Comparison of Eastern and Western patients undergoing bariatric surgery at two US and Korean institutions: a retrospective analysis of differing bariatric patient populations.

BACKGROUND: Currently, there are differences in both demographics and indications for bariatric surgery between Eastern and Western countries. We compared postoperative outcomes between Korean and American bariatric programs in order to assess how bariatric surgery differently affects these populations. METHODS: We enrolled 540 patients who underwent bariatric surgery at University of California, Los Angeles (UCLA) and 85 patients who underwent surgery at Kosin University Gospel Hospital (KUGH) between January 2019 and December 2020. We compared demographics, complications, weight loss, and metabolic parameters between these groups. RESULTS: There was a difference in age between the UCLA and KUGH patient groups (44.3 years vs 37.6 years, P < 0.01). Frequencies of T2DM and OSA were also different (4.2% vs 50.6%, 34.1% vs 85.9% P < 0.01. Length of hospital stay varied (1.55 days vs 6.68 days, P < 0.01), but there was no difference in operating time and complications. There was no difference in percent of excess weight loss between the two groups at 6 months (29.7 vs 33.8, P = 0.13). Hepatic steatosis index (HSI) was higher in the UCLA group both before (54.2 vs 51.5, P < 0.01) and after (44.4 vs 40.0, P = 0.02) surgery. LSG was the most frequently performed operation, and robotic surgery and revisions were performed only in the UCLA program. CONCLUSION: There were differences in age, BMI, length of stay, and choice of operation between Korean and American bariatric patients. Also, there were differences in the degree of fatty liver disease using HSI and liver enzymes before and after surgery. There was no significant differences in operation time and complications. These findings suggest differences in bariatric practices and reactions to bariatric surgery in Eastern and Western settings.

Incidence and risk factors for early gastrojejunostomy anastomotic stricture requiring endoscopic intervention following laparoscopic Roux-en-Y gastric bypass: a MBSAQIP analysis.

BACKGROUND: Gastrojejunostomy (GJ) stricture is one of the most commonly recognized complications following laparoscopic Roux-en-Y gastric bypass (LRYGB). The risks involving the formation of early GJ stomal stenosis are largely unknown. The aims of this study are to evaluate the rate and risk factors associated with GJ stricture in patients requiring esophagogastroduodenoscopy (EGD) within 30 days after LRYGB. METHODS: This is a retrospective study of patients who underwent EGD for GJ stricture following LRYGB. Data were retrieved from MBSAQIP database from 2015 to 2018. Descriptive, bivariate, and logistic regression analyses were performed. Those who had reoperation, readmission, and intervention for other indications rather than GJ stricture were excluded from the risk factor analysis. RESULTS: 760,076 patients underwent bariatric surgery. Of these, 184,660 (24.3%) underwent LRYGB and 875 had GJ stricture within 30 days postoperatively. The overall incidence of early GJ stricture after LRYGB was 4.7 per 1000 person-years. The incidence decreased from 6.2 to 3.4 per 1000 person-years during the 4-year period. 85% of patients with GJ stricture required therapeutic intervention. Median (IQR) day to the first endoscopic intervention was 25 (21-28) days. The overall 30-day readmission rate was 40%. 30-day reoperation rate due to GJ stricture was 5.6%. No 30-day mortality occurred. Factors independently associated with an increased risk for early GJ stricture include concurrent hiatal hernia repair (Adjusted Odds Ratio-AOR 1.8, 95% CI 1.5-2.2), revision case (AOR 1.4, 95% CI 1.1-1.6), African American (AOR 1.4, 95% CI 1.2-1.7), gastroesophageal reflux disease-GERD (AOR 1.4, 95% CI 1.2-1.5), drain placement (AOR 1.3, 95% CI1.1-1.4), and routine postoperative swallow study (AOR 1.3, 95% CI 1.1-1.50). CONCLUSION: The incidence of early GJ stricture following LRYGB decreased at MBSAQIP-accredited centers over the review period. Patients having additional manipulation at or around GJ were at risk of developing early GJ stricture after LRYGB.

