Percutaneous Management of Staghorn Calculi in Horseshoe Kidneys: A Multi-Institutional Experience

A novel post-percutaneous nephrolithotomy sepsis prediction model using machine learning

OBJECTIVES

To establish a predictive model for sepsis after percutaneous nephrolithotomy (PCNL) using machine learning to identify high-risk patients and enable early diagnosis and intervention by urologists.

METHODS

A retrospective study including 694 patients who underwent PCNL was performed. A predictive model for sepsis using machine learning was constructed based on 22 preoperative and intraoperative parameters.

RESULTS

Sepsis occurred in 45 of 694 patients, including 16 males (35.6%) and 29 females (64.4%). Data were randomly segregated into an 80% training set and a 20% validation set via 100-fold Monte Carlo cross-validation. The variables included in this study were highly independent. The model achieved good predictive power for postoperative sepsis (AUC = 0.89, 87.8% sensitivity, 86.9% specificity, and 87.4% accuracy). The top 10 variables that contributed to the model prediction were preoperative midstream urine bacterial culture, sex, days of preoperative antibiotic use, urinary nitrite, preoperative blood white blood cell (WBC), renal pyogenesis, staghorn stones, history of ipsilateral urologic surgery, cumulative stone diameters, and renal anatomic malformation.

CONCLUSION

Our predictive model is suitable for sepsis estimation after PCNL and could effectively reduce the incidence of sepsis through early intervention.

Assessment of Pre-operative Factors Associated With Blood Loss in Patients Undergoing Percutaneous Nephrolithotomy: A Prospective Study

Background One of the main risks associated with percutaneous nephrolithotomy (PCNL) is bleeding. In the present study, efforts are made to evaluate the pre-operative predictive factors contributing to bleeding due to the procedure of PCNL. Materials and methods From December 2019 to November 2021, data were collected prospectively from 193 patients undergoing PCNL procedures at Indira Gandhi Institute of Medical Sciences, Patna, India. Following PCNL, to check for hematuria and the extent of blood loss, the urethral catheter's and nephrostomy tube's outputs were evaluated. Multivariate regression analysis was used to evaluate the relationship between blood loss and a variety of patient-related demographic and clinical characteristics. Results Included in the study were 193 patients who underwent PCNL. Male patients made up the majority. The average age of study participants was 33.5 years. No statistically significant difference was reported in the mean hemoglobin level drop in the age groups of up to 25 years (2.211 ± 1.540 g/dL), 26-50 years (2.023 ± 1.882 g/dL), and > 50 years (1.855 ± 0.986 g/dL) with P = 0.64. The mean hemoglobin level drop in patients with stone burden > 30 mm2 was reported to be higher, 2.359 ± 1.822 g/dL, compared to 1.859 ± 1.540 g/dL in patients with lower stone burden, reaching a statistically significant difference (P =0.0408). By univariate regression analysis, the presence of a horseshoe-shaped kidney (odds ratio = -0.158, 95% confidence interval (CI): -0.911, -0.059; P = 0.026) was associated with a higher risk for a drop in mean hemoglobin level. By multivariate regression analysis, the presence of a horseshoe-shaped kidney (odds ratio = 0.071, 95% CI: 0.006, 0.839; P = 0.036) remained significantly and independently associated with a higher risk of a drop in mean hemoglobin level. Conclusion In conclusion, the patients' burden of stones and the presence of a horseshoe-shaped kidney may be associated with a higher risk of bleeding following PCNL.

Comparative assessment of multiple-tract vs single-tract percutaneous nephrolithotomy

INTRODUCTION

To investigate the efficacy and safety of multi-tract percutaneous nephrolithotomy (PNL) against the benchmark of the single-tract approach.

METHODS

A retrospective analysis of 391 consecutive PNL procedures was conducted in our tertiary referral center between April 2016 and March 2020. Clinical outcome parameters such as stone-free rate, operation time, postoperative complications according to Clavien-Dindo, length of hospital stay and time to ipsilateral recurrence resulting in active treatment were assessed.

