Endoscopic submucosal dissection with a novel high viscosity injection solution (LiftUp) in an ex vivo model: a prospective randomized study.

Introduction Endoscopic submucosal dissection (ESD) is increasingly being used in the western world. Submucosal injectates are an essential tool for the ESD procedure. In this study, we evaluated a novel copolymer injectate (LiftUp, Ovesco, Tübingen Germany) in an established ESD model (EASIE-R) in comparison to existing submucosal injectables. Materials and methods We conducted a prospective, randomized ex vivo study performing ESD with three injectates: LiftUp, hydroxyethyl starch (HAES 6 %) and normal saline solution (NaCl 0.9 %). A total of 60 artificial lesions, each 3 × 3 cm in size, were resected in an ex vivo porcine model, utilizing one of the three studied injectates (n = 20 ESDs per injectate). Study parameters were: en bloc resection rate, perforation rate, lifting property, time of injection, injectate volume, general ESD procedure time, and overall procedure time. Results All 60 lesions were successfully resected using the standard ESD technique. LiftUp had no procedure related perforations, one perforation occurred in the HAES group, and two perforations in the NaCl group ( P  > 0.05). Furthermore, adequate lifting was achieved in 16/20 (80 %) using LiftUp, 6/20 (30 %) in the HAES group and 6/20 (30 %) in the NaCl group ( P  < 0.0002). En bloc resection was achieved in 19 (95 %) with LiftUp, in 20 (100 %) with HAES, and in 16 (80 %) with NaCl. General ESD procedure time and overall procedure time were not different among the three groups. Conclusion LiftUp appears to be a safe alternative to established fluids for ESD. It had a significantly improved lifting effect and required significantly less injected volume compared to well-established lifting solutions.

[Foreign bodies in the upper gastrointestinal tract]. / Fremdkörper im oberen Gastrointestinaltrakt.

Foreign bodies in the upper GI tract are an important medical problem and cause about 5% of emergency endoscopies. Endoscopic removal is the method of the choice and is successful in 99% of cases. Nevertheless, endoscopic removal is not necessary in every case because most foreign bodies can pass through the digestive tract and be evacuated in the natural way. An immediate emergency endoscopy is indicated for foreign bodies in the esophagus with signs of obstruction, which is present in more than 75% of cases, because the risk of complications increases with retention time. The endoscopist has myriad possibilities for finding the best and safest way to extract the foreign body.

Modern enteroscopic interventions and characterization of nonmalignant postsurgical biliary anastomosis by double-balloon endoscopy.

BACKGROUND: Endoscopic access to strictured biliodigestive anastomoses often is difficult and may require percutaneous transhepatic biliary drainage or reoperation. METHODS: Push- or push-and-pull enteroscopy was used to diagnose disease and treat 24 postsurgical patients with suspected strictured biliodigestive anastomosis. Endoscopic retrograde cholangiography and biliary interventional procedures were used. Endoscopic accessibility, diagnosis of disease, therapeutic success, and complication rates were investigated at a single tertiary university gastroenterology center. RESULTS: Push enteroscopy reached biliary enteroanastomoses in 5 of the 24 patients (20.8%), whereas push-and-pull enteroscopy found choledocho- or hepaticojejunostomies in 17 of the remaining 19 postsurgical patients (89.4%). In all, successful enteroscopic intervention was achieved for 21 of the 24 patients (87.5%), whereas only 3 patients had to undergo percutaneous cholangiodrainage (12.5%). Cicatricially changed biliodigestive anastomoses were found in 14 of 21 patients (66.6%) including a mucosal type stricture in 7 patients (50%), an intramural type stricture in 5 patients (35.7%), and a ductal type stricture in 2 patients (14.2%). The remaining seven patients (33.3%) were normal. Enteroscopic interventions at strictured biliodigestive anastomosis included ostium incision for 8 (57.1%) and endoprosthesis insertion for 13 (92.8%) of the 14 patients, with prompt resolution of cholestasis and cholangitis. The major complications for the 24 patients involving 68 double-balloon enteroscopy (DBE) examinations comprised 2 perforations (8.3% per patient), 1 mild peritonitis (4.1%), and 1 cholangitis (4.1%), whereas minor complications were experienced by up to 20.8% of the patients. CONCLUSIONS: Modern interventional enteroscopy yields a high rate of successful interventions for strictured biliodigestive anastomosis, requires ostium incision for mucosal and intramural types of strictures, and helps to reduce percutaneous approaches.

