Matthew I. Goldblatt

Decreased gallbladder response in leptin-deficient obese mice

Obesity is a major risk factor for gallstone formation, but the pathogenesis of this phenomenon remains unclear. Human data on gallbladder emptying are conflicting, and no animal data exist on the effect of obesity on gallbladder motility. Leptin, a hormone produced by adipocytes, is known to have central effects on neuropeptide Y and cholecystokinin, but the influence of leptin on the biliary effects of these hormones is unknown. Therefore we tested the hypothesis that leptin-deficient C57BL/6J-lepob obese mice would have decreased gallbladder responses to excitatory stimuli. Twelve-week-old lean control (C57BL/6J) (n = 22) and C57BL/6J-lepob obese (n = 20) female mice were fed a nonlithogenic diet. The mice were fasted overnight and underwent cholecystectomy. Whole gallbladders were placed in 3 ml muscle baths. After optimal length was determined with acetylcholine (10-5 mol/L, responses to increasing doses of neuropeptide Y (10-8 to 10-6 mol/L) and cholecystokinin-8 (10-10 to 10-7 mol/L) were measured. Student’s t test and two-way analysis of variance were used where appropriate. Results were expressed as Newtons per cross-sectional area. The lean control mice had significantly greater excitatory responses to acetylcholine than the obese mice (0.37 ± 0.05 vs. 0.16 ± 0.02, P < 0.01). The gallbladder responses were also greater when mice were treated with neuropeptide Y (10-8 mol/L: 0.00 ± 0.00 vs. 0.00 ± 0.00, NS; 10-7 mol/L: 0.12 ± 0.02 vs. 0.05 ± 0.01, P < 0.01; 10-6 mol/L: 0.26 ± 0.08 vs. 0.06 ± 0.01, P < 0.01) and cholecystokinin (10-10 mol/L: 0.27 ± 0.04 vs. 0.13 ± 0.02, P < 0.01; 10-9 mol/L: 0.59 ± 0.08 vs. 0.27 ± 0.04, P < 0.01; 10-8 mol/L: 0.80 ± 0.11 vs. 0.37 ± 0.05, P < 0.01; 10-7 mol/L: 0.86 ± 0.11 vs. 0.44 ± 0.06, P < 0.01). These data suggest that genetically obese, leptin-deficient mice have decreased responses to acetylcholine, neuropeptide Y, and cholecystokinin. We conclude that decreased gallbladder motility contributes to the increased incidence of gallstones associated with obesity.

Ventral Hernia Management: Expert Consensus Guided by Systematic Review.

Objective: To achieve consensus on the best practices in the management of ventral hernias (VH). Background: Management patterns for VH are heterogeneous, often with little supporting evidence or correlation with existing evidence. Methods: A systematic review identified the highest level of evidence available for each topic. A panel of expert hernia-surgeons was assembled. Email questionnaires, evidence review, panel discussion, and iterative voting was performed. Consensus was when all experts agreed on a management strategy. Results: Experts agreed that complications with VH repair (VHR) increase in obese patients (grade A), current smokers (grade A), and patients with glycosylated hemoglobin (HbA1C) ≥ 6.5% (grade B). Elective VHR was not recommended for patients with BMI ≥ 50 kg/m2 (grade C), current smokers (grade A), or patients with HbA1C ≥ 8.0% (grade B). Patients with BMI= 30–50 kg/m2 or HbA1C = 6.5–8.0% require individualized interventions to reduce surgical risk (grade C, grade B). Nonoperative management was considered to have a low-risk of short-term morbidity (grade C). Mesh reinforcement was recommended for repair of hernias ≥ 2 cm (grade A). There were several areas where high-quality data were limited, and no consensus could be reached, including mesh type, component separation technique, and management of complex patients. Conclusions: Although there was consensus, supported by grade A–C evidence, on patient selection, the safety of short-term nonoperative management, and mesh reinforcement, among experts; there was limited evidence and broad variability in practice patterns in all other areas of practice. The lack of strong evidence and expert consensus on these topics has identified gaps in knowledge where there is need of further evidence.