Factors Associated with Symptomology of Celiac Artery Compression and Outcomes following Median Arcuate Ligament Release.

BACKGROUND: This study aims to identify potential risk factors for becoming symptomatic in patients with radiographic celiac artery compression (CAC) as well as prognostic factors for patients with median arcuate ligament syndrome (MALS) who underwent surgical ligament release. METHODS: This is a retrospective cohort study of patients with findings of CAC on computed tomography or magnetic resonance angiography (CT/MRA) who were asymptomatic and who were diagnosed with MALS at a single university hospital between January 2001 and 2018. RESULTS: Following a review of 1,330 CT/MRA reports, a total of 109 patients were identified as having radiographically apparent CAC. Among these, 48 (44.0%) patients were symptomatic. Univariate comparison between those with and without symptoms showed that symptomatic patients were more commonly younger than 30 years old [17/48 (35.4%) vs. 8/61 (13.1%), P = 0.006], had a history of prior abdominal surgery [25/48 (52.1%) vs. 18/61 (29.5%), P = 0.017], and had high-grade stenosis [32/43 (74.4%) vs. 25/61 (41.0%), P = 0.001]. Among 41 included patients who underwent surgical release of the median arcuate ligament including open, laparoscopic, and robotic approaches, 82.9% reported overall clinical improvement, 5/41 (12.2%) reported persistent pain, and 13/36 (36.0%) experienced pain recurrence. The only identified risk factor associated with symptom recurrence was American Society of Anesthesiologists class III [7/13 (53.8%) vs. 4/23 (17.4%), P = 0.029]. CONCLUSIONS: The severity of stenosis and prior abdominal surgery both contributed to symptom development in patients with radiographically apparent CAC from the median arcuate ligament.

Artificial palpation in robotic surgery using haptic feedback.

BACKGROUND: The loss of tactile feedback in minimally invasive robotic surgery remains a major challenge to the expanding field. With visual cue compensation alone, tissue characterization via palpation proves to be immensely difficult. This work evaluates a bimodal vibrotactile system as a means of conveying applied forces to simulate haptic feedback in two sets of studies simulating an artificial palpation task using the da Vinci surgical robot. METHODS: Subjects in the first study were tasked with localizing an embedded vessel in a soft tissue phantom using a single-sensor unit. In the second study, subjects localized tumor-like structures using a three-sensor array. In both sets of studies, subjects completed the task under three trial conditions: no feedback, normal force tactile feedback, and hybrid vibrotactile feedback. Recordings of correct localization, incorrect localization, and time-to-completion were used to evaluate performance outcomes. RESULTS: With the addition of vibrotactile and pneumatic feedback, significant improvements in the percentage of correct localization attempts were detected (p = 0.0001 and p = 0.0459, respectively) during the first experiment with phantom vessels. Similarly, significant improvements in correct localization were found with the addition of vibrotactile (p = 2.57E-5) and pneumatic significance (p = 8.54E-5) were observed in the second experiment involving tumor phantoms. CONCLUSIONS: This work demonstrates not only the superior benefits of a multi-modal feedback over traditional single-modality feedback, but also the effectiveness of vibration in providing haptic feedback to artificial palpation systems.

Diffusion of robotic-assisted laparoscopic technology across specialties: a national study from 2008 to 2013.

