Abstract
Objective
To investigate the impact of preoperative double J (DJ) stent insertion on outcomes of retrograde semi-rigid ureteroscopy (URS) in patients with upper small and medium sized ureteral stones.
Methods
Between April 2018 and September 2019, we retrospectively reviewed the medical register of Hillel Yaffe tertiary reference Centre (HYMC) for patients who had undergone retrograde semi-rigid URS for urolithiasis. Patients were separated into two groups depending on whether they accepted the DJ stent placement before URS (Group A) or not (Group B). Operating time, stone clearance rate, number of ‘rescue’ DJ stents, duration of ‘rescue’ stents, complication rate and requirement for repeat URS were compared between groups.
Results
318 procedures undertaken in 290 patients were included (Group A, 83 procedures in 80 patiants; Group B, 235 procedures in 210 patients). By comparison with the non-stented group, patients in the preoperative DJ stented group had a higher stone clearance rate, lower complication rate, less need for postoperative ‘rescue’ DJ stent, lower duration of ‘rescue’ stent and lower re-operative URS requirement, including application of a flexible URS.
Conclusion
Facilitated semi-rigid URS with upstream DJ stenting for small and medium size ureteral stones has favourable periprocedural outcomes compared with primary URS.
Introduction
Urolithiasis is the a common pathology encountered in urology practice. 1 It has high morbidity and socio-economic impact, and despite being perceived as a non-life-threatening condition, its related mortality rate is considerable.1, 2 The reported lifetime risk for urolithiasis is estimated to range from 5–12% in western countries, afflicting 13% of men and 7% of women in the population.1, 3 Epidemiological studies have estimated the prevalence of urolithiasis to be approximately 12% worldwide,4,5 with approximately 1 out of 11 people in the USA affected. In addition, the disease varies across ethnic backgrounds.6,7
The choice of treatment for a ureteral stone depends on its size, location and the severity of pain it causes. Asymptomatic and small stones can be managed conservatively with analgesics and anti-emetic medications for four to six weeks and there is no need for surgical removal. 8 Stones that are associated with an obstruction, uncontrolled pain, renal failure, and multiple infections require surgical intervention in the mode of stenting, nephrostomy, or ureteroscopy (URS).8,9
Since its first introduction in 1967, the ureteric JJ stent, also known as double J (DJ) stent has become one of the most widely used tools in urology. 10 The stent is used to provide drainage from the upper urinary tract when obstruction of the ureter is present or anticipated. The stent is placed so that its upper end is in the kidney and its lower end is in the urinary bladder. Ureteral stenting is widely used as a complementary tool for drainage either before or after endoscopic procedures in the upper urinary tract system.10–13 The indwelling stent may remain in the patient for some time. Studies have reported the effectiveness of DJ stent in treating ureteral stones, when primary ureteroscopic attempts to access the ureter have failed. 14 Nevertheless, indwelling stents are notoriously fraught with patient discomfort, and their colonization by a host of microorganisms may discourage their preoperative insertion. 15
The aim of this present study was to investigate the impact of preoperative DJ stent insertion on outcomes of retrograde semi-rigid URS in patients with upper small and medium sized ureteral stones.
Methods
Between April 2018 and September 2019, we retrospectively reviewed the medical register of Hillel Yaffe tertiary reference Centre (HYMC) for patients who had undergone retrograde semi-rigid URS for urolithiasis. Only patients who were offered a DJ stent placement were included. Eligible patients were those who had been admitted for small or medium sized ureteral stones. Patients with renal stones, high volume stones (i.e., >12 mm), multiple ureteral stones (i.e., >2 stones), bilateral stones, previously documented ureteral stones, a previous urological intervention, a previous negative URS, signs or symptoms of pregnancy, receiving anticholinergic medication or aged less than 18 years, were excluded from the study. The study followed the STROBE statement guidelines 16 and was approved by the Hillel Yaffe ethical committee (IRB No. 0071-20HYMC). Written/verbal consent was not required because it was a retrospective study and patient data were anonymized prior to analysis.
Patients were separated into two groups depending on whether they accepted the DJ stent placement before URS (Group A) or not (Group B). The patients’ characteristics (i.e., age, sex, body mass index [BMI], ethnicity) were recorded. In addition, for each stent procedure, stone features [i.e., size, location, density and laterality], operating time, complications, stone clearance rate, need for postoperative DJ stenting and number of repeat URS procedures were recorded.
