Ureteroscopy (URS) is one of the most commonly performed procedures today and has become the standard of care in treating many upper urinary tract diseases. Urologists need a thorough understanding of the armamentarium of ureteroscopic equipment and adjuncts at their disposal in order to safely execute this endoscopic procedure. The goal of this chapter is to provide an overview of the tools for URS.
Preoperative Preparation and Planning
Careful preoperative preparation and planning are critical keys to carrying out a successful ureteroscopic procedure. Having access to all the potential tools that you may need is crucial. The patient should have been counselled to the type of procedure, its success rate, and potential complications. Specifically, URS offers a high success rate for stones up to 2 cm in diameter. Alternatives such as shockwave lithotripsy (SWL), percutaneous nephrolithotomy (PNL), or observation of the stone should also be discussed so that patients can make informed treatment decisions. URS can offer similar results to SWL for smaller and more mid to distal ureteral stones but higher rates of success when treating renal and proximal ureteral stones. Stones larger than 10 mm in the lower pole have a higher rate of success with PNL than URS or SWL. Patients should be aware that if the ureter is too tight and it is difficult to insert the ureteroscope that they may only end up receiving a ureteral stent to passively dilate the ureter for a subsequent procedure. When a stone appears very impacted (particularly in the upper ureter), patients should be made aware that if retrograde access cannot be achieved that they may require percutaneous nephrostomy tube insertion and future antegrade URS. Other complications that warrant mention include ureteral perforation, ureteral avulsion (rare), and future ureteral stricture (<1%). Patients must understand that they may receive a ureteral stent at the end of the procedure and all of the symptoms that it entails. If they are not stone free, they may require further surgery.
Patients should be assessed by the anesthesia team preoperatively and prepared for general anesthesia, although it is possible to carry out URS under spinal anesthetic or even neuroleptic sedation in some cases. Urine should be sterile, and if the patient is suspected of having urosepsis, decompression of the system with either a ureteral stent or nephrostomy tube with a complete course of antibiotics is needed before definitive treatment of the stone. Preoperative antibiotics suitable to the antibiograms specific to your region should be given.
Patient Positioning and Equipment Positioning
Patients are placed in the lithotomy position, although supine or lateral decubitus positions can be used for flexible URS cases. Care should be taken during positioning to avoid any neuropathies and unintended injuries by being liberal with padding and conscious of arm position. The patient should be on a table that is radiolucent. Fluoroscopy should be available with either a fixed “all-in-one” fluoroscopy table or a portable C-arm unit. The fluoroscopy unit should be placed on one side of the patient; the other side houses the video tower necessary to view the procedure. The surgeon can either sit or stand, and the table height should be adjusted accordingly to optimize ergonomics. The laser console should be positioned as close as possible to the surgeon and patient, preventing any long lines of laser fiber that could be inadvertently pulled on by operating room (OR) staff walking through the room. This is also dangerous to the ureteroscope if the laser is being activated and a staff member becomes entangled in the fiber and pulls it back into the working channel, thus damaging the ureteroscope. An intravenous pole housing irrigation (typically normal saline) is needed, and there should be easy access for nursing staff to change these bags. Two bags can be used—one under gravity, typically used during ureteral access via cystoscopy, and another in a pressure bag to provide pressure irrigation through the small diameter ureteroscopes if so desired. Handheld and foot-controlled pedal irrigation devices are also available to provide pressure irrigation. Be careful to limit the pressure to the minimal amount required for good endoscopic visualization because excessive irrigation pressure can lead to ruptured fornices, pyelotubular backflow, and potentially more postoperative pain for the patient.
Operative Technique: Instruments Required
A list of required instrumentation is outlined in Table 40.1 .
|Ureteral access||Guidewires |
|Ureteral catheters |
|Ureteral dilators |
|Ureteral access sheaths |
|Ureteroscopes||Semirigid ureteroscope |
|Flexible ureteroscope |
|Intracorporeal lithotriptors||Holmium:YAG laser|
|Baskets and stone retrieval devices||Baskets |
|Ureteral occluding devices||Antiretropulsion devices|
|Postoperative drainage||Ureteral stents|
Both rigid and flexible cystoscopes should be available in order to gain access to the bladder and ureter. Rigid cystoscopes are used in most cases, and flexible cystoscopes are sometimes needed in men with large, high-riding prostates or when URS is performed in a position other than dorsal lithotomy.
A multitude of guidewires need to be available to safely access the ureter and navigate any potential ureteral obstructions. A regular polytetrafluoroethylene- (PTFE-) coated wire or hybrid wire can be used for initial access. Hybrid wires combine the advantage of a hydrophilic tip with a PTFE shaft coating. The hydrophilic tip can help ease the guidewire past obstructions, but a PTFE-coated shaft is easier to work with than hydrophilic shafts, which are very slippery. Furthermore, the nitinol core of hybrid wires means they are virtually unkinkable. Stiffer guidewires can be used to help straighten out tortuous ureters or are sometimes necessary for use with ancillary instruments such as advancement of a ureteral access sheath or sequential dilation. Guidewire tips can be straight or angled. Straight tips are often easier to insert in the ureteral orifice. Angled tips are helpful for bypassing ureteral obstructions.
Straight ureteral catheters measure 5 or 6 Fr and are helpful for performing retrograde pyelograms. Inserting this through the working channel of the rigid cystoscope helps stabilize the guidewire in the working channel for insertion into the ureteral orifice. Angled ureteral catheters in combination with an angled hydrophilic tip guidewire are very helpful for probing and inserting catheters past obstructions. These catheters should be available depending on each case and the degree of obstruction. They can also be helpful for gaining access to reimplanted ureters, which can often be challenging.
