Guidewires in GI endoscopy

Background

Guidewires (GWs) are ubiquitous in the endoscopy suite, because they represent a basic but invaluable tool for diagnostic and therapeutic endoscopy. GWs can be used in the GI lumen, within the pancreatic and biliary ducts to facilitate advancement of accessories and to maintain access in extraluminal collections and adjacent structures. In those procedures where GWs are used, GW design, quality, and performance characteristics are considered a critical factor in the efficacy, safety, and efficiency of planned therapeutic endoscopic interventions.

Technology Under Review

A myriad of different GW types exists, some for general applications and others with specific, more specialized functionality. Advancement of devices is best achieved over stiff, large-caliber GWs with countertraction to minimize lateral deviation and transmit forward axial forces. Contrarily, entry into narrow and irregular spaces may necessitate the use of soft, small-caliber, and/or angled and more flexible GWs. GWs vary in composition materials, diameter, tip shape, and tip and shaft stiffness, with many designed for specific indications, as detailed in Table 1. This document provides an update to the American Society for Gastrointestinal Endoscopy document published in 2007.¹

Table 1.

Guidewire specifications

Wire (manufacturer)	Diameter (in)	Length (cm)	Shaft style	Tip	Tip length (cm)	Hydrophilic length (if applicable) (cm)	Core material	Sheath material	Primary use	Cost (U.S.$)
Amplatz Super Stiff (BSC)	.038	260	Super stiff	Straight	N/A	N/A	Stainless steel	PTFE	Dilation	326
Dreamwire (BSC)	.035	260, 450	Standard Stiff	Straight, angled (hydrophilic)	10	10	Nitinol/nickel titanium	PTFE	Pancreaticobiliary	367.50
Hydra Jagwire (BSC)	.035	260, 450	Standard Stiff	Straight, angled (hydrophilic both tips)	5 and 10	5 and 10	Nitinol/nickel titanium	PTFE	Pancreaticobiliary	367.50
Jagwire (BSC)	.025, .035	260, 450	Standard Stiff	Straight, angled (hydrophilic)	5	5	Nitinol/nickel titanium	PTFE	Pancreaticobiliary	262.50
Jagwire Revolution (BSC)	.025	260, 450, 500	Standard	Straight, angled (hydrophilic)	5	5	Nitinol/nickel titanium	PTFE	Pancreaticobiliary	367.50
NaviPro (BSC)	.018, .025, .035	260	Standard Stiff	Straight, angled (entire wire hydrophilic)	3	260	Nitinol/nickel titanium	PTFE	Pancreaticobiliary	309
NovaGold (BSC)	.018	260, 480	Standard	Straight (hydrophilic)	6	30	Triton alloy	PTFE	Pancreaticobiliary	367.50
Wallstent Super Stiff (BSC)	.035	500	Standard	Tapered	N/A	N/A	Stainless steel	N/A	Dilation and stent placement	211
RevoWave (Olympus)	.025, .035	260, 450, 550	Standard Stiff Super stiff	Straight, angled	5 7	5 7	Titanium nickel alloy	PTFE	Pancreaticobiliary, altered anatomy ERCP, and luminal dilation/stent placement	204.50
VisiGlide (Olympus)	.025, .035	270, 450	Standard	Straight, angled	7	7	Nitinol	PTFE	Pancreaticobiliary	320.20
VisiGlide 2 (Olympus)	.025, .035	270, 450	Standard	Straight, angled	7	7	Nitinol	PTFE	Pancreaticobiliary	320.20
Glidewire (Olympus)	.018 .020, .025, .035, .038	150, 260, 450	Standard Stiff	Straight, angled	3 5 8	150 260 450	Nitinol	PTFE	Pancreaticobiliary	429.50
Acrobat 2 (Cook)	.025, .035	260, 450	Standard	Straight, angled	4	5.8	Nitinol	PTFE, platinum spring coil	Pancreaticobiliary	245
Tracer Metro (Cook)	.021, .025, .035	260, 480, 600	Standard	Straight, angled (.035-inch)	5	5	Nitinol	PTFE	Pancreaticobiliary and altered anatomy ERCP	207
Roadrunner (Cook)	.018	260, 480	Standard	Straight, angled	3	3	Nitinol	PTFE	Pancreaticobiliary	204
Delta Wire (Cook)	.025, .035	260		Straight, angled	N/A	260	Nitinol	Polyurethane	Pancreaticobiliary	165
Standard (Cook)	.035	480	Standard	Straight	N/A	N/A	Nitinol	PTFE	Pancreaticobiliary	104
Savary-Gilliard (Cook)	.032	200, 250, 360	Super stiff	Straight (coiled)	N/A	N/A	Stainless steel	N/A	Dilation	427
Marked Spring Tip Guidewire (Micro-Tech)	.07	210	Stiff	Straight (coiled)	N/A	N/A	Stainless steel	N/A	Dilation	129
Flex-Ez (Hobbs)	.035	260, 400, 480	Standard	Straight	7	7	Stainless steel	PTFE	Pancreaticobiliary and luminal dilation/stent placement	45
XWire (ConMed)	.025, .035	260, 450	Standard stiff	Straight, angled	5	5	Nitinol	PTFE	Pancreaticobiliary	182
FXWire (ConMed)	.035	260, 450	Standard	Straight, angled	5	5	Nitinol	PTFE	Pancreaticobiliary	196

