Jeffrey M. Marks

A Primer on Natural Orifice Transluminal Endoscopic Surgery: Building a New Paradigm

Access to the abdominal cavity is required for diagnostic and therapeutic endeavors for a variety of medical and surgical diseases. Historically, abdominal access has required a formal laparotomy to provide adequate exposure. Natural orifice transluminal endoscopic surgery (NOTES) is an emerging experimental alternative to conventional surgery that eliminates abdominal incisions and incision-related complications by combining endoscopic and laparoscopic techniques to diagnose and treat abdominal pathology. During NOTES, commercially available flexible video endoscopes are used to create a controlled transvisceral incision via natural orifice access to enter the peritoneal cavity. Common incision-related complications such as wound infections, incisional hernias, postoperative pain, aesthetic disdain, and adhesions could be minimized or eliminated by NOTES. NOTES has evolved from more than 2 centuries of technological innovations and continued growth in the field of surgical endoscopy. Innovative surgical endoscopists have slowly developed means to surpass the constraints of the gastrointestinal lumen by using a flexible endoscope. The future of surgical endoscopy may be the shared entity of NOTES, which further integrates endoscopy, gastroenterology, and minimally invasive and general surgery. Although the promise of NOTES is electrifying to surgeons and endoscopists, several key issues need to be characterized prior to the incorporation of NOTES into routine practice. This article reviews the status, contemporary body of literature, limitations, and potential future implications accompanying the development of NOTES.

PEG Rescue : a practical NOTES technique

Dislodged percutaneous endoscopic gastrostomy (PEG) tubes occur commonly and may require urgent surgical intervention in a susceptible patient population. Natural orifice translumenal endoscopic surgery (NOTES) may facilitate PEG rescue and avoid the morbidity associated with contemporary surgical techniques. We report a case of a dislodged PEG tube in the early post-operative period with evidence of incomplete gastrocutaneous tract formation and intra-abdominal leakage. Bedside transgastric NOTES exploration facilitated peritoneoscopy, evacuation of intra-abdominal fluid, and re-establishment of the PEG tube through the original gastrotomy tract. Tube feeds were resumed and postoperative contrast fluoroscopy demonstrated no intra-abdominal leakage from the replaced PEG tube. No postoperative complications related to the NOTES procedure were noted at 30 days of follow-up. PEG rescue represents a unique, practical, and empowering application of the burgeoning experience of NOTES.

FLS and FES: Comprehensive Models of Training and Assessment

The Fundamentals of Laparoscopic surgery (FLS) is a validated program for the teaching and evaluation of the basic knowledge and skills required to perform laparoscopic surgery. The educational component includes didactic, Web-based material and a simple, affordable physical simulator with specific tasks and a recommended curriculum. FLS certification requires passing a written multiple-choice examination and a proctored manual skills examination in the FLS simulator. The metrics for the FLS program have been rigorously validated to meet the highest educational standards, and certification is now a requirement for the American Board of Surgery. This article summarizes the validation process and the FLS-related research that has been done to date. The Fundamentals of Endoscopic Surgery is a program modeled after FLS with a similar mission for flexible endoscopy. It is currently in the final stages of development and will be launched in April 2010. The program also includes learning and assessment components, and is undergoing the same meticulous validation process as FLS. These programs serve as models for the creation of simulation-based tools to teach skills and assess competence with the intention of optimizing patient safety and the quality of surgical education.