Medical and endoscopic treatment in peptic ulcer bleeding: a national German survey.

OBJECTIVE: Peptic ulcers are the leading cause of upper gastrointestinal (GI) bleeding. The aim of this study was the evaluation of the recent clinical practice in drug therapy and endoscopic treatment of ulcer bleedings in Germany and to compare the results with the medical standard. METHODS: A structured questionnaire (cross-sectional study) was sent to 1371 German hospitals that provide an emergency service for upper GI bleeding. The project was designed similar to a nationwide inquiry in France in 2001. Forty-four questions concerning the following topics were asked: hospital organisation, organisation of emergency endoscopy service, endoscopic and drug therapy of ulcer bleeding, endoscopic treatment of variceal bleeding. Return of the questionnaires was closed in August 2004. RESULTS: Response rate was 675 / 1371 (49 %). Mean hospitals size was < 200 beds, 49 % (n = 325) had basic care level. 92 % provided a 24-hour endoscopy service, specialized nurses were available in 75 %. Fiberscopes were used only in 15 %. A mean of 10 +/- 12 (range: 0 - 160) bleeding cases/month were treated, 6 +/- 6 cases per month (60 %) were ulcer bleedings. Endoscopy was performed in 72 % immediately after stabilization but in all cases within 24 hours. The Forrest classification was used in 99 % whereas prognostic scores were applied only in 3 %. Forrest Ia,/Ib/IIa/IIb/IIc/III ulcers were indications for endoscopic therapy in 99 %/ 99 %/ 90 %/ 58 %/ 4 %/ 2 % respectively. Favoured initial treatment was injection (diluted epinephrine, mean volume 17 +/- 13 mL/lesion) followed by clipping. In re-bleedings, 93 % tried endoscopic treatment again. Scheduled re-endoscopy was performed in 63 %. PPI were used in 99.6 %, 85 % administered standard dose twice daily. PPI administration was changed from intravenous to oral with the end of fasting in nearly all hospitals. PPI administration schemes can be improved. Indications for Helicobacter pylori eradication followed rational principles. CONCLUSION: Medical and endoscopic treatment of bleeding ulcers reached a high standard, although some therapeutic strategies leave room for improvement. Bigger hospitals tend to be closer to the medical standard.

Clinical significance of lymphoid hyperplasia of the lower gastrointestinal tract.

Lymphoid hyperplasia of the intestine has been associated with multiple diseases and symptoms. This study was undertaken to analyze the number and topographical distribution of the lymphoid follicles. A total of 302 adult consecutive patients were enrolled when they underwent elective colonoscopy. Standardized pictures from terminal ileum and colon were taken using video colonoscopes. In each picture, the number, size, and mucosal elevation of lymphoid follicles were analyzed in relation to histological and immunological findings and medical history. Lymphoid hyperplasia was found to be most extensive in the terminal ileum and cecum. Patients with untreated gastrointestinally mediated allergy (GMA) showed the highest number of lymphoid follicles per visible field in the terminal ileum ( P < 0.001) and cecum ( P = 0.003) vs. the control group. Patients with infectious colitis also showed a high number of lymphoid follicles per endoscopic visible field in the transverse colon ( P = 0.020). The presence of lymphoid hyperplasia is a frequent finding during colonoscopy. It may indicate an enhanced immunological mucosal response to antigenic stimulation such as GMA or infection.

Percutaneous endoscopic jejunostomy and jejunal extension tube through percutaneous endoscopic gastrostomy: a retrospective analysis of success, complications and outcome.

