stents used in gastroenterology

1. DR VARUN K

2.  History
 Introduction
 Types of Stents
 Indications for stenting
 Procedure
 Side effects
 Esophageal stents
 Gastroduodenal stents
 Colonic stents

3.  Invented in 1856 by the English dentist Charles Stent .
 Jan F. Esser, a Dutch plastic surgeon who in 1916 used the word stent to
describe a dental impression compound to craft a form for facial
reconstruction
 The first (self expanding) "stents" used in medical practice in 1986
by Ulrich Sigwart in Lausanne were initially called "Wallstents".
 Julio Palmaz et al. created a balloon expandable stent that is currently
used

4.  The evolution of enteral stents has gone through
stages over the last 125 years.
 Sir Charters Symonds was the first to successfully
place an esophageal prosthesis across a malignant
stricture.
 There were many modifications of rigid esophageal
stents in which various materials (wood, metal, plastic,
latex) and designs were used

5.  Celestin designed a new prosthesis and, following its commercial
availability in the 1970, the stent revolution accelerated.
 The rigid prosthesis (plastic and latex) was extensively used from the
1970s to the 1990s, but the complication rates and mortality associated
with insertion-related perforations remained significant.
 In the early 1990s, self-expandable metal stents (SEMS) were developed
for esophageal use a decade after their introduction into the vascular
and biliary tree

6.  Stents are devices used to maintain or restore the
lumen of hollow organs, vessels, and ducts.
 There are three types of expandable stents: metal,
plastic, and biodegradable

7.  There are three varieties of metal stents: uncovered,
partially covered, and fully covered.
 The advantage of covered stents is that they resist
tumor ingrowth, but they have a higher migration rate,
especially when fully covered but advantage of
potentially being removable.

8.  Partially covered stents are uncovered at their ends,
which allows the stent to embed in the tissue and
helps to prevent migration.
 Uncovered stents are less likely to migrate, but are
subject to tumor ingrowth and resultant obstruction.

9.  SEMSs consist of woven, knitted, or laser-cut metal
mesh cylinders that exert self-expansive forces until
they reach their maximum fixed diameter.
 SEMSs are composed of stainless steel, alloys such as
elgiloy and nitinol, or a combination of nitinol and
silicone.

10.  Elgiloy, an alloy composed primarily of cobalt, nickel,
and chromium, is corrosion resistant and capable of
generating high radial forces.
 Nitinol, an alloy of nickel and titanium, yields
increased flexibility that is helpful for stenting sharply
angulated regions at the cost of lesser radial force.

11.  To prevent tumor ingrowth, the interstices between
the metal mesh of esophageal SEMSs may be wholly or
partially covered by a plastic membrane or silicone.
 For tumors located near the GE junction (Esophageal
Z-stent with Dua Anti-reflux valve; Wilson-Cook
Medical, Winston-Salem, NC) uses an extended
polyurethane membrane 8 cm beyond the metal
portion of the stent to prevent gastroesophageal reflux

12.  An SEPS (Polyflex; Boston Scientific, Natick, Mass)
has been developed for esophageal strictures.
 This stent has a woven polyester skeleton and is
completely covered with a silicone membrane.

13.  The silicone prevents tissue in growth through the
mesh.
 Polyester braids on the external surface anchor the
stent to the mucosa to limit migration.

14.  Esophageal Degradable BD (Ella-CS, Czech Republic)
is made from woven surgical suture material,
polydioxanone.
 It is uncovered and does not have an anti-reflux valve.
 The stent fully degrades in approximately three
months

16.  PROXIMAL RELEASE
 DISTAL RELEASE
 COAXIAL RELEASE
 SUTURE RELEASE

19.  Dysphagia from esophageal malignancy.
 benign esophageal strictures (peptic, radiation
induced, anastomotic, and caustic).
 Postoperative leaks.
 iatrogenic perforations.

20.  external compression from extraesophageal tumors.
 tracheoesophageal fistulas.
 Achlasia cardia.
 Bleeding varices.