Multicenter, prospective, longitudinal study of the recurrence, surgical site infection, and quality of life after contaminated ventral hernia repair using biosynthetic absorbable mesh: The COBRA study

OBJECTIVE The aim of the study was to evaluate biosynthetic absorbable mesh in single-staged contaminated (Centers for Disease Control class II and III) ventral hernia (CVH) repair over 24 months. BACKGROUND CVH has an increased risk of postoperative infection. CVH repair with synthetic or biologic meshes has reported chronic biomaterial infections and high hernia recurrence rates. METHODS Patients with a contaminated or clean-contaminated operative field and a hernia defect at least 9 cm had a biosynthetic mesh (open, sublay, retrorectus, or intraperitoneal) repair with fascial closure (n = 104). Endpoints included overall Kaplan-Meier estimates for hernia recurrence and postoperative wound infection rates at 24 months, and the EQ-5D and Short Form 12 Health Survey (SF-12). Analyses were conducted on the intent-to-treat population, and health outcome measures evaluated using paired t tests. RESULTS Patients had a mean age of 58 years, body mass index of 28 kg/m, 77% had contaminated wounds, and 84% completed 24-months follow-up. Concomitant procedures included fistula takedown (n = 24) or removal of infected previously placed mesh (n = 29). Hernia recurrence rate was 17% (n = 16). At the time of CVH repair, intraperitoneal placement of the biosynthetic mesh significantly increased the risk of recurrences (P ≤ 0.04). Surgical site infections (19/104) led to higher risk of recurrence (P < 0.01). Mean 24-month EQ-5D (index and visual analogue) and SF-12 physical component and mental scores improved from baseline (P < 0.05). CONCLUSIONS In this prospective longitudinal study, biosynthetic absorbable mesh showed efficacy in terms of long-term recurrence and quality of life for CVH repair patients and offers an alternative to biologic and permanent synthetic meshes in these complex situations.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. http://creativecommons.org/licenses/by-nc-nd/4.0.Objective: The aim of the study was to evaluate biosynthetic absorbable mesh in single-staged contaminated (Centers for Disease Control class II and III) ventral hernia (CVH) repair over 24 months. Background: CVH has an increased risk of postoperative infection. CVH repair with synthetic or biologic meshes has reported chronic biomaterial infections and high hernia recurrence rates. Methods: Patients with a contaminated or clean-contaminated operative field and a hernia defect at least 9 cm2 had a biosynthetic mesh (open, sublay, retrorectus, or intraperitoneal) repair with fascial closure (n = 104). Endpoints included overall Kaplan-Meier estimates for hernia recurrence and postoperative wound infection rates at 24 months, and the EQ-5D and Short Form 12 Health Survey (SF-12). Analyses were conducted on the intent-to-treat population, and health outcome measures evaluated using paired t tests. Results: Patients had a mean age of 58 years, body mass index of 28 kg/m2, 77% had contaminated wounds, and 84% completed 24-months follow-up. Concomitant procedures included fistula takedown (n = 24) or removal of infected previously placed mesh (n = 29). Hernia recurrence rate was 17% (n = 16). At the time of CVH repair, intraperitoneal placement of the biosynthetic mesh significantly increased the risk of recurrences (P ⩽ 0.04). Surgical site infections (19/104) led to higher risk of recurrence (P < 0.01). Mean 24-month EQ-5D (index and visual analogue) and SF-12 physical component and mental scores improved from baseline (P < 0.05). Conclusions: In this prospective longitudinal study, biosynthetic absorbable mesh showed efficacy in terms of long-term recurrence and quality of life for CVH repair patients and offers an alternative to biologic and permanent synthetic meshes in these complex situations.

