Oesophageal stents are widely used for palliating dysphagia from malignant obstruction. They are also used with increasing frequency in the treatment of oesophageal perforation, as well as benign strictures from a variety of causes. Improved oncological treatments have led to prolonged survival of patients treated with palliative intent; as a consequence, stents need to function and last longer in order to avoid repeat procedures. There is also increasing need for meticulous procedure planning, careful selection of the device most appropriate for the individual patient and planned follow-up. Furthermore, as more patients are cured, there will be more issues with resultant long-term side-effects, such as recalcitrant strictures due to radiotherapy or anastomotic scarring, which will have to be addressed. Stent design needs to keep up with the progress of cancer treatment, in order to offer patients the best possible long-term result. This review article attempts to illustrate the changing realities in oesophageal stenting, differences in current stent designs and behaviour, as well as the pressing need to refine and modify devices in order to meet the new challenges.

Background: Infra-colic radiologically inserted gastrostomy is not well documented, and the presence of an insertion window solely below the transverse colon is generally regarded as a contraindication to gastrostomy insertion. A perceived increased risk is due to the presence of vessels and lymphatics within the omental and peritoneal structures, such as the epiploic arteries, the arterial arcade of Barkow, and middle colic artery branches from the superior mesenteric artery. Colonic obstruction is also an additional theorised risk. We provide evidence that infra-colic insertion of a feeding tube through the greater omentum can be performed safely. Methods: A total of 1,156 gastrostomies were inserted over an 8-year period. A retrospective review of the 5 cases was conducted. Electronic patient records were reviewed including clinical consultations, procedure reports and images. Results: In all cases, barium was administered orally/per nasogastric tube the day before to delineate the colon. All patients underwent sedo-analgesia with insufflation of the stomach achieved by a temporising nasogastric/orogastric tube. Infra-colic gastropexy with three SafeTpexy T-fasteners was undertaken. Standard 12 Fr balloon retained tubes were inserted through the greater omentum with no post-procedural complications or tube malfunctions in four cases. A 16 Fr disc retained tube was inserted in a fifth case. Conclusion: Despite the perceived difficulties, we suggest that infra-colic gastrostomies can be performed with confidence, and with little deviation from standard insertion techniques. They can be inserted without an apparent increase in complications, although operators need to be aware of the anatomical differences and additional structures traversed when performing infra-colic gastrostomies.

Over the past 25 years, stents have developed into an established way of restoring luminal patency throughout the gastrointestinal tract. Materials used as well as the construction of these devices have become more and more sophisticated to comply better with the complex environment they are inserted in. The requirements vary greatly from organ to organ and stent behavior differs significantly between stent constructions. However, this is not necessarily appreciated by many operators. The choice of devices is now vast, and in many cases, decisions are made on availability and cost. An increasing challenge in malignant conditions is the improving survival of incurable patients, which now exceeds the traditional life expectancy of a stent by a factor of 2 to 3. Consequently, more patients experience failure of their stent and require repeat interventions. This has a poor impact on patients' quality of life and potentially on their survival. Re-intervention is often more difficult, carries the risk of additional complications, and presents an additional economic burden to the health systems.This article illustrates current stent designs, their different behaviors, and limitations.

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A B S T R A C TThe insertion of self-expanding stents into malignant strictures of the small and large bowel has become a routine procedure around the world. However, stent development has happened very much on a "trial & error" approach, based mostly on bright ideas of enthusiastic individuals or marketing decisions by the manufacturer. A large variety of stents are commercially available, covered to a variable degree by a membrane to reduce tissue ingrowth. However, in vitro characteristics and in vivo behavior vary significantly between stents and few operators are aware of the differences. While the ideal stent still remains to be defined, it is important that interventionists understand the variations, in order to make the best possible choice for the individual patient. This article illustrates current principles of stent construction.

