Michael R. Marohn

Does pancreatic duct stenting decrease the rate of pancreatic fistula following pancreaticoduodenectomy? Results of a prospective randomized trial.

Pancreatic duct stenting remains an attractive strategy to reduce the incidence of pancreatic fistulas following pancreaticoduodenectomy (PD) with encouraging results in both retrospective and prospective studies. We performed a prospective randomized trial to test the hypothesis that internal pancreatic duct stenting reduces the development of pancreatic fistulas following PD. Two hundred thirty-eight patients were randomized to either receive a pancreatic stent (S) or no stent (NS), and stratified according to the texture of the pancreatic remnant (soft/normal versus hard). Four patients were excluded from the study; in three instances due to a pancreatic duct that was too small to cannulate and in the other instance because a total pancreatectomy was performed. Patients who randomized to the S group had a 6-cm-long segment of a plastic pediatric feeding tube used to stent the pancreaticojejunostomy anastomosis. In patients with a soft pancreas, 57 randomized to the S group and 56 randomized to the NS group. In patients with a hard pancreas, 58 randomized to the S group and 63 randomized to the NS group. The S and NS groups for the entire study population, as well as for the subgroup of high-risk patients with soft pancreata, were similar as regard to demographics, past medical history, preoperative symptoms, preoperative procedures, and intraoperative data. The pancreatic fistula rate for the entire study population was 9.4%. The fistula rates in the S and NS subgroups with hard pancreata were similar, at 1.7% and 4.8% (P=0.4), respectively. The fistula rates in the S and NS subgroups with soft pancreata were also similar, at 21.1% and 10.7% (P=0.1), respectively. A nonstatistically significant increase in the pancreatic fistula rate in the S group persisted after adjusting for the operating surgeon and technical details of the operation (e.g., anastomotic technique, anastomotic orientation, pancreatic duct size, and number of intra-abdominal drains placed). In patients with soft pancreata, 63% percent of the pancreatic fistulas in stented patients required adjustment to the clinical pathway (including two deaths), compared to 47% of the pancreatic fistulas in patients in the NS group (P=0.3). Internal pancreatic duct stenting does not decrease the frequency or the severity of postoperative pancreatic fistulas.

A consensus document on robotic surgery

“Robotic surgery” originated as an imprecise term, but it has been widely used by both the medical and lay press and is now generally accepted by the medical community. The term refers to surgical technology that places a computer-assisted electromechanical device in the path between the surgeon and the patient. A more scientifically accurate term for current devices would be “remote telepresence manipulators” because available technology does not generally function without the explicit and direct control of a human operator. For the purposes of the document, we define robotic surgery as a surgical procedure or technology that adds a computer technology–enhanced device to the interaction between a surgeon and a patient during a surgical operation and assumes some degree of control heretofore completely reserved for the surgeon. For example, in laparoscopic surgery, the surgeon directly controls and manipulates tissue, albeit at some distance from the patient and through a fulcrum point in the abdominal wall. This differs from the use of current robotic devices, whereby the surgeon sits at a console, typically in the operating room but outside the sterile field, directing and controlling the movements of one or more robotic arms. Although the surgeon still maintains control over the operation, the control is indirect and effected from an increased distance. This definition of robotic surgery encompasses micromanipulators, remotely controlled endoscopes, and console-manipulator devices. The key elements are enhancements of the surgeon’s abilities—be they vision, tissue manipulation, or tissue sensing—and alteration of the traditional direct local contact between surgeon and patient.

Peripheral blood MicroRNAs distinguish active ulcerative colitis and Crohn's disease

Background: Crohns disease (CD) and ulcerative colitis (UC) result from pathophysiologically distinct dysregulated immune responses, as evidenced by the preponderance of differing immune cell mediators and circulating cytokine expression profiles. MicroRNAs (miRNAs) are small, noncoding RNAs that act as negative regulators of gene expression and have an increasingly recognized role in immune regulation. We hypothesized that differences in circulating immune cells in CD and UC patients are reflected by altered miRNA expression and that miRNA expression patterns can distinguish CD and UC from normal healthy individuals. Methods: Peripheral blood was obtained from patients with active CD, inactive CD, active UC, inactive UC, and normal healthy adults. Total RNA was isolated and miRNA expression assessed using miRNA microarray and validated by mature miRNA quantitative reverse‐transcription polymerase chain reaction. Results: Five miRNAs were significantly increased and two miRNAs (149* and miRplus‐F1065) were significantly decreased in the blood of active CD patients as compared to healthy controls. Twelve miRNAs were significantly increased and miRNA‐505* was significantly decreased in the blood of active UC patients as compared to healthy controls. Ten miRNAs were significantly increased and one miRNA was significantly decreased in the blood of active UC patients as compared to active CD patients. Conclusions: Peripheral blood miRNAs can be used to distinguish active CD and UC from healthy controls. The data support the evidence that CD and UC are associated with different circulating immune cells types and that the differential expression of peripheral blood miRNAs may form the basis of future diagnostic tests for inflammatory bowel disease. (Inflamm Bowel Dis 2011;)

