Duodenoscopes
The standard endoscope for ERCP is the sideviewing duodenoscope, equipped with a tip with four-way angulation capability, a side-positioned air/water nozzle, an instrument channel, and a forceps elevator adjacent to the instrument channel outlet that allows fine linear instrument position changes facilitating cannulation and placement of various devices. Instrument channel diameter ranges from 2.2 to 5.5 mm. Duodenoscopes with 4.2 mm internal channel allowing to place biliary endoprostheses (10-11.5 Fr circumference) are the most used. Pediatric duodenoscopes with a 2.2 mm channel are available for examination in infants, while largest instrument channels (>5 mm) are found in so-called "mother/baby" scope system usedfor choledochoscopy and pancreatoscopy. However this system is difficult to manipulate and is now rarely used [1].
In certain situations where a traditional duodenoscope is not suitable (e.g., in patients with a Billroth II or a Roux-en-Y reconstruction), a forward-viewing endoscope may be tried instead [2]. Conventional endoscopes however provide a limited visualization of the ampullary region and are limited with respect to control of accessories during cannulation due to the absence of elevator. In recent years, infections due to multidrugresistant organisms (MDROs) have become a concern in health care, including in gastrointestinal endoscopy. Cases and serial outbreaks of MDROs infections associated with ERCP have been published from different countries from 2010 [3]. All the processes of cleaning, disinfection, and sterilization of duodenoscopes have been analyzed featuring different issues [4].
Major manufacturers developed tools to prevent infections such as detachable disposable distal cap. Post-procedure reprocessing is performed by detaching the disposable distal cap and cleaning and disinfecting the tip of the scope [5]. In addition, new adaptors that can be attached to the tip of the duodenoscope to inject a cleaning solution have been developed
Echoendoscopes
Endoscopic ultrasonography (EUS) combines endoscopy and intraluminal ultrasonography. The new electronic instruments are connected with processors with considerable digital capabilities. Therefore, the technical peculiarities of the endoscopes of the same brand (i.e., NBI, FICE, Hi-scan) are contemporary available with the technical features of the most modern ultrasounds equipment (Doppler, power Doppler, color Doppler, tissue harmonic echo [THE], contrast harmonic EUS [CH-EUS], elastography, etc.).
The instruments for endoscopic ultrasound evaluation can be divided in:
-radial echoendoscopes for diagnostic purposes, -linear echoendoscopes for diagnostic and interventional purposes.
Radial echoendoscopes consist of electronic radial-array transducers that orient the individual piezoelectric elements around the distal tip in a 360° radial array, producing an image in a plane perpendicular to the long axis of the echoendoscope that is very similar to the images provided by computed tomography. Radial-array echoendoscopes are used only for diagnostic EUS examinations because tissue sampling and therapeutic interventions are not possible due to the lack of visualization of needle or other devices track.
Linear echoendoscopes provide a plane of imaging parallel to the long axis of the scope with an image format that is similar to that obtained with transabdominal ultrasonography; only this type of probe allows real-time visualization of needles and other accessories introduced through the operative channel of the echoendoscope [6][7][8]. It allows to perform fine-needle aspiration or biopsy (FNA or FNAB), stent delivering, drainage, and locoregional treatments (i.e., celiac plexus block and neurolysis).
Three major manufacturers (Olympus, Pentax, Fujifilm) produce echoendoscopes.
Table 4 .
Paolo Bocus