Ureteral dilators are sometimes necessary to dilate strictures and tight ureters. Dilators come in two main forms: sequential dilators and balloon dilators. Sequential dilators are inserted over a guidewire, typically with a stiff shaft, and gradually increased in diameter until the ureter is wide enough to accommodate the ureteroscope. Insertion of these dilators should be monitored with fluoroscopy with care taken to ensure proper guidewire placement before each pass of the dilator. Balloon dilators come in various lengths and diameters. The low-profile balloon on the catheter is inserted over the guidewire after a retrograde pyelogram has been performed to outline the area of narrowing or stricture. There are radiopaque markers on the proximal and distal ends of the ureteral balloon. The center of the balloon should be positioned over the area of narrowing using fluoroscopy. A syringe-insufflator (filled with diluted radiocontrast) specialized in generating high pressure is then used to inflate the balloon above its nominal pressure but not more than the maximal burst pressure. Care should be taken to use the proper diameter balloon depending on the location of the ureter and the degree of stricture. Balloons come in 4-, 5-, 6-, and 7-mm diameters, which equal a range of 12 to 21 Fr. Generally, the larger balloon sizes should be avoided in the thinner, more delicate areas of the ureter—the proximal ureter and ureteropelvic junction (UPJ). The ureter is thicker and more vascular down toward the bladder and can accommodate larger balloons. One-step dilation can also be achieved by inserting a ureteral access sheath. Care should be taken to use the proper diameter ureteral access sheath that will not damage the ureter. It should be stressed that if the entire ureter is too tight to accommodate the ureteroscope, the most atraumatic method of ureteral dilation is insertion of a ureteral stent, abandoning the procedure and passive dilation over a period of time. There is no specified minimum time for ureteric stenting to achieve dilation, but certainly 7 days or greater produces a nicely dilated ureter that easily facilitates URS if no strictures are present. “Prestenting” the patient before another definitive URS is the safest method of dilation to avoid ureteral injury and also improves stone free rates in patients with stones larger than 10 mm. Even so, when a single procedure can be performed safely and effectively, “prestenting” can be avoided to spare the patient from repeat procedures and anesthetics.
Ureteral Access Sheaths
Ureteral access sheaths (UAS) can be used to facilitate flexible URS for renal and proximal or midureteral stones, particularly when repeated entries of the ureteroscope is necessary such as when stone fragments are retrieved from the kidney. They come in a variety of diameters and are denoted by two sizes. The first size denotes the inner diameter, and the second number is the outer diameter. Smaller sheaths may produce less pressure on the ureteral wall and are easier to insert but may not enable passage of larger diameter ureteroscopes or basket retrieval of larger fragments. The larger sheaths fix these shortcomings but at an increased risk of ureteral damage. Other advantages in using UAS is that they decrease renal perfusion pressures and increase irrigation flow, thus improving endoscopic visibility. A large study showed no difference in stone free rates when using UAS. UAS may be associated with superficial urothelial injuries in the majority of patients, but most are self-limiting without long-term sequelae. Stenting after using a UAS reduces postoperative patient pain and emergency department visits. The length of the UAS is determined by the location of the pathology and gender of the patient. Shorter UAS are typically used in females, and longer ones are necessary in males because of their longer urethras. Shorter UAS can be used in mid to proximal ureteral stones, and longer ones will accommodate pathology in the kidney. Having the most proximal end of the UAS in the renal pelvis will likely result in the greatest benefit to reducing renal pressure but may affect the deflection of the ureteroscope into the lower pole and may also impair visibility in hydronephrotic kidney’s where relatively increased irrigation pressures may help pelvicalyceal distension. In these cases, the UAS may be withdrawn slightly to accommodate the curvature of the flexible ureteroscope and to minimally increase pressure. When the UAS is below the UPJ, care must be taken during basket retrieval because the UPJ will be exposed and, if narrow, can result in damage if the stone is too large for extraction. Insertion of a UAS should always be performed over a guidewire with fluoroscopic monitoring and insertion should never require great force. If the UAS is not advancing, direct visualization should be undertaken to rule out an obstructing ureteral stone, obstruction, or stricture.
Ureteroscopes come in various lengths and sizes. There are two major differences: semirigid and flexible, which are further subdivided into digital and fiberoptic. The semirigid ureteroscopes come in shorter or longer versions and generally have larger working channels, provide better optics compared to fiberoptic ureteroscopes, and are more robust and less prone to damage compared with flexible ureteroscopes ( Fig. 40.1 ). Pathology at or below the level where the ureters cross the iliac vessels is easily reachable with semirigid ureteroscopes. In many women and some men, the semirigid ureteroscope can be used to reach the renal pelvis, but care must be taken not to force the ureteroscope and avulse the ureter in what is known as a “scabbard” avulsion.
Flexible ureteroscopes offer the greatest reach and maneuverability with deflection up to 270 degrees in both directions ( Fig. 40.2 ). Fiberoptic and digital flexible ureteroscopes with variable shaft diameters, working ports, and tip configurations are available and continue to evolve to facilitate easier access to the ureter and lower pole. Larger, blunt-tip digital ureteroscopes have made way for smaller, bevelled-tip digital ureteroscopes with smaller shaft diameters. Digital ureteroscopes confers much higher resolution than fiberoptic scopes ( Fig. 40.3 ). The repair rate and success rate of stone treatment have not been shown to be any different between flexible and digital ureteroscopes. It is recommended to have at least a small percentage of one’s flexible ureteroscope armamentarium to consist of fiberoptic flexible ureteroscopes because there are some instances when digital ureteroscopes may not be able to access the ureter or lower pole properly to carry out the proposed procedure.