Another Method for Localization of Radiolucent Urinary Stones during ESWL

  • Soundra Pandyan
  • Published 2010

Abstract

Objectives: 1. To study the feasibility and safety of localization of radiolucent urinary stones during ESWL utilising the refluxing intravesically injected contrast medium along indwelling ureteral stents. 2. To identify the optimum volume of contrast medium and the intravesical pressure at which adequate vesicoureteral reflux sufficient for collecting system opacification occurs. 3. To identify criteria by which successful localization can be predicted. Methods: With antibacterial prophylaxis, hundred mls. of contrast medium diluted with 500 ml normal saline was infused into the bladder through a Y shaped connection attached to a pre-inserted urethral catheter with the other limb connected to a water manometer for the purpose of continuous intravesical pressure recordings. The amount of infused contrast medium and intravesical pressure at which adequate visualization by fluoroscopy occurred was recorded. Successful stone localization was correlated with the infused contrast medium volume, intravesical pressure, infection, stone location, age, weight, stent duration and fluoroscopy time. Results: Forty six patients were studied. Clear stone localization to facilitate shock targeting was achieved in 37 patients (80%). This occurred with a mean contrast volume of 300 ml at 20 cm water mean intravesical pressure. Apart from urinary tract infection which was associated with a significantly lower success rate, there were no other criteria by which success can be predicted. There were no significant complications and all visualized stones disintegrated well and were completely cleared at 3 months. Conclusions: The method is safe, easy, repeatable and suitable for targeting radiolucent urinary stones during ESWL in patients with ureteral stents. Introduction Localization of radiolucent renal and ureteral stones during ESWL is commonly achieved either by ultrasonography or collecting system opacification by contrast media injected intravenously, percutaneously or through ureteral catheters positioned beforehand. Initially, with early experience on the Dornier HM3 lithotriptor, radiolucent stones were considered a relative contraindication to ESWL because of difficult stone localization. Subsequently with the introduction of in-bath ultrasound as adjunct for treatment of radiolucent stones, with fluoroscopy localization lithotriptors, the imaging shortcomings were overcome. Many recent versions of lithotriptors are supplied with a localization system composed of a real time 3.5 mHz. on line monitoring ultrasound transducer which is quite satisfactory for radiolucent renal stone targeting with a reported success rate of 76%. Although reliable for radiolucent renal stone visualisation, ultrasonographic imaging and interpretation needs an experienced operator. 1. Professor of Urology, Dept. of Surgery, Faculty of Medicine, Ribat National University, Khartoum, Sudan 2. Urology Specialist, Assir Central Hospital, Abha, Saudi Arabia Correspondence Address: Prof. Ahmed I.A. Ibrahim, P.O. Box 13066, Khartoum, Sudan Telephone: 00249 912158131 Fax: 00249 183270771 Email: aiaibrahim@yahoo.com It is also known that ultrasonography fails to localize ureteral stones at all levels with an overall reported ultrasonic stone identification rate of only 30% making X-ray fluoroscopy with collecting system opacification mandatory for targeting radiolucent ureteral stones during ESWL. Intravenous injection of contrast media produces only a short lived opacification which may not be sufficient for protracted ESWL. It also requires fluid restriction which contradicts with the adequate hydration recommended for effective stone fragmentation by shock waves. Retrograde opacification requires general or regional anaesthesia for insertion of ureteral catheters which conflicts with minimal invasiveness strategies. Furthermore, follow up of the treatment outcome by fluoroscopy mandates further ureteral catheter insertion or I.V. urography to monitor progression of stone debris. Routine pre-ESWL ureteral stenting had been recommended for bulky and complex renal stones. They are also inserted for patients presenting with completely obstructed kidneys secondary to acutely impacted ureteral stones. Localization of radiolucent ureteral stones for targeting during ESWL had been attempted by using a special double pigtail stent with an extracoil as a pointer for the stone in one published report. With ureteral stenting © Sudan JMS Vol. 2, (o. 2, June 2007 82 vesicoureteral reflux had been shown to occur in the majority of patients at an average bladder