INTRODUCTION: Robotic-assisted procedures were frequently found to have similar outcomes and indications to their laparoscopic counterparts, yet significant variation existed in the acceptance of robotic-assisted technology between surgical specialties and procedures. We performed a retrospective cohort study investigating factors associated with the adoption of robotic assistance across the United States from 2008 to 2013. METHODS: Using the Nationwide Inpatient Sample database, patient- and hospital-level variables were examined for differential distribution between robotic-assisted and conventional laparoscopic procedures. Multilevel logistic regression models were constructed to identify independent factors associated with robotic adoption. Furthermore, cases were stratified by procedure and specialty before being ranked according to proportion of robotic-assistance adoption. Correlation was examined between robotic-assistance adoption and relative outcome in comparison with conventional laparoscopic procedures. RESULTS: The national robotic case volume doubled over the five-year period while a gradual decline in laparoscopic case volume was observed, resulting in an increase in the proportion of procedures performed with robotic assistance from 6.8 to 17%. Patients receiving robotic procedures were more likely to be younger, males, white, privately insured, more affluent, and with less comorbidities. These differences have been decreasing over the study period. The three specialties with the highest proportion of robotic-assisted laparoscopic procedures were urology (34.1%), gynecology (11.0%), and endocrine surgery (9.4%). However, no significant association existed between the frequency of robotic-assistance usage and relative outcome statistics such as mortality, charge, or length of stay. CONCLUSION: The variation in robotic-assistance adoption between specialties and procedures could not be attributable to clinical outcomes alone. Cultural readiness toward adopting new technology within specialty and target anatomic areas appear to be major determining factors influencing its adoption.

Robotic-assisted laparoscopic median arcuate ligament release: 7-year experience from a single tertiary care center.

BACKGROUND: Despite previous reports of robotic-assisted laparoscopic release for median arcuate ligament syndrome (MALS), the safety and efficacy profile of this approach has been difficult to establish due to the rarity of this diagnostic entity. We aim to present our experience from a tertiary minimally invasive surgery referral center. METHODS: A case series was performed whereby all patients who underwent robotic-assisted MAL release from July 2010 to July 2017 at our institution were included. Diagnosis of MALS was made based on consideration of symptom presentation, celiac artery duplex ultrasound, and corresponding findings on Computed Tomography (CT) or Magnetic Resonance Angiography (MRA). Outcomes up until the most recent clinic follow-up were reviewed. RESULTS: A total of 13 patients underwent robotic-assisted MAL release. Patients' age ranged from 16 to 71 years (mean 38 years) and consisted primarily of females (76.9%). Most common presenting symptoms included postprandial pain (76.9%), weight loss (76.9%), nausea and vomiting (76.9%). Mean symptom duration was 3 years (range 1-10 years). No intraoperative complications. None required conversion to open surgery. One case required a conversion back to laparoscopy due to anatomical complexity. The mean operative time for successfully completed robotic cases was 94.6 min (range 52-120 min), and for all cases including converted case was 103.5 min (52-210 min). Mean follow-up duration was 19.7 months (range 1-77 months). During subsequent follow-up, a 30-day readmission rate of 23.1% was observed. All but one of the patients experienced prompt symptom improvement. Four patients had symptom recurrence during follow-up. CONCLUSIONS: Our experience demonstrates that the robotic-assisted approach to MAL release may be safe and efficacious in selected patients. Prospective comparative studies are required to further evaluate its outcomes against conventional laparoscopic approach, the current gold standard.

Surgically Induced Changes in Gut Microbiome and Hedonic Eating as Related to Weight Loss: Preliminary Findings in Obese Women Undergoing Bariatric Surgery.

OBJECTIVE: Weight loss surgery results in significant changes in the anatomy, function, and intraluminal environment of the gastrointestinal tract affecting the gut microbiome. Although bariatric surgery results in sustained weight loss, decreased appetite, and hedonic eating, it is unknown whether the surgery-induced alterations in gut microbiota play a role in the observed changes in hedonic eating. We explored the following hypotheses: (1) laparoscopic sleeve gastrectomy (LSG) results in changes in gut microbial composition; (2) alterations in gut microbiota are related to weight loss; (3) alterations in gut microbiome are associated with changes in appetite and hedonic eating. METHODS: Eight obese women underwent LSG. Their body mass index, body fat mass, food intake, hunger, hedonic eating scores, and stool samples were obtained at baseline and 1-month postsurgery. 16S ribosomal RNA gene sequencing was performed on stool samples. DESeq2 changes in microbial abundance. Multilevel-sparse partial least squares discriminant analysis was applied to genus-level abundance for discriminative microbial signatures. RESULTS: LSG resulted in significant reductions in body mass index, food intake, and hedonic eating. A microbial signature composed of five bacterial genera discriminated between pre- and postsurgery status. Several bacterial genera were significantly associated with weight loss (Bilophila, q = 3E-05; Faecalibacterium q = 4E-05), lower appetite (Enterococcus, q = 3E-05), and reduced hedonic eating (Akkermansia, q = .037) after surgery. CONCLUSIONS: In this preliminary analysis, changes in gut microbial abundance discriminated between pre- and postoperative status. Alterations in gut microbiome were significantly associated with weight loss and with reduced hedonic eating after surgery; however, a larger sample is needed to confirm these findings.

