Impact of Vacuum-Assisted Mini-Endoscopic Combined Intrarenal Surgery for Staghorn Stones: Analysis of Perioperative Factors of Postoperative Fever and Stone-Free Status.

Background and Objective: This retrospective cohort study aimed to evaluate the clinical outcomes of vacuum-assisted mini-endoscopic combined intrarenal surgery (vmECIRS) for staghorn stones. Patients and Methods: We analyzed a total of 61 cases treated with initial vmECIRS using 14F/16F ClearPetra® percutaneous sheaths for staghorn stones. We primarily measured complications and stone-free rates (SFRs) to evaluate the safety and efficiency of vmECIRS. In addition, pre- and intraoperative factors in patients who experienced postoperative fever >38°C and achieved an initial stone-free status were evaluated. Results: The percentages of staghorn stones were 36.1% and 63.9% for complete and partial stones, respectively. The median stone volume was 8.48 cm3. The median operation time was 117 minutes, and the mean number of procedures was 1.54. Regarding postoperative complications, postoperative fever >38°C was reported in 18 patients (29.5%). The initial and final SFRs were 50.8% and 91.8%, respectively. Among patients with emerging fever >38°C, positive urine culture was the only significant risk factor in the multivariate analysis (odds ratio [OR], 7.500; 95% confidence interval [CI], 1.772-31.751; p = 0.006). Moreover, for achieving initial stone-free status, body mass index and stone volume were significant risk factors in the multivariate analysis (OR, 0.872; 95% CI, 0.776-0.980; p = 0.021; and OR, 0.882; 95% CI, 0.784-0.994; p = 0.039, respectively). Conclusions: These findings suggest that vmECIRS is safe and effective for treatment of staghorn stones. Although current guidelines suggest that percutaneous nephrolithotomy is the gold standard surgical technique for staghorn stones, vmECIRS could also be a treatment strategy. The Clinical Trial Registration number (ID: 2022-05-17-1).

Pelvicalyceal anatomy on the accessibility of reusable flexible ureteroscopy to lower pole calyx during retrograde intrarenal surgery.

OBJECTIVE: This study aimed to evaluate the pelvicalyceal anatomy on accessibility of reusable flexible ureteroscopy (fURS) to the lower pole calyx during retrograde intrarenal surgery (RIRS). METHODS: Here, 854 patients with ureteral or kidney stones with access to a renal collecting system using reusable fURS were classified into either the accessible group, in whom the deepest lower pole calyces could be touched; and the inaccessible group, in whom the deepest lower calyces could not be touched. We measured the infundibulopelvic angle (IPA), infundibular width (IW), infundibular length (IL), and calyceal pelvic height (CPH) using retrograde pyelograms and performed intergroup comparisons. RESULTS: The median IPA, IW, IL, and CPH in the accessible and inaccessible group were 60.5° and 45.6° (p < 0.001), 10.8 and 9.4 mm (p < 0.001), 33.2 and 36.4 mm (p < 0.001), and 25.9 and 30.9 mm (p < 0.001), respectively. IPA (OR 0.963, 95% CI 0.952-0.974, p < 0.001) and IW (OR 0.519, 95% CI 0.331-0.816, p = 0.004) were significant risk factors of renal pelvicalyceal anatomy related to the accessibility of the lower pole calyces. The cut-off value for IPA and IW was 45.8°(p < 0.001) and 7.8 mm (p < 0.001), respectively. CONCLUSIONS: IPA < 45.8° and IW <7.8 mm were negative predictors to access the lower pole calyces when using reusable fURS during RIRS.

Primary impact of simultaneous use of double devices through one-working channel when performing flexible ureteroscope with ureteral access sheath for single ureteral stone: In bench and retrospective clinical study.

OBJECTIVES: This study aimed to compare the simultaneous use of two devices versus a single device through a single working channel in flexible ureteroscopy using a ureteral access sheath for single ureteral stones. METHODS: In a bench study, the time to (i) set laser fiber, (ii) exchange laser fiber and nitinol basket through working channel, and (iii) pull out the device from working channel were measured 10 times in each step. In a clinical study, 156 patients who underwent flexible ureteroscopy with a ureteral access sheath for a ureteral stone in middle and upper ureter between April 2019 and November 2021 were assessed. One device was used at a time for 79 patients (S-Group) and two were simultaneously used for 77 (D-Group). Surgical outcomes and complications were compared. RESULTS: In the bench study, the mean time to change from laser fiber to basket and from basket to laser fiber through the working channel were 26.1 ± 3.7 s and 23.6 ± 2.0 s (p = 0.084), respectively, which were significantly longer than the laser setup time (p < 0.001). In the clinical study, although the stone-free rate was not significantly different between the groups (S-Group 89.8%, D-Group 93.5%; p = 0.412), the median operation time was significantly shorter (p < 0.001) and the rate of postoperative stenting was significantly lower (p = 0.002) in the D-Group. There were no significant between-group differences in intra- and post-operative complications. CONCLUSION: The simultaneous use of two devices through a single working channel is safe and could help save the time needed to exchange the laser fiber and nitinol basket.

