Safety and efficacy of minimally invasive percutaneous nephrolithotomy in treatment of calculi in horseshoe kidneys

Optimal patient position for percutaneous nephrolithotomy in horseshoe kidneys: Traditional prone or supine?

OBJECTIVE

Although it was stated that supine percutaneous nephrolithotomy (PCNL) was associated with relatively shorter surgical times and comparable success and complication rates, there is no consensus in the current literature concerning the safety and efficacy of supine PCNL in patients with horseshoe kidneys. We aimed to compare supine and prone PCNL regarding safety and efficacy in patients with horseshoe kidneys.

METHODS

Data of the patients with horseshoe kidneys who underwent PCNL for renal stones larger than 2 cm between January 2010 and May 2021 were retrospectively reviewed. The study patients were categorized as Group 1 (i.e., supine PCNL-SPCNL) and Group 2 (i.e., prone PCNL-PPCNL). Both groups were compared regarding demographic, clinical, and surgical data.

RESULTS

Sixty-five patients were included. Among these patients, 31 (47.7%) were in Group 1, while 34 (52.3%) were in Group 2. Both groups were statistically similar in terms of demographic data, stone characteristics, perioperative parameters, and complication rates (p > 0.05). There was no statistical difference in terms of additional treatment rates, stone-free rates in the postoperative second-day and third-month evaluations (p > 0.05). Mean surgical time was significantly longer in Group 2 (113 ± 17.1 min) than in Group 1 (90.6 ± 11.3 min) (p = 0.000).

CONCLUSION

Although it is traditionally performed in the prone position, the supine approach is as safe and effective as the prone approach. In addition, the supine approach is associated with significantly shorter surgical times.

Management of staghorn stones in special situations

Staghorn stones have always been a challenge for urologists, especially in some special situations, such as horseshoe kidney, ectopic kidney, paediatric kidney, and solitary kidney. The treatment of these staghorn stones must be aggressive because they can lead to renal function loss and serious complications. The gold-standard management for staghorn stones is surgical treatment with the aim of clearing the stones and preserving renal function. Treatment methods for staghorn stones have developed rapidly, such as extracorporeal shock wave lithotripsy, retrograde intrarenal surgery, percutaneous nephrolithotomy and laparoscopy and open surgery. Whether the standard procedures for staghorn stones can also apply to these stones in special situations is still not agreed upon. The decision should be made individually according to the circumstances of the patient. In this review, we evaluates the previous studies and comments on the management of staghorn stones under special situations in the hope of guiding the optimal choice for urologists.

Miniaturised percutaneous nephrolithotomy: Its role in the treatment of urolithiasis and our experience

Miniaturized percutaneous nephrolithotomy (PCNL) procedures have gained increased popularity in recent years. They aim to reduce percutaneous tract size in order to lower complication rates, while maintaining high stone-free rates. Recently, miniaturized PCNL techniques have further expanded, and can currently be classified into mini-PCNL, minimally invasive PCNL (MIP), Chinese mini-PCNL (MPCNL), ultra-mini-PCNL (UMP), micro-PCNL, mini-micro-PCNL, and super-mini-PCNL (SMP). However, despite its minimally-invasive nature, its potential superiority in terms of safety and efficacy when compared to conventional PCNL is still under debate. The aim of this review is to summarise different available modalities of miniaturized PCNL, details of instruments involved, and their corresponding safety and efficacy. In particular, this article highlights the role of the SMP and our experience with this novel technique in management of urolithiasis. Overall, miniaturized PCNL techniques appear to be safe and effective alternatives to conventional PCNL for both adult and pediatric patients. Well-designed, randomized studies are required to further investigate and identify specific roles of miniaturized PCNL techniques before considering them as standard rather than alternative procedures to conventional PCNL.

Incidence and characteristics of kidney stones in patients with horseshoe kidney: A systematic review and meta-analysis

Introduction

The horseshoe kidney (HSK) is the most common type of renal fusion anomaly. The incidence and characteristics of kidney stones in patients with HSK are not well studied. The aim of this meta-analysis was to evaluate the incidence and types of kidney stones in patients with HSK.

