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Dive into the research topics where Mark E. Benson is active.

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Featured researches published by Mark E. Benson.


Gastrointestinal Endoscopy | 2010

Colonoscopy training in gastroenterology fellowships: determining competence

Bret J. Spier; Mark E. Benson; Patrick R. Pfau; Gregory Nelligan; Michael R. Lucey; Eric A. Gaumnitz

BACKGROUND Although 140 colonoscopies is the recommended minimal requirement for gastroenterology fellows, it is unclear whether this minimum is a surrogate for competence. OBJECTIVE To assess whether 140 colonoscopies is an adequate threshold to determine > or =90% colonoscopy performance independence. DESIGN Retrospective analysis on a database constructed for quality control/improvement. SETTING Gastroenterology fellowship training program at a veterans hospital. PATIENTS Consecutive patients who underwent colonoscopy primarily for symptoms, previous polyps, or family history of cancer (a minority were performed for screening only) from April 2007 to September 2008. This study involved 11 gastroenterology fellows who performed 770 colonoscopies during 18 individual month-long rotations. INTERVENTION Assessment of various procedure-related parameters. MAIN OUTCOME MEASUREMENTS Determining when > or =90% independence in colonoscopy performance was reached. RESULTS Total colonoscopy time, time to cecal intubation, withdrawal time, and independent completion rates all significantly improved when first and third years of training were compared (P < .001 for all comparisons). The adenoma detection rate did not change between years of training. Independent completion was achieved in > or =90% of cases for all fellows after 500 colonoscopies, whereas no fellow reached a > or =90% independent colonoscopy completion rate after 140 colonoscopies. LIMITATIONS Number of participants, single center. CONCLUSIONS Becoming a competent colonoscopist requires repeated practice. Our study suggests that, although there is variability between a trainees ability to become colonoscopy independent, 500 colonoscopies are likely required to ensure reliable (> or =90%) independent completion rates. Competency requires more than a single parameter.


The American Journal of Gastroenterology | 2010

A Comparison of Optical Colonoscopy and CT Colonography Screening Strategies in the Detection and Recovery of Subcentimeter Adenomas

Mark E. Benson; Parul Dureja; Deepak V. Gopal; Mark Reichelderfer; Patrick R. Pfau

OBJECTIVES:Evidence has shown that computerized tomographic colonography (CTC) and optical colonoscopy (OC) can detect advanced adenomas at an equal rate; however, a comparison of the subcentimeter adenoma detection has not been performed. The objective of this study is to compare CTC and OC screening programs, with a focus on the detection and recovery of subcentimeter adenomas.METHODS:In all, 1,700 screening OC examinations in average-risk patients were compared with 1,307 CTC examinations in similar patients drawn from the same referral pool completed in 2006–2008. The detection rate for adenomas ≤5 mm, 6–9 mm, and <10 mm with advanced histology were compared.RESULTS:In the OC group, 23.2% of patients had at least one adenoma removed; in the CTC screening group, 5.9% of patients had at least one adenoma detected and removed, P<0.001. There were significantly more ≤5 mm adenomas (detection rate 0.22, 378/1,700) detected by OC than by CTC (detection rate 0.04, 56/1,307), P<0.001. There were significantly more adenomas 6–9 mm (detection rate 0.12, 204/1,700) detected by OC than by CTC (detection rate 0.05, 67/1,307), with 70 patients with polyps of unknown histology in CTC surveillance, P<0.001. The number of advanced lesions <10 mm detected by OC (15/1,700) compared with CTC (4/1,307) were not significantly different, P=0.06. In the OC group, 27.1% of patients had non-adenomatous polyps removed; in the CTC group, 4.1% of patients had non-adenomatous polyps removed, P<0.001.CONCLUSIONS:(i) An OC screening program detects and recovers a significant four and a half fold greater number of non-advanced adenomas compared with a CTC screening program. (ii) The primary difference between screening with OC and CTC is the recovery and management of the subcentimeter adenoma.