BACKGROUND: Percutaneous access to the jejunum is an important approach if gastrostomy feeding is not possible. OBJECTIVE: To analyze success, short- and long-term complications (STCs, LTCs) in patients with percutaneous endoscopic jejunostomy (PEJ) and jejunal access through percutaneous endoscopic gastrostomy (Jet-PEG). METHODS: A retrospective analysis of endoscopically placed PEJs and Jet-PEGs. Success rates, mortality, STCs and LTCs were investigated for risk factors comprising demographic data, underlying disease, previous surgery and experience of the endoscopist. RESULTS: 205 PEJ and 58 Jet-PEG placements were included in the study. PEJs and Jet-PEGs were successfully placed in 65.4 and 89.7%, respectively. Billroth II surgery predisposed in favor of a significantly higher success rate for PEJ placement (p = 0.014, OR = 2.27). Inexperienced examiners have a significantly (p = 0.040) lower success rate for tube insertion than examiners with a medium level of experience. STCs and LTCs occurred evenly in PEJ and Jet-PEG patients. Dislocation of the tube occurred significantly more frequently in Jet-PEG patients (33.3%, p = 0.005). Aspiration was most common for bedridden patients. CONCLUSION: PEJ has a significantly lower success rate for insertions, but fewer LTCs. The experience of the endoscopist correlates with the success rate of tube insertion.

Local infection after placement of percutaneous endoscopic gastrostomy tubes: a prospective study evaluating risk factors.

BACKGROUND: Due to its high efficacy and technical simplicity, percutaneous endoscopic gastrostomy (PEG) has gained wide-spread use. Local infection, occurring in approximately 2% to 39% of procedures, is the most common complication in the short term. Risk factors for local infection are largely unknown and therefore--apart from calculated antibiotic prophylaxis--preventive strategies have yet to be determined. OBJECTIVE: To assess the potential patient- and procedure-related risk factors for peristomal infection following PEG tube placement. METHODS: Potential patient-related (eg, age, sex, diseases, body mass index, concomitant antibiotic therapy) and procedure-related (endoscopist experience, institutional factors, findings on endoscopy) risk factors and their coincidence with local infection, defined as a positive peristomal infection three days after PEG tube placement, were evaluated at two institutions. A standardized antibiotic prophylaxis was not performed. The peristomal infection score was also evaluated in 390 patients. RESULTS: Using a multivariate binary regression analysis, four risk factors were established as relevant for local infection after PEG: clinical institution (OR 6.69; P = 0.0001), size of PEG tubes (15 Fr versus 9 Fr; OR 2.12; P = 0.05), experience of the endoscopist (more than 100 investigations versus less than 100 investigations; OR 0.54; P = 0.05) and the existence of a malignant underlying disease (OR 2.28; P = 0.019). CONCLUSIONS: Similar to other endoscopic interventions, local infection as a complication of PEG tube placement depends on the experience of the endoscopist. Institutional factors also play a significant role. Additional risk factors include PEG tube size and underlying diseases. These findings indicate that the local infection after PEG tube placement may be influenced by both endoscopy-associated factors and by the underlying disease status of the patient.

A novel model for training in ERCP with double-balloon enteroscopy after abdominal surgery.

BACKGROUND: Since the first presentation of the compactEASIE in 1997, this training model has become established for nearly all interventional techniques in upper gastrointestinal endoscopy including ERCP. So far, training using double-balloon enteroscopy (DBE) for ERCP has not become established. AIMS: This paper presents a special organ preparation for the compactEASIE model which for the first time allows simulation of ERCP in patients who have had prior abdominal surgery. Two abdominal organ packages from freshly slaughtered pigs were used to create a postsurgical anatomic situation. RESULTS: A life-like training model was established for ERCP training in a postsurgical anatomic situation. A Roux-en-Y anastomosis was created such that the papilla was located around 100 cm beyond the pylorus. The duodenum was closed shortly above the pig papilla at the level of the pylorus. The papilla was successfully reached by DBE after 40 minutes. The papilla was cannulated and regular contrasting of the biliary system using fluoroscopy was achieved. Sphincterotomy, stent placement and exchange, and needle-knife sphincterotomy over a 7-Fr stent were conducted successfully. CONCLUSION: Modified organ preparations allow the simulation of and training in ERCP in postsurgical anatomic situations in training models using animal parts.

The compactEASIE is a feasible training model for endoscopic novices: a prospective randomised trial.

