Ultrasound-guided endoscopic surgery

A Precessing-Coin-like Rotary Actuator for Distal Endoscope Scanners: Proof-of-Concept Study

This paper presents, for the first time, a rotary actuator functionalized by an inclined disc rotor that serves as a distal optical scanner for endoscopic probes, enabling side-viewing endoscopy in luminal organs using different imaging/analytic modalities such as optical coherence tomography and Raman spectroscopy. This scanner uses a magnetic rotor designed to have a mirror surface on its backside, being electromagnetically driven to roll around the cone-shaped hollow base to create a motion just like a precessing coin. An optical probing beam directed from the probe's optic fiber is passed through the hollow cone to be incident and bent on the back mirror of the rotating inclined rotor, circulating the probing beam around the scanner for full 360° sideway imaging. This new scanner architecture removes the need for a separate prism mirror and holding mechanics to drastically simplify the scanner design and thus, potentially enhancing device miniaturization and reliability. The first proof-of-concept is developed using 3D printing and experimentally analyzed to reveal the ability of both angular stepping at 45° and high-speed rotation up to 1500 rpm within the biologically safe temperature range, a key function for multimodal imaging. Preliminary optical testing demonstrates continuous circumferential scanning of the laser beam with no blind spot caused by power leads to the actuator. The results indicate the fundamental feasibility of the developed actuator as an endoscopic distal scanner, a significant step to further development toward advancing optical endoscope technology.

Complications and management of interventional endoscopic ultrasound: A critical review

In the last decades, Endoscopic ultrasound (EUS) has rapidly grown and evolved from being mainly a diagnostic procedure, to being an interventional and therapeutic tool in several pathological clinical scenarios. With the progressive growth in technical expertise and dedicated devices, interventional endoscopic ultrasound procedures (IEUSP) have shown high rates of technical and clinical success, together with a relatively safe profile. However, the description and the standardization of different and specific types of adverse events (AEs) are still scarce in literature, and, consequently, even less the management of AEs. The aim of this study is to critical review and to describe AEs related to each of the main IEUSP, and to provide an overview on the possible management strategies of endoscopic complications. Future studies and guidelines are surely required to reach a better standardization of different AEs and their best management.

EUS-guided hepaticogastrostomy

EUS-guided biliary drainage (BD) is an option to treat obstructive jaundice when ERCP drainage fails. These procedures represent alternatives to surgery and percutaneous transhepatic BD and have been made possible through the continuous development and improvement of EUS scopes and accessories. The development of linear sectorial array EUS scopes in early 1990 brought a new approach to the diagnostic and therapeutic dimensions of echoendoscopy capabilities, opening the possibility to perform puncture over a direct ultrasonographic view. Despite the high success rate and low morbidity of BD obtained by ERCP, difficulty can arise with an ingrown stent tumor, tumor gut compression, periampullary diverticula, and anatomic variation. The EUS-guided technique requires puncture and contrast of the left biliary tree. When performed from the gastric wall, access is obtained through hepatic segment III. Diathermic dilation of the puncturing tract is performed using a 6F cystotome and a plastic or metallic stent. The technical success of hepaticogastrostomy is near 98%, and complications are present in 15%–20% of cases. The most common complications include pneumoperitoneum, bilioperitoneum, infection, and stent dysfunction. To prevent bile leakage, we used a special partially covered stent (70% covered and 30% uncovered). Over the last 15 years, the technique has typically been performed in reference centers, by groups experienced with ERCP. This seems to be a general guideline for safer execution of the procedure.

Endoscopic Ultrasound-guided Bilio-pancreatic Drainage

The echoendoscopic biliary drainage is an option to treat obstructive jaundices when endoscopic retrograde cholangiopancreatography (ERCP) drainage fails. These procedures compose alternative methods to the side of surgery and percutaneous transhepatic biliary drainage, and it was only possible by the continuous development and improvement of echoendoscopes and accessories. The development of linear sectorial array echoendoscopes in early 1990 brought a new approach to diagnostic and therapeutic dimension on echoendoscopy capabilities, opening the possibility to perform punction over direct ultrasonografic view. Despite of the high success rate and low morbidity of biliary drainage obtained by ERCP, difficulty could be found at the presence of stent tumor ingrown, tumor gut compression, periampullary diverticula and anatomic variation. The echoendoscopic technique starts performing punction and contrast of the left biliary tree. When performed from gastric wall, the access is made through hepatic segment III. From duodenum, direct common bile duct punction. Diathermic dilatation of the puncturing tract is required using a 6-Fr cystostome and a plastic or metal stent is introducted. The techincal success of hepaticogastrostomy is near 98%, and complications are present in 20%: pneumoperitoneum, choleperitoneum, infection and stent disfunction. To prevent bile leakage, we have used the 2-stent techniques. The first stent introduced was a long uncovered metal stent (8 or 10 cm) and inside this first stent a second fully covered stent of 6 cm was delivered to bridge the bile duct and the stomach. Choledochoduodenostomy overall success rate is 92%, and described complications include, in frequency order, pneumoperitoneum and focal bile peritonitis, present in 14%. By the last 10 years, the technique was especially performed in reference centers, by ERCP experienced groups, and this seems to be a general guideline to safer procedure execution. The ideal approach for pancreatic pseudocyst (PPC) puncture combines endos-copy with real time endosonography using an interventional echoendoscope. Several authors have described the use of endoscopic ultrasound (EUS) longitudinal scanners for guidance of transmural puncture and drainage procedures. The same technique could be used to access a dilated pancreatic duct in cases in which the duct cannot be drained by conventional ERCP because of complete obstruction.

