As a center of endoscopic excellence with a robust research-based clinical practice, Mayo Clinic is leading endoscopic innovations. Three clinical highlights of these advances are direct endoscopic necrosectomy, natural orifice transluminal endoscopic surgery (NOTES), and endoscopic treatment of Barrett's esophagus.
Severe acute pancreatitis is life-threatening. It frequently requires stays in intensive care units for days or weeks and often disrupts the pancreatic duct. Over several weeks solid necrotic pancreatic tissue collects, intermixed with pancreatic juice. If this collection becomes infected or becomes large enough to cause outlet obstruction, drainage is warranted.
Conventional treatment is an open or, more recently, laparoscopic necrosectomy to drain the cavity and debride the solid material. Open surgical drainage has notable drawbacks.
"Often a very large and difficult operation is required, because the area that needs debridement is located behind the stomach and multiple operations may be required. The patient is often left with large scars, external drains, and subsequent fistulas," explains Todd H. Baron, M.D., an interventional endoscopist and director of pancreaticobiliary endoscopy at Mayo Clinic. "We knew there had to be a better way."
By 2005, a Mayo Clinic team refined a nonsurgical approach that is in use today — direct endoscopic necrosectomy. The Mayo team passes an endoscope inside the stomach or the duodenum and then punches through the gastric or duodenal wall to create a tract to the inside of the cavity. The tract is enlarged up to 20 mm in diameter. The endoscope is then passed directly into the cavity to debride the solid material, depositing it in the stomach or duodenum for normal evacuation.
Between 3 and 5 procedures are typically needed to eliminate all the necrotic material. The first procedure is usually performed in the hospital, with 1 day of observation. Subsequent debridements are performed as outpatient procedures.
In fall 2009, the gastrointestinal endoscopic surgical team ushered in a new era of surgery at Mayo Clinic: scarless, pain-free, natural orifice transluminal endoscopic surgery (NOTES.) See Figures 2A, 2B, 2C and 2D for more information.
NOTES eliminates the skin wounds of open and laparoscopic procedures by using natural anatomic passages for access, such as the vagina and anus, and by working with a new generation of endoscopic tools. Two new NOTES protocols have been approved by the Mayo Clinic Institutional Review Board: transvaginal cholecystectomy and emergency repair of ulcers. The transvaginal cholecystectomy will be introduced first.
Research into the tools, techniques, and physiologic responses has been ongoing for years. Two NOTES clinical trials are now enrolling patients, according to gastroenterologist Christopher J. Gostout, M.D., of Mayo's Developmental Endoscopy Unit:
Explains Dr. Gostout, who is also director of training and technology for the American Society for Gastrointestinal Endoscopy.: "At Mayo Clinic we are fortunate to have the Developmental Endoscopy Unit for advancing NOTES. This specialized unit has allowed a range of surgical subspecialties to interact in cadaver laboratories and on animal models — including surgeons from gynecologic oncology, urology, and general surgery, as well as research engineers. We feel we have a dream team of multidisciplinary expertise."
NOTES procedures have been done experimentally at several advanced centers in Europe and the United States with encouraging results.
Esophageal adenocarcinoma arising from Barrett's esophagus is increasing faster than any other cancer in the United States and the tumors are lethal, with 90 percent of patients dying within 5 years of diagnosis.
Etiology is linked to the common problem of gastrointestinal reflux. Traditionally open surgical esophagectomy has been the treatment of choice for patients with Barrett's esophagus with early cancers and high-grade dysplasia. Recently, Mayo Clinic gastrointestinal specialists have come to favor endoscopic therapies. Endoscopic mucosal resection is now routinely performed on an outpatient basis at Mayo, and data demonstrate that it is a highly cost-effective, less-invasive, and tissue-sparing approach for cases of early cancer. This allows gastroenterologists to obtain tissue and staging. Published results show it offers equivalent outcomes to open surgery.
"The endoscopic approach is an effective outpatient alternative management strategy for high-grade dysplasia and early-stage cancer. We have almost 4 years' worth of cancer follow-up data that show approximately equivalent outcomes. We think these patients can be much better treated endoscopically, with much less trauma, time, and expense," explains Kenneth K. Wang, M.D., director of the Barrett's Esophagus Unit at Mayo Clinic and expert in endoscopy therapies for this disorder.
The Mayo Clinic team is advancing management of Barrett's esophagus through such technically demanding innovations as removing larger and more deeply penetrating tumors. In the past, elevated tissues were the surgical target. Today, Mayo Clinic performs more flat tissue removal than any other US center. Its success with endoscopic removal of cancers and high-grade dysplasia is leading to creation of a full-thickness resection. Endoscopic submucosal dissection, which has been used successfully in Asia, is also being investigated.