Two contemporary series of percutaneous tract dilation for percutaneous nephrolithotomy

Navigation systems and 3D imaging in percutaneous nephrolithotripsy: improving outcomes and safety

PURPOSE OF REVIEW

Percutaneous nephrolithotripsy (PCNL) is the first-line management option for large kidney stones (>2 cm). It remains, however, a demanding procedure with considerable morbidity. The present narrative review summarizes recent knowledge from original research studies investigating navigation systems/three-dimensional (3D) imaging in PCNL, particularly on publications during the past 12-18 months.

RECENT FINDINGS

Navigation systems and 3D imaging are primarily used for preoperative planning, with few intra-operative applications. Patient management and residents' training could benefit from their use.

SUMMARY

Navigation systems and 3D imaging technology have emerged as a potential game-changer in PCNL. Even though available evidence is currently scarce/inconclusive, the safety/efficacy of navigation systems and 3D dimensional imaging use in PCNL appears promising. This advanced technology offers precise anatomical mapping, improved visualization, and surgical accuracy. Enabling a comprehensive preoperative evaluation and improving guidance, navigation systems, and 3D imaging technology may improve the safety and efficacy of PCNL. With continuous technological evolution, it is expected that improvements/innovations will offer further aid in such demanding procedures. Familiarization and cost reduction are necessary for widespread application, while larger-scale prospective studies and well designed randomized controlled trials are still needed.

Assessment of Three-Dimensional Reconstruction in Percutaneous Nephrolithotomy for Complex Renal Calculi Treatment

Introduction: Three-dimensional (3D) reconstruction is a novel imaging technique widely used to improve surgical operations. Some studies have identified its role in Urology for percutaneous nephrolithotomy (PCNL).

Objective: To explore the potential benefits of 3D reconstruction technology in PCNL for complex renal calculi treatment.

Methods: A retrospective study involving 139 patients with complex kidney stones who underwent PCNL was conducted between September 30, 2018, to September 30, 2019. Group A patients (72) underwent the 3D reconstruction technique before PCNL, while group B (67) did not. The operation time, the duration of the hospital stay, the puncture accuracy, the decrease in hemoglobin concentration, the stone clearance rate, and the postoperative complications were noted and compared between the two groups.

Results: The initial stone clearance rates 2 weeks after PCNL were 81.9 and 64.2% in groups A and B, respectively (P < 0.05). The first-time puncture success rates were 87.5 and 47.8 % in groups A and B, respectively (P < 0.05). Group A had a shorter operation time than group B (62 vs. 79 min, P < 0.05). Besides, the 3D reconstructive technique-assisted patients (91.7%) had no or mild complications, compared with (74.6%) group B patients. There was no significant difference in hemoglobin decline and hospital stay between the two groups.

Conclusions: The 3D reconstruction technology is an effective adjunct to PCNL in the complex renal calculi treatment.

A randomized study comparing conventional percutaneous nephrolithotomy versus check pyeloscopic percutaneous nephrolithotomy

Objective

The objective of this study is to compare the advantages of check-pyeloscopic percutaneous nephrolithotomy (CP-PCNL) over conventional PCNL (C-PCNL) in the management of renal calculi.

Materials and Methods

All patients with renal calculi requiring PCNL who attended the department of urology in a tertiary care center from December 2016 to October 2018 were included in the study. The patients were randomized into two groups of 50 each. Each group underwent PCNL in a conventional or check pyeloscopic method, respectively.

Results

A total number of complications were more in C-PCNL group comprising of two pelvic tears, 8 infundibular tears, 1 minor urothelial injury, 2 cases of bleeding lasting for more than 24 hours, while in CP-PCNL group, complications were less (comprising of 1 minor urothelial injury and 1 case of infundibular tear). Statistical analysis was used to compare both the groups, and the results were statistically significant (P = 0.027).

Conclusion

Check pyeloscopy at the time of PCNL is a safe, effective, and economical technique. This study shows that the complications such as blood loss, urothelial injury, and postoperative pain are less when check pyeloscopy is done during PCNL.

The Pros and cons of balloon dilation in totally ultrasound-guided percutaneous Nephrolithotomy

Background

To evaluate the feasibility and safety of balloon dilation (BD) in totally ultrasound-guided percutaneous nephrolithotomy (PCNL).

