Kevin M Reavis

University of California, Irvine, Irvine, CA, United States

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Publications (57)229.83 Total impact

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    ABSTRACT: BACKGROUND: Acute respiratory failure (ARF) can be a life-threatening postoperative complication after bariatric surgery and is defined as the presence of acute respiratory distress or pulmonary insufficiency. We sought to identify predictors of ARF in patients who underwent bariatric surgery. METHODS: Using the Nationwide Inpatient Sample database, from 2006 to 2008, the clinical data from morbidly obese patients who underwent bariatric surgery were examined. Multivariate regression analysis was performed to identify the independent factors predictive of ARF. The factors examined included patient characteristics, co-morbidities, payer type, teaching status of hospital, surgical techniques (laparoscopic versus open), and type of bariatric operation (gastric bypass versus nongastric bypass). RESULTS: A total of 304,515 patients underwent bariatric surgery during the 3-year period. The overall ARF rate was 1.35%. The greatest rate of ARF (4.10%) was observed after open gastric bypass surgery. The ARF rate was lower after laparoscopic than after the open surgical technique (.94% versus 3.87%, respectively; P < .01) and after nongastric bypass versus gastric bypass (.82% versus 1.54%, respectively; P < .01). Using multivariate regression analysis, congestive heart failure (adjusted odds ratio [AOR] 5.1), open surgery (AOR 3.3), chronic renal failure (AOR 2.9), gastric bypass (AOR 2.5), peripheral vascular disease (AOR 2.4), male gender (AOR 1.9), age >50 years (AOR 1.8), Medicare payer (AOR 1.8), alcohol abuse (AOR 1.8), chronic lung disease (AOR 1.6), diabetes mellitus (AOR 1.2), and smoking (AOR 1.1) were factors associated with greater rates of ARF. Compared with patients without ARF, patients with ARF had significantly greater in-hospital mortality (5.69% versus .04%, P < .01). CONCLUSION: We identified multiple risk factors that have an effect on the development of acute respiratory failure after bariatric surgery. Surgeons should consider these factors in surgical decision-making and inform patients of their risk of this potentially life-threatening complication.
    Surgery for Obesity and Related Diseases 03/2012; · 4.12 Impact Factor
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    ABSTRACT: Strategic laparoscopic surgery for improved cosmesis (SLIC) is a less invasive surgical approach than conventional laparoscopic surgery. The aim of this study was to examine the feasibility and safety of SLIC for general and bariatric surgical operations. Additionally, we compared the outcomes of laparoscopic sleeve gastrectomy with those performed by the SLIC technique. In an academic medical center, from April 2008 to December 2010, 127 patients underwent SLIC procedures: 38 SLIC cholecystectomy, 56 SLIC gastric banding, 26 SLIC sleeve gastrectomy, 1 SLIC gastrojejunostomy, and 6 SLIC appendectomy. SLIC sleeve gastrectomy was initially performed through a single 4.0-cm supraumbilical incision with extraction of the gastric specimen through the same incision. The technique evolved to laparoscopic incisions that were all placed within the umbilicus and suprapubic region. There were no 30-day or in-hospital mortalities or 30-day re-admissions or re-operations. For SLIC cholecystectomy, gastric banding, appendectomy, and gastrojejunostomy, conversion to conventional laparoscopy occurred in 5.3%, 5.4%, 0%, and 0%, respectively; there were no major or minor postoperative complications. For SLIC sleeve gastrectomy, there were no significant differences in mean operative time and length of hospital stay compared with laparoscopic sleeve gastrectomy; 1 (3.8%) of 26 SLIC patients required conversion to five-port laparoscopy. There were no major complications. Minor complications occurred in 7.7% in the SLIC sleeve group versus 8.3% in the laparoscopic sleeve group. SLIC in general and bariatric operations is technically feasible, safe, and associated with a low rate of conversion to conventional laparoscopy. Compared with laparoscopic sleeve gastrectomy, SLIC sleeve gastrectomy can be performed without a prolonged operative time with comparable perioperative outcomes.