21.  Stents vary in length from 6 to 19.5 cm and in shaft
diameter from 10 to 23 mm.
 Wallflex (Boston Scientific, Inc, Natick, MA) – partially and fully
covered nitinol stents without an anti-reflux valve
 Esophageal Z stent (Cook Endoscopy, Winston-Salem, NC) – partially
covered stainless steel stent, available only with the Dua anti-reflux
variant

22.  Evolution (Cook Endoscopy) – partially covered and fully
covered nitinol stents without an anti-reflux valve
 Ultraflex stent (Boston Scientific, Inc) – partially covered and
uncovered nitinol stents without an anti-reflux valve
 Alimaxx-E stent (Merit Endotex) – fully covered nitinol stent
with and without an anti-reflux valve.
 Niti-S (Taewoong Medical Co, Korea) – fully covered nitinol
stent without an anti-reflux valve; this stent comes in two
versions, the covered Niti-S and the double-layered Niti-S that
has an additional layer of nitino

23.  ELLA-CS
 FerX-Ella Esophageal Stent -Stainless steel (fully
covered with polyethylene)
 SX-Ella Esophageal Stent- Nitinol (fully covered with
silicone)

29.  0—Able to consume a normal diet
 1—Dysphagia with certain solid foods
 2—Able to swallow semi-solid soft foods
 3—Able to swallow liquids only
 4—Unable to swallow saliva (complete dysphagia)

30.  Assessment of the length of the stricture and degree of
obstruction is the first step
 If the stricture is too tight to advance a standard
gastroscope, an ultrathin endoscope may be used.
 To guide accurate stent deployment, the proximal and
distal ends of the stricture need to be marked
appropriately

31.  During stent selection, it is important to choose a stent
length that is 4 cm longer than the stricture being
stented.
 This allows for 2 cm of stent on either end of the
stricture to decrease the risk of migration.

32.  Foreshortening is the property of the stent by which,
on fluoroscopy, the stent constrained in its catheter
will appear longer than the unconstrained deployed
stent length.
 stenting a stricture in the cervical esophagus ensure at
least a 2-cm distance between the proximal end of the
stent and the upper esophageal sphincter

35.  misplacement (0.3 percent),
 failed expansion (3.9 percent),
 failed deployment (0.8 percent), and
 migration (0.3 percent)
 gastroesophageal reflux disease (3.7 percent),
 recurrent dysphagia (8.2 percent),
 tracheoesophageal fistula (2.8 percent),

36.  bleeding (3.9 percent),
 perforation (0.8 percent), and
 death within 30 days that was not related to
immediate stent placement (7.4 percent)
 Esophageal self-expandable metallic stents--indications, practice, techniques, and
complications: results of a national survey.Ramirez FC, Dennert B, Zierer ST, Sanowski RA
Gastrointest Endosc. 1997;45(5):360

38.  Benign esophageal strictures are classified as simple or
complex.
 Simple strictures are straight and short (< 1 cm) and
can be easily passed with a normal diameter (8 to 10
mm) endoscope.
 Complex strictures are often longer (> 2 cm),
angulated, and sufficiently narrow that passing a
normal diameter endoscope is difficult.

39.  Complex strictures are due to radiation, photodynamic therapy, caustic
ingestions, and surgical anastomoses.
 Refractory strictures are defined as those that cannot be dilated to 14
mm over 5 sessions at 2-week intervals.
 Recurrent strictures are defined as those that do not maintain
satisfactory luminal diameter for 4 weeks after dilation to at least 14
mm.
Kochman M, McClave S, Boyce H. The refractory and recurrent esophageal stricture a
definition. . 2005;62(3):474-475

40.  SEPS should optimally be left in place for at least six
weeks to allow for remodeling of the scar tissue.
 A longer period may be required in patients with post-
radiation or anastomotic strictures, which have a
greater tendency to recur.

41.  Systematic review: the role of self-expanding plastic stents for benign
oesophageal strictures.Repici A, Hassan C, Sharma P, Conio M,
Siersema P Aliment Pharmacol Ther. 2010;31(12):1268.
Results:Data of 10 studies with 130 treated patients were included. SEPS
insertion was technically successful in 128 of 130 patients (98%)..

