Correlation of ureteric length with anthropometric variables of surface body habitus

Lower urinary tract effects of ureteral stent length and intravesical position

PURPOSE

Ureteral stents can cause lower urinary tract problems such as stent-related irritative symptoms and urinary tract infections. This study aimed to determine the lower urinary tract effects of ureteral stent length and intravesical position in children.

METHODS

Patients who underwent double-J stenting after urological procedures between January 2017 and January 2022 were included in the study. The patients were assessed in terms of age, irritative symptoms, urinary tract infections, and stent length. The intravesical position of the ureteral stents was grouped as cross-trigonal and ipsilateral. The distribution of irritative symptoms, frequency of urinary tract infections and stent length were analyzed according to intravesical location.

RESULTS

A total of 47 patients were included in the study. The median age was 5 years (range: 1-16). Cross-trigonal stent position was significantly associated with symptoms of urgency (p = 0.046), suprapubic pain (p = 0.002), and lower mean age (p = 0.004). Urinary tract infections were more frequent in patients whose placed stents were longer than recommended (p < 0.001) or were in cross-trigonal position (p = 0.043).

CONCLUSION

Our results suggest that stent-related irritative symptoms and urinary tract infections can be reduced in pediatric patients using a suitably sized ureteral stent and considering its intravesical position.

Instrumental dead space and proximal working channel connector design in flexible ureteroscopy: a new concept

Objective

The objective of this study was to evaluate a new concept in flexible ureteroscopy: instrumental dead space (IDS). For this purpose, various proximal working channel connector designs, as well as the impact of ancillary devices occupying the working channel were evaluated in currently available flexible ureteroscopes.

Design and methods

IDS was defined as the volume of saline irrigation needed to inject at the proximal connector for delivery at the distal working channel tip. Because IDS is related to working channel diameter and length, proximal connector design, as well as occupation of working channel by ancillary devices, these parameters were also reviewed.

Results

IDS significantly varied between flexible ureteroscope models, ranging from 1.1 ml for the Pusen bare scopes, to 2.3 ml for Olympus scopes with their 4-way connector (p < 0.001). Proximal connector designs showed a high degree of variability in the number of available Luer locks, valves, seals, angles, and rotative characteristics. The measured length of the working channel of bare scopes ranged between 739 and 854 mm and significantly correlated with measured IDS (R² = 0.82, p < 0.001). The coupling of scopes with an alternative ancillary proximal connector and the insertion of ancillary devices into the working channel significantly reduced IDS (mean IDS reduction of 0.1 to 0.5 ml; p < 0.001).

Conclusions

IDS appears as a new parameter that should be considered for future applications of flexible ureteroscopes. A low IDS seems desirable for several clinical applications. The main factors impacting IDS are working channel and proximal connector design, as well as ancillary devices inserted into the working channel. Future studies should clarify how reducing IDS may affect irrigation flow, intrarenal pressure, and direct in-scope suction, as well as evaluate the most desirable proximal connector design properties.

Prospective randomized controlled trial comparing a ureteral stent crossing versus not crossing the bladder midline

PURPOSE

To evaluate the correlation between the position of a ureteral stent and stent-related symptoms in a single-center randomized study.

METHODS

A total of 113 patients who required ureteral stent placement after lithotripsy were randomized at a 1:1 ratio into groups with stents crossing and not crossing the bladder midline. The ureteral stent remained in place until postoperative day 14, when we obtained each patient's International Prostate Symptom Score (IPSS), overactive bladder symptom score (OABSS), and visual analog scale (VAS) pain score.

RESULTS

Comparing changes from baseline IPSS and OABSS scores between the two groups, the midline crossing group had a worse OABSS total score than the not crossing group (3.0 ± 2.8 vs. 2.0 ± 3.3; p = 0.032). There was no significant difference between the crossing and not crossing groups in IPSS total score (6.8 ± 7.6 vs. 5.1 ± 8.5; p = 0.14). The OABSS urgency mean score was significantly lower in the not crossing than in the crossing group (1.1 ± 1.8 vs. 1.6 ± 1.8; p = 0.042). However, there was no significant difference between groups for remaining items of the IPSS and OABSS and the mean VAS total pain score (1.9 ± 2.7 vs. 1.2 ± 1.9; p = 0.14).

CONCLUSION

A ureteral stent that crossed the bladder midline led to worse urinary symptoms. Choosing the appropriate stent length for each patient is important to minimize stent-related symptoms.

