Esophageal, Gastroduodenal, and Colorectal Stenting


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Esophageal, Gastroduodenal, and Colorectal Stenting


Peter D. Siersema


Radbboud University Medical Center, Nijmegen, The Netherlands


Procedure(s) to be considered


Procedures that are required for stent placement in the gastrointestinal (GI) tract include endoscopy with a small (4–6 mm) or normal (8–10 mm) caliber gastroscope for strictures in the esophagus, a large (11.5–14 mm) caliber gastroscope or therapeutic duodenoscope (11–12.5 mm) for strictures in the distal stomach/duodenum, and a sigmoidoscope or colonoscope (12–14 mm) for strictures in the colorectum (Figure 25.1).


These endoscopic procedures are used for stent placement in the esophagus, distal stomach/duodenum, and colorectum. These strictures are often malignant; however, benign strictures can also be stented, particularly in the esophagus. In addition, stents are placed for malignant esophagorespiratory fistulas and for benign esophageal leaks or ruptures.


Prerequisite level of expertise and skill for learning this


Basic prerequisites for learning to place stents include skill in upper endoscopy and colonoscopy, interpretation of fluoroscopic images, and experience in general stricture dilation techniques. Prior ERCP training is also very helpful.


There is a large variety in the degree of difficulty for stent placement. In general, esophageal stents are easiest to place, although the degree of difficulty may also vary. For example, stent placement of a midesophageal obstruction is usually straightforward, but proximal esophageal lesions are often more challenging to stent.


Gastroduodenal and colorectal stents are more difficult to place, which is due to the severity of these obstructions and the local anatomical situation. Endoscopists, who also perform more complex procedures, such as ERCP, should however be able to traverse complex gastroduodenal and colorectal strictures, to interpret difficult fluoroscopic images, and to adequately place stents for malignant obstructions. In general, colorectal stent placement in the setting of an acute complete obstruction is difficult, since the patient is ill, bowel preparation inadequate, the anatomy angulated, and the lumen frequently not seen en face.


Another issue is the variety of stents and stent delivery systems that are currently available. It is difficult to master all of the specific characteristics of stents and their deployment systems. All currently available stents have their own degree of shortening in the GI tract.


Special considerations


The necessary skills for stent placement in the GI tract are best obtained in high‐volume tertiary referral centers. Patients requiring stent placement are often seen in centers with a high number of referrals for therapeutic endoscopy and/or a large GI oncology practice. The trainee must be supervised by a senior endoscopist (trainer) with expertise in stent placement for different types of strictures throughout the GI tract. The training is supported by instruction in dilation techniques for strictures. It is prerequisite that the trainee is familiar with indications for stent placement, knows contraindications for procedures, and is able to anticipate and to act upon complications that occur due to stenting [1].


Specific technical and cognitive skill sets


Stent placement requires sufficient cognitive skills with regard to the:



  • indications for stenting malignant and benign strictures throughout the GI tract, benign esophageal ruptures and leaks, and esophagorespiratory fistulas;
  • interpretation of noninvasive imaging results, such as computed tomography (CT) and contrast swallow;
  • evaluation of clinical signs and symptoms following stent placement;
  • available (endoscopic and nonendoscopic) management options for complications and recurrent obstruction;
    Photo depicts endoscopes for stent placement in the gastrointestinal tract, from left to right: small caliber gastroscope, therapeutic duodenoscope, normal caliber gastroscope, large caliber gastroscope, sigmoidoscope, and colonoscope.

    Figure 25.1 Endoscopes for stent placement in the gastrointestinal tract, from left to right: small caliber gastroscope, therapeutic duodenoscope, normal caliber gastroscope, large caliber gastroscope, sigmoidoscope, and colonoscope.


  • optimal timing for stent removal in benign indications; and
  • placement of an additional (second) stent in case of stent dysfunction.

