Development of an in vitro ventricular shunt material testing model and utility of PEG as antifouling coating.

OBJECTIVE: CSF shunts, most commonly the ventriculoperitoneal shunt, remain a first and last line of management for children and adults with hydrocephalus. However, the failure rates of these shunts are extremely high, leaving many patients with the need for revision surgical procedures. The objective of this study was to develop a model to assess the efficacy of a nonfouling ventricular catheter. A second objective was to test polyethylene glycol (PEG) as an antifouling coating. METHODS: Microglial cells were grown on medical-grade catheter silicone with biofouling simulated by collagen incubation over a range of concentrations from 31 to 103 µg/ml and durations from 2 to 18 hours. After ideal fouling conditions were identified, catheter silicone was then coated with PEG as an antifouling surface, and cell growth on this surface was compared to that on uncoated standard catheter silicone. RESULTS: Collagen biofouling increased cell growth on silicone surfaces with an ideal concentration of 69 µg/ml and incubation of 6 hours. PEG coating of silicone catheter material yielded 70-fold lower cell growth (p < 0.0001), whereas collagen-fouled PEG-coated silicone yielded 157-fold lower cell growth (p < 0.0001). CONCLUSIONS: Catheter coating significantly reduced cell growth, particularly in the setting of biofouling. The application of antifouling surfaces to ventricular shunts shows considerable promise for improving efficacy.

A National Study on Training Innovation in US Medical Education.

Introduction Traditional medical education has leaned heavily on memorization, pattern recognition, and learned algorithmic thinking. Increasingly, however, creativity and innovation are becoming recognized as a valuable component of medical education. In this national survey of Association of American Medical Colleges (AAMC) member institutions, we seek to examine the current landscape of exposure to innovation-related training within the formal academic setting. Methods Surveys were distributed to 168 of 171 AAMC-member institutions (the remaining three were excluded from the study for lack of publicly available contact information). Questions assessed exposure for medical students among four defined innovation pillars as follows: (1) medical humanities, (2) design thinking, (3) entrepreneurship, or (4) technology transfer. Chi-squared analysis was used to assess statistical significance between schools, comparing schools ranked in the top 20 by the US News and World Report against non-top 20 respondents, and comparing schools that serve as National Institutes of Health (NIH) Clinical and Translational Science Awards (CTSA) program hubs against non-CTSA schools. Heat maps for geospatial visualization of data were created using ArcGIS (ArcMAP 10.6) software (Redlands, CA: Environmental Systems Research Institute). Results The overall response rate was 94.2% with 161 schools responding. Among respondents, 101 (63%) reported having medical humanities curricula at their institution. Design thinking offerings were noted at 51/161 (32%) institutions. Support for entrepreneurship was observed at 51/161 institutions (32%), and technology transfer infrastructure was confirmed at 42/161 (26%) of institutions. No statistically significant difference was found between top 20 schools and lower 141 schools when comparing schools with no innovation programs or one or more innovation programs (p=0.592), or all four innovation programs (p=0.108). CTSA programs, however, did show a statistically significant difference (p<0.00001) when comparing schools with no innovation programs vs. one or more programs, but not when comparing to schools with all four innovation programs (p=0.639). Conclusion This study demonstrated an overwhelming prevalence of innovation programs in today's AAMC medical schools, with over 75% of surveyed institutions offering at least one innovation program. No statistically significant trend was seen in the presence of zero programs, one or more, or all four programs between top 20 programs and the remaining 141. CTSA hub schools, however, were significantly more likely to have at least one program vs. none compared to non-CTSA hub schools. Future studies would be valuable to assess the long-term impact of this trend on medical student education.

Pilot study of responsive nucleus accumbens deep brain stimulation for loss-of-control eating.

