Results from a Single-surgeon Large Series

Background and objective

Percutaneous nephrolithotomy (PCNL) is the recommended treatment for large or complex renal stones. This study aims to evaluate the outcomes of mini PCNL in obese and nonobese patients and to compare the outcomes of mini and standard PCNL in the obese population.

Methods

We retrospectively reviewed our PCNL database to identify patients who had undergone mini (Amplatz sheath size 17.5Ch) or standard (Amplatz sheath size ≥26Ch) PCNL between 2005 and 2022. First, we compared the outcomes of the two procedures in the obese (body mass index [BMI] ≥30) and nonobese (BMI<30) patients. Second, we compared the outcomes of mini and standard PCNL in the obese population. A multivariable logistic regression analysis was performed to assess the variables associated with stone-free rate (SFR) and complications.

Key findings and limitations

A total of 781 patients underwent mini PCNL; there was no difference between nonobese (578) and obese (133) patients in surgical time, number of tubeless procedures, postoperative stay, SFR, and overall complication rates. Similar outcomes were also seen in the 356 patients who had undergone standard PCNL, including 276 nonobese and 80 obese patients. The comparison of mini and standard PCNL in the obese population (213 patients) showed that mini PCNL provided significant benefits in surgical time (60 vs 94 min), SFR (85% vs 63.8%), and blood transfusion rate (2% vs 10%). The multivariable analysis confirmed that mini PCNL resulted in significantly higher odds of being stone free (odds ratio [OR] 1.79) and lower odds of having a blood transfusion (OR 0.28).

Conclusions and clinical implications

Obese patients can safely undergo either mini or standard PCNL; in this series, mini performed better than standard PCNL in terms of SFR and blood transfusion rates.

Patient summary

In this study, we compared the outcomes of mini and standard percutaneous nephrolithotomy (PCNL) in the obese population. We found that mini PCNL had lower surgical time and blood transfusion rate, and better stone-free rate than its standard counterpart in obese patients.

Comparison between standard, mini and ultra-mini percutaneous nephrolithotomy for single renal stones: a prospective study

PURPOSE

Based on the current trend of miniaturization of instruments used in percutaneous nephrolithotomy (PCNL), it is necessary to compare different PCNL modalities regarding their access sheath size used. Thus, the safety and efficacy among standard, mini and ultra-mini PCNL (s-PCNL, m-PCNL, um-PCNL) were compared.

METHODS

We performed a prospective, non-randomized trial between January 2018 and July 2020. Patients with stones classified as Guy's stone score grade I were included. The set-up for s-PCNL and m-PCNL included a 30 Fr and 22 Fr percutaneous tract, respectively. In both set-ups, an ultrasonic/ballistic lithotripter was utilized. In the case of um-PCNL, a 12 Fr percutaneous tract was established. A high-power laser was used for lithotripsy. Hemoglobin drop, complication rate, length of hospital stay (LOS), stone-free rate (SFR) and operation time were evaluated.

RESULTS

A total of 84 patients, 28 patients per method, were evaluated. Hemoglobin drop was higher in the s-PCNL group when compared to m-PCNL (p = 0.008) and um-PCNL groups (p < 0.001), while um-PCNL group had the slightest hemoglobin drop. LOS was similar between s-PCNL group and m-PCNL group, but um-PCNL group required shorter hospital stay than the other two modalities (p < 0.001). The complication and transfusion rates as well as SFR did not differ between groups. Operation time in the um-PCNL set-up was longer compared to s-PCNL (p < 0.001) and m-PCNL (p = 0.011), whereas s-PCNL and m-PCNL did not differ significantly.

CONCLUSION

m-PCNL showed less hemoglobin drop, but similar operation time and SFR when compared to s-PCNL. um-PCNL showed even less hemoglobin drop, but the operation time was longer compared to the two other modalities.

Comparison of miniaturized percutaneous nephrolithotomy and standard percutaneous nephrolithotomy for the treatment of large kidney stones: a randomized prospective study

We aimed to compare the outcomes of mini-percutaneous nephrolithotomy (mPNL) and standard PNL techniques in the treatment of renal stones ≥ 2 cm. The study was designed as a randomized prospective study between January 2016 and April 2017. The patients with a kidney stone ≥ 2 cm were included in the study. Patients who had uncorrectable bleeding diathesis, abnormal renal anatomy, skeletal tract abnormalities, pregnant patients and pediatric patients (< 18 years old) were excluded from the study. The remaining patients were randomly divided into two groups as standard PNL and mPNL. For both group, demographic data, stone characteristics, operative data and postoperative data were recorded prospectively. The study included 160 consecutive patients who had kidney stone ≥ 2 cm. Of these, patients who met the exclusion criteria and patients who had missing data were excluded from the study. Remaining 97 patients were randomly divided into two groups as mPNL (n: 46) and standard PNL (n: 51). The mean age was 46.9 ± 13.7 and 47.4 ± 13.9 years for mPNL group and sPNL group, respectively. According to Clavien-Dindo classification, no statistical difference was detected between the groups in terms of complication rates (p 0.31). However, the rates of hemoglobin drop and transfusion rates were significantly in favour of mPNL (p 0.012 and p 0.018, respectively). Nephrostomy time and hospitalization time was found to be significantly shorter in mPNL group (p 0.017 and p 0.01, respectively). The success rate in the mPCNL group was higher than standard PNL group, however, this difference was statistically insignificant (76.5 vs 71.7%, p 0.59). Both mPNL and standard PNL are safe and effective treatment techniques for the treatment of kidney stones of ≥ 2 cm. Although there was no significant difference in success rates of both techniques; nephrostomy time, hospitalization time, bleeding and transfusion rates were in favour of mPNL.

