Percutaneous Antegrade Double J Ureteral Stent Placement at Kenyatta National Hospital: Indications, Technical Success Rate, Commonly Encountered Problems and Solutions

Abstract

Background: Percutaneous ureteric stenting using image guidance is a safe method in treating obstructive ureteral pathology. This technique has showed higher technical success rates compared to the retrograde cystoscopic trans-vesicle approach in treatment of malignant ureteral obstruction. However, it is less well known and is usually requested after failure of retrograde ureteral stent placement by endo-urologists. Unlike the retrograde stenting, antegrade stenting does not require the use of either general or spinal anaesthesia. Due to development of nephrostomy services in many hospitals, antegrade stenting has become a common procedure in the radiology department. Despite improvement in the stent designs, percutaneous stent placement is challenging especially in cases of grossly dilated ureters and tight ureteral strictures. Objective: This study sought to identify the indications, determine the technical success rate and identify the commonly encountered problems and their solutions during percutaneous antegrade double J ureteral stenting at a national referral institution. Materials and Methods: Data of 53 patients who underwent 55 antegrade stenting procedures in the interventional radiology suite of Kenyatta National hospital between 1st June 2020 to 30th June 2022 was retrieved and retrospectively analyzed. Patient related variables included age and sex. Lesion related variables included causes of obstruction, laterality and site of obstruction. Technique related variables included site of calyceal access, severity of ureterohydronephrosis and shape of the ureters. Data on techniques modifications used to overcome the difficulties encountered like use of balloons to dilate a tight stricture and use of an introducer sheath to facilitate stent delivery was collected. Data of different indications for antegrade stenting was collected and analyzed using frequency statistics. Univariate analysis involved calculation of the measures of central tendency and dispersion which include: means, medians, standard deviations for continuous variables. For categorical variables, frequency distributions were determined and results presented using frequency tables and appropriate charts. Bivariate analysis was used to investigate any association between successful deployment of the stent and lesion related variables as well as stenting success and technique related variables. Relationships exhibiting P values of less than 0.05 were reported as statistically significant. Results: A total of 55 procedures were done. Of these, seven procedures were performed in 7 patients with benign strictures while 48 procedures were done in 46 patients with malignant strictures. Among the malignant causes of ureteral obstruction, carcinoma of the cervix was the most common accounting for 79.17% of the procedures. Other malignant causes included prostate cancer (9%), bladder cancer (6%), retroperitoneal carcinoma (2%), endometrial cancer

(2%) and colon cancer (2%). Benign causes of ureteral strictures included post-surgical complications (42.85%, idiopathic (42.5%) and urolithiasis (14.29%). There was high overall technical success rate of 90.91%. Technical success rate for malignant strictures was 91.6% and 85.71% for benign strictures. Majority of stenting failures occurred in malignant strictures (80%) and were caused by cancer of the cervix. The four procedures performed after failed retrograde stenting were all successful when subjected to antegrade stenting. Common problems encountered during antegrade stenting included dilated and tortuous ureters, (47.42%), suboptimal calyceal access (20.62%), tight obstruction (18.56%) and difficulty in positioning the proximal pigtail loop of the ureteric stent (13.40%). Dilated and tortuous ureters were first decompressed by placement of nephrostomy tubes before antegrade stenting. Suboptimal calyceal access was overcome by use of a vascular sheath, stiff guidewire and change of calyceal access to a mid-pole calyx where necessary. For tight obstructions, use of a hydrophilic guide wire and vascular catheters were used to cross the lesion. Super stiff guide wire was used to facilitate the passage of the stent through the lesion. Balloon dilatation of a tight stricture was done to allow easy passage of the stent. Conclusion: The study showed that the most common indication for antegrade ureteral stenting at KNH was malignant obstruction largely from carcinoma of the cervix. Antegrade stenting has high technical success rate for both benign and malignant ureteral obstruction. Among the commonly encountered problems, grossly dilated and tortuous ureters with Z and pigtail ureteric shapes were more challenging to stent. Though challenges are encountered during antegrade ureteric stenting, they can be overcome by various technique modifications.