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TRICKS OF THE TRADE FOR UPPER THIRD ENDOSCOPY

SHIVADEO S BAPAT

Consultant Urologist, Joshi Hospital and Ratna Memorial Hospital, Shivajinagar, Pune.
With the availability of excellent modern imaging facilities, slender ureteroscopes, (rigid and flexible) and stone crushing devices like the pneumatic crushers or Holmium Laser, it is now possible to Endoscopically visualize the entire ureter, take biopsy, incise or resect and tackle all types of stones at any level in the ureter. This indeed is a very bold statement. We also have to realize the fact that there will be some causes where you will not be able to achieve success inspite of having all the facilities at your command. This is where experience counts. One should never give 100% guarantee of success in ureteroscopy in all the cases. There are bound to be some cases where the procedure may fail.

We will discuss this topic under two heads : General considerations and Specific points.

GENERAL CONSIDERATIONS

1.Before anyone attempts to perform ureteroscopy (URS) for the upper third ureter it is essential for the operator to be well versed in the art of lower third ureteroscopy. It is indeed a tricky job and slightest misadventure may land the operator in great difficulty and cause a lot of suffering to the patient.

2.Commonest indication for upper third URS is the stone disease. Other indications are stricture and rarely malignancy.

3.It is essential to take a stock of all the endoscopic armamentarium at your disposal. One of the most important requirements for upper third URS is the availability of C-arm image intensifier and a proper operating table where the C-arm can be used. Some centres may not have C-arm facility in the operating room. In such cases an image intensifier fitted to a regular X-ray table should be used.

4.Slender and long 7/12 or 8/14 Fr. URS is the most suitable instrument. If you have a flexible URS it will be a great asset.

5.Guide wires of different sizes are essential. One of the best guide wires for URS is the ‘Zebra’ or ‘Cobra’ guide wire. The beauty of this guide wire is the soft tip and the stiff body. In most cases it can be easily negotiated by the side of an impacted stone. This guide wire can be reused many times after gas sterilisation and thus it is very economical.

6.During URS, whenever an operating instrument is passed through the channel of the URS, the flow of the irrigating fluid slows down. At this time it is very essential to have a mechanism by which adequate flow of irrigating fluid is maintained. ‘Path finder’ is one such item. We use a simpler system. A sterile wide bore needle (10 to 12 SWG) attached to a blood pressure pump is thrust in the top of a 2000 ml thick walled PVC saline bottle. By raising the pressure within the saline bottle adequate flow with pressure can be generated at your command.

7.Energy sources for crushing stone should be available. Commonest is the ‘Pneumatic’ crusher. If the facility of Holmium laser is available, it is the most ideal. It has double benefit. (a) It can crush the calculi of any composition or hardness and (b) It can perform cutting jobs with equal ease. Due to impact of the pneumatic crusher the chances of the upward migration of the stone is common. With Holmium laser this problem is uncommon.

8.A variety of baskets should be available. Ideal for URS is the ‘retractable’ basket. In this variety the tip of the basket is very thin and it can be removed through its sheath. Stabilization of the stone prior to crushing is important. Some times only a guide wire slips above the stone. Under vision, the sheath of the basket can be slipped over this guide wire and the guide wire removed. Through the sheath, the basket can be easily passed proximal to the stone and then the stone can be stabilized. Among the baskets ‘Segura’ parallel flat wire basket is the most ideal.

9.Anaesthesia plays an important role in the endoscopic management of stones in the upper ureter. General anaesthesia with controlled respiration is ideal. Stones in the upper third tend to move up and down with each respiration. This may pose a problem in accurately hitting the stone. You can request the Anaesthetist to give periods of apnoea during which the stone can be crushed with minimal difficulty. Further more you should request the Anaesthetist to inject Frusemide soon after the upper ureter is entered. This definitely prevents smaller fragments of the stones to fly up. It is advisable to have 10° to 15° head low position. Proximally migrating stone fragments would tend to settle in the top calyx.

