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.

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.

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.

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.

Risk factors for readmission for early small bowel obstruction following laparoscopic Roux-en-Y gastric bypass: an MBSAQIP analysis.

BACKGROUND: Small bowel obstruction (SBO) following laparoscopic Roux-en-Y gastric bypass (LRYGB) is associated with significant morbidity. OBJECTIVES: To evaluate the rate of and risk factors for readmission for SBO within 30 days of LRYGB. SETTING: Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP)-accredited centers. METHODS: This is a retrospective study using the MBSAQIP database. A query was performed from 2015-2018 for patients who underwent LRYGB and required readmission for SBO. Those who had a reoperation, intervention, readmission, or expired from causes other than SBO were excluded. Descriptive, bivariate, and binary logistic regression analyses were performed. RESULTS: Among 184,660 patients undergoing LRYGB, 1189 (.64%) required readmission due to SBO. Among the readmission cases, 978 (82.5%) were identified as having intestinal obstruction (unspecified), 108 (9.1%) incisional hernia, and 100 (8.4%) internal hernia. Among these cases, 69% had a reoperation and 1.3% expired during the 30-day period. From a logistic regression model, parameters independently associated with an increased risk for readmission for early SBO include being female (adjusted odds ratio [AOR], 1.53) or black (AOR, 1.41) and having gastroesophageal reflux (AOR, 1.35), a history of myocardial infarction (AOR, 1.76), a history of deep vein thrombosis (AOR, 1.73), previous obesity surgery/foregut surgery (AOR, 1.79), a robotic-assisted procedure (AOR, 1.23), concurrent hiatal hernia repair (AOR, 1.66) and adhesiolysis (AOR, 1.42). CONCLUSION: The rate of readmission for early SBO following LRYGB was less than 1%. The majority of these cases required reoperation. The increased intraoperative complexity of LRYGB is associated with an increased risk of readmission due to early SBO.

Smoothed particle hydrodynamics simulation of biphasic soft tissue and its medical applications.

Modeling the coupled fluid and elastic mechanics of blood perfused soft tissues is important for medical applications. In particular, the current study aims to capture the effect of tissue swelling and the transport of blood through damaged tissue under bleeding or hemorrhaging conditions. The soft tissue is considered a dynamic poro-hyperelastic material with blood-filled voids. A biphasic formulation-effectively, a generalization of Darcy's law-is utilized, treating the phases as occupying fractions of the same volume. A Stokes-like friction force and a pressure that penalizes deviations from volume fractions summing to unity serve as the interaction force between solid and liquid phases. The resulting equations for both phases are discretized with the method of smoothed particle hydrodynamics (SPH). The solver is validated separately on each phase and demonstrates good agreement with exact solutions in test problems. Simulations of oozing, hysteresis, swelling, drying and shrinkage, and tissue fracturing and hemorrhage are shown in the paper. Graphical Abstract In the paper, a new methodology for the numerical simulation of the full dynamic response of blood-perfused soft tissues was developed.

Indications, Operative Techniques, and Outcomes for Revisional Operation Following Mini-Gastric Bypass-One Anastomosis Gastric Bypass: a Systematic Review.

In addition to being a relatively reversible and less complex operation, mini-gastric bypass-one anastomosis gastric bypass (MGB-OAGB) has demonstrated comparable weight loss and metabolic improvement rates with Roux-en-Y gastric bypass (RYGB). However, surgical strategies for managing its failures and late complications were poorly defined. This article aims to review the indications, operative techniques, and outcomes for revisional surgery following MGB-OAGB. A systematic review was performed using the PubMed database from 1997 to 2019. Of 179 included patients, 89 underwent revision to RYGB; 52 to sleeve gastrectomy (SG); 32 reversal to original anatomy; and 6 underwent partial revision with gastro-gastrostomy alone. Most common indications were severe malnutrition, chronic bile reflux, intractable marginal ulcerations, and insufficient weight loss. Postoperative complication rates ranged from 5 to 35%.

Short- and intermediate-term clinical outcome comparison between laparoscopic and robotic-assisted median arcuate ligament release.

While laparoscopic median arcuate ligament (MAL) release remains the most common approach, robotic-assisted MAL release has been increasingly performed by several institutions. This study aims to compare surgical outcomes between laparoscopic and robotic-assisted MAL release. This is a retrospective study of patients undergoing laparoscopic and robotic-assisted MAL release in a teaching hospital from January 1999 to December 2018. Intraoperative and postoperative outcomes as well as short- and intermediate-term clinical outcomes were compared between the two groups. A total of 16 laparoscopic and 18 robotic cases were included. Demographics and baseline characteristics were similar between the two comparison groups. Median operative time was shorter in the robotic group [179.5 (IQR 127.3-225) vs. 106 (IQR 80.8-122.8) minutes; p < 0.001]. The rates of conversion to open operation were similar in both groups (6.3% vs. 5.6%, p = 0.99). Conversions to laparotomy were performed due to bleeding and extensive adhesions in one laparoscopic case and due to technical difficulties in a patient with narrow body habitus in the robotic group. Postoperative complication rates were similar (12.5% vs. 16.7%, p = 0.99), all in grade I and II. Complete pain resolution rates (37.5% vs. 44.4%, p = 0.93), symptom recurrence rates (37.5% vs. 27.8%, p = 0.93), and overall clinical improvement at last follow-up (87.5% vs. 77.8%, p = 0.66) were not statistically different. Both laparoscopic and robotic-assisted MAL release offer similar short- and intermediate-term clinical outcomes. A shortened operative time may be achieved by incorporating the robot platform.

