Ozanan R. Meireles

Reliable gastric closure after natural orifice translumenal endoscopic surgery (NOTES) using a novel automated flexible stapling device

BackgroundReliable closure of the translumenal incision is one of the main challenges facing natural orifice translumenal endoscopic surgery (NOTES). This study aimed to evaluate the use of an automated flexible stapling device (SurgASSIST) for closure of the gastrotomy incision in a porcine model.MethodsA double-channel gastroscope was advanced into the stomach. A gastric wall incision was made, and the endoscope was advanced into the peritoneal cavity. After peritoneoscopy, the endoscope was withdrawn into the stomach. The SurgASSIST stapler was advanced orally into the stomach. The gastrotomy edges were positioned between the opened stapler arms using two endoscopic grasping forceps. Stapler loads with and without a cutting blade were used for gastric closure. After firing of the stapler to close the gastric wall incision, x-ray with contrast was performed to assess for gastric leakage. At the end of the procedure, the animals were killed for a study of closure adequacy.ResultsFour acute animal experiments were performed. The delivery and positioning of the stapler were achieved, with technical difficulties mostly due to a short working length (60 cm) of the device. Firing of the staple delivered four rows of staples. Postmortem examination of pig 1 (when a cutting blade was used) demonstrated full-thickness closure of the gastric wall incision, but the cutting blade caused a transmural hole right at the end of the staple line. For this reason, we stopped using stapler loads with a cutting blade. In the three remaining animals (pigs 2–4), we were able to achieve a full-thickness closure of the gastric wall incision without any complications.ConclusionsThe flexible stapling device may provide a simple and reliable technique for lumenal closure after NOTES procedures. Further survival studies are currently under way to evaluate the long-term efficacy of gastric closure with the stapler after intraperitoneal interventions.

Hybrid minimally invasive surgery—a bridge between laparoscopic and translumenal surgery

BackgroundThe peroral transluminal approach to the peritoneal cavity appears safe, feasible, and may further reduce the invasiveness of surgery. However, flexible endoscopes have multiple limitations inside the peritoneal cavity, which can potentially be overcome by blending the use of both a laparoscope and a flexible upper endoscope—a hybrid approach. The goal of the present study was to evaluate a hybrid minimally invasive technique for cholecystectomy in a porcine model.MethodsHybrid cholecystectomies were performed in acute experiments on 50-kg pigs under general anesthesia. Pneumoperitoneum was created with a Veress needle, and a laparoscopic 10-mm port was inserted. Under laparoscopic observation, the gastric wall incision was done with an endoscopic needle-knife and sphincterotome, and the upper endoscope was advanced into the peritoneal cavity. A laparoscopic 10-mm port was inserted into the right upper quadrant of the abdomen for gallbladder traction to facilitate exposure of the cystic duct and artery. Via the biopsy channel of the flexible endoscope, and using a knife with an isolated tip, a needle knife, and clips, both the cystic duct and artery were identified, clipped, and transected. The gallbladder itself was then dissected and retracted through the mouth, and the gastric wall incision was closed with endoscopic clips.ResultsFive hybrid cholecystectomies were performed without complications. The laparoscopic port enabled a stable pneumoperitoneum, good traction and counter-traction, and improved spatial orientation and visualization. Necropsy did not reveal any intraperitoneal complications.ConclusionsThe hybrid approach increases safety of initial gastric puncture and gastric wall incision, improves orientation and navigation of the flexible endoscope inside the peritoneal cavity, simplifies peroral transgastric cholecystectomy, and could be used to decrease invasiveness of laparoscopic surgery and to facilitate development and clinical introduction of transgastric endoscopic procedures.

