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Natural Orifice Transluminal Endoscopic Surgery
From the 3rd Annual University of California, San Diego, School of Medicine
The goal of this program is to provide tools to aid the decision-making process (especially in regard to ethical and technical questions and challenges) associated with adoption of natural orifice transluminal surgery (NOTES). After hearing and assimilating this program, the clinician will be better able to:
1. Explain ethical concerns surrounding the adoption of any new medical technique.
2. Recognize ethical principles protecting human participants in clinical research.
3. Discuss the knowledge base required of surgeons and gastroenterologists who are interested in learning to perform NOTES.
4. Identify the indications for and benefits of mediastinal access.
5. Apply research findings on transgastric access to the peritoneum, cross-contamination, and the incidence of infectious complications in surgical practice.
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning committee to disclose relevant financial relationships within the past 12 months that might create any personal conflicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, the following has been disclosed: Dr. Ponsky is a consultant for US Endoscopy. Dr. Gostout is an advisor for, has equity in, and has received research support from Apollo Endosurgery; Dr. Gostout has also received research support from Olympus Tokyo. Dr. Hazey has received educational and/or research support from Boston Scientific, Ethicon, and Stryker. Dr. Easter and the planning committee reported nothing to disclose.
This program was recorded at 3rd Annual University of California, San Diego Hands-On NOTES and Single Site Surgery Symposium, held November 19-21, 2009, in San Diego, CA, and sponsored by the UCSD School of Medicine. The Audio-Digest Foundation thanks the speakers and the UCSD School of Medicine for their cooperation in the production of this program.
Ethics of NOTES Operations
David Easter, MD, Professor of Clinical Surgery, Division of Minimally Invasive Surgery, University of California, San Diego, School of Medicine
Hypothesis: natural orifice transluminal endoscopic surgery (NOTES) will replace many minimally invasive and laparoscopic procedures
Cautionary comments: “new is assumed to be better”; clinicians often under pressure to adopt latest techniques prematurely; many procedures showing great promise end up as “spectacular failures”; examples — laser laparoscopic cholecystectomy; cryotherapy for hemorrhoids (associated with severe mucositis); nephrectomy for childhood nephroblastoma (more children harmed than helped); arthroscopy for knee pain (did not diminish pain)
Spectacular clinical successes: often embraced despite lack of randomized clinical trials (eg, laparoscopic cholecystectomy, coronary artery bypass grafting)
Current dilemma: whether NOTES approach should be applied to such high-volume procedures as percutaneous endoscopic gastrostomy or transmucosal endoscopic resections
Choice of procedure: often based on clinical observation, inference (understanding of biology involved), and experience (surgeon’s capabilities and patient’s preferences)
Equipoise: not known whether new technique or intervention superior to older one; studies should not be done if each option not equally likely to be better
Factors in acceptance by surgeons: compatibility with existing practice; easy to provide; similarity to existing practice; applicable to high-volume procedures; appealing to patients; economical to learn and adapt; aggressive promotion to patients and surgeons; benefits must be perceived by all stakeholders; quality of life and cost-benefit data must be persuasive
Ethical considerations: practice — designed to enhance patient well-being; research — tests hypotheses; experi-mentation — research on new and untested entity; all may occur simultaneously, but all have different sets of rules; public law signed in 1974 led to formation of national commission for protection of human research subjects; resulted in publication of Belmont Report outlining principles of and guidelines for ethical research on humans; addressed blurring of boundaries between practice, research, and experimentation (risk-benefit analysis different in research and conventional clinical practice; must follow guidelines; informed consent differs for each)
Basic ethical principles described in Belmont Report: respect for patients’ autonomy (patient must consent to participate in research); nonautonomous persons (eg, prisoners, children) need special protections against exploitation; do no harm; maximize benefits and minimize risks
Informed consent: full and complete disclosure of all details; more detailed for research than for clinical practice; patient must be able to understand concept of clinical trials; participation must be voluntary
