George C Velmahos

Massachusetts General Hospital, Boston, Massachusetts, United States

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Publications (411)1077.96 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Intracavitary noncompressible hemorrhage remains a significant cause of preventable death on the battlefield and in the homeland. We previously demonstrated the hemostatic efficacy of an in situ self-expanding poly(urea)urethane foam in a severe, closed-cavity, hepatoportal exsanguination model in swine. We hypothesized that treatment with, and subsequent explantation of, foam would not adversely impact 28-day survival in swine.
    The Journal of Trauma and Acute Care Surgery 09/2014; 77(3 Suppl 2):S127-S133. · 2.35 Impact Factor
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    ABSTRACT: With the dramatic growth in the very old population and their concomitant heightened exposure to traumatic injury, the trauma burden among this patient population is estimated to be exponentially increasing.
    JAMA surgery. 08/2014;
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    ABSTRACT: The implementation of the Affordable Care Act stimulated interest in outcomes of patients in Massachusetts, a state mandating health insurance as of 2006. We sought to determine the impact of an insurance mandate on hospital use and outcomes among trauma intensive care unit (ICU) patients.
    The Journal of Trauma and Acute Care Surgery 08/2014; 77(2):298-303. · 2.35 Impact Factor
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    ABSTRACT: We sought to assess the independent effect of concomitant adhesions (CAs) on patient outcome in abdominal surgery.
    Journal of Surgical Research 07/2014; · 2.02 Impact Factor
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    ABSTRACT: Noncompressible abdominal bleeding is a significant cause of preventable death on the battlefield and in the civilian setting, with no effective therapies available at point of injury. We previously reported that a self-expanding polyurethane foam significantly improved survival in a lethal hepatoportal injury model of massive venous hemorrhage. In this study, we hypothesized that foam treatment could improve survival in a lethal iliac artery injury model in noncoagulopathic swine.
    The Journal of Trauma and Acute Care Surgery 07/2014; 77(1):73-77. · 2.35 Impact Factor
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    ABSTRACT: BACKGROUND: Failure to achieve primary fascial closure (PFC) after damage control laparotomy is costly and carries great morbidity. We hypothesized that time from the initial laparotomy to the first take-back operation would be predictive of successful PFC. METHODS: Trauma patients managed with open abdominal techniques after damage control laparotomy were prospectively followed at 14 Level 1 trauma centers during a 2-year period. Time to the first take-back was evaluated as a predictor of PFC using hierarchical multivariate logistic regression analysis. RESULTS: A total of 499 patients underwent damage control laparotomy and were included in this analysis. PFC was achieved in 327 (65.5%) patients. Median time to the first take-back operation was 36 hours (interquartile range 24-48). After we adjusted for patient demographics, resuscitation volumes, and operative characteristics, increasing time to the first take-back was associated with a decreased likelihood of PFC. Specifically, each hour delay in return to the operating room (24 hours after initial laparotomy) was associated with a 1.1% decrease in the odds of PFC (odds ratio 0.989; 95% confidence interval 0.978-0.999; P = .045). In addition, there was a trend towards increased intra-abdominal complications in patients returning after 48 hours (odds ratio 1.80; 95% confidence interval 1.00-3.25; P = .05). CONCLUSION: Data from this prospective, multicenter study demonstrate that delays in returning to the operating room after damage control laparotomy are associated with reductions in PFC. These findings suggest that emphasis should be placed on returning to the operating room within 24 hours after the initial laparotomy if possible (and no later than 48 hours).
    Surgery 06/2014; · 3.37 Impact Factor
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    ABSTRACT: An overproduction of corticosterone during severe sepsis results in increased apoptosis of immune cells, which may result in relative immunosuppression and an impaired ability to fight infections. We have previously demonstrated that administration of tubastatin A, a selective inhibitor of histone deacetylase-6 (HDAC6), improves survival in a lethal model of cecal ligation and puncture (CLP) in mice. The purpose of this study was to characterize the effects of this treatment on sepsis-induced stress responses and immune function.
