High-resolution Video Endoscopy Research Articles

Advanced Imaging in the Diagnosis of Gastric Intestinal Metaplasia: The Expert's Approach

Gastric intestinal metaplasia (IM) is associated with a risk for development of differentiated-type gastric cancers. The diagnosis of IM is currently based on the histology of biopsy specimens because IM usually appears in flat mucosa and has few morphologic changes, and identification of IM by conventional endoscopy has high interobserver variability and a poor correlation with histological findings. Autofluorescence imaging (AFI) produces real-time images from natural tissue fluorescence from endogenous fluorophores with light excitation. Narrow band imaging (NBI) uses two specific narrow banded lights (400–430 nm and 525–555 nm) to accentuate the contrast in surface structure and microvascular architecture of the superficial mucosa. With magnification, NBI enables a detailed observation of the morphological features of the epithelium corresponding to histology. Currently, AFI and NBI are incorporated with high-resolution white-light video endoscopy in one system (tri-modal imaging). To diagnose gastric IM, selection of Helicobacter pylori positive patients is important because it increases pretest probability. For an endoscopic procedure, areas with H. pylori associated mucosal atrophy or IM are identified as areas that increase visibility of mucosal vessels and lose gastric folds in the white-light image; greenish mucosa in the gastric corpus in AFI imagery; and whitish patchy areas in NBI imagery. When the magnifying NBI is applied in the areas, IM can be diagnosed as mucosa with ridged, papillary or villiform surface structure in the corpus or mucosa, with whitish papillary or villiform surface structure in the antrum, with the light blue crest sign (white-bluish lines of light on the epithelial crests). This article is part of an expert video encyclopedia.

Diagnosis of Early Neoplasia in Barrett’s Mucosa Based on Changes in Surface Structure. Comparative Stereo-Microscopic and Histological Investigations in 600 Endoscopically Resected Specimens.

In view of the rapidly increasing incidence of Barrett's carcinoma, a desirable aim would be to detect intraepithelial neoplasia and mucosal carcinoma via the endoscope. Where something new is growing, it should give rise to visible changes in surface structure, in particular, in the case of the early Barrett's neoplasia. The present study was carried out to investigate this hypothesis. A total of 600 formalin-fixed endoscopically resected specimens (317 patients) from Barrett's oesophagus were prospectively investigated by stereomicroscopy (magnification up to x 90). The surface structure was classified into regular (finely granulated or ridged gyriform) and irregular (coarsely granulated, polypoid elevated or depressed), and compared with the results of the histological evaluation. 88.5 % of the Barrett's carcinomas, and 76 % and 68 %, respectively, of the cases of high-grade and low-grade intraepithelial neoplasia were associated with an irregular surface structure. However, coarsely granulated mucosal surfaces, reflecting regenerative changes, were also found in 26 % of the cases of Barrett's mucosa without intraepithelial neoplasia. Despite formalin fixation, 68 - 88.5 % of the cases of early Barrett's neoplasia can be identified by stereo microscopy. This shows that high-resolution videoendoscopy or magnification endoscopy appears to be a highly suitable method for the targeted detection of early Barrett's neoplasia.

S1670 A Potential Role for Intestinal Alkaline Phosphatase in Colonic Inflammation

