Use of Self-Expanding Metallic Ureteral Stents in the Secondary Treatment of Ureteral Stenosis Following Kidney Transplantation

A new technique for the treatment of ureteric stricture after kidney transplantation

OBJECTIVE

To evaluate the safety and effectiveness of endoscopic treatments with Allium® metal ureteric stent (AMUS) for ureteric strictures after kidney transplantation (KT).

PATIENTS AND METHODS

In a prospective manner, we gathered clinical data from 68 patients who underwent endoscopic treatments with AMUS for ureteric strictures after KT between January 2019 and March 2022. The definition of surgical success was the unobstructed drainage of the AMUS, or in cases where there was AMUS migration, occlusion or encrustation and subsequently removed, there is no worsening of renal hydronephrosis in the patient during the follow-up period.

RESULTS

Based on the specific circumstances of the ureteric strictures, three distinct types of surgery were selected for treatment. The overall success rate of endoscopic treatments for ureteric strictures following KT was 90% (61/68) during a follow-up period of 1 year. Surgical complications included haematuria (18%), pain (10%), urinary tract infections (7.4%), and lower urinary tract symptoms (7.4%). The incidences of stent migration, occlusion, and encrustation were 10%, 2.9%, and 1.5%, respectively. Postoperatively, significant improvements were observed in various parameters. At 1 month after surgery, there was a notable decrease in blood creatinine levels (105.5 vs 90.4 mol/L), urea nitrogen levels (6.6 vs 5.4 mmol/L), and hydronephrosis volume (64.4 vs 43.9 mL). Additionally, the serum estimated glomerular filtration rate increased from 49.5 to 64.4 mL/min/1.73 m2. The follow-up results of patients at 1 year after surgery were similar to those observed at 1 month after surgery.

CONCLUSIONS

Systemic endoscopic treatments with AMUS were found to be safe and effective for ureteric strictures after KT with short-term follow-ups. This technique offers a novel option for the treatment of post-KT strictures.

Effectiveness of endourological management of ureteral stenosis in kidney transplant patients: EAU-YAU kidney transplantation working group collaboration

PURPOSE

Ureteral stenosis (US) in kidney transplant (KT) recipients is associated with poorer long-term graft survival. Surgical repair is the standard of care, and endoscopic treatment represents an alternative for stenosis < 3 cm. We aimed to determine the effectiveness and safety of endourological management of US in KT patients and predictors of failure.

METHODS

A retrospective multicenter study was conducted in four European referral centers, including all KT patients with US managed endoscopically between 2009 and 2021. Clinical success was defined as the absence of upper urinary tract catheterization, surgical repair or transplantectomy during follow-up.

RESULTS

A total of 44 patients were included. The median time to US onset was 3.5 months (IQR 1.9-10.8), the median length of stricture was 10 mm (IQR 7-20). Management of US involved balloon dilation and laser incision in 34 (79.1%) and 6 (13.9%) cases, respectively, while 2 (4.7%) received both. Clavien-Dindo complications were infrequent (10%); only one Clavien ≥ III complication was reported. Clinical success was 61% at last follow-up visit (median = 44.6 months). In the bivariate analysis, duckbill-shaped stenosis (vs. flat/concave) was associated with treatment success (RR = 0.39, p = 0.04, 95% CI 0.12-0.76), while late-onset stenosis (> 3 months post KT) with treatment failure (RR = 2.00, p = 0.02, 95% CI 1.01-3.95).

CONCLUSIONS

Considering the acceptable long-term results and the safety of these procedures, we believe that the endoscopic treatment should be offered as a first-line therapy for selected KT patients with US. Those with a short and duckbill-shaped stenosis diagnosed within 3 months of KT seem to be the best candidates.

Effect of Nanobubble-Based Ultrasound Imaging Technology on the Treatment of Ureteral Stenosis

In order to explore the effect of nanobubble-based ultrasound imaging technology on the treatment of ureteral stenosis, a total of 120 patients, who were confirmed as ureteral stenosis by surgery, pathology or multiple imaging examinations at a designated hospital of the study from December 2015 to December 2018, were selected as research objects and were divided into three groups of targeted nanobubble (TN) group, blank nanobubble (BN) group and control (CT) group with 40 cases in each group. The TN group utilized the nanobubbles with a particle size of (499.52±72.87) nm as carriers to compare and analyze patients' ultrasound images for the predisposition and etiology of ureteral stenosis and the sonogram variations of hydronephrosis, renal pelvis; the BN group utilized the blank nanobubble with a particle size of (446.71±45.36) nm as carriers to perform ultrasound imaging and diagnostic analysis of ureteral stenosis; the CT group directly conducted ureteral stenosis treatment with ultrasound imaging technology. The results showed that the total coincidence rates of the targeted diagnosis for ureteral stenosis of the TN, BN and CT group were 94.38%, 87.52%, and 67.94%, respectively; the coincidence rates of different examination methods for different diagnostic parts were different and the diagnostic coincidence rates of TN group for pelvic ureteral transition area, end of ureter, and the area between pelvic ureteral transition area and end of ureter were 82.91%, 79.66%, and 75.17%, respectively; the diagnostic coincidence rates of BN group for those were 80.32%, 94.77%, respectively and 92.18% and the CT group were 58.66%, 72.14%, and 66.48%, respectively; the diagnosis coincidence rates for ureteral stenosis etiology of the TN, BN and CT group were 93.81%, 82.66% and 64.57%, respectively. Therefore, it was believed that the nanobubble-based ultrasound examination can accurately diagnose the site of ureteral stenosis through the exploration of hydronephrosis and ureteral dilatation with the advantages of simplicity, no pain, repeatable examination, and no impact on renal function, and having high clinical value for diagnosing ureteral stenosis.

