Intentional enterotomies: validation of a novel robotic surgery training exercise.

While laparoscopic simulation-based training is a well-established component of general surgery training, no such requirement or standardized curriculum exists for robotic surgery. Furthermore, there is a lack of high-fidelity electrocautery simulation training exercises in the literature. Using Messick's validity framework, we sought to determine the content, response process, internal content and construct validity of a novel inanimate tissue model that utilizes electrocautery for potential incorporation in such curricula. A multi-institutional, prospective study involving medical students (MS) and general surgery residents (PGY1-3) was conducted. Participants performed an exercise using a biotissue bowel model on the da Vinci Xi robotic console during which they created an enterotomy using electrocautery, followed by approximation with interrupted sutures. Participant performance was recorded and then scored by crowd-sourced assessors of technical skill, along with three of the authors. Construct validity was determined via difference in Global Evaluative Assessment of Robotic Skills (GEARS) score, time to completion, and total number of errors between the two cohorts. Upon completion of the exercise, participants were surveyed on their perception of the exercise and its impact on their robotic training to determine content validity. 31 participants were enrolled and separated into two cohorts: MS + PGY1 vs. PGY2-3. Time spent on the robotic trainer (0.8 vs. 8.13 h, p = 0.002), number of bedside robotic assists (5.7 vs. 14.8, p < 0.001), and number of robotic cases as primary surgeon (0.3 vs. 13.1, p < 0.001) were statistically significant between the two groups. Differences in GEARS scores (18.5 vs. 19.9, p = 0.001), time to completion (26.1 vs. 14.4 min, p < 0.001), and total errors (21.5 vs. 11.9, p = 0.018) between the groups were statistically significant as well. Of the 23 participants that completed the post-exercise survey, 87% and 91.3% reported improvement in robotic surgical ability and confidence, respectively. On a 10-point Likert scale, respondents rated the realism of the exercise 7.5, educational benefit 9.1, and effectiveness in teaching robotic skills 8.7. Controlling for the upfront investment of certain training materials, each exercise iteration cost ~ $30. This study confirmed the content, response process, internal structure and construct validity of a novel, high-fidelity and cost-effective inanimate tissue exercise which successfully incorporates electrocautery. Consideration should be given to its addition to robotic surgery training programs.

Model Development of a Novel Robotic Surgery Training Exercise With Electrocautery.

Robot-assisted surgery (RAS) has undergone rapid adoption in general surgery due to features such as three-dimensional visualization, wrist dexterity, improved precision of movement, and operator ergonomics. While many surgical trainees encounter RAS during their residency, robotic skills training programs and curricula vary across institutions and there is broad variation in graduating general surgeons' robotic proficiency levels. Due to a need for a formalized process to achieve competence on the robotic platform, simulation-based training has become instrumental in closing this gap as it provides training in a low-stakes environment while allowing the trainee to improve their psychomotor and basic procedural skills. Several different models of simulation training exist including virtual reality, animal, cadaveric, and inanimate tissue platforms. Each form of training has its own merits and limitations. While virtual reality platforms have been well evaluated for face, content, and construct validity, their initial set-up costs can be as high as $125,000. Similarly, animal and cadaveric models are not only costly but also have ethical considerations that may preclude participation. There is an unmet need in developing high-fidelity, cost-effective simulations for basic videoscopic skills such as cautery use. We developed a cost-effective and high-fidelity inanimate tissue model that incorporates electrocautery. Using a double-layered bowel model secured to a moistened household sponge, this inanimate exercise simulates fundamental skills of robotic surgery such as tissue handling, camera control, suturing, and electrocautery.

A practical guide to appendicitis evaluation and treatment.

Which clinical findings most reliably point to appendicitis? How do the 3 primary clinical scoring systems compare? When is it time to order imaging studies?

Maximizing Benefit of Virtual Learning: Lessons From the Coronavirus Disease 2019 Pandemic.

INTRODUCTION: The coronavirus disease 2019 pandemic has profoundly impacted surgical education. We assessed resident perceptions of our virtual academic program, which consists of daily lectures or case conferences held via a videoconferencing platform. METHODS: A survey evaluating attitudes and practices for virtual academics was administered to general surgery residents. A focus group was conducted to identify benefits, barriers to engagement, and opportunities for improvement for virtual education. A total of 19 residents completed the education survey, and seven residents participated in the focus group. RESULTS: While expressing preference toward in-person academics (84.2%), residents felt the virtual academics were of good quality (median rating 4/5) and preferred virtual academics to no academic sessions (94.7%). Of respondents, 57.9% believe that the coronavirus pandemic negatively impacted their surgical education. They believe their American Board of Surgery In-Training Examination preparation was not impacted. Residents preferred using a computer over a phone for academics (79% versus 16%). The focus group identified the benefits of virtual academics, including the ability to participate while away and having recordings available. Areas for improvement included reinforcement of protected time for academics, requiring cameras be on, increasing in-lecture polls, and creation of an online repository of recordings for review. Residents hoped a virtual component of academics and recordings would continue past the pandemic. CONCLUSIONS: Although virtual academics are not the preferred mode of learning in our residency, there are multiple unintended benefits. We recommend a hybrid academic model with in-person didactics and recorded video for later review.