TRIAL REGISTRATION DATE

1 October 2018; number: UMIN000034067.

Evaluation of Patient Factors That Influence Predictive Formulas for Determining Ureteral Stent Length When Compared to Direct Measurement

Objectives: To compare direct ureteral length measurements with predictive formulas used for the preoperative assessment of ureteral length, and to evaluate patient factors that impact the accuracy of these predictive formulas. Methods: Patients undergoing ureteral stenting for benign and malignant indications were included. Clinical factors analyzed were gender, race, height, weight, prior abdominal or pelvic surgery, radiation therapy, pelvic organ prolapse (POP), laterality, hydronephrosis, and pre-existing ureteral stent. Three predictive formulas and a common height-based formula were used. Direct ureteral measurements were obtained with a ruled 5F ureteral catheter. Predictive formulas were compared with direct ureteral measurements using scatterplot and Spearman's correlation coefficient. Univariate and multivariate logistic regressions were used to evaluate patient factors associated with ≥2 cm deviation from direct ureteral measurements. Results: A total of 108 patients (134 ureters) were analyzed. All predictive formulas correlated poorly with direct ureteral measurements, although as much as 60% of ureteral stent lengths were accurately predicted. Several patient factors significantly impacted accuracy of formulas: male gender (p = 0.04), POP (p = 0.05), body mass index (BMI) ≥25 (p = 0.03), and pre-existing ureteral stent (p = 0.05). Conclusion: Our study suggests that predictive formulas for ureteral stent length have poor accuracy when compared to direct measurement, especially for patients with elevated BMI and POP. Our institution considers direct ureteral measurement the gold standard for determining ureteral stent length-a method that is universally applicable and independent of patient factors.

Korean ureter length: A computed tomography-based study

Purpose

We measured ureter length in healthy Koreans using reformatted computed tomography (UL_CT) and found ways to indirectly estimate ureter length by measuring LL_CT, the length between the ureteropelvic junction and the ureterovesical junction, and standing and sitting height.

Materials and Methods

A total of 508 ureters of 254 healthy patients (median age, 55.0 years; 148 males and 106 females) were included in this retrospective study. UL_CT, LL_CT, and sitting and standing body height were measured.

Results

The mean left and right UL_CT were 25.2±2.2 and 25.0±2.2 cm, respectively. The mean left and right LL_CT were 21.1±1.8 and 20.3±1.9 cm, respectively. Standing and sitting body height were 164.1±8.9 and 88.3±4.3 cm, respectively. Height was significantly correlated with UL_CT, but this relation was not linear (r²=0.064 standing height, 0.062 sitting height). However, LL_CT showed a significant linear correlation with UL_CT (r²=0.485). UL_CT can be estimated indirectly by the following equation: UL_CT=0.823×LL_CT+8.093.

Conclusions

We could measure the ureteral length of healthy Koreans by UL_CT. UL_CT could be estimated indirectly by LL_CT and standing and sitting height. Of these variables, LL_CT provided the most accurate estimate of ureteral length.

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.

Developing a preoperative predictive model for ureteral length for ureteral stent insertion

BACKGROUND

Ureteral stenting has been a fundamental part of various urological procedures. Selecting a ureteral stent of optimal length is important for decreasing the incidence of stent migration and complications. The aim of the present study was to develop and internally validate a model for predicting the ureteral length for ureteral stent insertion.

METHODS

This study included a total of 127 patients whose ureters had previously been assessed by both intravenous urography (IVU) and CT scan. The actual ureteral length was determined by direct measurement using a 5-Fr ureteral catheter. Multiple linear regression analysis with backward selection was used to model the relationship between the factors analyzed and actual ureteral length. Bootstrapping was used to internally validate the predictive model.

RESULTS

Patients all of whom had stone disease included 76 men (59.8%) and 51 women (40.2%), with the median and mean (± SD) ages of 60 and 58.7 (±14.2) years. In these patients, 53 (41.7%) right and 74 (58.3%) left ureters were analyzed. The median and mean (± SD) actual ureteral lengths were 24.0 and 23.3 (±2.0) cm, respectively. Using the bootstrap methods for internal validation, the correlation coefficient (R2) was 0.57 ± 0.07.