A Diagnostic Predictor Model for Indeterminate or Suspicious Thyroid FNA Samples

BACKGROUND The management of patients with thyroid fine-needle aspiration (FNA) specimens that are neither benign nor malignant still remains problematic. Efforts to improve their management have focused on identifying risk factors that predict malignancy. This study seeks to identify clinical and tumor characteristics that predict thyroid malignancy among patients with indeterminate or suspicious FNA and to develop a diagnostic predictor model. METHODS The records of 639 patients with an indeterminate or suspicious thyroid FNA between January 1995 and April 2005 were reviewed. Patient and tumor characteristics were evaluated for their potential to predict malignancy in the final surgical histopathology. A diagnostic predictor model was designed based on statistically significant predictors. Patients seen between April 2005 and April 2007 were used to validate the model. RESULTS Patient age, nodule size, and FNA cytopathology were identified as risk factors. Patients at extremes of age were at increased risk. Patients 50 years of age had the lowest risk of malignancy. For patients less than age 50, the risk increased 3% for each year decrease in age (p = 0.001). After 50, the risk increased 3.4% for each year increase in age (p = 0.016). Nodules 2.5 cm had the lowest likelihood of malignancy. For smaller nodules, the risk increased 53% per cm decrease in size (p < 0.001). For larger nodules, the risk increased 39% per cm increase (p < 0.001). Patients with FNA cytology suspicious for papillary thyroid carcinoma had the greatest risk of malignancy (p < 0.001). CONCLUSIONS A predictor model was created using the variables age, nodule size, and FNA cytology to predict thyroid malignancy.

Identification of genes differentially expressed in benign versus malignant thyroid tumors

Purpose: Although fine-needle aspiration biopsy is the most useful diagnostic tool in evaluating a thyroid nodule, preoperative diagnosis of thyroid nodules is frequently imprecise, with up to 30% of fine-needle aspiration biopsy cytology samples reported as “suspicious” or “indeterminate.” Therefore, other adjuncts, such as molecular-based diagnostic approaches are needed in the preoperative distinction of these lesions. Experimental Design: In an attempt to identify diagnostic markers for the preoperative distinction of these lesions, we chose to study by microarray analysis the eight different thyroid tumor subtypes that can present a diagnostic challenge to the clinician. Results: Our microarray-based analysis of 94 thyroid tumors identified 75 genes that are differentially expressed between benign and malignant tumor subtypes. Of these, 33 were overexpressed and 42 were underexpressed in malignant compared with benign thyroid tumors. Statistical analysis of these genes, using nearest-neighbor classification, showed a 73% sensitivity and 82% specificity in predicting malignancy. Real-time reverse transcription–PCR validation for 12 of these genes was confirmatory. Western blot and immunohistochemical analyses of one of the genes, high mobility group AT-hook 2, further validated the microarray and real-time reverse transcription–PCR data. Conclusions: Our results suggest that these 12 genes could be useful in the development of a panel of markers to differentiate benign from malignant tumors and thus serve as an important first step in solving the clinical problem associated with suspicious thyroid lesions.

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.

Transcontinental telesurgical nephrectomy using the da Vinci robot in a porcine model.

OBJECTIVES Robotic telesurgery has been demonstrated over long distances and offers theoretical benefits to urologic training and the care of patients in remote regions. The multiple arms and three-dimensional vision of the da Vinci robotic system provide a platform conducive to long-distance telementoring and telesurgery. Whereas prior telesurgical efforts have used dedicated lines for information transmission, the public Internet offers a less expensive alternative. It was the intent of this study to test the validity of using the da Vinci system in urologic telesurgery, and to conduct telerobotic nephrectomies using the public Internet. METHODS We performed four right nephrectomies in porcine models using the da Vinci robotic system. Telementoring and telesurgical approaches were used, with resident surgeons operating a console adjacent to the swine, while attending surgeons simultaneously operated a second console at distances of 1300 and 2400 miles from the operating room. RESULTS All four procedures and both telementoring and telesurgical models were successful. Round-trip delays from 450 to 900 ms were demonstrated. Blood loss was minimal, and there were no intraoperative complications. CONCLUSIONS This study represents the first use of the da Vinci Surgical System in urologic telesurgery and the first successful telesurgical nephrectomy in an animal model.

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.

Serum anti-glycan antibody biomarkers for inflammatory bowel disease diagnosis and progression: a systematic review and meta-analysis.

Background: Anti‐glycan antibody serologic markers may serve as a useful adjunct in the diagnosis/prognosis of inflammatory bowel disease (IBD), including Crohns disease (CD) and ulcerative colitis (UC). This meta‐analysis/systemic review aimed to evaluate the diagnostic value, as well as the association of anti‐glycan biomarkers with IBD susceptible gene variants, disease complications, and the need for surgery in IBD. Methods: The diagnostic odds ratio (DOR), 95% confidence interval (CI), and sensitivity/specificity were used to compare the diagnostic value of individual and combinations of anti‐glycan markers and their association with disease course (complication and/or need for surgery). Results: Fourteen studies were included in the systemic review and nine in the meta‐analysis. Individually, anti‐Saccharomyces cervisiae antibodies (ASCA) had the highest DOR for differentiating IBD from healthy (DOR 21.1; 1.8–247.3; two studies), and CD from UC (DOR 10.2; CI 7.7–13.7; seven studies). For combination of ≥2 markers, the DOR was 2.8 (CI 2.2–3.6; two studies) for CD‐related surgery, higher than any individual marker, while the DOR for differentiating CD from UC was 10.2 (CI 5.6–18.5; three studies) and for complication was 2.8 (CI 2.2–3.7; two studies), similar to individual markers. Conclusions: ASCA had the highest diagnostic value among individual anti‐glycan markers. While anti‐chitobioside carbohydrate antibody (ACCA) had the highest association with complications, ASCA and ACCA associated equally with the need for surgery. Although in most individual studies the combination of ≥2 markers had a better diagnostic value as well as higher association with complications and need for surgery, we found the combination performing slightly better than any individual marker in our meta‐analysis. (Inflamm Bowel Dis 2012)