Background: Colorectal cancer (CRC) is common and its incidence increases over time with the chronic intestinal inflammation observed in patients with Inflammatory Bowel Disease. Secreted Protein, Acidic and Rich in Cysteine (SPARC) has been show to affect tumour growth, cancer invasion and patient prognosis in numerous human cancers including bowel cancer. SPARC may also affect the colonic inflammatory response. Aim: To investigate SPARC's role on the development of colonic inflammation in the mouse. Methods: SPARC wild-type (WT) and knockout (KO) mice were treated with 3% dextran sodium sulphate (DSS) for 7 days. Intestinal inflammation was assessed on day 6, using the modified murine endoscopic score of colitis severity (MEICS), by high-resolution miniature video endoscopy. Mice were sacrificed and the colons assess histologically. In separate experiments, colons were harvested and total lymphocytes were isolated from the spleen, intra-epithelium (IE) and rest of colon (C) and were analysed for levels of CD4 and FoxP3 +ve cells by flow cytometry. Results: SPARC KO mice demonstrated less endoscopic colonic inflammation than WT mice (MEICS 4 vs 7; p=0.013) and less weight loss (KO 0.48% weight gain vs WT 6.2% weight loss p=0.074). Overall lymphocyte numbers isolated from spleen, IE and C fromKOwasmarkedly less than that isolated fromWTmice (0.77x108/ml vs 1.28x108/ml; 0.82x106/ml vs 16.8x106/ml and 4.4x106/ml vs 8.8x106/ml respectively). The percentage of CD4 +ve cells from spleen, IE and C were between 10-15% from both KO and WT mice. The percentage of FoxP3 +ve cells from spleen, IE and C from both KO and WT mice were 0.05% vs 1.85%, 1.2% vs 2.3%, 1.22% vs 1.75% respectively. Conclusion: SPARC affects the endoscopic colonic inflammatory response. Total lymphocyte counts are lower in inflamed SPARC KO colons and spleen consistent with a lower level of chronic inflammation. The percentage of FoxP3 +ve cells from the spleen and IE were lower in KO mice suggesting an impact of regulation of the immune response. The mechanistic impact of SPARC requires further elucidation.

Numerical Analysis of Autofluorescence Intensity of Neoplastic and Non-Neoplastic Colorectal Lesions Using a Novel Videoendoscopy System

Background and Aim: Recently, a novel high-resolution video autofluorescence endoscopy (AFE) system was developed. This study aimed to numerically evaluate the color tones in AFE images, in order to determine whether this innovative AFE system has the potential to distinguish between neoplastic and non-neoplastic colorectal lesions. Patients and Methods: Patients with colorectal lesions more than 10 mm in diameter which underwent AFE and were treated endoscopically or surgically from September 2005 to October 2008 were included in this study. The red (R), green (G), and blue (B) values of recorded digital AFE images were analyzed with special color-analysis software to calculate two indexes - the autofluorescence index (G/R ratio) for each lesion, and the color contrast index (ΔE∗ab value) for each lesion and corresponding normal region. Based on the final pathological diagnosis, lesions were classified into four categories - submucosal invasive cancer, intramucosal cancer, tubular or villous adenoma, and hyperplastic lesion. Results: During the study period, a total of 168 lesions from 156 patients were examined by AFE. The lesions consisted of 119 neoplastic lesions, including 34 submucosal invasive cancers, 43 intramucosal cancers, and 42 adenomas, and 49 non-neoplastic lesions which were all hyperplastic lesions. The mean G/R ratio was significantly higher in non-neoplastic lesions (1.11 [95% CI, 1.07-1.15], n = 49) than neoplastic lesions (0.67 [95% CI, 0.65-0.70], n = 119; P < .001). The mean ΔE∗ab value was significantly lower in non-neoplastic lesions (8.82 [95% CI, 7.75-9.89], n = 49) than neoplastic lesions (34.15 [95% CI, 32.16-36.14], n = 119; P < .001). Also, the mean G/R ratio and ΔE∗ab value for adenoma (0.77 [95% CI, 0.73-0.82], and 22.95 [95% CI, 19.98-25.92] respectively) were significantly different to those of intramucosal cancer (0.64 [95% CI, 0.61-0.67], and 39.60 [95% CI, 37.69-41.52] respectively) and submucosal invasive cancer (0.60 [95% CI, 0.56-0.63], and 41.09 [95% CI, 39.17-43.00] respectively). Conclusions: The numerical color-tone analysis of digital AFE images obtained from the novel high-resolution videoendoscopy system revealed that autofluorescence intensity was significantly different between non-neoplastic and neoplastic lesions, and AFE color-tone may represent the histopathological characteristics of the lesion.

