The last five years has seen several advancements in technology available to gastroenterologists and other physicians in the management and diagnosis of digestive diseases. What follows are short updates on some of the more interesting new technologies now available in Jacksonville.

Overview of Current Video Endoscopy

Endoscopy has revolutionized over the last 30 years. The history of modern endoscopy originated with the introduction of fiber optic material used during the Second World War for aircraft instrument panels. Fiber optic cabling allowed the transition of light over a long passage of space. Early pioneers of endoscopic design utilized this principle along with the added benefit of using separate bundles attached with a lens and optic viewer to construct the first prototype endoscope. These two features of fiberoptic technology along with added steering cables allowed the commercial development of the flexible fiberoptic scope. In the late 70's came the introduction of the mini micro video chip and the evolution of flexible optic endoscopes into flexible video endoscopes. Today, in Jacksonville, most institutions have third generation video endoscopes which allow magnified, crystal clear video images of the lumen of the digestive tract. In addition to the ability to directly visualize what is being seen, endoscopes have operating channels that allow the passage of biopsy forceps, cautery devices, snare devices and most recently new suturing devices being utilized in the plication of gastric folds in reflux surgery.

The future of endoscopy will soon yield endoscopes that can magnify almost to a cellular level, allowing the endoscopist to analyze directly the mucosa, such as to identify dysplasia. In addition, tissue chromatography is under intense study with dozens of publications this year. This is a technique in which a dye is sprayed through the working channel of the endoscope onto suspected tissue and, depending upon its fluoroscopic appearance, malignant tissue can be identified.

Minimally Invasive Gastrointestinal Procedures for GERD

In the last three years, the United States Food & Drug Administration has approved for use two devices allowing the endoscopist to treat gastroesophageal reflux (GER). Each of these devices allows a physician to correct the acid-reflux disorder with an outpatient procedure that does not require general anesthesia.

The first approach is the EndoCinch. This suturing apparatus is attached to the tip of an endoscope in order to place sutures just below the gastroesophageal (GE) junction. Multiple sutures are placed to pull together the folds of the upper stomach, creating fundoplications which resemble "speed bumps" that reduce the tendency of fluid in the stomach to reflux up into the distal esophagus (Images 1-4). The EndoCinch device has been used successfully by Jacksonville physicians since early 2001.
 

We are now beginning to know the long-term costs and benefits of this procedure. In May, 2002, at the Digestive Disease Week (DDW) meetings in San Francisco, Dr. Chen et al. presented the data from 183 patients who underwent endoluminal fundoplication. The average cost of care per patient in the year prior to the procedure was $2379 for pharmacotherapy, hospital visits and physician care. In the year after the procedure, the cost fell to $351.00, a saving of $2208.00 per patient. Certain patients required a second procedure to be performed for improved clinical efficacy. The complications were minor with four patients having minor mucosal injury, five patients having bleeding that was managed endoscopically, and two patients developing dysphagia (difficulty swallowing) lasting several weeks. The conclusion of this study is that patients are very satisfied with this procedure, at least in the first year. In addition, there appears to be a substantial cost savings because of complete or partial elimination of prescription medications.

A second paper presented in May, 2002, by Dr. Abou-Rebyeh, described 16 patients who underwent endoscopic fundoplication for reflux symptoms. In this study, esophageal reflux scores were measured before and after the treatment. The authors found a significant reduction in symptoms and reflux medication use after fundoplication.

As is the case with most new technologies, we still lack head-to-head comparisons to more traditional therapies, such as surgical laparoscopic Nissen fundoplication. In a very preliminary study by Zahid Mahmood et al. presented this year, 18 patients were randomized to undergo endoscopic suturing and 16 underwent laparoscopic fundoplication. Following treatment, both groups required less reflux medication though based upon physiologic testing as measured by 24hr esophageal pH monitoring, the surgical group had better outcomes.

Endoscopic fundoplication is a technology that is now available. Its technical requirements are somewhat laborious and specialized training is required. In time, with perfection of this technology and more importantly with long-term trials, this may very well become a reasonable approach to treating patients with reflux symptoms and may very well diminish the need for long-term pharmacotherapy. What is required are long-term clinical trials comparing issues of cost compared to other forms such as traditional Nissen fundoplication, and other new technologies as described below.