    Journal of Laparoendoscopic & Advanced Surgical Techniques 03/2012; 22(4):355-61. · 1.07 Impact Factor
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    ABSTRACT: BACKGROUND: An obesity surgery mortality risk score derived from a single clinical series can be used to stratify the mortality risk of patients undergoing gastric bypass. However, such a scoring system does not take into account 2 important factors in contemporary bariatric surgery-increased use of the laparoscopic approach and laparoscopic adjustable gastric banding. The present study analyzed the preoperative factors that might predict in-hospital mortality after bariatric surgery using data from academic medical centers and proposes a classification system for predicting mortality. METHODS: Using the "International Classification of Diseases, 9th revision," diagnosis and procedural codes, the data for all patients who underwent bariatric surgery for the treatment of morbid obesity from 2002 to 2009 were obtained from the University HealthSystem Consortium database. The limitations of this database included the lack of the body mass index and the underestimation of some co-morbidities, such as sleep apnea. Multiple regression analyses were performed to determine the factors predictive of greater in-hospital mortality. The factors examined included race, gender, age, co-morbidities, surgical technique (laparoscopic versus open), bariatric operation (gastric bypass versus nongastric bypass), and payer type. A scoring system was devised by assigning 1 point for each major factor (those with an adjusted odds ratio [AOR] of ≥2.0) and .5 point for each minor factor (those with an AOR <2.0). Using contemporary data from 2007 to 2009, the in-hospital mortality was analyzed according to the classification: class I, 0-0.5 point; class II, 1.0-1.5 points; class III, 2.0-3.0 points; and class IV, ≥ 3.5 points. RESULTS: During the 8-year period, 105,287 patients underwent bariatric surgery. The operations included laparoscopic gastric bypass (45%), open gastric bypass (41%), and laparoscopic gastric banding or gastroplasty (14%). The overall in-hospital mortality rate was .17%. The number of deaths per 1000 bariatric operations decreased from 4.0 in 2002 to .6 in 2009. Using regression analyses, the factors predictive of greater in-hospital mortality were male gender (AOR 3.2), gastric bypass procedure (AOR 5.8), open surgical technique (AOR 4.8), Medicare payer (AOR 3.0), diabetes (AOR 1.6), and age >60 years (AOR 1.9). The mortality rate was .10% for class I patients, .15% for class II, .33% for class III, and .70% for class IV (P < .05 among all classes). CONCLUSION: Within the context of academic centers, the mortality after bariatric surgery has decreased substantially since 2002, with an increase in the use of the laparoscopic technique and laparoscopic gastric banding. A bariatric mortality risk classification system was developed to stratify mortality, given the limits of this database, which does not include the body mass index and underestimates the incidence of sleep apnea. It might be useful to aid surgeons in surgical decision-making, to inform patients of their risks, and for quality improvement reporting purposes.
    Surgery for Obesity and Related Diseases 12/2011; · 4.12 Impact Factor
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    ABSTRACT: Esophagectomy can be associated with significant morbidity such as leaks and strictures. Preoperative gastric ischemic conditioning is a concept aimed at inducing an ischemic insult to the gastric fundus and cardia prior to esophagectomy, thus leading to improvement of gastric perfusion. This retrospective study compared outcome data from 81 patients who underwent esophagectomy after laparoscopic gastric ischemic conditioning with that from 71 patients who underwent esophagectomy without conditioning. Gastric ischemic conditioning consisted of laparoscopic division of the left gastric vessels ± the short gastric vessels. The time interval from gastric ischemic conditioning to esophagectomy ranged from 2 to 75 days. Main outcome measures included demographics, mean time interval between staging and esophagectomy, and the rate of leaks and strictures following esophagectomy. The two groups were comparable with respect to gender and age. In the gastric ischemic conditioning procedures, there were no conversions; the mean operative time was 57 ± 15 min, the mean length of hospital stay was 1.0 ± 1.1 days, and the rate of postoperative complications was 3.7%. The mean time interval between gastric ischemic conditioning and esophagectomy was 6.0 ± 5.4 days. There were no significant differences in the leak rate (11.1% for conditioning vs. 8.5% without conditioning) or stricture rate (29.6% for conditioning vs. 25.3% without conditioning) between the two groups. Laparoscopic gastric ischemic conditioning is feasible and safe. However, the use of gastric ischemic conditioning in this study did not alter the clinical rate of postoperative leaks and strictures.
