The role of super-mini percutaneous nephrolithotomy (SMP) in the treatment of symptomatic lower pole renal stones (LPSs) after the failure of shockwave lithotripsy (SWL) or retrograde intrarenal surgery (RIRS)

Relocation of lower pole renal stones helps improve the stone-free rate during flexible ureteroscopy with a low complication rate

OBJECTIVE

To compare the efficacy and safety of relocating the lower pole stones to a favorable pole during flexible ureteroscopy with in situ lithotripsy for the treatment of 10-20 mm lower pole stone (LPS).

METHODS

This study was a prospective analysis of patient outcomes who underwent an FURS procedure for the treatment of 10-20 mm lower pole renal stones from January 2020 to November 2022. The patients were randomized into a relocation group or in situ group. The LPSs were relocated into a calyx, during lithotripsy in the relocation group was performed, whereas the in situ group underwent FURS without relocation. All the procedures were performed by the same surgeon. The patients' demographic data, stone characteristics, perioperative parameters and outcomes, stone-free rate (SFR), complications, and overall costs were assessed retrospectively.

RESULTS

A total of 90 patients were enrolled and analyzed in this study (45 per group) with no significant differences between the two groups in terms of age, gender, BMI, diabetes, hypertension, stone size, number, laterality, composition, and density. The mean operation time, total energy consumption, postoperative stay, and complications were similar between the groups. Both groups had similar SFR at 1 day postoperative follow-up (p = 0.091), while the relocation group achieved significantly higher SFR 3 months later (97.8% vs 84.4%, p = 0.026). The relocation group also had a significantly higher WisQol score than the in situ group (126.98 vs 110.18, p < 0.001).

CONCLUSION

A satisfactory SFR with a relatively low complication rate was achieved by the relocation technique during the FURS procedure.

What Is the Ideal Treatment for 20-30 mm Kidney Stones? Comparative Outcomes of 1197 Patients

Background: The purpose of this study is to compare the efficacy and safety of extracorporeal shockwave lithotripsy (SWL), retrograde intrarenal surgery (RIRS), mini-percutaneous nephrolithotomy (mPNL), and standard-percutaneous nephrolithotomy (stPNL) for the treatment of 20-30 mm kidney stones. Methods: The records of 1197 patients (SWL = 149, RIRS = 205, mPNL = 525, and stPNL = 318) from 8 centers were reviewed retrospectively. Four procedures were compared for stone-free rates (SFRs), auxiliary treatment, and associated complications. Results: Initial SFRs were 43.6%, 54.6%, 86.7%, and 87.7% in SWL, RIRS, mPNL, and stPNL, respectively (P < .001), whereas the final SFRs were 71.8%, 80%, 90.5%, and 89.6% (P < .001). The rate of auxiliary treatment in the groups was 38.3%, 26.8%, 5%, and 4.4%, respectively (P < .001). The initial and final SFRs in the mPNL and stPNL groups were higher than those in SWL and RIRS groups (P < .001). The rate for auxiliary treatment was lower in the mPNL and stPNL groups (P < .001). The operation time was longer in the RIRS group (P = .005). According to the Clavien-Dindo classification, the complication rate in the SWL group was lower than that in the surgical approaches (P < .001); however, no statistical difference was detected between RIRS, mPNL, and stPNL groups. mPNL and stPNL had a higher success rate than RIRS or SWL for treating 20-30 mm kidney stones. Conclusion: In the treatment of 2-3 cm renal stones, RIRS and PNL were more effective than SWL to obtain a better SFR and less auxiliary treatment rate. Compared with RIRS, mPNL and stPNL provided a higher SFR with similar complication rates.

Super-Mini Percutaneous Nephrolithotomy for Nephrolithiasis: A Systematic Review and Meta-Analysis

