ENDOSCOPY OF UPPER URETER
SUBODH KUMAR DAS*, ANANT KUMAR**
*Senior Resident; **Additional Professor, Department of Urology and Renal Transplantation, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
The trend in medicine has been shifting more towards non-operative or minimally invasive surgical procedures in the last few decades. This has been apparent in almost all the fields of medicine. Often minimally invasive endoscopic procedures replace open surgical procedures. As part of this increasing trend toward non-operative therapy, there has been a steady increase in the number of endoscopic procedures performed in the upper urinary tract, including transurethral ureteroscopy, percutaneous nephroscopy, and antegrade ureteroscopy. Ureteroscopy is an extension of cystoscopic techniques in the bladder and involves similar indications. The main differences relate to the anatomy of the ureter and kidney compared with the lower tract, the smaller size of the instruments and the narrower margin of safety for the prevention of complications.
Anatomy of the Ureter
Ureter is a narrow muscular cylindrical tube lying in the retroperitoneal space, extends from the UPJ above to the ureteral orifice below. In adults its length varies from 24 to 30 cm. It performs the task of transporting urine from the kidney to the bladder. Under physiologic conditions, its lumen is approximately 3 mm wide, and the endothelial lining in a non-distended ureter is folded six times. With distension, these folds efface, and therefore, are not seen at ureteroscopy. The ureter is constricted at its origin from the UPJ, at the level of pelvic brim where it is crossed by the iliac vessels, and at the ureterovesical junction where its lumen is narrowest. The upper ureter extends from the UPJ to the level of the pelvic brim. It lies posterior to the peritoneum over the psoas major muscle, which separates it from the tips of transverse processes of the lumbar vertebrae. Gonadal vessels, usually at the level of the fourth lumbar vertebra, cross the upper ureter. It enters the pelvis by crossing anteriorly from the medial side to the lateral side at the termination of the common iliac vessels or the beginning of external iliac vessels. During endoscopy the upper ureter is seen as a relatively straight lumen.
On the right side the ureter is related craniocaudially to the second part of the duodenum, right colic and ileocolic vessels, mesentery, and the terminal portion of the ileum. On the left side, the ureter is crossed by the left colic vessel and then passes posteriorly to the sigmoid colon and its mesentery.
The most important aspect of endourologic management of the ureter and the intrarenal collecting system is the availability of an appropriate array of instruments. In addition, all of the procedures to be discussed are best performed with C arm fluoroscopic control and a dedicated fluoroscopic table.
A wide variety of ureteroscopes are available for diagnostic and interventional uses. Their discussion can be divided into the categories of rigid and flexible instruments.
Flexible ureteral endoscopes have become a readily available urologic instrument. The standard flexible ureteroscope is now an actively deflectable ureteroscope of approximately 7.5-8F. This endoscope has an actively deflectable segment which can be deflected by a moving thumb liver on the handle. The tip deflects 170 to 180 degrees in one direction and 90o or more degrees in the opposite direction in the same plane. There is also a secondary or passively deflecting segment, which is a segment in the shaft which is relatively more flexible than the other portions of the shaft. When the actively deflected ureteroscope is advanced against the upper margin of the pelvis, the instrument bends again at the secondary deflecting segment. As the actively deflected portion is straightened, it can extend in the lower infundibulum. This secondary deflecting segment has been useful to reach the lower infundibulum in 60% of patients studied.
An irrigation/working channel is essential for passing instruments and irrigating fluid, and is essential for useful visualization within the urinary tract. The channel is 3.6F in most ureteroscopes.
This flexible ureteroscope can be passed easily into the ureter with minimal, if any, dilation, can accept most useful working instruments and still has adequate irrigation capacity. The optimal range for the flexible ureteroscope is the mid and proximal ureter and itrarenal collecting system.
Rigid Endoscopes with Fibre Optic Imaging Bundles
The other major group of ureteroscopes includes the small diameter rigid endoscopes utilizing fibreoptic-imaging bundles. These have also been called semi rigid endoscopes.
