EUS-Guided Choledochoduodenostomy for Distal Malignant Biliary Obstruction Using Electrocautery-Enhanced Lumen-Apposing Metal Stents: First US, Multicenter Experience.

BACKGROUND AND AIMS: EUS-guided biliary drainage has emerged as a technique to enable endobiliary drainage in failed ERCP. A newer model, lumen-apposing metal stents (LAMS), with a cautery-enhanced delivery system became available in the USA in late 2015. This cautery-tipped version may facilitate EUS-guided choledochoduodenostomy (EUS-CD), but data using this model are lacking. METHODS: We reviewed outcomes of attempted EUS-CD using cautery-enhanced LAMS from 6, US centers. The following data were collected: patient and procedure details, technical success, adverse events, clinical success (resolution of jaundice or improvement in bilirubin > 50%), and biliary re-interventions. RESULTS: EUS-CD was attempted in 67 patients (mean age 68.8) with malignant obstruction after failed ERCP between September 2015 and April 2018. EUS-CD was technically successful in 64 (95.5%). A plastic or metal stent was inserted through the lumen of the deployed LAMS in 50 of 64 (78.1%) patients to maintain a non-perpendicular LAMS axis into the bile duct. Adverse events occurred in 4 (6.3%) and included: abdominal pain (n = 2), peritonitis that responded to antibiotics (n = 1), and bleeding requiring transfusion (n = 1). Among 40 patients with follow-up of > 4 weeks, clinical success was achieved in 100%. Biliary re-interventions for obstruction were needed in 7(17.5%), in 3 of 6 (50.0%) that underwent EUS-CD with LAMS alone versus 4 of 34 (5%) with LAMS plus an axis-orienting stent (p = 0.02). CONCLUSION: EUS-CD using LAMS with cautery-enhanced delivery systems has high technical and clinical success rates, with a low rate of adverse events. Inserting an axis-orienting stent through the lumen of the LAMS may reduce the need for biliary re-interventions.

Projection-based stabilization of interface Lagrange multipliers in immersogeometric fluid-thin structure interaction analysis, with application to heart valve modeling.

This paper discusses a method of stabilizing Lagrange multiplier fields used to couple thin immersed shell structures and surrounding fluids. The method retains essential conservation properties by stabilizing only the portion of the constraint orthogonal to a coarse multiplier space. This stabilization can easily be applied within iterative methods or semi-implicit time integrators that avoid directly solving a saddle point problem for the Lagrange multiplier field. Heart valve simulations demonstrate applicability of the proposed method to 3D unsteady simulations. An appendix sketches the relation between the proposed method and a high-order-accurate approach for simpler model problems.

Immersogeometric cardiovascular fluid-structure interaction analysis with divergence-conforming B-splines.

This paper uses a divergence-conforming B-spline fluid discretization to address the long-standing issue of poor mass conservation in immersed methods for computational fluid-structure interaction (FSI) that represent the influence of the structure as a forcing term in the fluid subproblem. We focus, in particular, on the immersogeometric method developed in our earlier work, analyze its convergence for linear model problems, then apply it to FSI analysis of heart valves, using divergence-conforming B-splines to discretize the fluid subproblem. Poor mass conservation can manifest as effective leakage of fluid through thin solid barriers. This leakage disrupts the qualitative behavior of FSI systems such as heart valves, which exist specifically to block flow. Divergence-conforming discretizations can enforce mass conservation exactly, avoiding this problem. To demonstrate the practical utility of immersogeometric FSI analysis with divergence-conforming B-splines, we use the methods described in this paper to construct and evaluate a computational model of an in vitro experiment that pumps water through an artificial valve.

Characteristic endoscopic ultrasound findings of ampullary lesions that predict the need for surgical excision or endoscopic ampullectomy.

BACKGROUND AND OBJECTIVES: The management of ampullary lesions has evolved to include endoscopic ampullectomy (EA) as a curative approach to cancers of the ampulla of Vater. With this change comes a need to risk-stratify patients at initial diagnosis. MATERIALS AND METHODS: Patients with verified ampullary lesions (N = 50) were analyzed in a case-control design. We evaluated endoscopic ultrasound (EUS) data to define characteristics that yield a high sensitivity in selecting candidates for EA. RESULTS: Using data from previously published studies yielded a sensitivity of 0.765 in appropriately identifying the 34 surgical cases. Expanding these characteristics increased the sensitivity of EUS to 0.971 in identifying surgical candidates. Additionally, of advanced disease cases, the expanded characteristics correctly identified these cases with a sensitivity of 1.0-improved over 0.708 using prior published data. CONCLUSION: EA should be strongly considered if ampullary lesions are found to fit the following characteristics after EUS evaluation: lesion size <2.5 cm, invasion ≤4 mm, pancreatic duct dilatation ≤3 mm, ≤T1 lesion, no lymph nodes present, and no ductal stent in place. Furthermore, EUS data can be used to identify all high-risk lesions. With these characteristics identified, clinicians are better able to risk-stratify patients using EUS as either appropriate for or too high-risk for endoscopic resection.

A Prospective Blinded Study Evaluating the Role of Endoscopic Ultrasound before Endoscopic Retrograde Cholangiopancreatography in the Setting of "Positive" Intraoperative Cholangiogram during Cholecystectomy.

