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  • Ureteroscopy and Laser Lithotripsy

    About the Authors

    Jonathan E. Kiechle, MD, Matthew J. Maurice, MD, and Lee E. Ponsky, MD, FACS

    Center for Urologic Oncology & Minimally Invasive Therapies, Urology Institute, University Hospitals, Case Medical Center, Case Western Reserve University School of Medicine

    Jonathan E. Kiechle, MD

    Jon is a second-year Urology resident at University Hospitals Case Medical Center, Case Western Reserve University School of Medicine, in Cleveland, Ohio. He was born and raised in Detroit, Michigan. He received his Bachelor of Arts degree in History from the University of Notre Dame in 2007 and his medical degree from Georgetown University School of Medicine in 2011. He anticipates completing residency in 2017, at which time, he plans to pursue further specialization in urologic surgery.

    Matthew J. Maurice, MD

    Matt is a fourth-year Urology resident at University Hospitals Case Medical Center, Case Western Reserve University School of Medicine, in Cleveland, Ohio. He was born and raised in Chicago, Illinois. He received his Bachelor of Science degree in Biology from Saint Louis University in 2005 and his medical degree from Northwestern University Feinberg School of Medicine in 2009. He is currently performing a year of dedicated research as part of his residency training. He anticipates completing residency in 2015, at which time, he plans to pursue further specialization in urologic surgery. His interests include: minimally-invasive surgery, oncology, reconstruction, and surgical innovation.

    Lee E. Ponsky, MD, FACS

    Dr. Ponsky received his B.A. from University of Rochester and his Doctor of Medicine degree from Case Western Reserve University School of Medicine. He began his training in Urology at the Cleveland Clinic and completed his residency and extended his training to do a research fellowship in urologic oncology, followed by an additional fellowship in advanced urologic laparoscopy and endourology. In 2005, Dr. Ponsky joined the faculty at University Hospitals, Case Western Reserve University School of Medicine, and is currently an associate professor of Urology and holds the Leo and Charlotte Goldberg Chair in Advanced Surgical Therapies, he is the Director Urologic Oncology & Minimally Invasive Therapies Center and the Co-Director of the Institute for Surgery and Innovation. He has over 50 publications and has been invited as a faculty/visiting professor at numerous national and international conferences. He is the editor-in-Chief of a textbook on Robotic RadioSurgery and has authored more than 12 textbook chapters. He has received several research grants. One of his recent innovative ideas was awarded the highest ranking from Ohio Third Frontier and received $1 million dollar grant towards its development and is currently submitted to the US Patent office.

    Dr. Ponsky has received numerous accolades for his medical contributions as well as his role and the founder of MedWish International, including U.S. Congressional Recognition, Crains Forty under Forty, as one of Northeast Ohio’s most influential people under the age of 40, Cleveland Upstander: Portraits of Courage, the recipient of the Golden Doc Award, from the Arnold P. Gold Foundation, and received the Rescuer of Humanity Award from Project Love, which recognizes and honors an individual or an organization of national or international stature, which has chosen to use their leadership beyond professional or institutional requirements to positively change the course of humanity. He has also been recognized by the Manhattan Institute in New York with the The Richard Cornuelle Award for Social Entrepreneurship, for originating and effectively implemented a new nonprofit organization providing direct services to those in need. In 2011, he was recognized by Smart Business as the nonprofit board executive of the year and also received the University Hospitals Case Medical Center, Urology Institute Faculty Teaching Award from his students and residents, for recognition of outstanding commitment and efforts to student and resident teaching. Dr. Ponsky also serves as a founding board member of the non-profit MedWorks, which provides free healthcare to the uninsured and underinsured.