Extracorporeal Filtration of Potassium in a Swine Model of Bilateral Hindlimb Ischemia-Reperfusion Injury With Severe Acute Hyperkalemia.

Introduction: Options for the treatment of hyperkalemia in the pre-hospital setting are limited, particularly in the context of natural disaster or during combat operations. Contemporary interventions require extensive resources and technical expertise. Here we examined the potential for a simple, field deployable bridge-dialysis as a countermeasure for acute hyperkalemia induced by prolonged ischemia-reperfusion. Methods: Twenty female swine were randomized into two experimental groups undergoing a 2-hour bilateral hindlimb ischemia-reperfusion injury. Subsequent to injury, hemoperfusion was performed in the presence (Column) and absence (Sham Control) of a high-affinity potassium-binding column (CytoSorbents, Monmouth Junction, NJ, USA). Serial blood gas and chemistries were sampled. Primary endpoint was changed in serum potassium concentrations post-injury and filtration. Results: Serum potassium was significantly elevated following ischemia-reperfusion injury in both groups (149% (12) and 150% (22), p < 0.05 vs respective baseline values). There were no differences observed between groups in respect to physiologic parameters; mean arterial pressure, heart rate, systemic vascular resistance, cardiac output, or central venous oxygenation. Filtration resulted in a significant relative decrease in potassium compared with controls after the first hour as determined by repeated measures two-way ANOVA (p < 0.0001) which continued through end of the study. Significant thrombocytopenia was observed in animals undergoing filtration with a mean reduction in platelets measured at T = 480 minutes (168 × 103µL, p < 0.0001 vs baseline). Conclusions: We demonstrate that serum potassium can be filtered via hemoperfusion utilizing a simple extracorporeal potassium-binding platform, though evolution of this technology will be required to achieve meaningful reduction of potassium in clinically significant hyperkalemia after trauma.

Antimicrobial-bonded graft patency in the setting of a polymicrobial infection in swine (Sus scrofa).

BACKGROUND: Polytetrafluoroethylene (PTFE) and Dacron are commonly used as arterial conduits in vascular trauma or infection when vein interposition graft may not be available. This study used a previously validated large animal model of polymicrobial infection to assess the patency and infectious resistance of a novel, antibiotic-impregnated graft material compared with PTFE and Dacron. METHODS: Forty-eight animals were placed into five groups for a 21-day survival period. A 6-mm PTFE, Dacron, or antimicrobial-bonded graft was used to replace the iliac artery and then inoculated with 1 × 107 colonies/mL of genetically labeled Pseudomonas aeruginosa and Staphylococcus aureus. Native vessels with and without contamination served as control groups. The primary end points were graft patency (determined by duplex ultrasound and necropsy) and graft infection (culture with molecular analysis). Secondary end points included physiologic measurements, blood cultures, laboratory data, and histopathology. RESULTS: At 21 days, 50% of PTFE, 62.5% of Dacron, and 100% of the antimicrobial-bonded grafts remained patent (P = .04). PTFE and Dacron had an equivalent number of overall infections, 87.5% and 75%, respectively (P = 1.0). There was no significant difference of infectious organisms between standard materials. The infection rate of the antimicrobial-bonded graft (25%) was significantly less than that of both PTFE and Dacron (P < .01), and all of these infections were secondary to P. aeruginosa. Clinical data did not vary significantly between groups. There were no mortalities in the protocol secondary to graft blowout or sepsis. CONCLUSIONS: The antimicrobial-bonded graft material outperformed standard PTFE and Dacron in the setting of polymicrobial infection with regard to graft patency and infection. The novel prosthetic material appears to be resistant to infection with S. aureus and to limit the growth of P. aeruginosa. Additional studies are recommended to explore the role of this antibiotic-bonded graft for use in the setting of vascular infection or trauma.

Prosthetic Graft Patency in the Setting of a Polymicrobial Infection in Swine (Sus scrofa).

BACKGROUND: In the setting of vascular injury, vein interposition graft is the preferred conduit, but may have limited availability. This study seeks to develop a large animal model assessing the graft performance of polytetrafluoroethylene (PTFE) and Dacron in the setting of a polymicrobial infection. METHODS: Thirty-seven animals were placed into 4 groups for a 21-day survival period. Six-millimeter PTFE or Dacron interposition grafts were placed in the right iliac artery with a standardized bacterial inoculation. Native vessel with and without contamination served as control groups. The inoculant was 1 × 107 of genetically labeled Pseudomonas aeruginosa and Staphylococcus aureus. The primary end points were graft patency (determined by duplex ultrasound and necropsy) and graft infection (culture with molecular analysis). Secondary end points included physiological measurements, blood cultures, laboratory data, and histopathology. RESULTS: PTFE and Dacron had similar infection rates of 85.7% and 75%, respectively. There was no significant difference in infectious organisms between graft materials. PTFE and Dacron exhibited bacterial ingrowth and transmigration to the intraluminal portion of the conduit. Forty-five percent of the Dacron group and 40% of the PTFE group remained patent at postoperative day 21 (P = 0.98). Clinical data, including white blood cell count, percent neutrophils, and lactate, did not vary significantly between groups. CONCLUSIONS: PTFE and Dacron perform similarly in terms of infection rates and graft failure as both have a propensity toward bacterial ingrowth and occlusion when compared with controls. This is a valid animal model to assess graft performance in the setting of polymicrobial infection and provides an avenue for studying novel prosthetic conduits.