One of the major benefits of this design is the ability to incorporate a relatively larger lumen within the smaller outer diameter of the endoscope. It is usually possible to pass these smaller endoscopes into the ureter without prior dilation. The ureteroscope can also be bent or angled without losing any portion of the visual field. This feature can also be a disadvantage since the endoscope can be angled to the point of breakage without any warning for the loss of visualization. Other disadvantages, include the fibre optic image and the need for focusing. However, these endoscopes can be made as small as 6 to 7 F with one or more working channels. The optimal range of these ureteroscopes within the ureter is in the distal portion.
Most working instruments are now available in sizes 3F or less. These instruments can fit through the working channel of the flexible ureteroscopes and small diameter rigid endoscopes. Available instruments now include wire pronged graspers, snares, baskets fulgurating electrodes, electrohydraulic lithotriptor probes, laser fibres and biopsy brush. When placed into the channel within the flexible ureteroscope, these instruments limit the deflection of the tip.
Several new retrieval baskets have been introduced. Different designs and materials have different purposes and advantages. As an example, if the helical and the flat wire baskets can be compared. The helical basket can be rotated to engage a stone impacted within the ureter. The flat wire basket without a tip has been introduced with wires made of nitinol. This material will not kink or deform during use. Other baskets have increased the radical strength of opening by using wires with shaped cross section in the form of triangle or D rather than the usual flat or round wires. These instruments can be used for specific applications to optimize stone retrieval.
The sheathing material used on retrieval devices is one of the most overlooked aspects of these devices. Generally, Teflon or polyamide is employed. These material vary in their size, stiffness, friction and durability (Table 1).
Actively deflectable flexible ureteroscopes
Company Outer size (F) Channel Deflection Circon – ACMI 9.8 3.6 160° 8.5 2.5 160° 7.4 3.6 120 + 160° Olympus 9.9 3.6 100 + 180° 8.4 3.6 180 + 180° Storz 7.5/8.2 3.6 120 + 170° Wolf 9.0 3.3 90 + 180° 7.5 3.6 130 + 170°
Indications for ureteroscopy of upper ureter
Evaluation of radiographic filling defects or obstruction
Evaluation of unilateral gross haematuria
Evaluation of unilateral malignant cytology
Surveillance after conservative treatment of an upper urinary
Therapeutic procedures for non calculous disease
Passage of ureteral catheter for obstruction or fistula
Removal of a foreign body
Resection/fulguration of selected tumours
Dilation/incision of strictures
Upper ureteral calculi, after failed ESWL
Renal calculi, after failed ESWL
Post ESWL steinstrasse
Calculi associated with obstruction
Calculi plus suspicion of urothelial malignancy
Ease of introduction
Use of larger/rigid working instruments
Limited use above iliac vessels
Cannot visualize entire intrarenal collecting system
Improved mobility above iliac vessels
Can reach entire intrarenal collection system
Accommodated natural tortuosity of ureter
Moves with the patient
Less useful in the distal ureter
Difficult to reinsert into the ureteral orifice
Must be passed over a guide wire
TECHNIQUE OF URETEROSCOPE INSERTION
The performance of ureteroscopy requires a sound knowledge of the endoscopic anatomy, the instruments, and a methodical approach. With the appropriate instruments and the proper technique, both rigid and flexible ureteroscopy can be performed confidently with safe and successful results.
A thorough history and physical examination are essential before ureteroscopy to identify any premorbid factors that might complicate the procedure. The presence of obstructive voiding symptoms in an older man suggestive of prostatic enlargement might make access to the ureteral orifice difficult. A previous history of ureteral reimplantation, open uteteral surgery, or pelvic irradiation might preclude a successful outcome with ureteroscopy. In patients with musculoskeletal deformities of the bony pelvis and hips, proper positioning for ureteroscopy may be impossible.
A review of the ureteral anatomy is an integral part in the preparation of each uterteroscopy case. A recent intravenous pyelogram or retrograde pyelogram should be studied to identify any pathologic process, the course of the ureter, the presence of ureteral tortuosity, or areas of narrowing.
Before ureteroscopy, any urinary tract infection must be treated with an adequate course of antibiotics. In addition, a single intravenous dose of an aminoglycoside or broad-spectrum cephalosporin is given preoperatively.