    Surgery 06/2014; · 3.37 Impact Factor
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    ABSTRACT: The CIAOW study (Complicated intra-abdominal infections worldwid e observational study) is a multicenter observational study underwent in 68 medical institut ions worldwide during a six-month study period (October 2012-March 2013). The study included patient s older than 18 years undergoing surgery or interventional drainage to address complicated intra-abdominal infections (IAIs). 1898 patients with a mean age of 51.6 years (range 18-99) were enrolle d in the study. 777 patients (41%) were women and 1,121 (59%) were men. Among these patients, 1,645 (86.7%) were affected by community-acquired IAIs while the remaining 253 (13.3%) suffered from healthcare-associated infections. Intraperitoneal specimens were collected from 1,190 (62.7%) of the enrolled patients. 827 patients (43.6%) were affected by generalized peritonitis while 1071 (56.4%) suffered from localized peritonitis or abscesses. The overall mortality rate was 10.5% (199/1898). According to stepwise multivariate analysis (PR = 0.005 and PE =0.001), several criteria were found to be independent variables predictive of mortality, including patient age (OR = 1.1; 95%CI = 1.0-1.1; p < 0.0001), the presence of small bowel perforation (OR = 2.8; 95%CI = 1.5-5.3; p < 0.0001), a delayed initial intervention (a delay excee ding 24 hours) (OR = 1.8; 95%CI = 1.5-3.7; p < 0.0001), ICU admission (OR = 5.9; 95%CI = 3.6-9.5; p < 0.0001) and patient immunosuppression (OR = 3.8; 95%CI = 2.1-6.7; p < 0.0001).
    World Journal of Emergency Surgery 05/2014; 9(37). · 0.92 Impact Factor
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    ABSTRACT: Little evidence exists regarding the characteristics of intraoperative adverse events (iAEs).
    American journal of surgery. 05/2014;
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    ABSTRACT: Background: Sepsis has a profound impact on the inflammatory and hemostatic systems. In addition to systemic inflammation, it can produce disseminated intravascular coagulation, microvascular thrombosis, consumptive coagulopathy, and multiple organ failure. We have shown that treatment with suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor (HDACI), improves survival in a lethal model of cecal ligation and puncture (CLP) in mice. However, its effect on coagulation remains unknown. The goal of this study was to quantify the impact of SAHA treatment on coagulopathy in sepsis. Methods: C57BL/6J mice were subjected to CLP, and 1 hour later given intraperitoneally either SAHA dissolved in dimethyl sulfoxide (DMSO) or DMSO only. Sham-operated animals were handled in similar manner without CLP. Blood samples were collected by cardiac puncture and evaluated using the TEG® 5000 Thrombelastograph® Hemostasis Analyzer System. Results: Compared to the sham group, all animals subjected to CLP died within 72 hrs, and developed coagulopathy that manifested as prolonged initial fibrin formation and fibrin cross-linkage time, and decreased clot formation speed, platelet function and clot rigidity. SAHA treatment significantly improved survival and was also associated with improvement in fibrin cross-linkage, clot formation, as well as platelet function and clot rigidity, without a significant impact on the clot initiation parameters. Conclusions: SAHA treatment enhances survival and attenuates sepsis-associated coagulopathy by improving fibrin cross-linkage, rate of clot formation, platelet function and clot strength. HDACI may represent a novel therapeutic strategy for correcting sepsis-associated coagulopathy.