Comparison of intraabdominal pressures using the gastroscope and laparoscope for transgastric surgery

BackgroundThe peroral transgastric endoscopic approach for intraabdominal procedures appears to be feasible, although multiple aspects of this approach remain unclear. This study aimed to measure intraperitoneal pressure in a porcine model during the peroral transgastric endoscopic approach, comparing an endoscopic on-demand insufflator/light source with a standard autoregulated laparoscopic insufflator.MethodsAll experiments were performed with 50-kg female pigs under general anesthesia. A standard upper endoscope was advanced perorally through a gastric wall incision into the peritoneal cavity. The peritoneal cavity was insufflated with operating room air from an endoscopic light source/insufflator. Intraperitoneal pressure was measured by three routes: (1) through the endoscope biopsy channel, (2) through a 5-mm transabdominal laparoscopic port, and (3) through a 16-gauge Veress needle inserted into the peritoneal cavity through the anterior abdominal wall. The source of insufflation alternated between on-demand manual insufflation through the endoscopic light source/insufflator using room air and a standard autoregulated laparoscopic insufflator using carbon dioxide (CO2).ResultsSix acute experiments were performed. Intraperitoneal pressure measurements showed good correlation regardless of measurement route and were independent of the type of insufflation gas, whether room air or CO2. On-demand insufflation with the endoscopic light source/insufflator resulted in a wide variation in pressures (range, 4–32 mmHg; mean, 16.0 ± 11.7). Intraabdominal pressures using a standard autoregulated laparoscopic insufflator demonstrated minimal fluctuation (range, 8–15 mmHg; mean, 11.0 ± 2.2 mmHg) around a predetermined value.ConclusionUse of an on-demand unregulated endoscopic light source/insufflator for translumenal surgery can cause large variation in intraperitoneal pressures and intraabdominal hypertension, leading to the risk of hemodynamic and respiratory compromise. Safety may favor well-controlled intraabdominal pressures achieved with a standard autoregulated laparoscopic insufflator.

Linitis plastica presenting two years after elective Roux-en-Y gastric bypass for treatment of morbid obesity: a case report and review of the literature

reles.O According to the National Center for Health Services, 478 million Americans 420 years of age are obese [1]. Attempts at nonsurgical weight loss are often unsuccessful, resulting in modest weight loss that is unsustainable [2–4]. The laparoscopic Roux-en-Y gastric bypass (RYGB) produces up to 70% excess weight loss and accounts for 46% of the metabolic procedures completed annually [5,6]. Worldwide, gastric cancer is the fourth most common cancer and second leading cause of death. Linitis plastica (LP) is a diffusely infiltrative subset of gastric cancer associated with aggressive behavior and metastatic disease [7]. Herein is a case report of a patient in whom LP developed 2 years after laparoscopic RYGB was performed for the treatment of obesity.

Roux-en-Y gastric bypass is associated with an increased exposure to ionizing radiation

BACKGROUND Bariatric surgery provides for a reliable and sustainable solution to the obesity epidemic. The gold standard bariatric surgical procedure is the Roux-en-Y gastric bypass (RYGB). Assessment of this population preoperatively and work-up of postoperative complications often includes radiographic evaluation. Repeated exposure to radiation is not without complication. OBJECTIVE Assess the association between the RYGB and exposure to ionizing radiation. SETTING Academic medical center. METHODS Patients were identified by their ICD-9 code as having had a RYGB at the Massachusetts General Hospital (MGH) from 2002 to 2012. The number of abdominal and pelvis (A/P) computed tomography (CT) scans performed was determined and converted into an effective dose (ED) and expressed as milliSeiverts (mSv) to illustrate the biologic effects of radiation. RESULTS From 2002 to 2012, 1789 primary laparoscopic RYGBs were completed. Fifty-five revisional operations were completed on 51 patients. Of these, 38 had both their index and second operation at the MGH. A total of 1065 A/P CTs were completed in the laparoscopic RYGB population (mean = .6), and 106 A/P CTs were done in the revisional surgery cohort (mean = 2.8). The mean ED of radiation was 56.1 mSv and 19.5 mSv for the index and revisional populations, respectively. CONCLUSIONS This study demonstrated the significant cumulative radiation exposure attributable to A/P CTs. This exposes the patient to a potential increased risk of malignancy as well as imposing a financial burden on the healthcare system. The findings of this study raise the awareness of an increased risk of radiation exposure for this population and the necessity of creation of a dedicated algorithm for the mindful utilization of CT imaging.