    Surgical Endoscopy 12/2011; 26(6):1637-41. · 3.43 Impact Factor
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    ABSTRACT: Bariatric surgery in the adolescent continues to be a controversial topic. This study compared the utilization and perioperative outcomes of adolescent bariatric surgery performed at academic centers from 2002 to 2006 versus 2007 to 2009. We obtained data from the University HealthSystem Consortium for all adolescent patients (ages 12-18 years) who underwent bariatric surgery for the treatment of morbid obesity between 2002 and 2009. Outcomes including type of procedure, characteristics, length of stay, 30-day readmission, morbidity, and in-hospital mortality were compared between the two time periods. From 2007 to 2009, 340 adolescents underwent bariatric surgery at 63 academic hospitals. The mean number of adolescent bariatric procedures performed/year increased from 61.8 in 2002 to 2006 to 113.3 procedures/year in 2007 to 2009. There was an increase in utilization of laparoscopic gastric banding from 29 per cent to 50 per cent with a decrease in utilization of gastric bypass from 62 per cent to 48 per cent, respectively. For 2007 to 2009, the overall morbidity was 2.9 per cent with a 30-day readmission of 1.5 per cent and an in-hospital mortality of 0 per cent. Within the context of academic medical centers, adolescent bariatric surgery is associated with low morbidity and no mortality. Compared with 2002 to 2006, there has been an increase in the number of adolescent bariatric operations with increase in utilization of the laparoscopic gastric banding.
    The American surgeon 11/2011; 77(11):1510-4. · 0.92 Impact Factor
  • Kevin M Reavis
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    ABSTRACT: Obesity and gastroesophageal reflux disease (GERD) are common chronic illnesses. They often coexist and need to be treated concomitantly. Fundoplication may be effective for the short-term control of GERD in the obese patient; however, this procedure does not induce weight loss or treat the comorbid conditions related to obesity. Roux-en-Y gastric bypass is a highly effective treatment of GERD, obesity, and the associated comorbidities. Surgeons who are not comfortable with a bariatric surgical procedure in these patients should either complete appropriate advanced training in bariatric surgery or refer those patients to a qualified surgeon who can offer these options.
    Thoracic Surgery Clinics 11/2011; 21(4):489-98.
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    ABSTRACT: Transoral incisionless fundoplication is a new treatment for patients with gastroesophageal reflux disease. We present our initial experience with 10 patients undergoing this procedure with varying past surgical histories. All procedures were performed under general nasotracheal anesthesia. RAND-36 and Visual Analog Scale symptom scores were collected at pre and postoperative appointments for a mean of 9.2 months. The mean procedure time was 68 minutes. There were no intraoperative or postoperative complications. Patients with prior pancreaticoduodenectomy had observed reduced working space due to prior distal gastrectomy and required additional insufflation due to no pyloric resistance to insufflation of the small bowel. The patient with prior fundoplication required additional time and force for fastener penetration of the resultant scar from the partially disrupted fundoplication. All patients were discharged within 23 hours of the procedure. Throughout the follow-up period, patients reported gradual changes in medication requirements and symptom scores. There were no late complications. Transoral incisionless fundoplication is technically safe in well-selected patients including those with prior esophageal and gastric surgery.
    The American surgeon 10/2011; 77(10):1386-9. · 0.92 Impact Factor
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    ABSTRACT: Venous thromboembolism (VTE) is a significant cause of morbidity and mortality in bariatric surgery. The aim of this study was to evaluate the effect of patient characteristics, payer type, comorbidities, and surgical techniques on development of VTE in bariatric surgery. Using the National Inpatient Sample (NIS) database from 2006 to 2008, clinical data of 304,515 morbidly obese patients who underwent bariatric surgery were examined. Multiple regression analysis was performed to identify factors predictive of VTE. The overall rate of in-hospital VTE was 0.17 per cent, with the highest rate of VTE observed in open gastric bypass (0.45%). The VTE rate was significantly lower in laparoscopic compared with open gastric bypass (0.13% vs 0.45%, respectively, P < 0.01) and in nongastric bypass compared with gastric bypass procedures (0.06% vs 0.21%, respectively, P < 0.01). Alcohol abuse [odds ratio (OR): 8.7], open operation (OR: 2.5), gastric bypass procedures (OR: 2.4), renal failure (OR: 2.3), congestive heart failure (OR: 2.0), male gender (OR: 1.5), and chronic lung disease (OR: 1.4) were associated with a higher rate of VTE. This study identified several significant risk factors for development of VTE in bariatric surgery. To minimize the risk of VTE, surgeons may consider these factors in selection of appropriate prophylaxis and bariatric surgical options.
