The efficacy and safety of string stents after retrograde intrarenal surgery for urolithiasis

INTRODUCTION: Ureteral stent insertion is frequently chosen after upper tract endourological procedures. The use of stents carrying a suture string is sometimes used to facilitate the extraction of the stent. In this systematic review and meta-analysis, we aimed to provide stronger evidence for the efficacy of string stems, by comparing them to non-string stcnts, in matters of patients' quality of life (QoL), stent-related symptoms (SRS) and complications. EVIDENCE ACQUISITION: A systematic review was conducted on PubMed, SCOPUS, Cochrane. EMBASE and Web of Science. The studies included were only comparative randomized controlled trials which included at least one group with tethered ureteral stent and one group with standard stent after the performance of endoscopic surgery for lithiasis of upper urinary tract. Primary endpoints were QoL expressed as general health, urinary symptoms as well as impact on work performance and SRS, expressed by VAS score. Secondary endpoints included complications such as stent migration, stent dislodgement, urinary tract infections (UTIs), emergency room visits and retained stent. EVIDENCE SYNTIIESIS: We identified nine studies to be included in the qualitative synthesis and 3 randomized controlled trials to be included in the quantitative synthesis and the meta-analysis. The statistical difference in the stent related QoL was insignificant. General health was less affected in the non-string group. The urinary symptoms and the impact on work performance were similar between the groups. VAS pain score during, the time that the patients were stented was insignificantly less in the non-string group, while VAS pain score was higher in the non-string group at extraction. Stent dislodgement was more frequent in the string group. There was no difference between the groups concerning the rate of UTIs. CONCLUSIONS: Non-string stents affected less the patients' QoL, in terms of general health and urinary symptoms, caused less stent related pain in cases of stent in situ and caused stent dislodgment in fewer patients. On the contrary, string stents caused less pain at extraction. All the aforementioned differences did not reach statistical difference.