Biomedical subjects

Ralf Jakobs

Publications and source records attributed to Ralf Jakobs.

13 recordsLinked to original sources

PubMed2006

Computer-assisted colonoscopy (the NeoGuide Endoscopy System): results of the first human clinical trial ("PACE study").

OBJECTIVES: Unsedated colonoscopy is an uncomfortable procedure for most patients. Discomfort during colonoscopy is largely related to looping of the colonoscope, which displaces the colon from its native configuration and stretches attachments to the mesentery. A novel computer-assisted colonoscope utilizes a fully articulated, computer-controlled insertion tube. On manual insertion of the colonoscope, the position and angle of the scope's tip are encoded into a computer algorithm. As the colonoscope is advanced, the computer directs each successive segment to take the same shape that the tip had at a given insertion depth. The insertion tube thus changes its shape at different insertion depths in a "follow-the-leader" manner. METHODS: This initial clinical trial with this novel colonoscopy system was designed as a prospective, nonrandomized, unblinded, feasibility study. Three physicians of varying levels of experience participated in the study. RESULTS: Eleven consecutive patients (seven men, four women, age range 19-80) meeting inclusion criteria for screening or diagnostic colonoscopy were enrolled in the study. The cecum was reached in 10 consecutive patients (100%). Findings included diverticular disease in two cases and multiple colonic polyps in two cases. Postprocedure assessment at discharge, 48 h, and 30 days revealed no complications or adverse effects. Physician satisfaction and patient acceptance of this new technique were high. CONCLUSIONS: In this limited, first of its kind feasibility study, the computer-assisted colonoscope was shown to perform colonoscopy safely and effectively. The colonoscope's unique design limited loop formation during colonoscopy. Large-scale clinical trials are indicated.

Adult↗

PubMed2006

Diagnosis of obscure gastrointestinal bleeding by intra-operative enteroscopy in 81 consecutive patients.

AIM: To analyze the results and complications of intra-operative enteroscopy (IOE) by investigating a series of selected patients with bleeding suspected to originate from the small intestine. METHODS: Eighty-one patients (mean age: 65 years) including 40 males (49.4%) and 41 females (50.6%) with obscure gastrointestinal bleeding underwent IOE between 1990 and 2004. The patients were identified from a database and data were selected from the patients' charts retrospectively. All the patients had undergone at least one non-diagnostic esophagogastroduodenoscopy, colonoscopy, standard enteroscopy and a negative abdominal ultrasound scan before IOE. RESULTS: The median minimal hemoglobin level in the patients was 59 + 15 g/L and 72.8% of the patients required transfusion of packed erythrocytes previously. A bleeding source was detected in 68 (84%) of the patients during IOE. Angiodysplasiae were found in 44 patients (54.3%) and 9 patients (11.1%) were affected by ulcers in the small intestine. A tumor in the small intestine was detected in another 6 patients. The treatment consisted of argon-plasma-coagulation, surgical suture or limited resection in most of the patients. CONCLUSION: Intra-operative enteroscopy is still used for the diagnosis of suspected small bowel bleeding. Recent developments such as wireless capsule endoscopy and double balloon enteroscopy, may lead to the replacement of IOE in the future.

Adult↗

PubMed2006

Accuracy of high-resolution chromoendoscopy in prediction of histologic findings in diminutive lesions of the rectosigmoid.

BACKGROUND: The ability to differentiate adenomatous from nonadenomatous colonic polyps by using chromoendoscopy would obviate the need to remove hyperplastic lesions. The aim of this study was to define the accuracy of high-resolution chromoendoscopy for the determination of colonic polyp histology. METHODS: In 158 patients, 273 polyps (<5 mm) in the rectosigmoid were estimated for their histology. The endoscopists, in two steps, predicted the histopathology of each lesion on the basis of its surface characteristics by using high-resolution colonoscope without any staining and after indigo carmine dye according to the Kudo classification. RESULTS: The resected polyps included 48 adenomatous and 225 nonadenomatous polyps. When histologically confirmed hyperplastic polyps were compared with adenomatous polyps, the prediction of hyperplastic polyps based on endoscopic findings had a sensitivity of 93%, a specificity of 60%, and an overall accuracy of 81%. The corresponding sensitivity, specificity, and overall accuracy after indigo carmine dye were 94%, 64%, and 83%, respectively. CONCLUSIONS: The results suggest that the chromoendoscopy only marginally improves the determination between hyperplastic and adenomatous polyps when using high-resolution colonoscopes. The overall accuracy rate increased after dyeing, from 81% to 83%. The omission of histopathologic analysis cannot yet be achieved by chromoendoscopy.