Heating and humidifying of carbon dioxide during pneumoperitoneum is not indicated: A prospective randomized trial

BackgroundCarbon dioxide (CO2) pneumoperitoneum usually is created by a compressed gas source. This exposes the patient to cool dry gas delivered at room temperature (21°C) with 0% relative humidity. Various delivery methods are available for humidifying and heating CO2 gas. This study was designed to determine the effects of heating and humidifying gas for the intraabdominal environment.MethodsFor this study, 44 patients undergoing laparoscopic Roux-en-Y gastric bypass were randomly assigned to one of four arms in a prospective, randomized, single-blinded fashion: raw CO2 (group 1), heated CO2 (group 2), humidified CO2 (group 3), and heated and humidified CO2 (group 4). A commercially available CO2 heater–humidifier was used. Core temperatures, intraabdominal humidity, perioperative data, and postoperative outcomes were monitored. Peritoneal biopsies were taken in each group at the beginning and end of the case. Biopsies were subjected staining protocols designed to identify structural damage and macrophage activity. Postoperative narcotic use, pain scale scores, recovery room time, and length of hospital stay were recorded. One-way analysis of variance (ANOVA) and the nonparametric Kruskal–Wallis test were used to compare the groups.ResultsDemographics, volume of CO2 used, intraabdominal humidity, bladder temperatures, lens fogging, and operative times were not significantly different between the groups. Core temperatures were stable, and intraabdominal humidity measurements approached 100% for all the patients over the entire procedure. Total narcotic dosage and pain scale scores were not statistically different. Recovery room times and length of hospital stay were similar in all the groups. Only one biopsy in the heated–humidified group showed an increase in macrophage activity.ConclusionsThe intraabdominal environment in terms of temperature and humidity was similar in all the groups. There was no significant difference in the intraoperative body temperatures or the postoperative variable measured. No histologic changes were identified. Heating or humidifying of CO2 is not justified for patients undergoing laparoscopic bariatric surgery.

Design and implementation of the Americas Hernia Society Quality Collaborative (AHSQC): improving value in hernia care

PurposeWide variation in care and costs exists regarding the management of abdominal wall hernias, with unproven benefit for many therapies. This work establishes a specialty society-based solution to improve the quality and value of care delivered to hernia patients during routine clinical management on a national scale.MethodsThe Americas Hernia Society Quality Task Force was charged by the Americas Hernia Society leadership to develop an initiative that utilizes the concepts of continuous quality improvement (CQI). A disease-based registry was created to collect information for CQI incorporating real-time outcome reporting, patient reported outcomes, stakeholder engagement, and collaborative learning methods to form a comprehensive quality improvement effort.ResultsThe Americas Hernia Society Quality Collaborative (AHSQC) was formed with the mission to provide health care professionals real-time information for maximizing value in hernia care. The initial disease areas selected for CQI were incisional and parastomal hernias with ten priorities encompassing the spectrum of care. A prospective registry was created with real-time analytic feedback to surgeons. A data assurance process was implemented to ensure maximal data quality and completeness. Four collaborative meetings per year were established to meet the goals of the AHSQC. As of the fourth quarter 2014, the AHSQC includes nearly 2377 patients at 38 institutions with 82 participating surgeons.ConclusionsThe AHSQC has been established as a quality improvement initiative utilizing concepts of CQI. This ongoing effort will continually refine its scope and goals based on stakeholder input to improve care delivered to hernia patients.

Diabetes and hyperlipidemia correlate with gallbladder contractility in leptin-related murine obesity

Obesity is associated with many comorbid conditions including diabetes, hyperlipidemia, and gallstones. However, the interaction among these modalities remains unclear. We recently demonstrated that both leptin-deficient and leptin-resistant obese mice have impaired biliary motility. These obese mice also are diabetic and hyperlipidemic. Therefore, we tested the hypothesis that serum glucose, insulin, cholesterol, and triglyceride levels would correlate with gallbladder contractility. Thirty-four lean control, 10 lean heterozygous leptin-deficient, 18 obese homozygous leptin-deficient, and 12 obese homozygous leptin-resistant mice were fed a nonlithogenic chow diet while nine lean control and nine obese homozygous leptin-deficient mice were fed a high-cholesterol diet for 4 weeks. In vitro gallbladder responses to cholecystokinin (CCK; 10-8 mol/L), acetylcholine (ACh; 10-5 mol/L), and neuropeptide Y (NPY; 10-6 mol/L) were measured. Serum glucose, insulin, cholesterol, and triglyceride levels were measured from pooled serum from an additional 704 animals. Gallbladder responses were greatest for CCK, intermediate for ACh, and least for NPY. Serum glucose, insulin, cholesterol, and triglyceride levels and body weight all correlated similarly, negatively, and significantly (P < 0.001) with gallbladder contractility. Hyperglycemia, insulin-resistance, hyperlipidemia, and body weight in obese mice with leptin dysfunction are associated with poor gallbladder contractility, which in turn may contribute to the association between obesity and gallstone formation.

