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Dive into the research topics where Lyndon V. Hernandez is active.

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Featured researches published by Lyndon V. Hernandez.


Pancreas | 2002

Role of endoscopic ultrasound (EUS) and EUS-guided fine needle aspiration in the diagnosis and treatment of cystic lesions of the pancreas.

Lyndon V. Hernandez; Girish Mishra; Christopher Forsmark; Peter Draganov; John M. Petersen; Steven N. Hochwald; Stephen B. Vogel; Manoop S. Bhutani

Introduction and Aims Cystic neoplasms of the pancreas may be inadvertently treated as benign pseudocysts in clinical practice, often without the use of cytology, cyst tumor markers, or histopathology. We assessed the utility of EUS-guided fine-needle aspiration (EUS-FNA) to assist in the diagnosis and management of pancreatic cysts. Methodology All patients who had pancreatic cysts detected by EUS over a 24-month period were analyzed. Preoperative diagnosis was derived from an algorithm combining clinical history and endosonographic features. In selected cases, EUS-FNA was performed and cyst fluid aspirates were analyzed. Surgical specimens served as diagnostic standard. Results A total of 43 patients with pancreatic cysts underwent 45 EUS examinations. Surgical specimens were obtained from 9 patients (mucinous cystadenocarcinoma, 3; adenocarcinoma, 3; pancreatic endocrine tumor, 2; and benign cyst, 1); diagnostic EUS correctly predicted malignant cysts in 8/9 (88.9%). One case inaccurately interpreted by EUS as cystic neoplasm turned out to be a benign cyst on resection. Twenty-one patients underwent EUS-FNA. The cytologic interpretation was adenocarcinoma in 9.5% (2/21); suspicious for malignancy or atypical cells in 19.0% (4/21); benign in 66.6% (14/21); and insufficient cells in 4.8% (1/21). Conclusion The information gathered from clinical history and EUS, complemented by fluid analysis after EUS-guided FNA, predicts neoplastic pancreatic cysts and assists in decision-making for medical or surgical approach.


Journal of Gastroenterology | 2007

Usefulness of endoscopic ultrasound to diagnose the severity of chronic pancreatitis

Atsushi Irisawa; Kyoko Katakura; Hiromasa Ohira; Ai Sato; Manoop S Bhutani; Lyndon V. Hernandez; Masaru Koizumi

Endoscopic ultrasonography (EUS) is considered the most sensitive imaging method for the diagnosis of chronic pancreatitis (CP). Several investigators have shown that EUS findings of CP correlate with the presence of CP on endoscopic retrograde pancreatography (ERP). In general, for diagnosing CP using EUS, the presence or absence of the following EUS criteria is determined: hyperechoic foci, hyperechoic strands, lobularity, shadowing calcifications, cysts, hyperechoic duct margins, visible side branches, main pancreatic duct dilatation, and main pancreatic duct irregularity. Using these criteria, we reviewed the number of EUS criteria required to diagnose early CP and whether each EUS criterion correlates with the severity of CP on ERP. CP is likely when more than three criteria (for “early CP”) or more than five criteria (for “moderate CP”) are present. Moreover, each EUS criterion has its own importance at each ERP classification level. However, the obtained images can be operator dependent, and interobserver variability may affect interpretation of CP by EUS. Therefore, we performed a quantitative computer analysis of parenchymal echogenicity and compared it with the EUS diagnosis of CP so that the diagnosis of CP on the basis of EUS criteria could be objectively supported by the quantitative analysis of EUS images. In conclusion, EUS can objectively distinguish between a normal pancreas and CP, and can be used to evaluate the severity of the CP. EUS is a useful modality for diagnosing CP and is relatively less invasive than other available modalities.


Best Practice & Research in Clinical Gastroenterology | 2010

EUS in the diagnosis of early-stage chronic pancreatitis

Lyndon V. Hernandez; Marc F. Catalano

Chronic pancreatitis (CP) is a progressive inflammatory disease that is difficult to diagnose due to the paucity of a diagnostic gold standard. For almost two decades, early-stage CP has been recognised in the context of endoscopic ultrasound (EUS) when a patient presents with typical pancreatic-type pain, normal conventional imaging examinations, and subtle findings of CP by EUS. Whether these EUS findings represent true early-stage CP that will progress or whether they are false positive findings remain unclear. The key to enhancing the diagnostic precision of EUS in CP is to use objective, widely-accepted criteria that are reproducible. The Rosemont Criteria is a significant step towards achieving this goal and needs to be validated in conjunction with long-term studies of early-stage CP.