Review of endoscopic ultrasound-guided fine-needle aspiration cytology

This review, based on the Hennepin County Medical Center experience and review of the literature, vastly covers the up-to-date role of endoscopic ultrasonography (EUS) and EUS-guided fine-needle aspiration (FNA) in evaluating tumorous lesions of the gastrointestinal tract and adjacent organs. Emphasis is given to the tumoral and nodal staging of esophageal, pulmonary, and pancreatic cancer. This review also discusses technical, pathological, and gastroenterologic aspects and the role of the pathologist and endosonographer in the evaluation of these lesions, as well as the corresponding FNA cytology and differential diagnosis.

Interventional endoscopic ultrasound in pancreatic diseases

During the last 15 years, endoscopic ultrasound (EUS) has become an important imaging procedure for diagnosis and management of pancreatic diseases. The clinical interest of EUS is now enhanced by interventional procedures. Noteworthy, fine-needle aspiration biopsy is one of the most important contributions of EUS, in particular for the investigation of patients with pancreatic cancer and cystic tumors. EUS-guided fine-needle aspiration appears to be a safe and reliable technique to obtain tissue from pancreatic masses with a low risk of complications. EUS became also a therapeutic procedure, especially applied for celiac plexus neurolysis, pseudocyst drainage, and pancreaticogastrostomy. Further developments are expected by improvement of needle devices such as pancreatic pseudocyst drainage kits. In the future, EUS might be also a support for local application of new treatments of pancreatic tumors, such as gene or cellular therapy products. In this review, we discuss the current clinical applications of interventional EUS and the future development for diagnosis and management of pancreatic diseases.

Subsequent resection of locally advanced pancreatic carcinoma after chemoradiotherapy

OBJECTIVES

The aim of this study was to evaluate the possibility of subsequent resection of locally advanced pancreatic adenocarcinoma after chemotherapy and external-beam radiotherapy.

PATIENTS AND METHODS

Between January 1996 and January 2001, 33 consecutive patients (18 males and 15 women, mean age 63 years) with locally advanced PA were treated with chemotherapy and concurrent external-beam radiotherapy. Radiotherapy delivered 45-50.4 Gy, in a classical manner (N=27) or on a split-course (N=6). Chemotherapy was made of 5FU by continuous infusion for all patients during 5 weeks and cisplatin at the 1st and 5th weeks (N=22). Tumor resectability was reassessed at the end of the chemoradiotherapy; surgical resection of tumour was attempted in patients whose tumor demonstrated reduction in size, and supplementary radiotherapy of 10 to 15 Gy was delivered to the others.

RESULTS

Thirty-nine percent of patients experienced grade 3 acute toxicity. WHO criteria response to chemoradiotherapy four weeks after the end of treatment were: 4 partial responders (12%), 6 minor responders (18%), 14 stable disease (42%), 9 progression (28%). Ten patients underwent exploratory laparotomy, in one case vascular encasement did not allow for tumor resection, and in another patient, there was peritoneal carcinomatosis. In the 8 remaining patients, surgical (R0) resection was possible. In one patient histological examination showed fibrosis with no residual tumour. After a median follow-up period of 40 months, median survival was 16 months (66% and 37% of survival at 1 and 2 years respectively). In operated and non-operated patients, survival rates at 24 months were 73% and 12.5% respectively. At 1 year, 80% of the patients treated with radiochemotherapy developed recurrence, metastatic recurrence in 88%. Initial laparotomy, split course radiotherapy were poor outcome factors whereas chemotherapy appears to be a favorable outcome factor.

CONCLUSION

Subsequent resection of locally advanced pancreatic adenocarcinoma is possible after chemoradiotherapy allowing for a prolonged survival in some patients.

Pancreatic carcinoma: palliative surgical and endoscopic treatment

The majority of patients with pancreatic carcinoma (hepaticojejunostomy) unfortunately will have palliative treatment and palliation of symptoms is important to improve Quality of Life. The most common symptoms that require palliation are jaundice, gastric outlet obstruction and pain. Obstructive jaundice should be treated with a biliary bypass, the optimal palliation in relatively fit patients and endoscopic stenting is preferred in patients with short survival (3-6 months). To prevent gastric outlet obstruction a prophylactic gastroenterostomy should be performed routinely during bypass surgery. Symptomatic patients after earlier stenting of the bile duct can be treated nowadays by duodenal stenting. Pain management is according to the progressive analgesic ladder but a (percutaneous) neurolytic celiac plexus block may be indicated. Currently a R1 (palliative) resection is acceptable in high volume centres but so far there is a very limited role for planned R2 palliative resections.