Cravings that precede loss of control (LOC) over food consumption present an opportunity for intervention in patients with the binge eating disorder (BED). In this pilot study, we used responsive deep brain stimulation (DBS) to record nucleus accumbens (NAc) electrophysiology during food cravings preceding LOC eating in two patients with BED and severe obesity (trial registration no. NCT03868670). Increased NAc low-frequency oscillations, prominent during food cravings, were used to guide DBS delivery. Over 6 months, we observed improved self-control of food intake and weight loss. These findings provide early support for restoring inhibitory control with electrophysiologically-guided NAc DBS. Further work with increased sample sizes is required to determine the scalability of this approach.

Beyond 5 years: a matched cohort of sleeve gastrectomy versus gastric bypass.

BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) has demonstrated excellent short-term outcomes. However, existing studies suffer from loss to follow-up, and most long-term data focus on laparoscopic Roux-en-Y gastric bypass (LRYGB). This study compares weight loss in patients ≥5 years from LSG with that in matched patients who underwent LRYGB. OBJECTIVES: The purpose of this study was to compare long-term weight loss in patients undergoing LRYGB and LSG. SETTING: University hospital, United States. METHODS: We retrospectively evaluated patients who underwent LSG before August 2012 with follow-up data ≥5 years. LSG patients were matched 1:1 with LRYGB patients by sex, age at surgery, and preoperative body mass index. Univariate and multivariate analyses were performed with weight loss at the longest duration the primary outcome. RESULTS: One-hundred and sixty-five patients underwent LSG during the study period. Long-term follow-up data (≥5 years) were available for 85 patients (52%). There were no preoperative differences between those with and without follow-up data. Six LSG patients (7%) were excluded because they underwent reoperation that altered intestinal anatomy. Of the 79 patients remaining, 75 were matched with post-LRYGB patients. The average follow-up period was 6.4 years for LSG patients and 6.5 years for LRYGB patients (P = .08, not significant). Change in body mass index was 6.81 kg/m2 for LSG patients and 13.11 kg/m2 for LRYGB patients. Percentage of total body weight loss was 15.25% for LSG patients and 28.73% for LRYGB patients. Percentage of excess body weight loss was 37% for LSG patients and 67% for LRYGB patients (P < .0001). Weight loss for LSG patient follow-up in clinic versus outside the clinic was 46% versus 34% (P = .18, not significant). CONCLUSIONS: LSG is now the most common bariatric surgery in the United States. Long-term data are needed to confirm that observed short-term favorable outcomes are maintained. Recent studies have produced divergent results. We observed significantly less weight loss at ≥5 years in LSG patients compared with matched LRYGB patients.

Can responsive deep brain stimulation be a cost-effective treatment for severe obesity?

OBJECTIVE: A first-in-human responsive deep brain stimulation (rDBS) trial (NCT03868670) for obesity is under way, which is based on promising preclinical evidence. Given the upfront costs of rDBS, it is prudent to examine the success threshold for cost-effectiveness compared with laparoscopic Roux-en-Y gastric bypass (LRYGB). METHODS: Efficacy and safety data on LRYGB and safety data on rDBS were collected for established indications through a literature search. The success threshold was defined as minimum BMI reduction. Treatment costs were calculated via Medicare national reimbursement data. RESULTS: LRYGB had a mean BMI reduction of 13.75 kg/m2 . Based on adverse events, LRYGB was a less-preferred health state (overall adverse event utility of 0.96 [0.02]) than rDBS (0.98 [0.01]), but LRYGB ($14,366 [$6,410]) had a significantly lower treatment cost than rDBS ($29,951 [$4,490]; p < 0.0001). Therefore, for rDBS to be cost-effective compared with LRYGB, the multiple models yielded a success threshold range of 13.7 to 15.2 kg/m2 . CONCLUSIONS: This study established a preliminary efficacy success threshold for rDBS to be cost-effective for severe obesity, and results from randomized controlled trials are needed. This analysis allows for interpretation of the economic impact of advancing rDBS for obesity in light of ongoing trial results and suggests an attainable threshold is needed for cost-effectiveness.