Posterior reversible encephalopathy syndrome (PRES) after bariatric surgery--a potential consequence associated with rapid withdrawal of antihypertensive medications.

A 61-year-old woman with a medical history of intracerebral haemorrhage, hypertension, hyperlipidaemia and carotid stenosis presented to the emergency department with altered mental status 3 weeks after undergoing a vertical sleeve gastrectomy for severe obesity. She presented with a hypertensive emergency and a National Institutes of Health Stroke Scale of 4. CT of the head was unrevealing. MRI showed an abnormal signal within the bilateral posterior border-zone areas, with several foci in the parietal and occipital lobes, and thalami, suggestive of posterior reversible encephalopathy syndrome (PRES). The patient was initially placed on a labetalol drip and her preoperative antihypertensive medications—amlodipine, captopril, triamterene and hydrochlorothiazide—were gradually reintroduced. She returned to her baseline and was stable on discharge. Rapid withdrawal of antihypertensive medications in the early postoperative period of bariatric surgery was the aetiology of PRES in this patient. This case report discusses postoperative care of bariatric surgery patients having hypertension.

Machine learning and coresets for automated real-time video segmentation of laparoscopic and robot-assisted surgery

Context-aware segmentation of laparoscopic and robot assisted surgical video has been shown to improve performance and perioperative workflow efficiency, and can be used for education and time-critical consultation. Modern pressures on productivity preclude manual video analysis, and hospital policies and legacy infrastructure are often prohibitive of recording and storing large amounts of data. In this paper we present a system that automatically generates a video segmentation of laparoscopic and robot-assisted procedures according to their underlying surgical phases using minimal computational resources, and low amounts of training data. Our system uses an SVM and HMM in combination with an augmented feature space that captures the variability of these video streams without requiring analysis of the nonrigid and variable environment. By using the data reduction capabilities of online k-segment coreset algorithms we can efficiently produce results of approximately equal quality, in realtime. We evaluate our system in cross-validation experiments and propose a blueprint for piloting such a system in a real operating room environment with minimal risk factors.

POEM for Chagas Disease-Induced Achalasia

Chagas disease is a relatively uncommon but fascinating cause of esophageal dysmotility. While the GI manifestations of Chagas have been studied for many years, there is relatively little data available to guide the use of Peroral Endoscopic Myotomy (POEM) in this disease. In this chapter, the pathophysiology and treatment of Chagas are reviewed. Technical considerations regarding the surgical management of Chagas-related esophageal disease, including the potential role of POEM, are described.

Peroral Endoscopic Myotomy (POEM) for Achalasia

Achalasia, a primary motility disorder of the esophagus, is the result of improper relaxation of the lower esophageal sphincter and has an incidence rangin

Transesophageal Endoscopic Myotomy (TEEM) for the Treatment of Achalasia – The United States Human Experience

The stem cell spheroids were infected with NV1066, a third-generation herpesvirus, or NDV-F3aa-GFP, a Newcastle Disease virus mutant. Both viruses carried the marker gene green fluorescent protein (GFP), which allowed monitoring by fluorescent microscopy. Cell cycle analysis and cell migration assay were also performed. Results: Viral infection of cancer stem cells was rapid (GFP expression was seen by 24 hours). The viruses from both families each produced efficient infection and killing of cancer. At doses of multiplicity of infection (MOI, number of viruses per tumor cell) of 0.5 or 1, >95% of cells were dead by day 6. Infection with virus also produced decreased migratory capacity of the cancer stem cells and shifted the population to a higher fraction in S phase. Conclusion: Multiple types of oncolytic viruses effectively target the stem cell subpopulation of pancreatic cancer cells. Infection decreases metastatic potential and effects killing of such stem cells. These data support clinical studies of oncolytic viruses in the treatment of chemoand radioresistant tumors.