BSC, Boston Scientific Corporation; PTFE, polytetrafluoroethylene; N/A, not available.

GW principles

The use of GWs for the advancement of endoscopic devices operates on the interplay between friction and flexibility. Slippery and flexible GW tips and shafts can gain selective ductal access, but their lack of friction can hinder the use of effective countertraction to advance devices. Similarly, stiff and taut GWs can create the friction needed when countertraction is applied to facilitate device advancement but are more challenging to maneuver into specific ducts. Therefore, endoscopists need to consider the various design elements of GWs, including thickness, tip shape, flexibility, stiffness, and coating, before choosing a GW for a specific indication.

GW design and composition

GWs for use in the GI tract are manufactured in 1 of 3 designs: monofilament, coiled, or coated:

• 1.Monofilament GWs are typically constructed with stainless steel, which provides intraprocedural rigidity and stability. Monofilament GWs are primarily used to facilitate the passage of dilation devices such as esophageal polyvinyl dilators.
• 2.Coiled GWs contain an inner monofilament core (mandrel), which imparts the GW stiffness, and an outer spiral coil, which promotes GW flexibility and durability. The inner and outer components are made of stainless steel. Coiled GWs are often painted with polytetrafluoroethylene to reduce friction.
• 3.Coated (also known as sheathed) GWs contain a monofilament core and an outer sheath made of either polytetrafluoroethylene, polyurethane, or another smooth polymer (Fig. 1). The monofilament core or shaft is typically composed of nitinol or alternative memory metal alloy that retains its shape, whereas the outer sheath or “jacket” is designed for enhanced fluoroscopic visualization and hydrophilicity for improved ease of passage. Hydrophilicity is a common feature of GWs used in the pancreatobiliary tract whereby the coating (either at the tip of the GW or the entire length of the GW) is designed to facilitate smooth cannulation and passage into the various ducts and associated branches. Typically activated by flushing, the plastic sheathing covered with hydrophilic material becomes very slippery. Outside of the body, however, hydrophilic wires carry the tendency to dry out and become sticky, thus requiring constant dampening with saline solution or water.

Figure 1.

Examples of coated guidewires with cores (yellow) composed of a monofilament (typically nitinol) and outer coatings (blue) typically made with polytetrafluoroethylene. (Used with permission from Sakai Y, Tsuyuguchi T, Hirata N, et al. Clinical utility of 0.025-inch guidewire VisiGlide2 in the ERCP-related procedures. World J Gastrointest Endosc 2017;9:77-84.)

GW length

GWs range in length from 260 to 270 cm for “short” GWs and from 450 to 500 cm for “long” GWs. Of special mention are GWs designed for use with enteroscopes, which range in length from 550 to 600 cm and operate on the same principles as a long GW. In general, GW diameters range from .018 inches to up to .07 inches (.46-1.78 mm) and have cores dipped in tungsten or platinum to enhance fluoroscopic visualization.