    Surgical Video:  Left ureteroscopy, laser lithotripsy, stone basket extraction

    Surgical Video: Left ureteroscopy pyeloscopy stone laser lithotrispsy

    Introduction

    Urolithiasis and its symptomatology were first described in the time of Hippocrates in the 4th century BC. Stone disease has persisted into modern times, and recent data suggests that it is becoming increasingly common. In the United States, the prevalence of stone disease increased steadily throughout the end of the 20th century for both men and women. Overall, prevalence rates for stone disease increased from 3.8% from 1976-1980 to 5.2% from 1988-1994 (1). Similarly, the incidence rate of urolithiasis in the pediatric population also increased 4% per year from 1984-2008 (2). While part of this increase may be due to improved detection of small calculi with higher quality imaging, the rapidly rising prevalence of obesity and diabetes mellitus may also play a role in the increased prevalence of stone disease (3).

    The first ureteroscopy was performed by Young in 1912 when he advanced a cystoscope through an extremely dilated ureter up to the renal pelvis (4). The first flexible ureteroscopy was performed over fifty years later in 1964 when Marshall advanced a flexible scope through an open ureterotomy into the renal pelvis (5). Over the last 20 years, ureterorenoscopy (URS) has revolutionized the management of ureteral, and recently, even renal calculi. Since its initial description, there have been many technological advances in URS including the miniaturization of endoscopes (as narrow as 6 French for flexible and 6.9 French for semirigid ureteroscopes), the enhancement of optical quality through fiberoptic technology, the development of single and compound deflecting mechanisms (with nearly 300 degrees of single deflection), and the creation of digital video ureteroscopes (6). These technical improvements have allowed both semirigid and flexible URS with endoscopic lithotripsy to become first-line minimally invasive stone management strategies.

    Indications

    Treatment options for upper tract urolithiasis depend on a number of factors, including stone location, stone size, stone composition, clinical picture, and patient preference. If obstructing stones are associated with urinary tract infection (UTI) or if non-infected stones are causing high-grade obstruction and cannot be expeditiously treated, prompt relief of the obstruction with placement of either a ureteral stent or nephrostomy tube should precede lithotripsy. In general, stone treatment options include surveillance (trial of spontaneous stone passage with or without medical expulsive therapy), shockwave lithotripsy (SWL), URS with endoscopic lithotripsy and/or stone extraction, percutaneous nephrolithotomy (PCNL), stone dissolution, and open or laparoscopic surgical removal.

    For practical purposes and to avoid unnecessary surgery, surveillance is often attempted first for selected ureteral stones, especially those stones ≤5 mm, given their high rate of spontaneous passage that approaches 70% (7). For patients undergoing surveillance, lithotripsy is indicated for: stones that fail to progress down the ureter, poorly controlled pain, poor gastrointestinal tolerance, worsening obstruction, or renal insufficiency. For ureteral stones of any size, URS and endoscopic lithotripsy with or without stone extraction is a first-line treatment option. URS produces stone-free rates superior to SWL for mid- and distal ureteral stones and equivalent to SWL for proximal ureteral stones (8).

    For renal stones, the applicability of URS depends primarily on stone location and stone size. According to European Association of Urology (EUA) guidelines, URS is an option for stones of all sizes in the renal pelvis and upper or middle calyces and for small stones (<10 mm) in the lower pole (8). For renal pelvis and upper or middle calyceal stones, flexible URS is not recommended as a first-line treatment, especially for stones >15 mm, due to an increased need for staged procedures to achieve similar stone-free rates (8). However, recent evidence suggests that flexible URS may be an alternative to PCNL for renal stones >20 mm (9). For lower pole calculi, PCNL is first-line therapy for stones >15 mm and may even be preferred for smaller stones if negative predictors of SWL success are present. URS appears to offer equivalent efficacy to SWL for small lower pole stones and may be an alternative treatment for larger lower poles stones when PCNL is contraindicated (7,10).

    Furthermore, URS may be a preferred therapy when other approaches are contraindicated, especially due to bleeding diathesis or pregnancy (11,12). This also applies to SWL in the setting of conditions that prevent stone targeting (e.g. morbid obesity or severe skeletal malformations) or nearby arterial aneurysms; and to PCNL in the setting of conditions that increase the risks associated with percutaneous access (e.g. bowel interposition, tumors along the course of the access tract, and renal tumors).