Necessary technical skills include therapeutic upper and lower endoscopy, guide wire placement, and biliary stent placement. As stent placement is sometimes indicated in extremely tight strictures, the trainee should also be able to dilate these strictures using balloon or Savary‐Gilliard dilation. Training in dilation techniques is covered in Chapter 17 of this volume. Moreover, as stent placement for benign indications is increasingly being performed, the trainee should have the skills to remove various types of stents.


The ability to manage procedure‐related (e.g., perforation, hemorrhage) and long‐term (e.g., fistula formation) complications and recurrent obstruction due to stent migration, tumoral or nontumoral tissue overgrowth, or food obstruction is essential.


It is important to note that the location of the stricture and its relation to surrounding organs are important to consider prior to stent placement. This is particularly true for obstructions in the proximal and midesophagus, benign esophageal ruptures and leaks, and gastric outlet obstruction.


Finally, it is important for trainees to develop skill in coordinating care with other providers such as oncologists, radiologists, general surgeons, and interventional bronchoscopists, in the event of proximal esophageal tumors that threaten upper airway compression.


Equipment



  1. Esophagus

    1. Small (4–6 mm) or normal (8–10) caliber gastroscope
    2. Materials for marking the upper and lower tumor margin:•

      • Injection needle with lipid‐soluble contrast agent such as lipiodol
      • External marker with tape to fixate

    3. 0.018–0.038” stiff guide wire (preferably stiff)
    4. Bougie or balloon dilation (max. 10–12 mm)
    5. Partially or fully covered metal or nonmetal stent placed over the wire (OTW)

  2. Distal stomach/duodenum

    1. Large (11.5–14 mm) caliber gastroscope or therapeutic duodenoscope (11–12.5 mm)
    2. ERCP catheter
    3. Water‐soluble contrast agent
    4. 0.018–0.038” guide wire (flexible)
    5. Balloon dilation (max. 10–12 mm)
    6. Uncovered or covered metal stent placed TTS

  3. Colon/rectum

    1. Sigmoidoscope or colonoscope (12–14 mm)
    2. Materials for marking the upper and lower tumor margin:•

      • Injection needle with lipid‐soluble contrast agent

    3. ERCP catheter
    4. Water‐soluble contrast agent
    5. 0.018–0.038” guide wire (flexible)
    6. Balloon dilation (max. 10–12 mm)
    7. Uncovered or covered metal stent placed OTW [distal colon/rectum (rarely used these days)] or TTS

  4. Salvage accessories

    1. Hemostasis accessories—injection needle, epinephrine, endoclips, bipolar
    2. Rat‐toothed forceps—therapeutic size
    3. Polypectomy snare
    4. Overtube

Key steps of proper technique


Esophagus


Stent placement for palliation of dysphagia or closure of esophagorespiratory fistulas is an alternative treatment option for patients who are otherwise not candidates for surgical resection. In addition, stents are increasingly used for (prolonged) dilation of benign esophageal strictures and for sealing benign esophageal ruptures or leaks [2].


Pre‐esophageal stenting evaluation


Prior to esophageal stent placement, the endoscopist should evaluate the following items:



  1. Patient condition

    In malignant esophageal strictures, it is important to decide whether the patient is “fit enough” to benefit from stent placement. In patients with a WHO performance score of 4 (100% bedridden), the indication should be carefully evaluated.


  2. Tumor location

    Esophageal tumors can be located in the proximal, mid‐, or distal esophagus. For tumors in the proximal and midesophagus, there is a risk of coexisting tumor ingrowth into the trachea or bronchus or tumor compressing the airways. Placement of a tracheal stent should be considered prior to esophageal stent placement. Stents across the gastroesophageal junction (GEJ) are at an increased risk of migration. There is also a risk of gastroesophageal reflux. Moreover, the distal stent end may damage the stomach wall at the level of the lesser curvature when the stent is placed too distally.