GW tip

GW tips vary in design, with either straight, angled, J-shaped, or tapered configurations available (Fig. 2). Radiopaque markers may be present on the GW tip to aid in fluoroscopic movement and measurements. The purpose of angled GWs is to offer maximal torqueability and tip flexibility for selective cannulation of desired ductal branches, to navigate through tight ductal strictures, or for advancement in a challenging GI lumen. The flexible, angled tip also allows the endoscopist to form a loop shape with the GW, within the duct, thus creating a stable, relatively atraumatic proximal anchor point for accessory exchange and advancement. Furthermore, a loop shape may decrease adverse events such as ductal perforation and post-ERCP pancreatitis (PEP) by preventing the sharp tip of a GW from puncturing through the duct or side branch; however, this concept has only been studied in ex vivo models, and clinical data are lacking.² Angled GWs include a torque device (ie, a vice) that can be affixed to the GW externally to facilitate GW rotation. The length of the GW tip varies between different models, typically ranging from 3 to 10 cm in length. Because the tips are typically hydrophilic, longer tips are believed to offer greater wire lubrication to facilitate selective cannulation. Several randomized trials have demonstrated higher selective cannulation rates with the use of angled GWs compared with straight GWs, but further trials are needed to compare the different types of angled GWs.^3,4 Of note, even with the use of torqueing devices, straight GWs are inherently challenging to manipulate for selective cannulation.

Figure 2.

Different types of guidewire tips. A, Straight and angled tips. (Courtesy of Boston Scientific.) B, J-shaped tip. (Used with permission from Omuta S, Maetani I, Shigoka H, et al. Newly designed J-shaped tip guidewire: a preliminary feasibility study in wire-guided cannulation. World J Gastroenterol 2013;19:4531-4536.)

GW use

Within the field of endoscopy, GWs are advanced within the GI tract under direct endoscopic visualization, fluoroscopic guidance, or both. Although GWs can be advanced through an assortment of accessories such as catheters, sphincterotomes, and dilation balloons, GWs can also be advanced directly out of the working channel of the endoscope without the use of an accessory. Once the GW is positioned in the desired location, it can then be used to guide catheters, support device insertion, exchange devices, and maneuver through strictures. A common practice is to continuously moisten hydrophilic GWs to prevent drying, which leads to excessive friction and resistance.

Indications and Efficacy

ERCP

GWs remain a central accessory in performing ERCP. GWs allow selective access into the bile duct or pancreatic duct and are crucial for the advancement of devices such as sphincterotomes, extraction balloons, dilation devices, and stents. All GWs used in ERCP are intended to be single use to reduce the risk of infection and damage to the GW that could occur with repeated use.

The 2 primary GW systems for ERCP are “short” and “long” systems. The 3 most common short systems are the RX system (Boston Scientific, Marlborough, Mass, USA), the Fusion system (Cook Endoscopy, Bloomington, Ind, USA), and the V system (Olympus, Center Valley, Pa, USA). These systems all allow locking (externally at the working channel and internally at the elevator) of a shorter GW (260-270 cm length), after which long devices such as sphincterotomes, balloon catheters, and stents can be advanced over the GW without the wire moving out of position. This allows the endoscopist to independently control the GW at the level of the working channel or the accessory port. Use of the short system can therefore help maintain ductal access and reduce procedure time by shortening the time needed for device exchanges. The long GW systems require exchange of accessories over the GW (for which the wire must be at least twice the length of the device) and generally require an assistant to maneuver the GW during device exchange. This long system allows countertension by the assistant while advancing devices over the GW, but the long length of the GW can lead to accidental contact of the GW with the floor, which can lead to its contamination. Relatedly, the long length of the wire can lead to the assistant having to juggle many tasks simultaneously, such as operating devices, injecting contrast, and maneuvering the wire while making sure the GW does not touch other surfaces.

Hybrid ERCP platforms using short GWs with long accessories can also be used successfully. This approach relies on the elevator lock to hold the GW during device exchange, as the endoscopy assistant ultimately loses control of the GW during both accessory removal and advancement.

