Ureteroscopic Management of Proximal Ureteric Calculi Using Stone Cone

ABSTRACT

Aim of the work: To assess the efficacy and safety of Stone Cone during ureteroscopic pneumatic lithotripsy of proximal ureteric calculi.

Setting and design: From June 2009 to June 2010, 119 patients were included and underwent ureteroscopic management of proximal ureteric calculi with the help of Stone Cone and pneumatic disintegration.

Material and method: Our patients were divided into 2 groups. Ureteroscopic management of proximal ureteric calculi with pneumatic lithotripsy was done in group 1, and ureteroscopic management of upper ureteric stones with the help of Stone Cone and pneumatic lithotripsy was done in group 2.

Results: Patients were divided into 2 groups. Group 1 included 62 patients that underwent standard ureteroscopic pneumatic lithotripsy without Stone Cone. Group 2 included 57 patients that underwent pneumatic lithotripsy using Stone Cone as ureteral occlusion during ureteroscopy. The success rate was 87% in group 1 and 94.7% in group 2. The complication rate ranged from 3.5 to 8%. There were 4 cases of haematuria (6.4%) and one case of ureteral perforation (1.6%) in group 1. In group 2, 2 cases (3.5%) of haematuria occurred. Operative time was highly significant in group 2 and not in group 1; it was 20 to 35 minutes in group 2 versus 30 to 50 minutes in group 1.

Conclusion: Stone Cone is an instrument used during ureteroscopi lithotripsy of proximal ureteric calculi. It can be considered a very effective instrument in blocking the upward migration of ureteric calculi, enabling its safe removal.

Ahmed Shelbaia, Sherif Abd ELRahman, Ali Hussein

Submitted June 15, 2011 - Accepted for Publication Sept 12, 2011

KEYWORDS: Proximal ureteric calculi; Stone Cone; Pneumatic lithotripsy; Ureteroscopy

CORRESPONDENCE: Ahmed Shelbaia, Urology Department, Cairo University Hospital, Borg El Atbaa, Faisal Street, Cairo, Egypt (ahmedshelbaia2007@hotmail)

CITATION: Urotoday Int J. 2011 Dec;4(6):art68. http://dx.doi.org/10.3834/uij.1944-5784.2011.12.01

INTRODUCTION

The developments of semi-rigid and flexible ureteroscopy have dramatically increased the success rates and safety of performing invasive procedures in the ureter. A variety of intracorporeal lithotripter devices have also been developed to enhance the efficacy of stone fragmentation. Despite these improvements, the optimal treatment of ureteral stones, especially with large proximal ureteral stones, remains controversial. The 2007 guidelines for the management of ureteral calculi according to the AUA/EAU recommend that patients are informed that ureteroscopic stone removal (URS) is associated with a better chance of becoming stone free with a single procedure [1].

The major concern for ureteroscopy is complications due to the procedure. Complications such as ureteral avulsion, intussusceptions, urosepsis, and steinstrasse are rare [2], especially due to small-caliber, semi-rigid and flexible ureteroscopy.

Minor complications, such as perforation, urinary extravasations, false passage, mucosal abrasion, and bleeding, are not common [3,4].

Many randomized studies have shown that routine use of stenting after uncomplicated ureteroscopy is not recommended [5].

Ureteroscopy with various lithotripters for proximal ureteral stones has shown varied results. The stone-free rate with electro-hydraulic lithotripsy (EHL) was over 90% [6,7], but the traumatic effect was the main problem. Because of retrograde stone displacement to the kidneys, the stone-free rate with Swiss LithoClast lithotripsy was around 70% [8,9]. With pulse-dyed laser lithotripsy, stone-free rates might reach 95% [10,11], but the disadvantage is the expense. As to Holmium: YAG laser lithotripsy, the stone-free rates are around 87 to 97% [12,13,14,15] in treating impacted proximal ureteral stones of >1 cm. Homium: YAG laser lithotripsy revealed excellent stone-free rates (84 to 96.2%) in endoscopic procedures, and it was more cost-effective than extracorporeal shock wave lithotripsy (ESWL) [16]; however, the high cost of the equipment is the most debated issue. The flexible ureteroscope is largely responsible for improved access to the proximal ureter. Superior stone-free rates have been achieved using flexible URS (87%) compared with rigid or semi-rigid URS (77%). These stone-free rates are comparable to those achieved with SWL [2].