    Contraindications

    Apart from untreated UTI, there are no absolute contraindications to ureteroscopic stone management. In the presence of an active UTI, the high pressures generated from irrigation through the ureteroscope can lead to pyelovenous backflow, seeding the bloodstream with bacteria from the infected urine (13). URS is also contraindicated in the setting of a non-dilated ureteral orifice (UO) that does not easily accommodate the ureteroscope even after dilation, as most ureteral injuries occur when the ureteroscope is manipulated with excessive force (14).

    Special Anatomic Considerations

    Identification and cannulation of the UO prior to URS can be challenging in the setting of an obscured (e.g. enlarged prostate), ectopic, re-implanted, or uretero-enteric UO. Under these circumstances, use of a 70-degree lens or flexible cystoscope with or without the administration of intravenous methylene blue or indigo carmine can aid in identification of the UO. Intubation of the UO may require use of an Albarran’s bridge or flexible cystoscope to achieve the appropriate angle of insertion. Once ureteral access is achieved, the trajectory of the ureter, especially in the setting of re-implanted or uretero-enteric ureters, may restrict the surgeon’s ability to maneuver and deflect the ureteroscope, adding to the difficulty of the procedure (15).

    Obesity is associated with an increased rate of urolithiasis. URS in the obese has been shown to be as effective in achieving stone free status as URS performed in normal weight controls (16). Important technical considerations of which to be aware when planning URS in the morbidly obese or super obese (body mass index >40-50) include: the weight capacity of the operating room table (specifically in dorsal lithotomy), management of the pannus (which may require manual retraction or taping), locating the urethra (which may be buried within the scrotum or deep labial folds), and maintaining urethral access (with guidewires and possibly a long access sheath). It is also important to consider adequate deep vein thrombosis prophylaxis and sufficient padding of all pressure points.

    For symptomatic urolithiasis in pregnancy, greater than 50% of patients may require surgical intervention prior to delivery, and for this indication, URS can be performed safely and effectively (11,17). When considering URS in pregnant patients, the recommended timing of surgery is the second trimester (18). Anesthetic strategies for pregnant patients have been well reviewed (19). In keeping with the principles of ALARA (As Low As Reasonably Achievable) to minimize radiation exposure to the fetus, URS may be performed without fluoroscopy, and stent placement can be confirmed by ultrasound (20).

    Renal calculi in horseshoe and ectopic kidneys are a surgical challenge for SWL and PCNL, but they can be managed effectively with URS. In a study reviewing URS in horseshoe and ectopic kidneys, SFRs were comparable to those achieved for orthotopic kidneys (21). Stone manipulation with basketing and re-positioning may facilitate stone accessibility and fragmentation. Due to abnormal drainage from ectopic renal units, decreased gravel clearance may occur following lithotripsy; therefore, thorough basketing and stone extraction may be beneficial (21).

    Patient positioning / Special instrumentation

    The patient is initially placed in the supine position on the operating room table for the induction of anesthesia. Prior to the introduction of modern small-caliber ureteroscopes and effective short-acting anesthetics, URS was performed exclusively under general anesthesia to minimize patient discomfort associated with lower urinary tract manipulation and the theoretical risk of ureteral injury. In the modern era, many ureteroscopic lithotripsy procedures can be safely accomplished under local and/or intravenous sedation, sedoanalgesia, in appropriately selected patients (22). General anesthesia with neuromuscular paralysis and endotracheal intubation is still the anesthetic of choice for lengthy procedures (greater than 60 to 90 minutes) and for patients with poor pain tolerability (23). General anesthesia may also facilitate renal endoscopy as it minimizes stone movement associated with spontaneous respiration. Spinal anesthesia is often preferred for pregnant patients because it minimizes anesthetic/analgesic exposure to the fetus (24). Following induction of anesthesia the patient is repositioned in the dorsal lithotomy position with the patient’s legs supported in operative stirrups. The patient’s legs are positioned such that the patient’s knees point toward the contralateral shoulder. Care should be taken to ensure that the patient is positioned on the operating room table in such a way as to allow the fluoroscopy c-arm to be placed directly under the patient’s kidneys.

