The ideal puncture approach for PCNL: Fluoroscopy, ultrasound or endoscopy?

Is percutaneous nephrolithotripsy feasible in ipsilateral lumbar incisional hernia? A report of two patients

Incisional hernia refers to an abdominal wall defect at the site of a previous surgical incision. In this paper, we describe two patients who previously underwent open kidney stone surgery several years ago and had the ipsilateral recurrent stones. They were both managed by a mini percutaneous nephrolithotripsy (PCNL) to treat kidney stones. Case 1 was a 50-year-old female with right recurrent staghorn stones after 5 years of open surgery and required two PCNL procedures to achieve stone-free status. Case 2 was a 74-year-old male with significant comorbidities who had a right 27 mm recurrent kidney stone after 10 years of open nephrolithotomy. Both patients experienced no postoperative complications after PCNL. These cases show that in cases of lumbar incisional scar hernias, mini PCNL with ultrasound guidance and proper patient positioning can be an optimal approach for kidney stone treatment.

Ultrasound-guided renal puncture followed by endoscopically guided tract dilatation vs standard fluoroscopy-guided percutaneous nephrolithotomy for non-opaque renal stones; a randomized clinical trial

This study was designed to evaluate the non-inferiority of ultrasound puncture followed by endoscopically guided tract dilatation compared to the standard fluoroscopy-guided PCNL. Forty patients with non-opaque kidney stones eligible for PCNL were randomly divided into two groups. The standard fluoroscopy-guided PCNL using the Amplatz dilator was performed in the XRAY group. In the SONO group, the Kidney was punctured under an ultrasound guide followed by tract dilatation using a combination of the Amplatz dilator based on the tract length and an endoscopically guided tract dilatation using a bi-prong forceps in cases of short-advancement. The primary outcome was successful access. In 90% of cases in the XRAY and 95% in the SONO group access dilatation process was performed uneventfully at the first attempt (p = 0.5). In 45% of cases in the SONO group, bi-prong forceps were used as salvage for short-advancement. In one case in the X-ray group over-advancement occurred. One month after surgery, the stone-free rate on the CT-scan was 75% for the X-ray group and 85% for the SONO group (p = 0.4). There were no significant differences in operation time, hospitalization duration, transfusion, or complication rates between the two groups. We conclude that ultrasound-guided renal puncture, followed by endoscopically guided tract dilatation can achieve a high success rate similar to X-ray-guided PCNL while avoiding the harmful effects of radiation exposure and the risk of over-advancement.

Reducing hand radiation during renal access for percutaneous nephrolithotomy: a comparison of radiation reduction techniques

Percutaneous nephrolithotomy confers the highest radiation to the urologist's hands compared to other urologic procedures. This study compares radiation exposure to the surgeon's hand and patient's body when utilizing three different techniques for needle insertion during renal access. Simulated percutaneous renal access was performed using a cadaveric patient and separate cadaveric forearm representing the surgeon's hand. Three different needle-holding techniques were compared: conventional glove (control), a radiation-attenuating glove, and a novel needle holder. Five 300-s fluoroscopy trials were performed per treatment arm. The primary outcome was radiation dose (mSv) to the surgeon's hand. The secondary outcome was radiation dose to the patient. One-way ANOVA and Tukey's B post-hoc tests were performed with p < 0.05 considered significant. Compared to the control (3.92 mSv), both the radiation-attenuating glove (2.48 mSv) and the needle holder (1.37 mSv) reduced hand radiation exposure (p < 0.001). The needle holder reduced hand radiation compared to the radiation-attenuating glove (p < 0.001). The radiation-attenuating glove resulted in greater radiation produced by the C-arm compared to the needle holder (83.49 vs 69.22 mGy; p = 0.019). Patient radiation exposure was significantly higher with the radiation-attenuating glove compared to the needle holder (8.43 vs 7.03 mSv; p = 0.027). Though radiation-attenuating gloves decreased hand radiation dose by 37%, this came at the price of a 3% increase in patient exposure. In contrast, the needle holder reduced exposure to both the surgeon's hand by 65% and the patient by 14%. Thus, a well-designed low-density needle holder could optimize radiation safety for both surgeon and patient.

Ultrasound-guided percutaneous nephrolithotomy (PCNL) success rates in patients with elevated body mass index: a comparative study

Percutaneous nephrolithotomy (PCNL) is considered gold standard treatment of renal stones larger than 20 mm. Several studies have shown that ultrasound guidance during this procedure is more effective and safer than fluoroscopy. A higher body mass index (BMI) can make ultrasound-guided renal access more difficult and unsuccessful. We present a prospective analysis and comparison of ultrasound-guided PCNL in patients with normal and increased body mass index. We performed a prospective comparison of patients who underwent ultrasound-guided PCNL to remove renal stones by a single surgeon between 2020 and 2022. Patients with BMIs greater than 30 (mean 33.87-obese) were compared to those with BMIs less than 30 (mean 25.69-non-obese). Demographic, perioperative, and follow-up data were collected, analyzed, and included in this study. Total of 98 consecutive patients, with 49 patients in each group were analyzed. No statistically significant differences were observed in terms of stone volume (P = 0.085), stone density (P = 0.5590), location of renal access (P = 0.108), surgery duration (P = 0.38), blood loss (P = 0.54), or laboratory changes after surgery (P = 0.60). 87.76% of obese patients were stone free per CT scan at follow-up, compared to 73.47% of normal-weight patients (P = 0.1238). According to Clavien-Dindo classification, six patients in the non-obese group experienced grade II (10%) and grade III (2%) complications, as opposed to six patients in the obese group with grade I (2%), grade II (6%), and grade III (2%) complications. There was no significant correlation between body mass index and the success or safety of ultrasound-guided PCNL. Although more challenging, a higher BMI should not be an impediment to performing this approach. This method is safe, with no increased incidence of postoperative complications or compromise in stone-free status postoperatively and can diminish or avoid both patient's and medical team's exposure to ionizing radiation.

Needle Aligned Ultrasound Image-Guided Access Through Dual-Segment Array

Ultrasound (US) guided access for percutaneous nephrolithotomy (PCNL) is gaining popularity in the urology community as it reduces radiation risk. The most popular technique involves manual image-needle alignment. A misaligned needle however needs to be retracted and reinserted, resulting in a lengthened operation time and complications such as bleeding. These limitations can be mitigated through the co-registration between the US array and needle. The through-hole array concept provides the primary solution, including a hole at the center of the array. Because of the central opening, the image-needle alignment is achieved inherently. Previous literature has described applications that are limited to superficial and intravascular procedures, suggesting that developing a through-hole array for deeper target applications would be a new breakthrough.

OBJECTIVE

Here, we present a dual-segment array with a central opening. As the prototype development, two segments of 32-element arrays are combined with an open space of 10 mm in length in between them.