Simulation and qualitative analysis of glucose variability, mean glucose, and hypoglycemia after subcutaneous insulin therapy for stress hyperglycemia.

BACKGROUND: The critically ill can have persistent dysglycemia during the "subacute" recovery phase of their illness because of altered gene expression; it is also not uncommon for these patients to receive continuous enteral nutrition during this time. The optimal short-acting subcutaneous insulin therapy that should be used in this clinical scenario, however, is unknown. Our aim was to conduct a qualitative numerical study of the glucose-insulin dynamics within this patient population to answer the above question. This analysis may help clinicians design a relevant clinical trial. METHODS: Eight virtual patients with stress hyperglycemia were simulated by means of a mathematical model. Each virtual patient had a different combination of insulin resistance and insulin deficiency that defined their unique stress hyperglycemia state; the rate of gluconeogenesis was also doubled. The patients received 25 injections of subcutaneous regular or Lispro insulin (0-6 U) with 3 rates of continuous nutrition. The main outcome measurements were the change in mean glucose concentration, the change in glucose variability, and hypoglycemic episodes. These end points were interpreted by how the ultradian oscillations of glucose concentration were affected by each insulin preparation. RESULTS: Subcutaneous regular insulin lowered both mean glucose concentrations and glucose variability in a linear fashion. No hypoglycemic episodes were noted. Although subcutaneous Lispro insulin lowered mean glucose concentrations, glucose variability increased in a nonlinear fashion. In patients with high insulin resistance and nutrition at goal, "rebound hyperglycemia" was noted after the insulin analog was rapidly metabolized. When the nutritional source was removed, hypoglycemia tended to occur at higher Lispro insulin doses. Finally, patients with severe insulin resistance seemed the most sensitive to insulin concentration changes. CONCLUSIONS: Subcutaneous regular insulin consistently lowered mean glucose concentrations and glucose variability; its linear dose-response curve rendered the preparation better suited for a sliding-scale protocol. The longer duration of action of subcutaneous regular insulin resulted in better glycemic-control metrics for patients who were continuously postprandial. Clinical trials are needed to examine whether these numerical results represent the glucose-insulin dynamics that occur in intensive care units; if present, their clinical effects should be evaluated.

Comparison of Subcutaneous Regular Insulin and Lispro Insulin in Diabetics Receiving Continuous Nutrition: A Numerical Study.

BACKGROUND: Optimal management of non-critically ill patients with diabetes maintained on continuous enteral feeding (CEN) is poorly defined. Subcutaneous (SQ) lispro and SQ regular insulin were compared in a simulated type 1 and type 2 diabetic patient receiving CEN. METHOD: A glucose-insulin feedback mathematical model was employed to simulate type 1 and type 2 diabetic patients on CEN. Each patient received 25 SQ injections of regular insulin or insulin lispro, ranging from 0-6 U. Primary endpoints were the change in mean glucose concentration (MGC) and change in glucose variability (GV); hypoglycemic episodes were also reported. The model was first validated against patient data. RESULTS: Both SQ insulin preparations linearly decreased MGC, however, SQ regular insulin decreased GV whereas SQ lispro tended to increase GV. Hourly glucose concentration measurements were needed to capture the increase in GV. In the type 2 diabetic patient, "rebound hyperglycemia" occurred after SQ lispro was rapidly metabolized. Although neither SQ insulin preparation caused hypoglycemia, SQ lispro significantly lowered MGC compared to SQ regular insulin. Thus, it may be more likely to cause hypoglycemia. Analyses of the detailed glucose concentration versus time data suggest that the inferior performance of lispro resulted from its shorter duration of action. Finally, the effects of both insulin preparations persisted beyond their duration of actions in the type 2 diabetic patient. CONCLUSIONS: Subcutaneous regular insulin may be the short-acting insulin preparation of choice for this subset of diabetic patients. Clinical trial is required before a definitive recommendation can be made.

A technique for endograft relining of a type IV endoleak using a surgeon-modified internal gate.

Type IV endoleaks represent a rare etiology of late endograft failure; however, depending on the location, they can be extremely challenging to repair with endovascular solutions. We present a method of endograft relining that preserves antegrade limb perfusion, avoids extra-anatomic reconstructions, and ensures complete endograft exclusion.