BACKGROUND: The objective benefit of a training using the compact Erlangen Active Simulator for Interventional Endoscopy-simulator was demonstrated in two prospective educational trials (New York, France). The present study analysed whether endoscopic novices are able to reach a comparable level of endoscopic skills as in the above-described projects. METHODS: Twenty-seven endoscopic novices (medical students, first year residents) were enrolled in this prospective, randomised trial. The compact Erlangen Active Simulator for Interventional Endoscopy-simulator with an upper GI-organ package and blood perfusion system was used as a training tool. Basic evaluation of endoscopic skills was performed after a practical and theoretical course in diagnostic upper GI endoscopy followed by a stratified randomisation according to the rating in endoscopic skills into intensive (n=14) and control group (n=13). The intensive group was trained 12 times every second week over 7 months in 4 endoscopic disciplines (manual skills, injection therapy, haemoclip, band ligation) by skilled endoscopist (three trainees/simulator). Assessment was performed (single steps/overall) using an analogue scale from 1 to 10 (1=worst, 10=optimal performance) by expert tutors. The control group was not trained. Blinded final evaluation of all participants was performed in January 2003. RESULTS: We observed in all techniques applied a significant improvement of endoscopic skills and of the performance time in the intensive group compared to the control group (p<0.001). The comparison with the previous projects showed that the intensively trained novices achieved comparable levels of performance to the GI fellows in the New York and France Project (at least 80% of the median score in three out of four techniques). CONCLUSION: Endoscopic novices acquired notable skills in interventional endoscopy in the simulator by an intensive, periodical training using the compactEASIE.

Hemodynamic efficacy of the new resolution clip device in comparison with high-volume injection therapy in spurting bleeding: a prospective experimental trial using the compactEASIE simulator.

BACKGROUND AND STUDY AIMS: Peptic ulcers are the most frequent cause of gastrointestinal bleeding. The use of hemoclips has become established as an effective form of treatment in addition to injection therapy. However, hemoclips have not previously been compared with injection therapy in an experimental setting using objective parameters. MATERIALS AND METHODS: In a prospective, randomized, and controlled trial, the disposable Resolution hemoclip device (Boston Scientific, n = 40) was compared with conventional injection therapy (n = 40) in an experimental setting, using the compactEASIE simulator equipped with an upper gastrointestinal organ package to simulate bleeding. Four investigators with different levels of endoscopic experience participated in the study. On a randomized basis, each investigator treated 20 bleeding sites either by applying one clip (n = 10) or by carrying out high-volume four-quadrant injection (4 x 10 ml saline) of a spurting vessel. The efficacy of the hemostasis was assessed by continuous measurement of pressure within the afferent vessel before and after clip application or injection therapy and calculating the relative reduction in the vessel's diameter with each treatment method. The system pressure was recorded 1 min before and 1 min after treatment. The ease of application of each method was rated by the endoscopist and by the assisting nurse using a visual analogue scale (0 - 100, with 100 being best). RESULTS: All of the 40 hemoclipping and injection treatments were carried out successfully. Both methods led to a significant increase in peak pressure (Resolution clip 71.8 +/- 66.8 mm Hg, P < 0.001; injection 71.9 +/- 53.8 mm Hg, P < 0.001), representing a significant relative reduction in the vessel diameter. There were no significant differences in peak pressure between the two treatments ( P = 0.995). The mean increase in pressure during the first minute after the intervention (clip 49.3 +/- 67.0 mm Hg vs. injection 19.9 +/- 41.6 mm Hg) was significantly greater with the hemoclipping procedure ( P = 0.021). More experienced investigators achieved a greater increase in system pressure, but the difference was not significant. The assessments of the ease of application by the assistants (84 +/- 13) and endoscopists (86 +/- 16) did not show any significant differences ( P = 0.402) for the clipping device. CONCLUSIONS: No significant differences between the two treatment methods were detected with regard to the immediate efficacy of hemostasis. However, long-term hemostasis was better with hemoclipping. The endoscopist's level of experience also appears to play a role, particularly when hemoclips are used.

"Hemodynamic efficacy" of two endoscopic clip devices used in the treatment of bleeding vessels, tested in an experimental setting using the compact Erlangen Active Simulator for Interventional Endoscopy (compactEASIE) training model.