RESULTS

Multi-tract PNL and single-tract PNL were performed in 37 (9%) and 354 (91%) cases respectively. At baseline, compared to single-tract PNL, multi-tract PNL cases were characterized by significantly larger stone burden (2.62 vs 0.97 cm³ , P < .00), lower Hounsfield units (HU) (751 vs 1017 HU, P < .01), a more complex S.T.O.N.E. (size, tract length, obstruction, number of calyces, essence) score (P < .00) and a higher rate of high-risk stone formers (59 vs 19%, P < .00). Analysis of outcome revealed shorter operation time and length of hospital stay for single-tract PNL compared to multi-tract PNL (P < .01). However, the difference in terms of stone-free rates (92% vs 88%), complication rates (43% vs 28%) and time to active retreatment due to ipsilateral recurrence was not statistically significant (P > .05).

CONCLUSION

In this retrospective single-center analysis, a multi-tract PNL has been proved to be an efficient and safe expansion of single-tract PNL for large stone burden and complex kidney stone disease. Future prospective research should focus on the procedure's potential effectiveness in reducing the number of interventions until stone-free status in patients with massive stone disease.

Ultra-mini-percutaneous nephrolithotomy in flank-free modified supine position versus prone position in treatment of pediatric renal pelvic and lower calyceal stones

OBJECTIVES

To report the safety and efficacy of ultra-mini-percutaneous nephrolithotomy (UMPCNL) in flank free modified supine (FFMS) and prone positions in management of pediatric renal calculi.

PATIENTS & METHODS

This prospective randomized study included 55 pediatric patients with symptomatic renal stones and suitable for ultra-mini-percutaneous nephrolithotomy. They were randomized into two groups. Group A included 28 patients who were treated by UMPCNL in FFMS position (with a pad below the ipsilateral shoulder and buttocks, putting ipsilateral upper limb over the chest, and crossing the extended ipsilateral lower limb over the flexed contralateral one) and Group B included 27 patients treated by UMPCNL in the prone position. In both groups dilatation was done to 13 French sheath allowing the introduction of 6/7.5 French semi-rigid ureteroscope and fragmentation of stones by Ho:YAG laser with a 550-μm fiber laser lithotripter.

RESULTS

The operation time in FFMS position UMPCNL group was significantly shorter than prone position UMPCNL group (84.3±9.87 vs. 99.3±8.75) minutes with p=0.022. There was no significant difference between both groups in terms of stone free rate (89.3% vs. 88.9%), overall complication rate (including transient fever) (21.4% vs. 18.5%), post-operative pain (VAS score) (3.4±0.8 vs. 3.3±0.9), or hospital stay (3.53±0.8 vs. 4.1±1.1) days.

CONCLUSION

Both ultra-mini-percutaneous nephrolithotomy in FFMs and prone positions are feasible, safe and effective in treatment of pediatric renal stones with relatively shorter operative time in FFMS position.

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.

The role of ureteroscopy for treatment of staghorn calculi: A systematic review

Objective

To define the role of ureteroscopy for treatment of staghorn calculi.

Methods

A systematic review was conducted using the Scopus and Medline databases. Original articles and systematic reviews were selected according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only studies relating to the role of ureteroscopy for treatment of staghorn calculi were included.

Results

In five studies on ureteroscopic monotherapy, stone-free rate (SFR) ranged from 33% to 93%, with a maximum four ureteroscopy sessions per patient and no major complications. Endoscopic combined intrarenal surgery (ECIRS) was compared with percutaneous nephrolithotomy (PNL) in two studies and reached significantly higher SFR (88%-91% vs. 59%-65%) and lower operative times (84-110 min vs. 105-129 min). The role of salvage ureteroscopy for residual stones after primary PNL has been highlighted by two studies with a final SFR of 83%-89%. One study reported on the feasibility of ureteroscopy for ureteral stones and same-session PNL for contralateral staghorn calculi, with a SFR of 92%.

Conclusion

Ureteroscopy plays a pivotal role in the setting of a combined approach to staghorn calculi. Ureteroscopy is also particularly suitable for clearance of residual stones. In specific cases, ureteroscopy may become the sole applicable therapeutic option to staghorn calculi. Technological advances and refinement of techniques suggest a major role of ureteroscopy for staghorn calculi treatment in close future.