In comparing the 2 systems, a prospective study found that use of a short system led to faster exchanges with equivalent ductal cannulation.⁵ This was echoed in a randomized trial that found faster device exchange times and stent insertion times with the short system.⁶ A randomized trial comparing endoscopist-controlled (short) wire use and assistant-controlled (long) wire use also found a significantly lower PEP rate (2.8% vs 9.3%) with the short system and equivalent biliary cannulation rates.⁷ Nevertheless, choice of a GW system depends on numerous factors including endoscopist preference and comfort level, costs, and resource availability.

In regard to GW diameter, several randomized trials have compared .035-inch GWs with .025-inch GWs in terms of the rate of successful biliary cannulation and adverse events.8, 9, 10 The largest study, an international multicenter study including 710 patients, found no difference in the rate of successful cannulation or the rate of PEP.⁸ Similarly, a meta-analysis found similar biliary cannulation rates (relative risk, 1.02; 95% confidence interval, .96-1.08) and rates of PEP (relative risk, 1.15; 95% confidence interval, .73-1.81) between the 2 GW calibers.¹¹ In regard to pancreatic duct access, 1 study found that the use of J-tipped GWs (RWHJ-2545SJ; Piolax Medical Devices, Inc, Kanagawa, Japan) led to significantly higher procedural success rates for pancreatic duct endotherapy compared with an angled GW (Visiglide; Olympus).¹²

Multiple GWs may be used simultaneously during a procedure, such as when 2 or more GWs are desired to maintain access to multiple sectoral biliary ducts (or a biliary and pancreatic duct) for subsequent intervention. The use of a double-GW technique is a relatively common practice, most commonly where an initial GW is placed and maintained in the pancreatic duct and a second GW is used to facilitate biliary cannulation.¹³ A double-GW technique can also be used for placement of 2 or more biliary stents (eg, hilar strictures) after parallel cannulation of several sectoral biliary ducts before stent placement.

Therapeutic EUS

EUS-guided transmural stent placement into the pancreaticobiliary tract is increasingly performed when conventional ERCP is not possible or fails. To accommodate these novel procedures, a variety of GWs have been used in therapeutic EUS procedures. It is important to note that a 19-gauge EUS needle will accommodate up to a .035-inch GW, whereas a 22-gauge EUS needle can only accommodate up to a .021-inch GW.

EUS-guided rendezvous technique

Although a variety of techniques for performing a biliary or pancreatic rendezvous procedure exist, the general principle includes EUS-guided puncture of the bile duct or pancreatic duct from the GI lumen, followed by antegrade advancement of the GW within the bile duct or pancreatic duct and into the small bowel through the major/minor papilla or a surgically created anastomosis. The GW is then coiled and left in place while the echoendoscope is exchanged for a duodenoscope or forward-viewing endoscope. The GW is then identified within the small-bowel lumen, and the procedure continues by using retrograde passage of accessories either alongside or over the rendezvous GW.

Focusing on the biliary rendezvous procedure, needle puncture can be performed into the left intrahepatic bile duct (typically transgastric) or the extrahepatic bile duct (most common) through the proximal duodenum or the second portion of the duodenum. Dilute contrast is typically injected to obtain a cholangiogram, followed by GW advancement through the needle into the small bowel. Long (450 cm), angled .025-inch or .035-inch GWs are typically used because angled wires facilitate maneuverability toward the distal duct and the long length allows removal of the echoendoscope over the GW. Although .021-inch and .018-inch GWs can be used (particularly with a 22-gauge needle), these are prone to kinking. Endoscopists can control GW advancement, but this may be challenging when holding the scope or needle in an unstable position. Studies have demonstrated higher rates of successful GW placement if needle puncture is performed in the second portion of the duodenum, where the echoendoscope is in a short position and GW manipulation is easier.14, 15, 16 Notably, the inability to manipulate the GW past the stricture or the major papilla represents the primary cause of failure during the rendezvous technique.^17,18

