Stent duodenum

The stent is advanced across the stricture until the tip is 3-4 cm beyond the ampulla. It is preferable to start deployment with the stent too far in, rather than not far enough, because it is easier to withdraw the stent into the correct position than it is to move it forward (Fig. 1.5). The peel-away sheath is retracted (not peeled) to above the stricture. The delivery-system outer sheath is retracted a few centimeters, which allows the distal uncovered end of the stent to partially expand. Accurate placement, with the tip just through the ampulla, is achieved by pulling back the whole assembly over the wire. As the partially expanded stent is withdrawn across the ampulla, the stent is mildly compressed, which corresponds to the location of the ampulla. The stent is positioned so that the distal 1-2 cm projects into the duodenum. After confirming that the upper end of the stent is within the ducts and well above the stricture, the stent is fuUy released by full retraction of... 

If a peroral route to the stomach outlet or duodenum is not feasible percutaneous gastrostomy using standard techniques (De Baere et al. 1997 Pinto et al. 2001) allows a more direct access. Using a stiff sheath successful catheterisation of the intestinal lumen beyond the obstruction is possible in virtually all cases and also stents mounted on shorter or relatively stiff introducing devices can then be implanted (Pinto 1997 Pinto et al. 2001 Keymling et al. 1993 Truong et al. 1992 Song et al. 1993). 

Fig. 3.7a, b. An 8-year-old patient with recurrent signs of obstruction 4 weeks after stent placement for pyloric stenosis, a A barium study shows obstruction of the outflow at the distal end of the stent due to abutting of the stent end to the wall of the descending duodenum, b There is good flow of barium after placement of a second stent coaxially... 

Fig. 30.3a,b. Adenocarcinoma with spread into duodenum and liver metastasis, a There is a large, low-density mass in the uncinate process (arrow), but the duodenum is not well seen. There is a metallic biliary stent in place, b Coronal MPR demonstrates tumor invasion into the ascending part of the duo-... 

Fig. 2.37a-c. Annular Pancreas. Double Contrast barium study (a) demonstrates semicircumferential narrowing of the duodenum due to an annular pancreas. Note the biliary stent. ERCP (b) shows the pancreatic ductal system encircling the duodenum. MRI (c) shows the pancreatic head, folded around the duodenal lumen... 

Fig. 11.9. a Injection of contrast shows a tight stricture at the gastric outlet (arrowheads). The radiopaque tip of the ERCP catheter (arrow) is seen at the distal end of the stricture in the second part of the duodenum (patient prone), b A wire has been passed across the stricture and a through-the-scope delivery system (arrowheads) is advanced over it (Enteral Wallst-ent, Boston Scientific, St. Albans, UK), c After stent release, marked waisting is seen at the level of the stricture. The stent has been placed too distally and the proximal end of the stricture is not covered, d A second Wallstent has been placed overlapping the first one and extending well into the gas-filled antrum (arrowheads). Note the position of the distal end of this (arrow) in the D1/D2 flexure, which may have caused impaction without the first stent... 

Historically, first attempts at duodenal stenting were performed with oesophageal stents inserted through a gastrostomy (Razzaq et al. 2001). On the whole the use of softer uncovered stents has become standard practice in the stomach and particularly in the duodenum. Covered stents have proved to have an unacceptably high migration rate and flexibility is of increased importance in order for the stent to conform to the flexures of the small bowel. 

Fig. 11.12a,b. Obstruction of the third part of the duodenum treated with a Hanaro stent (Diagmed, Thirsk, UK)... 

If the plastic stent is draining, the best course of action is to leave it alone and stent the duodenum. Depending on the level of duodenal obstruction, endoscopic access may be regained through the duodenal stent, if this can be placed with the distal end short of the papilla. Otherwise one has to accept that a transhepatic approach will be necessary for any future biliary intervention. 

If the duodenal stent is placed proximal to the plastic biliary stent, it may be possible to displace this into the duodenum percutaneously, should it occlude (Fotheringham et al. 2002). This is difficult, but gives better results than simply placing a metal stent alongside, as the plastic stent reduces expansion of the metal stent. 

The principle outlined earlier that the further the lesion from the mouth the more useful is an endoscope certainly applies in the duodenum. Whilst lesions in the second part of the duodenum can be stented without an endoscope, particularly if dedicated catheters are available (Song et al. 2004a), those in the third and fourth parts of the duodenum become extremely difficult. Without the endoscope to straighten out the tortuous route through stomach and the duodenal C , the catheter and even stiff wires tend to form loops in the distended stomach. 

Laasch HU, Martin DP, Maetani 1 (2005) Enteral stents in the gastric outlet and duodenum. Endoscopy 37 74-81 Lee S, Osugi H, Tokuhara T et al. (2005) Self-expandable metallic stent for unresectable malignant strictures in the esophagus and cardia. Jpn J Thorac Cardiovasc Surg 53 470-476... 

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