3. Single Operator Cholangioscopy
Boston Scientific (Boston Scientific Corporation, USA) developed a fibreoptic cholangioscopy platform in 2007 called SpyGlass™ that revolutionized single operator cholangioscopy. This system included a cholangioscopy catheter that could be introduced through the working channel of a duodenoscope (over a guidewire) and strapped onto the side of the duodenoscope using a silastic strap, a pump to provide irrigation (sterile saline/water) and disposable devices that could be introduced through an instrumentation channel on the cholangioscope. The cholangioscope itself was a 10 Fr disposable 4-lumen catheter (Cholangioscope) with a 0.9 mm channel for the fibreoptic probe, a 1.2 mm channel to pass instruments/accessories and two 0.6 mm irrigation channels. A 3 Fr disposable biopsy forceps (SpyBite™) was available with the system and could be passed down the cholangioscope. Fibres to facilitate electrohydraulic lithotripsy (EHL) or laser lithotripsy could be additionally passed down the cholangioscope. The cholangioscope had 4-way tip deflection that facilitated manoeuvrability within the pancreaticobiliary system. The fibreoptic system was upgraded to a digital SpyGlass™ DS in 2007 and more recently, a further upgrade to a 3rd generation system called the SpyGlass™ DS II was launched . The SpyGlass™ DS and DS II systems are single-use 10 Fr cholangioscopes and represent a significant improvement in image resolution in comparison to the legacy fibreoptic system. These digital cholangioscopes have retained the basic features of the legacy cholangioscope, with two irrigation channels and an instrumentation channel, and have a simple ‘plug-and-play’ setup onto a processor. Boston Scientific partnered with Northgate Technologies Inc (USA) in 2017 to distribute Northgate’s EHL system called Autolith™. The Autolith™ system delivers energy to facilitate EHL through a 1.9 Fr disposable probe. In 2018, Boston Scientific released a retrieval basket and snare with the SpyGlass™ DS II system.
The set up and technique described in this chapter relates to the digital SpyGlass platforms.
Please see online Video A that demonstrates the set-up, monitoring and use of the SpyGlass single operator cholangioscopy system.
The digital cholangioscope is generally inserted over a 450 cm guidewire that is initially placed in the pancreaticobiliary system at ERCP. Standard ERCP techniques are used for cannulation and duct access following which ‘long-wire’ (450 cm guidewire) access is achieved for biliary endotherapy. A biliary sphincterotomy is generally necessary to facilitate the advancement of the cholangioscope into the bile duct. A sphincterotomy additionally mitigates against increases in hydrostatic pressures in the biliary system by allowing flow around the cholangioscope. The cholangioscope is supplied in a sterile box and is assembled by plugging its cable onto the SpyGlass DS processor. The cholangioscope has an irrigation cable which is connected onto an irrigation pump generally delivering sterile saline and a separate suction cable with a three-way connector, which can be connected to a suction system. The processor and monitor are delivered on a dedicated stack that houses the Autolith™ generator and the cabling for the SpyGlass system.
The cholangioscope is advanced over the guidewire into the biliary system and is strapped onto the side of the duodenoscope. The cholangioscope sits just underneath and slightly to the right of the duodenoscope instrument channel. The duodenoscope position is stabilised once the cholangioscope is advanced out of the duodenoscope. Plugging the cholangioscope immediately generates a digital image on the SpyGlass monitor with the light on the cholangioscope activated. The light is generally turned off in order to reduce glare and facilitate visibility whilst advancing the scope into the bile duct. Advancement of the cholangioscope into the distal bile duct is generally easy over a guidewire, although freehand cannulation across a wide, sphincterotomised papillary orifice is also feasible. The cholangioscope has a single lock for its wheels, which can be applied to stabilise the tip and prevent excessive deflection. Advancement into the proximal bile duct is facilitated by a combination of insertion of the cholangioscope, adjustment of wheels and irrigation using the foot pump to aid visualisation. Once the cholangioscope is stabilised adjacent to a target (stone, stricture, etc.), the guidewire is removed to facilitate the deployment of accessories for therapy. Deep sedation or anaesthesia is generally required to facilitate cholangioscopy and lithotripsy.
Lithotripsy or fragmentation of stones is carried out using electrohydraulic lithotripsy or laser lithotripsy.
Electrohydraulic Lithotripsy (EHL)
Please see online Video cases 1–7 and 11 that demonstrate the use of EHL to fragment stones in the bile duct.