CONCLUSION

We have developed a predictive model, for the first time, which predicts ureteral length using the following five preoperative characteristics: age, side, sex, IVU measurement, and CT calculation. This predictive model can be used to reliably predict ureteral length based on clinical and radiological factors and may thus be a useful tool to help determining the optimal length of ureteral stent.

A Randomized Controlled Trial to Compare the Safety and Efficacy of Tadalafil and Tamsulosin in Relieving Double J Stent Related Symptoms

Objectives. To evaluate the safety and efficacy of Tadalafil and Tamsulosin in treating Double J stent related symptoms. Methods. In a prospective study, 161 patients with DJ related symptoms were randomized into 3 groups: Group A patients (54), Group B patients (53), and Group C patients (54). They were given Tadalafil, Tamsulosin, and placebo, respectively, at 1st week till removal of DJ stent at 3rd week. All patients completed Ureteral Stent Symptom Questionnaire (USSQ) at 1st week and at 3rd week. The statistical significant difference among groups was determined by the t-test, Kruskal-Wallis test and multivariate analysis were used to assess association of the variables within the three groups, and the level of significance was set at P < 0.05. Results. Tadalafil and Tamsulosin were comparable in relieving urinary symptoms, general health, and work performance (OR = 0.65, 1.8, and 0.92). But Tadalafil was more effective in relieving body pain, sexual problems, and additional problems than Tamsulosin (OR = 5.95, 19.25, and 2.69) and was statistically significant as P < 0.05. Conclusion. Tadalafil was as effective as Tamsulosin in relieving urinary symptom but more effective in relieving sexual symptoms and body pain.

Verification of relationships between anthropometric variables among ureteral stents recipients and ureteric lengths: a challenge for Vitruvian-da Vinci theory

Objective

To determine and verify how anthropometric variables correlate to ureteric lengths and how well statistical models approximate the actual ureteric lengths.

Materials and methods

In this work, 129 charts of endourological patients (71 females and 58 males) were studied retrospectively. Data were gathered from various research centers from North and South America. Continuous data were studied using descriptive statistics. Anthropometric variables (age, body surface area, body weight, obesity, and stature) were utilized as predictors of ureteric lengths. Linear regressions and correlations were used for studying relationships between the predictors and the outcome variables (ureteric lengths); P-value was set at 0.05. To assess how well statistical models were capable of predicting the actual ureteric lengths, percentages (or ratios of matched to mismatched results) were employed.

Results

The results of the study show that anthropometric variables do not correlate well to ureteric lengths. Statistical models can partially estimate ureteric lengths. Out of the five anthropometric variables studied, three of them: body frame, stature, and weight, each with a P<0.0001, were significant. Two of the variables: age (R²=0.01; P=0.20) and obesity (R²=0.03; P=0.06), were found to be poor estimators of ureteric lengths. None of the predictors reached the expected (match:above:below) ratio of 1:0:0 to qualify as reliable predictors of ureteric lengths.

Conclusion

There is not sufficient evidence to conclude that anthropometric variables can reliably predict ureteric lengths. These variables appear to lack adequate specificity as they failed to reach the expected (match:above:below) ratio of 1:0:0. Consequently, selections of ureteral stents continue to remain a challenge. However, height (R²=0.68) with the (match:above:below) ratio of 3:3:4 appears suited for use as estimator, but on the basis of decision rule. Additional research is recommended for stent improvements and ureteric length determinations.

Pyeloplasty for hydronephrosis: Issues of double J stent versus nephrostomy tube as drainage technique

Aims:

To compare the efficacy, complications, cost analysis and hospital stay between two methods of drainage of the kidney: double J (DJ) stent versus nephrostomy tube following open pyeloplasty for ureteropelvic junction obstruction hydronephrosis.

Patients and Methods:

This was a prospective randomized study of 20 patients in each group over 14 months. Pre and post-operative (3 months) function and drainage were assessed by ethylenedicysteine scan and intravenous urogram.

Results:

Both groups showed similar good improvement in function and drainage. Nephrostomy group had significantly longer hospital stay (P < 0.001) but incurred less cost. Complications with nephrostomy included tube breakage (n = 1) and urine leak after tube removal (n = 2). DJ stents were associated with stent migration (n = 4), increased frequency of micturition (n = 9), dysuria (n = 4) and urinary tract infection (n = 1).