Adenoma↗

PubMed2006

Risk factors for symptomatic stone recurrence after transpapillary laser lithotripsy for difficult bile duct stones using a laser with a stone recognition system.

BACKGROUND: Laser-induced shock-wave lithotripsy (LISL) is successfully used for the treatment of difficult bile duct stones. The aim of this study was to assess the long-term risk for a symptomatic bile duct stone recurrence after LISL and to detect risk factors predicting recurrence. METHODS: Between 1993 and 2001, 80 patients with difficult bile duct stones were successfully treated by intracorporeal LISL through the papilla of Vater. Seventy-one of these patients [median age, 65.8 years; 51 women (71.8%)] were followed for a median (range) period of 58 (1-114) months. RESULTS: Eleven patients (15.5%) had a symptomatic stone recurrence. The median (range) period between laser lithotripsy and recurrence was 40 (5-85) months. The presence of a bile duct stenosis (P=0.032) and a body-mass index below 25 (P=0.025) were significantly associated with an increased risk for stone recurrence. A gallbladder in situ, the presence of gallbladder stones, dilation of the bile duct, or a peripapillary diverticulum was not associated with stone recurrence. CONCLUSIONS: The presence of a bile duct stenosis is significantly related to bile duct stone recurrence after treatment with LISL. The impact of the body mass index on stone recurrence is interesting. The gallbladder status did not predict stone recurrence in our study.

Aged↗

PubMed2005

Colorectal polyps: detection with dark-lumen MR colonography versus conventional colonoscopy.

PURPOSE: To prospectively compare dark-lumen magnetic resonance (MR) colonography with conventional colonoscopy in the detection of colorectal polyps. MATERIALS AND METHODS: Local ethical committee approval and informed consent were obtained. One hundred consecutive patients (56 men, 44 women; mean age +/- standard deviation, 67.7 years +/- 14.7; range, 25-82 years) who were referred for conventional colonoscopy from January 2003 to January 2004 underwent MR colonography and conventional colonoscopy after standard precolonoscopic bowel cleansing. Colonoscopy was performed immediately after MR colonography. For MR colonography, the colon was filled with approximately 2000 mL of tap water. Imaging was performed with a 1.5-T MR unit with patients in the prone position. A T1-weighted three-dimensional volumetric interpolated breath-hold sequence was performed before and 75 seconds after intravenous administration of 0.2 mmol gadobenate dimeglumine per kilogram of body weight. Results of MR colonography were analyzed on a per-polyp and per-patient basis. Findings at colonoscopy were used as the reference for determining accuracy, sensitivity, specificity, and positive and negative predictive values of MR colonography. RESULTS: Of 100 patients recruited for study, 92 (52 men, 40 women; mean age, 61.5 years +/- 14.5; range, 25-82 years) underwent complete MR and conventional colonoscopy examinations. Forty-three of the 92 patients (47%) had normal findings at conventional colonoscopy. In the other 49 patients (53%), conventional colonoscopy depicted 107 polyps (82 adenomas, 25 hyperplastic polyps) and seven carcinomas. At per-polyp analysis, sensitivity of MR colonography in the detection of adenomatous polyps was 100% for polyps at least 10 mm in diameter and 84.2% for polyps 6-9 mm in diameter. At per-patient analysis, the accuracy of MR colonography was 93.1% (sensitivity, 89%; specificity, 96%) if detection of adenomatous polyps of all sizes was considered. CONCLUSION: Dark-lumen MR colonography is a promising modality with high accuracy for detecting colorectal polyps larger than 5 mm in diameter.