    For all endourologic stone procedures, the standard operating room setup should include a rigid cystoscopy tray, a 5-French open-ended ureteral catheter, and a good working guidewire. When lithotripsy is planned, the lithotripter of choice (e.g. holmium:YAG laser) should be available and ready for use prior to the induction of anesthesia. The ureteroscope(s), semi-rigid or flexible depending on stone location, and a pressurized bag of saline irrigation, or a hand pump mechanism should be available for URS. Semi-rigid ureterosopes are generally restricted to use in the distal and middle ureter due to their limited reach (especially in men) but may be able to access the proximal ureter and renal pelvis in certain circumstances, while flexible ureteroscopes are capable of treating stones throughout the upper tract (albeit with some difficulty in the lower pole). Lastly, a fluoroscopy source is essential. Other materials that may be needed include: a dual lumen ureteral catheter, a variety of guidewires, a ureteral access sheath (UAS), radiographic contrast dye, and various ureteral stents.

    Procedure

    Identification and Cannulation of the Ureteral Orifice

    The procedure begins with gaining access to the UO. A rigid cystoscope with a 30-degree lens is inserted atraumatically via the urethra into the bladder. Pancystoscopy should be performed routinely to exclude other bladder pathology. Following pancystoscopy, the cystoscope is withdrawn to the bladder neck, and the trigone is inspected. The bilateral UOs are identified, and attention is focused on the UO of interest. If a large median prostatic lobe obscures identification of the UOs, a 70-degree lens or flexible cystoscope may be useful. With the UO in view, the cystoscope is rotated approximately 90 degrees in the direction of the affected side. Under minimal bladder filling, the UO is cannulated with a 5-French end-hole ureteral catheter over a floppy-tip guidewire, e.g. Bentson wire (Cook Urological, Spencer, IN) or Sensor wire (Boston Scientific, Natick, MA).

    Retrograde Pyelogram

    After removing the guidewire, half-strength water-soluble radiographic contrast is injected into the ureter via the indwelling ureteral catheter under fluoroscopic guidance, delineating the upper tract anatomy and stone location. In cases of ureteral stones, the retrograde pyelogram should be shot with caution or deferred so as not to propel the stone into the upper collecting system.

    Wire Placement

    The guidewire is again advanced through the ureteral catheter into the ureter under fluoroscopic guidance. If resistance is met, especially at the anticipated level of obstruction, then the ureteral catheter is advanced over the guidewire for additional stability, and advancement of the wire is re-attempted. If this fails, various alternative wires can be substituted, including the 0.035-inch angled-tip and straight-tip Glidewire (Boston Scientific) and the 0.025-inch straight-tip Glidewire. If alternate wires are unsuccessful, wire placement can be performed under direct vision through the working port of a semi-rigid ureteroscope after it has been advanced up the ureter alongside the impeded wire. Rarely, if all attempts at retrograde wire placement fail, the patient may require a staged procedure with percutaneous antegrade ureteral access, followed by stone treatment. The wire is advanced to the level of the kidney until a good curl is noted within the upper collecting system. The ureteral catheter and cystoscope are withdrawn over the wire, while maintaining the wire securely in place. At this point, rigid ureteroscopy can proceed without further manipulation; however, use of a UAS or performance of flexible ureteroscopy requires placement of a secondary (“safety”) wire. For safety wire placement, a dual lumen catheter is advanced over the working guidewire into the UO under direct vision through the cystoscope or using fluoroscopic guidance. Once the UO is cannulated, a secondary guidewire (e.g. Amplatz superstiff or Sensor) is advanced through the other port of the dual lumen catheter into the ureter and kidney until a second curl is noted in the upper collecting system on fluoroscopy. The dual lumen catheter is removed, while maintaining the working and safety wires in place. The safety wire is secured to the surgical drapes with a mosquito clamp to ensure that access to the UO is not lost during the procedure.