METHOD

We conducted phantom and ex-vivo studies considering the target depth of the 80-100 mm range. The image quality and needle visibility are evaluated by comparing the signal-to-noise ratio (SNR), full width at half maximum (FWHM), and contrast-to-noise ratio (CNR) results measured with a no-hole linear array under equivalent conditions. An ex-vivo study is performed using porcine kidneys with ceramic balls embedded to evaluate the needle access accuracy.

RESULTS AND CONCLUSION

The mean needle access error of 20 trials is found to be 2.94 ±1.09 mm, suggesting its potential impact on realizing a simple and intuitive deep US image-guided access.

Ultrasound versus fluoroscopy as imaging guidance for percutaneous nephrolithotomy: A systematic review and meta-analysis

OBJECTIVES

To determine whether the outcomes of ultrasound-guided percutaneous nephrolithotomy (UG-PCNL), an alternative to traditional fluoroscopy-guided percutaneous nephrolithotomy (FG-PCNL), are comparable.

METHODS

A systematic search of PubMed, Embase, and the Cochrane Library was carried out to discover investigations comparing UG-PCNL to FG-PCNL, and accordingly, a meta-analysis of those studies was performed. The primary outcomes included the stone-free rate (SFR), overall complications based on Clavien-Dindo classification, duration of surgery, duration of patients' hospitalization, and hemoglobin (Hb) drop during the surgery. All statistical analyses and visualizations were implemented utilizing R software.

RESULTS

Nineteen studies, including eight randomized clinical trials (RCTs) and eleven observational cohorts, comprising 3016 patients (1521 UG-PCNL patients) and comparing UG-PCNL with FG-PCNL met the inclusion criteria of the current study. Considering SFR, overall complications, duration of surgery, duration of hospitalization, and Hb drop, our meta-analysis revealed no statistically significant difference between UG-PCNL and FG-PCNL patients, with p-values of 0.29, 0.47, 0.98, 0.28, and 0.42, respectively. Significant differences were discovered between UG-PCNL and FG-PCNL patients in terms of the length of time they were exposed to radiation (p-value< 0.0001). Moreover, FG-PCNL had shorter access time than UG-PCNL (p-value = 0.04).

CONCLUSION

UG-PCNL provides the advantage of requiring less radiation exposure while being just as efficient as FG-PCNL; thus, this study suggests prioritizing the use of UG-PCNL.

A comparative study of air pyelogram and contrast pyelogram for initial puncture access and to see its efficacy during percutaneous nephrolithotomy

Objective

The current investigation was aimed to compare the safety, efficacy, adverse effects, and outcome of air pyelogram versus contrast pyelogram for percutaneous nephrolithotomy.

Materials and Methods

This was a cross-sectional study conducted from August 2018 to November 2020, which included 400 patients with a clinical diagnosis of renal calculus and randomly (1:1) assigned into Group I (air pyelogram) and Group II (contrast pyelogram). Air was injected in Group I and diatrizoate meglumine 76% was used in Group II for PCS identification. In the case of difficulty in visualization in either group, a mixture of contrast and air was used. The following parameters were assessed: duration of access, total duration of radiation exposure during access, total attempts needed to puncture the desired calyx, failure rate, complications, and outcomes.

Results

Both the groups were comparable including renal calculus characteristics. The mean (standard deviation) duration of access was 3.08 (1.21) and 5.23 (1.02) min (P < 0.0001) in Groups I and II, respectively; in 85% and 57.5% of patients (P < 0.0001), respectively, the caliceal puncture was done in a single attempt. The duration of radiation exposure was more in Group II (P < 0.0001). The failure rate (22%) was higher and statistically significant in Group II. The stone clearance rate was not statistically significant between the groups (P = 0.380). No patient had hypoxia, cardiopulmonary complications, and air embolism in perioperative period.

Conclusion

Air contrast is effective and safe, and it reduces the duration of caliceal puncture and radiation exposure with lower failure rate. If both air and contrast fail, a combination of both may be effective.

A 3D printing personalized percutaneous puncture guide access plate for percutaneous nephrolithotomy: a pilot study

OBJECTIVE

CT-Urography combined with 3D printing technology, digital design, construction of individualized PCNL puncture guides, and preliminary analyze their efficacy, safety puncture positioning for PCNL.

METHODS

Twenty-two patients with renal calculi were randomly selected at the affiliated Hospital of Xuzhou Medical University during 2017-2018. We randomly divided the patients into two groups: in 10 experimental groups, we used our 3D printing personalized percutaneous puncture guide access plate for PCNL, and in the control group, 12 patients with standard USG guide PCNL. The accuracy of puncture position, puncture time, and intraoperative blood loss was compared.

RESULTS

In the experimental group, 10 patients with 3D printing personalized percutaneous puncture guide access plate. The puncture needle was accessed through the guide plate and verified by the color Doppler. The single puncture, needle position, and depth success rate were 100.00% (10/10). The angles were consistent with the preoperative design. In the control group, 12 patients via USG guided PCNL success rate was 75.00% (9/12). The puncture time and amount of hemorrhage was (7.78 ± 0.94) min and (49.31 ± 6.43) mL, and (9.04 ± 1.09) min and (60.08 ± 12.18) mL, respectively. The above data of the two groups were statistically significant (P < 0.05).

CONCLUSION

3D printing personalized percutaneous nephrolithotomy guide plate for PCNL can improve PCNL renal puncture channel positioning accuracy, shorten puncture time, reduce intraoperative blood loss, bleeding-related complications and provide a new method for PCNL renal puncture positioning, which is worthy of further clinical exploration.

Can Color Doppler Ultrasound Challenge the Paradigm in Percutaneous Nephrolithotomy?

OBJECTIVES

Compare color Doppler (Color) ultrasound-guided puncture to common type-B (Type-B) ultrasound-guided puncture in reducing the incidence of hemorrhagic complications of percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

A total of 348 patients who received PCNL from September 2017 to December 2018 were divided into Color (231 cases) and Type-B groups (117 cases). The avascular area of the target fornix was pinpointed in the Color group while the middle of the target fornix was the default puncture point in the Type-B group. Tract bleeding, nephrostomy tract creation time, operation time, postoperative hemoglobin (Hb) values and serum creatinine (Scr) concentrations, and stone-free rates were analyzed.

RESULTS

Color Doppler imaging revealed that 35.1% of the cases in the Color group (81/231) had variable artery positioning in the target fornix. Tract bleeding and postoperative Hb reduction in the Color group were significantly lower than the Type-B group (10.8% vs 24.8%, P=0.0007, and 4.87±8.58 vs 7.70±8.90 g/L, P=0.0044, respectively). The postoperative hospitalization of the Color group was also shortened (8.3±5.9 vs 9.7±3.0 d, P<0.0001). Although working channel creation took longer in this group (4.2±0.3 vs 3.6±0.2 min, P<0.0001), there were no significant differences in the total operation time between the two groups (39.2±15.2 vs 36.4±16.5 min, P=0.1097) or postoperative Scr and stone-free rates.

