Ureteroscopy: Endoscopic Examination of the Upper Urinary Tract
Indications for Ureteroscopy
- Abnormal imaging findings (obstruction, ureteral strictures, filling defects)
- Diagnosis of hematuria</li>
- Diagnosis of pathologic urine cytology
- Diagnosis and treatment of ureteral stones and kidney stones
- Diagnosis or treatment of strictures or tumors of the ureter or renal pelvis
Contraindications to Ureteroscopy
Urinary tract infection
, urosepsis, uncorrected bleeding diasthesis. Contraindications for lithotomy position
Endoscopic Instruments for Ureteroscopy
Rigid ureteroscopes look like a long thin cystoscope, they have usually non-interchangeable lenses with 0–10 degrees angle of view. The working channel is 5 CH wide, there is a connection for inflow and outflow of irrigation. The thickness of a rigid ureteroscope is between 6–9 CH, thin at the tip with a gradual increase in diameter. Technical refinements have enabled semiregide ureteroscopes with 5–7 CH in diameter.
Flexible ureteroscopes are 8–10 CH in diameter, the working channel is thinner (CH 3) than in rigid ureteroscopes. Modern flexible ureteroscopes have a additional channel for irrigation. The tip of the flexible ureteroscope can be actively controlled with deflection up to 270 degrees [fig flexible ureteroscopy].
Flexible ureteroscopy: every renal calix can be examined..
Technique of Ureteroscopy
Patient Preparation before Ureteroscopy
Cystoscopy and Retrograde Pyelography
After cystoscopy a retrograde pyelography is done to evaluate the anatomy of the upper urinary tract and to review the indications for ureteroscopy. With help of a ureteral catheter, a guide wire is inserted up to the renal pelvis [fig. diagram of retrograde pyelography].
Left side: urinary tract (right side) with a distal ureteral stone.
Middle: after inserting the ureteral catheter, contrast medium is injected.
Right side: a guide wire is inserted into the upper urinary tract via the ureteral catheter.
A narrow ostium makes the dilation of the prevesical ureter necessary [fig. dilatation of the distal ureter (left picture)]. Alternatively, the urinary tract can be dilated with the insertion of a DJ stents. The ureteroscopy is postponed for 2–4 weeks.
The ureteroscope is advanced along the urethra and guide wire, until the ostium is in sight. If the intubation of the orifice is technically difficult, a second guide wire or thin ureteral catheter may help [fig. entry of the distal ureter with the ureteroscope].
Entry of the distal ureter with the ureteroscope in difficult cases:
Left side: dilatation of the orifice with ureteral bougies (9–11 CH).
Middle: insertion of the ureteroscope. Before the ostium, the ureteroscope is rotated for 180 degrees, this avoids the stucking of the oblique ureteroscope with the cranial lip of the ostium.
Right side: the ureteroscope is advanced along the guide wire into the ureter.
The ureteroscope is advanced along the guide wire under direct vision into the ureter. The irrigation should be adjusted as low as possible. Kinking of the ureter can be straightened with the help of guide wires and ureteral catheters [fig. straightening a ureteral kinking during ureteroscopy].
Straightening of a ureteral kinking: the ureteral kinking (left) is straightened with the help of a ureteral catheter and allows the ureteroscopy into the renal pelvis (right). With kind permission of Dr. R. Gumpinger, Kempten.
After inserting the guide wire, an access sheat is inserted into the proximal ureter for easy entry of the flexible ureteroscope into the ureter, especially when a large stone burden is encountered. After advancing the flexible ureteroscope into the renal pelvis, every renal calix is inspected [fig. flexible ureteroscopy].
Ureteroscopic Treatment of Urolithiasis
Extraction of ureteral stones with grasping forceps:
Small ureteral stones can be easily extracted with grasping forceps. Forceps for ureteroscopy are mostly reusable, their application is cheap.
Extraction of ureteral stones with dormia baskets:
Ureteral stones, which are small enough to be extracted completely, can easily be removed with Dormia baskets [fig. extraction of ureteral stone with Dormia basket]. Major disadvantage of Dormia baskets are the costs of the disposable instrument.
First, the closed Dormia basket is advanced between stone and ureter wall. Beware of fixed ureteral stones, as the fragile ureteral wall can easily be perforated. Above the stone, the Dormia basket is opened and pulled back. With manipulation (e.g. rotating), the Dormia basket is manipulated around the ureteral stone. The Dormia basket is slowly closed untill the stone is trapped within the basket. The ureteroscope is slowly withdrawn together with the Dormia basket, which should be controlled with direct vision. The ureteral stone should glide along the urothelium. The extraction should be stopped, if the stone gets impacted and the resistance for the extraction rises, to minimize the risk for ureteral avulsion. After opening of the Dormia basket, the stone should be disintegrated.
||Ureteroscopy: extraction of a ureteral stone with a Dormia basket
Top left: ureteroscopic view of a ureteral stone.
Top right: Passage of the closed Dormiaschlinge between stone and ureteral wall.
Middle left: the opened Dormia basket is manipulated around the stone.
Middle right: closing of the Dormia basket.
Bottom left: Passage of the ureteral stone through the distal narrow ureter.
Bottom right:ureteroscopic view of the ostium with a small lesion after extraction of the stone
Lithotripsy of ureteral stones:
Larger ureteral stones cannot be extracted in toto, they need a lithotripsy in the ureter. Afterwards, the fragments can be removed.
The following possibilities for ureteroscopic lithotripsy exist:
- Electromechanical lithotripsy (e.g. Lithoclast)
- Electrohydraulic lithotripsy (EHL)
- Holmium laser lithotripsy
Laser lithotripsy has the advantage of minimizing the trauma to the ureter and to reduce the stone dislocation during lithotripsy [fig. Holmium-Laser lithotripsy]. Furthermore, 3 CH-probes for flexible ureteroscopy are available.
Lithotripsy with Holmium-Laser
Ureteroscopic Treatment Options for Strictures and Tumors
Biopsies should be taken from tumors or strictures of unknown etiology. For rigid or flexible ureteroscopes, there exist a varitey of biopsy forceps. The amount of resulting tissue with ureteroscopic biopsy is very small. Multiple biopsies are necessary, to obtain a reliable diagnosis.
Ablation of ureteral tumors:
Endoscopic palliative treatment of ureter or renal pelvis tumors is possible with ureteroscopic resectoscopes. Alternatively, tumor ablation is possible using laser coagulation.
Ureteroscopic incision of ureteral strictures:
see section ureteral strictures.
Stenting of the Ureter
After ureteroscopy, especially after longer manipulation, the placement of a DJ ureteral stent is necessary for 2–4 weeks. If a perforation of the ureter happens, a bladder catheter (for a few days) and an DJ ureteral stent should be placed, to allow a pressure-free urine drainage. In several randomized studies, the placement of a DJ have been dispensed with success after uncomplicated ureteroscopy with ureteral stone extraction.
Complications of Ureteroscopy
Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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