Methods

A systematic literature search was performed using MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews from the databases' inception through November 2016. Studies assessing the incidence and types of kidney stones in patients with HSK were included. We applied a random-effects model to estimate the incidence of kidney stones. The study protocol was registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42016052037).

Results

A total of 14 observational studies with 943 patients (522 adults and 421 pediatric) with HSK were enrolled. The estimated pooled incidence of kidney stones was 36% (95% confidence interval [CI], 15%-59%) in adults with the HSK. Kidney stones were less common in pediatric patients with HSK with an estimated pooled incidence of 3% (95% CI, 2%-5%). The mean age of adult stone formers with HSK was 44.9 ± 6.2 years, and 75% were males. Within reported studies, 89.2% of kidney stones were calcium-based stones (64.2% calcium oxalate [CaOx], 18.8% calcium phosphate [CaP], and 6.2% mixed CaOx/CaP), followed by struvite stones (4.2%), uric acid stones (3.8%), and others (2.8%).

Conclusions

Kidney stones are very common in adult patients with HSK with an estimated incidence of 36%. Calcium-based stones are the most prevalent kidney stones in adults with HSKs. These findings may impact the prevention and clinical management of kidney stones in patients with HSK.

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.

Predictors for uroseptic shock in patients who undergo minimally invasive percutaneous nephrolithotomy

To identify risk factors that can predict which patient is likely to progress from systemic inflammatory response syndrome (SIRS) to uroseptic shock after minimally invasive percutaneous nephrolithotomy (MPCNL) for the upper urinary tract stones. We retrospectively reviewed 156 patients who suffered infectious complications after MPCNL from March 2014 to February 2016. Perioperative risk factors that could potentially contribute to uroseptic shock were compared to those of patients with only SIRS. 135 of the 156 patients developed to SIRS only, the remaining 21 patients progressed to uroseptic shock. The rate of positive preoperative urine nitrite was significantly higher (p < 0.001), stone diameter was larger (p = 0.015) and operative time was longer (p < 0.001) in uroseptic shock group. Multivariable logistic analysis showed that preoperative urine nitrite (OR 10.570, p = 0.025), stone size (OR 11.512, p = 0.009) and postoperative blood leukopenia (OR 0.009, p < 0.001) were independently related to uroseptic shock. Moreover, ROC curve analysis showed that white blood count threshold within the first 3 h of uroseptic shock was 2.98 × 10⁹/L. The sensitivity and specificity of leukocyte count in predicting uroseptic shock were 90.5 and 92.6%, respectively. Preoperative urine nitrite, stone size and postoperative leukocyte count are statistically linked to uroseptic shock after MPCNL. Leukopenia of less than 2.98 × 10⁹/L within 3 h after MPCNL can be a predictor for uroseptic shock. For patients who have high risk factors for developing uroseptic shock, the white blood count should be measured within 3 h after MPCNL.

Comparison of renal pelvic pressure and postoperative fever incidence between standard- and mini-tract percutaneous nephrolithotomy

This study was proposed to compare the clinical effectiveness of mini-tract percutaneous nephrolithotomy (MPCNL) with standard-tract percutaneous nephrolithotomy (SPCNL) and verify whether MPCNL is associated with both higher renal pelvic pressure (RPP) and incidence of postoperative fever. A total of 228 patients with kidney stone were randomly allocated to the MPCNL group (n=114) and SPCNL group (n=114). Both intraoperative and postoperative indexes along with the incidence of complications were compared between the two treatment groups. RPP was measured using a baroreceptor which was connected to an open-ended ureteric catheter during the operation of percutaneous nephrolithotomy. The MPCNL group exhibited significantly longer average operation time, more average amount of flush water, and lesser average amount of bleeding during the operation than the SPCNL group (p<0.05). Moreover, significantly lesser average amount of postoperative serum creatinine, shorter average hospital stay, and more average amount of postoperative hemoglobin were observed in the MPCNL group than in the SPCNL group (p<0.05). MPCNL were more applicable to clear caliceal stones (p<0.05), whereas SPCNL were more effective for the removal of simple pelvic stones. The difference in the incidence of postoperative fever between the two treatment groups also appeared to be significant (p<0.05). Logistic regression provided solid evidence that both RPP and its accumulation time at which RPP≥30 mmHg significantly affected the incidence of postoperative fever. MPCNL was correlated with both higher RPP and increased likelihood of postoperative fever compared with SPCNL.