CONCLUSION

Vascular variation of the fornix is very common. Consistent puncture of the avascular area of the target fornix significantly lowered tract bleeding and postoperative Hb decrease compared to traditional procedures. Color Doppler ultrasound-guided puncture is thus useful to reduce the incidence of severe hemorrhagic complications of PCNL.

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.

How does puncture modality affect the risk of intraoperative bleeding during percutaneous nephrolithotomy? A prospective randomized trial

INTRODUCTION AND OBJECTIVES

To evaluate the possible effects of two different renal puncture techniques (ultrasound-assisted [US-assisted], fluoroscopic-guided [FG]) on the intraoperative hemorrhage risk during percutaneous nephrolithotomy (PCNL).

MATERIAL AND METHODS

A total of 130 patients with Guy stone scores of 1-2 were prospectively allocated to US-assisted and FG puncture groups by simple randomization. Patients with intraoperative pelvicalyceal rupture and the ones requiring multiple accesses were excluded from the study. Apart from the puncture steps, all other steps of the PCNL procedure were performed with similar techniques by a single surgeon. Patient characteristics, operative data, and postoperative outcomes were compared.

RESULTS

A total of 10 patients were excluded from the study due to intraoperative complications after puncture. Patient demographics and stone characteristics were similar between the two groups (p > 0.05). Mean hemoglobin drop was meaningfully greater in the FG group (1.7 g/dL) when compared with US-assisted group (1.3 g/dL) (p < 0.01). The mean duration of radiation exposure was significantly higher for the FG (p < 0.001). Total operative time, number of attempts for a successful puncture, length of hospital stay, and stone free rates were similar between the groups (p > 0.05). In addition, the remaining complications classified according to the modified Clavien-Dindo grading system were similar between groups (p > 0.05).

CONCLUSION

US-assisted puncture provides significantly decreased level of hemoglobin drop and radiation exposure time when compared with FG.

Minimal invasive percutaneous nephrolithotomy (Mini-PCNL) in children: Ultrasound versus fluoroscopic guidance

BACKGROUND

Miniaturization of endoscopic instruments in percutaneous nephrolithotomy (PCNL) allowed less invasive procedures with low complication rates, especially in children. This study was conducted to evaluate the safety and efficacy of ultrasonography-guided (USG) versus fluoroscopy-guided (FG) mini-PCNL in children.

MATERIALS AND METHODS

This is a retrospective comparative study conducted from June 2015 to June 2020. The sample included 70 children (35 pateints underwent USG mini-PCNL and 35 pateints underwent FG mini-PCNL). They were compared mainly by the patients' demographic characteristics, procedural information, and post-treatment outcomes. In the USG mini-PCNL group, puncturing was performed using a 3.5 MHz US probe, whereas fluoroscopy was utilized in the FG mini- PCNL group.

RESULTS

Both groups were comparable in terms of gender, previous history of failed ESWL, and hydronephrosis grade. The mean stone burden was 15.94 ± 3.69 mm and 19.20 ± 7.41 mm in USG and FG groups, respectively (p = 0.024). The stonefree rate (SFR) was 97.1% in the USG group and 94.3% in the FG group, which was not statistically significant (p = 0.16). Mean operative time in the USG group and FG group was 69.00 ± 13.33 minutes and 63.48 ± 16.90 minutes, respectively. Four (11.4%) patients in the FG group required blood transfusions to restore the hemodynamic state (p = 0.039). Fever was detected in 4 (11.4%) patients in the USG group and 15 (31.4%) patients in the FG group (p = 0.041).

CONCLUSIONS

In children, mini PCNL under USG is safe and as effective as fluoroscopy.

Costovertebral angle as a novel tool for predicting the thoracic complication risk following percutaneous nephrolithotomy requiring supracostal access

INTRODUCTION

The objective of this study was to determine whether the costovertebral angle (CVA) and other factors can predict the risk of thoracic complications following percutaneous nephrolithotomy (PCNL).

METHODS

The data of patients who underwent prone PCNL with supracostal access at Suleyman Demirel University Hospital between January 2015 and December 2019 were retrospectively reviewed. Patients' demographics information (age, sex, body mass index [BMI], stone size, and stone location), operative data (supracostal access site, renal puncture site, and laterality), and postoperative thoracic complications (pleural injury) were evaluated. The CVA was measured on preoperative posteroanterior chest X-ray images. The mean CVA of patients with and without thoracic complications was evaluated.

RESULTS

A total of 89 patients (mean age 46.12±15.66 years; 59 men and 30 women) with supracostal access were included in the study. Thoracic complications occurred in 17 (19.1%) patients. Nine (52.9%) hemothorax cases, five (29.4%) pneumothorax cases, and three (17.7%) urinothorax cases were detected. There was a statistically significant difference in the complication rate compared to the percutaneous access site (10^th-11^th supracostal vs. 11^th-12^th supracostal, p=0.004). The mean CVA was significantly lower in patients with complications (45.47±3.59) than in those without complications (53.26±5.98) (p=0.000). No association was found (p>0.05) with age, sex, BMI, laterality, stone surface area, and access site among patients with and without thoracic complications.

CONCLUSIONS

Preoperative CVA can be an effective tool in predicting the risk of postoperative thoracic complications.

How does puncture modality affect the risk of intraoperative bleeding during percutaneous nephrolithotomy? A prospective randomized trial

INTRODUCTION AND OBJECTIVES

To evaluate the possible effects of two different renal puncture techniques (ultrasound-assisted [US-assisted], fluoroscopic-guided [FG]) on the intraoperative hemorrhage risk during percutaneous nephrolithotomy (PCNL).

MATERIAL AND METHODS

A total of 130 patients with Guy stone scores of 1-2 were prospectively allocated to US-assisted and FG puncture groups by simple randomization. Patients with intraoperative pelvicalyceal rupture and the ones requiring multiple accesses were excluded from the study. Apart from the puncture steps, all other steps of the PCNL procedure were performed with similar techniques by a single surgeon. Patient characteristics, operative data, and postoperative outcomes were compared.

RESULTS

A total of 10 patients were excluded from the study due to intraoperative complications after puncture. Patient demographics and stone characteristics were similar between the two groups (P>.05). Mean hemoglobin drop was meaningfully greater in the FG group (1.7g/dL) when compared with US-assisted group (1.3g/dL) (P<.01). The mean duration of radiation exposure was significantly higher for the FG (P<.001). Total operative time, number of attempts for a successful puncture, length of hospital stay, and stone free rates were similar between the groups (P>.05). In addition, the remaining complications classified according to the modified Clavien-Dindo grading system were similar between groups (P>.05).