Diagnostic and Therapeutic Endoscopy | 2012

Use of i-scan Endoscopic Image Enhancement Technology in Clinical Practice to Assist in Diagnostic and Therapeutic Endoscopy: A Case Series and Review of the Literature

Shawn Hancock; Erik Bowman; Jyothiprashanth Prabakaran; Mark E. Benson; Rashmi Agni; Patrick R. Pfau; Mark Reichelderfer; Jennifer M. Weiss; Deepak V. Gopal

Background. i-scan is a software-driven technology that allows modifications of sharpness, hue, and contrast to enhance mucosal imaging. It uses postimage acquisition software with real-time mapping technology embedded in the endoscopic processor. Aims. To review applications of i-scan technology in clinical endoscopic practice. Methods. This is a case series of 20 consecutive patients who underwent endoscopic procedures where i-scan image enhancement algorithms were applied. The main outcome measures were to compare mucosal lesions with high-definition white light endoscopy (HD-WLE) and i-scan image enhancement for the application of diagnostic sampling and therapy. Results. 13 cases involving the upper GI tract and 7 cases of the lower GI tract are included. For upper GI tract pathology i-scan assisted in diagnosis or therapy of Barretts esophagus with dysplasia, esophageal adenocarcinoma, HSV esophagitis, gastric MALT lymphoma, gastric antral intestinal metaplasia with dysplasia, duodenal follicular lymphoma, and a flat duodenal adenoma. For lower GI tract pathology i-scan assisted in diagnosis or therapy of right-sided serrated adenomas, flat tubular adenoma, rectal adenocarcinoma, anal squamous cell cancer, solitary rectal ulcer, and radiation proctitis. Conclusions. i-scan imaging provides detailed topography of mucosal surfaces and delineates lesion edges, which can directly impact endoscopic management.


The American Journal of Gastroenterology | 2014

Influence of Previous Night Call and Sleep Deprivation on Screening Colonoscopy Quality

Mark E. Benson; Ian Grimes; Deepak V. Gopal; Mark Reichelderfer; Anurag Soni; Holly Benson; Kerstin E. Austin; Patrick R. Pfau

OBJECTIVES:There are few studies evaluating the influence of sleep deprivation on endoscopic outcomes. To evaluate the effect of a previous night call on the quality of screening colonoscopies performed the following day.METHODS:Average-risk patients undergoing screening colonoscopies were included. Quality metrics were retrospectively compared between two groups of post-call colonoscopies and colonoscopies performed by the same individuals not on call the night before: those performed by gastroenterologists who were only on call the night prior and those performed by gastroenterologists who performed emergent on-call procedures the night prior.RESULTS:Between 1 July 2010 and 31 March 2012, 447 colonoscopies were performed by gastroenterologists who were on call only the night prior, 126 colonoscopies were performed by gastroenterologists who had completed on-call emergent procedures the night prior, and 8,734 control colonoscopies were completed. There was a lower percent of patients who were screened with adenomas detected in procedures performed by endoscopists who had performed emergent on-call procedures the night prior compared with the controls (30 vs. 39%, respectively; P=0.043). The mean withdrawal time for these colonoscopies was significantly longer than that for the control procedures (15.5 vs. 14.0 min; P=0.025). For the colonoscopies performed by endoscopists who were on call only the night prior, there was no significant difference in the percent of patients screened with adenomas detected compared with controls (42 vs. 39%, respectively; P=0.136).CONCLUSIONS:(1) Despite longer withdrawal times, being on call the night prior and performing an emergent procedure lead to a significant 24% decrease in the adenoma detection rates. (2) It is imperative for screening physicians to be aware of the influence of sleep deprivation on procedural outcomes and to consider altering their practice accordingly.