Methods

The data of 95 patients underwent BD were collected in this retrospective study between August 2016 and December 2018. During the same period, telescopic metal dilation was used in 1161 patients. Ninety five patients were selected as the control group and matched at a 1:1 ratio to index balloon dilation (BD) cases in regards to Guy’s stone score, age, sex, BMI, degree of hydronephrosis and stone area. Peri-operative data were compared between the two groups.

Results

Total operative time was significantly shorter in the BD group (62.2 ± 22.4 min vs. 70.2 ± 25.8 min, p = 0.024). Tract establishment time was significantly shorter in the BD group (3.4 ± 1.8 min vs. 4.3 ± 2.3 min, p < 0.001). The success rate of tract dilation by first attempt was higher in the TMD group compared with that of BD group; however the difference was not statistically significant. There was no significant difference between groups with regards to complication and stone-free rates. The cost of PCNL in the BD group was significantly higher than that of the TMD group (US $4831.4 ± 1114.8 vs. US $4328.4 ± 975.7, p = 0.012). Subsequent analysis revealed that mild or no hydronephrosis were risk factor for failure of balloon dilation under ultrasound.

Conclusions

BD has acceptable complication and stone free rates compared with those in TMD; however, BD under ultrasound is not suggested for stone cases without hydronephrosis.

Anatomic and Radiologic Study of Renal Avascular Plane (Brödel's Line) and Its Potential Relevance on Percutaneous and Surgical Approaches to the Kidney

OBJECTIVE

The aim of the present anatomic and radiologic study was to evaluate the location, extension, and characteristics of the Brödel's plane and eventually define its different patterns.

MATERIALS AND METHODS

We evaluated 15 human normal kidneys sampled from unembalmed cadavers without clinical history or anatomical evidence of renal diseases. Kidneys with the surrounding perirenal fat tissue were removed en bloc with the abdominal segment of the aorta. The renal artery was injected with acrylic and radiopaque resins. A CT examination of the injected kidneys was performed. After the imaging acquisition, the specimens were treated with sodium hydroxide for removal of the parenchyma to obtain the vascular casts. All the CT images were elaborated using dedicated three-dimensional (3D) software with the aim to improve the possibility to identify the Brödel's plane. The avascular plane was identified directly on the vascular casts and confirmed on the corresponding 3D images.

RESULTS

The avascular plane was located in all cases medially to the lateral convex border of the kidneys. The recorded mean distance was 2.04 cm (range 1.8-2.4 cm). Three patterns of distribution of the Brödel's line were identified. In five (33.3%) cases the avascular plane was extended from the apical to the inferior segment of the kidneys (type 1); in six (40%) from the superior to the inferior segment (type 2); and in four (26.7%) from the apical to the middle segment (type 3). Fourth and fifth order vessels crossing the Brödel's line were detected in all the analyzed cases.

CONCLUSIONS

The renal avascular plane showed a different extension allowing us to cluster three different patterns. Preoperative identification of the Brödel's line patterns could help surgeons to minimize hemorrhagic complications during percutaneous and surgical procedures requiring an incision of the renal parenchyma such as traditional or robot-assisted nephrolithotomy or partial nephrectomy for endophytic renal tumors. Radiologic studies validated that the described patterns in the clinical practice are strongly needed.

Renal parenchyma injury after percutaneous nephrolithotomy tract dilatations in pig and cadaveric kidney models

Introduction

Miniaturization of instruments has changed the paradigms of percutaneous nephrolithotomy (PCNL). To date, however, few studies have analyzed the possible renal trauma generated by PCNL tract dilation. The purpose of this study is to evaluate and compare systematically the renal injury of all PNCL dilation techniques in pork kidneys (PK) and cadaveric kidney models (CK).

Material and methods

Twelve dilation devices were tested (from 4.8 to 30 French (Fr)) including micro- and mini- PCNL kits, the Alken dilation set, 20 and 30 ATM balloons and the Amplatz set. Each device was tested six times in PK and CK. Morphologic analysis of tract defects of the different models and dilators were made measuring the longest axis and the area of renal parenchymal damage.

