Faculty Bibliography

Although the prevalence of obesity has increased dramatically throughout the world during the last 25 yr, its long-term control remains poor. Currently, only gastrointestinal weight loss surgery, especially Roux-en-Y gastric bypass (RYGB), is associated with substantial and sustained weight loss and resolution or significant improvement of diabetes mellitus and other metabolic obesity-induced complications. Clinical observations and recent studies have suggested that RYGB induces its effects by changing the physiology of weight regulation. Understanding the underlying mechanisms of these profound and sustainable effects could facilitate the development of novel and less invasive treatments against obesity and its complications. To study the physiological mechanisms of RYGB, we have developed a mouse RYGB model that replicates the human operation. The aims of this study were to develop a roadmap for assessing energy expenditure (EE) in animal models of weight loss surgery and to examine the effects of RYGB on EE. We first measured EE by indirect calorimetry in groups of animals that underwent RYGB or a sham operation. Calorimetry data were analyzed using three different methods: normalization by total body mass, allometric scaling, and analysis of covariance modeling. RYGB in mice induced a significant increase in EE that was independent of the method used. An energy balance analysis was then performed, which also confirmed that RYGB-treated animals have higher energy maintenance needs. Finally, we determined the EE components that account for the observed increase in EE, and we found that resting EE and postprandial thermogenesis are the major contributors to this increase.

PURPOSE: Laparoscopic bowel injury is associated with significant morbidity and mortality when unrecognized. We assessed the incidence and outcomes of bowel injury in a contemporary cohort of patients, and reviewed the literature to examine the impact of experience with time on the incidence and consequences of bowel injury. MATERIALS AND METHODS: Between 2006 and 2009 we performed 1,073 laparoscopic surgeries on the upper urinary tract, adrenal gland and retroperitoneal lymph nodes. Patients incurring bowel injury were identified retrospectively. We reviewed complications and management. In a separate literature survey we identified 21 studies on laparoscopic bowel injury from 1993 to 2009. We analyzed etiology, incidence and management. RESULTS: Bowel injury occurred in 8 cases (0.75%), including 6 and 2 identified intraoperatively and postoperatively, respectively. Mechanisms included Veress needle and trocar placement, dissection and thermal injury. Intraoperative management included oversewing the injury, bowel resection and observation. No patient with intraoperatively recognized bowel injury sustained a postoperative adverse event. Patients with unrecognized injury presented in delayed fashion and required multiple procedures to manage the injury. No deaths occurred in this series. Urology series of bowel injury showed a combined 0.65% incidence in 14,447 laparoscopic procedures with 46.7% of injuries unrecognized at surgery. While the incidence of bowel injury has increased with time, the percent of unrecognized bowel injury has dramatically decreased from the early (70.4%) to the more recent (36.9%) laparoscopic era. CONCLUSIONS: The incidence of laparoscopic bowel injury has increased in the last 17 years. However, morbidity and mortality have decreased due to immediate recognition and repair.