Percutaneous Nephrolithotomy in Patients with Urinary Tract Abnormalities

Mini-percutaneous nephrolithotomy: Is smaller better for kidney stones in patients with neurogenic bladder?

INTRODUCTION

Patients with neurologic bladder are at an increased risk for urolithiasis, and currently, data on mini-percutaneous nephrolithotomy in this population are limited. Our objective was to compare mini (15F)-percutaneous nephrolithotomy, standard (24F)-PCNL and flexible ureteroscopy in terms of efficacy and safety in treatment of kidney stones in patients with neurogenic lower urinary tract dysfunction (NLUTD).

METHODS

We conducted a retrospective monocentric study in our neuro-urological referral centre. All consecutive patients with NLUTD and a cumulative size of renal calculi greater than 15mm or 10mm in the lower calyx, who had extraction surgery between 2005 and 2020, were included. The primary endpoint was the one-session stone-free rate (SFR) at 3 months on a CT scan. The secondary endpoints were complication (Clavien-Dindo grading system), operative time, blood loss and length of hospital stay.

RESULTS

We performed 76 standard PCNL (sPCNL), 46 flexible ureteroscopy lithotripsy (fURL) and 25 miniaturized PCNL (mPCNL). The one-session SFR was 37.5% for the mPCNL group, 38.2% for the sPCNL group and 37% for the fURL group with no significant difference between the three procedures (P=0.99). Early complications, blood loss and transfusion rates were lower in the mPCNL group than in the sPCNL group (P=0.047) and comparable to fURL group. The final SFRs after a second intervention for mPCNL, sPCNL and fURL were 48%, 61.8% and 63%, respectively (P=0.67).

CONCLUSION

The efficacy of mPCNL in patients with NLUTD was not different from other techniques, but a significantly lower rate of complications than sPCNL was observed.

LEVEL OF PROOF

3.

Stone Burden Measurement by 3D Reconstruction on Noncontrast Computed Tomography Is Not a More Accurate Predictor of Stone-Free Rate After Percutaneous Nephrolithotomy Than 2D Stone Burden Measurements

Purpose: Stone burden has been reported as an independent predictor of stone-free rate after percutaneous nephrolithotomy (PCNL); however no consensus exists on a standardized method for measuring stone burden. Recently, stone volume has been advocated as the most accurate means of measuring stone burden. We aimed to compare different measuring methods of stone burden and to identify the predictive value of each for outcomes after PCNL. Materials and Methods: We performed a retrospective review of a prospective database of patients who underwent PCNL between 2006 and 2013. A preoperative CT and postoperative imaging at discharge were necessary for eligibility. Stone burden was assessed through four different ways on CT images: (1) cumulative stone diameter; (2) estimated SA (surface area) calculated as longest × orthogonal diameter × π/4; (3) manual outline of stone and computer SA calculation; and (4) automated 3D volume calculation using specific software. Primary outcome was stone-free status (SFS) at discharge. Secondary outcomes included operative time and the need for an ancillary procedure. Regression analysis and receiver operating characteristic curve analysis were used to evaluate the predictive value of each method. Results: Of 313 included patients, 69.6% were stone free at discharge. All measures of stone burden were independent predictors of SFS [OR and 95% CI of 1.027 (1.014, 1.040), 1.481 (1.180, 1.858), 1.736 (1.266, 2.380), and 1.311 (1.127, 1.526), respectively] and demonstrated similar predictive accuracy (area under the curve = 0.630, 0.630, 0.627, and 0.638, respectively). Stone burden by any measure was an independent predictor of operative time and secondary procedure. Conclusions: We demonstrated that measuring stone burden by manual outline or automated 3D volume on reformatted CT images had no added value compared with orthogonal measurement for predicting outcomes after PCNL.

Costs variations for percutaneous nephrolithotomy in the U.S. from 2003-2015: A contemporary analysis of an all-payer discharge database

INTRODUCTION

We sought to evaluate population-based costs variations and predictors of outlier costs for percutaneous nephrolithotomy (PCNL) in the U.S.

METHODS

Using the Premier Healthcare Database, we identified all patients diagnosed with kidney/ureter calculus who underwent PCNL from 2003-2015. We evaluated 90-day direct hospital costs, defining high- and low-cost surgery as those >90th and <10th percentile, respectively. We constructed a multilevel, hierarchical regression model and calculated the pseudo-R² of each variable, which translates to the percentage variability contributed by that variable on 90-day direct hospital costs.

RESULTS

A total of 114 581 patients underwent PCNL during the 12-year study period. Mean cost in the low-cost group was $5787 (95% confidence interval [CI] 5716-5856) vs. $38 590(95% CI 37 357-39 923) in the high-cost group. Cost variations were substantially impacted by patient (63.7%) and surgical (18.5%) characteristics and less so by hospital characteristics (3.9%). Significant predictors of high costs included more comorbidities (≥2 vs. 0: odds ratio [OR] 1.81; p=0.01) and hospital region (Northeast vs. Midwest: OR 2.04; p=0.03). Predictors of low cost were hospital bed size of 300-499 beds (OR 1.35; p<0.01) and urban hospitals (OR 2.77; p=0.01). Factors less likely to be associated with low-cost PCNL were more comorbidities (Charlson Comorbidity Index [CCI] ≥2: OR 0.69; p<0.0001), larger hospitals (OR 0.61; p=0.01), and teaching hospitals (OR 0.33; p<0.0001).

CONCLUSIONS

Our contemporary analysis demonstrates that patient and surgical characteristics had a significant effect on costs associated with PCNL. Poor comorbidity status contributed to high costs, highlighting the importance of patient selection.