    Surgery. 05/2014;
  • New England Journal of Medicine 04/2014; 370(15):1441-51. · 51.66 Impact Factor
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    ABSTRACT: BACKGROUND: MALNUTRITION AND UNDERFEEDING ARE MAJOR CHALLENGES IN CARING FOR CRITICALLY ILL PATIENTS. OUR GOAL WAS TO CHARACTERIZE INTERRUPTIONS IN ENTERAL NUTRITION (EN) DELIVERY AND THEIR IMPACT ON CALORIC DEBT IN THE SURGICAL INTENSIVE CARE UNIT (ICU). MATERIALS AND METHODS: We performed a prospective, observational study of adults admitted to surgical ICUs at a Boston teaching hospital (March-December 2012). We categorized EN interruptions as "unavoidable" vs "avoidable" and compared caloric deficit between patients with ≥1 EN interruption (group 1) vs those without interruptions (group 2). Multivariable logistic regression was used to investigate the association of EN interruption with the risk of underfeeding. Poisson regression was used to investigate the association of EN interruption with length of stay (LOS) and mortality. Ninety-four patients comprised the analytic cohort. Twenty-six percent of interruptions were deemed "avoidable." Group 1 (n = 64) had a significantly higher mean daily and cumulative caloric deficit vs group 2 (n = 30). Patients in group 1 were at a 3-fold increased risk of being underfed (adjusted odds ratio, 2.89; 95% confidence interval [CI], 1.03-8.11), had a 30% higher risk of prolonged ICU LOS (adjusted incident risk ratio [IRR], 1.27; 95% CI, 1.14-1.42), and had a 50% higher risk of prolonged hospital LOS (adjusted IRR, 1.53; 95% CI, 1.41-1.67) vs group 2. In our cohort of critically ill surgical patients, EN interruption was frequent, largely "unavoidable," and associated with undesirable outcomes. Future efforts to optimize nutrition in the surgical ICU may benefit from considering strategies that maximize nutrient delivery before and after clinically appropriate EN interruptions.
    Journal of Parenteral and Enteral Nutrition 04/2014; · 2.49 Impact Factor
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    ABSTRACT: Platelet dysfunction following trauma has been identified as an independent predictor of mortality. We hypothesized that fresh frozen plasma (FFP) resuscitation would attenuate platelet dysfunction compared with 0.9% normal saline (NS). Twelve swine were subjected to multisystem trauma (traumatic brain injury, liver injury, rib fracture, and soft tissue injury) with hemorrhagic shock (40% of estimated blood volume). Animals were left in shock (mean arterial pressure, 30-35 mm Hg) for 2 hours followed by resuscitation with three times shed volume NS (n = 6) or one times volume FFP (n = 6) and monitored for 6 hours. Platelet function was assessed by adenosine diphosphate (ADP)-induced platelet aggregation at baseline, after 2 hours of shock following resuscitation, and 6 hours after resuscitation. Fibrinogen levels and markers of platelet activation (transforming growth factor β [TGF-β], sP-Selectin, and CD40L) as well as endothelial injury (intercellular adhesion molecule 1 [ICAM-1], vascular cell adhesion molecule 1 [VCAM-1]) were also assayed. Thromboelastography was used to measure clotting activity. ADP-induced platelet aggregation was significantly higher in the FFP group (46.3 U vs. 25.5 U, p < 0.01) following resuscitation. This was associated with higher fibrinogen levels (202 mg/dL vs. 80 mg/dL, p < 0.01) but lower endothelial activation (VCAM-1, 1.25 ng/mL vs. 3.87 ng/mL, p = 0.05). Other markers did not differ.After 6 hours of observation, ADP-induced platelet aggregation remained higher in the FFP group (53.8 U vs. 37.0 U, p = 0.03) as was fibrinogen levels (229 mg/dL vs. 153 mg/dL, p < 0.01). Endothelial activation was lower (ICAM-1, 21.0 ng/mL vs. 24.4 ng/mL, p = 0.05), whereas TGF-β levels were higher (2,138 pg/mL vs. 1,802 pg/mL, p = 0.03) in the FFP group. Other markers did not differ. Thromboelastography revealed increased clot strength in the FFP group at both postresuscitation time points. Resuscitation with FFP resulted in an immediate and sustained improvement in platelet function and clot strength compared with high-volume NS resuscitation. This was associated with an increase in fibrinogen levels and an attenuation of endothelial activation.
    The journal of trauma and acute care surgery. 04/2014; 76(4):998-1007.
