An anastomosis can be established between the stomach and the jejunum under the guidance of endoscopic ultrasonography (EUS) in patients with gastric outlet obstruction. A lumen-apposing metal stent (LAMS) can either be deployed directly or with balloon assistance using fluoroscopic and sonographic guidance. Although experience is limited, the preliminary data appear promising.
EUS facilitates transmural drainage of postoperative abdominal and pelvic fluid collections adjacent to the stomach, duodenum, rectum, or colonic lumen and within the reach of an echoendoscope. Both procedures are safe, with a treatment success rate greater than 90%. Adverse events are mild and can be managed conservatively in most patients.
Essentials for such procedures include a fluoroscopy unit, therapeutic echoendoscope, accessories such as 19-G needles, endoscopic retrograde cholangiopancreatography cannula or needle-knife catheters, guidewires, balloon dilators, LAMS, double-pigtail plastic stents, and biliary drainage catheters.
EUS-guided hemostasis in gastric varices can be attained with coil embolization and/or glue injection. The technique appears to be clinically effective, with promising treatment outcomes.
The use of the linear array echoendoscope has expanded the realm of therapeutic interventions to include drainage of obstructive biliary ductal system, peripancreatic fluid collections and pelvic abscesses, placement of coils or injection of sclerotic agents in varices, and more recently the creation of an anastomosis between the stomach and small bowel for palliation of gastric outlet obstruction (GOO). In this chapter, the technique and outcomes of endoscopic EUS-guided anastomosis, drainage of abdominal fluid collections and pelvic abscesses, and its role in the obliteration of gastric varices are reviewed.
Endoscopic Ultrasonography-Guided Anastomosis
Options for the treatment of GOO include open or laparoscopic gastrojejunostomy and the endoscopic placement of self-expanding metal stents (SEMS) across the luminal obstruction. Recently there have been reports of successful creation of gastroenteric anastomoses performed under endosonographic guidance. The procedure has the potential to offer long-lasting luminal patency without the risk of stent obstruction by tumor ingrowth, and it also avoids the morbidity of a surgical procedure.
EUS-guided gastroenterostomy (EUS-GE) can be performed by adopting one of three techniques: direct EUS-GE, assisted EUS GE, and EUS-guided balloon-occluded gastrojejunostomy bypass (EPASS).
Direct Endoscopic Ultrasonography-Guided Gastroenterostomy Technique
A 19-G needle is inserted transgastrically into the small-bowel loop to distend the duodenum and jejunum by infusing saline under EUS visualization.
An enterogram is then obtained by injecting a radiocontrast agent and a 0.025/0.035-inch guidewire is passed through the 19-G needle into the small bowel.
The GE tract is dilated using a 40 mm long and 4 mm wide over-the-wire dilating balloon followed by the placement of a 15- by 10-mm lumen-apposing metal stent (LAMS) ( Fig. 26.1A–F ; Video 26.1 ). It may sometimes be necessary to create a tract using a needle-knife catheter prior to performing balloon dilation. Alternatively, the electrocautery-enhanced delivery system can be used to puncture the small bowel directly for LAMS deployment.
The lumen of the LAMS may be dilated, if required, using a radial expansion balloon to create a wider opening.
The Technique of Direct Endoscopic Ultrasonography-Guided Gastroenteric Anastomosis
Assisted Endoscopic Ultrasonography-Guided Gastroenterostomy Technique
The assisted EUS-GE technique involves the passage of a retrieval/dilating balloon or ultraslim endoscope across the stricture to the duodenal-jejunal flexure to assist in the placement of a LAMS. The balloon serves as an anatomic marker for the creation of the anastomosis ( Video 26.2 ).
The retrieval or dilating balloon catheter is passed over a guidewire into the small bowel and then inflated with fluid (water mixed with contrast) while it is being positioned in the duodenum or jejunum.
The echoendoscope is then passed alongside the balloon catheter into the stomach and the fluid-filled balloon is localized by sonography.
The balloon is punctured using a 19-G needle. Bursting of the balloon indicates correct positioning of the needle tip within the small-bowel lumen.
A guidewire is advanced through the needle and a LAMS is subsequently deployed. It may be necessary to dilate the transmural tract if a nonelectrocautery-based LAMS is being deployed.
The Technique of Balloon Assisted Endoscopic Ultrasonography-Gastroenteric Anastomosis
When an ultraslim endoscope-assisted EUS-GE is performed, the small-caliber endoscope is passed perorally or through an existing gastrostomy site into the stomach and then beyond the stricture. Saline is injected through the ultraslim scope to distend the bowel lumen. The echoendoscope is then advanced into the stomach (alongside the ultraslim scope in cases where the ultraslim scope is introduced perorally). A guidewire is advanced through the needle and coiled within the bowel lumen. A biopsy forceps is then passed through the ultraslim scope to grasp the guidewire, thus providing traction in an internal rendezvous maneuver. A fistulous tract is then created for LAMS deployment. There are reports of using a nasobiliary catheter for saline and contrast injection into the duodenum-jejunum so as to facilitate fluoroscopic and sonographic visualization.
Endoscopic Ultrasonography-Guided Balloon-Occluded Gastrojejunostomy Bypass Technique
The endoscope is removed, leaving the guidewire in place. An overtube is helpful to facilitate passage of the preinflated balloon catheter to avoid looping in the fornix of the stomach as it passes through the pyloric-duodenal stenosis.