Two Are No Different Than One: Ureteral Duplication Appears to Have No Effect on Ureteroscopy Outcomes

INTRODUCTION

Ureteral duplication is the most common ureteral anomaly, occurring in 0.6%-0.7% of the population. Our objective was to compare urolithiasis treatment outcomes in patients with and without ureteral duplication.

METHODS

Patients with ureteral duplication who underwent ureteroscopy (URS) were identified in a stone registry at a high-volume, tertiary care center from 1998 to 2015. Preoperative, intraoperative, and postoperative data were collected retrospectively. A 1:1 control cohort of patients without duplication was identified, matched by stone location and size, as well as age, body mass index (BMI), and gender. Clinical data and outcomes were compared between duplication and control groups, between partial and complete duplication groups, and between patients in whom duplication was identified intraoperatively vs known preoperatively.

RESULTS

Fifty patients with ureteral duplication who underwent URS were identified and were matched to 50 control patients. Patients with ureteral duplication required longer operative time (55 minutes vs 38.5 minutes, p = 0.022). Ureteral duplication had no effect on stone-free rates or need for additional procedures. High-grade (Clavien 4-5) complications were similar in both groups (4% vs 4%). Location of ureteral duplication and preoperative knowledge of ureteral duplication did not affect operative time or stone-free rates.

CONCLUSIONS

Patients with ureteral duplication undergoing URS for urinary stone disease have longer operative times. Preoperative knowledge of ureteral duplication appears to have no significant effect on URS's safety or efficacy. In patients without a prior diagnosis of ureteral duplication, our data suggest that intraoperative detection via endoscopy and fluoroscopy is sufficient to safely and completely treat stone disease.

Prone Versus Supine Percutaneous Nephrolithotomy: What Is Your Position?

PURPOSE OF REVIEW

Percutaneous nephrolithotomy (PCNL) is the gold standard surgical procedure for treating large, complex renal stones. Due to its challenging nature, PCNL has undergone many modifications in surgical technique, instruments, and also in patient positioning. Since the first inception of PCNL, prone position has been traditionally used. However, alternative positions have been proposed and assessed over the years. This is a comprehensive review on the latest developments related to positioning in the practice of PCNL.

RECENT FINDINGS

The prone position and its modifications are the most widely used positions for PCNL, but with the introduction of various supine positions, the optimal position has been up for debate. Recent meta-analysis has shown a superior stone-free rate in the prone position and comparable complication rates to the supine position. The advantage of ease of access to the urethra for simultaneous retrograde techniques in the supine position is also possible with modifications in the prone position such as the split-leg technique. Modern-day PCNL has transformed from an operation traditionally undertaken in the prone position to a procedure in which a prone or supine position may be employed; however, published data have not shown significant superiority of either approach.

Positioning for percutaneous nephrolithotomy

PURPOSE OF THE REVIEW

To highlight the progressive evolution of the issue of patient positioning for percutaneous nephrolithotomy (PNL), explain the history of the prone and supine positions, report respective advantages and drawbacks, critically interpret the past and current literature supporting such arguments, identify the best candidates for each position, and reflect on the future evolution of the two approaches.

RECENT FINDINGS

Positioning for PNL has become a matter of debate during the last decade. The traditional prone PNL position - most widely performed with good success and few complications, and exhibiting essentially no limits except for the treatment of pelvic kidneys - is nowadays flanked mainly by the supine and supine-modified positions, equally effective and probably safer from an anesthesiological point of view. Of course, both approaches have a number of advantages and drawbacks, accurately reported and critically sieved.

SUMMARY

The current challenge for endourologists is to be able to perform PNL in both prone and supine positions to perfectly tailor the procedure on any patient with any stone burden, including increasingly challenging cases and medically high-risk patients, according to the patient's best interest. Intensive training and experience is especially needed for supine PNL, still less popular and underperformed worldwide.

VIDEO ABSTRACT

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Risk Factors for Postoperative Complications of Percutaneous Nephrolithotomy at a Tertiary Referral Center

PURPOSE

We sought to describe and evaluate the complications related to percutaneous nephrolithotomy and identify risk factors of morbidity according to the modified Clavien scoring system. We also sought to specify which perioperative factors are associated with minor and major complications.

MATERIALS AND METHODS

We retrospectively analyzed data on patients who underwent percutaneous nephrolithotomy from 1990 to 2013. Descriptive statistics were used to analyze patient characteristics, medical comorbidities and perioperative features. Complications were categorized according to the Clavien score for percutaneous nephrolithotomy. The Mann-Whitney and Fisher exact tests were used as appropriate. Logistic regression analysis was performed to look for prognostic factors associated with major complications.

RESULTS

A total of 2,318 surgeries were evaluated. Mean age of the population was 53.7 years. The stone-free rate at hospital discharge was 81.6%. The overall complication rate was 18.3%. Two deaths occurred. Patients with any postoperative complications were older, had more comorbidities, were more likely to have staghorn calculi and had longer operative time and hospital stay on univariate analysis (p<0.05). Age 55 years or older and upper pole access were independent predictors of major complications on multivariate analysis. Other factors such as a history of urinary tract infections, body mass index, stone composition, previous percutaneous nephrolithotomy and multiple tracts were not associated with a major complication.

CONCLUSIONS

At our center percutaneous nephrolithotomy is an excellent option for complex kidney stone management with a low overall complication rate. Older patient age and upper pole access are significantly associated with an increased risk of a major complication.