Diagnostic and Therapeutic Endoscopy | 2015

High Definition Colonoscopy Combined with i-SCAN Imaging Technology Is Superior in the Detection of Adenomas and Advanced Lesions Compared to High Definition Colonoscopy Alone

Erik Bowman; Patrick R. Pfau; Arnab Mitra; Mark Reichelderfer; Deepak V. Gopal; Benjamin S. Hall; Mark E. Benson

Background. Improved detection of adenomatous polyps using i-SCAN has mixed results in small studies. Utility of i-SCAN as a primary surveillance modality for colorectal cancer screening during colonoscopy is uncertain. Aim. Comparing high definition white light endoscopy (HDWLE) to i-SCAN in their ability to detect adenomas during colonoscopy. Methods. Prospective cohort study of 1936 average risk patients who had a screening colonoscopy at an ambulatory procedure center. Patients underwent colonoscopy with high definition white light endoscopy withdrawal versus i-SCAN withdrawal during endoscopic screening exam. Primary outcome measurement was adenoma detection rate for i-SCAN versus high definition white light endoscopy. Secondary measurements included polyp size, pathology, and morphology. Results. 1007 patients underwent colonoscopy with i-SCAN and 929 with HDWLE. 618 adenomas were detected in the i-SCAN group compared to 402 in the HDWLE group (p < 0.01). More advanced adenomas (≥10 mm) were found by i-SCAN, 79 versus 47 (p = 0.021) and based upon histology alone 37 versus 18 (p = 0.028). Conclusions. i-SCAN detected significantly more adenomas and advanced adenomas compared to high definition white light endoscopy.


Endoscopic ultrasound | 2014

Differentiating primary pancreatic lymphoma from adenocarcinoma using endoscopic ultrasound characteristics and flow cytometry: A case-control study

Eric A. Johnson; Mark E. Benson; Nalini M. Guda; Patrick R. Pfau; Terrence J. Frick; Deepak V. Gopal

Background: Primary pancreatic lymphoma (PPL) is a rare pancreatic neoplasm that is difficult to diagnose. PPL has a vastly different prognosis and treatment regimen than other pancreatic tumors; therefore, accurate diagnosis is vital. In this article, we describe the characteristic presentation, endoscopic ultrasound (EUS) features, and the role of fine-needle aspiration (FNA) in the diagnosis of PPL compared with pancreatic adenocarcinoma. Materials and Methods: This was a retrospective case-control study of 11 patients diagnosed with PPL via EUS between 2002 and 2011. The clinical and EUS features of the cases were then compared with age-matched controls with adenocarcinoma in a 1:3 ratio. Results: There were 11 patients with PPL and 33 with adenocarcinoma. At last follow-up, 7 of 11 PPL patients were alive, and 3 of 33-adenocarcinoma patients were alive (P < 0.001). The most common presenting symptoms for PPL were pain 73%, weight loss 45%, and jaundice 18%, while patients with adenocarcinoma presented with pain 52% (P = 0.3), weight loss 30% (P = 0.47) and jaundice 76% (P = 0.001). The EUS appearance was similar in the two groups in that ultrasound imaging of the pancreas lesions tended to be hypoechoic and heterogenous, but the PPL group was more likely to have peripancreatic lymphadenopathy (LAD) (64% vs. 18%, P = 0.008) and were larger (4.8 cm × 5.3 cm vs. 3.2 cm × 3.1 cm, P < 0.001). The PPL group was less likely to have vascular invasion (18% vs. 55%, P = 0.045) and less likely to be found in the head of the pancreas (36% vs. 85%, P = 0.004). FNA and cytology (without flow cytometry [FC]) made the diagnosis in 28% of PPL patients compared with 91% of adenocarcinoma patients (P = 0.002). In the PPL group, 7 of 11 FNA samples were sent for FC. If FC was added, then the diagnosis of PPL was increased to 100%. Conclusions: Compared with adenocarcinoma, pancreatic lymphoma has a better prognosis, is less likely to present with jaundice and less likely to have vascular invasion. PPL is more likely to be located outside the head of the pancreas and to include peripancreatic LAD, and is less likely to be diagnosed with cytology. The diagnostic accuracy of FNA for PPL is improved greatly with the addition of FC.