BACKGROUND AND STUDY AIMS: Hemoclip therapy is a well-established procedure in the treatment of gastrointestinal bleeding. Although new products are provided periodically by the industry, comparative investigations are lacking. We compared two different hemoclip devices in an experimental setting, assessing them using objective hemostatic parameters. MATERIALS AND METHODS: We compared two disposable clip devices (Olympus HX-200L-135 (n = 40) vs. Wilson-Cook Tri-Clip (n = 40)) in an experimental setting using the compact Erlangen Active Simulator for Interventional Endoscopy (compactEASIE) training model equipped with an upper gastrointestinal-organ package for bleeding simulation. This was a randomized, prospective, controlled trial. Four investigators with different levels of endoscopic experience applied ten hemoclip devices of each type to the spurting vessels, the clips allocated using a randomized list for each investigator. The efficacy of hemostasis was determined by continuous measurement of the pressure within the afferent vessel before and after clip application and calculation of the relative reduction of vessel diameter by the clip device. The system pressure was recorded over the period from 1 minute before to 1 minute after clip application. A secondary end point was a subjective assessment of the whole clip application procedure by the endoscopist and the assisting nurse, using a visual analog scale (0 - 100, with 100 representing the best experience). RESULTS: A total of 39/40 clips of each type were applied successfully. Both clip devices led to a significant increase in system pressure, representing significant relative reduction of vessel diameter (Olympus 5.4 +/- 7.5 %, p < 0.001; Cook 4.9 +/- 8.0 %, p < 0.001). Overall, there was no significant difference between the two devices ( P = 0.756). However, the investigator with the least experience in endoscopy (< 100 procedures) produced significantly inferior results compared with the other three investigators, who had performed between 2000 and 6000 procedures each ( P < 0.05). We found no evidence of a learning curve from the intra-observer results. The devices received good, but not significantly different, overall ratings by the endoscopists (Olympus 69 +/- 24 vs. Wilson-Cook 65 +/- 16) and by the assisting nurses (Olympus 77 +/- 9 vs. Wilson-Cook 70 +/- 22). CONCLUSIONS: Using an established cadaveric training model, no significant difference was found between the two types of hemoclip devices with respect to their "hemostatic efficacy". However, the experience of the endoscopist appears to play a major role in successful clip application. The use of a feedback mechanism in emergency endoscopy training, using continuous intravessel pressure monitoring, may substantially enhance the efficacy of training, resulting in a similar improvement in clinical results.

Objective benefit of a 1-day training course in endoscopic hemostasis using the "compactEASIE" endoscopy simulator.

BACKGROUND AND STUDY AIMS: The Erlangen Active Simulator for Interventional Endoscopy (EASIE) was introduced in 1997 as a training model for interventional endoscopy. Objective evidence of the benefits of training with this model has not previously been published. As part of two long-term projects, the benefits of a 1-day training course with the "compactEASIE" simulator were evaluated. MATERIALS AND METHODS: Fourteen American and 18 French gastroenterology fellows were enrolled. These fellows were participants in the intensive groups performing training in endoscopic hemostasis, with a total number of 28 fellows in New York and 36 in France. Gastrointestinal endoscopy faculty members in New York and France evaluated and timed the fellows in four disciplines to establish baseline skills (manual skills; injection and coagulation; Hemoclip application; and variceal ligation) with the compactEASIE simulator. The trainees were reevaluated after an intensive 1-day course (with two or three fellows and one instructor per station), also including preparation and assistance for each procedure. The assessment (overall and parts) was done by expert tutors using an ordinal scale ranging from 1 to 10 (1 = poorest, 10 = best), recording also mistakes and performance time. The compactEASIE simulator, equipped with an upper gastrointestinal organ package and an artificial blood perfusion system, was used as the training tool. RESULTS: A highly significant improvement ( P < or = 0.001) was observed in the performance of all endoscopic techniques. A significant reduction in performance time was also observed with three of the four endoscopic techniques. Successful hemostasis was significantly improved in two out of three techniques. CONCLUSIONS: A 1-day training course on endoscopic hemostasis using the compactEASIE simulator is capable of improving the performance of hemostasis procedures. Long-term effects of repeated training sessions are currently subject of collaborative studies in New York and France.

Successful laserlithotripsy in Bouveret's syndrome using a new frequency doubled doublepulse Nd:YAG laser (FREDDY).