Upward stone migration during intracorporeal lithotripsy occurs in 5 to 40% of cases. The risk of upward migration is influenced by the pressure of the irrigant fluid, type of energy source used for intracorporeal lithotripsy, the site and degree of calculus impaction, and the degree of proximal ureteral dilation [17]. Smaller stones and greater proximal ureteral dilation or hydroureteronephrosis increase the rate of stone migration. As a solution to this problem, new instruments have been developed to prevent upward migration of ureteral stones and enables safe extraction of stone fragments during ureteroscopic lithotripsy [17,18,19]. We present our experience with the use of a Stone Cone device during intracorporeal lithotripsy of upper ureteral calculi.

MATERIALS AND METHODS

In this prospective study, 119 patients were included and had undergone ureteroscopic management of proximal ureteric calculi in our institution between June 2009 and June 2010 (90 males and 29 females), with a mean age of 42 + 10 years (ranging between 18 and 59 years), and have a single proximal ureteric stone between 10 and 15 mm. The patients were prospectively evaluated and the location of the stone was confirmed by intravenous urogram (IVU) or non-contrast spiral computed urography (CT). Patients who were pregnant, had bleeding disorders, or a previous history of ipsilateral ureteral stones and ureteral surgery (open or endoscopic) were excluded from the study. Our patients were divided into 2 groups. Group 1 included 62 patients who underwent standard ureteroscopic pneumatic lithotripsy without Stone Cone. Group 2 included 57 patients underwent pneumatic lithotripsy using Stone Cone (nitinol stone retrieval coil) as ureteral occlusion during ureteroscopy.

All patients underwent ureteroscopy under general or regional anaesthesia using 8.5 Fr semi-rigid (Storz) ureteroscope.

In group 1, URS was performed after dilatation of the ureteric orifice into 12 Fr using Teflon dilators, and then pneumatic lithotripsy (Swiss lithoclast) was performed for fragmentation of the stone < 2 mm.

In group 2, Stone Cone, using 3 Fr with a coil size of 10 mm, was inserted cystoscopically under fluoroscopic guidance for ureteral occlusion to bypass the stone. After the tip of the carrying catheter was passed above the stone into the proximal ureter, the device was then activated and pulled back to fit over the stone. Then URS and fragmentation of the stone using pneumatic lithotripsy were performed. When the stone was fragmented, the device was pulled under vision to extract the fragments. Success resulted when the stone completely fragmented without upward migration of the stone fragments, and follow-up X-rays showed clearance of the stone after 1 and 3 weeks.

Operative time, success rate, hospital stay, and postoperative complications were reported and compared between the 2 groups.

Follow-up of the patients was performed with X-ray film of the urinary tract (KUB) after 24 hours to exclude stone migration and assess the clearance of stones. Another was performed after 1 week. Non-contrast CT or plain radiograph was done after 3 weeks, postoperatively, to assess the stone-free rate. Follow-up by non-contrast CT or KUB was performed every 6 months for 1 year. Operative time, success rate, hospital stay, and postoperative complications were reported and compared between the 2 groups in Table 1.

STATISTICAL ANALYSIS

A statistical comparison between group 1 and group 2 was done by the use of mean ± standard deviation, chi-square test, and the Fisher 2-sided exact test where p < 0.05 was considered statistically significant.