Diagnostic and Therapeutic Endoscopy | 2015

Comparison of Capsule Endoscopy Findings to Subsequent Double Balloon Enteroscopy: A Dual Center Experience

Amandeep S. Kalra; Andrew J. Walker; Mark E. Benson; Anurag Soni; Nalini M. Guda; Mehak Misha; Deepak V. Gopal

Background. There has been a growing use of both capsule endoscopy (CE) and double balloon enteroscopy (DBE) to diagnose and treat patients with obscure gastrointestinal blood loss and suspected small bowel pathology. Aim. To compare and correlate sequential CE and DBE findings in a large series of patients at two tertiary level hospitals in Wisconsin. Methods. An IRB approved retrospective study of patients who underwent sequential CE and DBE, at two separate tertiary care academic centers from May 2007 to December 2011, was performed. Results. 116 patients were included in the study. The mean age ± SD was 66.6 ± 13.2 years. There were 56% males and 43.9% females. Measure of agreement between prior capsule and DBE findings was performed using kappa statistics, which gave kappa value of 0.396 with P < 0.001. Also contingency coefficient was calculated and was found to be 0.732 (P < 0.001). Conclusions. Our study showed good overall agreement between DBE and CE. Findings of angioectasia had maximum agreement of 69%.


Clinical Gastroenterology and Hepatology | 2012

Fiscal Analysis of Establishment of a Double-Balloon Enteroscopy Program and Reimbursement

Mark E. Benson; Wendy Horton; Jill Gluth; Patrick R. Pfau; Sigurdur Einarsson; Michael R. Lucey; Anurag Soni; Mark Reichelderfer; Deepak V. Gopal

BACKGROUND & AIMS As double-balloon enteroscopy (DBE) programs continue to be established, further research is needed to assess their financial impact. We evaluated actual financial outcomes and compared them with estimated return on investment (ROI) projections for DBE. METHODS We retrospectively compared the predicted and actual financial results for outpatients referred for DBE at an academic tertiary referral center. RESULTS The ROI analysis was based on a 5-year time frame. The analysis projected a net present value of


Archive | 2019

Ingested Foreign Objects and Food Bolus Impactions

Mark E. Benson; Patrick R. Pfau

64,623 and an internal rate of return of 24.6%. The projected first-year volume was 52 outpatient cases; however, the actual experience was 20 outpatient cases. The predicted percent margin for these outpatient cases was 16.6%; the actual margin was 24.4%. After 37 months, 52 outpatient cases were completed, and the actual percent margin was 4.6%. Payer type had a significant influence on the financial outcomes when projected activity and actual activity were compared. CONCLUSIONS Institutions interested in establishing a DBE program should be aware of the financial implications of program establishment, which can be evaluated in a return on investment analysis. Payer mix significantly influences DBE reimbursement and collection rates.


Clinical Gastroenterology and Hepatology | 2018

Video-Based Assessments of Colonoscopy Inspection Quality Correlate With Quality Metrics and Highlight Areas for Improvement

Anna Duloy; Rena Yadlapati; Mark E. Benson; Andrew J. Gawron; Charles J. Kahi; Tonya Kaltenbach; Jessica McClure; Dyanna L. Gregory

Abstract Gastrointestinal foreign bodies are comprised of food bolus impactions and both intentionally and unintentionally ingested and inserted true foreign objects. This review covers diagnostic and therapeutic use of non-endoscopic and endoscopic methods in managing gastrointestinal foreign bodies. With flexible endoscopy being the primary treatment modality of gastrointestinal foreign bodies detailed attention is centered on the endoscopic success, techniques, equipment, and complications used for the management of food impactions and the varying types of true foreign bodies.

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Patrick R. Pfau

University of Wisconsin-Madison

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Deepak V. Gopal

University of Wisconsin-Madison

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Mark Reichelderfer

University of Wisconsin-Madison

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Anurag Soni

University of New Mexico

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Eric M. Nelsen

University of Wisconsin-Madison

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Michael R. Lucey

University of Wisconsin-Madison

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Eric A. Gaumnitz

University of Wisconsin-Madison

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Erik Bowman

University of Wisconsin-Madison

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Jennifer M. Weiss

University of Wisconsin-Madison

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