A preliminary study of the variability in location of the ureteral orifices with bladder filling by fluoroscopic guidance: the gender difference

The optimal stent pusher position to achieve successful ureteral stent insertion under fluoroscopic guidance

Objective

To examine factors to predict the optimal stent pusher position when inserting ureteral stents under fluoroscopy.

Methods

We retrospectively reviewed 327 patients who underwent ureteral stent insertion. We considered the pubic bone as a useful anatomical landmark to insert ureteral stents under fluoroscopic guidance. Thus, we categorized patients into three groups (proximal, middle, and distal groups) according to the position of the radiopaque tip of the push catheter when inserting the ureteral stent. Success was defined as a completely curled ureteral stent tail. We compared stent insertion success rates among the three groups. A multivariate analysis was performed to identify the factors affecting stent insertion success.

Results

In men, 36 (63.2%) cases were deemed successful in the proximal group compared with 40 (80.0%) cases in the middle group and 12 (20.7%) cases in the distal group (p<0.001). In women, 26 (45.6%) cases were deemed successful in the proximal group compared with 54 (98.2%) cases in the middle group and 38 (76.0%) cases in the distal group (p<0.001). With the multivariate analysis, the stent pusher position was the most significant factor influencing successful stent insertion (men: odds ratio 6.00, 95% confidence interval 2.66-13.51, p<0.001; women: odds ratio 37.80, 95% confidence interval 4.94-289.22, p<0.001).

Conclusion

The position of the stent pusher affects stent insertion success. The middle of the pubic symphysis is the optimal position for the radiopaque tip of the pusher when inserting ureteral stents under fluoroscopic guidance.

Simplified method using kidney / ureter / bladder x-ray to determine the appropriate length of ureteral stents

Purpose:

To investigate a method to determine the appropriate length of ureteral stents, given that the stent length may lead to exacerbation of urinary symptoms if the stent crosses the bladder midline.

Materials and Methods:

We retrospectively reviewed the position of the distal curl of the ureteral stent using kidney/ureter/bladder (KUB) radiographs after ureteroscopic lithotripsy in 165 patients who underwent placement of 24- or 26-cm ureteral stents. According to the KUB findings, we categorized the position of the distal curl of the ureteral stent into two groups. In Group 1, the stents did not cross the midline (appropriate length); in Group 2, the stents crossed the midline (inappropriate length). We assessed several patient parameters (sex, height, body mass index, and stone side) and the index of ureteral length using KUB radiographs (“C-P”) and computed tomography (CT, “P-V”). Multivariate analysis was performed to identify the most significant factors affecting the position of ureteral stents. We also calculated the cutoff points of the receiver operating characteristic (ROC) curve of C-P and P-V for the position of ureteral stents.

Results:

The multivariate analysis showed that C-P was the most significant factor affecting the position of ureteral stents (p < 0.001) in patients with 24- and 26-cm ureteral stents. Comparison of the ROC curves of C-P and P-V showed that C-P was superior to P-V (p < 0.01) in patients with 24- and 26-cm stents.

Conclusion:

The use of KUB radiographs was effective and simple in determining the appropriate length of ureteral stents.

A ureteral stent crossing the bladder midline leads to worse urinary symptoms

Introduction

To investigate the correlation between the position of a ureteral stent and stent-related symptoms, excluding the influence of ureteroscopic maneuvers.

Material and methods

From January 2016 to December 2016, we analyzed 130 patients who placed a ureteral stent before ureteroscopic lithotripsy (URSL). A total of 108 patients were enrolled, including 77 (71.3%) men and 31 (28.7%) women, and the mean age was 58.9 ±14.3 years. On the day before URSL, plain radiography (kidney, ureter, bladder X-ray [KUB]) was used to confirm the stone location and ureteral stent position. According to KUB, we defined the crossing midline group as when the distal loop of the ureteral stent was crossing the bladder midline, and the not crossing midline group as when the distal loop of the ureteral stent was not crossing the bladder midline. We assessed urinary symptoms of the two groups using the overactive bladder symptom score (OABSS) on the day before URSL.

Results

The crossing midline group had a worse total OABSS (p <0.001) and worse scores for each item of daytime frequency (p = 0.047), nocturia (p <0.001), urgency (p = 0.002), and urgency incontinence (p = 0.045) than did the not crossing group. In multivariate analysis, stent position had the strongest association with the total OABSS (p = 0.002) among the other factors of age, sex, body mass index, stent side, stent diameter, stent length and stent indwelling time.

Conclusions

This study shows that a ureteral stent crossing the bladder midline leads to worse urinary symptoms. Choosing the appropriate stent length for each patient is important for improving stent-related symptoms.

Intraoperative Radiographic Determination of Ureteral Length as a Method of Determining Ideal Stent Length

INTRODUCTION

Accurate determination of ureteral length (UL) and appropriate stent length remains a challenge. The objective of this study was to describe an intraoperative technique to measure UL and determine appropriate stent length, and to compare this technique with other methods of determining appropriate stent length.

METHODS

Patients undergoing ureteroscopy requiring postoperative stenting and who had a preoperative CT were prospectively identified. Gender, age, height, body mass index, L1 to L5 lumbar height on CT, and surgeon's estimate of UL were recorded. UL was measured using four methods: direct measurement with a ureteral catheter, ureteropelvic junction (UPJ) to ureterovesical junction distance on axial and coronal CT, and using a novel intraoperative radiographic technique. Radiographic measurement was performed using a radiographic nipple marker affixed to the skin over the ureteral orifice (UO) and an angiographic catheter with radiopaque markings at 1 cm intervals. UL was the distance from the UPJ to the marker at the UO measured using the catheter markers. Correlation between direct measurement and the recorded variables and methods of ureteral measurement were calculated. Stent length was chosen based on radiographic measurement. Stents were deemed of appropriate length if they showed a proximal coil in the renal pelvis and a distal coil in the bladder without crossing midline.

RESULTS

Twenty-five ureters from 23 patients were included. Radiographically measured UL was strongly correlated with direct measurement. (r = 0.873, p < 0.01). Coronal and axial CT ULs were significantly associated with direct measurement (p < 0.05). Height, lumbar height, and surgeon's estimate of UL were not. Stents were deemed of appropriate length in 23/25 cases (92%).

CONCLUSIONS

This new method for radiographic UL measurement is strongly correlated with directly measured UL. A length of stent chosen based on radiographic UL resulted in an appropriate stent length.