World Journal of Gastrointestinal Endoscopy | 2013

Malpractice claims for endoscopy.

Lyndon V. Hernandez; Dominic Klyve; Scott E. Regenbogen

AIM To summarize the magnitude and time trends of endoscopy-related claims and to compare total malpractice indemnity according to specialty and procedure. METHODS We obtained data from a comprehensive database of closed claims from a trade association of professional liability insurance carriers, representing over 60% of practicing United States physicians. Total payments by procedure and year were calculated, and were adjusted for inflation (using the Consumer Price Index) to 2008 dollars. Time series analysis was performed to assess changes in the total value of claims for each type of procedure over time. RESULTS There were 1901 endoscopy-related closed claims against all providers from 1985 to 2008. The specialties include: internal medicine (n = 766), gastroenterology (n = 562), general surgery (n = 231), general and family practice (n = 101), colorectal surgery (n = 87), other specialties (n = 132), and unknown (n = 22). Colonoscopy represented the highest frequencies of closed claims (n = 788) and the highest total indemnities (


Gastrointestinal Endoscopy | 2010

Anatomic-manometric correlation of the upper esophageal sphincter: a concurrent US and manometry study.

Lyndon V. Hernandez; Kulwinder S. Dua; Sri Naveen Surapaneni; Tanya Rittman; Reza Shaker

54 093 000). In terms of mean claims payment, endoscopic retrograde cholangiopancreatography (ERCP) ranked the highest (


northeast bioengineering conference | 2014

Pilot clinical studies of long duration, low intensity therapeutic ultrasound for osteoarthritis

Matthew D. Langer; Vanessa Levine; Rebecca M. Taggart; George K. Lewis; Lyndon V. Hernandez; Ralph Ortiz

374  794) per claim. Internists had the highest number of total claims (n = 766) and total claim payment (


Gastrointestinal Endoscopy | 2013

Longitudinal assessment of colonoscopy quality indicators: a report from the Gastroenterology Practice Management Group

Lyndon V. Hernandez; Thomas M. Deas; Marc F. Catalano; Nalini M. Guda; Lin Huang; Scott R. Ketover; Kyle P. Etzkorn; Kumar Gutta; Steve J. Morris; Michael J. Schmalz; Dominic Klyve; John I. Allen

70  730  101). Only total claim payments for colonoscopy and ERCP seem to have increased over time. Indeed, there was an average increase of 15.5% per year for colonoscopy and 21.9% per year for ERCP after adjusting for inflation. CONCLUSION There appear to be differences in malpractice coverage costs among specialties and the type of endoscopic procedure. There is also evidence for secular trend in total claim payments, with colonoscopy and ERCP costs rising yearly even after adjusting for inflation.


Journal of the Acoustical Society of America | 2013

Wearable long duration ultrasound therapy pilot study in rotator cuff tendinopathy