pressure of 20 cm water and also in an experimental porcine model. We rather thought of making use of this stenting side effect to opacify the collecting system by intravesical injection of contrast media resulting in a clear collecting system image which we called “refluxogram” for the purpose of localization of radiolucent renal and ureteral stones during ESWL as an alternative technique for the more invasive retrograde opacification by ordinary ureteral catheters. Our initial experience was quite encouraging and therefore we decided to study further the feasibility and safety of this method in patients with radiolucent stones who already had ureteral stents inserted for other reasons. Patients and Methods All patients presenting with radiolucent urinary stones who had an indwelling ureteral stent inserted either for bulky renal stones or ureteral stone impaction were considered for the study. Patients with history of hypersensitivity to contrast media were excluded. Approval of the local ethical committee was obtained. Informed consent was also obtained from all patients. Patients underwent routine investigations namely; urinalysis, urine culture and sensitivity, biochemical workup and imaging by I.V. urography and ultrasonography and computed tomography when necessary. The potential hazards of collecting system opacification through indwelling ureteral stents such as ascending infection and loin and suprapubic discomfort was explained to the patients. Patients with documented bacteriuria were treated by appropriate antibacterials according to urine culture and sensitivity and patients with sterile urine had antibacterial prophylaxis with a single shot 1000 mg. Intravenous ceftazidime. Hundred ml of contrast medium diluted with 500 ml normal saline was infused into the bladder through a Y shaped connection attached to a preinserted urethral catheter with the other limb connected to a water manometer for the purpose of continuous intravesical pressure recordings. Patients were protected against loin and suprapubic discomfort by injecting the minimal volume of the contrast medium that is just adequate for localization and at the lowest possible intravesical pressure. X-ray fluoroscopy was performed at intervals until adequate opacification of the collecting system was achieved at which point the amount of infused contrast medium and intravesical pressure were recorded and further infusion was discontinued. The total fluoroscopy time was also recorded. ESWL was carried out on the Doli Dornier’s lithotripter under sedo-analgesia with 50 mg. pethidine and 10 mg. diazepam Post ESWL stone disintegration and clearance after stent removal was verified by ultrasonography, non contrast CT scan and in few cases with retrograde pyelography. All patients had urine culture before leaving hospital and all complications occurring during or after the procedure were recorded. The outcome of stone treatment using this procedure was assessed using the following parameters: 1. Number of ESWL shocks and number of sessions if more than one session was needed. 2. Stone clearance at 3 months following ESWL. 3. Total fluoroscopy time. 4. Complications such as haematuria, septicaemia, loin discomfort, postoperative bacteriuria, dysuria, suprapubic discomfort, hypersensitivity to the contrast medium and any other complications. 5. Mean intravesical pressure and infused contrast volume at which opacification by vesicoureteral reflux occurs. Results A total of 46 patients were included in the study, 38 males and 8 females. Mean age was 51+ 16 (range 22 to 90 years) and the mean weight was 81+ 17 Kg (range 53-120). A total of 31 renal stones and 9 ureteral stones were treated and the mean stent duration was 17+ 21 days. Mean fluoroscopy time was 125+ 62 minutes, mean Intravesical pressure was 21+ 9 (range 8-54 cm water and mean contrast volume infused was 295+ 100 ml. (range 150-600 ml.). Mean total duration of ESWL was 54+ 17 min (range 21-100 min). Mean number of sessions was 1.6+ 0.7 (range 1-4) and mean number of shocks was 2963+ 476 (range 1000-4000). Table 1 shows the location of the stones in the urinary tract. Table 1: Stone location in the urinary tract Location of the stone No. (%) Single renal stone 23 (50) Multiple renal stones 6 (17.4) Upper ureteral stone 1 (2.2) Middle ureteral stone 8 (17.4) Lower ureteral stone 5 (10.9) Combined renal and ureteral stones 1 (2.2) Localization of Radiolucent Urinary Stones, IbrahimA I & Pandyan S

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@inproceedings{Pandyan2010AnotherMF, title={Another Method for Localization of Radiolucent Urinary Stones during ESWL}, author={Soundra Pandyan}, year={2010} }