A modified cystolithotomy position is employed in most cases. The ipsilateral thigh is placed almost parallel to the lower abdominal wall, resulting a displacement of the distal ureter anteriorly. The patient’s contralateral hip should be hyperabducted to allow the surgeon access under the elevated led to approach the orifice at the necessary angle.
Cystourethroscopy is performed and a guidewire is passed into the ureter. A 0.038" floppy tip, Teflon coated Bentson guide wire is suitable in most cases. Under fluoroscopic guidance the wire should be advanced until it is seen to curl within the renal pelvis. The most important use of the guide wire is that it allows access to the collecting system for ureteral catheter or stent placement in the event of any ureteral injury.
The ureterovesical junction is the narrowest segment of the entire ureter, with an average diameter of 3 to 4 mm. Dilation of the ureteral orifice and intramural ureter is necessary to allow the passage of 9 to 12F or larger endoscopes. Various graduated Teflon dilators and metal bougies have been used. These devices however are limited by the need for multiple passages and may cause considerable urothelial trauma. One of the more innovative devices for dilation is the Ureteromat. This device uses a hydraulic pump to produce a continuous jet of fluid irrigation, creating pressures of up to 200 mm Hg and flow rates of 400 ml/min. With this system, the ureteral orifice is opened in an atraumtiac fashion to allow ureteroscope insertion.
The indications for diagnostic ureteroscopy include radiographic filling defects or obstruction, tumour found cystoscopically near or at the ureteral orifice, unilateral upper tract haematuria, and upper tract urinary cytology suggestive of malignant cells.
In unilateral upper tract haematuria, inspection must be carried out carefully in a stepwise fashion to avoid disturbing the appearance of a lesion before viewing it. The first step is catheterization of the ureteral orifice with ureteral urine sampling for cytology. A retrograde pyelogram is performed with dilute contrast to define the renal collecting system and ureter. Ureteroscopy of the distal ureter is then performed with a rigid mini ureteroscope. The reminder of the ureter is then inspected with flexible ureteroscope after placement of a guide wire into the distal ureter. This guide wire is advanced under direct vision at the tip of the flexible ureteroscope, thus allowing inspection of undisturbed mucosa.
Lesions found during ureteroscopy for essential haeamaturia include hemangiomas and arteriovenous malformations. Small lesions can be fulgurated ureteroscopically when visualized. Occasionally tumours may be visualized.
With the development of rigid and flexible ureteroscopes, ureteroscopy has been used increasingly in establishing the diagnosis of upper tract urothelial tumours. The diagnostic accuracy upto 90% for the ureteral tumours has been reported in the literature. The major concerns about performing ureteroscopy in patients with upper tract TCC include a risk of ureteral perforation with extravasation of tumour cells, denudation of the ureteral mucosa facilitating tumour implantation, complete ureteral disruption or stricture formation and pyelovenous lymphatic migration of the transitional carcinoma cells. Because of the potential complications and a risk of understaging and undergrading of the tumour, diagnostic ureteroscopy which is an invasive procedure requiring full anaesthesia should be reversed for patients in whom the diagnosis remains in doubt after using conventional diagnostic techniques and for those in whom the treatment would be influenced by the results of ureteroscopy.
Passage of an ureteral catheter
Ureteroscopy has been found to be effective in managing ureterocutaneous fistula, enabling passage of a catheter or stents beyond the fistula site. In these instances employing either the No 9.5 Fr instrument with a No. 5Fr accessory channel or the smaller No. 8.5F instrument with a No. 3.5Fr channel has been most satisfactory. These instruments are especially valuable in instances in which dilation of the orifice and tunnel is made impossible by prior trauma. They often may be inserted directly into the orifice without prior dilation.
Retrieval of Foreign Bodies
Another indication for ureteroscopy is the retrieval of ureteral stents that have migrated or of broken instrument parts, such as portions of stone baskets that are retained in the ureter. This is not a common indication, and often this method of retrieval is difficult because of associated ureteral oedema and inflammation. The three - prong grasping forceps, alligator forceps, or stone basket should be used for these retrievals.