Adult↗

PubMed2005

A prospective two-center study comparing wireless capsule endoscopy with intraoperative enteroscopy in patients with obscure GI bleeding.

BACKGROUND: Capsule endoscopy enables noninvasive diagnostic examination of the entire small intestine. However, sensitivity and specificity of capsule endoscopy have not been adequately defined. We, therefore, compared capsule endoscopy by using intraoperative enteroscopy as a criterion standard in patients with obscure GI bleeding. METHODS: Forty-seven consecutive patients with obscure GI bleeding (11 with ongoing overt bleeding, 24 with previous overt bleeding, and 12 with obscure-occult bleeding) from two German gastroenterologic centers were included. All patients who had a prior nondiagnostic evaluation, including upper endoscopy, colonoscopy with a retrograde examination of the distal ileum, and push enteroscopy, underwent capsule endoscopy followed by intraoperative enteroscopy. RESULTS: Capsule endoscopy identified lesions in 100% of the patients with ongoing overt bleeding, 67% of the patients with previous overt bleeding, and 67% of the patients with obscure-occult bleeding. Angiectasias were the most common source of bleeding (n = 22). Capsule endoscopy showed the source of bleeding in 74.4% of all patients. The method was more effective in patients with ongoing bleeding. Compared with intraoperative enteroscopy sensitivity, specificity, and positive and negative predictive values of capsule endoscopy were 95%, 75%, 95%, and 86%, respectively. CONCLUSIONS: Capsule endoscopy has high sensitivity and specificity to detect a bleeding source in patients with obscure GI bleeding. Thus, wireless capsule endoscopy can be recommended as part of the routine work-up in patients with obscure GI bleeding.

Adolescent↗

PubMed2005

Diagnosis of liver cirrhosis: a comparison of modified ultrasound and laparoscopy in 100 consecutive patients.

BACKGROUND/GOALS: Liver cirrhosis, the final stage of chronic liver disease, is characterized by an unfavorable prognosis and an increased risk of hepatocellular carcinoma and also requires an appropriate management. Laparoscopy, the gold standard in the diagnosis of cirrhosis, is hampered by its invasiveness. Therefore, a noninvasive method for diagnosing liver cirrhosis would be of great benefit. STUDY: A consecutive series of 100 patients, sent to our gastroenterological unit for diagnostic laparoscopy, underwent a standardized ultrasonographic examination prior to laparoscopy. RESULTS: Conventional ultrasonographic examination revealed a sensitivity of 55% and a specificity of 86% in the diagnosis of cirrhosis. Considering the assessment of the transmission of heart pulsation on the liver surface, the corresponding values improved by increasing to 85% and 93%. CONCLUSION: Evaluating the transmission of heart pulsation on the liver surface improves the ability of ultrasound to diagnose liver cirrhosis; therefore, it should be an integral part of routine sonographic examination of the liver.

Adult↗

PubMed2005

Palliation of nonresectable bile duct cancer: improved survival after photodynamic therapy.

OBJECTIVES: Preliminary uncontrolled studies of photodynamic therapy (PDT) of bile duct cancer (BDC) have shown astonishingly good results in the reduction of cholestasis, improvement of life quality, and potential improvement of survival time. Therefore, we investigated the influence of PDT on survival time in advanced BDC in a randomized controlled study. METHODS: Thirty-two patients with nonresectable BDC were randomized. In the PDT group 48 h after intravenous application of 2 mg/kg body weight of Photosan-3((R)), light activation was performed. In the control group, patients were treated with endoprostheses but no PDT. RESULTS: PDT group and the control group were comparable due to age, gender, performance status, bilirubin level, and BDC stage (Bismuth classification). The median survival time after randomization was 7 months for the control group and 21 months for the PDT group (p= 0.0109). In half of the initially percutaneously treated patients, we could change from percutaneous to transpapillary drainage after PDT. Four patients showed infectious complications after PDT versus one patient in the control group. DISCUSSION: PDT is minimally invasive but shows a considerable postinterventional cholangitis rate. PDT has the potential to result in a changeover of current palliative treatment of BDC.