CONCLUSION

US-assisted puncture provides significantly decreased level of hemoglobin drop and radiation exposure time when compared with FG.

Air vs contrast pyelogram for initial puncture access in percutaneous nephrolithotomy: a randomized controlled trial

Percutaneous nephrolithotomy (PCNL) is a standard procedure for large renal stones. Contrast (traditionally) as well as air is being used to delineate pelvi-calyceal system (PCS) to perform initial puncture. Contrast, when used has certain disadvantages including poor differentiation of anterior and posterior calyces. In this interim analysis of 122 patients of a prospective study subjects were stratified in two groups: in group 1, contrast was used while in group 2, air was used to delineate PCS. Out of 122,103 patients underwent puncture by contrast or air exclusively while 19 patients required mix of contrast and air (14 patients failed puncture using contrast while 5 using air). Mean dosage of radiation exposure (8.43 vs. 14.26 mGy), duration of radiation exposure (0.66 vs. 1.02 min), access time (3.72 vs. 5.84 min), were less in group 2 as compared to group 1. 84.5% of patients underwent puncture in single attempt in group 2 as compared to 56.25% in group 1. Five patients had post-operative fever and one had trans-pleural tract dilation. Complete stone clearance was seen in 94.8% of patients using air to only 75% of patients using contrast. Conclusion: Air pyelogram is a feasible, safe, cost effective and efficient access alternative to contrast pyelogram and in difficult situation a mixture of both is better than using one.

Complete Ultrasound-guided Percutaneous Nephrolithotomy in Prone and Supine Positions: A Randomized Controlled Study

OBJECTIVES

To evaluate the safety, efficacy, adverse events, and feasibility of ultrasound guided percutaneous nephrolithotomy (US-PCNL) in the management of large renal stones in supine and prone positions and to point out the practical considerations related to these techniques in comparison with standard PCNL.

PATIENTS AND METHODS

This study was conducted between August 2013 to September 2018 as a prospective randomized and controlled study. A total of 392 consecutive patients with nephrolithiasis >2 cm were randomly assigned to undergo ultrasound PCNL in prone (P-US-PCNL) (132 patients); supine position (S-US-PCNL) (129 patients) or conventional PCNL (C-PCNL) (131 patients). The preoperative parameters, the intraoperative findings, operative time, hospital stay, perioperative morbidities, stone free rate, and related data were recorded.

RESULTS

The demographic and the baseline characteristics were comparable in all study groups. The mean number of trails and time for successful puncture in P-US-PCNL, S-US-PCNL, and C-PCNL were 1.9 ± 1, 2.3 ± 1.2, and 1.7±1, respectively (P < .001), and 15.8 ± 5.8, 19.3 ± 9.4, and 16.5 ± 8.1 seconds, respectively (P < .001). The operation time was 69 ± 22, 75 ± 23, and 72 ± 27 minutes, respectively, (P > .05). The mean nephrostomy time and length of hospital stay were 3 ± 1.3, 3.4 ± 1.5, 3.2 ± 1.2 hours, respectively, and 3.8 ± 1.5, 4.1 ± 1.5, 3.9 ± 1.3 days, respectively (P > .05). The mean percentage decrease in hemoglobin concentration was 1.65 ± 0.66, 1.77 ± 0.78, and 2.1 ± 0.9, respectively (P < .001), overall stone clearance was 88%, 79%, and 85%, respectively (P > .05). Complications were acceptable and similar between groups.

CONCLUSION

US-PCNL either in prone or supine position is as effective, feasible, and safe as C-PCNL with zero radiation exposure.

Ultrasound-guided versus fluoroscopy-guided percutaneous nephrolithotomy: a systematic review and meta-analysis

PURPOSE

To evaluate the efficacy and safety of ultrasound-guided (UG) versus fluoroscopy-guided (FG) percutaneous nephrolithotomy (PCNL).

METHODS

A systematic search of PubMed (MEDLINE), Embase, and the Cochrane Library was conducted to identify randomized controlled trials that compared UG-PCNL with FG-PCNL, and a meta-analysis of those studies was completed. The primary outcomes assessed were stone-free rate (SFR) and complication rate. Secondary outcomes assessed were the successful access-creation rate, time necessary for entrance into the target calyx, auxiliary procedure rate, transfusion rate, hemoglobin decrease after surgery, surgery duration, and hospital stay.

RESULTS

Eight studies comprising 966 patients were included in the meta-analysis. Compared with FG-PCNL, UG-PCNL had comparable stone-free rates [odds ratio (OR) 0.95; 95% confidence interval (CI) 0.67-1.35; p = 0.79] irrespective of the patient's position, and a favorable safety profile resulting in a lower complication rate (OR 0.56; 95% CI 0.36-0.86; p = 0.009). No statistical difference was found between UG and FG groups in secondary outcomes.

CONCLUSIONS

UG-PCNL is as effective as FG-PCNL and has the advantage of lower complication rates. In addition, UG-PCNL could be performed with patients in the supine position without compromising its efficacy.

Real-Time Ultrasound-Guided Percutaneous Nephrolithotomy Using Newly Developed Wireless Portable Ultrasound: A Single-Center Experience

OBJECTIVES

To assess the feasibility and utility of a newly developed wireless portable ultrasound "UProbe- 2" for puncture guidance in percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

The UProbe-2 consists of a probe with integrated ultrasound circuit boards inside, an intelligent terminal that installed specific ultrasound software, and a puncture trestle. The probe can connect to an intelligent terminal via WI-FI. It was used to guide puncture in PCNL in 31 patients who suffered kidney stones or large impacted proximal upper ureteral stones with hydronephrosis from June 2016 to July 2017. Patients' characteristics as well as parameters during operation were collected.

RESULTS

PCNL was successfully performed in all patients with the guidance of the UProbe-2. The mean (standard deviation) puncture time was 3.6 (0.9) minutes, and the median operative duration was 50 (35-80) minutes. The primary stone clearance rate was 87% (27/31). No major intraoperative or postoperative complications occurred.

CONCLUSION

The UProbe-2 ultrasound is safe and effective for puncture guidance during PCNL according to this initial study. It could provide a new and alternative choice for guidance of PCNL. However, more clinical trials especially randomized controlled trials should be performed.