EUS-guided hepaticogastrostomy

With this technique, the left hepatic duct is punctured from the stomach under EUS guidance. After a cholangiogram is obtained, the GW is then advanced into the biliary tree and coiled in the common bile duct or right hepatic duct. Dilation of the hepaticogastrostomy tract is performed, followed by placement of a self-expandable metal stent. Several challenges may be encountered during this procedure. A long, angled .025-inch GW is commonly used because a primary anticipated challenge is manipulation of the GW to orient it toward the papilla or bilioenteric anastomosis. Additionally, use of a 19-gauge needle can be challenging because of its stiffness and lack of maneuverability. Alternately, a 22-gauge needle facilitates biliary access; however, .018-inch GWs have poor visibility with limited maneuverability because of a lack of stiffness. A novel .018-inch GW (Fielder; Olympus) has been developed for this indication, which includes a coiled tip to prevent the GW from adhering to the puncture needle, a polytetrafluoroethylene coating, and enhanced fluoroscopic visibility, with studies demonstrating high technical success rates.19, 20, 21, 22 GW control by the endoscopist has also been found to increase the technical success of EUS-guided hepaticogastrostomy when assistant-controlled GW insertion is unsuccessful.²³

An alternative method for EUS-guided hepaticogastrostomy is the use of a double-wire technique where a double-lumen cannula is inserted over a .025-inch GW placed during the initial needle puncture.^24,25 Once the double-lumen cannula is within the left hepatic duct, a preloaded .035-inch stiff GW is also advanced into the left hepatic duct. The presence of 2 wires in the left hepatic duct improves scope stabilization, supports device delivery, and provides a lifeline against technical failure; however, this approach requires tract dilation to accommodate the double-lumen cannula.²⁶

Drainage of walled-off collections

When performing traditional EUS-guided transmural drainage with double-pigtail plastic stents, a long GW has typically been used to facilitate exchange of multiple devices over the GW once needle puncture has been performed. Because recannulation of the walled-off collection with a GW poses a challenge after placement of the first double-pigtail plastic stent, a double-wire technique has been described with several devices such as double-lumen and triple-lumen catheters (Haber ramp; Cook Medical, Winston-Salem, NC, USA) to permit collection access with multiple GWs, thus facilitating placement of multiple stents without the need for repeat cannulation.27, 28, 29 Although the increasing use of electrocautery-enhanced lumen-apposing metal stents (LAMSs) has revolutionized EUS-guided transmural stent placement and reduced the need for a GW when the freehand technique is used, GWs are often used after the initial deployment of the LAMS. Long, angled GWs are preloaded into the stent catheter before LAMS deployment or advanced through the LAMS lumen after deployment to allow coiling within the target lumen/cavity for subsequent interventions. The GW can then be used for LAMS dilation (if necessary) and/or for placement of double-pigtail plastic stents in a coaxial fashion.

Related to the use of LAMSs, GWs are frequently used when performing EUS-guided gastroenterostomy. Initial GW advancement past the site of obstruction can facilitate placement of a catheter through which contrast can be injected, facilitating identification of the downstream lumen for LAMS placement.³⁰ Additionally, GW advancement into the target lumen through the LAMS deployment catheter (typically preloaded) can help salvage misdeployed LAMSs by allowing placement of a second stent.³¹

Luminal dilation and stent placement

A variety of GWs have been developed for primary use with rigid dilation devices (eg, Savary dilators, Cook Medical, Bloomington, Ind, USA) that are typically larger in diameter and composed of stainless steel with a coiled, flexible tip to facilitate atraumatic advancement past a stricture. These GWs have external markings that delineate the length of the GW within the patient, and their rigidity facilitates advancement of dilation devices in the esophagus. Dilation balloons will often come with a preloaded GW; however, the preloaded GW can be removed if the endoscopist chooses to work over a different GW.