Aged↗

PubMed2004

High frequency of colorectal adenoma in patients with duodenal adenoma but without familial adenomatous polyposis.

BACKGROUND: Duodenal adenomas are extremely common in patients with familial adenomatous polyposis. However, it is uncertain whether patients with duodenal adenomas without familial adenomatous polyposis are at greater risk for colorectal neoplasia and, therefore, should routinely undergo surveillance colonoscopy. The aim of this study was to determine whether there is a correlation between non-papillary duodenal adenoma without familial adenomatous polyposis and colorectal adenoma. METHODS: Twenty-five patients with non-papillary duodenal adenomas without familial adenomatous polyposis, seen from January 1990 to April 2003, were retrospectively evaluated. RESULTS: Non-papillary duodenal polyps were diagnosed by endoscopy in the 25 patients. Of these, 21 underwent colonoscopy and one underwent proctoscopy. The mean age of these 22 patients (12 women, 10 men) was 69 years (range 50-83 years). Sixteen of the 22 patients (72.7%) with duodenal adenomas had associated colorectal adenomas. A total of 38 adenomas and one colorectal cancer were detected. The mean size of the polyps was 6.2 mm (range 3-15 mm). The adenomas were removed by snare excision or with a biopsy forceps. CONCLUSIONS: Based on the results of this uncontrolled, retrospective study, the frequency of colorectal adenomas in patients with duodenal polyps without familial adenomatous polyposis appears to be increased compared with the general population. All patients with duodenal polyps should undergo surveillance colonoscopy for colorectal adenomas. A prospective study to definitively establish the frequency of colorectal adenomas in these patients is warranted.

Adenoma, Villous↗

PubMed2003

Prospective, randomized, single-center trial comparing 3 different 10F plastic stents in malignant mid and distal bile duct strictures.

BACKGROUND: The aim of this study was to determine whether patency rates differ with respect to the material, design, and surface texture of 3 different plastic stents. METHODS: A total of 120 patients (median age 70.5 years; interquartile range 62-78 years) with malignant mid or distal bile duct strictures, seen between March 1996 and May 1999, were prospectively randomized to receive a 10F polyurethane stent, a Teflon Tannenbaum stent, or a hydrophilic hydromer-coated polyurethane stent. The primary study outcome measure was the interval between stent insertion and the first episode of clogging (or the presence of jaundice at death without stent exchange). All 3 types of stent were studied by scanning electron microscopy before insertion. RESULTS: A total of 19 patients were excluded from long-term follow-up. Median duration of stent patency was 76 days overall (interquartile range 29-150 days) and 76 (interquartile range 30-110) days for hydrophilic hydromer-coated polyurethane, 108 (interquartile range 33-186) days for 10F polyurethane, and 58 (interquartile range 21-188) days for Teflon Tannenbaum stents. There were no statistically significant differences among stent types. The hydrophilic hydromer-coated stent had the smoothest surface, as visualized by scanning electron microscopy. CONCLUSIONS: No significant differences in the patency of 3 types of stents were detected in this randomized trial. In particular, the hydrophilic hydromer-coated plastic stent did not provide clinical advantages despite its smooth surface.

Aged↗

PubMedDate not supplied

Self-expanding metal stents versus plastic prostheses in the palliation of malignant dysphagia: long-term outcome of 153 consecutive patients.