All patients had a diagnostic, non-contrast computed tomography (CT) scan to confirm diagnosis and specify the characteristics of each ureteric stone. Groups A and B were subdivided into four subsets according to the size and location of the stone in the ureter: (1), >5 mm in the middle and upper ureter; (2), >5 mm in lower ureter; (3), ≤5mm in middle and upper ureter; (4), ≤5 mm in lower ureter.
All the ureteroscopic procedures were performed under general anaesthesia by urologists with established sub-specialty in stone surgery initially using a 6.5/8-Fr semi-rigid ureteroscope (Storz). A Storz Flex X2 flexible ureterorenoscope (Karl Storz Endoscopy) was available as a rescue tool. Ureteral pigtail DJ stents were placed in the same diameter (6 FR) and were preoperatively inserted in the operating room using cystoscopy under local/general anaesthesia. Laser fibres were used for stone fragmentation (Lumenis, Inc.) and all stone fragments were retrieved using tipless 1.7-Fr Cook NGage® nitinol basket (Cook Medical, Bloomington, IN, USA). The objective of the ureteroscopic procedures was to clear all retrievable residual kidney stone fragments >2 mm. At the end of each procedure the choice for implantation of a postoperative drainage tube (i.e., DJ stent, DJ stent with external wire or ureteral catheter) was left to the surgeon’s discretion. The decision for postoperative ureteral catheterization relied on several technical intraoperative factors that included: operating time; difficult stone fragmentation or retrieval; ureteral wall trauma; ureteral orifice status; the surgeon’s assessment of ureteral diameter and clearance (including oedema and stricture).
According to our local practice, each patient was followed-up for three to six weeks post-procedure at our stone clinic. Patients underwent postoperative imaging (i.e., non-contrast CT scan, plain X-ray, kidney, ureter, bladder X-ray for radio-opaque stones or urinary ultrasound), and had blood tests to assess their stone-free status. By comparison with data from the non-stented URS group, the efficacy of preoperative DJ stenting was evaluated in terms of, operating time, stone clearance rate, number of postoperative ‘rescue’ DJ stenting procedures, duration of ‘rescue’ stents, complication rate and requirement for repeat URS.
Statistical analyses
Statistical analysis was performed using SPSS software (version 28 for Windows®; SPSS Inc., IBM Corp, Armonk, NY, USA). A P-value <0.05 was considered to indicate statistical significance. Quantitative data were expressed as mean, mean ± standard deviation (SD), median (range), or number and percentage. Independent t-test was used for normally distributed variables and frequency data were compared using χ2 test. Multinomial logistic regression was used to model effects of age, sex, BMI, and ethnicity on the two groups.
Results
Of the 475 ureteroscopic procedures screened, 318 procedures undertaken in 290 patients were suitable for the study. Group A (stented) included 83 procedures undertaken in 80 patients and the subsets according to stent procedures were n = 37, n = 15, n = 11, n = 20 for Subsets, 1, 2, 3 and 4, respectively (Table 1). Group B (non-stented) included 235 procedures undertaken for 210 patients and the subsets according to stent procedures were n = 66, n = 43, n = 49, n = 77 for Subsets, 1, 2, 3 and 4, respectively. The median time from DJ stenting to URS was 13 (9–17) days and the median time from initial admission to the elective URS was 15 (12–18) days. The prevalence of proximal ureteral stones was 42% (35/83) and 35% (82/235) in the stented and non-stented groups, respectively. The prevalence of middle ureteral stones was 16% (13/83) and 14% (33/235) in the stented and non-stented groups, respectively. The prevalence of distal ureteral stones was 42% (35/83) and 51% (120/235) in the stented and non-stented groups, respectively (Table 1).
Procedural characteristics.
Data are expressed as, mean ± standard deviation, n, or n (%).
*P, proximal; M, middle, D, distal; URS, ureteroscopy.
αGroups A and B were subdivided into four subsets according to the size and location of the stone in the ureter: (1), >5 mm in the middle and upper ureter; (2), >5 mm in lower ureter; (3), ≤5 mm in middle and upper ureter; (4), ≤5 mm in lower ureter.
While there were no differences between groups in stone location or operating time, significantly larger stones were observed in the DJ stented group compared with the non-stented group (6.5 ± 2.3 mm vs. 5.7 ± 2.2 mm; P = 0.006) (Table 1 and Figure 1a). Preoperative stenting resulted in a significantly lower need for ‘rescue’ DJ stenting at the end of URS (28% vs. 54%, respectively, P < 0.001 (Table 1). Moreover, for patients who required a postoperative DJ stent, the mean duration of catheterisation was significantly shorter in the stented group compared with the non-stented group (12 vs. 16 days, P = 0.001) (Table 1 and Figure 1b). In addition, the requirement for repeat URS was significantly greater in the non-stented group compared with the stented group (8% vs. 2%, P = 0.033 (Table 1). Moreover, none of the patients in the stented group required flexible URS treatment, compared with three patients in the non-stented group. While not attaining statistical significance, there was a positive trend in the DJ stented group for a lower complication rate (5% vs. 11%) and a greater stone clearance rate (95% vs. 89%) compared with the stented group (Table 1).