Incision and dilation of ureteral strictures
Postoperative ureteral strictures have been treated by ureteroscopic methods. The procedure involves incising the region of narrowing under direct vision using rigid or flexible ureteroscope. The incision is made with either a cold knife ureterotome or a cutting electrode. The area may then be dilated with a 5 or 6 mm balloon dilating catheter to complete the treatment. Incising the stricture ensures controlled splitting of the ureter during the dilation process. An internal ureteral stent, a nephrostomy tube or both are left in place for 4 to 6 weeks after the procedure. The long-term success of this technique remains to be seen, but the preliminary results are encouraging, and it offers definite advantage over repeat open surgery.
URETEROSCOPIC BIOPSY, RESECTION AND FULGURATION
The diagnosis of upper urinary tract tumours can pose significant challenges to the urologist. Voided urinary cytology is usually inadequate and non-specific for detection upper tract abnormalities. Previous studies documented only 33% to 45% positive yield. low-grade tumours are expected to exfoliate normal or minimally atypical urothelial cells, resulting in negative cytologic reports. Retrograde brush biopsy has been shown to yield a definitive diagnosis much more frequently than voided urine or ureteral catheterization. Ureteroscopy can be used to directly access a filling defect for inspection or sampling. Combined use of small diameter rigid ureteroscopes and actively deflectable flexible ureteroscopes permit examination of the whole collecting system. Ureteroscopic biopsy of upper tract lesions allows for histological examination of tissue samples and improves diagnostic accuracy over that of brushing techniques.
Because ureteroscopically obtained samples are small, techniques for handling and processing samples are crucial. Biopsy of suspicious lesions inside the ureter requires the forceps to the applied parallel to the ureteral mucosa. Biopsy is performed during the first pass of the ureteroscope. The lesion may get traumatized or inadvertently avulsed during the initial passage if any attempt is made to examine the entire upper tract and then biopsy. When the lesion is identified, the No.3 or 5F cup forceps is carefully advanced with its jaws parallel to the ureter wall. The intraluminal portion of the lesion is then grasped with the jaws and pulled free from the ureter using gentle traction on the forceps. A potential problem is losing the biopsy specimen as it is pulled through the instrument sheath. To avoid this problem, either the telescope is removed first, thus providing more room within the sheath or the entire scope is removed including the forceps.
While doing ureteroscopic resection, the basic transurethral resection electrosurgical principles should be maintained; using an irrigant such as glycine or water and using the appropriate setting on the coagulation and cutting currents to provide the most effective surgery with the least tissue injury.
The actual technique of resection of an upper tract are different than the bladder or prostate. Only intraluminal tumour is resected, and no attempt is made to take deep arcing bites into the ureteral wall. For this reason, the tip of the resectoscope is positioned directly distal to the tumour. The loop is extended beyond the tumour, and before activating the power, the tissue is drawn back toward the tip insulation or directly outside, the power is started and the tissue is resected. This method helps to ensure cutting of only the desired tissue and prevents injury to the surrounding ureteral wall. After resection of all intraluminal tumours, the base of the lesion is lightly fulgurated with resectoscope loop. Smooth to and fro movements are used to cauterize the region of the resected tumour. Fulguration is also possible with Bugbee or bipolar electrode. The probe is advanced through the sheath and gently positioned on the area to be fulgurated. With irrigation flowing, the coagulation current is activated. Irrigation is necessary to maintain clear visualization and to dissipate bubbles that are produced.
Ureteroscopy for upper ureteric stones
Retrograde ureteroscopy was initially used for the distal ureteral calculi. The development of smaller caliber rigid ureteroscopes, flexible ureteroscopes, and improved flexible contact lithotriptors has allowed for its application to the more proximal portions of the ureter. However the length of the ureter and the tortuous course that must be traversed make retrograde ureteroscopic treatment of ureteral calculi technically challenging. Although some investigators reported stone free rates for ureteroscopic treatment of proximal calculi in excess of 80%, some of these studies include stones pushed back up to the kidney and treated with ESWL among their success. Other studies examining primary ureteroscopic management of proximal calculi reported success rates ranging from 38 to 50%.6 Prior endoscopic manipulation also has not shown to improve the efficacy of ESWL in upper ureteric stones. In addition the incidence of complication such as ureteral stricture, perforation, and avulsion is significantly increased in the proximal ureter. Therefore, ureteroscopic treatment of proximal ureteral calculi is best reserved for patients who are unsuitable for ESWL or as a salvage procedure in patients who fail ESWL.