The lumbosacral angle is a significant predictor for using a semi-rigid ureteroscopic approach in middle ureteral stones.

Background: Ureteroscopy for middle ureteral stones is often difficult from an anatomical view. This study aimed to evaluate the pelvic anatomy in three dimensions and investigate the relationship between the pelvic anatomy and potential semi-rigid ureteroscopic approach for treating middle ureteral stones. Methods: From a total of 967 patients who underwent ureteroscopy from December 2017 to January 2021, 124 patients who had middle ureteral stones were included in this retrospective cohort study. The pelvic transverse diameter, pelvic vertical diameter, pelvic depth, and lumbosacral angle were measured through preoperative non-contrast computed tomography to define the shape of the pelvic cavity. The relationship between the reachability of the middle ureteral stone using a semi-rigid ureteroscope and the aforementioned anatomical factors, as well as treatment outcomes, was examined retrospectively. Results: The lumbosacral angle and female sex were significant predictors of the possibility of a semi-rigid ureteroscopic approach to middle ureteral stones [odds ratio =1.08; 95% confidence interval (CI): 1.03-1.14; P=0.003, and odds ratio =3.23; 95% CI: 1.12-9.32; P=0.03, respectively]. The cutoff value of the lumbosacral angle was 149.9°, with a sensitivity of 55.1% and a specificity of 72.7%. The time to reach the stone was longer in the lumbosacral angle <150° group than in the lumbosacral angle ≥150° group (P=0.049). Conclusions: In this study, gradual lumbosacral angle and female sex are positive predictors of the reachability of the middle ureteral stone with a semi-rigid ureteroscope.

Evaluating Predictive Factor of Systemic Inflammatory Response Syndrome and Postoperative Pain in Patients Without Ureteral Stent Placement After Ureteral Access Sheath Use in Flexible Ureteroscopy for Stone Management.

Background and Objective: This retrospective cohort study aimed to evaluate the safety of stentless flexible ureteroscopy (fURS) using a ureteral access sheath (UAS) for stone management. Patients and Methods: A total of 270 ureteral stentless postoperative patients were analyzed. Stentless indication was characterized by having no ureteral wall or mucosa injury with only slight erosion, <1 hour operative time, and no endoscopic stone fragments with or without stone dust. Postoperative complications and pain were analyzed for safety measurements. In addition, preoperative and intraoperative risk factors associated with the incidence of systemic inflammatory response syndrome (SIRS) and postoperative pain were evaluated. Results: The most common UAS sizes were 10/12F (69.6%) and 9.5/11.5F (28.1%). The rate of patients who were stone free was 95.9%. The median operation time was 34 minutes. Only three grade 1 ureteral injuries occurred intraoperatively. Postoperative SIRS occurred in 8.8% of patients, and postoperative use of analgesics was 35.9%. Only four patients were required to undergo eventual ureteral stenting. Less than 10/12F UAS was the only factor positively associated with preventing postoperative SIRS (odds ratio [OR], 4.733; 95% confidence interval [CI], 1.085-20.644). Older age and preoperative ureteral stenting were positively associated with preventing postoperative pain (OR, 0.970; 95% CI, 0.951-0.990 and OR, 0.427; 95% CI, 0.232-0.786; respectively). Conclusion: Stentless fURS with UAS in stone management was feasible for selected patients. UAS size of <10/12F, older age, and preoperative stenting are possible keystones to achieving stentless fURS with UAS postoperatively. IRB approval number; 20216101.

Single-Session Impact of High-Power Laser with Moses Technology for Lower Pole Stones in Retrograde Intrarenal Surgery: Retrospective Study.

Background: This study aimed to evaluate the efficacy of a high-power holmium laser with Moses technology (MT) for the treatment of lower pole stones during retrograde intrarenal surgery (RIRS). Methods: Herein, 305 patients with lower pole stones who underwent RIRS using a high-power holmium laser with MT were retrospectively classified into the stone-free (SF) and non-SF groups. We measured the stone burden, stone volume, stone hardness, pre- or post-operative stent placement, infundibulopelvic angle (IPA), infundibular width (IW), infundibular length (IL), and calyceal pelvic height in terms of pelvicalyceal anatomy using retrograde pyelograms and evaluated the predictive factors of postoperative SF. Results: A total of 173 (56.7%) and 229 (75.1%) patients achieved a SF status on postoperative day one and at one month, respectively. Operation time in the SF group was shorter than that in the non-SF group (51.0 vs. 74.5 min). There were no significant differences in postoperative complications between the SF and non-SF groups. Significantly predictive risk factors in postoperative SF included total stone volume (odds ratio (OR), 1.056; 95% CI, 1.015-1.099; p = 0.007), IPA (OR, 0.970; 95% CI, 0.956-0.993; p = 0.009), and IW (OR, 0.295; 95% CI, 0.121-0.718; p = 0.007). The cut-off values of stone volume, IPA, and IW were 515.2 mm3, 46.8°, and 7.75 mm, respectively. Conclusions: A high-power holmium laser with MT in lower pole stones is a valuable option for positive outcomes and patient's safety. Larger stone volume, acute IPA, and narrow IW were negative predictors related to postoperative SF status.