Background: To investigate the expansion force of current colonic stents and to match these to industry standards. Methods: Samples of all colonic stents were requested from manufactures world-wide. Expansion forces were tested with an RX650 compression tool (MSI, Flagstaff, AZ, USA). Measurements were averaged over three cycles of compression and expansion, independently performed at 37°C by specialist engineers of MSI. In parallel, a survey was undertaken on standards, and tests used by manufacturers in their production process. As a labbased study, Institutional Review Board approval was not required. Results: A literature search did not identify any industry standards for testing expansion force or a suggested range for this primary stent function. Median expansion force of all stents was 24.4 N, (35.1 N for braided, 20.7 N for knitted stents) with a vast range from 5.6-130.8 N. Covering braided stents in liquid silicone increased their median force 5.5-fold, separate membranes attached to knitted stents only had a minor effect on expansion force. Five of eight manufacturers replied, describing three different test methods with three different units for expansion force. Conclusion: There are no standards on assessing expansion force, or what the ideal range should be. Consequently, the variation is remarkable, but values are not published, and even if they were, they could not be compared. Consequently, interventionists are unable to discriminate between different stents and to select the most suitable device for their patients, and no recommendation can be made on the 'best stent'. The industry needs an agreed test standard and an acceptable range of stent forces.

New "knitted" EGIS esophageal stent allows atraumatic inside-out removal by inversion Modern esophageal stents can be extracted by capture of a purse string. Under traction, braided stents lengthen and narrow. However, strictures are often friable, and extraction can cause hemorrhage or perforation. A new nitinol stent (EGIS; S&G Biotech, Seoul, Korea) consists of a "knitted" construction of interlinked wires, as used in enteral stents. Unlike in braided stents, no straightening forces exist within the skeleton, resulting in a resistance-free threedimensional conformation (• " Fig. 1) and reduced stent shortening on release compared with braided stents. Stent segments may move against each other, and the distal end can be inverted into the trunk by traction on the lower purse string. The stent peels away from the esophagus, reducing shearing forces on the surrounding tissues. We present two cases of stent removal in this novel fashion. Case 1: A 61-year-old man with a benign post-radiation stricture had suffered a perforation into the left main bronchus after balloon dilation during insertion of a biodegradable stent. The fistula was successfully occluded with an 18-mm, 9-cm EGIS esophageal stent. Bronchoscopy suggested healing, and stent removal was attempted under conscious sedation. Using rat-toothed forceps, the distal retrieval string was captured (• " Fig. 2) and the distal end of the stent inverted segment by segment, resulting in a sensation of falling dominoes. Removal was easy and atraumatic, but unfortunately the fistula remained.Case 2: A 69-year-old woman with a dilation-resistant post-radiation stricture had a biodegradable stent inserted. This did not expand adequately, resulting in episodes of food impaction. An 18-mm, 13-cm EGIS anti-reflux stent was placed coaxially, resulting in complete expansion of the biodegradable stent. The anti-reflux stent was removed by inversion 20 days later (• " Fig. 3,• " Video 1), leaving the fully expanded biodegradable stent in situ, with resulting grade-1 dysphagia. Interventionists must be aware of continued developments in stents, in order to offer patients the most appropriate option. Endoscopy_UCTN_Code_TTT_1AO_2AZCompeting interests: Derek Edwards currently serves as International Director for S&G Biotech. Hans-Ulrich Laasch has acted as technical consultant for S&G Biotech. Fig. 1 Open and valved e-PTFE (woven polytetrafluoroethylene)-covered EGIS esophageal stent with proximal and distal removal strings (arrows). Note the absence of straightening forces. Fig. 2 a Removal of an unvalved mid-esophageal stent: capture of the lower purse string (arrow) with endoscopic forceps. b The distal end of the stent is seen as a funnel (arrowheads) inverted into the stent trunk. The stent peels off the esophageal wall rather than pulling through the stricture. Note the dense radiopaque markers from the outer radiolucent biodegradable stent. Video 1Fluoroscopic view of endoscopic stent removal. After performing a J-manoeuvre in the stomach, the lower removal string res...

Advances in chemo-radiotherapy and cancer surgery are changing the landscape of esophageal stent insertion. Where previously patients received stents for end-stage esophageal carcinoma with a poor prognosis, long-term survival is beginning to become the norm. In addition more patients are undergoing radical surgery and consequently more patients are presenting with disease relapse in altered anatomy. Furthermore, patients with extraesophageal cancer can require stent insertion, but their underlying disease may run a different course from esophageal cancer. We illustrate the challenges for stent performance, material longevity and forward thinking of the operator presented by the change in disease spectrum and behavior.