Biliary stenting is more effective than sphincterotomy in the resolution of biliary leaks

AbstractBackground: Biliary fistulae may occur following surgical injury, abdominal trauma, or inadequate closure of a cystic duct stump. These leaks are most often managed by drainage of the associate biloma and either endoscopic sphincterotomy or placement of a biliary endoprosthesis to decrease the pressure gradient between the bile duct and the duodenum created by the muscular contraction of the ampullary sphincter. In a previous study, we demonstrated a statistically significant reduction in ductal pressures following stent placement as compared to sphincterotomy. The goal of this present study was to determine if reduction in ductal pressures correlates clinically with the resolution of biliary leaks in an animal model. Methods: Fourteen mongrel dogs underwent laparotomy, cholecystectomy without closure of the cystic stump, and a lateral duodenotomy to identify the major papilla. The dogs were then randomized into three groups. Group I (n = 5) was a control group undergoing closure of the duodenotomy only. Group II (n = 4) underwent sphincterotomy. Group III (n = 5) underwent placement of a 7 Fr × 5 cm biliary endoprosthesis prior to duodenotomy closure. A drain was placed adjacent to the cystic duct stump in all groups. Drain output was recorded daily. The biliary leak was considered resolved when the output was <10 cc/day. Regardless of suspected fistula closure, the drains were not removed until 2 weeks postprocedure. Necropsy was performed to identify undrained intraperitoneal bile. Statistical analysis was performed using Student’s paired t test. Results: All dogs had bile leaks identified on postoperative day 1. The number of days required for resolution of bile leak in group I (mean ± SEM) was 7.60 ± 0.87 days, as compared to 6.75 ± 0.80 days for group II and 2.60 ± 0.24 days for group III. There was no significant difference in the duration of bile leak between groups I and II (p= 0.445). Group III, however, had a significant reduction in the duration of biliary fistulae as compared to both groups I and II (p < 0.005). At autopsy, persistent bilomas were identified in 80% of group I, 25% of group II, and 0% of group III. None of the dogs showed evidence of dehisence of the duodenotomy closure site as a source of bile leak. Conclusions: Biliary stenting significantly reduces the time to resolution of cystic duct leaks as compared to sphincterotomy in a canine model. The results obtained in this study support the use of biliary endoprostheses in the management of biliary leaks and fistulae.

Natural orifice transluminal endoscopic surgery (NOTES) as a diagnostic tool in the intensive care unit

BackgroundAutopsy studies confirm that many intensive care unit (ICU) patients die from unrecognized sources of abdominal sepsis or ischemia. Computed tomography (CT) scans can be of limited use for these diagnoses and difficult to obtain in critically ill patients who require significant support for transport. Bedside laparoscopy has been described but still is cumbersome to perform. Bedside flexible endoscopy as a diagnostic tool or for placement of gastrostomy tubes is a standard ICU procedure. Natural orifice transluminal endoscopic surgery (NOTES) can provide access to the peritoneal cavity as a bedside procedure and may decrease the number of patients with unrecognized intra-abdominal catastrophic events.MethodsPigs were anesthetized and peritoneal access with the flexible endoscope was obtained using a guidewire, needle knife cautery, and balloon dilatation. The transgastric endoscope was used to explore all quadrants of the abdominal cavity. The small bowel was visualized to complete the exploration. The transgastric access location was then managed with the use of a gastrostomy tube. The animals were euthanized and analyzed.ResultsEight pigs were studied and complete abdominal exploration, including diaphragm visualization, was possible in all cases. Endoscopy-guided biopsies were performed, adhesions lysed, and the gallbladder successfully drained percutaneously. The small bowel was run successfully with percutaneous needlescopic suture graspers.ConclusionsThese animal studies support the concept that NOTES, with management of the gastric opening with a gastrostomy tube, may be another approach for finding unrecognized sources of abdominal sepsis or mesenteric ischemia in difficult ICU patients. These encouraging results warrant a prospective human trial to assess safety and efficacy.

Diaphragm pacing with natural orifice transluminal endoscopic surgery: potential for difficult-to-wean intensive care unit patients.