Results

When comparing the PK and CK dilation tract areas to the device areas, major differences were seen with the 20 ATM 30 Fr balloon (p = 0.0001 and 0.008) respectively, the sequential Amplatz dilation to 30 Fr (p = 0.0005 and 0.0006) respectively, and the Alken 30 FR dilation (p = 0.012 and 0.02) respectively. The 30 Fr dilations were 32.76 mm² (mean) larger than the instruments themselves, while the ≤24 Fr dilations were 11.6 mm² (mean) larger than the instruments themselves.

Conclusions

When comparing devices and tract areas, the dilation tract area exceeded device area by 11.6 mm² at dilations up to 24 Fr vs. 32.76 mm² with dilations of 30 Fr. Overall, PK had significantly larger injuries than CK models.

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.

EAU Guidelines on Interventional Treatment for Urolithiasis

CONTEXT

Management of urinary stones is a major issue for most urologists. Treatment modalities are minimally invasive and include extracorporeal shockwave lithotripsy (SWL), ureteroscopy (URS), and percutaneous nephrolithotomy (PNL). Technological advances and changing treatment patterns have had an impact on current treatment recommendations, which have clearly shifted towards endourologic procedures. These guidelines describe recent recommendations on treatment indications and the choice of modality for ureteral and renal calculi.

OBJECTIVE

To evaluate the optimal measures for treatment of urinary stone disease.

EVIDENCE ACQUISITION

Several databases were searched to identify studies on interventional treatment of urolithiasis, with special attention to the level of evidence.

EVIDENCE SYNTHESIS

Treatment decisions are made individually according to stone size, location, and (if known) composition, as well as patient preference and local expertise. Treatment recommendations have shifted to endourologic procedures such as URS and PNL, and SWL has lost its place as the first-line modality for many indications despite its proven efficacy. Open and laparoscopic techniques are restricted to limited indications. Best clinical practice standards have been established for all treatments, making all options minimally invasive with low complication rates.

CONCLUSION

Active treatment of urolithiasis is currently a minimally invasive intervention, with preference for endourologic techniques.

PATIENT SUMMARY

For active removal of stones from the kidney or ureter, technological advances have made it possible to use less invasive surgical techniques. These interventions are safe and are generally associated with shorter recovery times and less discomfort for the patient.

Fluoroscopy guided percutaneous renal access in prone position

Percutaneous nephrolithotomy is a very commonly done procedure for management of renal calculus disease. Establishing a good access is the first and probably the most crucial step of this procedure. A proper access is the gateway to success. However, this crucial step has the steepest learning curve for, in a fluoroscopy guided access, it involves visualizing a three dimensional anatomy on a two dimensional fluoroscopy screen. This review describes the anatomical basis of the renal access. It provides a literature review of all aspects of percutaneous renal access along with the advances that have taken place in this field over the years. The article describes a technique to determine the site of skin puncture, the angle and depth of puncture using a simple mathematical principle. It also reviews the common problems faced during the process of puncture and dilatation and describes the ways to overcome them. The aim of this article is to provide the reader a step by step guide for percutaneous renal access.

Lessons learned from the CROES percutaneous nephrolithotomy global study

PURPOSE

The purpose of the study was to give an overview of the data derived from the CROES PCNL Global Study published previously in 25 articles.

METHODS

A comprehensive overview of the outcome of the CROES PCNL Global Study was made, analysed and compared with the current literature and guidelines.

RESULTS

Percutaneous nephrolithotomy (PCNL) was predominately performed in prone position. Although the supine position claims to be favourable over the prone approach, the present study showed a longer operation time and lower stone-free rate (SFR). This might be explained by differences in definition in operation time and methods in the evaluation of residual stones. Ultrasound (US)-guided access proves beneficial in lowering puncture time and radiation exposure. Renal anomalies can safely be treated by PCNL and have similar outcomes to a normal situation. In patients with a solitary kidney, however, there is a lower SFR and more bleeding. Also, severe chronic kidney disease (CKD) patients have less favourable outcome. Morbidity and complications following PCNL are dominated by fever (10.5%) and bleeding (7.8%). A matched control analysis confirmed that antibiotic prophylaxis gives a threefold lower post-operative fever rate. In a multivariate analysis, it was elegantly demonstrated that bleeding was directly related to the size of the dilatation: the larger the bore, the higher the chance for bleeding. Elderly patients are at higher risk of complications and longer hospital stay. Overall, obese patients have similar outcome as the general population; however, super-obese (BMI > 40) patients have a higher chance of more severe complications. For the first time, this database illustrated a significant relationship between results and complications of PCNL, and caseload volume. The optimal case volume per centre appears to be 120 PCNL's/year. Finally, a nomogram has been developed that enables better patient counselling and decision-making.

