URETEROSCOPY - LESSONS LEARNT
Consultant Urologist, Excel Urology Centre and Shushrusha Hospital.
It’s an old saying that only fools rush in where angels fear to go. Urologists being the fools that they are did venture into Ureteroscopy and in fact over the last decade they have done very well this procedure.
In the first five years (1988-1993) colleagues from other medical faculties indeed feared Urologists performing Ureteroscopy. However, with rapid miniaturization of the instrument and the economical fragmentation devices available now, have popularized the procedure and minimized the incidence of failure as well as complications.
The average diameter of the ureter varies between 3 and 5 mm and therefore most of the surgeons in allied faculties are indeed surprised when they hear about Ureteroscope entering the ureter. There are four sites of natural constrictions:
The ureteric orifice
The intramural portion of the ureter.
The level of crossing of iliac artery and
The uretero pelvic junction.
Endoscopically the ureteric orifice itself could vary from pinpoint to a large gaping opening. The lower ureter appears star shaped while the upper ureter appears circular. There are multiple folds which one might encounter in its course. The upper calyx and the middle calyx can be identified easily with the rigid ureteroscope and even the infundibula of the lower calyx can be appreciated in most cases. However, some of the minor calyces and the major lower calyx can be visualized only with a flexible ureteroscope.
Failure of conservative therapy
Unilateral gross haematuria
Unilateral positive cytology
Surveillance - In cases of segmented resection of ureter done for superficial papillary tumour.
OTHER THERAPEUTIC PROCEDURES
Ureteral Catheterisation - In ureteric obstruction, in case of uretero cutaneous fistula, uretero vaginal fistula.
Removal of foreign body - migrated/broken stents.
Tumour resection or fulguration
Dilatation/incision of ureteric stricture
Patient Preparation : History - Detailed previous medical history, especially history of previous pelvic or urinary tract surgery should be obtained.
Radiographic studies : X-ray KUB, Ultrasonography, Intravenous urography should be performed prior to ureteroscopy. A retrograde urography is very helpful just prior performing the procedure.
Informed consent : The patients must be well aware of the chances of success/failure depending on the size of the stone. The need to convert to another procedure; viz ESWL, PCNL, or rarely a laparoscopic or open ureterolithotomy should be explained in complicated cases. Moreover risk of complication should be discussed. Perioperative parenteral antibiotics must be used in a patient undergoing this procedure.
The choice of Anaesthesia : Most lower and mid ureteric stones can be safely performed under regional anaesthesia. Upper ureteric stones should be by and large performed under a general anaesthesia. The reason is because the movements of the upper ureter during respiration under a regional anaesthesia can predispose to complications like perforation.
Fig. 1: Endoscopic anatomy
Most cases can be performed under standard lithotomy position. A modified dorsal lithotomy position with contralateral leg hyper abducted and ipsilateral leg straightened is helpful in some cases. An exaggerated dorsal lithotomy position with both legs hyper flexed to make an angle of 60 degree with the operation table can help in cases of stones just beyond the level of iliac arteries.
A head high position in the lower ureter helps to prevent the migration of stone and conversely a head low position will help in visualization of upper ureter and uretero pelvic junction.
PROBLEMS OF ACCESS
Ureteric Orifice : In the following situation the variation of the ureteric orifice due to anatomical or the pathological causes could make access difficult.
Large median lobe
UV Junction calculus
In an acute ureteric colic, severe spasm can make even passing a preliminary guidewire difficult. The following options can help relieve ureteral spasm.
Lidocaine Jelly (2 ml)
Aminophylline 0.5% (3 ml)
Suppository - Indomethacin
A variety of guidewires may be required to gain proper access. A J tipped glidewire or a zebra wire are currently recommended for access. J tipped heavy duty wire can be replaced for inserting a Double J Stent.
Problems with guidewires can range from
Inability to pass into the orifice
Inability to pass the wire beyond the stone.