During laparoscopic cholecystectomy, intraoperative cholangiography (IOC) is used to identify common bile duct (CBD) stones. In patients whose IOC is suspicious for stones, endoscopic retrograde cholangiopancreatography (ERCP) is the modality of choice for stone removal. However, IOC has a false positive rate of 30 to 60 per cent, and ERCP adverse events may occur in 11 per cent of patients. Endoscopic ultrasound (EUS) may serve as a noninvasive means of diagnosing suspected CBD stones. This study sought to assess the role of EUS in predicting the likelihood of choledocholithiasis at ERCP in patients found to have a positive IOC. This was a prospective blinded study of EUS before ERCP in patients with a positive IOC. Recruited subjects who underwent cholecystectomy and had an IOC with suspicion for obstruction were referred for ERCP within one month of their procedure. In patients with a positive IOC, EUS had a positive predictive value of 95 per cent in detecting choledocholithiasis. IOC with single or multiple filling defects more often correlated to the presence of CBD stones. At ERCP, choledocholithiasis was present in 65 per cent of patients who had an IOC suspicious for CBD stones. EUS should be used as a noninvasive method to correctly identify retained CBD stones in low-to-moderate risk patients with a positive IOC.

Review of current and evolving clinical indications for endoscopic ultrasound.

For the first several years after its development, endoscopic ultrasound (EUS) was primarily limited to identification of pancreatic malignancies. Since this time, the field of EUS has advanced at a tremendous speed in terms of additional clinical diagnostic and therapeutic uses. The combination of ultrasound with endoscopy provides a unique interventional modality that is a minimally invasive alternative to various surgical interventions. Given the expanding recommended indications for EUS, this article will serve to review the most common uses with supporting evidence, while also exploring innovative endeavors that may soon become common clinical practice.

Combined high-field intraoperative magnetic resonance imaging and endoscopy increase extent of resection and progression-free survival for pituitary adenomas.

PURPOSE: The clinical benefit of combined intraoperative magnetic resonance imaging (iMRI) and endoscopy for transsphenoidal pituitary adenoma resection has not been completely characterized. This study assessed the impact of microscopy, endoscopy, and/or iMRI on progression-free survival, extent of resection status (gross-, near-, and sub-total resection), and operative complications. METHODS: Retrospective analyses were performed on 446 transsphenoidal pituitary adenoma surgeries at a single institution between 1998 and 2012. Multivariate analyses were used to control for baseline characteristics, differences during extent of resection status, and progression-free survival analysis. RESULTS: Additional surgery was performed after iMRI in 56/156 cases (35.9%), which led to increased extent of resection status in 15/156 cases (9.6%). Multivariate ordinal logistic regression revealed no increase in extent of resection status following iMRI or endoscopy alone; however, combining these modalities increased extent of resection status (odds ratio 2.05, 95% CI 1.21-3.46) compared to conventional transsphenoidal microsurgery. Multivariate Cox regression revealed that reduced extent of resection status shortened progression-free survival for near- versus gross-total resection [hazard ratio (HR) 2.87, 95% CI 1.24-6.65] and sub- versus near-total resection (HR 2.10; 95% CI 1.00-4.40). Complication comparisons between microscopy, endoscopy, and iMRI revealed increased perioperative deaths for endoscopy versus microscopy (4/209 and 0/237, respectively), but this difference was non-significant considering multiple post hoc comparisons (Fisher exact, p = 0.24). CONCLUSIONS: Combined use of endoscopy and iMRI increased pituitary adenoma extent of resection status compared to conventional transsphenoidal microsurgery, and increased extent of resection status was associated with longer progression-free survival. Treatment modality combination did not significantly impact complication rate.

Endoscopic closure of persistent gastric leak and fistula following laparoscopic sleeve gastrectomy.

INTRODUCTION: Conservative management for gastric leak and fistulae after laparoscopic sleeve gastrectomy (LSG) often results in prolonged hospitalization as well as requirement of TPN or recurrent surgery (Casella et al., 2009) [1]. Endoscopically-placed stents are an additional non-invasive method, but are associated with the complication of stent migration in up to 50% of cases (Casella and co-workers, 2009) [1,4]. As other non-invasive means of treatment are absent, we believe this case demonstrates a new technique for multiple gastric leaks following LSG in patients without sepsis or peritonitis. PRESENTATION OF CASE: A patient developed a staple line gastric leak that persisted for 10 weeks following LSG despite multiple modalities of treatment. She refused to undergo stent placement, so via esophagogastroduodenoscopy (EGD), fistula margins were cauterized with argon plasma coagulation and a fibrin sealant was injected to include the surrounding area. Endoclips were placed along the fistula tracts. A repeat procedure was required. Follow up imaging confirmed resolution of gastric leak and patient did not experience additional complications. DISCUSSION: The patient was able to discontinue TPN and return to an oral diet. Both procedures were well tolerated and did not require hospitalization. CONCLUSION: Endoscopic management of multiple gastric leaks and fistulae using fibrin seal, endoclips, and cauterization appears to be a promising noninvasive form of treatment with a lower associated morbidity and shortened hospitalization.