CONCLUSION

The CROES PCNL Global Study is the largest real-life study providing new insights into general and special conditions. Because of the vast number of patients included, rare conditions including renal anomalies, solitary kidneys and patient characteristics like severe CKD, super obesity and old age could be analysed. Besides this information, a nomogram was developed. And for the first time, the influence of caseload volume was established.

[Complications in percutaneous lithotomy]

BACKGROUND

Percutaneous lithotomy is the gold standard in the treatment of large kidney stones. Several steps of the operation might cause severe complications. Safe procedures depend on careful planning, accurate performance, recognition of problems and knowledge of how to handle them.

OBJECTIVES

Relevant steps of percutaneous stone treatment with possible complications and their management are presented.

MATERIALS AND METHODS

Current topics in percutaneous stone treatment taking into consideration the relevant literature are discussed. Furthermore, rare complications and strategies for safe management are presented.

RESULTS

Careful planning and adequate preoperative diagnostic workup are essential for safe procedures. Puncture of the renal calyceal system and tract dilation might lead to severe complications. Bleeding and infectious complications are the most common problems. Availability of interventional radiology provides ideal emergency treatment in case of severe bleeding and helps to avoid surgical revision with high risk of organ loss.

CONCLUSIONS

Percutaneous stone treatment is a safe and effective therapy in an experienced physician's hands. Careful planning and accurate performance help to avoid severe complications.

Application of the modified clavien classification system to 402 cases of holmium laser enucleation of the prostate for benign prostatic hyperplasia

PURPOSE

We attempted to evaluate the perioperative complications of holmium laser enucleation of the prostate (HoLEP) for benign prostatic hyperplasia by using the modified Clavien classification system (MCCS).

MATERIALS AND METHODS

Targeting 402 patients who underwent HoLEP for benign prostatic hyperplasia performed by a single surgeon between July 2008 and January 2011, we investigated complications that occurred during and within 1 month after surgery and classified them into grade I to grade V on the basis of the MCCS. If two or more complications occurred in one patient, each complication was graded and counted.

RESULTS

The mean age, prostate volume, operation time, hospital stay, and average follow-up period of 402 patients who underwent HoLEP were 68.8 years (range, 52-84 years), 53.2 g (range, 23-228 g), 58.2 minutes (range, 20-230 minutes), 4.5 days (range, 2-7 days), and 9 months (range, 4-27 months), respectively; 78 complications occurred in 71 of the patients (morbidity rate, 17.6%). In MCCS grade I, complications occurred in 54 cases (69.2%); in grade II, complications occurred in 19 cases (24.3%); in grade III, complications occurred in 4 cases (5.1%); and in grade IV, 1 patient required intensive care unit care because of cerebral infarction (1.2%). There were no grade V complications.

CONCLUSIONS

The HoLEP-based MCCS complications classification was performed very quickly. However, MCCS, when compared with other measures of endoscopic prostate surgery experiences, including HoLEP, exposed the lack of accuracy in low grade classification and the inability to include late complications.

A comparison of balloon and amplatz dilators in percutaneous nephrolithotomy: a retrospective evaluation

OBJECTIVE

In this study, we compared our experience using balloon and amplatz dilatation in percutaneous nephrolithotomy (PCNL). We also evaluated peri- and postoperative variables, including success rates.

MATERIAL AND METHODS

Two hundred renal stone patients (123 men/77 women) underwent PCNL at the Urology Clinic of İzmir Atatürk Training and Research Hospital from September 2005 to May 2011. The nephrostomy tract was dilated using a balloon (128 patients) or amplatz (72 patients) dilator. The groups were compared by age, total operating time, treatment success rate, retreatment rate, pre- and postoperative hematocrit values, mean decrease in hematocrit values, blood transfusion rate, stone burden, tract dilatation failure, hospital stay and nephrostomy removal times, stone localization, previous stone operation and the cost of the dilatation system.