    Brand name guidewires differ significantly with regard to flexibility, lubricity and shaft stiffness; therefore, the choice of the appropriate guidewire depends on the clinical application, i.e. obtaining access or coaxial passage of instruments. In general, floppy tip guidewires with a low-friction coating are best suited for obtaining access, while stiffer shaft guidewires are best for the coaxial passage of scopes, catheters, stents, and sheaths (25). Newer hybrid guidewires are designed to have both stiffer shafts and flexible, hydrophilic tips, and this duality makes them useful for a variety of applications (26).

    Semi-Rigid Ureteroscopy

    Semi-rigid URS is ideal for distal and mid-ureteral stones. The semi-rigid ureteroscope is inserted into the urethra and navigated alongside the indwelling guidewire until the UO is encountered.  The ureteroscope is positioned underneath the guidewire, allowing the wire to the tent open the UO. The ureteroscope has a tendency to slip out from underneath the wire during the approach, and several attempts may be required before the UO is accessed. If this is unsuccessful, a superstiff wire can be advanced through the working port of the ureteroscope into the distal ureter. The ureteroscope is oriented between the wires which tents the UO open in opposite directions, like a diamond, allowing the ureteroscope to easily pass through the opening. Once ureteral access is achieved, the secondary wire may be removed. Even after attempting these maneuvers, in certain circumstances, the UO may be too tight to accommodate the semi-rigid ureteroscope. In these cases, balloon dilation, ureteral access sheath placement, or flexible ureteroscopy may be attempted. Alternatively, a ureteral stent can be placed with the intent of treating the stone in 3-7 days after passive dilation has occurred.

    Ureteral Dilation

    Dilation of the UO can be accomplished actively with a ureteral balloon dilator or with 8- to 10-French coaxial dilators, or passively with a ureteral stent. For balloon dilation, a ureteral balloon is advanced over the working wire into the tight UO under fluoroscopic guidance. While the balloon is being filled with contrast under pressure, inflation and ureteral dilation are monitored continuously under fluoroscopy. The balloon catheter must be secured tightly at the level of the meatus, as balloons have a tendency to migrate during inflation. Balloon inflation should be carried out at a set pressure that is dictated by the product specifications of the balloon catheter. We prefer the UroMax Ultra™ (Boston Scientific), which operates best at pressures between 4-17 atm. In a similar fashion, coaxial dilators can be used to serially dilate the UO over the working guidewire, in a similar fashion to dilating a urethral stricture. Ureteral access is then re-attempted as described. Prior to performing ureteral dilation of any type (by balloon, dilator, or UAS), it is critical to confirm that no stones are located at the site of planned dilation based on preoperative imaging and intraoperative retrograde contrast studies to avoid ureteral stone perforation and migration outside the ureter.

    Ureteral Access Sheath Placement

    When treating large or multiple upper tract stones within the proximal ureter and/or upper collecting system by flexible ureteroscopy, requiring longer operative times and repeated entry into the UO, it may be worthwhile to use a UAS. UASs have been shown to prevent harmful elevations in intrapelvic pressures and are purported to improve irrigant flow and visibility; however, their safety is controversial (27,28). For proximal-to-mid-ureteral stones, we prefer to use a 24-cm (short) sheath, which provides sufficient length to reach the distal ureter. For renal pelvis and calyceal stones, we use the 38-cm (medium) sheath with the goal of reaching the ureteropelvic junction (UPJ). Occasionally, in the setting of a long male penile urethra or a morbidly obese patient, a 54-cm (long) sheath may be required to reach the UPJ.

    Prior to insertion, it is important to ensure that the hydrophilic coating on the UAS is wet. The UAS is gently advanced into the ureter over a superstiff wire (alongside a safety wire that is coiled in the kidney) under fluoroscopic guidance. The UAS should not be forced as this can cause ureteral trauma. If buckling occurs, changing the trajectory of the UAS in parallel with the course of the ureter or applying direct perineal pressure on the sheath may facilitate its passage into the UO. The UAS should be positioned just distal to the level of the ureteral stone or at the level of the UPJ for renal stones. The UAS’s internal obturator is removed, and the ureteroscope is advanced through the sheath to the level of the stone or renal pelvis. Lithotripsy proceeds as detailed below. After completion of the procedure, the ureteral access sheath should be removed simultaneously with the ureteroscope, inspecting the ureter for injury upon withdrawal.