42.  A comparison of temporary self-expanding plastic and biodegradable
stents for refractory benign esophageal strictures. van Boeckel PG,
Vleggaar FP, Siersema P Clin Gastroenterol Hepatol. 2011;9(8):653
 Placement of SEPSs or biodegradable stents provides long-term relief
of dysphagia in 30% and 33%, respectively, of patients with RBES.
Biodegradable stents require fewer procedures than SEPSs, offering an
advantage. Although stent placement is a viable strategy in patients
with RBES, the ideal strategy still needs to be defined

43.  The use of expandable uncovered metal stents for
benign esophageal strictures is not recommended.

44.  Four studies examined the use of a FCSEMS without
flared flanges (Alimaxx-ES esophageal stent, Merit
Medical Systems Inc) in benign esophageal disease .
 Treatment success varied from 21 to 100 percent,
depending upon the indication for stent
placement (fistula/leak or perforation and strictures

45.  Three additional types of newly developed FCSEMSs
with the presence of flared flanges (ie, "dog bone"
design) have been used with success:
 Wallflex esophageal stent (Boston Scientific Inc, Natick, MA)
 Bonastent esophageal stent (EndoChoice Inc, Alpharetta, GA)
 Evolution esophageal stent (Cook Medical Inc, Winston-Salem, NC)

46.  A comparison of the temporary placement of 3 different self-
expanding stents for the treatment of
refractorybenign esophageal strictures: a prospective
multicentre study.
 Temporary placement of a biodegradable stent or of a FCSEMS in
patients with RBES may lead to long-term relief of dysphagia in 30 and
40% of patients, respectively. The use of SEPSs seems least preferable,
as they are associated with frequent stent migration, more
reinterventions and few cases of long-term improvement.

47.  In a retrospective study of 153 patients, Eickhoff and colleagues found
comparable rates of survival, recurrent dysphagia, and improvement in
dysphagia scores between SEMS and SEPS; however, SEMS had a much
lower complication rate than SEPS (9% vs 22%, respectively)
 Although SEPS have been shown to be effective, recent studies have
shown that they may not be preferred over SEMS.
 Eickhoff A, Knoll M, Jakobs R, et al. Self-expanding metal stents versus plastic prostheses in the
palliation of malignant dysphagia: long-term outcome of 153 consecutive patients. J Clin
Gastroenterol. 2005;39:877–885

48.  Self-expanding plastic stent to palliate symptomatic tissue
in/overgrowth after self-expanding metal stent placement
for esophageal cancer.
 Conio M, Blanchi S. Filiberti R, De Ceglie A.
 This case series supports the use of a SEPS to palliate dysphagia from
tissue in/overgrowth of a SEMS. Future clinical trials with larger
patient samples are warranted.

49.  Temporary self-expanding metallic stents for achalasia: A
prospective study with a long-term follow-up
 Ying-Sheng Cheng, Fang Ma, Yong-Dong Li, Ni-Wei Chen, Wei-Xiong
Chen, Jun-Gong Zhao, and Chun-Gen Wu
 A temporary SEMS with a diameter of 30 mm is
associated with a superior long-term clinical efficacy
in the treatment of achalasia compared with a SEMS
with a diameter of 20 mm or 25 mm.

50.  International Journal of Hepatolog Volume 2012 Role of Self-
Expandable Metal Stents in Acute Variceal Bleeding .Fuad
Maufa and Firas H. Al-Kawas
 SEMS placement using especially designed stent (SX-Ella Danis stent,
currently not available in USA) is a new promising alternative therapeutic
technique that can be used in patients with refractory esophageal variceal
bleeding. Patients who failed initial standard therapy, have
contraindications, or are unsuitable for those therapies are good candidates
at this time

51.  Esophageal malignancy: SEMS.
 Tumor ingrowth and dysphagia after SEMS: SEPS
 RBES: SEMS and Biodegradable stents.
 Tracheo-esophageal fistula: SEMS and if required
tracheal SEMS.
 Post op leaks: SEPS.

52.  Truong -1992 –First duodenal stent.
 Palliation of malignant gastric outlet obstruction in the
antrum, proximal small bowel, and gastroenteric
anastomoses .
 Benign gastric outlet obstruction.
 SEMS placement have demonstrated 95% technical success
and 85% to 95% clinical success with adequate
decompression of outlet obstruction and patients’ ability to
tolerate at least a mechanical soft diet.

53.  Wallflex Duodenal(Duloflex study)
 Wallstent Enteral (Boston Scientific),
 Evolution Duodenal (Cook Medical, Bloomington,IN)
 All uncovered SEMSs deployed through the
endoscope, have been approved for palliation of
malignant gastric outlet obstruction.