Gastroesophageal Reflux Disease and the Patient with Obesity.

Patients with obesity who present with gastroesophageal reflux disease (GERD) require a nuanced approach. Those with lower body mass index (BMI) (less than 33) can be counseled on weight loss, and if successful may be approached with laparoscopic fundoplication. Those who are unable to achieve weight loss or those who present with a BMI greater than or equal to 35 should proceed with laparoscopic Roux-en-Y gastric bypass (LRYGB). Conversion to LRYGB from sleeve gastrectomy is a safe and effective way to manage GERD after sleeve gastrectomy.

Innovation in hemodialysis: Using the Biodesign process to identify unmet needs.

There is renewed demand to accelerate innovation in nephrology; public and private sectors are creating programs to support its growth. The Stanford Biodesign innovation process, first developed in 2000, provides a roadmap for health technology and device innovation. There is insufficient published guidance on the application of the Biodesign process in the generation of novel devices to address nephrology- and/or dialysis-related clinical unmet needs. We present "needs finding," the initial part of the identify phase in the Biodesign innovation process and how it may be utilized for nephrology- and/or dialysis-related innovation. We describe here how to apply the Biodesign process to identify unmet dialysis-related needs, with the use of specific case-based examples based on observations within a hemodialysis unit. We then explore how to develop these needs using background research, direct clinical observations, interviews, documentation of observations and interview findings, and development of multiple needs statements. We conclude that there is an opportunity for nephrology innovators to use this methodology broadly in order to identify areas for innovation and initiated the development on novel solutions to be introduced into patient care.

Achalasia: physiology and diagnosis.

Achalasia is a rare motility disorder with incomplete relaxation of the lower esophageal sphincter and ineffective contractions of the esophageal body. It has been hypothesized that achalasia does not result from only one pathway but rather involves a combination of infectious, autoimmune, and familial etiological components. On the basis of other observations, a novel hypothesis suggests that a muscular form of eosinophilic esophagitis is involved in the pathophysiology of achalasia in some patients. This appears to progressively diminish the myenteric plexus at stage III, gradually destroy it at stage II, and finally eliminate it at stage I, the most advanced and final stage of achalasia. Although high-resolution manometry has identified these three different types of achalasia, another subset of patients with a normal-appearing sphincter relaxation has been proposed. Provocative maneuvers, such as the rapid drinking challenge, have recently been demonstrated to improve diagnosis in certain borderline patients, but have to be studied in more detail. However, whether the different types of achalasia will have a long-term impact on tailored therapies is still a matter of debate. Additionally, novel aspects of the standard timed barium swallow appear to be an important adjunct of diagnosis, as it has been shown to have a diagnostic as well as a predictive value.

Brain-Responsive Neurostimulation for Loss of Control Eating: Early Feasibility Study.

BACKGROUND: Loss of control (LOC) is a pervasive feature of binge eating, which contributes significantly to the growing epidemic of obesity; approximately 80 million US adults are obese. Brain-responsive neurostimulation guided by the delta band was previously found to block binge-eating behavior in mice. Following novel preclinical work and a human case study demonstrating an association between the delta band and reward anticipation, the US Food and Drug Administration approved an Investigational Device Exemption for a first-in-human study. OBJECTIVE: To assess feasibility, safety, and nonfutility of brain-responsive neurostimulation for LOC eating in treatment-refractory obesity. METHODS: This is a single-site, early feasibility study with a randomized, single-blinded, staggered-onset design. Six subjects will undergo bilateral brain-responsive neurostimulation of the nucleus accumbens for LOC eating using the RNS® System (NeuroPace Inc). Eligible participants must have treatment-refractory obesity with body mass index ≥ 45 kg/m2. Electrophysiological signals of LOC will be characterized using real-time recording capabilities coupled with synchronized video monitoring. Effects on other eating disorder pathology, mood, neuropsychological profile, metabolic syndrome, and nutrition will also be assessed. EXPECTED OUTCOMES: Safety/feasibility of brain-responsive neurostimulation of the nucleus accumbens will be examined. The primary success criterion is a decrease of ≥1 LOC eating episode/week based on a 28-d average in ≥50% of subjects after 6 mo of responsive neurostimulation. DISCUSSION: This study is the first to use brain-responsive neurostimulation for obesity; this approach represents a paradigm shift for intractable mental health disorders.