    The American surgeon 10/2011; 77(10):1403-6. · 0.92 Impact Factor
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    ABSTRACT: Gastrointestinal leak is a dreaded complication after esophagectomy. Conventional treatments for leak include conservative therapy, surgical reoperation, and even complete gastrointestinal (GI) diversion. The aim of this study was to evaluate the impact of endoluminal stenting in the management of esophagogastric leak after esophagectomy. Data on 18 (11.3%) of 160 patients who developed postoperative leaks after minimally invasive esophagectomy were reviewed. Indications for esophagectomy included carcinoma (n = 14), Barrett's with high-grade dysplasia (n = 3), and benign stricture (n = 1). Neoadjuvant therapy was used in 57.1% of patients with carcinoma. The first nine patients underwent conventional treatments for leak whereas the latter nine patients underwent endoscopic esophageal covered stenting as primary therapy. There were 5 cervical and 13 intrathoracic anastomotic leaks. Main outcome measures included patient characteristics, types of treatment, length of hospital stay, morbidity, and mortality. Subjects were 16 males and 2 females with a mean age of 66 years. In the conventional treatment group, leaks were treated with neck drainage (n = 4), GI diversion (n = 2), and thoracoscopic drainage with or without repair or T-tube placement (n = 3). In the endoscopy group, all leaks were treated with endoscopic covered stenting with or without percutaneous drainage (n = 9). Control of leaks occurred in 89% of patients in the conventional treatment group vs. 100% of patients in the endoscopic stenting group. Three patients in the conventional treatment group (33%) required esophageal diversion compared to none of the patients in the endoscopy group. The 60-day or in-hospital mortality was 0% for both groups. In our clinical practice, there has been a shift in the management of esophagogastric anastomotic leaks to nonsurgical therapy using endoscopic esophageal covered stenting. Endoluminal stenting is a safe and effective alternative in the management of GI leaks.
    Journal of Gastrointestinal Surgery 09/2011; 15(11):1952-60. · 2.36 Impact Factor
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    ABSTRACT: Patient characteristics and comorbidities, payer type, and operative technique (laparoscopic vs open) predict the risk of gastrointestinal (GI) tract leak in patients with morbid obesity undergoing gastric bypass. Retrospective database analysis. Nationwide Inpatient Sample. Between January 1, 2006, and December 31, 2008, patients who underwent open or laparoscopic gastric bypass to treat morbid obesity. Factors predictive of GI tract leak using multivariate regression analyses. A total 226,452 patients underwent laparoscopic (81.2%) or open (18.8%) gastric bypass during the 3-year period. Most patients were female (80.5%) and of white race/ethnicity (73.6%). The mean age of patients was 43.6 years; 30.0% of patients were older than 50 years. The overall prevalence of in-hospital GI tract leak was 0.7%. The GI tract leak rate was significantly lower in laparoscopic compared with open gastric bypass (0.3% vs 2.0%, P < .01). Using multivariate regression analysis, factors associated with higher risk of GI tract leak were open gastric bypass (adjusted odds ratio [aOR], 4.85), congestive heart failure (aOR, 3.04), chronic renal failure (aOR, 2.38), age older than 50 years (aOR, 1.82), Medicare payer (aOR, 1.54), male sex (aOR, 1.50), and chronic lung disease (aOR, 1.21). The GI tract leak rate was unaffected by race/ethnicity, hypertension, diabetes mellitus, sleep apnea, hyperlipidemia, liver disease, peripheral vascular disease, or smoking. We identified multiple factors associated with the higher risk of GI tract leak after gastric bypass. Surgeons should use this knowledge to counsel patients and possibly alter operative plans in high-risk patients to minimize this risk.
