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Dive into the research topics where Santiago Horgan is active.

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Featured researches published by Santiago Horgan.


Annals of Surgery | 1999

Minimally invasive surgery for achalasia: an 8-year experience with 168 patients.

Marco G. Patti; Carlos A. Pellegrini; Santiago Horgan; Massimo Arcerito; Pablo Omelanczuk; Andrea Tamburini; Urs Diener; Thomas R. Eubanks; Lawrence W. Way

BACKGROUND Seven years ago, the authors reported on the feasibility and short-term results of minimally invasive surgical methods to treat esophageal achalasia. In this report, they describe the evolution of the surgical technique and the clinical results in a large group of patients with long follow-up. PATIENTS AND METHODS Between January 1991 and October 1998, 168 patients (96 men, 72 women; mean age 45 years, median duration of symptoms 48 months), who fulfilled the clinical, radiographic, endoscopic, and manometric criteria for a diagnosis of achalasia, underwent esophagomyotomy by minimally invasive techniques. Forty-eight patients had marked esophageal dilatation (diameter >6.0 cm). Thirty-five patients had a left thoracoscopic myotomy, and 133 patients had a laparoscopic myotomy plus a partial fundoplication. Follow-up to October 1998 was complete in 145 patients (86%). RESULTS Median hospital stay was 72 hours for the thoracoscopic group and 48 hours for the laparoscopic group. Eight patients required a second operation for recurrent or persistent dysphagia, and two patients required an esophagectomy. There were no deaths. Good or excellent relief of dysphagia was obtained in 90% of patients (85% after thoracoscopic and 93% after laparoscopic myotomy). Gastroesophageal reflux developed in 60% of tested patients after thoracoscopic myotomy and in 17% after laparoscopic myotomy plus fundoplication. Laparoscopic myotomy plus fundoplication corrected reflux present before surgery in five of seven patients. Patients with a dilated esophagus had excellent relief of dysphagia after laparoscopic myotomy; none required an esophagectomy. CONCLUSIONS Minimally invasive techniques provided effective and long-lasting relief of dysphagia in patients with achalasia. The authors prefer the laparoscopic approach for three reasons: it more effectively relieved dysphagia, it was associated with a shorter hospital stay, and it was associated with less postoperative reflux. Laparoscopic Heller myotomy and partial fundoplication should be considered the primary treatment for esophageal achalasia.


Journal of Laparoendoscopic & Advanced Surgical Techniques | 2001

Robots in Laparoscopic Surgery

Santiago Horgan; Daniel Vanuno

BACKGROUND The Da Vinci Robotic System became available at our institution in late August 2000. We decided to utilize this system to perform advanced laparoscopic procedures. METHODS This is a review of the status of robotics and its application in surgery. We report our experience using the Da Vinci system. RESULTS We have used the Da Vinci for 34 advanced laparoscopic cases: 7 gastric bypasses for morbid obesity, 9 Heller myotomies for achalasia, 11 donor nephrectomies, 2 gastrojejunostomies, and single cases of bilateral adrenalectomy, Nissen fundoplication, Toupet fundoplication, and cholecystectomy. No robot-related complications were noted. CONCLUSIONS This early experience suggests that robotic surgery is a safe and effective alternative to conventional laparoscopic surgery. We believe that robotic surgery, with its ability to restore the hand-eye coordination and three-dimensional view lost in laparoscopic surgery, will allow us to perform complex procedures with greater precision and confidence and better results.


Surgical Endoscopy and Other Interventional Techniques | 2003

A prospective analysis of 211 robotic-assisted surgical procedures

Mark A. Talamini; S. Chapman; Santiago Horgan; W.S. Melvin

Background: The Academic Robotics Group prospectively studied 211 robotically assisted operations to assess the safety and utility of robotically assisted surgery. Methods: All operations took place at one of four member institutions between June 2000 and June 2001 using the recently FDA-approved daVinci robotic system. A variety of procedures were undertaken, including antireflux surgery (69), cholecystectomy (36), Heller myotomy (26), bowel resection (17), donor nephrectomy (15), left internal mammery artery mobilization (14), gastric bypass (seven), splenectomy (seven), adrenalectomy (six), exploratory laparoscopy (three), pyloroplasty (four), gastrojejunostomy (two), distal pancreatectomy (one), duodenal polypectomy (one), esophagectomy (one), gastric mass resection (one), and lysis of adhesions (one). Results: Average operating room time was 188 min (range 45 to 387, SD = 83), surgical time 143 min (range 35 to 462, SD = 63), and robot time 90 min (range 12 to 235, SD = 47). Median length of stay was 1 day (range 0 to 37). There were 8 (4%) technical complications during procedures, five minor (four hook cautery dislodgement, one slipped robotic trocar) and three major (system malfunctions, two of which required conversion to standard laparoscopy). In all cases, technical problems caused only delay, without apparent altered outcome. There were medical/surgical complications in nine patients (4%). Six (3%) were considered major, including one death unrelated to the robotic procedure. Conclusions: The results of robotic-assisted surgery compare favorably with those of conventional laparoscopy with respect to mortality, complications, and length of stay. Robotic-assisted surgery is safe and effective and is a new reality for American surgery. The role of these devices in surgery will expand as the technology evolves.