  3. Stent choice

    Partially or fully covered stents are now the predominantly used stent types in the esophagus (Table 25.1) (Figure 25.2). It has been shown that the functional result of uncovered esophageal stents is negatively affected by the high risk of tissue ingrowth through the uncovered stent mesh [3].


    Recurrent dysphagia due to stent migration, tissue in‐ or overgrowth, or food impaction is currently the most important cause of a poorly functioning stent. Stent designs have usually one or more items that may prevent recurrent dysphagia (Table 25.2). The optimal stent choice in a particular clinical situation is an important issue. In malignant esophageal strictures, partially covered stents are a valuable option.


    In benign strictures, fully covered metal or plastic stents are preferable as the risk of nontumoral (hyperplastic) tissue ingrowth is reduced with these designs, making stent removal easier.


    In benign esophageal ruptures or leaks without a stricture, large caliber covered stent devices are the stent type of choice. If a normal caliber stent is used, migration is a risk. Although fully covered stents can easier be removed than partially covered stents, many experts prefer a partially covered stent in this situation, as the uncovered parts of the stent allow complete sealing and anchoring of the stent.

    Photo depicts currently available covered metal esophageal stents.

    Figure 25.2 Currently available covered metal esophageal stents, from left to right: Ultraflex (Boston Scientific, Natick, MA, USA), Polyflex (Boston Scientific), WallFlex Esophageal (Boston Scientific), Evolution Esophageal (Cook, Limerick, Ireland), SX‐Ella (Ella, Hradec Kralove, Czech Republic), Niti‐S (Taewoong, Seoul, South Korea), and Alimaxx‐E (Merit, South Jordan, UT, USA). As can be seen, some of these stents are fully covered, whereas others are only partially covered.


    This is however a nonregistered indication of partially covered stents.


    Table 25.1 Characteristics of some the currently used partially or fully covered self‐expanding esophageal stents.




























































































    Stent type Covering Length (cm) Diameter (mm) Release system Radial force Degree of shortening Flexibility Material Stent manufacturer
    Ultraflex Partial 10, 12, 15 18, 22 Proximal/distal Low 30–40% High Nitinol/polyurethane Boston Scientific, Natick, MA, USA
    Polyflex Full 9, 12, 15 16, 18, 21 Distal High 0% Low Polyester/silicone Boston Scientific, Natick, MA, USA
    WallFlex Partial/Full 10, 12, 15 18, 23 Distal High to strong 30–40% Moderate Nitinol/silicone Boston Scientific, Natick, MA, USA
    Evolution Partial/Full 8, 10, 12.5, 15 20 Distal Moderate 10–20% Moderate Nitinol/silicone Cook Medical, Limerick, Ireland
    SX‐Ella Full 8.5, 11, 13.5 20 Distal High 10–20% Low Nitinol/polyethylene Ella, Hradec, Kralove, Czech Republic
    Niti‐S Full 6, 8, 10 12, 15 18 Proximal/distal Moderate 10% Moderate Nitinol/polyurethane Taewoong, Seoul, South Korea
    Alimaxx‐E Full 7, 10, 12 18, 22 Distal Low 0% Moderate Nitinol/polyurethane Merit, South Jordan UT, USA

    Table 25.2 Characteristics of currently used covered stents to minimize recurrent dysphagia.







    • Tissue in‐ and overgrowth

      • Cover over entire stent length
      • Nonmetal/nonnitinol material
      • Expansion force that is intermediate between too high and too low


    • Food obstruction

      • Larger diameter
      • Cover on luminal inside


    • Migration

      • Resistance on outside of stent
      • Larger diameter
      • Shouldering of stent
      • Partial cover of stent (leaving proximal and distal stent parts uncovered allowing them to embed)

    It is generally believed that stents placed for a tumor causing extrinsic esophageal compression are at an increased risk of migration. Unfortunately, this is not based on comparative studies. Nevertheless, many experts place partially covered stents for extrinsic compression to reduce migration risk.