BACKGROUND: Malignant dysphagia due to esophagogastric cancer is associated with poor overall prognosis. Placements of self-expandable metal stents or plastic tubes are established methods as palliative treatment options. As an alternative and/or complementary therapy, radiologic techniques (external beam radiation/brachytherapy) and locally endoscopic techniques (laser, APC-beamer, PDT) are often used. STUDY AND GOALS: Retrospective trial of 153 patients treated in our department between 1993 and 2001. Forty-five patients received a plastic tube (Group A) and 108 patients were treated with metal stents (Group B). Both groups were compared for improvement of dysphagia score, survival, recurrent dysphagia and complications. RESULTS: Stent placement was successful in 41 of 45 (93%) patients of Group A and 107 of 108 (99%) of Group B. The median dysphagia score improved significantly in Group A (from 3.03 to 1.55, P = 0.010) and Group B (from 2.77 to 1.44, P = 0.009). Recurrent dysphagia was noted in 12 of 45 (27%) patients of Group A and 27 of 108 (25%) patients of Group B. Median survival time after stent insertion was 78 days (Group A) and 113 days (Group B). Overall complications occurred in 15 of 45 (33%) patients of Group A and 28 of 108 (26%) patients of Group B. However, significantly (P = 0.05) more major complications were seen in Group A than in Group B (22% vs. 9%). CONCLUSIONS: Our results indicate a marginal clinical benefit for metal stents versus plastic tubes in malignant dysphagia in the long run. However, metal stents seem to be safer and associated with a prolonged improvement of dysphagia score.

Adenocarcinoma↗

PubMedDate not supplied

Ceftriaxone is twice as cost-effective as standard therapy in biliary tract infection.

BACKGROUND/AIMS: Various antibiotics, mainly cephalosporins and broad-spectrum penicillins, are indicated in biliary tract infection. The primary endpoint was to compare the cost-effectiveness of ceftriaxone (Rocephin) 1 g once daily vs. standard therapy two or three times daily. METHODOLOGY: A prospective multicenter observational study, matched-pair analysis of 902 patients receiving ceftriaxone or standard therapy (second-generation cephalosporin, broad-spectrum penicillin or a combination of aminopenicillin and beta-lactamase inhibitor) in 75 hospitals yielded 173 pairs matched for definite risk criteria. Both groups received comparable accompanying endoscopic antiobstructive treatment. Cost parameters included primary antibiotic purchase, total antibiotic purchase (including combination and second-line drugs), and infusion preparation and administration. RESULTS: 87.9% of patients in the ceftriaxone group vs. 73.4% in the standard group received antibacterial monotherapy, for 7.5 vs. 9.1 days respectively (p=0.001). Therapy was equally effective in both groups. Overall treatment costs, including antibiotic purchase and infusion preparation/administration, were 170.84 vs. 320.46, respectively (p=0.0001). CONCLUSIONS: Ceftriaxone 1 g once daily is approximately twice as cost-effective as standard therapy in biliary tract infection: lower concomitant medication costs, a shorter treatment course, and lower antibiotic administration costs achieved an approximate 50% saving.

Anti-Bacterial Agents↗

PubMedDate not supplied

Endoscopic Doppler ultrasound after injection therapy for peptic ulcer hemorrhage.

BACKGROUND/AIMS: A positive Doppler signal in endoscopic Doppler ultrasound at index endoscopy predicts a high risk for rebleeding from peptic ulcer. The aim of this study was to evaluate if a negative Doppler status immediately after injection therapy may exclude a rebleeding from peptic ulcer in a high-risk cohort. METHODOLOGY: Twenty consecutive patients (pts) (age: 68 (33-91) yrs; 11 female) with peptic ulcer bleeding were enrolled. All patients with an actively bleeding ulcer and those with a non-actively bleeding, but Doppler-positive ulcer were treated by injection of adrenaline (1:10,000 dilution). Treatment was performed during index endoscopy until the Doppler status was negative. Patients were followed-up clinically and endoscopically (including Doppler ultrasound) for bleeding recurrence. RESULTS: Patients were treated by injection of 12 (6 to 20) mL of adrenaline solution until Doppler scan was negative. During follow-up four pts (20%) had a clinically overt rebleeding episode. At control endoscopy three ulcers were actively bleeding and another two were Doppler positive without rebleeding (total: five of eighteen (27.7%) Doppler-positive ulcers). Two of the twenty pts required surgical therapy due to rebleeding (10%). CONCLUSIONS: A negative endoscopic Doppler status immediately after injection therapy is not helpful to identify patients with no risk for rebleeding from peptic ulcer.

Adult↗