Radiology | 2011

Estimation of Hepatic Proton-Density Fat Fraction by Using MR Imaging at 3.0 T

Takeshi Yokoo; Masoud Shiehmorteza; Gavin Hamilton; Tanya Wolfson; Michael E. Schroeder; Michael S. Middleton; Mark Bydder; Anthony Gamst; Yuko Kono; Alexander Kuo; Heather Patton; Santiago Horgan; Joel E. Lavine; Jeffrey B. Schwimmer; Claude B. Sirlin

PURPOSE To compare the accuracy of several magnetic resonance (MR) imaging-based methods for hepatic proton-density fat fraction (FF) estimation at 3.0 T, with spectroscopy as the reference technique. MATERIALS AND METHODS This prospective study was institutional review board approved and HIPAA compliant. Informed consent was obtained. One hundred sixty-three subjects (39 with known hepatic steatosis, 110 with steatosis risk factors, 14 without risk factors) underwent proton MR spectroscopy and non-T1-weighted gradient-echo MR imaging of the liver. At spectroscopy, the reference FF was determined from frequency-selective measurements of fat and water proton densities. At imaging, FF was calculated by using two-, three-, or six-echo methods, with single-frequency and multifrequency fat signal modeling. The three- and six-echo methods corrected for T2*; the two-echo methods did not. For each imaging method, the fat estimation accuracy was assessed by using linear regression between the imaging FF and spectroscopic FF. Binary classification accuracy of imaging was assessed at four reference spectroscopic thresholds (0.04, 0.06, 0.08, and 0.10 FF). RESULTS Regression intercept of two-, three-, and six-echo methods were -0.0211, 0.0087, and -0.0062 (P <.001 for all three) without multifrequency modeling and -0.0237 (P <.001), 0.0022, and -0.0007 with multifrequency modeling, respectively. Regression slope of two-, three-, and six-echo methods were 0.8522, 0.8528, and 0.7544 (P <.001 for all three) without multifrequency modeling and 0.9994, 0.9775, and 0.9821 with multifrequency modeling, respectively. Significant deviation of intercept and slope from 0 and 1, respectively, indicated systematic error. Classification accuracy was 82.2%-90.1%, 93.9%-96.3%, and 83.4%-89.6% for two-, three-, and six-echo methods without multifrequency modeling and 88.3%-92.0%, 95.1%-96.3%, and 94.5%-96.3% with multifrequency modeling, respectively, depending on the FF threshold. T2*-corrected (three- and six-echo) multifrequency imaging methods had the overall highest FF estimation and classification accuracy. Among methods without multifrequency modeling, the T2-corrected three-echo method had the highest accuracy. CONCLUSION Non-T1-weighted MR imaging with T2 correction and multifrequency modeling helps accurately estimate hepatic proton-density FF at 3.0 T.


The New England Journal of Medicine | 2013

Esophageal sphincter device for gastroesophageal reflux disease.

Robert A. Ganz; Jeffrey H. Peters; Santiago Horgan; Willem A. Bemelman; Christy M. Dunst; Steven A. Edmundowicz; John C. Lipham; James D. Luketich; W. Scott Melvin; Brant K. Oelschlager; Steven Schlack-Haerer; C. Daniel Smith; C. Christopher Smith; Dan Dunn; Paul A. Taiganides

BACKGROUND Patients with gastroesophageal reflux disease who have a partial response to proton-pump inhibitors often seek alternative therapy. We evaluated the safety and effectiveness of a new magnetic device to augment the lower esophageal sphincter. METHODS We prospectively assessed 100 patients with gastroesophageal reflux disease before and after sphincter augmentation. The study did not include a concurrent control group. The primary outcome measure was normalization of esophageal acid exposure or a 50% or greater reduction in exposure at 1 year. Secondary outcomes were 50% or greater improvement in quality of life related to gastroesophageal reflux disease and a 50% or greater reduction in the use of proton-pump inhibitors at 1 year. For each outcome, the prespecified definition of successful treatment was achievement of the outcome in at least 60% of the patients. The 3-year results of a 5-year study are reported. RESULTS The primary outcome was achieved in 64% of patients (95% confidence interval [CI], 54 to 73). For the secondary outcomes, a reduction of 50% or more in the use of proton-pump inhibitors occurred in 93% of patients, and there was improvement of 50% or more in quality-of-life scores in 92%, as compared with scores for patients assessed at baseline while they were not taking proton-pump inhibitors. The most frequent adverse event was dysphagia (in 68% of patients postoperatively, in 11% at 1 year, and in 4% at 3 years). Serious adverse events occurred in six patients, and in six patients the device was removed. CONCLUSIONS In this single-group evaluation of 100 patients before and after sphincter augmentation with a magnetic device, exposure to esophageal acid decreased, reflux symptoms improved, and use of proton-pump inhibitors decreased. Follow-up studies are needed to assess long-term safety. (Funded by Torax Medical; ClinicalTrials.gov number, NCT00776997.).