    Flexible Ureteroscopy/Pyeloscopy

    Pressurized normal saline is used for irrigation during this portion of the procedure. The flexible ureteroscope is loaded on the superstiff guidewire and advanced up the ureter just proximal to the ureteral stone or to the level of the renal pelvis for renal stones. For radiopaque ureteral stones or renal stones, this can be performed under fluoroscopic guidance. For radiolucent ureteral stones or when using a UAS, this is best accomplished under direct vision. Once the stone is located, lithotripsy is initiated. If a stone is not easily accessible by flexible URS, especially those stones in the lower pole, a stone basket can be used to relocate the stone to the renal pelvis before proceeding with lithotripsy.

    Lithotripsy

    Several endoscopic lithotripters are currently available. We prefer the holmium:yttrium-aluminum-garnet (YAG) laser which produces superior stone fragmentation and minimal tissue penetration. While both the 200-micron and 365-micron laser fibers fit easily through the working channel of the flexible ureteroscope, the larger fiber significantly impairs scope deflection and irrigant flow, relegating its use mostly to the treatment of ureteral and renal pelvis stones with the semi-rigid ureteroscope. Larger fibers do not significantly improve stone fragmentation compared to smaller fibers at a constant power setting (≤1 J), that is, stone fragmentation is dependent on energy density rather than on optical fiber diameter (29). Therefore, the choice of fiber size should be based on the need for scope deflection and the ureteroscope(s) being used (29,30). The ideal energy and frequency settings for small fibers (200-micron and 365-micron) are <1.0 J and 5 to 10 Hz (30). At energies ≥1.0 J, 200-microm fibers are prone to damage and decreased fragmentation efficiency (29).

    Once the calculus is located, the laser fiber is advanced through the ureteroscope and lithotripsy can begin. The laser is initially set at its lowest settings, i.e. 0.6 J and 6 Hz. The settings can be gradually increased as needed. We prefer increasing the power first, followed by the frequency, as high frequencies can impair visibility (30). For ureteral stones, several devices can be deployed to prevent retropulsion of the stone; however, we have found that this can usually be avoided by carefully regulating irrigant flow. Proper stone fragmentation technique involves keeping the laser fiber constantly moving so as to “paint” the outside of the stone, chipping away first at its borders before moving centrally. Breaking the stone immediately into large fragments or creating large craters in the stone by leaving the fiber in one place for extended periods of time should be avoided as these pitfalls hinder efficiency. Fragmentation efficiency is further improved by keeping the laser engaged throughout lithotripsy unless the laser overheats or mucosal injury is imminent. The holmium:YAG laser requires direct contact with the stone for transfer of energy and fragmentation. However, high-frequency non-contact laser fragmentation (the “popcorn effect”) has been shown to significantly decrease stone burden (31). The “popcorn effect” may be most beneficial for stones just out of reach of the ureteroscope (e.g. in the lower pole) or for multiple borderline-sized stone fragments that are slightly too large to pass without further fragmentation. In general, following lithotripsy, stone fragments should be no larger than 2-mm in diameter (approximately 10x the diameter of the 200-micron laser fiber). Larger fragments can be carefully retrieved under direct vision using a stone basket. Smaller stone fragments are allowed to pass spontaneously.

    Following stone fragmentation, the upper collecting system and/or ureter are/is inspected again to ensure adequate stone clearance and to detect any previously unrecognized injuries prior to completing the procedure. For flexible URS, pyeloscopy is performed. With the safety wire still in place, the ureteroscope is then slowly withdrawn from the kidney and/or ureter inspecting the entire ureteral lumen on removal. If a UAS is used, the ureteroscope is withdrawn simultaneously with the sheath.