RESULTS

There was no statistically significant difference in the operative time (97.9±45.3 minutes in balloon group vs. 98.5±43.4 minutes in the amplatz group; p=0.43), preoperative hematocrit value (39.04±4.21 vs. 38.94±4.49; p=0.87), postoperative hematocrit value (32.74±4.86 vs. 32.48±5.43; p=0.73), decrease in hematocrit values (6.30±2.60 vs. 6.45±2.64; p=0.68), blood transfusion rate (15.6% vs. 16.7%; p=0.84) or treatment success rate (78.9% vs. 79.2%; p=0.96) between balloon and amplatz groups. Differences in other variables were also not observed between the two groups.

CONCLUSION

The balloon or amplatz dilatation methods have similar results with regard to efficacy, speed, and safety. However, the cost of the balloon dilator is higher than that of the amplatz dilator.

Analysis of the factors affecting blood loss in percutaneous nephrolithotomy: a registry of the Spanish Association of Urology in the supine position

OBJECTIVE

Percutaneous nephrolithotomy (PCNL) is the minimally invasive procedure of choice for removing renal stones larger than 2 cm. This study has aimed to identify the different variables that might influence decrease of hemoglobin during the surgery performed in supine position.

MATERIAL AND METHODS

A prospective, multicenter, observational study of supine PCNL, based on the Spanish Association of Urology database, was analyzed. The different preoperative and postoperative factors that might affect the decrease of hemoglobin were assessed: demographics and anthropometric data, comorbidities, size and location of the stones, anatomical variants and technical aspects of the procedure.

RESULTS

From September 2008 to December 2012, 397 supine PCNL procedures performed in 15 Spanish centers were registered. Mean hemoglobin decrease was 2.3±1.5 g/dl and overall blood transfusion rate was 5.5%. No statistically significant differences were found between genders, body mass index (BMI) and age in terms of blood loss. There were also no differences between patients with cardiovascular, hypertensive, diabetic and anticoagulant treatment background. Blood loss was not significantly influenced by stone size and location. Technical aspects of the procedure as operative time (> 120 min ≤), access to the pelvi-caliceal system (ultrasound, fluoroscopy), percutaneous tract dilation technique (Alken, balloon or Amplatz) or placement of nephrostomy (tube versus tubeless) were not associated with differences in pre-op/post-op hemoglobin. Only multiple percutaneous tracts (≥2) and middle calix access were statistically significantly (P=.03 and P=.01) related with less blood loss.

CONCLUSIONS

PCNL in supine position is a minimally invasive procedure for removal of large (≥2 cm) and multiple renal stones, with a low incidence of blood loss and minimal transfusion rate. Multiple percutaneous tracts and middle calix puncture were the only statistically significant variables associated with decrease in hemoglobin levels.

A comparison among four tract dilation methods of percutaneous nephrolithotomy: a systematic review and meta-analysis

The purpose of this study was to evaluate the efficacy and safety of the Amplatz dilation (AD), metal telescopic dilation (MTD), balloon dilation (BD), and one-shot dilation (OSD) methods for tract dilation during percutaneous nephrolithotomy (PCNL). Relevant eligible studies were identified using three electronic databases (Medline, EMBASE, and Cochrane CENTRAL). Database acquisition and quality evaluation were independently performed by two reviewers. Efficacy (stone-free rate, surgical duration, and tract dilatation fluoroscopy time) and safety (transfusion rate and hemoglobin decrease) were evaluated using Review Manager 5.2. Four randomized controlled trials and eight clinical controlled trials involving 6,820 patients met the inclusion criteria. The pooled result from a meta-analysis showed statistically significant differences in tract dilatation fluoroscopy time and hemoglobin decrease between the OSD and MTD groups, which showed comparable stone-free and transfusion rates. Significant differences in transfusion rate were found between the BD and MTD groups. Among patients without previous open renal surgery, those who underwent BD exhibited a lower blood transfusion rate and a shorter surgical duration compared with those who underwent AD. The OSD technique is safer and more efficient than the MTD technique for tract dilation during PCNL, particularly in patients with previous open renal surgery, resulting in a shorter tract dilatation fluoroscopy time and a lesser decrease in hemoglobin. The efficacy and safety of BD are better than AD in patients without previous open renal surgery. The OSD technique should be considered for most patients who undergo PCNL therapy.