Surgical Endoscopy and Other Interventional Techniques | 2009

Natural orifice surgery: initial clinical experience

Santiago Horgan; John Cullen; Mark A. Talamini; Yoav Mintz; Alberto R. Ferreres; Garth R. Jacobsen; Bryan J. Sandler; Julie Bosia; Thomas J. Savides; David W. Easter; Michelle K. Savu; Sonia Ramamoorthy; Emily L. Whitcomb; Sanjay Kumar Agarwal; Emily S. Lukacz; Guillermo Domínguez; Pedro Ferraina

BackgroundNatural orifice translumenal endoscopic surgery (NOTES) has moved quickly from preclinical investigation to clinical implementation. However, several major technical problems limit clinical NOTES including safe access, retraction and dissection of the gallbladder, and clipping of key structures. This study aimed to identify challenges and develop solutions for NOTES during the initial clinical experience.MethodsUnder an Institutional Review Board (IRB)-approved protocol, patients consented to a natural orifice operation for removal of either the gallbladder or the appendix via either the vagina or the stomach using a single umbilical trocar for safety and assistance.ResultsNine transvaginal cholecystectomies, one transgastric appendectomy, and one transvaginal appendectomy have been completed to date. All but one patient were discharged on postoperative day 1 as per protocol. No complications occurred.ConclusionThe limited initial evidence from this study demonstrates that NOTES is feasible and safe. The addition of an umbilical trocar is a bridge allowing safe performance of NOTES procedures until better instruments become available. The addition of a flexible long grasper through the vagina and a flexible operating platform through the stomach has enabled the performance of NOTES in a safe and easily reproducible manner. The use of a uterine manipulator has facilitated visualization of the cul de sac in women with a uterus to allow for safe transvaginal access.


American Journal of Surgery | 2002

US experience with the LAP-BAND system

Christine J. Ren; Santiago Horgan; Jaime Ponce

Laparoscopic adjustable gastric banding is the most commonly performed operation for morbid obesity in Europe and Australia and has been shown to result in significant long-term weight loss. The US Food and Drug Administration (FDA)-monitored clinical trial results with the LAP-BAND system (INAMED Health, Santa Barbara, CA) did not reproduce the results of studies performed elsewhere in the world. This article reviews data from the first and second FDA clinical trials as well as data from continuing US clinical experience. Four American surgeons at 4 centers have performed more than 500 LAP-BAND procedures not included in the first 2 FDA clinical trials. Of these patients, 115 have been followed for at least 9 months, and 43 have been followed for at least 12 months. A retrospective analysis of prospective data gathered from these patients is presented. The percent excess weight loss was 35.6% at 9 months and 41.6% at 12 months. The average body mass index decreased from 47.5 to 38.8 in 9 months and from 47.5 to 37.3 in 12 months. There were no deaths related to the insertion of the device. Of 15 complications requiring operative management (13%) in 12 patients, there were 8 port displacements or tubing breaks (7%), 2 elective explantations (2%), 2 cases of gastric prolapse (2%), 1 gastric pouch dilatation (<1%), 1 port abscess (<1%), and 1 hemorrhage (<1%). Clinical experience with the LAP-BAND system in the United States shows the device to be a safe and effective treatment for morbid obesity, with results comparable to the international data. The combination of proper surgical technique and close patient follow-up with frequent band adjustments, performed in a comprehensive bariatric program setting, may make the LAP-BAND system a powerful surgical tool in the treatment of morbid obesity.