    Archives of surgery (Chicago, Ill.: 1960) 09/2011; 146(9):1048-51. · 4.32 Impact Factor
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    ABSTRACT: Understanding predictors of mortality in bariatric surgery enables surgeons to use these factors for analysis of risk-adjusted mortality and aids in the surgical decision making and informed consent process. To evaluate the effect of patient characteristics (age, gender, race, and payer type), preoperative comorbidities, and operative technique (laparoscopic versus open, gastric bypass versus gastric band) on mortality in patients who underwent bariatric operations. Using the National Inpatient Sample database, clinical data of patients with morbid obesity who underwent bariatric surgery from 2006 to 2008 were examined. Multivariate logistic regression analyses were performed to identify independent predictors of in-hospital mortality. A total 304,515 patients underwent bariatric surgery over the 3-year period. The majority of patients were female (80%) and Caucasian (74%). Their mean age was 44 years and 31.6% were >50 years old. The most common payer type was private (73.5%). Laparoscopic approach was utilized in 86.2% of cases. The overall in-hospital mortality was 0.12%. Using multivariate regression analysis, male gender (adjusted odds ratio [AOR], 1.7), age >50 years (AOR, 3.8), congestive heart failure (AOR, 9.5), peripheral vascular disease (AOR, 7.4), chronic renal failure (AOR, 2.7), open procedure (AOR, 5.5), and gastric bypass operation (AOR, 1.6) were factors associated with greater mortality. Ethnicity, hypertension, diabetes, liver disease, chronic lung disease, sleep apnea, alcohol abuse, and payer type had no association with mortality in this study. Modifiable risk factors predictive of mortality include open surgery and gastric bypass procedure; nonmodifiable risk factors include older age, male gender, and a history of congestive heart failure, peripheral vascular disease, and chronic renal failure. Surgeons should consider these factors in selection of patients to undergo bariatric operations, providing informed consent, and selection of the procedural type.
    Surgery 08/2011; 150(2):347-51. · 3.37 Impact Factor
  • Hubert D Kim, Kevin M Reavis, Ninh T Nguyen
    Surgery for Obesity and Related Diseases 06/2011; 8(5):e59. · 4.12 Impact Factor
  • Surgery for Obesity and Related Diseases 05/2011; 7(3):342. · 4.12 Impact Factor
  • Journal of Surgical Research 02/2011; 165(2):175. · 2.02 Impact Factor
  • Gastroenterology 01/2011; 140(5). · 12.82 Impact Factor
  • Hubert Kim, Ninh T. Nguyen, Kevin M. Reavis
    Gastroenterology 01/2011; 140(5). · 12.82 Impact Factor
  • Hubert Kim, Kevin M. Reavis, Ninh T. Nguyen
    Gastroenterology 01/2011; 140(5). · 12.82 Impact Factor
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    ABSTRACT: Minimally invasive surgery continues to revolutionize surgical standards with trends toward further minimalization and improved cosmesis. Approaches such as laparoendoscopic single-site surgery (LESS) and natural orifice translumenal endoscopic surgery (NOTES) have thus emerged. The authors devised an alternative method for a more efficient approach to minimally invasive surgery called no visible scar (NVIS). This study describes NVIS and its ability to provide operative capacity and outcomes similar to other minimal access techniques, but with improved cosmesis and possibly decreased associated complications. This is a retrospective analysis of patients undergoing colectomy between June 2009 and March 2010 to evaluate our outcomes with the NVIS technique (surgical approach via a 4-5 cm suprapubic site for inserting trocars/multiport and specimen extraction, with a 5-mm umbilical incision for a single trocar). Outcome measures included intraoperative complications, postoperative morbidity, and cosmetic outcome. Ten patients with a mean age of 60.3 years underwent NVIS colectomy. The average operating time was 161.3 minutes with a mean blood loss of 56.5 mL. There were no conversions to open surgery. One patient required additional trocar placement. No perioperative complications were encountered. On follow-up, no wound complications were noted and all patients appeared satisfied with their cosmetic outcome. One patient was readmitted for a low-grade fever, but the NVIS technique was not identified as a contributor. NVIS is a safe and feasible minimal access alternative, which improves cosmesis and may decrease complications associated with other minimally invasive techniques. Further analysis in a larger patient population is warranted to support our findings.