Invited review: the tale of ECIRS (Endoscopic Combined IntraRenal Surgery) in the Galdakao-modified supine Valdivia position

Modern-day percutaneous nephrolithotomy (PNL) has undergone considerable evolution, mainly driven by the improvement in access techniques, endoscopic instrumentation technology, lithotripsy devices and drainage management. The introduction of the supine and supine-modified positions is also part of this evolution, enabling comfortable and safe procedures from an anaesthesiological point of view, and an easy combined retrograde surgery [Endoscopic Combined IntraRenal Surgery (ECIRS)], allowing tailoring of the procedure on the patient, the dynamic anatomy of the collecting system and the urolithiasis. The conceptual value of ECIRS extends beyond the single diagnostic and active advantages due to the simultaneous contribution of the flexible retrograde ureteroscopy: the merit consists in the promotion of the versatile attitude of the urologist, and in the fulfillment of a personalized stone management. ECIRS has no pretensions of superiority, but for sure is a new safe and effective way of interpreting PNL, in the hands of an experienced surgical team.

Ultrasound - guided access during percutaneous nephrolithotomy: entering desired calyx with appropriate entry site and angle

Objectives:

To evaluate the success of ultrasonography directed renal access in entering the target calyx from proper entry site and in the direction of renal pelvis during percutaneous nephrolithotomy (PCNL).

Materials and Methods:

PCNL cases who were operated on by one fellow from May-June 2014 were included in this study. A vertically placed ultrasound probe on the patient flank in prone position was used to identify the preselected target calyx. Needle was advanced through needle holder and fluoroscopy was used to document the entered calyx, site and angle of entry.

Results:

Successful entering to the target calyx was achieved in 43 cases (91%). Successful entry with appropriate entry site and angle was observed in 34 cases (72%). Reasons for failure were minimal hydronephrosis, upper pole access and high lying kidneys.

Conclusions:

Although it is feasible to access a preselected calyx by ultrasonography guidance during PCNL, but entry to the calyx from the appropriate site and direction is another problem and needs more experience. In cases of minimal hydronephrosis, superior pole access or high lying kidneys, ultrasonography is less successful and should be used with care.

Comparison of Two Treatment Methods "One Shot" and "Sequential" on Reduction the Level of Hemoglobin in Patients with Percutaneous Nephrolithotripsy in Al Zahra Hospital in 2012-2013

BACKGROUND

Access dilation is the most important part of percutaneous nephrolithotripsy (PCNL) that is done by different methods, especially metal telescoping and one shot. In this study, two different methods of access dilation one shot and telescoping were compared.

MATERIALS AND METHODS

In observational cross-sectional study, 240 patients who were a candidate for PCNL were selected and randomly divided into two groups. The first group was undergone one-shot method and the second group was undergone telescoping method. The decrease in hemoglobin (Hb), duration of hospitalization and the time of radiation exposure during access dilation was compared in two groups by SPSS software version 21, (SPSS Inc., Chicago, IL, USA).

RESULTS

The decrease of Hb level after intervention in one-shot group was 1.08 ± 1.23 g/dl and in telescoping, group was 1.51 ± 1.08 g/dl with no difference statistically (P = 0.37). The mean duration of hospitalization in one shot and telescoping group were 2.36 ± 0.67 and 2.28 ± 0.61 days, respectively. According to t-test, there was no significant difference between the two groups (P = 0.37). Average radiation exposure in one shot group was 7.13 s and in telescoping, group was 35.75 s, and there was a significant difference between the two groups (P < 0.001).

CONCLUSION

One-shot method is superior to telescoping method due to less time for radiation exposure and no more blood loss and other complications during PCNL.

Using an abdominal phantom to teach urology residentes ultrasound-guided percutaneous needle placement

INTRODUCTION

To assess the effect of a hands-on ultrasound training session to teach urologic trainees ultrasound-guided percutaneous needle placement.

MATERIALS AND METHODS

University of California, San Francisco (UCSF) urology residentes completed a time trial, placing a needle into a phantom model target under ultrasound guidance. Participants were randomized into three educational exposure groups: Group 1's time trial occurred prior to any teaching intervention, group 2's after experiencing a hands-on training module, and group 3's after exposure to both the training module and one-on-one attending feedback. Needle placement speed and accuracy as well as trainees' perceived confidence in utilizing ultrasound were measured.

RESULTS

The study cohort consisted of 15 resident trainees. Seven were randomized to group 1, three to group 2, and five to group 3. All residents reported minimal prior ultrasound experience. Their confidence in using ultrasound improved significantly after completing the training module with the most significant improvement seen among junior residents. Time to needle placement was fastest after receiving attending feedback (46.6sec in group 3 vs. 82.7sec in groups 1 and 2, p<0.01). Accuracy also improved with attending feedback, though the number of repositioning attempts did not differ significantly between groups.

CONCLUSIONS

A hands-on training module and use of an abdominal phantom trainer increased resident confidence and skill in their use of ultrasound to guide percutaneous needle positioning. Attending feedback is critical for improving accuracy in needle guidance toward a target. Ultrasound-guided needle positioning is a teachable skill and can be applicable to multiple urologic procedures.

A Comparative Study of Antegrade Air Pyelogram and Retrograde Air Pyelogram for Initial Puncture Access during Percutaneous Nephrolithotomy

INTRODUCTION

Access into the collecting system is considered to be the most critical step for Percutaneous Nephrolithotomy (PCNL).

AIM

The present study provides a comparative view into antegrade air pyelography and retrograde air pyelography procedures for percutaneous renal access.

MATERIALS AND METHODS

A cross-sectional study was conducted on 100 patients with radiopaque renal calculi indicated for PCNL procedure. These patients were randomly assigned to two groups namely antegrade air pyelogram group (Group I) and retrograde air pyelogram group (Group II). In antegrade air pyelogram group, the collecting system was delineated by targeting the renal stone using a 22 gauge spinal needle where the patients were in the prone position. In another group, the collecting system was delineated by retrograde air pyelogram under fluoroscopy guidance. The method of tract dilatation and stone extraction were the same in both groups for comparison of outcome and complication.

RESULTS

The mean age of patients was 41.7±13 and 41.4±13.6 years in Group-I and Group-II respectively. The male to female ratio in Groups I and II was 35/15 (70.00%) and 38/12 (76.00%) respectively. In Group-I the average duration of access was 2.66±1.0 minutes after prone positioning whereas it was recorded to be 19.48±5.0 minutes in Group-II, after lithotomy followed by prone positioning of the patient. Duration of radiation exposure was almost similar in both groups. Additional procedural cost was significantly higher in Group II.

CONCLUSION

Our study indicated that access for PCNL using antegrade air pyelogram can be a cost-effective and acceptable alternative to retrograde air pyelogram with decreased access time.

X-ray-free Ultrasound-guided Percutaneous Nephrolithotomy: How to Select the Right Patient?

OBJECTIVE

To identify factors associated with successful ultrasound guidance for each surgical step of ultrasound-guided percutaneous nephrolithotomy (PCNL).

