The unequivocal documentation of visual and histological damage on the esophageal mucosa is the mainstay of decision-making when treating GERD. Endoscopic evaluation is of primary importance if a patient is suspected of having a shortened esophagus, and even more so in patients with a failed repair. Preferably the surgeon who will provide the treatment should perform or observe the endoscopic assessment. The identification of severe esophagitis or stricture usually presents no problem. Barrett's esophagus can only be documented with multiple biopsies and the histological identification of intestinal metaplasia in the columnar-lined esophagus. Multiple biopsies and brush cytologies are always needed to rule out malignancy if the esophagus is strictured. Esophageal dilatations, using bougies or balloon dilators, may be necessary to provide an esophageal lumen that will allow a proper examination while at the same time permitting easier food intake.
There are numerous esophageal mucosal damage classifications. They are evidence of the lack of reproducible interpretations among various endoscopists. The MUSE classification proposed by Armstrong et al.24 has the advantage of visually describing and quantifying the four types of mucosal damage that can be observed at endoscopy: metaplasia (M), ulcers (U), stricture (S), and erosions (E). This classification represents an effort to improve the objectivity of recording and scoring existing lesions.
This classification does not recognize observations that correspond to equivocal evidence of reflux damage, as mucosal hyperhemia. The initial observation by Allison25 that a fundamental difference exists between esophagitis in squamous mucosa and a columnar-lined mucosa is retained in this classification. The refluxate rarely produces deep damage in a squamous mucosa. In a columnar-lined mucosa, the refluxate causing esophagitis often is seen with deep penetration through the esophageal wall, occasionally resulting in periesophageal reaction and mediastinal fibrosis.
Esophageal biopsies should demonstrate the proven end result of reflux damage. Unfortunately, the endoscopic findings do not always tally perfectly with the histological assessment. Confirmation of esophagitis suggested by endoscopy is obtained in 32-72% of patients.26 Whether this poor correlation between visual documentation and histological evidence is attributable to sampling errors, to the patchy nature of esophageal inflammation, or simply to overinterpretation remains open to discussion. At present, unequivocal histological evidence of reflux damage includes: acute inflammatory reaction in the epithelium and subepithelium; erosions and ulcerations of the mucosa; a fibrotic stricture especially when associated with mucosal breaks; and histological documentation of a columnar-lined esophagus with incomplete intestinal metaplasia.
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