Visual-perceptual mismatch in robotic surgery.

BACKGROUND: The principal objective of the experiment was to analyze the effects of the clutch operation of robotic surgical systems on the performance of the operator. The relative coordinate system introduced by the clutch operation can introduce a visual-perceptual mismatch which can potentially have negative impact on a surgeon's performance. We also assess the impact of the introduction of additional tactile sensory information on reducing the impact of visual-perceptual mismatch on the performance of the operator. METHODS: We asked 45 novice subjects to complete peg transfers using the da Vinci IS 1200 system with grasper-mounted, normal force sensors. The task involves picking up a peg with one of the robotic arms, passing it to the other arm, and then placing it on the opposite side of the view. Subjects were divided into three groups: aligned group (no mismatch), the misaligned group (10 cm z axis mismatch), and the haptics-misaligned group (haptic feedback and z axis mismatch). Each subject performed the task five times, during which the grip force, time of completion, and number of faults were recorded. RESULTS: Compared to the subjects that performed the tasks using a properly aligned controller/arm configuration, subjects with a single-axis misalignment showed significantly more peg drops (p = 0.011) and longer time to completion (p < 0.001). Additionally, it was observed that addition of tactile feedback helps reduce the negative effects of visual-perceptual mismatch in some cases. Grip force data recorded from grasper-mounted sensors showed no difference between the different groups. CONCLUSIONS: The visual-perceptual mismatch created by the misalignment of the robotic controls relative to the robotic arms has a negative impact on the operator of a robotic surgical system. Introduction of other sensory information and haptic feedback systems can help in potentially reducing this effect.

Tensile strength and failure load of sutures for robotic surgery.

BACKGROUND: Robotic surgical platforms have seen increased use among minimally invasive gastrointestinal surgeons (von Fraunhofer et al. in J Biomed Mater Res 19(5):595-600, 1985. doi: 10.1002/jbm.820190511 ). However, these systems still suffer from lack of haptic feedback, which results in exertion of excessive force, often leading to suture failures (Barbash et al. in Ann Surg 259(1):1-6, 2014. doi: 10.1097/SLA.0b013e3182a5c8b8 ). This work catalogs tensile strength and failure load among commonly used sutures in an effort to prevent robotic surgical consoles from exceeding identified thresholds. Trials were thus conducted on common sutures varying in material type, gauge size, rate of pulling force, and method of applied force. METHODS: Polydioxanone, Silk, Vicryl, and Prolene, gauges 5-0 to 1-0, were pulled till failure using a commercial mechanical testing system. 2-0 and 3-0 sutures were further tested for the effect of pull rate on failure load at rates of 50, 200, and 400 mm/min. 3-0 sutures were also pulled till failure using a da Vinci robotic surgical system in unlooped, looped, and at the needle body arrangements. RESULTS: Generally, Vicryl and PDS sutures had the highest mechanical strength (47-179 kN/cm2), while Silk had the lowest (40-106 kN/cm2). Larger diameter sutures withstand higher total force, but finer gauges consistently show higher force per unit area. The difference between material types becomes increasingly significant as the diameters decrease. Comparisons of identical suture materials and gauges show 27-50% improvement in the tensile strength over data obtained in 1985 (Ballantyne in Surg Endosc Other Interv Tech 16(10):1389-1402, 2002. doi: 10.1007/s00464-001-8283-7 ). No significant differences were observed when sutures were pulled at different rates. Reduction in suture strength appeared to be strongly affected by the technique used to manipulate the suture. CONCLUSIONS: Availability of suture tensile strength and failure load data will help define software safety protocols for alerting a surgeon prior to suture failure during robotic surgery. Awareness of suture strength weakening with direct instrument manipulation may lead to the development of better techniques to further reduce intraoperative suture breakage.