We aimed to conduct a systematic review and meta-analysis to summarize the current evidence regarding the role of super-mini percutaneous nephrolithotomy (SMP), which refers to a 7-Fr nephroscope placed through a tract sized 10-14 Fr, in treating renal stones and compare its outcomes with the standard mini-percutaneous nephrolithotomy (PCNL) techniques. A systematic literature search was conducted on the Medline database via PubMed and SCOPUS until May 2022 to retrieve the relevant studies. The titles and abstracts of unique records were screened for eligibility, followed by the full-text screening of potentially eligible abstracts. Data extraction was performed by two independent reviewers. The risk of bias assessment was conducted based on the study design. Open Meta (Analyst) and Review Manager 5.4 were used to perform all analyses. A total of 14 studies (n = 4,323 patients) were included, with two randomized controlled trials, one single-arm trial, and 11 cohort studies. The stone-free rate (SFR) of SMP was 91.4%. The pooled analysis showed no significant difference between SFR in mini-PCNL (mean difference (MD) = 1.03, 95% confidence interval (CI) = (0.99, 1.06), p = 0.12) and flexible ureteroscopy (MD = 0.84, 95% CI = (0.4, 1.76), p = 0.65]. On the other hand, SMP had a better SFR rate when compared with retrograde intrarenal surgery (MD = 1.3, 95% CI = (1.01, 1.66), p = 0.04). The pooled mean operative time of SMP was 49.44 minutes (95% CI = (41, 57.88), p < 0.001), which was longer than mini-PCNL (MD = 1.92, p < 0.001) and shorter than ureteroscopy (MD = -17.17, p < 0.00001). In the SMP group, the postoperative complications included fever (>38°C), pain, and hematuria, with an incidence of 7.6%, 2.3%, and 3.4%, respectively. The mean length of hospital stay after SMP was 2.4 days (95% CI = (2.17, 2.7), p < 0.001). The current evidence suggests that SMP is a safe and effective technique in the management of renal stones in both children and adults.

Renal stone density on native CT-scan as a predictor of treatment outcomes in shock wave lithotripsy

Extracorporeal shock wave lithotripsy (ESWL) is considered a standard treatment for nephrolith or kidney stones measuring less than 20 mm. Anatomical, machine-related, and stone factors play pivotal roles in treatment outcomes, the latter being the leading role. This paper examined the relationship between stone density on native CT scans and ESWL treatment to remove renal stones concerning several treatments. One hundred and twenty patients (64 males and 56 females) were enrolled and completed the study from April 2019 to September 2020. Inclusion criteria were a single renal pelvis stone of 5-20 mm to be treated for the first time in adult patients with no urinary or musculoskeletal anatomical abnormalities. We assessed patients' renal function and obtained stone characteristics using a native CT scan. Patients were then scheduled for ESWL by the same machine and operator under fluoroscopy, with two-week intervals between treatment sessions when more than one treatment session was required. Before each new session, a new KUB-US was performed to reevaluate the stone. One hundred and twenty patient records were analyzed, 64 (53.3%) males and 56 (46.7%) females, with a mean age of 38.6 years and a mean stone size of 13.15 mm. Treatment with ESWL cleared stones in 76 (63.3%) patients, while 44 (36.7%) failed the treatment. The mean stone density in patients whose stones were cleared was significantly lower (661 vs. 1001) (P<0.001). Estimating renal calculus (or kidney stone) density on a native CT scan might help prognosticate ESWL treatment outcomes regarding stone clearance rates and the number of sessions required to clear a stone.

Neurogenic Bladder-Induced Stone in a Pelvic Kidney of a Caudal Regression Syndrome Patient: Management of a Complex Case

Percutaneous nephrolithotomy (PCNL) is a difficult treatment for treating kidney stones, especially when there are orthopedic or skeletal abnormalities. Here, in a 19-year-old male, we describe a two-step PCNL with a case of caudal regression syndrome (CRS) and a pelvic kidney, with an extremely deformed neurogenic bladder on intermittent catheterization. Our conclusion is that PCNL may be done safely with minimum morbidity in patients with caudal regression syndrome by utilizing adult equipment for heavy stone burdens, allowing full and rapid stone removal.

Holmium with MOSES technology or Thulium Fiber Laser in Miniperc with suction - A new curiosity

PURPOSE

To present initial clinical comparison between high-power Holmium with MOSES technology(HPH-M) and Thulium Fiber laser(TFL) during mini-PCNL for renal calculi with specific emphasis on fragmentation efficiency, fragment size distribution and stone-free rates(SFR).