Acceptance of Endoscopic Treatment of Patients with Early Barrett's Neoplasia

Background: Endoscopic treatment of early neoplastic lesions arising in Barrett's esophagus has gained more and more acceptance in recent years, especially in specialized centers. However, so far there is no valid data about the general acceptance of endoscopic treatment. Objective: To investigate the general acceptance of endoscopic therapy among major gastroenterological departments Design: A direct email survey was sent to all German University Hospitals and large community hospitals. Results: 40 gastroenterological departments were contacted and 27 responded (67.5%). All respondents were utilizing high-resolution video-endoscopy in combination with an advanced imaging technique (e.g. chromoendoscopy, NBI, FICE) and 92.5% EUS for the work up of patients with neoplastic lesions in Barrett's esophagus. 82% of the respondents were performing endoscopic resection (ER) with or without thermal ablative methods (e.g. APC) as the primary endoscopic treatment method. Only 14% were using photodynamic therapy (PDT) in combination with ER. 89% and 96% of the respondents would recommend ER as the treatment of choice to a 50-year old and 80-year old patient with mucosal Barrett's cancer (BC), respectively. However, in case of multifocal mucosal BC in a long segment Barrett's esophagus 73% of the respondents would recommend surgical treatment to a 50-year old patient (11% in case of a 80-year old patient). In case of a cancer invading the upper third of the submucosal layer without lymphatic invasion, 63% would recommend endoscopic treatment. Conclusions: These data suggest that endoscopic treatment, especially ER, is widely accepted as the primary treatment of choice in patients with early Barrett's neoplasia in Europe.

Numerical analysis of the autofluorescence intensity of neoplastic and non-neoplastic colorectal lesions by using a novel videoendoscopy system

Autofluorescence endoscopy (AFE) may improve detection and diagnosis of colorectal lesions. Recently, AFE based on a high-resolution video endoscope was developed. A novel high-resolution video AFE system was used to quantify autofluorescence of colorectal lesions to determine the characteristics of non-neoplastic and neoplastic lesions. Retrospective observational study. Single-center referral hospital. Ninety-seven patients with 103 colorectal lesions (22 non-neoplastic and 81 neoplastic lesions) who underwent AFE and were treated by using endoscopy or by surgery. Recorded digital AFE images were analyzed to quantify autofluorescence. The following autofluorescence indexes were calculated: the green/red (G/R) ratio for each lesion, the color-contrast index between each lesion, and the corresponding normal region. The G:R ratio, color-contrast index, and histopathologic characteristics for each colorectal lesion. The mean G/R ratio was significantly higher in non-neoplastic lesions (1.17 [95% CI, 1.10-1.24], n = 22) than in neoplastic lesions (0.65 [95% CI, 0.63-0.68], n = 81) (P < .001). Mean color-contrast indexes were significantly lower in non-neoplastic lesions (7.99 [95% CI, 6.40-9.58], n = 22) than neoplastic lesions (35.06 [95% CI, 32.79-37.33], n = 81; P < .001). With a cutoff value of 1.01 for the G/R ratio and 13.94 for color-contrast index, AFE had a sensitivity and specificity of 98.8% and 86.4% respectively, for G/R ratio, and 98.8% and 90.9%, respectively, for color contrast index, in differentiating neoplastic from non-neoplastic colorectal lesions. Retrospective design. The quantification of digital AFE images obtained from the novel high-resolution videoendoscopy system revealed that autofluorescence was significantly different between non-neoplastic and neoplastic lesions, and color tone in AFE may represent the histopathologic characteristics of the lesion.

Endoscopic video-autofluorescence imaging followed by narrow band imaging for detecting early neoplasia in Barrett's esophagus

Video-autofluorescence imaging (AFI) and narrow band imaging (NBI) are new endoscopic techniques that may improve the detection of high-grade intraepithelial neoplasia (HGIN) in Barrett's esophagus (BE). AFI improves the detection of lesions but may give false-positive findings. NBI allows for detailed inspection of the mucosal and (micro)vascular patterns, which are related to HGIN. A proof-of-principle study to combine AFI and NBI to improve the detection of HGIN and to reduce false-positive findings. Cross-sectional study of consecutive eligible patients. Single-center. Twenty patients with BE with suspected or endoscopically treated HGIN were investigated with 2 prototype imaging systems: AFI (inspection with high-resolution videoendoscopy and autofluorescence imaging for detection of lesions) and NBI (for detailed inspection of mucosal and vascular patterns of identified lesions). Lesions were sampled for histopathologic evaluation. The positive predictive value of AFI alone and of AFI-NBI for detecting HGIN and the reduction of false-positive findings because of the use of NBI. All of the 28 lesions with HGIN were identified with AFI. Seventeen were identified with white light (61%). Forty-seven suspicious lesions were detected with AFI: 28 contained HGIN (60%) and 19 were false positive (40%). With NBI, 25 of the true-positive lesions had definitely suspicious patterns, and 3 had dubiously suspicious patterns. Of the 19 false positives, 14 were not suspicious on NBI. The false-positive rate, therefore, was reduced from 40% to 10%. Low-grade dysplasia was found in 4 of the remaining 5 false positives. All of the 14 patients with HGIN were identified by AFI-NBI (sensitivity 100%). Uncontrolled study in high-risk patients. This proof-of-principle study confirms that AFI can be used as a red-flag technique to detect suspicious lesions. With NBI, detailed inspection of the surface patterns can be performed. This combination may increase the accuracy of detecting HGIN in BE.

