Since 2006, the digital optics technology has represented the next step in the development of endoscopy with a distal sensor. Studies have showed that the better image quality provides a higher precision for diagnosis, treatment, and a shorter procedure time (Fig. 8.3) [11].

The first ureteroscopes to use digital technology include was Gyrus-ACMI DUR-D Invisio, Karl Storz with the Flex-XC, the Olympus the URF-V and URF-V2, and the Richard Wolf Boa and Cobra Vision. These new ureteroscopes integrate a digital camera and light source in a single plug and play device. The principal disadvantages with the digital generation are that the distal tip diameter are slightly greater than the equivalent standard fiber optic ureteroscopes (Fig. 8.4). Nevertheless, the digital generation is now considered the gold standard in term of image quality.

All digital ureteroscopes by Karl Storz, Gyrus-ACMI and Richard Wolf use a Complementary Metal Oxide Semiconductor (CMOS) imaging sensor as a digital camera and a light-emitting diode (LED) as the light source. CMOS is a generic term for the process used to produce these image sensors, along with a multitude of other semiconductor items such as computer RAM processors like those from Intel and other manufacturers. CMOS image sensors can be made in the same fabrication as these other items, with the same equipment.

Olympus has introduced the URF-V incorporating a charge-coupled device sensor (CCD). Interline Transfer CCD consists of many Metal Oxide Semiconductor (MOS) capacitors arranged in a pattern that can capture and convert light photons into electrical charge, storing this charge before transferring it for processing by supporting chips. When recording color information, a color filter is placed over each light receptor making it sensitive to only one light color. This gives a value for one color at each pixel, and the surrounding pixels can provide eight more values, four each for the two remaining colors from which they may be interpolated from the original pixel. After the exposure is complete, the charge is transferred row by row into a read-out register, and from there to an output amplifier, analog/digital converters and on for processing. This row-by-row processing of the CCD’s light data is where the sensor gets register and the rows behind it are each shifted one row closer to the register. After being “read-out,” the charge is released, and the register is empty again for the next charge. CCDs rapidly attain high image quality but require a manufacturing process which is different from that used for manufacturing other computer chips such as processors and RAM. This means that specialized CCD fabrications have to be constructed, and they cannot be used for making other components, thereby making CCDs more expensive.

Moreover, the Olympus URF-V incorporates another new technology: the narrow band imaging (NBI) function. NBI is an optical image enhancement which narrows the bandwidth of the light production of the Olympus Exera II system. This narrow band of light is greatly absorbed by haemoglobin and penetrates only the surface of tissue increasing the visibility of capillaries and other delicate tissue surface structures by enhancing the contrast between the two. As a result, under NBI, capillaries on the surface are displayed in brown and veins in the sub-surface are displayed in cyan on the operating monitor. This technology is principally used in the detection or recurrence of urothelial tumors of the bladder or upper urinary tract. One of the current authors (OT) has demonstrated that NBI has the potential to improve the detection/recurrence of upper tract urothelial tumors by 22.7 % comparing to white light (Fig. 8.5) [12].

In 2009, the PolyScope by Lumenis became available. This is a disposable, modular flexible ureteroscope with a 70 cm working length and a distal tip size of 9.6F. It has a single-side active deflection of 180°, and the working channel is 3.6F [13]. Currently, more studies are needed to demonstrate the efficiency and cost-effectiveness of this device though it does appear to be more difficult to manipulate than the usual flexible ureterorenoscopes.

Getting ureteral access and reaching the proximal ureter or the renal pelvis can sometimes be challenging. Thus knowing alternative access methods to assist the endourologist is essential.