    Surgical Innovation 12/2010; 18(1):79-85. · 1.54 Impact Factor
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    ABSTRACT: Pyloroplasty is performed during esophagectomy to avoid delayed gastric emptying. However, studies have shown that gastric function is minimally impaired even without a pyloroplasty when a gastric tube rather than the whole stomach is used for reconstruction. The aim of this study was to evaluate outcomes of minimally invasive esophagectomy without performance of a pyloroplasty. We performed a retrospective review of 145 patients who underwent a minimally invasive esophagectomy. The 30-day mortality was 2.1 per cent with an in-hospital mortality of 3.4 per cent. Of the 140 patients with more than 90 days follow-up, 31 patients had a pyloroplasty and 109 patients did not. One (3.2%) of 31 patients with pyloroplasty versus six (5.5%) of 109 patients without pyloroplasty developed delayed gastric emptying. There was no significant difference in the leak rate between the two groups (9.7% vs. 9.6%, respectively). Total operative time was significantly shorter in the group without pyloroplasty (360 vs. 222 minutes with a pyloroplasty, P < 0.01). Patients with delayed gastric emptying responded well to endoscopic pyloric dilation or Botox injection. The routine performance of a pyloroplasty during minimally invasive esophagectomy can be safely omitted with a reduction in operative time and minimal adverse effects on postoperative gastric function.
    The American surgeon 10/2010; 76(10):1135-8. · 0.92 Impact Factor
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    ABSTRACT: The optimal method for closing gastrotomies after transgastric instrumentation has yet to be determined. To compare gastrotomy closure with endoscopically delivered bioabsorbable plugs with no closure. Prospective, controlled study. Animal laboratory. Twenty-three dogs undergoing endoscopic transgastric peritoneoscopy between July and August 2007. Endoscopic anterior wall gastrotomies were performed with balloon dilation to allow passage of the endoscope into the peritoneal cavity. The plug group (n = 12) underwent endoscopic placement of a 4 x 6-cm bioabsorbable mesh plug in the perforation, whereas the no-treatment group (n = 11) did not. Animals underwent necropsy 2 weeks after the procedure. Complications related to gastrotomy closure, gastric burst pressures, relationship of burst perforation to gastrotomy, and the degree of adhesions and inflammation at the gastrotomy site. After the gastrotomy, all dogs survived without any complications. At necropsy, burst pressures were 77 +/- 11 mm Hg and 76 +/- 15 mm Hg (P = .9) in the plug group and no-treatment group, respectively. Perforations occurred at the site of the gastrotomy in 2 of 12 animals in the plug group and in none of the 11 dogs in the no-treatment group (P = .5). Finally, there were minimal adhesions in all dogs (11/11) in the no-treatment group and minimal adhesions in 3 and moderate adhesions or inflammatory masses in 9 of the 12 animals in the plug group (P = .004). Small number of subjects, animal model, no randomization. Gastrotomy trauma during short peritoneoscopy may not be applicable to longer procedures. After endoscopic gastrotomy, animals that were left untreated did not show any clinical ill effects and demonstrated adequate healing, with fewer adhesions and less inflammation compared with those treated with a bioabsorbable plug.
    Gastrointestinal endoscopy 05/2010; 71(6):1013-7. · 6.71 Impact Factor

Publication Stats

840 Citations
229.83 Total Impact Points


  • 2009–2012
    • University of California, Irvine
      • Department of Surgery
      Irvine, CA, United States
  • 2008–2010
    • The Ohio State University
      • Department of Surgery
      Columbus, OH, United States
  • 2005–2006
    • Oregon Health and Science University
      • Department of Surgery
      Portland, OR, United States
  • 2004–2006
    • Portland VA Medical Center
      Portland, Oregon, United States