLUSIONS: In the reported cases, the LNP was a useful tool for image guidance in laparoscopic surgery, both for planning the surgical approach in detail and for guidance. The authors believe that adominal 3D image guidance using an LNP has a large potential for improving laparoscopic surgery, especially when vessels and anatomic relations may be difficult to identify using only a laparoscope. Accordingly, they believe this new technology could increase safety and make it easier for the surgeon to perform successful laparoscopic surgery.

Preserving the superior rectal artery in laparoscopic sigmoid resection for complete rectal prolapse.

Sigmoid resection is indicated in the treatment of complete rectal prolapse (CRP) in patients with prolonged colorectal transit time (CTT). Its use however has been limited due to fear of anastomotic leakage. This study challenges the current practice of dividing the mesorectum by prospectively evaluating the impact of sparing the superior rectal artery (SRA) on leak rates after laparoscopic sigmoid resection (LSR) for CRP. During 30 months data on 33 selected patients with CRP were prospectively collected. Three patients were withdrawn from the analysis, as they had neither resection nor anastomosis. Twenty-nine women and one man (median age 55 range 21-83 years) underwent LSR with preservation of SRA for a median CRP of 8 (3-15) cm. There were 20 ASA I and 10 ASA II patients. Ten patients had undergone previous surgery. Four patients complained of dyschezia, whereas incontinence was present in 26 patients. Anal ultrasound showed isolated internal sphincter defects in two patients. Four young adults (21-32 years) had normal CTT, whereas 26 older patients had a median CTT of 5 (4-6) days. Defecography demonstrated 10 enteroceles, two sigmoidoceles, and one rectal hernia through the levator ani muscle. Mortality was nil. Median operating room time was 180 (120-330) min, suprapubic incision length 5 (3-7) cm, estimated blood loss 150 (50-500) ml, specimen length 20 (12-45) cm, solid food resumption 3 (1-6) days, and length of stay 4.5 (2-7) days. Thirty-day complications were not related to anastomosing and occurred in 20% of the patients. Although the evidence provided by the present study suggests that sparing SRA has a favorable impact on anastomotic leak rates, these nonrandomized results need further evaluation. The division of the mesorectum at the rectosigmoid junction seems not necessary, and its sparing should therefore be considered as it may contain anastomotic leak rates.

Medical image quality as a socio-technical phenomenon.

OBJECTIVES: The study aims to interpret image quality in laparoscopic surgery not only as a technical parameter but also as the result of the situation of use. METHODS: Observational studies of laparoscopy in use, semi-structured and informal interviews with laparoscopists. RESULTS: When medical images are digitized to exploit novel technical possibilities, image quality becomes a paramount issue. Image quality is often discussed exclusively in technical terms, but the socio-technical study of image quality in surgical telemedicine presented in this paper showed that it is definitely more than a purely technical parameter. CONCLUSIONS: While the resulting quality of the image was significantly shaped by the persons involved, the concept of "quality" itself was also relative and changing with the situation of use. A given technology does not determine image quality. Rather than focusing only on the technical quality, the attention of designers and decision makers should also be directed to the socio-technical network surrounding the image and its use.

Effect of carbon dioxide pneumoperitoneum on tissue blood flow in the peritoneum, rectus abdominis, and diaphragm muscles.

BACKGROUND: Changes in local blood flow may play a role in the pathogenesis of port-site metastasis. This study aimed to investigate the effect of pneumoperitoneum induced by carbon dioxide (CO2) on the blood flow in the peritoneum and abdominal wall muscle layers, which are target structures for this phenomenon. METHODS: The study was performed on domestic farm swine of both genders weighing 20 to 25 kg. Intraabdominal pressures (IAP) of 0, 5, and 10 mmHg were produced by either CO2 ( n = 9) or helium (He) ( n = 6) insufflations. The colored microsphere technique was used to measure blood flow distributions in the parietal peritoneum, rectus abdominis, and diaphragm muscles. RESULTS: Insufflation of CO2 was associated with a threefold increase in blood flow of the parietal peritoneum at both 5 and 10 mmHg IAP ( p < 0.001 for both pressure levels). In contrast, insufflation of He caused a significant decrease in blood flow in the parietal peritoneum at both 5 and 10 mmHg ( p < 0.05). In the rectus abdominis and diaphragm muscles, blood flow remained unchanged after insufflation of CO2 at both 5 and 10 mmHg IAP. However, after insufflation of He, there was a substantial decrease in blood flow both in the rectus abdominis and diaphragm muscles at both 5 mmHg ( p < 0.01 and p < 0.05, respectively) and 10 mmHg ( p < 0.001 and p < 0.01, respectively). CONCLUSIONS: Despite high intraabdominal pressure, tissues surrounding the abdominal cavity, particularly the peritoneum, respond to insufflation of CO2 with increased blood flow, which may favor the growth of tumor cells.

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.

Laparoscopic antiperistaltic versus isoperistaltic gastrojejunostomy for palliation of gastric outlet obstruction in advanced cancer.

The purpose of the study was to compare the impact of the peristaltic orientation of laparoscopic gastrojejunal anastomoses (LGJ) in patients with malignant gastric outlet obstruction (GOO) on postoperative delayed-return gastric emptying (DRGE) rates. GOO was defined as complete holdup of contrast at barium meal and/or failure of gastroscope to pass beyond stricture. DRGE was defined as inability to eat regular diet by day 10. Thirty-four patients undergoing antiperistaltic LGJ were compared with 21 patients undergoing isoperistaltic LGJ at two institutions during the same period. Thirty-day mortality was 5.4%, and median survival was 6.2 months. Thirty-day morbidity was 20%, and conversion rate was 3.6%. DRGE rates were increased after isoperistaltic LGJ (0 vs. 3; P < 0.05), but patient groups were not well matched for type of primary cancer (P < 0.05). All patients with DRGE resumed food intake 12 to 16 days after surgery. There were 21 admissions before death, with a reoperation rate of 11.5% and a recurrent GOO rate of 3.8%. Although no conclusions could be drawn about whether the peristaltic orientation of the anastomosis had a bearing on DRGE rates, LGJ resulted in an overall 6% rate of DRGE.