Situating Artificial Intelligence in Surgery: A Focus on Disease Severity.

OBJECTIVES: Artificial intelligence (AI) has numerous applications in surgical quality assurance. We assessed AI accuracy in evaluating the critical view of safety (CVS) and intraoperative events during laparoscopic cholecystectomy. We hypothesized that AI accuracy and intraoperative events are associated with disease severity. METHODS: One thousand fifty-one laparoscopic cholecystectomy videos were annotated by AI for disease severity (Parkland Scale), CVS achievement (Strasberg Criteria), and intraoperative events. Surgeons performed focused video review on procedures with ≥1 intraoperative events (n = 335). AI versus surgeon annotation of CVS components and intraoperative events were compared. For all cases (n = 1051), intraoperative-event association with CVS achievement and severity was examined using ordinal logistic regression. RESULTS: Using AI annotation, surgeons reviewed 50 videos/hr. CVS was achieved in ≤10% of cases. Hepatocystic triangle and cystic plate visualization was achieved more often in low-severity cases (P < 0.03). AI-surgeon agreement for all CVS components exceeded 75%, with higher agreement in high-severity cases (P < 0.03). Surgeons agreed with 99% of AI-annotated intraoperative events. AI-annotated intraoperative events were associated with both disease severity and number of CVS components not achieved. Intraoperative events occurred more frequently in high-severity versus low-severity cases (0.98 vs 0.40 events/case, P < 0.001). CONCLUSIONS: AI annotation allows for efficient video review and is a promising quality assurance tool. Disease severity may limit its use and surgeon oversight is still required, especially in complex cases. Continued refinement may improve AI applicability and allow for automated assessment.

Stanford's Biodesign Innovation program: Teaching opportunities for value-driven innovation in surgery.

The Stanford Biodesign Innovation process, which identifies meaningful clinical needs, develops solutions to meet those needs, and plans for subsequent implementation in clinical practice, is an effective training approach for new generations of healthcare innovators. Continued success of this process hinges on its evolution in response to changes in healthcare delivery and an ever-increasing demand for economically viable solutions. In this article, we provide perspective on opportunities for value-driven innovation in surgery and relate these to value-related teaching elements currently integrated in the Stanford Biodesign process.

Novel device to detect enterotomies in real time during laparoscopy: first in human trial during Roux-en-y gastric bypass.

BACKGROUND: Undetected bowel perforations occur in 0.3-1% of laparoscopic surgical procedures with an associated mortality rate of 5.3%. OBJECTIVE: The purpose of the study was to evaluate the clinical feasibility of a novel medical device to accurately detect bowel gas, specifically hydrogen (H2) and methane (CH4), from a sample of gas from the abdominal cavity during laparoscopic surgery when a known bowel wall perforation has occurred. SETTING: University (Academic) Hospital. METHODS: A prospective single arm study was composed of 8 patients undergoing a standard laparoscopic roux-en-y gastric bypass. At seven time points during the operation intra-abdominal gas was pulled from the abdominal cavity and analyzed using the novel device for H2 and CH4. The time points included after insufflation (T1), after first jejunotomy (T2), after closure of jejunotomy (T3), after recycle of carbon dioxide gas (T4), after gastrostomy (T5), after jejunotomy (T6), at procedure end (T7). RESULTS: Eight patients were enrolled in the study; in 7 (87.5%) patients data from all 7 time points were obtained. After the first opening of the small bowel (T2) mean hydrogen levels were significantly increased compared to baseline hydrogen levels (T1, T4, T7) (p < 0.001). At all time points, there was no significant detection of methane. There were no intra-operative or post-operative complications during the study. CONCLUSION: Hydrogen gas is released into the intra-abdominal cavity when bowel is opened and can be detected in real time using a novel device during laparoscopic surgery. The presence or absence of hydrogen directly correlates to whether the bowel is open (perforated) or intact. This device could be used in the future to detect unintended bowel perforations during laparoscopic surgery, prior to the conclusion of the operation. This technology could also potentially lead to novel mechanism for detecting postoperative leaks using gas detection technology.