(a) Stone diameter. Significantly larger stones were observed in the double J (DJ) stented group compared with the non-stented group (6.5 ± 2.3 mm vs. 5.7 ± 2.2 mm; P = 0.00589). (b) Mean duration of postoperative stent (days). For patients who required a postoperative double J (DJ) stent, the mean duration of catheterisation was significantly shorter in the stented group compared with the non-stented group (Group A, 12 days; Group B, 16 days; P = 0.00106).
Accounting for confounding variables, we assessed the effect of age, sex, BMI, and ethnicity using multinomial logistic regression and found that there were no differences between the two groups (Table 2). Comparing stone characteristics, we found significant differences between groups in stone diameter (P = 0.005) and stone density (P = 0.008). with greater values in the stented group compared with the non-stented group (Table 2). There was no difference between groups in other stone characteristics, (i.e., laterality, stone location and the number of stones).
Patients’ and Stone characteristics.
Data are expressed as mean ± standard deviation, or n (%).
*number of procedures
HU, Hounsfield units.
Discussion
In this retrospective study, we found favourable outcomes of URS following preoperative DJ stent insertion. The stented group represented a ‘facilitated URS’ model in which the decongestive effect of stenting probably enhanced the procedure. By comparison with the non-stented group, patients in the preoperative DJ stented group had a higher stone clearance rate, lower complication rate, less need for a rescue DJ stent and lower re-operative URS requirement, including application of a flexible URS. While there was no difference between groups in terms of stone location and the number of stones, the stented group had larger and more dense stones than the non-stented group.
The prevalence of proximal ureteral stones in our study was 42% and 35% in the pre-stented and non-stented URS groups, respectively. The challenging occurrence of retrograde ureteric calculi migration was described in a previous study that used nephrostomy guided antegrade irrigation to optimize semirigid URS for upper ureteral stones and found a positive outcome in terms of stone clearance and total operation time compared with conventional retrograde URS. 17 However, a prospective study involving 367 patients found no significant differences between deferred URS following initial ureteric stenting and primary URS for ureteral calculi. 18 While the results of our study are in agreement with the findings of a meta-analysis that showed preoperative stenting improves ureteral stone clearance rates and complications after flexible URS, 19 they are in contrast with other studies that have found pre-stenting does not show any benefit for ureteral stones or stones treated by semirigid ureteroscopy.20,21 However, we believe that the mechanical anti-congestive effect of preoperative DJ stent placement, enhances the microenvironment activity of ureteral stones, reduces the attachment of the stones to the lining cells, and makes it easier to remove the blocking stone.
The study had several limitations. For example, it was retrospective and data were obtained from electronic medical records and so results may have been influenced by interpretation biases. In addition, most patients were male which may have limited the generalizability of the results across both sexes. Therefore, further prospective, controlled studies are required to confirm our findings. Nevertheless, we showed that facilitated semi-rigid URS with upstream DJ stenting for small and medium size ureteral stones has favourable periprocedural outcomes compared with primary URS.
Research Data
sj-pdf-1-imr-10.1177_03000605231152088 - Research Data for Facilitated ureteroscopy using DJ stent implantation in ureterolithiasis: A retrospective study
Research Data, sj-pdf-1-imr-10.1177_03000605231152088 for Facilitated ureteroscopy using DJ stent implantation in ureterolithiasis: A retrospective study by Ghalib Lidawi, Rami Abu Fanne, Muhammad Majdoub, Mohsin Asali, Abdel-Rauf Zeina and Ronen Rub in Journal of International Medical Research
Research Data
sj-pdf-2-imr-10.1177_03000605231152088 - Research Data for Facilitated ureteroscopy using DJ stent implantation in ureterolithiasis: A retrospective study
Research Data, sj-pdf-2-imr-10.1177_03000605231152088 for Facilitated ureteroscopy using DJ stent implantation in ureterolithiasis: A retrospective study by Ghalib Lidawi, Rami Abu Fanne, Muhammad Majdoub, Mohsin Asali, Abdel-Rauf Zeina and Ronen Rub in Journal of International Medical Research
Footnotes
References
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