Ureteroscopic management of upper ureteric tumours
Upper ureter is the least common site accounting for 3% of all ureteral transitional cell carcinomas. Advocates of endoscopic resection for low grade, low stage ureteral tumours report results similar to those seen in conservative surgery. Overall, the ureteral tumours appear to respond somewhat better than pelvic tumours to endosurgical management. Both the recurrence rate in TCC of the ureter cases at approximately 2 years (15%) and the progression to open ablative surgery (13%) is low.
Rationale for endoscopic Treatment of UTT Ca
Extension of well-accepted endoscopic treatment of bladder TCCa
Generally good results of other nephron sparing treatments
Development of smaller instruments
Indications for conservative therapy
Limited renal function
Compromised contralateral kidney
Severe medical disease
Low grade, low stage distal ureteral tumours
Diagnosis of UTTCCa
Filling defect on contrast study
Exclude radiolucent stone
Biopsy (3F cup, Segura basket)
ND YAG laser
Holmium YAG laser
Requires large (12F) ureteroresectoscope
Must dilate ureter
Useful only in distal ureter
Good for large distal tumours
2 to 3 Fr electrocautery probes
Can be used with flexible ureteroscope
Good for smaller tumours
Nd YAG laser
Tissue absorption 4 to 6 mm
Flexible, small diameter quartz fibres
Can be used with flexible scope
Do not touch tissue with tip of fibre
Coagulated tissue may need to be removed
Tissue absorption 0.4 mm
High power ablative effect
Flexible, low water content fibres
Can be used with the flexible ureteroscope
Tip must be in contact with the tissue
Percutaneous Interventions for upper ureteric lesions
The developments of methods of percutaneous access to the renal collecting system and the availability of ureterorenoscopes and nephroscopes of superior optical quality have made endoscopic evaluation of upper ureter a reliable and practical technique. The application of percutaneous approach in upper ureteric lesion has diagnostic and therapeutic ramifications. The diagnostic aspects include the delineation of disease by the antegrade injection of contrast and direct examination of the intrarenal anatomy and upper ureter when a standard intravenous urogram or retrograde examination has failed to provide an adequate diagnosis. The therapeutic applications include treatment of upper ureteric stones and strictures.
Percutaneous management of upper ureteric strictures
To discus the percutaneous management, these strictures can be divided technically into three groups- (1) Those through which a guide wire can be passed, (2) Those through which a guide wire will not pass but that do retain patency with the midureter or lower ureter, and (3) Totally obliterated upper ureter. Different therapies are required to correct these conditions.
Strictures through which a guide wire may be passed
These represent the simplest types of strictures. The optimal access is obtained through middle or upper pole calyx. After access has been obtained into the renal pelvis, a guide wire is passed down the ureter, often aided by a cobra catheter, under direct nephroscopic vision or fluoroscopc guidance. When the wire is in place, the incision is made along the posterolateral surface of the ureter through the full thickness of the stricture until retroperitoneal fat is seen. The incision should be extended for approximately 1 cm beyond the stricture. Following the incision, a 14 F nephrostent, 7 or 8 F double J ureteral stent, or 14/7 F endopyelotomy stent may be placed. A Foley’s catheter should be placed in the bladder for 24 to 36 hours to prevent urinary reflux through the stent. Stenting should be maintained for 4 to 6 weeks.
Strictures through which a guide wire will not pass but that retain patency
If the stricture is too tight for a guide wire to pass, placement of a 5 or 6 Fr open ended ureteral catheter to the point of obstruction is crucial. Contrast material, methylene blue, or both can be injected in retrograde fashion, and if the renal pelvis can be visualized or if methylene blue is seen coming through the stenotic area, one can attempt to pass guide wire retrograde through the ureteral catheter. If the wire comes through, it is curled into the renal pelvis, and the operator then proceeds with the incision. If the wire is not seen the operator may carefully cut down on the stricture until the wire appears. When the wire is visible, it can be grasped and pulled through, so that continuity is established. Finally cutting and dilation can then proceed as previously described.