Nonerosive reflux disease: clinical concepts.

Esophageal symptoms can arise from gastroesophageal reflux disease (GERD) as well as other mucosal and motor processes, structural disease, and functional esophageal syndromes. GERD is the most common esophageal disorder, but diagnosis may not be straightforward when symptoms persist despite empiric acid suppressive therapy and when mucosal erosions are not seen on endoscopy (as for nonerosive reflux disease, NERD). Esophageal physiological tests (ambulatory pH or pH-impedance monitoring and manometry) can be of value in defining abnormal reflux burden and reflux-symptom association. NERD diagnosed on the basis of abnormal reflux burden on ambulatory reflux monitoring is associated with similar symptom response from antireflux therapy for erosive esophagitis. Acid suppression is the mainstay of therapy, and antireflux surgery has a definitive role in the management of persisting symptoms attributed to NERD, especially when the esophagogastric junction is compromised. Adjunctive approaches and complementary therapy may be of additional value in management. In this review, we describe the evaluation, diagnosis, differential diagnosis, and management of NERD.

Needs-Based Innovation in Interventional Radiology: The Biodesign Process.

There are many possible mechanisms for innovation and bringing new technology into the marketplace. The Stanford Biodesign innovation process is based in a deep understanding of clinical unmet needs as the basis for focused ideation and development. By identifying and vetting a compelling unmet need, the aspiring innovator can "derisk" a project and maximize chances for successful development in an increasingly challenging regulatory and economic environment. As a specialty founded by tinkerers, with a history of disruptive innovation that has yielded countless new ways of delivering care with minimal invasiveness, lower morbidity, and lower cost, interventional radiologists are uniquely well positioned to identify unmet needs and develop novel solutions free of dogmatic convention.

Quality of Life After Bariatric Surgery.

PURPOSE OF REVIEW: The purpose of this review is to provide an introduction to quality of life (QOL) outcomes after bariatric surgery and a summary of the current evidence. RECENT FINDINGS: QOL has been emphasized in bariatric surgery since the NIH Consensus Conference statement in 1991. Initial studies were limited to 1- and 2-year follow-up. More recent findings have expanded the follow-up period up to 12 years, providing a better description of the impact on long-term QOL. Overall, there is little to no consensus regarding the definition of QOL or the ideal survey. Bariatric surgery has the greatest impact on physical QOL, and the impact on mental health remains unclear. There are some specific and less frequently reported threats to quality of life after bariatric surgery that are also discussed. Obesity has a definite impact on quality of life, even without other comorbidities, and surgery for obesity results in significant and lasting improvements in patient-reported quality of life outcomes. This conclusion is limited by a wide variety of survey instruments and absence of consensus on the definition of QOL after bariatric surgery.

Novel technologies and techniques in bariatric surgery.

Obesity has been on the rise globally and more people are now clinically obese than ever before in the US. This issue has a significant impact on both health and cost to healthcare systems. Bariatric surgery is efficacious in treatment of obesity but only in late stages of the disease, and there is a requirement for less invasive techniques/devices to treat obesity at earlier stages. Currently a number of these are either in clinical trials or have recently been approved by the Food and Drug Administration for weight loss. This review aims to give an overview of the newer technologies and techniques being used in bariatric surgery. It will also give a glimpse into future methods and those that have fallen short in recent times.