    Ureteral stent placement

    Ureteral stent placement is considered optional after ureteroscopic lithotripsy. The decision to leave a stent is surgeon-dependent and should probably be based on the degree of ureteral injury and/or inflammation.

    The safety wire is detached from the surgical drapes, and the rigid cystoscope is back-loaded on the wire. The cystoscope is then re-inserted into the bladder, and the ureteral stent is advanced over the wire into the renal pelvis. The wire is removed, and placement is confirmed by noting a good curl in the kidney and the bladder on fluoroscopy and cystoscopy, respectively. Alternatively, stent placement can be performed entirely under fluoroscopic guidance. The patient’s bladder is emptied, and the cystoscope is removed.

    Complications

    Complications of flexible and semi-rigid URS can be divided into three distinct groups: intra-operative, early, and late complications.

    Intra-operative complications tend to be associated with damage to the ureter during advancement of the ureteroscope or forceful manipulation of stones within the ureter. A recent study of semi-rigid URS found the most common intra-operative complications (2.6%) include ureteral avulsion (0.1%) and ureteral perforation (1.7%) (32). Complete ureteral avulsion is a devastating complication, diagnosed when the avulsed ureter is seen protruding from the urethra in the female or emanating from the UO in the male following aggressive stone basketing, that generally requires open repair. Rates of ureteral perforation are lower using contemporary small-caliber ureteroscopes (0%-4.7%) compared to larger caliber ureteroscopes, and as a result, perforation rates have decreased dramatically over time (33). Ureteral perforation can generally be managed with ureteral stent placement for 3-6 weeks with open repair rarely being required. Ureteral intussusception is a rare complication that has been reported with both retrograde and antegrade manipulation of the ureteroscope and/or ureteroscopic instruments that also requires open repair of the injured ureteral segment. Other minor intra-operative complications of flexible and semi-rigid URS include creation of false passages (0.4%-0.9%), usually from guidewire manipulation, mucosal abrasion (6%-24%), thermal injury from lithotripsy equipment (0.2%-1%), and extravasation (0.5-2.3%) (33). Of note, extravasation of ureteral stone fragments into the retroperitoneum has been reported and can generally be managed with ureteral stenting. (33)

    Early complications (6.0%) include sepsis (1.1%), persistent hematuria (2.0%), and renal colic (2.2%) (32). Steinstrasse is another early complication that can occur following treatment of large stone burdens (33).

    Late complications are relatively rare (0.2%), and the predominant manifestation is ureteral stricture (0.1%) (32). Ureteral stricture rates as high as 16.2% have been reported in historical series. However, as with intra-operative complications, lower rates of early and late complications occur with small-caliber ureteroscopes. Ureteral strictures are associated with intra-operative complications such as ureteral perforation and lithotripsy of impacted stones. (33)

    Outcomes Data

    The most important outcome of ureteroscopic stone procedures is the rate at which stone-free status is achieved. Unfortunately, a standardized definition of determining and reporting stone free rates (SFR) does not exist in the literature. Despite this limitation, numerous studies have been published in recent years comparing SFRs between URS, PCNL, and SWL. Results of selected studies are displayed in Tables 1. We have attempted to report, when possible, the SFR after one treatment session.

    For further study, a comprehensive review of outcomes (SFRs) after primary treatment with SWL and URS in the general population can be found on page 59 of the 2011 update of the EUA’s Guidelines on Urolithiasis (8).

     

    outcomes of ureteroscopy laser lithotripsy (urologybook)

    Stone free rates following URS, PCNL, and SWL.

    Final Thoughts/Surgical Pearls

    • A safety wire should always be used when performing URS to ensure that access to the ureteral orifice and kidney is not lost during the procedure.
    • The holmium:YAG laser fiber must be in direct contact with the calculus in order to transmit its energy for efficient fragmentation.
    • Stone basketing should always be performed under direct vision. It should only be used for fragments small enough to pass easily through the ureter or UAS without causing additional trauma.

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