Slippage of guidewire
Creation of a false passage/Submucous dissection.
Introduction of ureteroscope right up to the tip of the ureteric orifice or into the lower intramural ureter can straighten the curve and then allow for insertion of the wire under vision. The routine use of a C-arm Image Intensifier will ensure proper position and forewarn in case of expected complication.
Although for diagnostic ureteroscopy routine dilatation of the orifice and the intramural portion of the ureter is not essential, it is an essential aid in cases for ureteric stones.
Dilatation helps in increasing the space available for irrigation and clear views are obtained. Also the intrarenal pressure is kept lower and the spontaneous passage of small fragments of calculi is facilitated.
Non guided systems
•Hydrodilation (ureteromat or use of high pressure bag)
•Graduated ureteral dilators
•Flexible, coaxial, sequential dilators
•Dilating balloon catheters
•Ureteral access sheath
Problems which can occur due to the use of dilators are
•Failure of dilatation
A variety of baskets are now available for stone extraction. The Dormia basket was very popular earlier. Currently the tipless (Zero Tip) Nitinol stone retrieval basket and retrieval forceps are recommended as there is minimum tissue trauma and better stone free results. The various problems encountered with the baskets are
• Stuck basket
• Stone impacted within the basket
Disengaging the basket and passing the ureteroscope by the side and then fragmenting the impacted stone helps prevent further complication.
Stone fragmentation devices
A wide variety of fragmentation devices (ISWL - Intra Corporeal Lithotripsy) are available
• Pneumatic lithoclast
• Holmium - nd yag laser
The pneumatic lithoclast is now indigenously manufactured, widely available and most economical fragmentation device. Problems which could occur with any of the devices include - perforation, bleeding, migration of the stones. The cost of the laser is a severe limitation to its widespread use.
In certain special situations, specific manouevres may be required to ensure success Multiple Ureteric Calculi and Steinstrasse - A placement of percutaneous Nephrostomy drainage tube prior to Ureteroscopy, combination of ureteroscopy with ESWL or PCNL or the use of antegrade ureteroscopy may be required.
In a grossly infected system - placement of a Nephrostomy tube or a DJ Stent preliminarily is safer.
In cases of bilateral obstructive uropathy with grossly dilated, tortuous ureters (mega ureters) - careful step by step ureteroscopy to negotiate difficult curves will help in successful placement of the guidewire and a Stent.
Bilateral Ureteroscopy can be conducted in the same setting if required. A note of caution : the simpler side should be performed first and a safe placement of DJ Stent should be ensured.
This can be performed safely for impacted uretheral stone, bladder stones and if access through the orifice is available even for ureteric stones.
Impacted upper ureteric stone with gross hydronephrosis can be successfully tackled with antegrade ureteroscopy. A carefully planned middle or upper calyceal puncture is required and an access sheath may help prevent acute bending of ureteroscope.
URETEROSCOPY IN PREGNANCY
In selective cases when DJ Stent cannot be passed or a nephrostomy is not acceptable to a patient, a ureteroscopy can be performed for obstructed hydronephrosis due to calculus in pregnancy.
This device is predominantly for diagnostic application. Unclear views and exorbitant costs limits the therapeutic application of this instrument.
The availability of holmium nd yag laser facilitates successful treatment of lower calyceal stones with flexible ureteroscopy.
The success of Ureteroscopy and the prevention of complications can be ensured if one follows the following Ten Commandments.
THE TEN COMMANDMENTS
1. Safety use of visors, glasses, endovision camera, water proof gown, gum boots.
2. Use of Image Intensifier.
3. Make sure accessories are available.
4. Do retrograde urography
5.Regular use of glidewire
6. Dilatation of orifice helpful
7. Take measures to improve vision
8. Be ready to stage procedure - DJ Stenting
9. Picking up fragments not important
10. Recognise and correct complication early
Indeed for all those who have mastered the art of Ureteroscopy the success rate of complete stone eradication is close to 98%.