Nonpolypoid (Flat and Depressed) Colorectal Neoplasms

Nonpolypoid (Flat and Depressed) Colorectal Neoplasms

Multi-detector CT-colonography in inflammatory bowel disease: Prospective analysis of CT-findings to high-resolution video colonoscopy

Aim Prospective analysis of multi-detector CT-colonography (MDCTC) in patients with inflammatory bowel disease (IBD) compared to high-resolution video-endoscopy (HRVC). Materials and methods Twenty-one patients (mean age 49.6 years) with Crohn's disease or ulcerative colitis underwent MDCTC (Somatom Volume Zoom, Siemens, Erlangen; 1 mm collimation, Pitch 8, 100 mAs, 120 kVp). HRVC was performed within 2 h after MDCTC. MDCTC was analyzed by two blinded readers. MDCTC-findings including bowel wall alterations and extraintestinal changes were compared to results of HRVC. Results Over-all-sensitivity was 100% for endoluminal lesions with correct diagnosis of two cancers. Acute and chronic IBD were correctly identified by MDCTC in 63.6%, and 100%, respectively, with a specificity of 75%, and 100%. Sensitivity, specificity, positive and negative predictive values of MDCTC for diagnosis of acute and chronic disease were best for chronic disease. Sensitivity was worst for acute ulcerative colitis and specificity was worst for acute Crohn's disease. Haustral loss was seen only in ulcerative colitis. Pseudopolyps and fistulae were findings exclusive to Crohn's disease. Particularly extraintestinal findings as increased vascularization and local lymphadenopathy correlated well with endoscopic definition of acute disease. Because of the possibly more vulnerable colonic wall in acute inflammatory bowel disease, the air inflation for MDCTC should be performed most carefully to avoid any risk of colonic perforation. Conclusion MDCTC may help to distinguish between patients with acute and chronic IBD. Especially extraintestinal complications, tumorous as well as pseudo-tumorous lesions can be detected with high sensitivity and specificity.

High-Resolution Magnifying Video Endoscopy in Primary Intestinal Lymphangiectasia: a New Role for Endoscopy?

Figure 1 A 21-year-old woman, with a 14-month history of recurrent diarrhea, steatorrhea, hypoproteinemia and peripheral oedema, underwent upper gastrointestinal endoscopy. A Fuji EG-485ZH video endoscope was used, which is capable of providing high-resolution images (because of its 850 000-pixel chip) and up to 2 × magnification. In the second part of the duodenum the mucosal surface had an appearance resembling rice grains (a), and diffuse fluid, which was producing a smoke-like mist, was observed (b).

Macroscopic Classification of Early Barrett's Neoplasia in 416 Lesions: Prospective Data From the Wiesbaden Barrett's Cancer Register