55.  A radiographic contrast study should first be obtained
to assess the length of the stricture and degree of
obstruction and to rule out additional sites of
obstruction
 Peritoneal carcinomatosis is a relative contraindication
to stent placement, although limited recent data
suggest that these patients have similar outcomes to
those without carcinomatosis

56.  If biliary obstruction is present or impending, it is
prudent to place a biliary stent before gastroduodenal
stenting to avoid difficult biliary access at a later date.
 Stricture dilation before stent placement is usually
unnecessary and carries a risk of perforation

57.  A throughthe- scope stent of appropriate size,
generally 4 cm longer than the size of the stricture, is
then advanced over the guidewire and deployed under
endoscopic an fluoroscopic guidance.
 At least a 2 cm length of stent should be flared at both
ends of the stricture to attain an appropriate “waist”;
otherwise, overlapping stents may be needed to fully
traverse the length of the stricture

59.  Mild adverse events include abdominal discomfort,
mild fever, and occasional vomiting without
obstruction.
 Major adverse events occurring within the first week
include bleeding, perforation, stent migration, severe
pain, fever, and jaundice
 Significant late adverse events include fistula
formation, stent obstruction, late perforation or
bleeding, biliary obstruction, and stent migration

60.  Surgical gastrojejunostomy or endoscopic stent placement for
the palliation of malignant gastric outlet obstruction (SUSTENT study):
a multicenter randomized trial.Jeurnink SM, Steyerberg EW, vanHooft
JE, van Eijck CH, Schwartz MP, Vleggaar FP, Kuipers EJ, Siersema
PD Dutch SUSTENT Study Group
 CONCLUSIONS: Despite slow initial symptom improvement, GJJ was
associated with better long-term results and is therefore the treatment of
choice in patients with a life expectancy of 2 months or longer.
Because stent placement was associated with better short-term outcomes, this
treatment is preferable for patients expected to live less than 2 months.

61.  Safety and efficacy of a new non-foreshortening nitinol
stent in malignant gastric outlet obstruction (DUONITI
study): a prospective, multicenter studyvan Hooft JE, van
Montfoort ML, Jeurnink SM, Bruno MJ, Dijkgraaf MG, Siersema
PD, Fockens P.Endoscopy. 2011 Aug;43(8):671-5
 Placement of a new non-foreshortening nitinol enteral stent is safe and
without major complications. This stent design produces significant
relief of obstructive symptoms and improves quality of life in patients
with incurable malignant GOO

62.  Endoscopic stent management of leaks and
anastomotic strictures after foregut surgery.
Yimcharoen P, Heneghan HM, Tariq N, Brethauer SA, Kroh
M, Chand B.Surg Obes Relat Dis. 2011 Sep-Oct;7(5):628-36
 Endoscopic stent management of anastomotic
complications after foregut surgery is effective in resolving
symptoms, expediting enteral nutrition, and particularly
successful for treating anastomotic leaks.

63.  Application of stent placement or nasojejunal feeding tube
placement in patients with malignant gastric outlet obstruction: a
retrospective series of 38 cases. Lin CL, Perng CL, Chao Y, Li CP, Hou MC,
Tseng HS, Lin HC, Lee KC.J Chin Med Assoc. 2012 Dec;75(12):624-9
 NJ tube placement and duodenal stent placement are both effective and
safe treatments for patients with MGOO. Both groups had similar
complication rates and survival rates. While NJ tube placement is
associated with lower costs, stent placement has a longer duration of
patency, superior oral intake, and a lower reintervention rate. We suggest
that stent placement should be considered first in patients who are able to
afford the related costs

64.  Antral localization worsens the efficacy of enteral stents in
malignant digestive tumorsDolz C, Vilella À, González Carro P,
González Huix F, Espinós JC, Santolaria S, Pérez Roldán F, Figa M,
Loras C, Andreu H.Gastroenterol Hepatol. 2011 Feb;34(2):63-8
 The palliative treatment of malignant gastric outlet obstruction with a
uncovered metal stent produces a significant improvement of oral food
intake and maintains the overall quality of life index. The antral
localization is associated with a lower efficacy of the procedure

65.  Colorectal stenting has become an important tool in
the palliation of advanced disease
 Management of acute colon obstruction as a possible
bridge to Surgery
 Benign colon strictures
 Clinical success rates, defined as relief of obstructive
symptoms, are reported in 85% to 90% of patients.