A double-balloon tube (Tokyo Medical University type, Create Medic Co., Ltd., Yokohama, Japan) is inserted perorally over the guidewire and the two balloons are placed in the duodenum and jejunum in an area adjacent to the stomach.
Both balloons are filled with saline and contrast material to anchor the small intestine in place. A sufficient quantity of saline with contrast material is introduced into the space between the two balloons to distend the small bowel lumen.
An echoendoscope is advanced to the stomach to identify the distended duodenum or jejunum.
EUS-guided balloon-occluded gastrojejunostomy bypass (EPASS) can then be undertaken by one of two techniques, namely the “free style” or “standard” technique. The former is performed using a direct electrocautery-enhanced tip delivery system insertion without needle puncture, whereas the latter involves placement of the LAMS over a guidewire, as described previously.
Endoscopic Ultrasonography-Guided Balloon-Occluded Gastrojejunostomy Bypass Technique
Technical and Treatment Outcomes
Three case series have reported an overall technical success rate of approximately 90% regardless of the technique adopted ( Table 26.1 ). In the EPASS procedure, the success rate of the freestyle technique was higher than that of the standard technique (100% vs. 82%). Treatment success was observed in almost all cases where the LAMS was successfully placed. Although there was no mortality, adverse events such as peritonitis or bleeding were encountered in several patients, although none were life-threatening. One failed case of balloon-assisted EUS-GE required conversion to a laparoscopic gastrojejunostomy. In two cases of stent maldeployment using the EPASS procedure, both patients responded well to conservative treatment measures.
|Author (Year)||No. of Cases||Technique||Type of Balloon||Study Design||Single/Multicenter||Technical Success||Clinical Success a||Adverse Event||Convert to Surgery|
|Khashab et al. (2015)||10||D, 1/B, 9||RB, 4/DB, 5||R||Multicenter||90%||90%||None||1 b|
|Itoi et al. (2016)||20||EPASS 1-step, 9; 2-step, 11||Double balloon enteric tube||P||Single||1-step, 100%; 2-step, 82%||90%||Pneumoperitoneum 1||None|
|Tyberg et al. (2016)||26||D, 3/NOTES, 2/B, 13/USS, 5/NBD, 2||NA||R||Multicenter||92%||85%||Peritonitis 1||1 b|
|Bleeding 1, Pain 1|
Limitations of the EUS-guided gastroenteric anastomosis include the following: (1) If the most proximal enteric lumen is located farther from stomach, EUS-guided anastomosis may not be appropriate unless alternate lumen-apposing devices such as T-tags are used and (2) the procedure cannot be performed safely when LAMS are not available due to the lack of adhesion between the stomach and the enteric tract.
Endoscopic Ultrasonography-Guided Drainage of Abdominopelvic Fluid Collections
Abdominal and/or pelvic abscesses can occur postoperatively after pancreatic, liver, and bariatric surgery or in patients with medical conditions such as Crohn disease, diverticulitis, ischemic colitis, sexually transmitted diseases, or septic emboli from endocarditis. Management of postoperative fluid collections (POFCs) and pelvic abscesses can be technically challenging due to the need for navigation around multiple vital organs, including the bony pelvis, bowel loops, bladder, reproductive organs in females, prostrate in men, rectum, and other neurovascular structures. Undrained POFCs have a high morbidity and mortality. Historically these collections have necessitated surgery, ultrasound-guided transrectal or transvaginal intervention, or were drained percutaneously under computed tomography (CT) guidance. Recent advances in the field of interventional EUS have opened a new avenue for the management of POFCs and pelvic abscesses.
In cases of abdominopelvic abscess drainage, all patients should undergo dedicated CT or magnetic resonance imaging (MRI) of the abdomen and pelvis to define the anatomy and location of the fluid collection/abscess. If the POFC/pelvic abscess is multiloculated, measures less than 4 cm in size, has immature walls (without a definitive rim), is located at the level of the dentate line or greater than 2 cm from the EUS transducer, it should be managed by alternative techniques. Commonly it is recommended that patients be administered prophylactic antibiotics prior to the procedure. In case of POFC drainage, the overall procedural technique is similar to that of conventional EUS-guided drainage of peripancreatic fluid collections. In cases of pelvic abscess drainage, patients should undergo local preparation with an enema to optimize visualization and minimize contamination. Laboratory parameters must be checked to ensure that patients are not coagulopathic or thrombocytopenic. It is essential that the procedure take place in a unit equipped with fluoroscopy to guide stent and drain placements within the abscess cavity. Also, patients should either void prior to the procedure or have an indwelling Foley catheter to ensure that a distended bladder does not impair visualization of a small fluid collection or that it is not mistaken for an abscess.
The following procedural steps are undertaken in sequence:
First, POFC or the abscess must be located using a curved linear array echoendoscope. Once located, intervening vasculature must be excluded using color Doppler. Under EUS guidance, a 19-G fine-needle aspiration (FNA) needle is used to puncture the POFC or abscess cavity ( Fig. 26.3A–E ; Videos 26.4 and 26.5 ). The stylet is removed and the needle flushed with saline and aspirated to evacuate as much pus as possible. A sample of purulent material may be sent for gram staining and culture. A standard 0.035-inch guidewire or a stiff-type 0.025-in guidewire is then passed through the needle and coiled within the fluid collection. The needle is then exchanged over the guidewire for a 5-Fr endoscopic retrograde cholangiopancreatography (ERCP) cannula, needle-knife catheter, or cystotome to dilate the tract between gastrointestinal tract and the fluid collection. The tract is then further dilated using an 8-mm over-the-wire biliary balloon dilator.