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Featured researches published by Ronnie Pimentel.


The American Journal of Gastroenterology | 1999

Endoscopic ultrasound cannot determine suitability for esophagectomy after aggressive chemoradiotherapy for esophageal cancer.

Gregory Zuccaro; Thomas W. Rice; John R. Goldblum; Sharon V. Medendorp; Mark Becker; Ronnie Pimentel; Laura Gitlin; David J. Adelstein

OBJECTIVE:Endoscopic ultrasound (EUS) provides important information in the initial staging of patients with esophageal cancer. With recent modifications in chemoradiotherapy protocols, a significant number of patients have no residual tumor at esophagectomy. The high surgical morbidity and mortality might be avoided if complete response to chemoradiotherapy could be predicted. Previously published clinical trials, with relatively small patient numbers, have suggested that EUS may accurately stage esophageal cancer after chemoradiotherapy. The aim of this study was to verify the accuracy of EUS in staging esophageal cancer after effective chemoradiotherapy.METHODS:EUS staging was performed before and after concurrent cisplatin, 5-fluorouracil, and hyperfractionated radiotherapy in 59 patients with newly diagnosed esophageal cancer. All patients underwent subsequent esophagectomy and pathological staging. The accuracy of preoperative, postchemoradiotherapy EUS was evaluated in a retrospective fashion by comparison to pathological staging.RESULTS:After chemoradiotherapy, 18 patients (31%) had no residual disease at pathological staging (T0N0). However, EUS correctly predicted complete response to chemoradiotherapy (T0N0) in only three patients (17%). The accuracy of postchemoradiotherapy EUS for pathological T stage was only 37%, and its sensitivity for N1 disease was only 38%. EUS was unable to distinguish postradiation fibrosis and inflammation from residual tumor.CONCLUSION:When aggressive preoperative chemoradiotherapy is provided to patients with esophageal cancer, the predictive value of postchemoradiotherapy EUS is inadequate for use in clinical decision making.


Surgical Endoscopy and Other Interventional Techniques | 2008

Outcome of endoscopic balloon dilation of strictures after laparoscopic gastric bypass

Andrew Ukleja; Bianca B. Afonso; Ronnie Pimentel; Samuel Szomstein; Raul J. Rosenthal

ObjectiveStricture formation at the gastrojejunal anastomosis is a relatively common complication after laparoscopic Roux-en-Y gastric bypass (LRYGB). The objective of this study was to report the incidence of stomal strictures after LRYGB in our institution and report our experience with their management by endoscopic balloon dilatation.MethodsThis is a retrospective study of 1012 patients who underwent LRYGB from January 2001 to May 2004. Patients with nausea and vomiting after the surgery, suspected of having gastrojejunal (GJ) anastomotic stricture, had upper endoscopy. Stomas less than 10 mm in diameter, or those not allowing passage of the scope were considered significant strictures and were treated with balloon dilations. Dilations were performed with a through-the-scope (TTS) balloon, with sizes ranging from 6 to 18 mm. The following data were collected from these patients: age, sex, body mass index (BMI), comorbidities, size of balloon catheter, time from surgery until symptoms onset, number of endoscopies needed to relief symptoms, and complications of the procedure.ResultsSixty-one patients (46 females and 15 males) were found to have anastomotic strictures, corresponding to an incidence of 6%. In total, 134 upper endoscopies were performed, with 128 dilatations. The average age was 41.7 years (range: 19–68 years); mean preoperative BMI was 45 kg/m2 (range: 42–61 kg/m2). Mean time from surgery to symptoms onset was 2 months (range: 1–6 months). The number of dilations per patient was as follows: a single dilation in 28% of patients, two dilations in 33%, three dilations in 26%, four dilations in 11.5%, and five dilations in 1.5% of patients. All the patients responded to dilation without need for formal surgical revision. However, after balloon dilatation three patients (4.9%), all females, had bowel perforation by radiological criteria (free air on X-ray), which corresponded to 2.2% of all dilatations. The maximum balloon size used in this group was 13.5 mm. All three patients had exploratory laparoscopy without finding of perforation site. They were treated with bowel rest, intravenous antibiotics for 7 days, and drain placement. No factors were identified to predict a risk of perforation.ConclusionThis is the largest study to evaluate the outcome of endoscopic dilatations of GJ strictures after RYGB. Endoscopic balloon dilation is a safe and effective treatment for anastomotic strictures. However, it carries a small risk of perforation. Further case studies are needed to determine risk factors for perforation and if the patients can be managed conservatively in this setting.