Application of the Modified Clavien Classification System to 120W Greenlight High-Performance System Photoselective Vaporization of the Prostate for Benign Prostatic Hyperplasia: Is It Useful for Less-Invasive Procedures?

Purpose

To evaluate the accuracy and applicability of the modified Clavien classification system (CCS) in evaluating complications following photoselective vaporization of the prostate by use of the 120W GreenLight high-performance system (HPS-PVP).

Materials and Methods

The medical records of 342 men who underwent HPS-PVP were retrospectively analyzed. Patients were older than 40 years and had a prostate volume >30 mL and an International Prostate Symptom Score (IPSS) ≥8. Patients with prostatic malignancy, neurogenic bladder, urethral stricture, large postvoid residual volume (>250 mL), previous prostatic surgery, or urinary tract infection were excluded. All operations were done by a single surgeon, and patients were followed up for uroflowmetry and IPSS postoperatively. All complications were recorded and classified according to the modified CCS, and methods of management were also recorded.

Results

The patients' mean age was 71.6±7.3 years; mean prostate volume was 50.0±17.0 mL, and 95 cases (27.7%) had volumes greater than 70 mL. The mean total IPSS was 21.7±7.9 preoperatively and 12.3±8.1 at the first month postoperatively. A total of 59 patients (17.3%) experienced postoperative complications until the first month after the surgery. Among them, 49 patients (14.3%) showed grade I complications, 9 patients (2.6%) showed grade II complications, and 1 patient (0.3%) showed a grade IIIb complication. No patients had complications graded higher than IIIb.

Conclusions

Although the modified CCS is a useful tool for communication among clinicians in allowing comparison of surgical outcomes, this classification should be revised to gain higher accuracy and applicability in the evaluation of postoperative complications of HPS-PVP.

The "visual dilator system": initial experimental evaluation of an optical tract dilation technique in percutaneous nephrolithotomy

BACKGROUND AND PURPOSE

Ascertaining the optimal depth of dilator progression is a crucial factor during tract dilation in percutaneous nephrolithotomy. Dilation is generally guided under fluoroscopy, ultrasonography, or combination of both techniques, and it is still difficult to prevent overdilation causing perforation and vascular injury or underdilation causing difficulty in establishment of access. Thus, improvements in dilation technique bears clinical significance. Our aim was to evaluate the feasibility in an animal model of using the "visual dilator system" for optimal percutaneous tract dilation under real-time visual guidance.

MATERIALS AND METHODS

The visual dilator system consisted of a transparent hollow dilator made of polyvinyl chloride and a rigid ureteroscope inserted within its lumen. The ureteroscope was connected to a standard endoscopic camera system. The dilator system backloaded with an access sheath was passed over a guidewire to dilate the tract and position the access sheath under visual guidance. Saline was used as irrigation to maintain clarity during dilation. The dilation technique was implemented to establish percutaneous access tract in six PCNL simulator models made from fresh porcine kidney placed inside an eviscerated chicken carcass and four female swine (eight kidneys) to experimentally evaluate its feasibility and efficacy.

RESULTS

All tracts were successfully established with dilation through the intervening tissue layers, approach into the target calix, as well as access sheath placement being visually monitored through the dilator wall to confirm accuracy. All procedures were free of dilation-related complications such as collecting system perforation, excessive bleeding (in-vivo model), or loss of access. The limited number of animal models and lack of randomized comparative study with other dilator modalities were major drawbacks of the study.

CONCLUSIONS

The study demonstrates feasibility of percutaneous access tract dilation using a Visual dilator system. This technique can provide visual confirmation of accuracy in dilation to improve safety and efficacy of the procedure.

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.

A comparison of metal telescopic dilators and Amplatz dilators for nephrostomy tract dilation in percutaneous nephrolithotomy

BACKGROUND AND PURPOSE

Nephrostomy tract dilation is one of the important steps in percutaneous renal surgery. We present our experiences with using Amplatz and metal telescopic dilators (Alken) to create a percutaneous tract and compare the advantages and risk factors of both procedures.

PATIENTS AND METHODS

We retrospectively reviewed the medical records of 173 patients who had undergone 188 percutaneous nephrolithotomy procedures between April 2007 and December 2010. The nephrostomy tracts had been created by using Amplatz (67 cases) or Alken dilators (121 cases). Total operative time, scope time, tract formation time, decrease in hemoglobin concentrations, blood transfusion rates, tract dilation failures, and the cost of both systems were compared between the groups.