Transplantation | 2002

Robotic-assisted laparoscopic donor nephrectomy for kidney transplantation

Santiago Horgan; Daniel Vanuno; Pierpaolo Sileri; Luca Cicalese; Enrico Benedetti

Background. Minimally invasive laparoscopic nephrectomy is a well-established alternative to open surgery in living donors for kidney transplantation. Donor mortality and morbidity rates as well as recipient outcome are comparable to the open approach. Furthermore, the procedure is associated with reduced donor discomfort, faster recovery, and improved cosmetic results. Recently, an advanced robotic system for laparoscopic surgery was approved for use in the United States. This system allows a greater freedom of movement and recreates the hand–eye coordination and three-dimensional vision that is lost in standard laparoscopic procedures. Methods. We report the first 12 successful cases of robotic-assisted laparoscopic living donor nephrectomy performed using the da Vinci Surgical System (Intuitive Surgical, Mountain View, CA). Results. Our initial experience has shown that the system allows the performance of donor nephrectomy in a safe and accurate fashion. Conclusions. As technology continues to evolve, robotic-assisted surgery has the potential to become a widely used attractive alternative to standard laparoscopic donor nephrectomy.


Journal of The American College of Surgeons | 1999

An objective scoring system for laparoscopic cholecystectomy

Thomas R. Eubanks; Ronald H Clements; Dieter Pohl; Noel N. Williams; Douglas C. Schaad; Santiago Horgan; Carlos A. Pellegrini

BACKGROUND Direct observation with structured criteria for performance is the most reliable and valid method of assessing technical skill during operative procedures. We developed such a system to evaluate technical performance during a laparoscopic cholecystectomy. The reliability and validity of the system were tested by analyzing the correlation among three observers in a multicenter study and comparing performance with years of surgical experience. STUDY DESIGN Thirty consecutive cases of laparoscopic cholecystectomy were recorded on videotape, 10 from each of 3 institutions. Independent scores were generated by three observers examining each of the videotapes, providing a total of 90 scores. Points were awarded for successful completion of each of 23 different steps required to perform a laparoscopic cholecystectomy. Error points were tabulated based on the frequency and relative severity of each of 21 potential technical mistakes during the operation. The final score was assumed to be a relative measure of technical skill and was derived by subtracting error points from points awarded for completion of each step of the procedure. Pearson correlation coefficients were used to assess agreement among examiners and correlation with year of surgical experience. RESULTS Agreement in final scores among the three observers was excellent (r = 0.74-0.96) despite the fact that one observer assigned significantly fewer error points. Correlation between year of experience and two-handed technique scoring was good (r = 0.5, p = 0.057), but the correlation between experience and one-handed technique scores was poor (r = 0.02). CONCLUSIONS The technical skills required to perform laparoscopic cholecystectomy can reliably be measured using this tool. This method can be used to track the learning curve of surgeons in training, evaluate the efficacy of alternative training tools, and provide a means of self-assessment for the trainee.


Journal of Gastrointestinal Surgery | 2005

Robotic-assisted heller myotomy versus laparoscopic heller myotomy for the treatment of esophageal achalasia: multicenter study

Santiago Horgan; Carlos Galvani; Maria V. Gorodner; Pablo Omelanczuck; Fernando Elli; Federico Moser; Luis Durand; Miguel Caracoche; Jorge Nefa; Sergio Bustos; Phillip Donahue; Pedro Ferraina

Laparoscopic Heller myotomy (LHM) has become the standard treatment option for achalasia. The incidence of esophageal perforation reported is about 5%–10%. Robotically assisted Heller myotomy (RAHM) is emerging as a safe alternative to LHM. Data comparing the two approaches are scant. The aim of this study was to compare RAHM with LHM in terms of efficacy and safety for treatment of achalasia. A total of 121 patients underwent surgical treatment of achalasia at three institutions. A retrospective review of prospectively collected perioperative data was performed. Patients were divided into two groups: group A (RAHM), 59 patients, and group B (LHM), 62 patients. All the operations were completed using minimally invasive techniques. There were 63 women and 58 men, with a mean age of 45 ±19 years (14–82 years). Fifty-one percent of patients in group A and 95% of patients in group B reported weight loss. Duration of symptoms was equal for both groups. Dysphagia was the main complaint in both groups (P = NS). There was no difference in preoperative endoscopic treatment in both groups (44% versus 27%, P = NS). Operative time was significantly shorter for LHM in the first half of the experience (141 ± 49 versus 122 ± 44 minutes, P < .05). However, in the last 30 cases there was no difference in operative time between the groups (P = NS). Intraoperative complications (esophageal perforation) were more frequent in group B (16% versus 0%). The incidence of postoperative heartburn did not differ by group. There were no deaths. At 18 and 22 months, 92% and 90% of patients had relief of their dysphagia. This study suggests that RAHM is safer than LHM, because it decreases the incidence of esophageal perforation to 0%, even in patients who had previous treatment. At short-term follow-up, relief of dysphagia was equally achieved in both groups.

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Kari Thompson

University of California

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Yoav Mintz

Hebrew University of Jerusalem

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Alisa M. Coker

University of California

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