Gastric outlet obstruction as a result of gallstone (Bouveret syndrome) is a rare but serious complication of cholelithiasis. In many cases, surgery has been conducted for treatment. In recent years, minimal invasive treatment modalities (e.g. shockwave lithotripsy) have been shown to be effective in some of those patients. Laserlithotripsy has so far been described in two cases with a Rhodamine-6G dye laser. We present the case of a 90-year-old woman with duodenal obstruction due to a huge gallstone. The patient was referred to our hospital because attempts at endoscopic extraction and extracorporeal shockwave lithotripsy had failed. The man was treated successfully in just one session with a new cost-efficient frequency doubled doublepulse Nd:YAG laser (FREDDY) using a total of 5726 laser pulses (120 mJ pulse energy, 10 Hz pulse repetition rate) and recovered rapidly. Laserlithotripsy can be considered an effective non-invasive therapeutic alternative to surgical treatment in Bouveret's syndrome, especially in old or high-risk patients.

The compact Erlangen Active Simulator for Interventional Endoscopy: a prospective comparison in structured team-training courses on "endoscopic hemostasis" for doctors and nurses to the "Endo-Trainer" model.

BACKGROUND: In 1997 Hochberger and Neumann presented the "Erlangen Biosimulation Model" (commercialized as the "Erlangen Endo-Trainer") at various national and international meetings. The new compactEASIE is a simplified version of the original "Biosimulation Model" (Endo-Trainer) and is specially designed for easy handling. CompactEASIE is reduced in its features, focusing exclusively on flexible endoscopy training. The acceptance of training in endoscopic hemostasis is accepted by workshop participants, as evaluated by a questionnaire on both models. METHODS: Eleven structured courses on endoscopic hemostasis for doctors and nurses organized by the same endoscopists from 3/1998 to 5/1999 were evaluated using one of both models. The questionnaires were filled in by 207/291 trainees (71%). The Endo-Trainer was used in 4 (n = 103) and the compactEASIE in 7 courses (n = 104). Both simulators were equipped with identical types of specially prepared pig-organ packages consisting of esophagus, stomach and duodenum, including artificial sewn-in vessels, polyps and varices. Blood perfusion was done with a roller pump connected to the sewn-in vessels and blood surrogate. All workshops were identical concerning the course structure: a 30-min theoretical introduction on ulcer bleeding was followed by 2 h of practical training in injection techniques and hemoclip application. The second part of variceal therapy consisted of a 30-min theoretical introduction prior to 2 h of practical training on sclerotherapy, band ligation and cyanoacrylate application. Finally, a questionnaire on the trainees' pre-experience and their rating of the different workshop sections was handed out to each participant. RESULTS: Previous endoscopic experience was comparable in both groups. The training in both simulators was highly accepted by the trainees (compactEASIE 95% excellent and good versus EASIE (Endo-Trainer) 97%) and did not show any significant difference (P = 0.493). Even in the assessment of the single techniques, no statistical difference was observed. Furthermore, the assessments of the closeness to reality and the endoscopic environment in both simulators were identical. CONCLUSIONS: Both simulators (Endo-Trainer, compactEASIE) are excellent educational tools for interventional endoscopy with a high level of acceptance. The easy-to-handle, "lightweight" compactEASIE is a significant, progress tool for the future.

Endoscopic antireflux treatment: fact, fiction or future?

Medical therapy with proton pump inhibitors (PPIs), aside from surgery, is the established and most effective treatment approach for chronic gastroesophageal reflux disease (GERD). Recently developed endoscopic antireflux procedures may be an alternative for a subset of patients with uncomplicated, mild GERD. Given the perioperative morbidity and mortality risk of laparoscopic fundoplication, less invasive semi-surgical and flexible endoscopic techniques may be an option for patients who cannot or wish not to take long-term medication. These clinical procedures include endoscopic suturing devices, focal radiofrequency coagulation in the cardia and bioimplants. While many of these techniques have shown good results in preliminary studies, long-term results are not yet available and therefore all such procedures have to be considered experimental. Their effectiveness will need to be compared with that of established treatment forms.

Management of difficult common bile duct stones.