BackgroundUp to 50% of the patients in the intensive care unit (ICU) require mechanical ventilation, with 20% requiring the use of a ventilator for more than 7 days. More than 40% of this time is spent weaning the patient from mechanical ventilation. Failure to wean from mechanical ventilation can in part be attributable to rapid onset of diaphragm atrophy, barotrauma, posterior lobe atelectasis, and impaired hemodynamics, which are normally improved by maintaining a more natural negative chest pressure. The authors have previously shown that laparoscopic implantation of a diaphragm pacing system benefits selected patients. They now propose that an acute ventilator assist with interventional neurostimulation of the diaphragm in the ICU is feasible and could facilitate the weaning of ICU patients from mechanical ventilation. Natural orifice transluminal endoscopic surgery (NOTES) has the potential to expand the benefits of the diaphragm pacing system to this acute patient population by allowing it to be performed at the bedside similarly to insertion of the common gastrostomy tube. This study evaluates the feasibility of this approach in a porcine model.MethodsPigs were anesthetized, and peritoneal access with the flexible endoscope was obtained using a guidewire, needle knife cautery, and balloon dilation. The diaphragm was mapped using a novel endoscopic electrostimulation catheter to locate the motor point (where stimulation provides complete contraction of the diaphragm). An intramuscular electrode then was placed at the motor point with a percutaneous needle. The gastrotomy was managed with a gastrostomy tube.ResultsFour pigs were studied, and the endoscopic mapping instrument was able to map the diaphragm to identify the motor point. In one animal, a percutaneous electrode was placed into the motor point under transgastric endoscopic visualization, and the diaphragm could be paced in conjunction with mechanical ventilation.ConclusionsThese animal studies demonstrate the feasibility of transgastric mapping of the diaphragm and implantation of a percutaneous electrode for therapeutic diaphragmatic stimulation.

Complete endoscopic closure of gastrotomy after natural orifice translumenal endoscopic surgery using the NDO Plicator.

BackgroundThe NDO Plicator is a device developed for endoscopic treatment of gastroesophageal reflux disease (GERD) by approximation of tissues together with a double-pledgeted U-stitch. It was theorized that this device may facilitate transgastric natural orifice translumenal endoscopic surgery (NOTES) because closure of the transgastric defect remains a key component for advancement of this new technology.MethodsA standardized 12-mm gastrotomy was created endoscopically in four pigs using a combination of needle-knife cautery and balloon dilation. As the endoscope was removed, a Savary soft-tipped wire was introduced into the stomach, and the NDO Plicator was subsequently advanced over the wire. Each defect was identified, and the device was positioned. If necessary, the Plicator’s tissue grasper was used to hold the superior aspect of the gastrotomy and bring the opposed borders of the defect within the jaws of the device. The device was fired three times, leaving three pledgeted suture bundles to close the gastric defect. After closure, each animal was explored, and the integrity of the closure was assessed. The animals underwent in vivo contrast fluoroscopy and ex vivo burst pressure testing studies for assessment of leakage at the closure site.ResultsThe first animal was used to test feasibility, refine techniques, and develop a standard procedure. All of the next three animals studied showed complete sealing of the gastrotomy site without evidence of contrast extravasation on multiplanar fluoroscopic imaging. Each stomach was excised, submerged in water, and subjected to a pressurized air leak test. No leaks were noted until pressures exceeded 55 mmHg.ConclusionThis study supports the use of the NDO Plicator for closure of standardized gastric defects in a porcine model. In addition to closing NOTES gastrotomies, the NDO Plicator may be a particularly useful tool for obtaining complete closure of gastric perforations and anastomotic leaks, and for performing stomal reduction after gastric bypass procedures. The mechanical properties of a closure are not the only factor determining whether a leak will develop. Tissue opposition, ischemia, and tension are important factors that are not easily or reliably measured. The physiologic relevance of gastric bursting pressure is not known. Therefore, corollary animal studies with longer-term evaluation are necessary before research proceeds to clinical trials.