Nonalcoholic fatty gallbladder disease : The influence of diet in lean and obese mice

The obesity epidemic has contributed to an increased prevalence of gallstones and a higher percentage of chronic acalculous cholecystitis. Obesity is associated with Type II diabetes and hyperlipidemia in murine models. In addition, we have previously demonstrated that serum glucose, insulin, cholesterol, and triglycerides correlated with gallbladder contractility in murine models. However, the relative role of in sulin resistance and gallbladder fat infiltration in this phenomenon remain unclear. Therefore, we tested the hypothesis that gallbladder wall lipids are related to obesity and diet and are inversely correlated with gallbladder contractility. One hundred lean control (C7BL/6J) and 36 obese leptin-deficient (Lepob) 8-week-old female mice were fed either a chow diet or a 1.0% cholesterol, 15% butterfat (high-lipid) diet for four weeks. Pooled gallbladders were then analyzed for free fatty acids (FFA), phospholipids (PL), total cholesterol (TC), and triglycerides (TG). Cholesterol/phospholipid ratios were then calculated. The Lepob mice fed a chow diet had significantly higher (P<0.01) gallbladder lipids than the three other groups. The lean mice that were fed a high-lipid diet had increased (P<0.05) gallbladder TC compared to the lean mice on a chow diet. In addition, the cholesterol/phospholipid ratio was significantly in creased (P<0.01) in the lean mice fed a high-lipid diet compared to the other three groups. Finally, the high-lipid diet decreased gallbladder FFA (P<0.01), PL (P=0.08), and TC (P<0.05) in Lepob mice. These data suggest that (1) obese mice have increased gallbladder lipids; (2) a high-cholesterol, high-fat diet increases gallbladder lipids and the cholesterol/phospholipid ratio in lean mice; but (3) de creases gallbladder fatty acids, phospholipids, and cholesterol in obese mice. Prior studies have docu mented similarly decreased gallbladder response to neurotransmitters in obese mice on a chow diet, as well as lean and obese mice on a high-lipid diet. Therefore, we conclude that leptin-deficient obesity and/or a high-fat diet causes nonalcoholic fatty gallbladder disease, which is manifested by diminished gallbladder contractility.

Validation of a virtual reality-based robotic surgical skills curriculum

BackgroundThe clinical application of robotic-assisted surgery (RAS) is rapidly increasing. The da Vinci Surgical System™ is currently the only commercially available RAS system. The skills necessary to perform robotic surgery are unique from those required for open and laparoscopic surgery. A validated laparoscopic surgical skills curriculum (fundamentals of laparoscopic surgery or FLS™) has transformed the way surgeons acquire laparoscopic skills. There is a need for a similar skills training and assessment tool specific for robotic surgery. Based on previously published data and expert opinion, we developed a robotic skills curriculum. We sought to evaluate this curriculum for evidence of construct validity (ability to discriminate between users of different skill levels).MethodsFour experienced surgeons (>20 RAS) and 20 novice surgeons (first-year medical students with no surgical or RAS experience) were evaluated. The curriculum comprised five tasks utilizing the da Vinci™ Skills Simulator (Pick and Place, Camera Targeting 2, Peg Board 2, Matchboard 2, and Suture Sponge 3). After an orientation to the robot and a period of acclimation in the simulator, all subjects completed three consecutive repetitions of each task. Computer-derived performance metrics included time, economy of motion, master work space, instrument collisions, excessive force, distance of instruments out of view, drops, missed targets, and overall scores (a composite of all metrics).ResultsExperienced surgeons significantly outperformed novice surgeons in most metrics. Statistically significant differences were detected for each task in regards to mean overall scores and mean time (seconds) to completion.ConclusionsThe curriculum we propose is a valid method of assessing and distinguishing robotic surgical skill levels on the da Vinci Si™ Surgical System. Further study is needed to establish proficiency levels and to demonstrate that training on the simulator with the proposed curriculum leads to improved robotic surgical performance in the operating room.