Comparison of Miniaturized Percutaneous Nephrolithotomy and Standard Percutaneous Nephrolithotomy in Secondary Patients: A Randomized Prospective Study

Aim: We aimed to compare the efficacy and safety of mini-percutaneous nephrolithotomy (mPNL) and standard PNL (sPNL) in a group of patients who had a history of PNL and/or open renal surgery (secondary patients). Materials and Methods: The study included 148 patients who underwent secondary PNL between November 2016 and September 2018. The patients with kidney stone ≥2 cm were included in the study. Patients were randomly divided into two groups as mPNL and sPNL. For both groups, demographic data, stone characteristics, and operative and postoperative data were recorded prospectively. Data were analyzed at 95% confidence interval and considered significant when p value was <0.05. Results: A total of 148 (76 mPNL, 72 sPNL) patients with a history of PNL and/or open surgery were included in the study. The mean duration of operation was longer in mPNL (106.9 vs 91.2 minutes, p = 0.016). The mean duration of fluoroscopy in mPNL was shorter (4.4 vs 5.3 minutes, p = 0.021). The tubeless procedure was higher in the mPNL (21.1% vs 2.8%, p = 0.001). The hemoglobin drop was less in mPNL (0.7 vs 1.4 g/dL, p = 0.011). Duration of nephrostomy and hospitalization was longer in sPNL (p = 0.001 and p = 0.005, respectively). The success rate in the mPNL group was higher compared with the sPNL group; however, this difference was statistically insignificant (75.0% vs 72.2%, p = 0.558). Conclusion: mPNL is superior to sPNL in terms of hemoglobin drop, duration of fluoroscopy, applicability of a tubeless procedure, and duration of nephrostomy and hospitalization among secondary patients. Duration of operation was found to be longer for mPNL. Success rate was higher in the mPNL group, although not statistically significant.

Retrograde intrarenal surgery and percutaneous nephrolithotomy for the treatment of stones in horseshoe kidney; what are the advantages and disadvantages compared to each other?

Introduction

Kidney stones occur more frequently in patients with a horseshoe kidney (HSK) anomaly. Abnormal anatomy may make the stone removal procedures more difficult. Therefore we aimed to evaluate and compare retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PCNL) for the treatment of renal stones in the HSK anomaly.

Material and methods

In this descriptive study, patients with HSK anomaly who underwent RIRS and PCNL procedures were retrospectively evaluated. Demographic and renal stone characteristics, success and complications associated with the surgical methods were compared across patients.

Results

A total of 49 patients were evaluated, 28 underwent RIRS and 21 underwent PCNL. No differences were determined between the groups concerning the demographics of patients and stone characteristics. A single session and final stone-free rate was 71.4% and 85.7% in RIRS, 81% and 90.5% in PCNL (both p ≥0.05). However, RIRS had more re-treatment rate, while its mean length of hospital stay was shorter than PCNL (p = 0.035, p = 0.001). While no differences were detected between the associated complication rates, more of the complications encountered in the PCNL group were of a serious nature.

Conclusions

In the HSK anomaly, renal stones can be treated with RIRS and PCNL procedures with high success. With its minimal morbidity, low complication rates and the minor character of the associated complications, the RIRS procedure can sometimes be preferred to avoid complications related to PCNL in HSK anomaly with big sized kidney stones.

Different managements of horseshoe kidney stones, any difference in the outcome?

Purpose

The aim is to assess the outcomes of different approaches for the management of renal stones associated with horseshoe kidneys (HSKs) in our institution over a 12-year period.

Methods

A retrospective review of 144 patients with HSKs who presented from 2000 to 2012 was performed. Twenty-eight patients (19.4%) were found to have renal stones. Demographic data were collected; the method of treatment and the outcomes of stone management were reviewed. We excluded patients with non-functioning moieties and associated genitourinary anomalies, and those with incomplete data.

Results

We included 25 patients, of which 16 males (64%) and 9 females (36%), with a mean age of 37 years. Mean serum creatinine level was 66 mmol/L. Eleven patients with a stone size <8 mm were treated expectantly with medical treatment, with only one patient requiring endoscopic intervention. Six patients (24%) with a stone size between 1 cm and ≤2 cm were treated with extracorporeal shock wave lithotripsy (ESWL) with the placement of double J stents, and seven patients (28%) with a stone size of >2 cm were treated with percutaneous nephrolithotomy. One patient with a 10 mm stone was treated using flexible ureteroscopy. No significant perioperative complications were encountered.