PATIENTS AND METHODS

Consecutive patients undergoing PCNL between March 2015 and June 2016 were prospectively enrolled. An attempt was made to use ultrasound guidance in renal access, tract dilation, and nephrostomy tube placement for each patient. For steps during which ultrasound guidance was unsuccessful, fluoroscopic screening was applied. Regression analysis identified patient characteristics associated with successful use of ultrasound guidance.

RESULTS

A total of 96 patients composed this cohort, with a mean body mass index of 28.7 kg/m2. Mean stone size was 33.1 ± 18.9 mm, and no hydronephrosis was found in 63.5% of cases. Fluoroscopic screening was required for renal access in 27 cases (28.1%), tract dilation in 38 (39.6%), and nephrostomy tube placement in 80 (83.3%). Multivariate analysis demonstrated that successful ultrasound guidance was significantly associated with the presence of hydronephrosis for renal access and the absence of staghorn calculi for tract dilation. Ultrasound-guided nephrostomy tube placement appeared linked to surgeon experience.

CONCLUSION

To achieve completely x-ray-free ultrasound-guided PCNL, the ideal patient should have a hydronephrotic collecting system with no staghorn stone present. For practitioners looking to adopt ultrasound guidance into their PCNL practice, these represent the most appropriate patients to safely initiate a surgical experience.

Mini access guide to simplify calyceal access during percutaneous nephrolithotomy: A novel device

Introduction:

A precise puncture of the renal collecting system is the most essential step for percutaneous nephrolithotomy (PCNL). There are many techniques describing this crucial first step in PCNL including the bull's eye technique, triangulation technique, free-hand technique, and gradual descensus technique. We describe a novel puncture guide to assist accurate percutaneous needle placement during bull's eye technique.

Methods:

The mini access guide (MAG) stabilizes the initial puncture needle by mounting it on an adjustable multidirectional carrier fixed to the patient's skin, which aids in achieving the “bull's eye” puncture. It also avoids a direct fluoroscopic exposure of the urologist's hand during the puncture. Sixty consecutive patients with solitary renal calculus were randomized to traditional hand versus MAG puncture during bull's eye technique of puncture and the fluoroscopy time was assessed.

Results:

The median fluoroscopy screening time for traditional free-hand bull's eye and MAG-guided bull's eye puncture (fluoroscopic screening time for puncture) was 55 versus 21 s (P = 0.001) and the median time to puncture was 80 versus 55 s (P = 0.052), respectively. Novice residents also learned puncture technique faster with MAG on simulator.

Conclusion:

The MAG is a simple, portable, cheap, and novel assistant to achieve successful PCNL puncture. It would be of great help for novices to establish access during their learning phase of PCNL. It would also be an asset toward significantly decreasing the radiation dose during PCNL access.

The learning curve for access creation in solo ultrasonography-guided percutaneous nephrolithotomy and the associated skills

AIM

The aim of the current trial was to evaluate the learning curve of access creation through solo ultrasonography (US)-guided percutaneous nephrolithotomy (PCNL), and clarify the technical details of the procedure.

MATERIALS AND METHODS

We evaluated the first 240 solo US-guided PCNLs performed by one surgeon at our institution. The data including the puncture procedure, access characteristics, access-related complications and stone-free rates were assessed in four sequential groups.

RESULTS

The puncture duration and number of times decreased from a mean of 4.4 min and 2.1 times for the first 60 patients to 1.3 min and 1.2 times for the last 60 patients. There was a significant decrease from 3.7 min and 1.8 times for the 61th-120th patients to 1.5 min and 1.3 times for the 121th-180th patients. All of the access-related severe bleeding appeared in the first 120 patients, while perforations only occurred in the first 60 patients. The stone-free rates were 68.3, 83.3, 90.0, and 93.3% for the four sequential groups.

CONCLUSION

The increase in experience lead to an improvement in the puncture duration and times, which accompany with better stone-free rates and lower complications. We propose that 60 operations are sufficient to gain competency, and a cutoff point of 120 operations will allow the surgeon to achieve excellence in the solo US-guided PCNL.

Ultrasound Guidance Reduces Percutaneous Nephrolithotomy Cost Compared to Fluoroscopy

OBJECTIVE

To examine the cost factors associated with ultrasound and fluoroscopic guidance for percutaneous nephrolithotomy (PCNL) and to determine which method can be performed at a lower cost per case.

METHODS

A cost comparison study was performed utilizing clinical data from a prospectively maintained research database. We included the most recent 33 consecutive ultrasound-guided PCNL cases in 2016 and the most recent 40 consecutive fluoroscopy-guided PCNL cases before the operative surgeon transitioned to ultrasound guidance in May 2014. The total operative time and clinical outcomes were examined. Costs were extracted from the institution accounting systems and given a uniform multiplier to protect institutional financial reporting confidentiality. Comparisons were made using the Student t test and the chi-squared test.

RESULTS

After excluding outliers, 71 PCNL procedures were included in the analysis. Demographic data and stone characteristics were not different between ultrasound-guided and fluoroscopy-guided groups. However, the mean operative time for ultrasound-guided PCNL was significantly shorter (99.8 ± 27.0 vs 144.9 ± 55.1 minutes, P < .05). When capital equipment costs were included, the mean total cost per case of ultrasound-guided PCNL was approximately 30% less than fluoroscopy-guided PCNL (simulated costs with a uniform multiplier; $5258.90 ± 957.12 vs $7508.60 ± 1163.83, P < .05). Postoperative clinical outcomes were comparable between the 2 groups.

CONCLUSION

When capital costs are included, ultrasound-guided PCNL can produce comparable clinical outcomes to fluoroscopy-guided procedures at a lower cost to the institution. Shorter operative time drives significant savings with the adoption of ultrasound guidance, which may be magnified with increasing case volume. Using ultrasound imaging during PCNL may be more cost-effective compared to fluoroscopy and warrants further study.

Feasibility of Retrograde Ureteral Contrast Injection to Guide Ultrasonographic Percutaneous Renal Access in the Nondilated Collecting System

OBJECTIVES

Ultrasound-guided percutaneous nephrolithotomy (PCNL) has become increasingly utilized. Patients with nondilated collecting systems represent a challenge: the target calix is often difficult to visualize. Here we report pilot study results for retrograde ultrasound contrast injection to aid in percutaneous renal access during ultrasound-guided PCNL.

PATIENTS AND METHODS

From April to July 2016, consecutive patients over the age of 18 years with nondilated collecting systems on preoperative imaging who presented for PCNL were enrolled. B-mode ultrasound imaging was compared with contrast-enhanced mode with simultaneous retrograde injection of Optison™ via an ipsilateral ureteral catheter.