Ultra-mini-percutaneous nephrolithotomy (PCNL) versus standard PCNL: A randomised clinical trial

Objective

To assess the effectiveness and advantages of ultra-mini-percutaneous nephrolithotomy (UM-PCNL) versus standard PCNL (S-PCNL), as one of the most important differences between the various PCNL techniques is the size of the renal access, which contributes to the broad spectrum of complications and outcomes.

Patients and methods

This clinical randomised trial was conducted in 2016. In all, 70 patients with renal or upper ureteric stones of 10–20 mm in diameter, who were candidates for PCNL, were divided equally into two groups. Group A, underwent UM-PCNL using a 9.8-F ureteroscope through a 16-F sheath; and Group B, underwent S-PCNL using a 24-F nephroscope through a 30-F sheath. The stones were fragmented by pneumatic lithotripsy. Any perioperative complications and need for analgesia were recorded, and postoperative pain was assessed in both groups using a visual analogue scale (VAS).

Results

There were statistically significant differences in postoperative haemoglobin values, haemoglobin drop, transfusion rate, duration of hospitalisation and postoperative VAS pain score between the groups (P < 0.05). There were no significant differences in operation time, need for auxiliary procedures or stone-free rate.

Conclusion

A minimally invasive UM-PCNL using a 9.8-F ureteroscope can play an important role in the treatment of symptomatic renal and upper ureteric stones of <20 mm in diameter with lesser blood loss, duration of hospitalisation, need of transfusion, and postoperative pain compared with S-PCNL.

Minimally invasive percutaneous nephrolithotomy vs standard PCNL for management of renal stones in the flank-free modified supine position: single-center experience

To assess the safety and efficacy of minimally invasive percutaneous nephrolithotomy (mPCNL) as compared to standard PCNL (sPCNL) for management of 2-3-cm renal stones in the flank-free modified supine position. Between September 2010 and December 2013, 150 patients (168 renal units) with 2-3-cm renal stones were prospectively randomized into two treatment groups; Group A (75 patients/87 renal units) treated by mPCNL and Group B (75 patients/81 renal units) treated by sPCNL. In both groups, the patients were placed in the flank-free modified supine position. In mPCNL group, the tract was dilated up to 16.5 F whereas in sPCNL group the tract was dilated up to 30 F. Both groups were compared regarding several perioperative parameters. No significant difference was recorded among both groups regarding fluoroscopy time (4.3 ± 1.3 vs 4.8 ± 2.1 min, p = 0.06), operative time (83.2 ± 17.3 vs 78.6 ± 24.4 min, p = 0.16), hospital stay (4.3 vs 4.5 days, p = 0.76), VAS score (3.2 ± 0.6 vs 3.3 ± 0.8, p = 0.36) and need for analgesia. The mean drop in hemoglobin level and the incidence of bleeding that necessitated blood transfusion were significantly lower in the mPCNL group (0.6 ± 0.1 vs 1.9 ± 1.1 g/dl, p < 0.0001 and 1.2 vs 9.8%, p = 0.03, respectively). Although the stone-free rate was higher in the sPCNL group, but this was statistically insignificant (97.1 vs 95.4%, p = 0.86). Mini-PCNL is effective for managing renal calculi with comparable operative time and stone-free rate to standard PCNL with the merit of higher safety due to lower incidence of bleeding that necessitates blood transfusion.

Comparison of complications associated with standard and totally tubeless percutaneous nephrolithotomy according to modified Clavien grading: a multicenter retrospective study

The aim of this study was to compare the complications of standard and totally tubeless percutaneous nephrolithotomy (PCNL) based on the modified Clavien complication grading system. We retrospectively evaluated the complications of 290 consecutive patients who had undergone standard or totally tubeless PCNL at four institutes between January 2010 and August 2012 based on the modified Clavien scale. The totally tubeless cases were classified as Group 1 and the cases to which a Malecot re-entry catheter was applied were classified as Group 2. The postoperative complications were recorded according to the modified Clavien complication grading system. Statistically significant differences were observed only in the first-degree injury class between the two groups based on the modified Clavien classification. The requirement for blood transfusion and prolonged percutaneous access site leakage were more frequent in Group 2, but these differences were not statistically significant. We also performed a pain evaluation by monitoring postoperative analgesia demands. In Group 1, the analgesic demand rates in the 1(st) and 6(th) postoperative hours were 64.6% and 31.5%, respectively. In Group 2, the analgesic demand rates were 87.5% and 58.75% in the 1(st) and 6(th) postoperative hours, respectively. The mean ± standard deviation of analgesic doses in the first 6 hours was 0.96 ± 0.7 and 1.46 ± 0.6 in Groups 1 and 2, respectively. These differences were statistically significant. Based on our results, we can conclude that the tubeless technique has fewer complications, improved postoperative patient comfort, shorter hospitalization times, and a reduced need for analgesics, suggesting that tubeless PCNL should be the standard approach. For suitable cases, this technique may be used safely as the standard PCNL approach.