Background: The macroscopic appearance of early gastric cancer according to the Japanese criteria is an important prognostic factor for local endoscopic therapy in these patients. Sofar, there is no standardised classification of neoplasia in Barrett's esophagus and no prospective data about distribution of the different macroscopic types are available. Patients & Methods: All patients refered to our hospital for endoscopic therapy of early Barrett's cancer underwent an extensive staging programme including upper high resolution video endoscopy with biopsies of all visible lesions and four-quadrant biopsies and endoscopic ultrasound (EUS) (12.5 or 20 MHz miniprobes). The macroscopic type according to the Japanese classification for early stomach cancer (polypoid tumor (type I), flat and slightly elevated (IIa), flat and level (IIb), flat depressed (IIc), and ulcerated (III)) was defined by an experienced endoscopist. The local tumor stage was confirmed by EUS or endoscopic resection. These data were documented prospectively in an electronic database. Results: 380 patients (323 male, 57 female; mean age 66.6±10.9 years) with Barrett's neoplasia (416 lesions: high grade dysplasia (HGD) (n=32), mucosal (n=343) or submucosal (n= 41)) were included and documented. The distribution of the macroscopic type was as follows: Type I n=54 (13%); IIa n=152 (36.5%); IIb n=117 (28%); IIc n=17 (4%); IIa+c n=69 (16.5%); III n=7 (2%). 89% of all type IIb lesions were HGD or well differentiated and only 2% had submucosal invasion. Conclusion: This is the first analysis of the macroscopic type of early Barrett's neoplasia in a large number of patients and demonstrates the distribution in these patients. Harder to detect flat lesions are by far the most frequent neoplasias in Barrett's esophagus (85%). Type IIb seems to be the most favourable macroscopic type regarding differentiation and local tumor stage.

Does Chromo Endoscopy in Association with High-Resolution Video Endoscopy Improve Colorectal Adenomas Diagnosis by Colonoscopy?

Introduction: First intent exam for colorectal (CR) adenomas diagnosis is the colonoscopy. Structure enhancement function (SEF) and chromoscopy by indigo carmine dye solution (IC) intend to increase the detection of mucosal irregularities. The aim of this multicenter, randomized, prospective study was to determine if using combination SEF and chromoscopy, it would be possible to diagnose more adenomas by colonoscopy in a group of high risk level patients. Patients and methods: All included patients had individual history of CR adenomas and\or a first -degree family history of CR cancer (except genetic disease).They were randomized to have during the same session: either two successive colonoscopies with first passage without SEF/IC (to look for abnormalities of colour which would have been able to be masked with the dye) and second passage with SEF/IC (SEF/IC group); or two successive colonoscopies without SEF/IC (control group). The histopathology of all lesions was obtain on endoscopic resection specimens or biopsy specimens. Analysis concerned number, histopathology and location of colorectal lesions. Results: 294 patients were included (mean age: 59 years). 33% had individual history only, 48% had family history only and 19% both. The rate of patients with an adenoma or more was 39% (58/147) in the SEF/IC group and 36% (53/147) in the control group (NS). The total number of adenomas found in the SEF/IC group was 111 and 86 in the control group (NS). The number of adenomas > or = 10mm was not different in the 2 groups (total =11). This study identified 13 advanced CR lesions: 11 in the SEF/IC group (2 adenocarcinomas seen during the first passage and 9 high-grade dysplasia lesions (HGD), 7 seen during the first passage) and 2 in the control group (2 HGD). 60 patients (41%) had one or more hyperplastic polyp in the SEF/IC group and 39 (27%) in the control group (p=0,01). Conclusion: There is a trend to a better detection of adenomas by combining contrast chromoscopy and magnification colonoscopy, in a high risk level population but difference is not significant. On the basis of the presented data, we can not recommend the systematic use of these techniques for detection of adenomas in high risk level patients.

Laparoscopic Right Adrenalectomy: Report of Two Cases

Biochemical testing and imaging studies afford the surgeon many options in the evaluation of a patient with an adrenal mass. The development of a high resolution videoendoscopy system has made adrenal surgery one of the most applicable procedures for the laparoscopic approach. We report two cases of laparoscopic adrenalectomy through the lateral transabdominal approach. Case 1 is a 16-year-old male with pheochromocytoma of the fight adrenal gland; case 2 is a 35-year-old male with myelolipoma of the right adrenal gland- Both conditions were diagnosed by pathology. Both patients recovered uneventfully and were discharged 5 days postoperatively. We present the results of our laparoscopic right adrenalectomy and a review of the literature.