Conclusions

Indications, methods of treatment, and outcomes of management of stones associated with HSKs were comparable to those for stones associated with normal kidneys. Tailored approach based on stone size is highly recommended. ESWL accompanied with ureteric stenting is a promising strategy for the management of stones associated with HSKs in selected patients requiring intervention.

Percutaneous nephrolithotomy: technique

Percutaneous nephrolithotomy (PCNL) is considered to be the first line of treatment for large renal stones. Though PCNL comes with higher morbidity, its efficacy is unbeaten by other minimally invasive modalities. However, potential complications, such as bleeding, occur. Improved skills and modifications of the procedure may reduce the probability of adverse outcomes. This article discusses the current trends and standards in PCNL technique with special focus on all important steps as positioning, access, instruments, dilation, disintegration, and exit, including outcomes, complication management, and training modalities.

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.

Outcome of ureteroscopy for stone disease in patients with horseshoe kidney: Review of world literature

Introduction and Objectives:

The management of urolithiasis in patients with horseshoe kidney (HSK) is difficult. Stone formation occurred in 1:5 patients with HSK due to impaired urinary drainage and infections. Percutaneous nephrolithotomy and shock wave lithotripsy can be technically challenging due to altered anatomy.

Materials and Methods:

We conducted a systematic review of the literature to look at the role of ureteroscopy for stone management in these patients. We searched MEDLINE, PubMed and the Cochrane Library from January 1990 to April 2013 for results of ureteroscopy and stone treatment in HSK patients. Inclusion criteria were all English language articles reporting on ureteroscopy in patients with HSK. Data were extracted on the outcomes and complications.

Results:

A total of 3 studies was identified during this period. Forty-one patients with HSK underwent flexible ureteroscopy and stone treatment. The mean age was 42 with a male:female ratio nearly 3:1. The mean stone size was 16 mm (range: 3-35 mm). The mean operating time was 86 min with multiple stones seen in 15 patients. All 41 patients had a ureteral access sheath used and flexible ureteroscopy and holmium laser fragmentation done. Thirty-two (78%) patients were stone-free with a mean hospital stay of 1-day. Minor complications (Clavien I or II) were seen in 13 (32%) of which 6 had stent discomfort, 3 needed intravenous antibiotics for <24 h, 3 had hematuria of which 2 needed blood transfusion and one had pyelonephritis needing re-admission and antibiotics. There were no major complications found in the review.

Conclusions:

Retrograde stone treatment using ureteroscopy and lasertripsy in HSK patients can be performed with good stone clearance rate, but with a slightly higher complication rate. This procedure should, therefore, be done in high volume stone center with an experienced stone surgeon/team.

Recent advancement or less invasive treatment of percutaneous nephrolithotomy

Since its initial introduction in 1976, percutaneous nephrolithotomy (PCNL) has been widely performed for the management of large renal stones and currently is recommended for staghorn calculi, kidney stones larger than 2 cm, and shock wave lithotripsy-resistant lower pole stones greater than 1 cm. However, except for open and laparoscopic surgery, PCNL is the most invasive of the minimally invasive stone surgery techniques. Over the years, technical and instrumental advances have been made in PCNL to reduce morbidity and improve effectiveness. A thorough review of the recent literature identified five major areas of progress for the advancement of PCNL: patient positioning, method of percutaneous access, development of lithotriptors, miniaturized access tracts, and postoperative nephrostomy tube management. This review provides an overview of recent advancements in PCNL and the outcomes of each area of progress and notes how much we achieve with less invasive PCNL. This information may allow us to consider the future role and future developments of PCNL.