RESULTS

There were no statistically significant differences in total operative time (103.3 ± 46.5 vs 99.1 ± 44.4 min, P=0.583), scope time (5.23 ± 3.06 vs 5.28 ± 2.52 min, P=0.732), decrease in hemoglobin concentration (-1.5 ± 1.2 vs-1.3 ± 1.1 mg/dL, P=0.230), blood transfusion rates (13.4% vs 11.6%, P=0.709), and tract dilation failure rates (6.0% vs 1.7%, P=0.107) for Amplatz and Alken dilation groups, respectively. A shorter tract formation time (6.56 ± 3.04 vs 5.42 ± 3.07 min, P<0.001) was observed in the Alken dilation group. The approximate costs per each case were $220 and $7.25 for Amplatz and Alken dilation groups, respectively.

CONCLUSIONS

The Alken dilation technique produces similar results to the Amplatz dilators in terms of efficiency, safety, and total operative time. Notwithstanding, it is more cost-effective in comparison.

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.

Operating times and bleeding complications in percutaneous nephrolithotomy: a comparison of tract dilation methods in 5,537 patients in the Clinical Research Office of the Endourological Society Percutaneous Nephrolithotomy Global Study

PURPOSE

The study investigated factors that affect operating times and bleeding complications associated with percutaneous nephrolithotomy (PCNL) in the PCNL Global Study.

PATIENTS AND METHODS

All patients who underwent PCNL for primary or secondary treatment of kidney stone indications during the study period (November 2007-December 2009) were eligible for inclusion. PCNL procedures were performed according to local clinical guidelines and practices. Nephrostomy tract dilation was performed using balloon dilation, metal telescopic dilation, or Amplatz serial dilation. Hematologic complications assessed included bleeding rates, transfusion rates, and preoperative and postoperative hematocrit values.

RESULTS

The median operating time with balloon dilation (n=2277) was significantly longer than with telescopic/serial dilation (n=3260) at 94.0 vs 60.0 minutes, respectively (P<0.0001). In the balloon dilation group, there was significantly more bleeding (9.4% vs 6.7%, respectively; P<0.0001) and more transfusions (7.0% vs 4.9%, respectively; P=0.001) compared with the telescopic/serial dilator group. Univariate analysis showed that the probability of bleeding complications was higher with balloon vs telescopic/serial dilation (odds ratio [OR] 1.75; P=0.0001) and larger sheath size (OR 1.42; P=0.0001). By multivariate analysis, sheath size but not dilation method was predictive of bleeding complications. Other significant predictive factors included operating time, stone load, and caseload.

CONCLUSION

This study shows that in PCNL, factors that are associated with bleeding/transfusion include sheath size, operating time, stone load, and caseload.

The modified Clavien classification system: a standardized platform for reporting complications in transurethral resection of the prostate

Purpose

The aim of the study was to evaluate the applicability of the modified Clavien classification system (CCS) in grading perioperative complications of transurethral resection of the prostate (TURP).

Methods

All patients with benign prostatic hyperplasia submitted to monopolar TURP from January 2006 to February 2008 at a non-academic center were evaluated for complications occurring up to the end of the first postoperative month. All complications were classified according to the modified CCS independently by two urologists, and the final decision was based on consensus. If multiple complications per patient occurred, categorization was done in more than one grade. Results were presented as complication rates per grade.

Results

Forty-four complications were recorded in 31 out of 198 patients (overall perioperative morbidity rate: 15.7%), and their grading was generally easy, non-time-consuming and straightforward. Most of them were classified as grade I (59.1%) and II (29.5%). Higher grade complications were scarce (grade III: 2.3% and grade IV: 6.8%, respectively) There was one death (grade V: 2.3%) due to acute myocardial infarction (overall mortality rate: 0.5%). Negative outcomes such as mild dysuria during this early postoperative period or retrograde ejaculation were considered sequelae and were not recorded. Nobody was complicated with severe dysuria. There was one re-operation due to residual adenoma (0.5%).

Conclusions

The modified CCS represents a straightforward and easily applicable tool that may help urologists to classify the complications of TURP in a more objective and detailed way. It may serve as a standardized platform of communication among clinicians allowing for sound comparisons.