United European gastroenterology journal | 2015

The safety of same-day CT colonography following incomplete colonoscopy with polypectomy

Luis F. Lara; Danny J. Avalos; Huan Huynh; Brenda Jimenez-Cantisano; Mariann Padron; Ronnie Pimentel; Tolga Erim; Alison Schneider; Andrew Ukleja; Albert Parlade; Fernando Castro

Background Concerns about the risk of bowel perforation for same-day computed tomography colonography (CTC) following an incomplete colonoscopy with polypectomy may lead to unnecessarily postponing the CTC. Objective The objective of this article is to describe the complications including colon perforations associated with same-day CTC in a cohort who had polypectomies but an incomplete colonoscopy. Design We conducted a retrospective study. Setting Our study took place in a single, tertiary referral center. Patients We studied consecutive patients who had CTC the same day as an incomplete colonoscopy with polypectomy. Interventions Interventions included optical colonoscopy (OC), endoscopic polypectomies, and same-day CTC. Main outcome measurements: Our main outcome measurements included perforation rate with long-term follow-up. Results A total of 3% of patients undergoing colonoscopy from January 2008 to December 2012 had same-day CTC following incomplete OC, and 72 polypectomies were performed in 34 (or 17%) of these patients. Incomplete colonoscopies were due to colon tortuosity and looping (25), severe angulations (five), colon mass (two), colon stenosis (one), bradycardia (one). Fifty-three percent of the OCs were screening for colon neoplasia, 29% diagnostic and 18% were surveillance of colon polyps. Most polyps were ≤ 5 mm, and found in the left colon. There were no reported complications or perforations associated with same-day CTCs during short- and long-term follow-up. Limitations Limitations of our analysis included retrospective single-center design, small number of patients for the occurrence, referral to same-day CTC was not standardized, inability to establish safety of CTC for specific scenarios such as after complex polypectomies, strictures, or advanced IBD. Conclusions Radiologists’ apprehension to perform a CTC the same day as an incomplete colonoscopy following polypectomies because of perceived risk of perforation may be unfounded. More data are needed to determine the safety of same-day CTC in patients with high-risk findings during colonoscopy such as a stricture, severe IBD, and after complex polypectomies.


Endoscopy | 2014

Effect of a quality program with adverse events identification on airway management during overtube-assisted enteroscopy.

Luis F. Lara; Andrew Ukleja; Ronnie Pimentel; Roger Charles

BACKGROUND AND STUDY AIMS Adverse events associated with overtube-assisted enteroscopy are similar to those with routine endoscopy. Our endoscopy quality program identified a number of respiratory adverse events resulting in emergency resuscitation efforts. The aim is to report all adverse events identified by quality monitoring and outcomes of adverse events associated with overtube-assisted enteroscopy. METHODS A retrospective study used data prospectively obtained from consecutive patients undergoing overtube-assisted enteroscopy between December 2008 and July 2012. Patient characteristics, medical history, procedure indication, and procedure outcomes, including diagnosis, endoscopic therapy, and complications, were obtained. RESULTS In 432 overtube-assisted enteroscopies, 15 adverse events (most frequently hypoxemia, 9 /15, 60 %) occurred in 14 patients (3.2 % of total cohort; 12 were outpatients) mostly during antegrade enteroscopy. Four patients required endotracheal intubation and 4 /12 outpatients required intensive care. The procedure was aborted in 13 /14 patients, and only 1 of 10 patients scheduled for repeat antegrade enteroscopy returned. There was no mortality. Based on the frequency of adverse events, and in consultation with anesthesia providers, from August 2012 all antegrade overtube-assisted enteroscopies at our institution were done with general anesthesia. From then till September 2013, 145 antegrade and 52 retrograde overtube-assisted enteroscopies have been done, with no adverse events. CONCLUSIONS Monitoring of endoscopy practice identified adverse events associated with overtube-assisted enteroscopy. The peer-review prompted a change in practice: all patients undergoing antegrade overtube-assisted enteroscopy at our institution now have endotracheal intubation which has dramatically decreased the rate of respiratory adverse events. The impact of endoscopic quality measurements on practices, procedures, and outcomes will be of further interest.