With the development of through-the-scope esophageal self-expandable metal stents, fully covered and partially covered self-expandable metal stents can seamlessly be deployed throughout the GI tract. These stents are typically deployed over long GWs with a recommended diameter of .035 inches. Similarly, uncovered duodenal and colonic stents are typically deployed through the scope over a long .035-inch GW to avoid losing GW access. Stents designed for deployment over a GW but not through the scope, such as conventional esophageal self-expandable metal stents, can be deployed over a .035-inch GW or a more rigid GW (eg, Puestow or Savary-Gilliard GW [Cook Medical, Bloomington, Ind, USA]), with preference given to stiffer GWs to facilitate advancement of the stent delivery catheter, especially in cases of distal esophageal strictures.

Upper GI tract

In addition to the indications listed above, GWs can be used in the upper GI tract for placement of feeding tubes, removal of foreign bodies, and advancement of tubes for balloon tamponade (Blakemore or Minnesota tubes).^32,33 Additionally, GW advancement can facilitate endoscope advancement past strictures, Zenker’s diverticulum, and other tortuous or abnormal anatomy within the GI tract. This may be particularly useful when the endoscope cannot be advanced past the upper esophageal sphincter or when using a side-viewing endoscope (eg, duodenoscope).³⁴

Applicable to both the upper and lower GI tract, GWs can aid placement of over-the-scope (OTS) clipping devices by overcoming the impairment of endoscopic visibility that often occurs after attaching these larger clips onto the endoscope. After attaching the OTS clipping device, the endoscope can be advanced over the GW to the area of interest immediately before OTS clip deployment. The endoscope with the OTS clip can then be deployed at the treatment site.^35,36 Stiffer wires (eg, GWs with “super stiff” or “extra stiff” designations) carry the advantage of having more rigidity, thus reducing the risk of buckling when passing stents or feeding tubes past the stomach.

Lower GI tract

Similar to the upper GI tract, GWs can be used in the lower GI tract for performing dilation, deploying stents, and facilitating colonoscope advancement. Long GWs are also typically used for placement of decompression tubes within the colon in patients with colonic obstruction or pseudo-obstruction, with or without the use of fluoroscopy.

Safety

Ductal perforation, commonly referred to as a type III perforation, represents the most common adverse event related to GW use in ERCP.^37,38 A meta-analysis found that ERCP-related perforations remain uncommon (.39%), of which GW-related perforations accounted for 16%.³⁹ Importantly, none of the GW-related perforations required operative management. Loop formation by the GW is believed to protect against ductal perforation, with ex vivo studies showing considerable differences in loop formation ability among different GWs.² A novel .025-inch GW (MICHISUJI; Kaneka Medical, Osaka, Japan) has an extremely flexible tip and high torqueability because of its high surface hydrophilicity.⁴⁰ This allows easy GW deflection and loop formation, allowing deeper access into the duct of interest, and increases GW stability for accessory use. Of note, the creation of loops during GW manipulation can result in entanglement and knot formation that can be problematic when advanced past a stricture.41, 42, 43 Notably, although hydrophilic-tip GWs are noted to pose a greater risk of perforation in coronary vessels, this increased risk has not been found in the pancreaticobiliary tract.^44,45

In performing therapeutic EUS, shearing of the GW represents a potential adverse event where the sheath or coating of the GW can be sheared off the GW from contact with the sharp beveled needle tip, resulting in leaving a foreign body in the pancreaticobiliary tract that can serve as a nidus for infection.^23,46, 47, 48 Shearing is most likely to happen when the GW is pulled back into the needle after having reached the periphery of the duct, which can be prevented by gently withdrawing the needle slightly while maintaining access.⁴⁹ Specific access needles have been developed containing a blunt-ended sheath that remains within the duct after the sharp stylet is withdrawn. These were designed to prevent GW shearing; however, constant GW awareness is necessary with the use of access needles to prevent and identify GW shearing, particularly in the pancreatic duct because of its narrow diameter.⁵⁰ In ERCP, fracturing of the GW has also been described, typically occurring after torqueing the wire with a torque device.^51,52

PEP, the most common adverse event related to ERCP, can occur with pancreaticobiliary GW use but remains outside the scope of this report and is discussed at length in a separate American Society for Gastrointestinal Endoscopy document focusing on prevention strategies for PEP.⁵³ Of note, coated GWs commonly used in endoscopy contain insulation against transmission of short circuits and induced currents.⁵⁴ Use of electrocautery, however, should be cautioned if the GW appears to be visibly damaged.