The second new technology is the Stretta device. This is a catheter which is placed through the mouth into the esophagus to the level of the GE junction. There the device is activated to emit a radiofrequency that causes a controlled thermal injury to the muscular layers of the esophagus. The injury heals to leave scar tissue in the wall of the esophagus. This scar increases the barrier function at the lower esophagus to decrease GE reflux (Images 5 & 6).

Several papers were presented at this year's Digestive Disease Week in San Francisco on the Stretta technology. Dr. Corley et al. looked at 54 patients who had enrolled at eight centers of which 34 patients underwent active radiofrequency and 30 patients underwent sham radiofrequency therapy. At six months, the radiofrequency procedure significantly improved the heartburn symptoms and the utilization of proton pump inhibiters compared with patients who underwent the sham procedure. Interestingly, 24 hour esophageal monitoring pH scores were not significantly significant improved with radiofrequency treatment compared to sham procedures.

Another paper at this year's DDW on the Stretta radiofrequency procedure was presented by Dr. Wolfsen (Mayo Clinic, Jacksonville, FL) who reported the results from a study involving 590 patients at 33 medical centers. Dr. Wolfsen concluded that the procedure significantly improves gastroesophageal reflux symptoms and is superior to medication therapy. In his study, most patients were off of all antisecretory therapy at follow-up.

As with endoscopic suturing, we still need multicenter, long-term follow-up studies to understand the costs, benefits and risks of the Stretta radiofrequency. As such, long-term follow-up is still needed before we can conclusively suggest that one procedure is superior to the other.

Still considered experimental are endoscopic methods of injecting substances into the esophageal wall at the level of the LES to induce a scar. Several papers again were presented at this year's DDW meetings and, as of yet, there has been no FDA approval of any specific infusion. Interestingly, Donnelley et al. reported one attempt in this area ten years ago and concluded that this form of therapy would not be useful.

Virtual Colonoscopy (VC)

Virtual colonoscopy (VC) is the technology using computerized tomography x-ray scanning (CT scan) or magnetic resonance imaging (MRI) to obtain images of the colon to detect precancerous lesions such as adenomatous polyps. The theory behind virtual colonoscopy is to find a technology that could screen the colon without the need for invasive tests such as colonoscopy. This might be more acceptable to patients, improve compliance with colorectal cancer screening guidelines, and lower the incidence of procedural complications. The current commercially available devices use helical or spiral CT scanners with specialized software. The digital data collected by the helical or spiral CT is then transferred into a software platform to be which reconfigured as two-dimensional and three-dimensional images for review by the physician.

To date, published studies which together involve fewer than 500 people indicate a sensitivity of 90-92% for the detection of 1cm colonic polyps, when compared to standard colonoscopy. This failure to detect approximately 10% of significant lesions is unacceptable in the United States. Virtual colonoscopy should not be recommended as an alternative to endoscopic colonoscopy.

In Jacksonville, VC is offered by one for-profit vendor but not by any medical center. As of last year, during the third annual international meeting of virtual colonoscopy held in Boston, Massachusetts, there was very little agreement amongst major medical centers doing research in virtual colonoscopy with respect to issues of physician training, the bowel clean-out required, and many technical issues. Once these hurdles are overcome, long-term clinical outcome studies will be required. Still, virtual colonoscopy may eventually replace colonoscopy as a routine screening for individuals considered at low risk to develop colorectal cancer.

The Video Capsule That You Swallow

Recently, Jacksonville has seen the introduction of the video capsule. This small capsule, the size of a large antibiotic capsule, is a radio transmitter with a video chip, battery, and light source. It is swallowed with a glass of water and as it passes through the intestinal tract the capsule emits a radio signal which is recorded by a monitor worn by the patient. The capsule provides a limited view of the small intestine, but can provide remarkable images of small intestinal vascular lesions and tumors. The current model allows inspection of the small bowel in just one direction, offers no ability to be steered, and does not suggest the location lesions seen. Review of the images by the physician can require one hour or more. The capsule has no role in colon imaging at this time.

At present, the capsule seems to be best suited for patients who have bleeding of obscure origin of the digestive tract; specifically, bleeding felt to come from the GI tract somewhere within the small bowel. It is considered for patients with anemia and with Hemoccult-positive stool tests when both upper and lower endoscopy have failed to demonstrate a lesion. A significant number of papers on the video capsule demonstrating its efficacy in detecting small bowel pathology were presented at this year's GI meetings.