Microbiology of Explanted Suture Segments from Infected and Noninfected Surgical Patients

ABSTRACT Sutures under selective host/environmental factors can potentiate postoperative surgical site infection (SSI). The present investigation characterized microbial recovery and biofilm formation from explanted absorbable (AB) and nonabsorbable (NAB) sutures from infected and noninfected sites. AB and NAB sutures were harvested from noninfected (70.9%) and infected (29.1%) sites in 158 patients. At explantation, devices were sonicated and processed for qualitative/quantitative bacteriology; selective sutures were processed for scanning electron microscopy (SEM). Bacteria were recovered from 85 (53.8%) explanted sites; 39 sites were noninfected, and 46 were infected. Suture recovery ranged from 11.1 to 574.6 days postinsertion. A significant difference in mean microbial recovery between noninfected (1.2 isolates) and infected (2.7 isolates) devices (P < 0.05) was noted. Staphylococcus epidermidis, Staphylococcus aureus, coagulase-negative staphylococci (CNS), Peptostreptococcus spp., Bacteroides fragilis, Escherichia coli, Enterococcus spp., Pseudomonas aeruginosa, and Serratia spp. were recovered from infected devices, while commensal skin flora was recovered from noninfected devices. No significant difference in quantitative microbial recovery between infected monofilament and multifilament sutures was noted. Biofilm was present in 100% and 66.6% of infected and noninfected devices, respectively (P < 0.042). We conclude that both monofilament and braided sutures provide a hospitable surface for microbial adherence: (i) a significant difference in microbial recovery from infected and noninfected sutures was noted, (ii) infected sutures harbored a mixed flora, including multidrug-resistant health care-associated pathogens, and (iii) a significant difference in the presence or absence of a biofilm in infected versus noninfected explanted devices was noted. Further studies to document the benefit of focused risk reduction strategies to minimize suture contamination and biofilm formation postimplantation are warranted.

Proficiency training on a virtual reality robotic surgical skills curriculum

AbstractIntroduction The clinical application of robotic surgery is increasing. The skills necessary to perform robotic surgery are unique from those required in open and laparoscopic surgery. A validated laparoscopic surgical skills curriculum (Fundamentals of Laparoscopic Surgery or FLS™) has transformed the way surgeons acquire laparoscopic skills. There is a need for a similar skills training and assessment tool for robotic surgery. Our research group previously developed and validated a robotic training curriculum in a virtual reality (VR) simulator. We hypothesized that novice robotic surgeons could achieve proficiency levels defined by more experienced robotic surgeons on the VR robotic curriculum, and that this would result in improved performance on the actual daVinci Surgical System™.Methods25 medical students with no prior robotic surgery experience were recruited. Prior to VR training, subjects performed 2 FLS tasks 3 times each (Peg Transfer, Intracorporeal Knot Tying) using the daVinci Surgical System™ docked to a video trainer box. Task performance for the FLS tasks was scored objectively. Subjects then practiced on the VR simulator (daVinci Skills Simulator) until proficiency levels on all 5 tasks were achieved before completing a post-training assessment of the 2 FLS tasks on the daVinci Surgical System™ in the video trainer box.ResultsAll subjects to complete the study (1 dropped out) reached proficiency levels on all VR tasks in an average of 71 (± 21.7) attempts, accumulating 164.3 (± 55.7) minutes of console training time. There was a significant improvement in performance on the robotic FLS tasks following completion of the VR training curriculum.ConclusionsNovice robotic surgeons are able to attain proficiency levels on a VR simulator. This leads to improved performance in the daVinci surgical platform on simulated tasks. Training to proficiency on a VR robotic surgery simulator is an efficient and viable method for acquiring robotic surgical skills.