Evaluating tactile feedback in robotic surgery for potential clinical application using an animal model.

INTRODUCTION: The aims of this study were to evaluate (1) grasping forces with the application of a tactile feedback system in vivo and (2) the incidence of tissue damage incurred during robotic tissue manipulation. Robotic-assisted minimally invasive surgery has been shown to be beneficial in a variety of surgical specialties, particularly radical prostatectomy. This innovative surgical tool offers advantages over traditional laparoscopic techniques, such as improved wrist-like maneuverability, stereoscopic video displays, and scaling of surgical gestures to increase precision. A widely cited disadvantage associated with robotic systems is the absence of tactile feedback. METHODS AND PROCEDURE: Nineteen subjects were categorized into two groups: 5 experts (six or more robotic cases) and 14 novices (five cases or less). The subjects used the da Vinci with integrated tactile feedback to run porcine bowel in the following conditions: (T1: deactivated tactile feedback; T2: activated tactile feedback; and T3: deactivated tactile feedback). The grasping force, incidence of tissue damage, and the correlation of grasping force and tissue damage were analyzed. Tissue damage was evaluated both grossly and histologically by a pathologist blinded to the sample. RESULTS: Tactile feedback resulted in significantly decreased grasping forces for both experts and novices (P < 0.001 in both conditions). The overall incidence of tissue damage was significantly decreased in all subjects (P < 0.001). A statistically significant correlation was found between grasping forces and incidence of tissue damage (P = 0.008). The decreased forces and tissue damage were retained through the third trial when the system was deactivated (P > 0.05 in all subjects). CONCLUSION: The in vivo application of integrated tactile feedback in the robotic system demonstrates significantly reduced grasping forces, resulting in significantly less tissue damage. This tactile feedback system may improve surgical outcomes and broaden the use of robotic-assisted minimally invasive surgery.

Intraoperative Laparoscopic Near-Infrared Fluorescence Cholangiography to Facilitate Anatomical Identification: When to Give Indocyanine Green and How Much.

Recent technological advances have enabled real-time near-infrared fluorescence cholangiography (NIRFC) with indocyanine green (ICG). Whereas several studies have shown its feasibility, dosing and timing for practical use have not been optimized. We undertook a prospective study with systematic variation of dosing and timing from injection of ICG to visualization. Adult patients undergoing laparoscopic biliary and hepatic operations were enrolled. Intravenous ICG (0.02-0.25 mg/kg) was administered at times ranging from 10 to 180 minutes prior to planned visualization. The porta hepatis was examined using a dedicated laparoscopic system equipped to detect NIRFC. Quantitative analysis of intraoperative fluorescence was performed using a scoring system to identify biliary structures. A total of 37 patients were enrolled. Visualization of the extrahepatic biliary tract improved with increasing doses of ICG, with qualitative scores improving from 1.9 ± 1.2 (out of 5) with a 0.02-mg/kg dose to 3.4 ± 1.3 with a 0.25-mg/kg dose (P < .05 for 0.02 vs 0.25 mg/kg). Visualization was also significantly better with increased time after ICG administration (1.1 ± 0.3 for 10 minutes vs 3.4 ± 1.1 for 45 minutes, P < .01). Similarly, quantitative measures also improved with both dose and time. There were no complications from the administration of ICG. These results suggest that a dose of 0.25 mg/kg administered at least 45 minutes prior to visualization facilitates intraoperative anatomical identification. The dosage and timing of administration of ICG prior to intraoperative visualization are within a range where it can be administered in a practical, safe, and effective manner to allow intraoperative identification of extrahepatic biliary anatomy using NIRFC.

Generalizability of Randomized Clinical Trial Outcomes for Diabetes Control Resulting From Bariatric Surgery.