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

http://links.lww.com/COU/A8.

Endoscopic Management of Urolithiasis in the Horseshoe Kidney

OBJECTIVE

To assess the endourologic outcomes of patients diagnosed with a horseshoe kidney (HK) and symptomatic urolithiasis.

METHODS

A retrospective review was performed of patients diagnosed with an HK who underwent endoscopic management from 2002 to present.

RESULTS

We identified 45 patients with 64 stone-bearing moieties who underwent 56 procedures, of which 31 (69%) were male. Mean age was 49.4 years (23-78) and mean stone size was 1.6 cm (0.2-5.7). Of the 64 moieties, 37 (58%) underwent percutaneous nephrolithotomy (PCNL), 25 (39%) underwent ureteroscopy (URS), and 2 (3%) underwent extracorporal shockwave lithotripsy (SWL). More than one access was utilized in 2 (5.7%) moieties undergoing PCNL. Additional procedures were required in 10 (28.5%) PCNL patients, of which 7 were URS, 2 were secondary PCNL, and 1 sandwich therapy with SWL and PCNL. Stone-free rate by moiety was 81.1% for PCNL, 84% for URS, and 50% for SWL. Postoperative complications occurred in 3 patients in the PCNL group, including readmission for pain and complicated urinary tract infection. With a mean follow-up of 20.5 months (range 0-118 months), stone recurrence was noted in 7 (16%) patients with a total of 11 events. Calcium oxalate was the most common stone type and 20/24 (83%) of patients with metabolic evaluations were found to have at least one abnormality.

CONCLUSION

After careful consideration of the anatomy, individuals with HK and symptomatic urolithiasis can be managed safely by a variety of endoscopic approaches with excellent outcomes; however, secondary procedures and recurrence are common.

Oxidative Damage and Mitochondrial Injuries Are Induced by Various Irrigation Pressures in Rabbit Models of Mild and Severe Hydronephrosis

OBJECTIVE

We aimed to study whether tolerance to irrigation pressure could be modified by evaluating the oxidative damage of obstructed kidneys based on rabbit models experiencing different degrees of hydronephrosis.

METHODS

A total of 66 rabbits were randomly divided into two experimental groups and a control group. In the experimental groups, the rabbits underwent a surgical procedure inducing mild (group M, n=24) or severe (group S, n=24) hydronephrosis. In each experimental group, the rabbits were then randomly divided into 4 subgroups (M0-M3 and S0-S3) consisting of 6 rabbits each. Group 0 received no perfusion. Groups 1 through 3 were perfused with 20, 60 and 100 mmHg fluid, respectively. For the control group, after a sham operation was performed, the rabbits were divided into 4 subgroups and were perfused with fluid at 0, 20, 60 or 100 mmHg of pressure. Kidney injuries was evaluated by neutrophil gelatinase associated lipocalin (NGAL). Oxidative damage was assessed by analyzing superoxide dismutase (Mn-SOD) activity, malondialdehyde (MDA) levels, glutathione reductase (GR), catalase (CAT) and peroxide (H2O2) levels, mitochondrial injuries was assessed by mitochondrial membrane potential (MMP), the mitochondrial ultrastructure and tubular cell apoptosis.

RESULTS

In the experimental groups, all results were similar for groups 0 and 1. In group 2, abnormalities were observed in the S group only, and the kidneys of rabbits in group 3 suffered oxidative damage and mitochondrial injuries with increased NGAL, decreased Mn-SOD, GR and CAT,increased MDA and H2O2, lower levels of MMP, mitochondrial vacuolization and an increased apoptotic index.

CONCLUSION

In rabbits, severely obstructed kidneys were more susceptible to oxidative damage and mitochondrial injury than mildly obstructed kidneys when subjected to higher degrees of kidney perfusion pressure.