Endoscopic mucosal resection of premalignant lesions of the upper gastrointestinal tract

Surgical therapy of early malignancies of the upper gastrointestinal tract is associated with substantial morbidity and mortality, especially in elderly and co-morbid patients. In Japan endoscopic mucosal resection (EMR) has been proven to be safe and efficacious in this indication. 22 patients (68 +/- 14 years, 9 females) with high-grade dysplasia of the esophagus (n = 5), early carcinoma of the esophagus (T1N0M0, n = 11) or early gastric cancer (T1N0M0, n = 6) proven by high-resolution videoendoscopy (plus chromoendoscopy in most cases), miniprobe-endosonography (12-20 MHz) and biopsy were enrolled. The lesion size ranged from 7-40 mm in diameter. EMR was performed using a monofile snare, in almost all cases after submucosal injection of an attenuated epinephrine-solution (1:20,000) to effect a lifting sign. "En bloc" resection was possible in 17/22 cases (77 %), but in 5 patients piecemeal-resection had to be performed due to a larger lesion size. Active bleeding occurred on 14 of 22 occasions (64 %), in another 5 patients secondary bleeding (within 24 h after EMR) were detected. All these events could be managed endoscopically (mainly by hemoclip application) and blood transfusion was not required. Other complications did not occur. A complete resection (R0) was achieved in 21/22 cases, however, one patient had to undergo a second EMR procedure because histology of the first resected specimen had revealed malignant infiltration of the resection margin (R1). After the second EMR procedure complete (R0)-resection was obtained. Compared to the histological findings after EMR the pre-procedural staging proved to be correct in all cases. The control examinations (clinical exam, lab data, endoscopy with multiple biopsies, endosonography and CT) after EMR revealed no local or systemic cancer recurrence in 21/22 patients (median follow-up 5 months, range 3-12 months). However, in one patient with adenocarcinoma and Barrett-esophagus another mucosal adenocarcinoma was detected 3 months after EMR (located in opposite to the initial carcinoma treated with EMR). EMR seems to be a safe and effective (regarding local tumor control) therapy for high-grade dyplasia and early malignancies in the upper gastrointestinal tract. However, long-term follow-up in these patients has to be awaited.

High saturation red selectivity and high resolution video endoscopy for acute gi bleeding

High saturation red selectivity and high resolution video endoscopy for acute gi bleeding

Small, flat colorectal neoplasias in long-standing ulcerative colitis detected by high-resolution electronic video endoscopy

Background: High-resolution video endoscopy complemented with chromoscopy allows for more detailed visualization of the colonic mucosal surface. Methods: Using high-resolution video endoscopy and chromoscopy, we investigated 85 patients with extensive ulcerative colitis with a disease duration of at least 10 years who were taking part in a cancer surveillance program. Results: In 38 of the 85 patients, 104 polyps were detected at endoscopy. Seventy-seven (74%) of the 104 polyps were endoscopically flat, 21 (20%) were sessile, 3 (3%) were pedunculated, and 3 (3%) had no recorded morphology. Twenty-three (22%) polyps were neoplastic (15 flat, 5 sessile, 2 pedunculated, 1 not recorded). Low-grade dysplasia was found in 21 of the 23 neoplastic polyps and high-grade dysplasia in the remaining 2 (1 flat tubular adenoma and 1 sessile villous adenoma with invasive growth). Flat polyps were small, with a diameter of 5 mm or less in 73% (n = 56) of cases. At histology flat polyps revealed either flat adenomas (n = 11; 14.3%), tubular or villous structures with dysplastic cells at the lower part of the crypts (n = 4; 5.2%), flat hyperplastic polyps (n = 26; 34%), inflammatory mucosa (n = 5; 6.5%), or mucosa in remission (n = 31; 40%). Conclusion: The use of high-resolution video endoscopy complemented with chromoscopy in ulcerative colitis enables the detection of flat neoplastic polyps. The existence of those hitherto undetected neoplasms in ulcerative colitis and their possible role in the histogenesis of colorectal cancer in ulcerative colitis deserve further investigation. (Gastrointest Endosc 1996;44:15-22.)

Flat neoplastic lesions of the colon and rectum detected by high-resolution video endoscopy and chromoscopy