Objective: To assess the external validity of randomized controlled trials (RCTs) of bariatric surgical treatment on diabetes control. Background: Multisite RCTs provide the strongest evidence supporting clinical treatments and have the greatest internal validity. However, characteristics of trial participants may not be representative of patients receiving treatment in the real world. There is a need to assess how the results of RCTs generalize to all contemporary patient populations undergoing treatments. Methods: All patients undergoing sleeve gastrectomy at University of California Los Angeles (UCLA) between January 8, 2018 and May 19, 2023 had their baseline characteristics, weight change, and diabetes control compared with those enrolled in the surgical treatment and medications potentially eradicate diabetes efficiently (STAMPEDE) and diabetes surgery study (DSS) RCTs of bariatric surgery's effect on diabetes control. Weight loss and diabetes control were compared between UCLA patients who did and did not fit the entry criteria for these RCTs. Results: Only 65 (17%) of 387 patients with diabetes fulfilled the eligibility criteria for STAMPEDE, and 29 (7.5%) fulfilled the criteria for DSS due to being older, having higher body mass index, and lower HbA1c. UCLA patients experienced slightly less weight loss than patients in the RCTs but had similar diabetes control. The 313 (81%) patients not eligible for study entry into either RCT had similar long-term diabetes control as those who were eligible for the RCTs. Conclusions: Even though only a very small proportion of patients undergoing bariatric surgery met the eligibility criteria for the 2 major RCTs, most patients in this contemporary cohort had similar outcomes. Diabetes outcomes from STAMPEDE and DSS generalize to most patients undergoing bariatric surgery for diabetes control.

The role of tactile feedback in grip force during laparoscopic training tasks.

BACKGROUND: Laparoscopic minimally invasive surgery has revolutionized surgical care by reducing trauma to the patient, thereby decreasing the need for medication and shortening recovery times. During open procedures, surgeons can directly feel tissue characteristics. However, in laparoscopic surgery, tactile feedback during grip is attenuated and limited to the resistance felt in the tool handle. Excessive grip force during laparoscopic surgery can lead to tissue damage. Providing additional supplementary tactile feedback may allow subjects to have better control of grip force and identification of tissue characteristics, potentially decreasing the learning curve associated with complex minimally invasive techniques. METHODS: A tactile feedback system has been developed and integrated into a modified laparoscopic grasper that allows forces applied at the grasper tips to be felt by the surgeon's hands. In this study, 15 subjects (11 novices, 4 experts) were asked to perform single-handed peg transfers using these laparoscopic graspers in three trials (feedback OFF, ON, OFF). Peak and average grip forces (newtons) during each grip event were measured and compared using a Wilcoxon ranked test in which each subject served as his or her own control. RESULTS: After activating the tactile feedback system, the novice subject population showed significant decreases in grip force (p < 0.003). When the system was deactivated for the third trial, there were significant increases in grip force (p < 0.003). Expert subjects showed no significant improvements with the addition of tactile feedback (p > 0.05 in all cases). CONCLUSION: Supplementary tactile feedback helped novice subjects reduce grip force during the laparoscopic training task but did not offer improvements for the four expert subjects. This indicates that tactile feedback may be beneficial for laparoscopic training but has limited long-term use in the nonrobotic setting.

Microbial changes from bariatric surgery alters glucose-dependent insulinotropic polypeptide and prevents fatty liver disease.

Bariatric surgery remains a potent therapy for nonalcoholic fatty liver disease (NAFLD), but its inherent risk and eligibility requirement limit its adoption. Therefore, understanding how bariatric surgery improves NAFLD is paramount to developing novel therapeutics. Here, we show that the microbiome changes induced by sleeve gastrectomy (SG) reduce glucose-dependent insulinotropic polypeptide (GIP) signaling and confer resistance against diet-induced obesity (DIO) and NAFLD. We examined a cohort of NALFD patients undergoing SG and evaluated their microbiome, serum metabolites, and GI hormones. We observed significant changes in Bacteroides, lipid-related metabolites, and reduction in GIP. To examine if the changes in the microbiome were causally related to NAFLD, we performed fecal microbial transplants in antibiotic-treated mice from patients before and after their surgery who had significant weight loss and improvement of their NAFLD. Mice transplanted with the microbiome of patients after bariatric surgery were more resistant to DIO and NAFLD development compared to mice transplanted with the microbiome of patients before surgery. This resistance to DIO and NAFLD was also associated with a reduction in GIP levels in mice with post-bariatric microbiome. We further show that the reduction in GIP was related to higher levels of Akkermansia and differing levels of indolepropionate, bacteria-derived tryptophan-related metabolite. Overall, this is one of the few studies showing that GIP signaling is altered by the gut microbiome, and it supports that the positive effect of bariatric surgery on NAFLD is in part due to microbiome changes.