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.

A robotic system for telementoring and training in laparoscopic surgery.

A laparoscopic surgical training system, the LapaRobot, is introduced. The system is composed of an expert station and a trainee station connected through the Internet. Embedded actuators allow the trainee station to be driven by an expert surgeon so that a trainee learns proper technique through physical feedback. The surgical-tool trajectory and video feed can be recorded and later "played back" to a trainee to hone operative skills through guided repetition without the need for expert supervision. The system is designed to create a high-fidelity approximation of the intracorporeal workspace, incorporate commercially available surgical instruments, and provide a wealth of high-resolution data for quantitative analysis and feedback. Experimental evaluation demonstrated a 55% improvement in surgical performance with use of our system. In this paper, we introduce the details of the design and fabrication of the LapaRobot, illustrate the mechatronics and software-control schemes, and evaluate the system in a study.

Multi-Modal Haptic Feedback for Grip Force Reduction in Robotic Surgery.

Minimally invasive robotic surgery allows for many advantages over traditional surgical procedures, but the loss of force feedback combined with a potential for strong grasping forces can result in excessive tissue damage. Single modality haptic feedback systems have been designed and tested in an attempt to diminish grasping forces, but the results still fall short of natural performance. A multi-modal pneumatic feedback system was designed to allow for tactile, kinesthetic, and vibrotactile feedback, with the aims of more closely imitating natural touch and further improving the effectiveness of HFS in robotic surgical applications and tasks such as tissue grasping and manipulation. Testing of the multi-modal system yielded very promising results with an average force reduction of nearly 50% between the no feedback and hybrid (tactile and kinesthetic) trials (p < 1.0E-16). The multi-modal system demonstrated an increased reduction over single modality feedback solutions and indicated that the system can help users achieve average grip forces closer to those normally possible with the human hand.

Characterization of perfused and sectioned liver tissue in a full indentation cycle using a visco-hyperelastic model.

Realistic modeling of biologic material is required for optimizing fidelity in computer-aided surgical training and assistance systems. The modeling of liver tissue has remained challenging due to its nonlinear viscoelastic properties and high hysteresis of the stress-strain relation. While prior studies have described the behavior of liver tissue during the loading status (in elongation, compression, or indentation tests) or unloading status (in stress relaxation or creep tests), a hysteresis curve with both loading and unloading processes was incompletely defined. We seek to use a single material model to characterize the mechanical properties of liver tissue in a full indentation cycle ex vivo perfused and then sectioned. Based on measurements taken from ex-vivo perfused porcine livers, we converted force-displacement curves to stress-strain curves and developed a visco-hyperelastic constitutive model to characterize the liver's mechanical behavior at different locations under various rates of indentation (1, 2, 5, 10, and 20 mm/s). The proposed model is a mixed visco-hyperelastic model with up to 6 coefficients. The normalized root mean square standard deviations of fitted curves are less than 5% and 10% in low (<0.05) and high strain (>0.3) conditions respectively.

Suture Breakage Warning System for Robotic Surgery.

As robotic surgery has increased in popularity, the lack of haptic feedback has become a growing issue due to the application of excessive forces that may lead to clinical problems such as intraoperative and postoperative suture breakage. Previous suture breakage warning systems have largely depended on visual and/or auditory feedback modalities, which have been shown to increase cognitive load and reduce operator performance. This work catalogues a new sensing technology and haptic feedback system (HFS) that can reduce instances of suture failure without negatively impacting performance outcomes including knot quality. Suture breakage is common in knot-tying as the pulling motion introduces prominent shear forces. A shear sensor mountable on the da Vinci robotic surgical system's Cadiere grasper detects forces that correlate to the suture's internal tension. HFS then provides vibration feedback to the operator as forces near a particular material's failure load. To validate the system, subjects tightened a total of four knots, two with the Haptic Feedback System (HFS) and two without feedback. The number of suture breakages were recorded and knot fidelity was evaluated by measuring knot slippage. Results showed that instances of suture failure were significantly reduced when HFS was enabled (p = 0.0078). Notably, knots tied with HFS also showed improved quality compared to those tied without feedback (p = 0.010). The results highlight the value of HFS in improving robotic procedure outcomes by reducing instances of suture failures, producing better knots, and reducing the need for corrective measures.

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.

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.

A regulated multiscale closed-loop cardiovascular model, with applications to hemorrhage and hypertension.

A computational tool is developed for simulating the dynamic response of the human cardiovascular system to various stressors and injuries. The tool couples 0-dimensional models of the heart, pulmonary vasculature, and peripheral vasculature to 1-dimensional models of the major systemic arteries. To simulate autonomic response, this multiscale circulatory model is integrated with a feedback model of the baroreflex, allowing control of heart rate, cardiac contractility, and peripheral impedance. The performance of the tool is demonstrated in 2 scenarios: neurogenic hypertension by sustained stimulation of the sympathetic nervous system and an acute 10% hemorrhage from the left femoral artery.

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.

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.