George K. Lewis; Lyndon V. Hernandez; Ralph Ortiz

BACKGROUND The pharyngoesophageal segment commonly referred to as the upper esophageal sphincter (UES) generates a high-pressure zone (HPZ) between the pharynx and the esophagus. However, the exact anatomical components of the UES-HPZ remain incompletely determined. OBJECTIVE To systematically define the US signature of various components of the pharyngoesophageal junction and to determine how these structures contribute to the development of the UES-HPZ. DESIGN Prospective, experimental study. SETTING Tertiary Academic Medical Center. PATIENTS This study involved 18 healthy volunteers. INTERVENTION We studied 5 participants by using a high-frequency US miniprobe (US-MP) and concurrent fluoroscopy and another 13 participants by using the US-MP and concurrent manometry. MAIN OUTCOME MEASUREMENTS Relative contribution of various muscles in the UES-HPZ. RESULTS Manometrically, the UES-HPZ had a median length of 4.0 cm (range 3.0-4.5 cm). A C-shaped muscle, believed to represent the cricopharyngeus muscle, was observed for a median length of 3.5 cm (range 2.0-4.0 cm). The oval configuration representing the esophageal contribution to the UES was seen in 10 of 13 participants (77%) at the distal HPZ (esophagus to UES transition zone). The flat configuration of the inferior constrictor muscle was noted in 7 of 13 participants (54%) at the proximal HPZ (UES to pharynx transition zone). There were 4 to 5 wall layers versus 3 layers in the distal and proximal HPZ, respectively. The mean (+/- SD) muscle thickness was relatively constant along the length of the UES-HPZ. LIMITATIONS Air artifacts in the UES-HPZ. CONCLUSION The configuration and layers of the UES-HPZ vary along its length. The upper esophagus is a significant contributor to the distal UES-HPZ.


Gastrointestinal Endoscopy | 2004

Lymph sampling and lymphangiography via EUS-guided transesophageal thoracic duct puncture in a swine model

Vinod K. Parasher; Lyndon V. Hernandez; Robert F. LeVeen; Christopher R.J. Mladinich; Venkatesh Nonabur; Manoop S. Bhutani

Osteoarthritis is one of the leading causes of disability in the aging population. Long duration, low intensity therapeutic ultrasound has had promising impact in animal models to slow the progression of the disease and provide joint relief. Two pilot studies were conducted using a novel, wearable platform for delivering ultrasound to evaluate the potential clinical benefits of ultrasound therapy on knee osteoarthritis. There was a pain reduction effect from using ultrasound, as high as fifty two percent in one study. As well, initial data demonstrates that mobility may be increased for patients experiencing mild to moderate arthritis of the knee.


Journal of Ultrasound in Medicine | 2001

Endosonographic features of a granular cell tumor of the colon.

Atsushi Irisawa; Lyndon V. Hernandez; Manoop S. Bhutani

BACKGROUND There is increasing demand for colonoscopy quality measures for procedures performed in ambulatory surgery centers. Benchmarks such as adenoma detection rate (ADR) are traditionally reported as static, one-dimensional point estimates at a provider or practice level. OBJECTIVE To evaluate 6-year variability of ADRs for 370 gastroenterologists from across the nation. DESIGN Observational cross-sectional analysis. SETTING Collaborative quality metrics database from 2007 to 2012. PATIENTS Patients who underwent colonoscopies in ambulatory surgery centers. INTERVENTIONS Colonoscopy. MAIN OUTCOME MEASUREMENTS The number of colonoscopies with an adenomatous polyp divided by the total number of colonoscopies (ADR-T), inclusive of indication and patients sex. RESULTS Data from 368,157 colonoscopies were included for analysis from 11 practices. Three practice sites (5, 8, and 10) were significantly above and 2 sites (3, 7) were significantly below mean ADR-T, with a 95% confidence interval (CI). High-performing sites had 9.0% higher ADR-T than sites belonging to the lowest quartile (P < .001). The mean ADR-T remained stable for 9 of 11 sites. Regression analysis showed that the 2 practice sites where ADR-T varied had significant improvements in ADR-T during the 6-year period. For each, mean ADR-T improved an average of 0.5% per quarter for site 2 (P = .001) and site 3 (P = .021), which were average and low performers, respectively. LIMITATIONS Summary-level data, which does not allow cross-reference of variables at an individual level. CONCLUSION We found performance disparities among practice sites remaining relatively consistent over a 6-year period. The ability of certain sites to sustain their high-performance over 6 years suggests that further research is needed to identify key organizational processes and physician incentives that improve the quality of colonoscopy.

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Marc F. Catalano

Medical College of Wisconsin

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Nalini M. Guda

University of Wisconsin-Madison

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Joseph E. Geenen

Medical College of Wisconsin

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Manoop S. Bhutani

University of Texas MD Anderson Cancer Center

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Manoop S Bhutani

University of Texas Medical Branch

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Michael J. Schmalz

Medical College of Wisconsin

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Atsushi Irisawa

University of Texas Medical Branch

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