Financial Considerations

Most GWs are single-use (disposable) items, with the exception of certain stainless steel GWs used to facilitate endoscopic dilation or help advance devices for endoscopic therapy. When reusable GWs are used, there is a facility cost (practice expense) involved with high-level disinfection or sterilization, repackaging, and storage. More recently, there has been a trend toward using stainless steel GWs that are also single use as an additional measure toward infection control. Some technically challenging procedures may require use of multiple GWs of different types in the same procedure in an attempt to facilitate a successful outcome, which adds to the cost of the procedure. In addition, fluoroscopy use may be needed for passage of certain GWs in some procedures, thus further elevating overall procedure cost.

The costs associated with GW use should be weighed against the safety and efficacy that these devices impart to endoscopic procedures. In general, GW pricing and costs will vary based on design features, materials involved, and the type of procedure for which it was developed. In addition, regional, market, and contractual variables affect device pricing. As shown in Table 1, the costs of GWs have a broad range, with specialty GWs being the most expensive. Cost awareness is important for the endoscopist in choosing which GW to use because specialty wires are not essential to every case and cheaper wires suffice for many indications.

The environmental impact of disposable devices such as GWs cannot be ignored given that the healthcare industry contributes to 8% of greenhouse gas emissions in the United States, and use of disposable supplies including GWs during endoscopic procedures generates 42,000 tons of waste a year.⁵⁵ Barriers to developing reusable GWs include the lack of an effective method for sterilization and damage incurred to GWs (particularly coated GWs) with each use, and further development will be needed before widespread consideration of reusable GWs.

Disclosure

The following authors disclosed financial relationships: V. S. Akshintala: Board member for Origin Endoscopy Inc; consultant for Dragonfly Endoscopy Inc; research support from Abbvie, Boston Scientific Corporation, and Medtronic; travel compensation from Mauna Kea Technologies, Inc; food and beverage compensation from Mauna Kea Technologies, Inc, Boston Scientific Corporation, and AbbVie Inc. D. Chen: Food and beverage compensation from Ambu Inc. Y-I. Chen: President of Chess Medical; consultant for Boston Scientific Corporation. K. K. Das: Patent-holder with Interpace Biosciences; food and beverage compensation from Medtronic, Inc. A. Kahn: Consultant for MiMedx. G. Mishra: Consultant for Pentax of America, Inc and Cook Medical LLC; travel compensation from Pentax of America, Inc; food and beverage compensation from Pentax of America, Inc, Cook Medical LLC, Ambu Inc, Boston Scientific Corporation, and Wilson Cook Medical Incorporated. V. Raman Muthusamy: Consultant for Medtronic and Boston Scientific Corporation; research support from Boston Scientific Corporation; stock options/equity in Capsovision; Advisory Board for Endogastric Solutions and Motus GI; travel compensation Boston Scientific Corporation; food and beverage compensation from Boston Scientific Corporation, Steris Corporation, Medtronic, Inc, Apollo Endosurgery US Inc, Endogastric Solutions, Inc, Cook Medical LLC, Pentax of America, Inc, and Olympus America Inc. J. V. Obando: Shareholder with Surgenly LLC. F. U. Onyibma: Food and beverage compensation from Endogastric Solutions, Inc and Medtronic, Inc. S. Pawa: Consultant for Boston Scientific Corporation. T. Rustagi: Consultant for Boston Scientific Corporation; food and beverage compensation from Boston Scientific Corporation and Merit Medical Systems Inc. S. Sakaria: Food and beverage compensation from AbbVie Inc. G. Trikudanathan: Consultant for Boston Scientific Corporation; food and beverage compensation from Boston Scientific Corporation. R. J. Law: Consultant for Conmed Corporation, Boston Scientific Corporation, Medtronic USA Inc, and Olympus America Inc; royalties from UpToDate; food and beverage compensation from Olympus America Inc, Boston Scientific Corporation, and Ethicon Inc. All other authors disclosed no financial relationships.