10.During URS considerable amount of irrigating fluid is used within the ureter that flows down the ureter in to the bladder. Various sheaths are available to drain the fluid from the bladder and prevent over distension. We use a very simple and inexpensive technique. Pass a simple PVC Nelaton catheter (8 Fr.) per urethra in to the bladder. Introduce the URS in to the urethra by the side of the Nelaton catheter. Let it stay there till the URS procedure is completed. It will keep on draining the bladder and prevent over distension.

11.Even if the urine examination reveals no infection on culture studies, it is safer to consider all stones cases as potentially infected. Antibiotics should be administered in all cases. Those who have documented infection, in addition to the appropriate antibiotic, patient should be given pre, peri and post-operative metronidazole or tinidazole. Administration of these drugs helps in the prevention of the most dreaded complication of gram-negative septicaemia.

SPECIFIC POINTS

1.It is essential to know the exact anatomy of ureter, its curvatures and kinks. If earlier imaging with IVU has revealed the details clearly, then you can proceed with URS straight away. Otherwise it is important to perform a ureterogram prior to starting the procedure of URS.

2.First and the foremost important act in URS is to get a safety guide wire up in to the ureter. It should be safely parked within the proximal renal collecting system and should be left there till the end of URS procedure. While pushing the guide wire up, it is also important to note that at the level of the stone, it may create a false passage. This fact should be borne in mind all the time. Position of the proximal part of the guide wire as seen on fluoroscopy will give some indication of its improper placement.

3.As mentioned already, it is very important to have C-arm facility during URS. But some Urologist perform URS without the aid of the C-arm. For such Urologists I would like to suggest following procedure.

4.Dilate the lower ureter to at least 12 to 15 Fr. before advancing the URS up the ureter. During actual crushing of the stones, the vision through the URS becomes blurred due to dust particles and may be a little bit of blood. More irrigating fluid is pumped in, at times with a little pressure. This extra load of fluid is likely to pass up in to the renal collecting system and over distend it. But if the lower ureter is properly dilated the extra fluid will flow down the ureter into the bladder easily and avoid over distension.

5.Inability of advancing the URS within the ureter is noticed often in those cases who are obese and those who have had earlier open surgery on ureter. Passage of additional guide wire through the URS and then advancing the URS over the second guide wire may over come the problem. These problems are usually encountered in the lower ureter. It is very important not to force the URS up the ureter. You may perforate or avulse the ureter. At times the URS can get bent and be badly damaged. In such cases flexible URS is ideal.

6.If one faces such a situation, it is advisable to pass a double J stent (DJ) over the pre-existing safety guide wire and abandon the procedure of URS. Call the patient back after a fortnight and repeat the procedure. Chances of success are very high at the second stage.

7.In long standing impacted stones, the proximal ureter is not only dilated but it is also tortuous. It is often seen that at the level of the stone the proximal ureter is almost at right angle to the lower ureter. It is very difficult to slip the guide wire up the stone in such cases. In our experience we have found that with patient manipulation, guide wire can be managed to slip in to the proximal ureter. Once it is up, the stiff body of the guide wire automatically straightens the ureter and brings the stone in line with the URS. Another item that can help you in such a situation is the ‘COBRA’ ureteric catheter. This special catheter has a fixed memory bend near its tip (like the selective angiography catheter). It can be manipulated in to the bent ureter and the guide wire then can be slipped up the ureter.

8.It is very important to know the details about the stone and the upper tract dilation. Stones that have been impacted for some time invariably have severe proximal dilation along with considerable oedema of the ureteral mucosa. At times these oedematous fronds will completely block the view of the stone, although on imaging you will find that the stone is just next to your ureteroscope. In such cases gentle pushing aside of the oedematous fronds will bring the stone in your vision. If Holmium laser is available, very carefully, the floating free ends of the projecting oedematous fronds can be lased to expose the lower part of the stone. Once the stone is visualized, crushing can be started.