Subject selection: must incorporate justice; consider source of funding and who will benefit (ie, what is driving research)
Levels of evidence: meta-analysis — analysis of well-designed clinical trials; when evidence lacking or confusing, organizations such as Rand Group and Cochrane Collaboration provide expert opinions or database of reviews
NOTES: A Training Paradigm
Jeffrey L. Ponsky, MD, Oliver H. Payne Professor and Chair, Department of Surgery, and Surgeon in Chief, University Hospitals, Case Western Reserve University School of Medicine, Cleveland, OH
Necessary knowledge base: gastrointestinal (GI) physiology and pathology; gross anatomy, including basic GI structures and normal and abnormal GI anatomy; abdominal, pelvic, and thoracic anatomy; basic and advanced endoscopic diagnostic and therapeutic techniques; open as well as laparoscopic surgical techniques
Clinicians learning NOTES procedures: general surgeons and gastroenterologists; some urologists
Gastroenterologists: train for 3 yr in internal medicine, followed by 3-yr gastroenterology fellowship, then one additional year of advanced GI (endoscopy) training; knowledge of GI anatomy superficial (cannot find ligament of Treitz, fold of Treves, or Meckel’s diverticulum); know GI physiology, pathology, and medical management of GI disease; understand subtleties of endoscopic anatomy and pathology; also understand endoluminal diagnosis and therapy
General surgery residents: train for 5 yr in general surgery, followed by 1-yr fellowship in laparoscopic or minimally invasive surgery; learn abdominal as well as GI anatomy, GI physiology and pathophysiology, and open and laparoscopic surgical techniques; also learn preoperative and postoperative care (third-space losses, fluid shifts, critical care, management of surgical complications, and basic endoscopic technique)
Knowledge needed for NOTES: clinician should understand relationships among anatomic structures of abdomen; must also understand variations in normal anatomic structures and relationships; gastroenterologists more accustomed to examining endoscopic ultrasonography (reveals area outside organ of interest; ordered by surgeons, but not used to full potential); example — surgeons know how to drain pancreatic pseudocyst or necrosis endoscopically (through stomach wall); may not realize that NOTES permits entry into lesser sac to see pancreas and diagnose problems; if fluid necessary, can use endoscopic ultrasonography to inject saline into lesser sac; permits puncture of normal lesser sac to study pancreas; combination of GI skills and good surgical skills better than either alone
Training: simulation technology will provide opportunity for repeated practice and help train next generation of surgeons; gastroenterologists — may recognize structures or conditions in GI tract that surgeons do not recognize; in addition to usual training, practicing performance of open and laparoscopic abdominal surgery (to learn variations in anatomy) would be beneficial; general surgeons — in addition to usual advanced training, should spend time with gastroenterologists learning advanced techniques, particularly endoscopic mucosal resection and endoscopic ultrasonography; speaker expects that in future, NOTES interventionalists will be trained for 3 yr in general surgery, plus additional 3 yr in advanced GI training (rather than current practice of surgeons and gastroenterologists working together on NOTES)
NOTES: Transesophageal Surgery?
Christopher J. Gostout, MD, Professor of Medicine and Director, Developmental Endoscopy Unit, Mayo Clinic College of Medicine, Division of Gastroenterology, Rochester, MN
Why go through mediastinum: provides easy access and flexibility; permits use of flexible endoscope for exploration and (perhaps) intervention; allows access to heart, lungs, and hilar and mediastinal lymph nodes
Cardiac indications: initially, used to gain access to and remove blood clots tied to atrial fibrillation; maneuvers performed by cardiologists and interventional radiologists require subcostal access and intravascular intervention; conventional ablation procedures associated with risk for fatal esophageal fistula; endoscope can monitor and possibly prevent complication
Other indications: thoracic sympathectomy; device placement
How to perform procedure: direct esophagotomy or offset access (submucosal endoscopy with mucosal flap [SEMF] method)
Potential complications: tension pneumomediastinum; infectious mediastinitis; collateral damage due to tight working space
Submucosal endoscopy with mucosal flap: purpose to isolate mucosa from submucosa and create working space; delamination easy in esophagus (allows surgeon to effectively tunnel into submucosal space); balloon dissection method proving more accurate and appropriate for esophagus than high-pressure CO2; effective working length of »10 cm allows offset entry; closure simpler than with direct esophagotomy because overlying mucosa can serve as patch for exit point; close entry point with standard hemostatic clips