Techniques in Coloproctology | 2014

Initial experience with a variable width and extreme tip angulation colonoscope

Luis F. Lara; Tolga Erim; Alison Schneider; Nicole Palekar; Brenda Jimenez; B. Murchie; Ronnie Pimentel; Roger Charles

Screening and surveillance colonoscopies can be affected by colon looping, angulations, diverticulosis, previous surgeries, body mass index, ability to sedate or type of sedation, bowel preparation, and female sex. Incomplete colonoscopies can be economically and emotionally costly and may result in decreased compliance with screening for colon neoplasia [1]. Instruments that improve the cecal intubation and adenoma detection rate, reduce the number of incomplete colonoscopies and improve patient satisfaction are desirable. Studies have shown that pediatric as well as variable stiffness colonoscopes achieve cecal intubation rates similar to standard colonoscopes, but possibly with less pain and with faster cecal intubation times [2, 3]. More recently, ultrathin colonoscopes have been reported to be better at negotiating acute luminal angulations, and patients may require less sedation than when standard colonoscopes are used. However, looping, difficulty removing larger polyps, and a higher ileal intubation failure rate have been reported [1, 4, 5]. We are, to the best of our knowledge, the first to report the ease of use and initial impressions with a newly available variable width colonoscope with extreme tip angulation capability.


Surgical Laparoscopy Endoscopy & Percutaneous Techniques | 2013

Hybrid endolaparoscopic management of biliary tract pathology in bariatric patients after gastric bypass: case report and review of a single-institution experience.

Ramon Vilallonga; Ronnie Pimentel; Raul J. Rosenthal

Obesity is the major risk factor in cholesterol crystal and gallstone formation. After an Roux-en-Y gastric bypass, biliary duct dilatation can appear and gallstone formation can cause biliary duct obstruction or gallstone pancreatitis. Management of this clinical situation can be challenging and many approaches have been reported. Endoscopic retrograde cholangiopancreatography plays an important role in the management of biliary duct obstruction in these patients. However, a previous modified anatomy makes this procedure technically difficult. For these reason, we describe our single-institution experience in the management of biliary duct obstruction utilizing a hybrid approach combining laparoscopy and flexible endoscopy.


Journal of Gastrointestinal and Digestive System | 2015

Mucinous Appendiceal Adenocarcinoma Presenting as Sister Mary Joseph Nodule: Case Report and Brief Review of Literature

Amareshwar Podugu; Alicia Alvarez; Ronnie Pimentel; Andrew Ukleja

Sister Mary Joseph nodule is a rare form of umbilical metastasis. Often, this is the only initial presenting sign for an underlying internal malignancy and is usually associated with poor prognosis. Although the gastrointestinal tract is the most common primary site, the majority of these metastases are from gastric and colorectal sites. We report a case of Sister Mary Joseph nodule in a patient with no GI complaints. Further evaluation led to the diagnosis of primary mucinous adenocarcinoma of the appendix. Primary mucinous adenocarcinoma of the appendix is a very rare tumor type that can give rise to umbilical metastases. To the best of our knowledge, only 3 cases of adenocarcinoma of the appendix metastasizing to the umbilicus have been reported in the medical literature.


Surgical Laparoscopy Endoscopy & Percutaneous Techniques | 2013

A hybrid endolaparoscopic therapy for the treatment of foreign bodies in the stomach with esophageal perforation.

Ramon Vilallonga; Ronnie Pimentel; Raul J. Rosenthal

Recently, the combination of a laparoscopic and endoscopic approach for surgical treatment has increased interest in minimally invasive surgery. Minimally invasive surgery has many advantages over traditional open procedures, and the management of foreign body ingestion is an interesting field in which the combination approach can be used. Herein, we describe the combined approach (laparoscopic and endoscopic) for removal of foreign bodies with the presence of esophageal perforation.


Gastrointestinal Endoscopy | 2004

Laparoscopy-assisted transgastrostomy ERCP after bariatric surgery: case report of a novel approach

Ronnie Pimentel; Amir Mehran; Samuel Szomstein; Raul J. Rosenthal


Archive | 2006

Irritable Bowel Syndrome

Ronnie Pimentel

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Luis F. Lara

University of Texas Southwestern Medical Center

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