Because small flat colorectal neoplastic lesions (i.e., flat adenomas and flat adenocarcinomas) may be as translucent as the surrounding mucosa, they can remain undetected at conventional endoscopy. By combining high-resolution video endoscopy and chromoscopy, we detected 109 colorectal flat neoplastic lesions in 55 of 232 patients studied. Forty-three (78%) of the 55 patients with flat neoplastic lesions were over 60 years of age. No flat neoplastic lesions were seen in patients under 40 years of age. Flat neoplastic lesions were more frequent in men (35%) than in women (15%). Seventy-seven (71%) of the 109 flat neoplastic lesions measured 0.5 cm or less, 23 (21%) between 0.6 and 1.0 cm, and 9 (8%) more than 1.0 cm. Low-grade dysplasia and high-grade dysplasia were found in 94 (86%) and 13 (12%) of the flat neoplastic lesions, respectively. Adenocarcinoma was diagnosed in 3 (3%) flat lesions: 1 (1%) carcinoma originating in a flat adenoma and 2 (2%) adenocarcinomas without recognizable adenomatous elements. No adenocarcinomas were seen in lesions measuring 1.0 cm or less. Fourteen flat neoplastic lesions had a central depression at endoscopy. Flat neoplastic lesions with central depression more frequently showed high-grade dysplasia (43%) than did flat neoplastic lesions without central depression (7%). Central depression in flat neoplastic lesions should be considered a possible endoscopic marker for severe dysplasia. Our results suggest that flat neoplastic lesions occur more frequently than previously reported in Scandinavia. Flat adenomas may play an important role in the histogenesis of colorectal cancer (Gastrointest Endosc 1995;42:114-22.)

Percutaneous endoscopic implantation of Automatic Implantable Cardioverter/Defibrillator (AICD): an animal study of a new nonthoracotomy technique.

The Automatic Implantable Cardioverter/Defibrillator (AICD) prevents death due to malignant ventricular arrhythmias but requires thoracotomy for the implantation of the preferred two-patch lead system. The purpose of this study was to develop and test a new percutaneous endoscopic method of the AICD lead implantation without the need for open chest surgery. A high resolution video endoscopy system and currently available endoscopic instrumentation were used to develop pleural-pericardial dissection technique in 7 pigs and to endoscopically implant custom-made AICD patches in 20 pigs. An examining 10 mm rigid endoscope inserted in the 6th intercostal space in the anterior axillary line provided direct visual control for endoscopic dissection of the parietal pleura from the pericardium, delivery, and implantation of the AICD patches. This was successfully carried out through two trocars (10 and 11 mm) inserted into the pleural-pericardial space via the subxyphoid approach in 18 of 20 pigs. Effective patch positioning was confirmed by attaining a defibrillation threshold of 20J or less in 13 pigs. Of those, three required lead polarity reversal, and three others required lead repositioning to lower defibrillation thresholds to 20J or less. In three pigs, defibrillation thresholds of 30J or higher were required. Defibrillation was unsuccessful in two pigs due to patch malfunction. The authors conclude that percutaneous endoscopy is a feasible method of AICD lead implantation.

Laparoscopic Cholecystectomy: Instrumentation and Technique

Laparoscopic cholecystectomy is rapidly evolving as a therapeutic modality for the treatment of gallstone disease. The technical details of this procedure and the method by which the gallbladder is dissected and removed are critical to the safe, effective execution of the procedure. Our technique has been developed through extensive practice in porcine models and through experience with more than 250 patients. To perform laparoscopic cholecystectomy we employ a high-resolution video endoscopy system, two high-resolution color monitors, a high-flow CO2 insufflator, a 300 W Xenon light source, electrocautery and/or lasers, and an endoscopic suction-irrigation system. This equipment permits the surgeon to obtain a clear field of view within the abdomen. With these tools, appropriately designed for laparoscopic surgery, including a laparoscope, graspers, dissectors, cholangiography equipment, scissors, and clip appliers, the surgeon can remove the gallbladder without opening the abdomen. The procedure requires the induction of a CO2 pneumoperitoneum, insertion of four trocars, and placement of a grasping retractor to set the operative field. An additional retractor placed on Hartmann's pouch provides countertraction for dissection of the hilum. Careful dissection around the cystic duct and cystic artery with a combination of electrocautery and blunt dissection allows the surgeon to skeletonize the cystic duct and artery. After intraoperative cholangiography confirms the anatomy, the cystic artery and cystic duct are clipped and divided. Electrocautery or laser techniques can be used to perform retrograde dissection of the gallbladder from the liver bed and insure hemostasis. The gallbladder is detached and removed intact through the large trocars. This basic technique can be applied in a wide variety of patients with cholelithiasis. The surgeon proficient in this technique may apply it to a broad range of patients with gallbladder disease.