MATERIAL AND METHODS

Between Aug2018-Dec2019, we performed mini-PCNL for renal calculi <3cm using HPH-M(Lumenis, Israel) or TFL(Urolase SP, IPG Photonics). Data was collected prospectively in our institutional stone registry. Propensity score matching(1:1) was performed using stone size and density as predictors resulting in matched cohort of 51 patients in each group. MiniPCNL with active suction sheath was standard across all patients. Primary end-point was SFR at immediate post-procedure and 1month using CT/Xray KUB. Stone fragments were retrieved and segregated to assess proportion of dust(<1mm), small(1-3mm) and large(>3mm) fragments.

RESULT

Both groups were comparable in terms of stone size(p=0.74), volume(p=0.17) and density(p=0.69). SFR at 48 hours was 78.43% in HPH-M group and 68.63 % in TFL group. Patients with residual fragments were completely clear at 1month. Lasing time(678.6v/s551.95 seconds;p=0.17), stone fragmentation rate(4.6v/s5.2 mm3/s;p=0.23) and total laser energy(21.9v/s16.3KJ;p=0.09) were comparable in both arms. Both groups produced similar dusting (46.8v/s46.41%;p=0.93). TFL produced a greater proportion of fragments >3mm(36%v/s22.68%, p=0.002). On sub-set analysis based on stone density, all outcome parameters were comparable except a shorter total operative time with TFL (p=<0.05).

CONCLUSION

HPH-M and TFL showed similar SFR. Within constraints of the laser fiber size and energy settings, both modalities were equivalent in terms of fragmentation efficiency and proportion of dusting across stone densities.

Size Distribution of Fragments by High-power Holmium Laser Lithotripsy in MiniPCNL with Suction

PURPOSE OF REVIEW

Data are lacking on distribution of size of fragments created with the laser lithotripsy, stone density, and composition. Dust (< 1 mm) and small fragments (1-3 mm) may be too small to be efficiently removed with forceps compared to larger fragments (> 3 mm). We aim to report the size distribution of fragments formed during holmium laser lithotripsy.

RECENT FINDINGS

One hundred ten patients with renal calculi < 3 cm underwent miniPCNL using ClearPetra sheath (Well Lead Medical Co., China) with controllable irrigation and suction system that minimizes fragment dispersion and maximizes fragment aspiration. Moses holmium laser (Lumenis INC, Israel) was used with predefined laser energy settings for lithotripsy. Proportion of fragment size < 1 mm was 46.36 ± 16.68%, 1-3 mm was 28.18 ± 10.01%, and > 3 mm was 25.19 ± 16.18% for the entire cohort. Complete stone clearance at 48 h was achieved in 77.3% cases. The remaining 22.7% patients had complete clearance at 1-month follow-up CT. In all the stone density, volume, and composition groups, majority of fragments created were either < 1 mm or 1-3 mm. Only 25% fragments were > 3 mm that would get aspirated out through the sheath with suction or could be retrieved with forceps. The combination of a high-power holmium laser and suction would help in complete stone clearance with effective aspiration of smaller stone fragments and dust simultaneously during lasing.

Efficiency of retrograde intrarenal surgery in lower pole stones: disposable flexible ureterorenoscope or reusable flexible ureterorenoscope?

PURPOSE

The primary aim of this study to comparison of reusable and disposable flexible ureterorenoscope (fURS) efficiency in lower pole renal stone disease management. In addition, the secondary goal of this study was to evaluate the factors affecting stone-free rates (SFR) in lower pole stones.

MATERIALS AND METHODS

A prospective case-control study utilizing data from 122 consecutive ureteroscopic cases. The patients were divided into two groups according to the ureterorenoscope employed in the surgical intervention as disposable fURS (Group1, n:52) and reusable fURS (Group 2, n:70). Demographic characteristics, stone size, infundibulopelvic angle (IPA), SFR, hospitalization time, intraoperative complication rate (CR), operative time, preoperative or postoperative JJ stenting, and postoperative CR were analyzed.

RESULTS

There was no statistical difference between the demographic and renal stone-related data between the groups. Likewise, no difference is observed in term of intraoperative and postoperative outcomes such as fluoroscopy time, CR, and hospitalization time between the groups. Although SFR was higher in the disposable fURS group, there was no difference statistically. However, the operative time was longer in reusable fURS Group (47.02 ± 9.91 min in Group 1, and it was 57.97 ± 14.28 in Group 2) (p: 0.001). The multivariate regression analysis result to evaluate the factors of effect to operative time; the use of disposable fURS was associated with a 10.95-min decrease in procedure duration (p < 0.001).