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    ABSTRACT: There is currently no systematic approach to evaluating the severity of intraoperative adverse events (iAEs). A 3-phase project was designed to develop and validate a novel severity classification scheme for iAEs. Phase 1 created the severity classification using a modified Delphi process. Phase 2 measured the classification's internal consistency by calculating inter-rater reliability among 91 surgeons using standardized iAEs scenarios. Phase 3 measured the classification's construct validity by testing whether major iAEs (severity class ≥3) correlated with worse 30-day postoperative outcomes compared with minor iAEs (severity class <3). This was achieved by creating a matched database using American College of Surgeons NSQIP and administrative data, querying for iAEs using the Patient Safety Indicator #15 (Accidental Puncture/Laceration), and iAE confirmation by chart review. Phase 1 resulted in a 6-point severity classification scheme. Phase 2 revealed an inter-rater reliability of 0.882. Of 9,292 patients, phase 3 included 181 confirmed with iAEs. All preoperative/intraoperative variables, including demographics, comorbidities, type of surgery performed, and operative length, were similar between patients with minor (n = 110) vs major iAEs (n = 71). In multivariable logistic analysis, severe iAEs correlated with higher risks of any postoperative complication (odds ratio [OR] = 3.8; 95% CI, 1.9-7.4; p < 0.001), surgical site infections (OR = 3.7; 95% CI, 1.7-8.2; p = 0.001), systemic sepsis (OR = 6.0; 95% CI, 2.1-17.2; p = 0.001), failure to wean off the ventilator (OR = 3.2; 95% CI, 1.2-8.9; p = 0.022), and postoperative length of stay ≥7 days (OR = 3.0; 95% CI, 1.5-5.9; p = 0.002). Thirty-day mortalities were similar (4.5% vs 7.1%; p = 0.46). We propose a novel iAE severity classification system with high internal consistency and solid construct validity. Our classification scheme might prove essential for benchmarking quality of intraoperative care across hospitals and/or individual surgeons.
    Journal of the American College of Surgeons 02/2014; · 4.50 Impact Factor
  • George C Velmahos
    Surgical Clinics of North America 02/2014; 94(1):xiii-xv. · 2.02 Impact Factor
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    ABSTRACT: Of the patients with a Clostridium difficile infection, 2% to 8% will progress to fulminant C. difficile colitis (fCDC), which carries high morbidity and mortality. No system exists to rapidly identify patients at risk for developing fCDC and possibly in need of surgical intervention. Our aim was to design a simple and accurate risk scoring system (RSS) for daily clinical practice. We prospectively enrolled all patients diagnosed with a C. difficile infection and compared patients with and without fCDC. An expert panel, combined with data derived from previous studies, identified four risk factors, and a multivariable logistic regression model was performed to determine their effect in predicting fCDC. The RSS was created based on the predictive power of each factor, and calibration, discrimination, and test characteristics were subsequently determined. In addition, the RSS was compared with a previously proposed severity scoring system. A total of 746 patients diagnosed with C. difficile infection were enrolled between November 2010 and October 2012. Based on the log (odds ratio) of each risk factor, age greater than 70 years was assigned 2 points, white blood cell count equal to or greater than 20,000/μL or equal to or less than 2,000/μL was assigned 1 point, cardiorespiratory failure was assigned 7 points, and diffuse abdominal tenderness on physical examination was assigned 6 points. With the use of this system, the discriminatory value of the RSS (c statistic) was 0.98 (95% confidence interval, 0.96-1).The Hosmer-Lemeshow goodness-of-fit test showed a p value of 0.78, and the Brier score was 0.019. A value of 6 points was determined to be the threshold for reliably dividing low-risk ( <6) from high-risk (≥6) patients. The RSS is a valid and reliable tool to identify at the bedside patients who are at risk for developing fCDC. External validation is needed before widespread implementation. Prognostic study, level II.
    The journal of trauma and acute care surgery. 02/2014; 76(2):424-30.