More than 80% of all CBD stones can be effectively treated by endoscopic sphincterotomy and stone extraction using baskets or balloon catheters. For stones up to 2.5 cm in diameter, mechanical lithotripsy is the method of choice as a next step. Very large, impacted, or very hard concretions, however, often make mechanical lithotripsy cumbersome or even impossible. For these stones laser lithotripsy, EHL, and ESWL are nonoperative options, especially for elderly patients and patients with an elevated surgical risk. Because these methods are often only available at endoscopic centers, stenting is a treatment modality for immediate stone therapy, but as a definitive treatment it should be restricted to selected cases. ESWL, EHL, and laser lithotripsy yield similar success rates of 80% to 95% and may be used complementarily in endoscopic centers. ESWL is the preferred therapy in intrahepatic lithiasis. Laser lithotripsy shows the best results in CBD stones. Electrohydraulic lithotripsy is rarely used because of its high potential for tissue damage and bleeding. Laser lithotripsy using smart laser systems such as the rhodamine 6G dye laser and the FREDDY laser system can simplify the treatment of these difficult bile duct stones. The rhodamine 6G-dye laser allows blind fragmentation of these stones by exclusive insertion of a 7-F metal marked standard catheter into the bile duct by standard duodenoscopes using intermittent fluoroscopy. An oSTDS safely cuts off the laser pulse if contact with the stone is lost, thus preserving the bile duct from potential damage. Unfortunately the system is no longer produced. The new FREDDY laser lithotriptor with a piezoacoustic stone/tissue discrimination system offers an alternative to the rhodamine 6G dye laser system at less than half the financial investment. Effective stone fragmentation is accompanied by only low tissue alteration. The holmium:YAG laser is an effective multidisciplinary lithotriptor, but it can be used only under cholangioscopic control, limiting its use to gastroenterologic centers.

Tele-endoscopy: influence of data compression, bandwidth and simulated impairments on the usability of real-time digital video endoscopy transmissions for medical diagnoses.

BACKGROUND AND STUDY AIMS: Real-time digital video transmission (rtDVT) at an acceptable quality through networks has been possible for several years. This technique can be used for telemedical applications, such as tele-endoscopy. The hypotheses of the present study were that the quality of real-time DVT depends on the technical equipment used, and that the resulting image quality influences the usability of the system for diagnostic purposes. MATERIALS AND METHODS: An experimental network was established between two German referral endoscopy centers, using the Asynchronous Transfer Mode (ATM) protocol. At first, rtDVTs of routine gastrointestinal video endoscopies were transferred through the network for prospective evaluation of the feasibility of the technical equipment and its usability for diagnostic tele-endoscopy, based on the video image quality. Secondly, the image quality and usability for correct telemedical diagnosis were evaluated prospectively in a double-blind experimental setting in relation to variations in the methods of data compression used, transmission bandwidths, and simulated transmission errors. Fourteen endoscopists evaluated 27 variations of an endoscopic video sequence. RESULTS: Compression with the Moving Picture Expert Group 2 (MPEG2 [4 : 2 : 2]) standard, the ATM protocol, and a bandwidth of 40 megabits per second (Mb/s) were used successfully in 40 routine tele-endoscopies for practical evaluation. Doctors were able to handle the system with ease, and its availability was 100%. There were no detectable differences between the original video image and the transferred image, and the images were usable for diagnosis in all cases. The set-up used clinically was therefore considered to provide the optimal conditions for comparisons in the experimental part of the study. Experimentally, any technical variation was found to cause a reduction in the overall image quality and hence a reduction in diagnostic usability: compression algorithm (MPEG2 [4 : 2 : 2] vs. others: P = 0.001), bandwidth (> or = 8 vs. < 8 Mb/s: P = 0.001), and error rate (10 (-8) vs. 10 (-7): P = 0.001). CONCLUSIONS: rtDVT using MPEG2 [4 : 2 : 2] compression and a bandwidth of 40 Mb/s did not effectively differ from the original video images in routine tele-endoscopy. The qualitative requirements in diagnostic video endoscopy, however, are obviously much higher than previously assumed, since experienced endoscopists detected a loss of image quality and a reduction in diagnostic usability with any reduction in the technical specification. Modern methods of data compression, broadband networks and a network protocol with good quality-of-service guarantees are therefore prerequisites for diagnostic rtDVT.