Update on the Management of Urological Problems Following Kidney Transplantation

Urological problems in kidney transplant recipients are not limited only to posttransplantation urological complications. These problems are a cause of significant patient mortality and morbidity that have wide-ranging effects on graft survival throughout the entire life of the graft. Ultimately, the transplant comprises a major portion of the urinary system; therefore, the transplant team should be prepared for foreseeable and unforeseeable urological problems in the short and long terms. These mainly include postoperative urological complications (urine leakage, ureteral stenosis, and vesicoureteral reflux), bladder outlet obstruction, and graft urolithiasis. In recent years, significant advances have been made in the management of urological complications, especially due to advances in endourologic interventions. The aim of this review is to summarize the management of urological problems after kidney transplantation in the context of the current literature.

Temporary Covered Metallic Ureteral Stent Placement for Ureteral Strictures following Kidney Transplantation: Experience in 8 Patients

This brief report presents 8 patients with silicone-covered metallic stent placement for ureteral strictures refractory to double-J stent placement, following kidney transplantation. Stent removal was successfully performed in 7 patients via antegrade (n = 4) or retrograde (n = 3) access 6 weeks to 6 months after stenting for elective removal (6-month interval, n = 3), urothelial hyperplasia (n = 2), or stent migration (n = 2), and their mean primary ureteral patency after stent removal was 15.4 months (range, 2-27 months). Hematuria (n = 2) and pain (n = 3) occurred, but resolved within 1 week. One stent was removed during reconstructive surgery. During follow-up of mean 22.6 months after stent removal, ureteral strictures recurred in 2 patients.

[Imaging features of hip joint in patients with ankylosing spondylitis undergoing total hip arthroplasty]

Objective

To study the imaging features of the hip joint by measuring the imaging parameters of spine, pelvis, and hip joint before and after total hip arthroplasty (THA) in patients with ankylosing spondylitis (AS) undergoing THA so as to provide reference for selection of operation methods and prosthesis.

Methods

Between January and July 2015, 38 patients (56 hips) with AS underwent primary THA as AS group, and 36 patients (45 hips) with osteonecrosis of the femoral head underwent THA as control group. There was no significant difference in side ( χ2=1.14, P=0.95). The acetabular abduction angle (ABA), acetabular anteversion angle (AVA), center collum diaphyseal (CCD), offset, height from rotation center to lesser trochanter (HRCLT), femoral intertrochanteric distance (FID) were measured by CT three-dimensional morphology. The canal flare index (CFI), cortical thickness index (CTI), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) were measured by X-ray film before operation. The AVA, ABA, and the filling ratio were measured on the postoperative X-ray film.

Results

There was no significant difference in preoperative AVA and ABA and postoperative ABA between 2 groups ( P>0.05), but significant difference was found in postoperative AVA ( t=6.71, P=0.00). The mean PI, SS, and PT in AS group were 48.37° (range, 41-58°), 5.64°(range, 2-11°), and 12.85° (range, 5-26°), respectively. There was significant difference in CCD, CFI, and CTI between 2 groups ( t=3.63, P=0.04; t=5.12, P=0.02; t=3.91, P=0.04), but offset, HRCLT, and FID all showed no significant difference ( t=0.41, P=0.36; t=0.33, P=0.56; t=0.59, P=0.12). On the basis of the Noble classification, medullary cavity of the femur was rated as chimney type, ordinary type, and champagne flute type in 32, 18, and 6 hips of AS group, and in 4, 28, and 13 hips of control group respectively. Filling ratio of distal segment in AS group was significantly lower than that in control group ( t=5.64, P=0.02), but there was no significant difference in the filling ratio of middle and proximal segments between 2 groups ( t=0.29, P=0.61; t=0.55, P=0.13).

Conclusion

Compared with patients having osteonecrosis of the femeral head, there is no significant difference in preoperative AVA and ABA, but postoperative AVA significantly increase in patients with AS. Because AS patients have mainly chimney type medullary cavity of the femur, the filling ratio of middle and distal segment is lower when tapered stems are used, and the filling ratio of anatomic stems is higher.