Open and laparoscopic treatment of median arcuate ligament syndrome.

BACKGROUND: Median arcuate ligament syndrome (MALS) is a syndrome associated with chronic abdominal pain and radiographic evidence of celiac artery compression. We compared the evidence for both open and laparoscopic treatment of patients with MALS. METHODS: We reviewed the English-language literature between 1963 and 2012. Presenting symptoms, clinical improvement, operative details, and intraoperative and postoperative complications were noted. RESULTS: A total of 400 patients underwent surgical (open and laparoscopic) treatment for MALS. Three hundred thirty-nine patients reported immediate postoperative symptom relief (85%). Late recurrence of symptoms was reported in 19 patients in the open group (6.8%) and seven patients in the laparoscopic group (5.7%). Eleven out of 121 patients (9.1%) in the laparoscopic group required open conversion secondary to bleeding. CONCLUSIONS: The available evidence demonstrates that both laparoscopic and open ligament release, celiac ganglionectomy, and celiac artery revascularization may provide sustained symptom relief in the majority of patients diagnosed with MALS. The role of arterial revascularization following ligament release remains unclear. The rate of open conversion with the laparoscopic approach is high, but no perioperative deaths have been reported.

A Novel Sensor for Tissue Mechanical Property Detection During Robotic Surgery.

Haptic feedback relays important tissue mechanical properties to surgeons during open surgery. However, this information is lost during Robot-assisted Minimally Invasive Surgery (RMIS). Here we present a proof-of-concept for a novel instrument-integrated sensor that uses fiber Bragg grating (FBG) arrays to identify tissues based on mechanical properties. Subjects were tasked with sorting tissue phantoms based on hardness. When using a conventional surgical robot, the average error for novices (N=5) and the expert user was 22.5% and 12.5% respectively. This reduced to 2.5% and 0% when sorting with direct palpation by hand. In contrast, the senorized instrument with automated analysis was able to perform the task without any error across all trials. Clinical Relevance - The proposed sensor has the potential of identifying different tissues based on mechanical properties and thus characterize tumors and other relevant structures. It is envisaged that this will improve decision making process during RMIS and also provide useful sensory information for autonomous surgery.

Reducing retraction forces with tactile feedback during robotic total mesorectal excision in a porcine model.

Excessive tissue-instrument interaction forces during robotic surgery have the potential for causing iatrogenic tissue damages. The current in vivo study seeks to assess whether tactile feedback could reduce intraoperative tissue-instrument interaction forces during robotic-assisted total mesorectal excision. Five subjects, including three experts and two novices, used the da Vinci robot to perform total mesorectum excision in four pigs. The grip force in the left arm, used for retraction, and the pushing force in the right arm, used for blunt pelvic dissection around the rectum, were recorded. Tissue-instrument interaction forces were compared between trials done with and without tactile feedback. The mean force exerted on the tissue was consistently higher in the retracting arm than the dissecting arm (3.72 ± 1.19 vs 0.32 ± 0.36 N, p < 0.01). Tactile feedback brought about significant reductions in average retraction forces (3.69 ± 1.08 N vs 4.16 ± 1.12 N, p = 0.02), but dissection forces appeared unaffected (0.43 ± 0.42 vs 0.37 ± 0.28 N, p = 0.71). No significant differences were found between retraction and dissection forces exerted by novice and expert robotic surgeons. This in vivo animal study demonstrated the efficacy of tactile feedback in reducing retraction forces during total mesorectal excision. Further research is required to quantify the clinical impact of such force reduction.