9.If a basket is used to stabilize the stone, it is possible to break one or two wires of the basket due to impact of the pneumatic probe. Such an accident is more likely when Holmium laser energy is used to fragment the stone. However, it is also a fact that whenever Holmium laser energy is used to fragment the stone, one does not need to stabilize the stone, as the proximal movement of the stone is very minimal.

10.Perforation of the ureter is one of the most common injuries during URS procedure. With pneumatic crushers one is likely to produce a hole in the ureter. As there is no thermal damage to the surrounding tissues, such perforation injuries usually do not pose any problem and heal well without any stricture formation. Energies like the electro-hydraulic stone crushers, where there is a thermal blast effect, injuries to the ureter have been reported. Holmium laser if used improperly, there is a definite chance of damage to the ureter. But the effect of the Holmium laser is restricted only to a distance of one millimeter. Serious perforation of the ureter is unlikely, provided the operator uses utmost care during the use of Holmium laser energy. Most important point is to recognize the complication early. Judge the damage and then decide whether to proceed with the URS or to stop and leave a DJ.

11.Proximal migration of the stone fragments or the entire stone is a definite possibility during URS. These events are more commonly observed during crushing of the stones by Pneumatic energy that works by directly hitting the stone to pulverize it. There are various techniques to prevent this problem. If the operator realizes that the stone is migrating, stop the flow of the irrigating fluid, remove the pneumatic stone crushing probe and advance a slender (3 Fr.) basket through the operating channel of the URS. Under vision catch the stone securely within the basket wires. From now on there are two options. (a) Only remove the PVC sheath of the basket from the URS, leaving the wire basket with the trapped stone as it is. You will have to un-screw the controlling mechanism of the basket to facilitate the sheath removal. If the operating channel of the URS permits, pass the probe of the pneumatic stone crusher by the side of the basket wire. You may have to change to a finer probe to facilitate its introduction through the working channel of the URS. The free end of the basket wire is held by the assistant to stabilize the basket. Once the probe comes under vision the crushing can be started. If you are using Holmium laser, the laser fibre being slender can be passed by the side of the basket wire easily. (b) If you do not have a retractable basket or the working channel of the URS does not allow the passage of two instruments simultaneously, then un-screw the controlling mechanism of the basket and remove the URS carefully, leaving the entire basket with the trapped stone within the ureter. Re-introduce the URS back in to the ureter up to the stone by the side of the pre-existing basket and crush the stone within the basket. Your assistant will have to stabilize the basket from outside. Care should be taken to crush the stone and avoid hitting the wires of the basket. In such a situation the parallel flat wires of the Segura basket are ideal. Keep the flow of the irrigating fluid to a bare minimum.

12.Even after taking all the precautions, still there is a chance for larger stone fragments to fly up in to the kidney. If your anaesthetist has given 10o to 15o head low position (as mentioned earlier), it is very likely that these fragments would fly in to the top calyx. You can easily enter the kidney with URS and locate the stones in the top calyx and crush them easily. Availability of simultaneous fluoroscopy will greatly help in locating the fragments. If a flexible URS and Holmium laser is available your job will be much easier.

13.If there is difficulty in entering the renal pelvis, there is a very simple manoeuvre that can help you. Request one of the circulating attendants in the operating room to push the kidney anteriorly. Fold the fingers to make a fist, push the fist under the lumbar area and then extend the wrist. This manoeuvre will push the kidney forwards and you will be able to enter the renal pelvis easily.

14.Finally, when the decision is taken to withdraw the URS, pull it out very gently with freely flowing irrigating fluid. You must watch that the ureteral wall is receding easily from the telescope. If at any time you realize that the ureteric wall is not receding freely and in fact it is following your telescope - STOP - URS withdrawal. If you persist in removal, you may avulse the ureter. This problem is noticed if you do not dilate the lower ureter initially or a fragment of the stone is impacted by the side of the URS in the lower ureter. Increase the irrigating fluid pressure to distend the ureter. Move the URS up for some distance, rotate it on its axis and then repeat the withdrawal. At last, remove the safety guide wire from the ureter to give a little extra space.

In difficult situations, never fight with the stone. Accept defeat and come our gracefully.


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