RESULTS

Five patients (four males and one female) with renal stones underwent PCNL with retrograde ultrasound contrast injection during the study period. Mean body mass index was 28.3 ± 5.6 kg/m² and mean stone size was 24.5 ± 12.0 mm. Under B-mode ultrasound, all patients demonstrated nondilated renal collecting systems that appeared as hyperechoic areas, where it was difficult to identify a target calix for puncture. Retrograde contrast injection facilitated delineation of all renal calices initially difficult to visualize under B-mode ultrasound. Renal puncture was then performed effectively in all cases with a mean puncture time of 55.4 ± 44.8 seconds. All PCNL procedures were completed without intraoperative complications and no adverse events related to ultrasound contrast injection occurred.

CONCLUSION

Retrograde ultrasound contrast injection as an aide for renal puncture during PCNL is a feasible technique. By improving visualization of the collecting system, it facilitates needle placement in challenging patients without hydronephrosis. Future larger scale studies comparing its use to standard ultrasound-guided technique will be required to validate this concept.

A prospective and randomised trial comparing fluoroscopic, total ultrasonographic, and combined guidance for renal access in mini-percutaneous nephrolithotomy

OBJECTIVE

To compare the safety and efficacy of fluoroscopic guidance (FG), total ultrasonographic guidance (USG), and combined ultrasonographic and fluoroscopic guidance (CG) for percutaneous renal access in mini-percutaneous nephrolithotomy (mini-PCNL).

PATIENTS AND METHODS

The present study was conducted between July 2014 and May 2015 as a prospective randomised trial at the First Affiliated Hospital of Guangzhou Medical University. In all, 450 consecutive patients with renal stones of >2 cm were randomised to undergo FG, USG, or CG mini-PCNL (150 patients for each group). The primary endpoints were the stone-free rate (SFR) and blood loss (haemoglobin decrease during the operation and transfusion rate). Secondary endpoints included access failure rate, operating time, and complications. S.T.O.N.E. score was used to document the complexity of the renal stones. The study was registered at http://clinicaltrials.gov/ (NCT02266381).

RESULTS

The three groups had similar baseline characteristics. With S.T.O.N.E. scores of 5-6 or 9-13, the SFRs were comparable between the three groups. For S.T.O.N.E. scores of 7-8, FG and CG achieved significantly better SFRs than USG (one-session SFR 85.1% vs 88.5% vs 66.7%, P = 0.006; overall SFR at 3 months postoperatively 89.4% vs 90.2% vs 69.8%, P = 0.002). Multiple-tracts mini-PCNL was used more frequently in the FG and CG groups than in the USG group (20.7% vs 17.1% vs 9.5%, P = 0.028). The mean total radiation exposure time was significantly greater for FG than for CG (47.5 vs 17.9 s, P < 0.001). The USG had zero radiation exposure. There was no significant difference in the haemoglobin decrease, transfusion rate, access failure rate, operating time, nephrostomy drainage time, and hospital stay among the groups. The overall operative complication rates using the Clavien-Dindo grading system were similar between the groups.

CONCLUSIONS

Mini-PCNL under USG is as safe and effective as FG or CG in the treatment of simple kidney stones (S.T.O.N.E. scores 5-6) but with no radiation exposure. FG or CG is more effective for patients with S.T.O.N.E. scores of 7-8, where multiple percutaneous tracts may be necessary.

Ultrasound-Guided Renal Access for Percutaneous Nephrolithotomy: A Description of Three Novel Ultrasound-Guided Needle Techniques

Ultrasound-guided renal access for percutaneous nephrolithotomy (PCNL) is a safe, effective, and low-cost procedure commonly performed worldwide, but a technique underutilized by urologists in the United States. The purpose of this article is to familiarize the practicing urologist with methods for ultrasound guidance for percutaneous renal access. We discuss two alternative techniques for gaining renal access for PCNL under ultrasound guidance. We also describe a novel technique of using the puncture needle to reposition residual stone fragments to avoid additional tract dilation. With appropriate training, ultrasound-guided renal access for PCNL can lead to reduced radiation exposure, accurate renal access, and excellent stone-free success rates and clinical outcomes.

Adopting Ultrasound Guidance for Prone Percutaneous Nephrolithotomy: Evaluating the Learning Curve for the Experienced Surgeon

OBJECTIVES

To define the learning curve associated with adopting ultrasound guidance for prone percutaneous nephrolithotomy (PCNL) for the experienced surgeon.

METHODS

A prospective cohort study of consecutive patients undergoing PCNL with ultrasound guidance for renal tract access and dilation was performed. Clinical data reviewed included success in gaining renal access with ultrasound guidance, total fluoroscopic screening time, and radiation exposure dose. PCNL cases performed with fluoroscopic guidance matched for stone size served as control cases.

RESULTS

One hundred consecutive ultrasound-guided procedures performed by a single experienced endourologist were divided into five experience groups. Significant improvement in renal access success rate with ultrasound was seen after 20 cases (p < 0.05). Total fluoroscopic screening time, radiation exposure dose, and operative time were also statistically significantly improved over the study period. When compared with fluoroscopy-guided PCNL, significant decreases in total fluoroscopic screening time (33.4 ± 35.3 seconds vs 157.5 ± 84.9 seconds, p < 0.05) and radiation exposure (7.0 ± 8.7 mGy vs 47.8 ± 45.9 mGy, p < 0.05) were seen. No differences in complication rates were found.

CONCLUSIONS

Ultrasound-guided renal access for PCNL can be performed effectively after 20 cases. Transition to the use of ultrasound will quickly reduce radiation exposure for patients and intraoperative personnel.

A Novel method of ensuring safe and accurate dilatation during percutaneous nephrolithotomy

Objective:

To report our technique that helps locate the guidewire into the ureter enabling safe dilatation during PCNL.

Materials and Methods:

Cases in which the guidewire failed to pass into the ureter following successful puncture of the desired calyx were subjected to this technique. A second guidewire was passed through the outer sheath of a 9 Fr. metallic dilator cannula, passed over the first guidewire. The cannula and outer sheath were removed, followed by percutaneous passage of a 6/7.5 Fr ureteroscope between the two guidewires, monitoring its progress through both the endoscopic and fluoroscopic monitors. Once the stone was visualized in the calyx a guidewire was passed through the working channel and maneuvered past the stone into the pelvis and ureter under direct endoscopic vision. This was followed by routine tract dilatation.

Results:

This technique was employed in 85 out of 675 cases of PCNL carried out at our institute between Jan 2010 to June 2014. The mean time required for our technique, calculated from the point of introduction of the ureteroscope untill the successful passage of the guidewire down into the ureter was 95 seconds. There were no intraoperative or postoperative complications as a result of this technique. Guidewire could be successfully passed into the ureter in 82 out of 85 cases.