CONCLUSIONS

Disposable fURS and reusable fURS have similar clinical efficiency and complication rates in the treatment of lower calyceal stones with RIRS. Nevertheless, disposable fURS is a useful treatment option for increased stone volume due to the advantages such as shorter operative time.

Comparative analysis of retrograde intrarenal surgery and modified ultra-mini percutaneous nephrolithotomy in management of lower pole renal stones (1.5-3.5 cm)

Background

To compare the safety and efficacy of retrograde intrarenal surgery (RIRS) and modified Ultra-mini percutaneous nephrolithotomy (UMP) in semi-supine combined lithotomy position for the management of 1.5–3.5 cm lower pole renal stones (LPSs).

Methods

A total of 63 patients with 1.5–3.5 cm LPSs who underwent RIRS (n = 33) or modified UMP (n = 30) in diameter between January 2017 and January 2019 were analyzed retrospectively. Modified UMP was performed in semi-supine combined lithotomy position and a 9.5/11.5 F ureteral access sheath (UAS) was inserted during the procedure in order to maintain low pelvic pressure and to facilitate the removal of stone fragments. Base-line parameters, stone characteristics, illness condition, operation time, postoperative hemoglobin (Hb) drop, postoperative creatinine (Cr) elevation, length of hospital stay, length of postoperative hospital stay, stone-free rate (SFR) and complications were compared between the two groups.

Results

There were no significant differences between the two groups in base-line parameters, stone characteristics and illness condition. The mean operating time of RIRS group was longer than UMP group (95.61 ± 21.9 vs. 55.0 ± 16.1 min, p < 0.001). The mean postoperative Hb drop was less in RIRS group (7.42 ± 4.7 vs. 15.70 ± 9.8 g/L, p < 0.001). The length of hospital stay and postoperative hospital stay for RIRS were shorter than UMP (4.76 ± 1.1 vs. 5.83 ± 0.8 d, p < 0.001, 2.97 ± 0.9 vs. 4.07 ± 0.9 d, p < 0.001). The Early SFR was higher in UMP group (54.5 vs. 80.0%, p < 0.050) while SFR at 1-month and 3-months postoperatively was similar in both groups (p = 0.504, p = 0.675). There were no significant differences between the two groups in complications (p = 0.228).

Conclusion

For patients with 1.5–3.5 cm LPSs, both modified UMP and RIRS are safe and viable. The modified UMP technique was used in this study, application semi-supine combined lithotomy position and the retention of UAS can improve the surgical efficiency and maintain low pressure perfusion in the kidney, which resulted in superior treatment efficacy. Therefore, we highly recommend this technique for LPSs with heavy stone burdens.

Evaluation of flexible ureteroscope with an omni-directional bending tip, using a JOYSTICK unit (URF-Y0016): an ex-vivo study

PURPOSE

To compare the range of reach of our newly designed omni-directional ureteroscope (URF-Y0016), compared to the commonly used URF-P6, FlexX2s, and LithoVue™ scopes, in the upper, middle, and lower calyces in an ex-vivo pyelocaliceal model.

METHODS

We fabricated a three-dimensional pyelocaliceal model of the upper, middle, and lower pole calyces using urethane and acrylic resin. The inner surface of the dome of each calyx was engraved with reference lines along eight directions, set at 10° of latitude from the top to the base of the dome, and at angles of 0-90°, to precisely determine the range of reach of each scope. The main feature of the URF-Y0016 scope is the omni-directional bending of the tip of the flexible ureteroscope, with the control of these four directions integrated into a handgun-type control unit with a joystick. The range of reach within each calyx was measured by four expert surgeons.

RESULTS

The URF-Y0016 scope provided a greater range of reach along all directions in the lower pole calyx compared to URF-P6, FlexX2s, and LithoVue™ scopes (p < 0.001), particularly along the anterior-posterior direction in the lower lobe calyx. However, the URF-Y0016 scope did not influence the improvement of reach range in the upper and middle pole calyx compared to URF-P6, FlexX2s, and LithoVue™ scopes (p = 0.08, p = 0.296).

CONCLUSION

The novel design of the URF-Y0016 could improve treatment outcomes for calyceal stones in the lower pole in practice.