Lumbar plexopathy as a complication of percutaneous nephrolithotomy in a horseshoe kidney

Treatment of nephrolithiasis in horseshoe kidneys can be challenging due to anomalies in renal position, collecting system anatomy and vascular supply. We report on a patient who was referred after a failed percutaneous nephrolithotomy for a left moiety staghorn calculus in a horseshoe kidney. Two punctures had been performed involving upper and middle posterior calyces. Both were very medially placed and inadvertently traversed the psoas muscle, resulting in lumbar plexopathy with permanent deficit. This complication presented postoperatively with left leg weakness, paresthesia, and pain which impaired independent ambulation. The patient went on to be successfully treated for her stone disease with robotic-assisted laparoscopic pyelolithotomy.

Risk factors for sepsis after percutaneous renal stone surgery

Since its introduction into the endourologist's armamentarium almost 40 years ago, percutaneous nephrolithotomy (PCNL) has become the standard of care for patients with large-volume nephrolithiasis. Postoperative infection is one of the most common complications of the procedure, and postoperative sepsis is one of the most detrimental. A number of factors have been found to increase the risk of postoperative sepsis. These include patient characteristics that are known preoperatively, such as urine culture obtained from the bladder or from the renal pelvis if percutaneous access to the renal pelvis is obtained in advance to the procedure. Neurogenic bladder dysfunction secondary to spinal cord injury and anatomical renal abnormalities, such as pelvicalyceal dilatation, have also been associated with increased incidence of fever and sepsis after the procedure. Several intraoperative factors, such as the average renal pressure sustained during PCNL and the operative time, also seem to increase the risk of sepsis. Finally, the contribution of postoperative factors, such as presence of a nephrostomy tube or a urethral catheter, has also been investigated. A short preoperative course of antibiotics has been found to significantly decrease the rate of postoperative fever and sepsis. Novel agents targeted at sepsis prevention and treatment, such as anti-endotoxin antibodies and cholesterol-lowering drugs statins, are currently under investigation.

Predictive factors for bleeding during percutaneous nephrolithotomy

Purpose

Although percutaneous nephrolithotomy (PCNL) has been accepted as a standard method for the management of large renal stones, the incidence of renal hemorrhage is relatively high. This study investigated the variables that affect bleeding during PCNL.

Materials and Methods

The medical records of 370 patients who underwent PCNL by a single surgeon from January 2005 to December 2010 were reviewed retrospectively. All patients were divided into two groups according to median blood loss (lesser bleeding group and higher bleeding group). Various clinical and perioperative factors including age, sex, stone size and position, degree of hydronephrosis, operative time, underlying disease, history of anticoagulant medication, presence of previous nephrostomy catheter, stone composition, and thickness of the renal cortex were assessed. For statistical assessment, univariate and multivariate logistic regression analyses were used.

Results

The mean patient age was 48.8 years (range, 22 to 75 years). Forty-three patients (11.6%) received a transfusion and 9 patients (2.4%) underwent angioembolization after surgery. The mean blood loss was 511.8±341.3 mL. Body mass index (BMI), stone size, stone position, operation time, and degree of preoperative hydronephrosis were predictive factors for severe bleeding during PCNL.

Conclusions

On the basis of the results achieved by a single surgeon, staghorn stones, high BMI, large stones, prolonged operation time, and absence of hydronephrosis were significantly associated with the risk of severe bleeding during PCNL.

Retrograde intrarenal surgery in patients with horseshoe kidneys

Retrograde intrarenal surgery (RIRS) in patients with horseshoe kidneys (HSKs) remains poorly studied. The present study aimed to assess clinical success and stone-free rates in HSK patients with renal stones treated with flexible ureteroscopy. RIRS was attempted in 20 patients with 25 renal stones in HSK from December 2008 to January 2012. The patients were evaluated with imaging studies including plain abdominal radiography, intravenous urogram, abdominal ultrasonography or non-contrast tomography scan. Success rate was defined as stone-free or residual fragment less than 4 mm. Pre-operative, operative and postoperative data were retrospectively analyzed. A total of 20 patients were included in the present study (12 males, 8 females). 9 of 25 renal stones (36 %) were located in the lower calyx of the kidney, whereas 7 (28 %) in the middle calyx, 5 (20 %) in the renal pelvis and 4 (16 %) in the upper calyx. The mean stone size was 17.8 ± 4.5 mm. The stone-free rate was 70 % after a single procedure. 6 patients required shock wave lithotripsy and two of these were completely stone-free. Average hospital stay was 1.4 ± 0.7 days. Minor complications as classified by Clavien I or II occurred in 25 %. No major complications (Clavien III-V) occurred in the study group. RIRS is an effective and safe treatment modality for renal stones in patients with HSK. The procedure has minimal morbidity and high success rate.