Conclusion:

Both methods of drainage did not interfere with improvement after pyeloplasty. Minor complications were more with DJ stent (P = 0.0003). Although overall cost of treatment was more with stents, they reduced length of hospital stay. Optimal length of stent is essential to reduce complications secondary to migration and bladder irritation.

Which is the best method to estimate the actual ureteral length in patients undergoing ureteral stent placement?

OBJECTIVES

To define the best modality for estimating ureteral length in patients undergoing ureteral stent placement.

METHODS

This study enrolled 151 patients (169 ureters) undergoing stent insertion. In all of them, an intravenous urography and non-contrast computed tomography were carried out. The actual ureteral length was determined by direct measurement using a 5-Fr ureteral catheter. A multivariate analysis evaluated the association between the ureteral length and each of the following parameters: body height, body surface area, ureteral trace by intravenous urography, linear distance (liner distance 1) from the ureteropelvic junction to the ureterovesical junction by intravenous urography, linear distance (liner distance 2) from the mid kidney to the ureterovesical junction by intravenous urography, and the distance from the level of the renal vein to the ureterovesical junction by axial computed tomography (axial computed tomography distance).

RESULTS

The mean actual ureteral length was 23.2 cm (median 24 cm, range 16-29 cm). The Spearman correlation coefficients for body height, body surface area, ureteral trace, liner distance 1, liner distance 2 and axial computed tomography distance were 0.3126, 0.3076, 0.4541, 0.5230, 0.4796 and 0.6168, respectively. Axial computed tomography distance showed the best correlation with the actual ureteral length.

CONCLUSION

The axial computed tomography distance as calculated by the axial computed tomography can more reliably predict the actual ureteral length than other parameters. Further studies are required to show the best method for estimating the actual ureteral length in patients undergoing ureteral stent placement.

Choosing an appropriate length of loop type ureteral stent using direct ureteral length measurement

PURPOSE

The ureteral stent is now a fundamental part of many urological procedures. To decrease ureteral stent-related symptoms, loop type ureteral stent was developed. However the most important factor to decrease urinary symptoms is choosing the optimal length of a ureteral stent. We investigated the relationship between the actual ureteral length and the loop type ureteral stent position.

MATERIALS AND METHODS

A total of 226 loop type polyurethane ureteral stents (156 patients) were inserted with four options for stent length (20, 22, 24 and 26 cm). The ureteral length was measured using a ruled 5-Fr ureteral catheter. The appropriateness of stent position was defined into three groups based on kidney-ureter-bladder films.

RESULTS

Nine stents (3.9%) migrated, 171 stents (75.7%) were in the appropriate position and 46 stents (19.5%) were overlong. The rate of migration rate and overlong stents closely correlated with the ureteral length when the proximal end of the stent was in the renal pelvis.

CONCLUSIONS

It is appropriate to choose a loop type ureteral stent that is the same or 1 cm less than the length of the ureter when the proximal end of the stent will be in the renal pelvis.

Ureteral stent discomfort: Etiology and management

Objectives:

To review the evidence-based literature on the causes, characteristics, and options to manage double J stent-related symptoms.

Methods:

We performed a Medline database assessment on papers that investigated the prevalence, mechanisms, risk factors, bothersome and management of double-J stent-related symptoms. Articles in English were reviewed and summarized.

Results:

Stent-related symptoms have a high prevalence and may affect over 80% of patients. They include irritative voiding symptoms including frequency, urgency, dysuria, incomplete emptying; flank and suprapubic pain; incontinence, and hematuria. Assessment tools are important to determine their intensity and allow for comparisons between different points in the timeline. The Urinary Stent Symptom Questionnaire (USSQ) is the most proper tool used for this purpose. Management should be focused on the prevention and management of symptoms. In this sense, research has focused on new materials and stent designs that would be more compatible to the physiologic properties of the urinary tract and medications that can ameliorate the sensitivity and motor response of the bladder.

Conclusions:

Stent-related symptoms are very common in the Urological clinical setting. It is of major importance for the urologist to understand their physiopathology and to be familiar with ways to avoid or manage them.

Is a 22 cm Ureteric Stent Appropriate for Korean Patients Smaller than 175 cm in Height?

PURPOSE

Determining the ideal length of a ureteric stent is important to avoid complications associated with stent placement. Clinically, most urologists usually choose the length of a ureteric stent according to the patient's height. On the basis of a Chinese population study, a 22 cm ureteric stent has been recommended for patients smaller than 175 cm. We evaluated the appropriateness of this recommendation in Korean patients.