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    ABSTRACT: Clostridium difficile is the most common cause of nosocomial diarrhea, affecting up to 10% of hospitalized patients. Preliminary studies suggest an association between vitamin D status and C difficile infections (CDIs). Our goal was to investigate whether serum 25-hydroxyvitamin D (25(OH)D) levels are associated with CDI severity. Methods: We prospectively enrolled patients diagnosed with CDI and divided them into 2 severity groups: group A (positive toxin A/B enzyme immunoassay only) and group B (positive toxin A/B enzyme immunoassay with abdominal computed tomography scan findings consistent with colitis). Serum 25(OH)D levels (25(OH)D3, 25(OH)D2, and total 25(OH)D) were measured on all patients after diagnosis of CDI. We performed multivariable logistic regression analyses to investigate the association between 25(OH)D levels and CDI severity, while adjusting for age, Deyo-Charlson Comorbidity Index, recent hospitalization, and vitamin D supplementation. Results: One hundred patients were enrolled between July 2011 and February 2013. The mean (standard deviation) cohort age and Deyo-Charlson Comorbidity Index were 62 (19) years and 4 (3), respectively; 54% of patients were male. Mean serum total 25(OH)D level was 22 (10) ng/mL. Mean 25(OH)D3 level was significantly higher in group A (n = 71) than in group B (n = 29): 21 (1) vs 15 (2) ng/mL, respectively (P = .005). There was no observed difference in mean 25(OH)D2 levels and total 25(OH)D levels between the 2 groups. Multivariable logistic regression analysis demonstrated an association between 25(OH)D3 levels and CDI severity (adjusted odds ratio, 0.92; 95% confidence interval, 0.87-0.98). Conclusions: We found a significant inverse association between 25(OH)D3 levels and CDI severity. Further studies are needed to determine whether vitamin D supplementation can improve outcomes in patients with CDI.
    Journal of Parenteral and Enteral Nutrition 01/2014; · 2.49 Impact Factor
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    ABSTRACT: Background Failure to achieve primary fascial closure (PFC) after damage control laparotomy is costly and carries great morbidity. We hypothesized that time from the initial laparotomy to the first take-back operation would be predictive of successful PFC. Methods Trauma patients managed with open abdominal techniques after damage control laparotomy were prospectively followed at 14 Level 1 trauma centers during a 2-year period. Time to the first take-back was evaluated as a predictor of PFC using hierarchical multivariate logistic regression analysis. Results A total of 499 patients underwent damage control laparotomy and were included in this analysis. PFC was achieved in 327 (65.5%) patients. Median time to the first take-back operation was 36 hours (interquartile range 24–48). After we adjusted for patient demographics, resuscitation volumes, and operative characteristics, increasing time to the first take-back was associated with a decreased likelihood of PFC. Specifically, each hour delay in return to the operating room (24 hours after initial laparotomy) was associated with a 1.1% decrease in the odds of PFC (odds ratio 0.989; 95% confidence interval 0.978–0.999; P = .045). In addition, there was a trend towards increased intra-abdominal complications in patients returning after 48 hours (odds ratio 1.80; 95% confidence interval 1.00–3.25; P = .05). Conclusion Data from this prospective, multicenter study demonstrate that delays in returning to the operating room after damage control laparotomy are associated with reductions in PFC. These findings suggest that emphasis should be placed on returning to the operating room within 24 hours after the initial laparotomy if possible (and no later than 48 hours).