Blood transfusion, embolisation and nephrectomy after percutaneous nephrolithotomy (PCNL)

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Percutaneous treatment for renal stone disease is associated with a risk of significant morbidity. Our large UK series provides contemporary data on the risk of vascular complications and admission to the Intensive Care Unit (ICU) after PCNL. When compared with recent international databases, these data support the current evidence that better outcomes can be achieved in centres performing large numbers of procedures. These data add to the debate for the centralisation of specialist stone surgery.

OBJECTIVE

To audit the outcome of percutaneous nephrolithotomy (PCNL) at a UK stone centre over a 10-year period, and provide patients with understandable contemporary data on blood loss and vascular risk.

PATIENTS AND METHODS

A single centre retrospective analysis of all PCNLs undertaken between April 2000 and December 2010. The association between transfusion and patient age, operative duration and positive preoperative mid-stream urine (MSU) sample was subject to statistical analysis.

RESULTS

Data on 568 patients was analysed. 21 were paediatric cases with a mean (range) age of 8 (2-16) years; 547 were adult cases with a mean (range) age of 55 (17-84) years. 3.8% of adult patients (21/547) received a blood transfusion; mean age 60 years (55 years in those not transfused) with a mean operative duration of 119 min (103 min in those not transfused). 23.8% of patients transfused had a confirmed preoperative urinary tract infection compared with 16.1% of those not transfused. Seven patients underwent angiography, with five having selective arterial embolisation (0.9%). There were no deaths in this series although one patient (0.2%) required an urgent nephrectomy due to cardiovascular instability from bleeding.

CONCLUSIONS

Large UK series that provides contemporary data for consent on vascular risk at PCNL. The risk of transfusion is associated with increased patient age, operative duration and the presence of a positive preoperative MSU sample. Data compares favourably with other large published series, and supports the argument for centralisation of percutaneous stone management.

[Surgical therapy of lithiasis in horseshoe kidney]

OBJECTIVE

To present our centre's experience in the surgical treatment of lithiasis in patients with horseshoe kidney.

MATERIAL AND METHODS

From October 2007 to March 2011 we treated 10 patients with renal lithiasis in their horseshoe kidneys. Retrospectively, we reviewed the symptoms, medical and surgical history, the characteristics of the stones (size, location, composition) and treatments that were carried out. In all the cases, the study was carried out by CT, with volume reconstruction and with an angiographic study. A percutaneous nephrolithotomy (PCNL) or an endoscopic retrograde intrarrenal surgery (RIRS) was carried out, depending on the size and location of the stone.

RESULTS

Three percutaneous nephrolithotomies were carried out (2 on staghorn lithiasis stones, 1 pseudocoraliform stone) with a combined rigid and flexible single-access nephroscopy. In one case there was haemorrhage that required treatment by selective embolization. In the rest, RIRS was carried out, all with stones < 30 mm in their greatest diameter without any complications. The mean surgical times were 120 (60-180) minutes for the percutaneous route and of 105 (65-160) minutes for the retrograde route. In all the cases the treatment achieved a complete elimination of the stones or remains of less than 5 mm.

CONCLUSIONS

The treatment of renal lithiasis in horseshoe kidneys is complex, given their peculiar anatomy. The usual surgical techniques can be reproduced in these cases with good results. We opt for PCNL in complete staghorn stone and pseudocoraiform stones, whereas RIRS is a valid option in cases with stones < 3 cm.

