Antegrade ureteroscopy (URS)

Antegrade URS refers to percutaneous approach to the ureter via the kidney. This is usually done when retrograde ureteric access is difficult (such as in urinary diversion) or retrograde ureteroscopy is not possible.


Clinically insignificant residual fragments (CIRF)

CIRF refers to clinically insignificant fragments post-endourological treatment usually defined as symptomatic, non-infectious fragments which can be observed. There is no consensus on the size of these fragments which is usually accepted as fragments of ≤2 mm size.


Diverticular stones

It refers to the stones in a cystic cavity of the kidney lined by the urothelium, connected to the pelvicalyceal system via a narrow neck.


It is a technique that uses low pulse energy and high frequency with long pulse duration during laser lithotripsy to dust the stone. This technique utilizes a high-powered laser to ablate stones into dust.


ECIRS (Endoscopic combined intrarenal surgery)

It is a synergic approach combining retrograde flexible ureteroscopy and PCNL to treat large or complex renal stones with the aim to improve stone free rates. This is usually performed in ‘modified supine’ position.



It is a technique that uses high pulse energy and low frequency with short pulse duration during laser lithotripsy to break the stone into fragments.


Glue-clot technique

It is an endourological technique described to efficiently remove small fragments after stone treatment. 10ml of autologous venous blood taken in a syringe is injected in the calyx with fragments. After 5-10 minutes, once the blood is washed with saline, the glue-clots with stone fragments within it are retrieved with a basket.


Intrarenal pressure

It refers to the pressure in the pelvicalyceal system during ureteroscopy. While the normal physiological pressure is 10mmHg, this can rise during ureteroscopy causing pyelovenous, pyelosinus and pyelolymphatic backflow. Forced irrigation pressures also increase the risk of infective complications.


It is used to maintain the vision while performing ureteroscopy. Saline is the standard irrigation, which is usually pressurized to get adequate flow.


Laser fiber

It is the energy source used to break the stone and varies in its diameter, shape of the tip, effect on ablation of calculi and its degradation.

Laser settings

Laser lithotripters allow the control of total power output by controlling the pulse energy and pulse frequency.

Total power(W) = Pulse energy (Joules) x Pulse frequency (Hz)

By adjusting these parameters for dusting, the energy can range from 0.2-0.6 J with a frequency of 30-80 Hz; and for fragmentation the energy can range from 0.6 J-2 J with a frequency of 5-12 Hz.

Lower pole stones

It refers to the stones in the lower part of the pelvicalyceal system (lower calyx). The stones can either be treated in-situ or relocated to the upper pole calyx or renal pelvis for fragmentation.


Medical expulsive therapy (MET)

MET refers to medical therapies (alpha-blockers) to facilitate passage of ureteric stones. While its clinical benefit is currently controversial, it might be useful in distal ureteric stones >5mm.

Micro, Ultra-mini and Mini PCNL

These are new minimally invasive PCNL techniques using miniaturised instruments to decrease complications. While there is no formal agreement, standard PCNL refers to tract size >22Fr, Mini PCNL for a tract size between 14-20Fr, Ultra-mini PCNL for a tract size between 11-13Fr and micro PCNL for tract size between 5-8Fr.



It is similar to popcorning technique but uses a lower pulse energy resulting in finer fragments.


It is a technique that uses high pulse energy and high frequency with long pulse duration to produce small fragments.

Port seal

It is placed on the working channel of the ureteroscope, consisting of an O-ring, which allows using the instrument channel without causing any leaks whilst preserving the irrigation flow.


It is the insertion of a ureteric stent either electively or in an emergency situation prior to ureteroscopy, which is performed at a later date. It is usually done in difficult retrograde access for ureteroscopy either due to anatomic abnormalities, narrow ureteric lumen, tortuous ureter or previous instrumentation. Elective or planned ureteroscopy is subsequently done after a few weeks.

Prone and supine PCNL (percutaneous nephrolithotomy)

‘Prone PCNL’ refers to posterior renal access with the patient turned into prone position for PCNL procedure. ‘Supine PCNL’ refers to access with patient in supine position with a slight ipsilateral flank tilt based on individual patient characteristics and operating surgeon preference.



It refers to proximal migration of the stone during laser lithotripsy, thereby reducing the efficacy and increasing the operating time duration. High pulse energy and short-pulse mode increases retropulsion.

RIRS (retrograde intrarenal surgery)

RIRS refers to endoscopic surgical intervention within the kidney using the ureteroscope


Safety wire

It is the guidewire left in place before doing the ureteroscopy and often helps to keep the ureteric orifice open aiding passage of the ureteroscope.

Stone extraction devices

It refers to the stone graspers, baskets and forceps used to extract stone fragments.

Stone free rate (SFR)

SFR refers to treatment success and whether the stone(s) or all fragments have been successfully removed. There is no consensus on whether they should be completely stone free or whether small fragments (≤2 mm) are acceptable. Similarly, the timing and type of imaging modality for accessing SFR is not standardised.


Ureteral access sheath

It is a 2-piece hydrophilic device consisting of a sheath and the internal dilator. It is inserted over the working wire under fluoroscopic control and the inner dilator can be removed once the sheath is in put in place.

It comes in various diameters (9F – 14 F internal diameter; 11F – 17.5 external diameter) and lengths (20-55 cm).

Ureteral catheter

It is used for retrograde pyelogram (RPG) or for positioning of guidewire in the ureter or to obtain urine sample from pelvicalyceal system for cytology/culture.

Ureteroscopy (URS)

It is an endoscopic procedure to examine the ureter and/or kidney using a ureteroscope.


Working/Navigating guidewire

It is the second guidewire inserted via the ureteroscope and used for navigating, enabling the passage of ureteroscope.