    Stents are increasingly being used for strictures in the proximal esophagus, close to the upper esophageal sphincter (UES). Placement at this site requires careful positioning, as the upper stent end should not extend above the UES to prevent the risk of foreign body sensation. Other complications include stent‐induced pain and tracheal compression. If the latter is the case, initial tracheal stent placement is advised. It is recommended that the endoscopist should be skilled and experienced in placing stents in the proximal esophagus. Finally, it is recommended to use only flexible stent designs, for example, the Ultraflex stent (Boston Scientific, Natick, USA) to minimize the risk of complications. As all currently available stents have specific advantages but also drawbacks, we suggest to develop experience with a small selection of stent types, for example, one partially covered metal stent and one fully covered metal or nonmetal (plastic) stent.


  4. Coagulation parameters

    Hemorrhage is not a very common procedure‐related complication in esophageal stent placement; however, if occurring, it may have a dramatic outcome. Although routine evaluation of coagulation parameters is not indicated, it is recommended to control prothrombin time (PT) and activated partial thromboplastin time (APTT) when risk factors for abnormal results present, such as warfarin or heparin use or liver dysfunction.


Esophageal stent placement


c25i001 In this section, the antegrade technique (Video 25.1) and the combined antegrade and retrograde (CAR) technique for esophageal stent placement are separately discussed.


Antegrade technique

For antegrade stent placement, the following steps need to be taken:



  1. Stent placement is usually done with the patient under moderate sedation.
  2. As a first step, the upper and lower margins of the tumor need to be identified (Figure 25.3a). If tumor obstruction does not allow passage of a standard gastroscope, the tumor can be dilated to 10–12 mm to measure stricture length and place a guide wire. However, dilation carries an increased risk of perforation. Therefore, it is preferable to use a small caliber gastroscope.
  3. When stents are placed under fluoroscopic guidance, the proximal and distal margins of the stricture are demarcated by placing skin markers, clips, or intramucosal injection of a radiopaque contrast agent (Figure 25.3b). It should be reminded that injecting lipid‐soluble contrast agent will result in a persistent mark in the mucosa.
  4. The next step is to place a stiff guide wire, for example, a 0.038‐inch Savary guide wire or 0.035‐inch Amplatz guide wire, as distally as possible, preferably the duodenum. A stiff guide wire is preferred over a more flexible type as this reduces the risk of kinking. This is important as esophageal stents are usually introduced over a guide wire. A duodenal position of the guide wire is preferred, because some stent introduction systems have a tip that far extends the distal end of the stent.
  5. The stent is then advanced over the guide wire. Most stents shorten during expansion (Table 25.1), which must be taken into account when positioning the introduction system. In order to prevent stent migration upon release from the introduction system, the system should not be advanced too distally. A stent that is no longer than 2–4 cm > the stricture length should be used to allow for a 1–2 cm extension above and below the proximal and distal tumor margins. For stents placed across the GEJ, stent length is guided by the rule that the distal stent end should not overlap the distal tumor margin by more than 1–2 cm to prevent laceration of the posterior stomach wall at the distal stent end and avoid kinking of the stent.
  6. Stents can be placed under fluoroscopic and/or endoscopic control or using the markers on the stent introduction system as is the case with Ultraflex stents (Boston Scientific, Natick, USA) and SX‐Ella stents (Ella‐CS, Hradec Kralove, Czech Republic). Recently, preliminary experience has been reported with esophageal stents placed through the scope. It was reported however that in some situations still fluoroscopic control was required for correct positioning, because therapeutic gastroscopes need to be used that cannot pass a stricture. There is no objection to confirm endoscopically that the upper end of the stent is optimally placed. However, one should be careful to avoid stent dislodgement caused by friction between the still insufficiently deployed stent and the endoscope (Figure 25.3

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Jul 31, 2022 | Posted by in GASTOINESTINAL SURGERY | Comments Off on Esophageal, Gastroduodenal, and Colorectal Stenting

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