68.  Colon SEMSs may be covered or uncovered,
throughthe- scope or not through-the-scope
 Only uncovered stents are currently approved in the
United States
 Smaller-diameter stents are generally used in the right
side of the colon and larger-diameter stents in the left
side of the colon to prevent solid stool impaction.

69.  Ideally, a radiologic imaging study such as a barium
enema or CT scan with rectal contrast should be
obtained before stent placement to assess the degree
of obstruction and the length and location of the
stricture
 Prophylactic antibiotics should be considered in
patients with complete obstruction because air
insufflation may lead to microperforation

70.  When the colonoscope is advanced, air insufflation
should be minimized to avoid the risk of proximal
bowel distension and perforation.
 Ideally, a 2-cm segment of stent should be spared
beyond both the proximal and distal edges of the
stricture to allow the formation of a waist in the
middle and a flare at both ends.

71.  Rectal stents should be deployed at least 2 cm
proximal to the anal verge to avoid pain and
incontinence
 Stents that are not through-the-scope are deployed
under fluoroscopic guidance by using a stiff guidewire,
and endoscopic views may be obtained by advancing a
regular gastroscope alongside the stent delivery system

73.  Successful stent deployment is generally associated
with immediate passage of stool and flatus.
 Failure to achieve decompression could be a result of
incomplete stenting of the entire length of the
stricture, additional sites of intestinal obstruction,
early stent migration, incomplete expansion of the
stent, or fecal impaction.

74.  Perforation,
 bleeding,
 Stent migration,
 abdominal pain,
 recurrent obstruction due to stent malposition, and
tissue or tumor ingrowth overgrowth.
 Rectal SEMS placement may cause tenesmus and
incontinence.

75.  Comparison of uncovered stent with covered stent for treatment
of malignant colorectal obstruction.
 Lee KM, Shin SJ, Hwang JC, Cheong JY, Yoo BM, Lee KJ, Hahm KB, Kim
JH, Cho SW Gastrointest Endosc. 2007 Nov;66(5):931-6
 Insertion of either an uncovered or covered stent is similarly an
effective treatment modality of malignant colorectal obstruction for
preoperative purposes. However, there are no advantages of covered
stents over uncovered stents during the follow-up period in the
palliative purpose

76.  colonic stenting for malignant obstruction is associated with less
morbidity and cost but no difference in overall survival.
 Targownik LE, Spiegel BM, Sack J, et al. Colonic stent vs emergency surgery for
management of acute left-sided malignant colonic obstruction: a decision analysis.
Gastrointest Endosc 2004;60:865-74.
 Cheung HYS, Chung CC, Tsang WWC, et al. Endolaparoscopic approach vs conventional
open surgery in the treatment of obstructing left-sided colon cancer. Arch Surg
2009;144:1127-32.

77.  Colorectal Dis. 2014 Apr;16(4):239-45. doi: 10.1111/codi.12389.
 Systematic review of self-expanding stents in the management
of benign colorectal obstruction.
 Currie A, Christmas C, Aldean H, Mobasheri M, Bloom IT
Complication rates in stenting for benign colorectal obstruction are
higher than for malignant obstruction. On the basis of limited
published evidence, stenting cannot be recommended
for benign colorectal obstruction

78.  A retrospective analysis of early and late outcome of
biodegradable stent placement in the management of refractory
anastomotic colorectal strictures.
 Repici A, Pagano N, Rando G, Carlino A, Vitetta E, Ferrara E, Strangio
G, Zullo A, Hassan C Surg Endosc. 2013 Jul;27(7):2487-91
 This retrospective analysis of a limited number of patients
demonstrated that nondedicated esophageal BD stents are
associated with high risk of migration and clinical success in less
than 50 % of patients. Dedicated stents with large diameter and
antimigration findings could potentially improve the outcome of
patients with refractory benign colorectal strictures

79.  Malignant colorectal obstruction: SEMS
 Covered and Uncovered stents equal efficacy.
 Benign strictures: No role of stents

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