Small Intestinal Endoscopy

It would be ideal to be able to reach the entire small bowel with an endoscope. This would permit precise localization as well as the possibility of therapy, neither of which is possible with the video capsule. One such technology which has been available for several years is the small intestinal "push" endoscope. This is essentially a very long upper endoscope, which can usually achieve visualization into the mid portion of the jejunum. Another approach is to use an extremely long, "ultra thin" endoscope which is ingested and allowed to pass down through the digestive tract over several hours. After radiological assessment suggests that the ultra thin has reached near the end of the ileum, the scope then is slowly withdrawn over a period of time with the endoscopist looking through the endoscope. Both of these modalities have their limitations; they are time-consuming, expensive, and offer few therapeutic options.

The final option for small bowel endoscopy is intraoperative endoscopy. This is performed in an operating room with the patient under general anesthesia. An endoscope is inserted into the bowel by the surgeon passed through the small bowel manually while the gastroenterologist views the image. Intraoperative endoscopy is the last resort procedure to be considered in situations of severe recurrent bleeding.

MRCP versus ERCP

Magnetic resonance imaging (MRI) of the GI tract has come of age. Initially, the utilization of MRI in digestive diseases was limited. In the last several years, with refinement of technology both with respect to magnet and software, we are able now to look at areas of the digestive tract with increased sensitivity and specificity. MRI is becoming the procedure of choice for the imaging of hepatic masses and, in some cases, of the bile ducts. MRI can differentiate benign hemangiomas from other types of hepatic lesions.

Magnetic resonance cholangiopancreatography (MRCP) using T-2 weighted software has allowed the radiologist to see images of the bile ducts that are almost comparable to endoscopic retrograde cholangiopancreatography (ERCP). The advantages are that MRCP is a non-invasive procedure in that a patient does not require intubation with an endoscope and the added risk of pancreatitis, bleeding, perforation and sedation that can occur with ERCP. MRCP's limitations are that if pathology is seen, ERCP may be needed for therapy. MRCP demands significant new expertise from the radiologist which is not yet available at many centers. Irrespective, MRCP is currently the procedure of choice for some patients may replace the need for diagnostic ERCP in the future.

In a paper that has been submitted for presentation at this year's American College of Gastroenterology meeting, the Borland-Groover Clinic (Jacksonville, FL) looked at the impact of MRCP which has been performed here for approximately two years. We found a slight decrease in the use of diagnostic ERCP as compared to therapeutic ERCP since MRCP became available (Figure 1). MRCP is being ordered by gastroenterologists, surgeons and primary care physicians.

 

Endoscopic Ultrasound (EUS) Endoscopic ultrasound (EUS) is has been available in the United States for over 10 years and has been available in Jacksonville for approximately eight years. An endoscopic ultrasound that has attached to its tip an ultrasound probe which allows the gastroenterologist to record simultaneous ultrasound and visual images of the intestinal tract. EUS allows the physician to look just beyond the surface of the mucosa to see layers deeper to the mucosa and structures that surround the intestinal tract. This is an ideal way to stage many benign and malignant tumors of the gastrointestinal tract, especially esophagus, stomach, biliary, pancreatic and rectal. It is more sensitive than CT scanning for the staging of esophageal cancer and rectal cancers. More interesting though is its application extra-luminally. Endoscopy ultrasound is now being employed to look at lymph nodes surrounding the digestive tract to determine whether malignancies have spread to the lymph node system.

Figure 1. Diagnostic ERCP use has declined since the introduction of MRCP in 2000.

Figure 2: Use of Endoscopic Ultrasound (EUS) by the Borland-Groover Clinic, 1994-2000.

 In addition, some EUS systems employ a working channel through which needle biopsies and aspiration cytology can be obtained under real-time EUS guidance. EUS is useful for the aspiration and drainage of pancreatic pseudocysts, in the diagnosis of pancreatic cancer, and in the management of chronic pancreatic pain by injecting anesthetic into the celiac plexus under EUS guidance.

Three Jacksonville hospitals provide full EUS capability. Its use has increased rapidly since 1999 with the introduction of the linear endoscopic ultrasound and fine needle aspiration (FNA) which allow therapeutic options such as fine needle aspiration, celiac blocks, and pseudocyst drainage. Figure 2 presents the Borland-Groover Clinic's experience over seven years.

Conclusion

Technology is ever evolving in gastroenterology with respect to its procedures and imaging modalities. We are fortunate that Jacksonville has become a regional center of excellence keeping pace with the rest of the United States by offering the latest equipment, expertise, and innovations.

 June/July, 2002/ Jacksonville Medicine