Technique: create small fluid bleb to isolate submucosa; inject hydroxypropylmethylcellulose to preserve gas; mucosa now separated from muscle layer; endoscopic retrograde cholangiopancreatography (ERCP) stone retrieval balloon then placed into space, inflated, and advanced down esophagus; eventually increases opening of entry point to accommodate endoscope; to learn technique, draw muscle into endoscopic mucosal resection cap and excise full-thickness muscle layer to gain entry into mediastinum; requires 2-cm myotomy; thought to be safer than using needle knife; opening large enough to place endoscope without creating collateral damage to surrounding structures (unlike cutting through esophageal wall with needle knife); SEMF thought to provide safe multisite access for NOTES in stomach, rectum, or colon, as well as excellent access to mediastinum; currently entering clinical practice for performing achalasia myotomies
Enabling technologies: space is confined; endoscope acceptable for lymph node sampling, but offset entry with 10-cm tunnel necessary to access heart; conceptual changes may be required for redesign of endoscope; safer SEMF access under development; ensure submucosa isolated; fluid bleb cut open with needle knife; ERCP balloon creates risk for perforation; instead, insert tunneling balloon, which can create space 2 cm in diameter; closure — full-thickness closure required for direct esophagotomy; special suturing device that mimics GI-curved needle fits on tip of endoscope (requires 2-channel endoscope); transfer needle tip for suture reloading and placement of second stitch; confined space makes procedure “ripe for robotics”
Conclusion: transesophageal mediastinoscopy feasible and safe; first applications include cancer staging, achalasia myotomy, and device placement; »12 human achalasia myotomies performed to date (mostly in Japan and Venezuela); human feasibility studies needed
Bacterial Contamination and Diagnostic Utility of NOTES
Jeffrey W. Hazey, MD, Associate Professor of Surgery, Center for Minimally Invasive Surgery, the Ohio State University College of Medicine, Columbus
Background: NOTES originated almost 30 yr ago (eg, for percutaneous endoscopic gastrostomy tubes, pancreatic necrosectomies); recent innovations mostly in methods for accessing peritoneum; depends on reason for access (visualization, extraction, or instrumentation)
Diagnostic uses of NOTES
Bacterial contamination with transgastric access: growing body of evidence suggests that problems result from pathophysiology, rather than from perforation of organ (eg, gastric ulcer may promote ongoing contamination); speaker and colleagues studied 50 patients undergoing gastrotomy Roux-en-Y gastric bypass without sterilization of gastric contents; cross-contamination documented in only 5 patients (2 of 5 organisms nonpathogenic in healthy adults); no infectious complications occurred; another study evaluated whether peritoneum could be safely accessed transgastrically, and whether technique effective for staging abdomen; could be used for cancer, trauma (penetrating injuries), and other conditions requiring exploratory laparoscopy; sterile environment and specialized equipment not necessary (could be performed in field); performed preliminary study of 10 patients undergoing staging laparoscopy for mass on pancreatic head; patients also underwent separate transgastric endoscopic diagnostic peritoneoscopy (endoscopist blinded to laparoscopic findings); endoscopic and laparoscopic findings correlated in 9 of 10 patients; study then extended to 10 more patients; included data on bacterial contamination; laparoscopic and endoscopic findings correlated in all patients; peritoneal washings yielded <33 colony-forming units (CFU)/mL after endoscopic exploration; no associated infectious complications; all peritoneal access procedures now performed blindly (no ultrasonography); endoscopy provides better view of abdominal cavity and wall than laparoscopy
Transgastric access to peritoneum without laparoscopic visualization: studied 40 patients (10 preinsufflation, no previous surgery; 10 preinsufflation, with previous surgery; 10 without preinsufflation, no previous surgery; 10 without preinsufflation but with previous surgery); access successful in all cases (no complications); detected 9 occult umbilical hernias and 1 occult inguinal hernia not diagnosed preoperatively; also found one paraesophageal hernia; 4 patients underwent endoscopic adhesiolysis (no complications); cross-contamination documented in 9 of 39 patients, but no infectious complications
Insufflation: study saw correlation between endoscopic insufflation and laparoscopic insufflation (without use of laparoscopic visualization); endoscopic insufflation accomplished using biopsy channel and standard laparoscopic insufflator
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