Late phase TNF-alpha depression in natural orifice translumenal endoscopic surgery (NOTES) peritoneoscopy

BACKGROUND Natural orifice translumenal endoscopic surgery (NOTES) allows access to the peritoneal cavity without skin incisions. Contamination of the peritoneal cavity by enteric contents may render NOTES more physiologically and immunologically invasive than previously thought. Measurement of interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) is a validated method to quantify surgical stress. The physiologic and immunologic impact of NOTES is unknown. METHODS A total of 37 swine underwent abdominal exploration via transgastric NOTES peritoneoscopy, laparoscopy (LX), laparotomy (OPEN), or sham surgery (CONTROL) and were allowed to survive. TNF-alpha, IL-1beta, and IL-6 plasma levels were determined at the start and completion of surgery, and at 1 hour, 2 days, and 14 days postoperatively. RESULTS At surgical completion, OPEN animals demonstrated higher TNF-alpha levels than all groups. TNF-alpha levels were similar for all groups at 1 hour and 2 days. NOTES animals had significantly reduced plasma levels of TNF-alpha than all other groups on postoperative days 7 and 14. Controlling for baseline cytokine variability, analysis was repeated using normalized data, which confirmed significantly reduced TNF-alpha levels for NOTES compared with all groups at 14 days. Subset analysis excluding LX and OPEN complications revealed lower NOTES TNF-alpha levels at 7 and 14 days compared with all groups. IL-1beta and IL-6 levels were undetectable in 66.8% and 70.5% of samples, respectively, without significant trends. CONCLUSIONS Diagnostic NOTES peritoneoscopy demonstrated similar levels of systemic proinflammatory cytokine TNF-alpha compared with diagnostic laparoscopy and exploratory laparotomy in the immediate postoperative period despite gross intraperitoneal contamination. None of the surgical groups, however, produced a measurable, consistent trend in IL-1beta or IL-6. Consistently reduced levels of TNF-alpha in NOTES animals in the late postoperative period indicates an immunomodulatory effect of the NOTES surgical technique not present in laparoscopy or laparotomy.

Cost analysis of diagnostic laparoscopy vs laparotomy in the evaluation of penetrating abdominal trauma

AbstractBackground: Diagnostic laparoscopy for the evaluation of injuries in patients with penetrating abdominal trauma has been shown to decrease the morbidity and mortality associated with mandatory laparotomy. The overall impact on patient care and hospital costs has not been thoroughly investigated. The goal of this study was to determine the economic impact of laparoscopy as a diagnostic tool in the management of patients following penetrating trauma to the abdomen or flank. Methods: Retrospective chart review of all hemodynamically stable patients with penetrating trauma to the abdomen or flank, but without other injuries requiring emergent intervention, admitted to a level I trauma center between January 1, 1992, and September 30, 1994. Those patients who underwent either laparoscopy (DL) or laparotomy (NL) or both (CONV) and who had no intraabdominal organ injuries requiring surgical therapeutic intervention were included in the study. Age, operative time, operative findings, length of hospitalization, Injury Severity Score (ISS), variable costs, and total costs were recorded for each patient. Results: Fourteen patients underwent negative/nontherapeutic laparoscopy (DL), 19 patients underwent negative/nontherapeutic laparotomy (NL), and four patients underwent both laparoscopy and laparotomy, a conversion procedure (CONV). There was no significant difference in age, operative times, or ISS between the DL and NL groups. Mean ISS of CONV patients was significantly greater than that of DL patients, 5.75 ± 1.97 vs 2.43 ± 0.63 (p < 0.05). Mean operative time for CONV patients was also significantly greater than both DL and NL patients, 106.5 ± 17.00 min vs 66.1 ± 6.55 and 47.3 ± 7.50 min, respectively (p < 0.05). The mean length of stay was significantly shorter in the DL group as compared to the NL or CONV groups, 1.43 ± 0.20 vs 4.26 ± 0.31 and 5.0 ± 0.82 (p < 0.0001). The variable costs for the DL group were significantly lower than those incurred by patients in the NL and CONV groups,

Oral allopurinol does not prevent the frequency or the severity of post-ERCP pancreatitis.

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