    Surgery 01/2014; · 3.37 Impact Factor
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    ABSTRACT: Traumatic brain injury (TBI) and hemorrhagic shock (HS) can be associated with coagulopathy and inflammation, but the mechanisms are poorly understood. We hypothesized that a combination of TBI and HS would disturb coagulation, damage the endothelium, and activate inflammatory and complement systems. A total of 33 swine were allocated to either TBI + HS (n = 27, TBI and volume-controlled 40% blood loss) or controls (n = 6, anesthesia and instrumentation). TBI + HS animals were left hypotensive (mean arterial pressure, 30-35 mm Hg) for 2 hours. Blood samples were drawn at baseline, 3 minutes and 15 minutes after injury, as well as following 2 hours of hypotension. Markers of coagulation, anticoagulation, endothelial activation/glycocalyx shedding, inflammation, complement, and sympathoadrenal function were measured. The TBI + HS group demonstrated an immediate (3 minutes after injury) activation of coagulation (prothrombin fragment 1 + 2, 289 ng/mL vs. 232 ng/mL, p = 0.03) and complement (C5a, 2.83 ng/mL vs. 2.05 ng/mL, p = 0.05). Shedding of the endothelial glycocalyx (syndecan 1) was evident 15 minutes after injury (851.0 ng/ml vs. 715.5 ng/ml, p = 0.03) while inflammation (tumor necrosis factor α [TNF-α], 81.1 pg/mL vs. 50.8 pg/mL, p = 0.03) and activation of the protein C system (activated protein C, 56.7 ng/mL vs. 26.1 ng/mL, p = 0.01) were evident following the 2-hour hypotension phase. The combination of TBI and shock results in an immediate activation of coagulation and complement systems with subsequent endothelial shedding, protein C activation, and inflammation.
    The journal of trauma and acute care surgery. 01/2014; 76(1):12-20.
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    ABSTRACT: Standard teaching is that patients with pneumoperitoneum on plain X-ray and clinical signs of abdominal pathology should undergo urgent surgery. It is unknown if abdominal computed tomography (CT) provides additional useful information in this scenario. The aim of this study is to determine whether or not CT scanning after identification of pneumoperitoneum on plain X-ray changes clinical management or outcomes. Retrospective study carried out over 4 years at a tertiary care academic medical center. All patients in our acute care surgery database with pneumoperitoneum on plain X-ray were included. Patients who underwent subsequent CT scanning (CT group) were compared with patients who did not (non-CT group). The Wilcoxon rank-sum test, t-test and Fisher's exact test were used as appropriate to compare the groups. There were 25 patients in the non-CT group and 18 patients in the CT group. There were no differences between the groups at presentation. All patients in the non-CT group underwent surgery, compared with 83% (n = 15) of patients in the CT group (P = 0.066). 16 patients in the non-CT and 11 patients in the CT group presented with peritonitis and all underwent surgery regardless of group. For patients undergoing surgery, there were no differences in outcomes between the groups. After X-ray, patients undergoing CT required 328.0 min to arrive in the operating room compared with 136.0 min in the non-CT group (P = 0.007). In patients with pneumoperitoneum on X-ray and peritonitis on physical exam, CT delays surgery without providing any measurable benefit.
    Journal of Emergencies Trauma and Shock 01/2014; 7(1):3-8.

Publication Stats

7k Citations
1,077.96 Total Impact Points

Institutions

  • 2006–2014
    • Massachusetts General Hospital
      • • Department of Surgery
      • • Division of Trauma, Emergency Surgery and Surgical Critical Care
      Boston, Massachusetts, United States
    • Harvard Medical School
      • Department of Surgery
      Boston, Massachusetts, United States
  • 2012
    • University of Massachusetts Medical School
      • Department of Surgery
      Worcester, MA, United States
  • 1995–2012
    • University of Southern California
      • Department of Surgery
      Los Angeles, CA, United States
  • 2011
    • Marlborough Hospital
      Marlborough, Massachusetts, United States
  • 2006–2008
    • Uniformed Services University of the Health Sciences
      • Department of Surgery
      Bethesda, MD, United States
  • 1996–2008
    • University of California, Los Angeles
      • Department of Surgery
      Los Angeles, CA, United States
  • 2005
    • Partners HealthCare
      Boston, Massachusetts, United States
  • 2004
    • Oregon Health and Science University
      • Department of Surgery
      Portland, OR, United States
  • 2002
    • California State University, Sacramento
      Sacramento, California, United States
  • 2000
    • Keck School of Medicine USC
      Los Angeles, California, United States
  • 1999
    • Santa Barbara Cottage Hospital
      Santa Barbara, California, United States
  • 1994–1998
    • Chris Hani Baragwanath Hospital
      Johannesburg, Gauteng, South Africa
  • 1993–1998
    • University of the Witwatersrand
      • Department of Surgery
      Johannesburg, Gauteng, South Africa