Stereotactic localisation system: a modified puncture technique for percutaneous nephrolithotomy

The objective of the study was to establish and evaluate a modified puncture and dilation technique-"stereotaxic localisation" system-and the corresponding instruments for percutaneous nephrostomy. Four hundred patients were randomised to the intervention group (200 cases, stereotaxic location puncture and dilation procedures) and the traditional group (200 cases, traditional procedure) under X-ray guidance. In the modified intervention system, the distance and horizontal angle of the puncture pathway between the puncture point and the target site were calculated accurately. The time for punctures, time with X-ray exposure and operation, success rate of each puncture to access the target, number of patients requiring blood transfusion, stone clearance, drops of haemoglobin and days of hospital stay were compared between the two groups. In the traditional and intervention groups, the time for puncture was 17 and 7 min, respectively; the X-ray exposure time was 9.1 and 1.3 min; the cases requiring blood transfusion were 9 and 5; and the success rates for each puncture to access the target were 42.9 and 88.0%, all with statistical difference (p < 0.01). The other outcomes and complications revealed similar trends. The stereotaxic localisation system for puncture is statistically better than the traditional procedure used in this study. The stereotaxic localisation system in this study is safer and more accurate, and provides easier access to the target with less bleeding and reduced exposure to X-ray compared to the traditional puncture and dilation procedures of percutaneous nephrostomy.

Incidence, prevention, and management of complications following percutaneous nephrolitholapaxy

CONTEXT

Incidence, prevention, and management of complications of percutaneous nephrolitholapaxy (PNL) still lack consensus.

OBJECTIVE

To review the epidemiology of complications and their prevention and management.

EVIDENCE ACQUISITION

A literature review was performed using the PubMed database between 2001 and May 1, 2011, restricted to human species, adults, and the English language. The Medline search used a strategy including medical subject headings (MeSH) and free-text protocols with the keywords percutaneous, nephrolithotomy, PCNL, PNL, urolithiasis, complications, and Clavien, and the MeSH terms nephrostomy, percutaneous/adverse effects, and intraoperative complications or postoperative complications.

EVIDENCE SYNTHESIS

Assessing the epidemiology of complications is difficult because definitions of complications and their management still lack consensus. For a reproducible quality assessment, data should be obtained in a standardized manner, allowing for comparison. An approach is the validated Dindo-modified Clavien system, which was originally reported by seven studies. No deviation from the normal postoperative course (Clavien 0) was observed in 76.7% of PNL procedures. Including deviations from the normal postoperative course without the need for pharmacologic treatment or interventions (Clavien 1) would add up to 88.1%. Clavien 2 complications including blood transfusion and parenteral nutrition occurred in 7%; Clavien 3 complications requiring intervention in 4.1.%; Clavien 4, life-threatening complications, in 0.6%; and Clavien 5, mortality, in 0.04%. High-quality data on complication management of rare but potentially debilitating complications are scarce and consist mainly of case reports.

CONCLUSIONS

Complications after PNL can be kept to a minimum in experienced hands with the development of new techniques and improved technology. A modified procedure-specific Clavien classification should be established that would need to be validated in prospective trials.

Percutaneous nephrolithotomy in horseshoe kidneys: factors affecting stone-free rate

PURPOSE

We report a 2-center study of factors affecting the stone-free rate after percutaneous nephrolithotomy in horseshoe kidneys.

MATERIALS AND METHODS

The postoperative stone-free rate after percutaneous nephrolithotomy was evaluated in 47 male and 11 female patients with horseshoe kidneys. All data were collected prospectively. Patient and procedure related factors predicting the stone-free rate were analyzed by univariate and multivariate tests.

RESULTS

The mean ± SD stone burden was 7.62 ± 7.18 cm(2) (range 1 to 45) and the stone was larger than 10 cm(2) in 14 patients (24.1%). Complex stones and staghorn stones were present in 21 (36.2%) and 19 patients (32.7%), respectively. The overall stone-free rate was 65.5%. Complex stones (p = 0.01), stone burden greater than 5 cm(2) (p = 0.013), stone burden greater than 10 cm(2) (p = 0.012), multiple stones (p = 0.006) and staghorn stones (p <0.001) were related to adverse outcomes on univariate analysis. Logistic regression analysis revealed that staghorn calculi was the only factor that significantly predicted the stone-free rate (p = 0.002). A patient with staghorn calculi in the horseshoe kidney was 45 times more likely to have a lower stone-free rate after percutaneous nephrolithotomy than a patient without staghorn calculi in the horseshoe kidney.

CONCLUSIONS

Stone parameters are important when treating calculi in horseshoe kidneys. Staghorn calculi are associated with a lower stone-free rate after percutaneous nephrolithotomy.