MATERIALS AND METHODS

A total of 70 patients who were smaller than 175 cm and who underwent ureteroscopic lithotripsy and ureteric stent insertion were studied. The appropriateness of the stent length was determined on the basis of plain film findings. Patient discomfort was measured by use of a visual analogue scale (VAS) before the removal of the ureteric stent.

RESULTS

In 29 patients with a 22 cm ureteric stent, 21 patients (72.4%) had an appropriate ureteric stent length and the mean VAS was 4.1. In 36 patients with a 24 cm ureteric stent, 20 patients (55.6%) had an appropriate ureteric stent length and the mean VAS was 4.0. Among 5 patients with a 26 cm ureteric stent, 1 patient (20%) had an appropriate ureteric stent length and the mean VAS was 5.4.

CONCLUSIONS

In Korean patients smaller than 175 cm in height, a 22 cm ureteric stent was an appropriate length.

Endourologic management of malignant ureteral obstruction: indications, results, and quality-of-life issues

Obstruction of the upper urinary tract is a problem commonly faced by practicing urologists. The constant evolution in endourology has effectively facilitated minimally invasive management of upper-tract obstruction. In a case in which malignancy is the cause of obstruction, however, the situation significantly changes. Questions arise regarding the need for relieving the obstruction, the means to accomplish this, and the benefits and drawbacks of each technique regarding both their efficacy and their impact on the patients well-being and the crucial issue of quality of life in the face of malignancy.

Ureteral stent symptoms and associated infections: a biomaterials perspective

Ureteral stents are commonly used in the field of urology, and, given their indwelling nature, are often a nidus for infection and a cause of discomfort. To minimize symptoms, the urologic surgeon should first consider whether a stent needs to be placed at all. Softer stents do not seem to improve patient comfort. Stents that are too long, specifically those that cross the midline of the bladder, significantly increase the frequency of stent-related symptoms. Administering alpha blockers while the stent is indwelling can reduce these symptoms. Antibiotic prophylaxis or concomitant antibiotic administration does not seem to reduce the incidence of stent-related urinary tract infection. At present, drug-eluting stents have shown the most promise for inhibiting bacterial adhesion and biofilm formation. Future stent designs that maintain drainage of the kidney and ureter while minimizing inflammation and contact with the urothelium will improve patient outcomes. By better understanding the basic pathways of bacterial adhesion to biomaterials, new stents and medications that target these mechanisms can be developed to eliminate bacterial adhesion and infection in patients with ureteral stents.

Management of ureteral obstruction due to advanced malignancy: optimizing therapeutic and palliative outcomes

PURPOSE

Treatment of ureteral obstruction due to advanced abdominal or pelvic malignancy is a clinical challenge. We discuss improvements and modern day outcomes in the palliative treatment of patients with ureteral obstruction by antegrade or retrograde ureteral decompression. Also, potential areas of clinical investigation involving ureteral stent improvement and pharmacological management of relief of symptoms resulting from ureteral obstruction are discussed.

MATERIALS AND METHODS

A literature search was performed using the Entrez-PubMed(R) database. All relevant literature on ureteral obstruction, advanced malignancy and nephrostomy, ureteral stent and associated topics concerning palliative care and quality of life were reviewed and analyzed.

RESULTS

Presenting symptoms are varied and depend on the acuity of the underlying problem. Mechanisms underlying the pain and symptoms of extrinsic ureteral compression have not fully been explored but they may include prostaglandin and renin-angiotensin pathways with medical interventions potentially directed at such therapeutic targets. Progressive obstructive uropathy may likely lead to clinical manifestations, such as uremia, electrolyte imbalances and persistent urinary tract infections, if obstruction is not bypassed. New approaches to antegrade and retrograde stenting, and the evaluation of new stent materials may help minimize the complications and side effects of such procedures. Unfortunately the finding of ureteral obstruction due to malignancy carries a poor prognosis with a resulting median survival of 3 to 7 months. This prognosis highlights the importance of maintaining quality of life in these patients.

CONCLUSIONS

Patients presenting with symptoms of ureteral obstruction due to advanced malignancy should be informed of the therapeutic options in the context of the poor prognosis. In the meantime research is needed to find methods of urinary diversion and pharmacological intervention for symptomatic relief without compromising quality of life in patients at the end of life.