RESULTS

One hundred and nineteen patients underwent ureteroscopic lithotripsy for proximal ureteric stones. They were randomly distributed into 2 groups. Group 1 included 62 patients who underwent standard ureteroscopic pneumatic lithotripsy without Stone Cone. Ten cases in this group had stones close to 15 mm. The operation was successful in 87% (54 out of 62) patients. Two cases had stone migration up to the kidney (3.2%) and ESWL was done after 3 weeks. Residual fragments up to 5 mm occured in 5 cases and DJ stent was inserted (reteroscopy was done after 2 weeks in 4 cases and ESWL was done in the last case). Perforation of the ureter occurred in one case and DJ stent was inserted for 3 weeks. Mild haematuria occurred in 4 cases and cleared a few days postoperatively. Operative time was 30 to 50 minutes (range) with a mean operative time 35.3 + 7.2 minutes. Stenting was done in all success cases for 24 hours till the urine became clear. The hospital stay was 24 to 48 hours with an average of 36 hours.

Group 2 included 57 patients who underwent pneumatic lithotripsy using Stone Cone as ureteral occlusion during ureteroscopy. Seven cases in this group had stones close to 15 mm. The success rate was 94.7% (54 out of 57). There were no cases of stone migration. Residual fragments up to 5 mm occured in 3 cases and DJ stent was inserted (ureteroscopy was done after 2 weeks in 2 cases and ESWL for 1). No cases of perforation occurred. Mild haematuria occured in 2 cases. Operative time was 20 to 35 minutes (range) with a mean operative time 29.3 + 8.4 minutes. Stenting was done in all success cases for 12 hours. The hospital stay was 12 to 36 hours with an average of 24 hours till urine became clear.

DISCUSSION

URS of ureteral stones has become more common in the last 10 to 15 years. It has become more practical and tolerable, and with higher success results. URS has become the standard procedure in the management of ureteral stones, especially with a combination of auxiliary procedures [2,6,7]. Advances in endoscopic equipment has increased the indications of URS, so that proximally ureteric stones can be managed successfully, in addition to distal and mid-ureteric stones [8].

In our study, 119 patients with proximal ureteric stones have been managed by semi-rigid ureteroscopy successfully. The success rate was 87% in group 1 and 94.7% in group 2, and this is comparable to previous studies. The complication rate ranged from 3.5 to 8% with 4 cases of haematuria (6.4%) and 1 case of ureteral perforation (1.6%) in group 1. In group 2, 2 cases of haematuria (3.5%) occurred. Operative time was highly significant in group 2 rather than group 1; it was 20 to 30 minutes in group 2 versus 30 to 50 minutes in group 1. The success rate of the clearance of proximal ureteric stones has increased up to 98% with a complication rate between 3 and 9% [20]. Several studies reported that the clearance rate of stones < 10 mm treated by URS and a Holmium: YAG laser was 100% versus 80%, with ESWL and with stones > 10 mm. The clearance rate was 93% with URS and 50% in ESWL [21]. The use of smaller and fine equipment let the urologist choose between URS and ESWL in the management of ureteric stones.

Widespread use of different lithotripsy options, such as pneumatic and the Holmium: YAG laser, make ureterolithotomy easier than before.

Some studies have shown that pneumatic lithotripsy is well-tolerated and cost effective, and it has a stone clearance rate of up to 85% [22,23].

The use of semi-rigid ureteroscopy with pneumatic lithotripsy in the management of proximal ureteric calculi was found to be safe and effective, but the use of flexible URS with a Holmium: YAG laser and ESWL was more effective with less complications and a lower percentage of stone migration [24].

The use of Stone Cone with URS in our study increased the success rate up to 94.7% and prevents stone migration with few complications. Our results were comparable to previous studies. Stone Cone is an instrument used during ureteroscopic lithotripsy for proximal ureteric calculi. It can be considered a very effective instrument that blocks the upward movement of ureteric stones and aids in safe stone removal.

We recommend the ureteroscopic management of proximal ureteric calculi using Stone Cone and pneumatic lithotripsy.

REFERENCES

Preminger GM, Tiselius HG, Assimos DG, Alken P, Buck C, Gallucci M, et al. 2007 guideline for the management of ureteral calculi. J Urol. 2007;178:2418-2434.

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