Totally obliterated ureter
In severe ureteral strictures, when there is total obliteration a very fine wire protected by an insulating catheter is passed through flexible nephroscope. Under careful visual and fluoroscopic control, this wire can be guided through the stricture into the lower part of ureter with a cutting current. Once it has entered the ureter, protecting catheter can be passed over the wire, bypassing the stricture. This wire is then replaced with a routine 0.038" guide wire. Once communication has been reestablished with the wire, cutting, dilation, or both is completed. Finally, an appropriate stent should be placed over the guide wire. This method is a good alternative to open surgery for < 1 cm strictures. However, longer strictures, which are more common, are better treated by open surgical procedures.
Percutaneous Management of Upper Ureteric Stones
Contemporary clinical experience strongly supports in situ ESWL as the initial treatment for the majority of upper ureteral calculi, even those that appear totally obstructing. The only exceptions include large (greater than 1.5 cm) ureteral calculi or urosepsis necessitating stent bypass or nephrostomy tube placement to preserve renal function or to drain an infected kidney.
Ureteroscopy is presently considered a first line salvage therapy procedure for upper ureteral calculi that have failed ESWL. With the advent of flexible ureteroscopes and ancillary equipments like laser and electrohydraulic probes, the stone free rate achieved by ureteroscopy for upper ureteric stones has been reported to be as high as 80 to 95%. Upper ureteral calculi that fail ESWL and retrograde ureteroscopic manipulation may be the candidates for a percutaneous antegrade procedure. PCNL is often performed in these dilated systems and is highly effective, although invasive. The stone free rate using this approaches 88 to 100%. Although the percutaneous nephrostomy approach for upper ureteral calculi has a high success rate, the associated post operative morbidity, the significant operative and post operative complication rates, and the long convalescence time make it only a salvage procedure for patients who have failed ESWL and ureteroscopic manipulation.
There is smaller margin of safety for endoscopic surgery in the ureter and kidney mainly because of the smaller anatomic size of the ureter as compared with the urethra. As instrumentation is improved, with the addition of small caliber rigid endoscopes, dependable flexible uretero scope, and newer methods of intraureteral lthotripsy, this safety margin should widen. Operator error, however whether in judgement or in technique, can still lead to disastrous complication; therefore, it is necessary for the urologist to be familiar with the types of injuries that may occur, the appropriate means for diagnosing these injuries, and their treatment.
Anatomic constraints that may prevent successful ureteroscopy
Significant prostate enlargement (especially median lobe)
Severe hip or pelvic deformity
While defining the causes of the iatrogenic injuries, it is important to consider the anatomy of the upper urinary tract. The proximal ureter has a much lesser muscular support than the intramural ureter and the supravesical ureter. Also, the number of mucosal cell layers is substantially greater in the lower ureter[3-5] than it is in the upper ureter.[1-2] Thus the likelihood of a complete perforation is much more in the proximal ureter in comparison to the distal ureter.
Endoscopic manipulations may add to the incidence of devascularization and necrosis resulting in stricture formation. Other causes of stricture formation after ureteroscopy include mucosal tears, extravasation, and thermal injury secondary to intraureteral lithotripsy. Electrohydraulic lithotripsy causes the greatest temperature increase, and use of this device has been associated with the greatest incidence of ureteral injury.
Most ureteral injuries can be managed conservatively. The obvious exception to this is avulsion of the ureter. Avulsion of the upper ureter may require substitution with a bowel segment, autotransplantation or nephrectomy.
Conservative management generally suffices for other injuries. Once a false passage or perforation is recognized, stenting of the ureter with an internal stent or ureteral catheter most likely allows complete resolution of the injury. If stenting is not possible, a percutaneous nephrostomy should be inserted to provide urinary diversion. The stent or the nephrostomy tube should be kept for 6 weeks. Before removing, a contrast study is done to document complete healing. Ureteral stricture may be managed conservatively, with balloon dilation. In some instances, open exploration and repair are required.
Prevention of ureteroscopic injuries
Careful patient selection
Complete urologic work up
Availability of essential instruments
Availability of fluoroscopy
Sound urologic judgment
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