Conclusions:

Use of the ureteroscope introduced percutaneously through the puncture site in PCNL, is a safe and effective technique that helps in maneuvering the guidewire down into the ureter, which subsequently enables safe dilatation.

Ultrasound Guidance to Assist Percutaneous Nephrolithotomy Reduces Radiation Exposure in Obese Patients

OBJECTIVE

To evaluate the impact of body mass index (BMI) on perioperative outcomes and radiation exposure for ultrasound (US)-guided percutaneous nephrolithotomy (PCNL).

PATIENTS AND METHODS

Data were prospectively collected for consecutive patients who underwent PCNL at the University of California, San Francisco, from July 2013 to November 2015. Patients were divided into 3 groups according to their BMI: <25 (normal weight), 25-29.9 (overweight), and >30 (obese) kg/m². Perioperative outcomes were compared between patients who underwent US-guided vs fluoroscopy-guided PCNL.

RESULTS

One hundred thirty-five patients were enrolled; 93 cases were performed under US and 42 under fluoroscopic guidance. US successfully guided renal access in 76.9% of normal weight, 79.0% of overweight, and 45.7% of obese patients (P < .05). Mean fluoroscopic screening time and radiation exposure dose were reduced for US compared to fluoroscopy cases across all BMI categories (P < .05). As BMI increased, radiation exposure dose rose disproportionately faster compared to screening time (P < .001). No significant differences among the BMI groups were found with regard to complication rate, hospital stay, and stone-free status.

CONCLUSION

US-guided PCNL may be more difficult in obese patients, but with its use, the overweight and obese experience the largest absolute reduction in radiation exposure. Because these patients are inherently at greater risk for radiation exposure compared to normal weight patients, they may benefit the most from adoption of US for PCNL.

Ultrasound Guidance for Renal Tract Access and Dilation Reduces Radiation Exposure during Percutaneous Nephrolithotomy

Purposes. To present our series of 38 prone percutaneous nephrolithotomy procedures performed with renal access and tract dilation purely under ultrasound guidance and describe the benefits and challenges accompanying this approach. Methods. Thirty-eight consecutive patients presenting for percutaneous nephrolithotomy for renal stone removal were included in this prospective cohort study. Ultrasonographic imaging in the prone position was used to obtain percutaneous renal access and guide tract dilation. Fluoroscopic screening was used only for nephrostomy tube placement. Preoperative, intraoperative, and postoperative procedural and patient data were collected for analysis. Results. Mean age of patients was 52.7 ± 17.2 years. Forty-five percent of patients were male with mean BMI of 26.1 ± 7.3 and mean stone size of 27.2 ± 17.6 millimeters. Renal puncture was performed successfully with ultrasonographic guidance in all cases with mean puncture time of 135.4 ± 132.5 seconds. Mean dilation time was 11.5 ± 3.8 min and mean stone fragmentation time was 37.5 ± 29.0 min. Mean total operative time was 129.3 ± 41.1. No patients experienced any significant immediate postoperative complication. All patients were rendered stone-free and no additional secondary procedures were required. Conclusions. Ultrasound guidance for renal access and tract dilation in prone percutaneous nephrolithotomy is a feasible and effective technique. It can be performed safely with significantly reduced fluoroscopic radiation exposure to the patient, surgeon, and intraoperative personnel.

Direct Endoscopic Visualization Combined with Ultrasound Guided Access during Percutaneous Nephrolithotomy: A Feasibility Study and Comparison to a Conventional Cohort

PURPOSE

Percutaneous nephrolithotomy access may be technically challenging and result in significant radiation exposure. In an attempt to reduce percutaneous nephrolithotomy radiation exposure, a novel technique combining ultrasound and direct ureteroscopic visualization was developed and reviewed.

MATERIALS AND METHODS

Ureteroscopy without fluoroscopy was used to determine the optimal calyx for access, which was punctured with a Chiba needle under percutaneous ultrasound guidance. Next a wire was passed into the collecting system and ureteroscopically pulled into the ureter using a basket. Tract dilation and sheath and nephrostomy tube placement were performed under direct ureteroscopic visualization. Twenty consecutive patients undergoing this novel technique were reviewed and compared to 20 matched patients treated with conventional percutaneous nephrolithotomy. Mann-Whitney U and Pearson chi-square tests were used for comparisons with p <0.05 considered significant.

RESULTS

Using this novel technique mean fluoroscopy access time was 3.5 seconds (range 0 to 27.9) and mean total fluoroscopic time was 8.8 seconds (range 0 to 47.1). Mean operative time was 232 minutes (range 87 to 533), estimated blood loss was 111 ml, the stone-free rate was 65% and the complication rate was 25%. Compared to 20 matched conventional percutaneous nephrolithotomy cases, there was no difference in operative time (p=0.76), estimated blood loss (p=0.64), stone-free rate (p=0.50) or complications (p=1.00). However, the novel technique resulted in a significant reduction in fluoroscopy access time (3.5 vs 915.5 seconds, p <0.001) and total fluoroscopy time (8.8 vs 1,028.7 seconds, p <0.001).

CONCLUSIONS

This study demonstrates the feasibility of combined ultrasound and ureteroscopic assisted access for percutaneous nephrolithotomy. A greater than 99% reduction in fluoroscopy time was achieved using this technique.

Percutaneous stone removal: new approaches to access and imaging

Percutaneous renal access and removal of large renal calculi was first described nearly 40 years ago and has since become the gold standard in management of large and complex renal calculi. In this same time period, technological and medical advances have allowed this procedure to develop in improved efficacy and morbidity. The following review offers an update to new approaches to percutaneous renal access and imaging in the management of large and complex renal calculi.

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.

Factors affecting complications according to the modified Clavien classification in complete supine percutaneous nephrolithotomy

INTRODUCTION

An increase in percutaneous nephrolithotomy (PCNL) has been accompanied by an increase in complications. We identified the parameters affecting the severity of complications using the modified Clavien classification (MCC).

METHODS

From 2008 to 2013, 330 patients underwent complete supine PCNL using subcostal access, one-shot dilation, rigid nephroscopy, and pneumatic lithotripsy. We assessed the impact of the following factors on complication severity based on the MCC: age, gender, body mass index, hypertension, diabetes, previous stone surgery and extracorporeal shock wave lithotripsy, preoperative hemoglobin, renal dysfunction (creatinine >1.4 mg/dL), preoperative urinary tract infection, anatomic upper urinary tract abnormality (AUUTA), significant (moderate-severe) hydronephrosis, stone-related parameters (opacity, number, burden, location, staghorn, complex stones), anesthesia type, kidney side, imaging and calyx for access, tract number, tubeless approach, operative time, postoperative hemoglobin, and hemoglobin drop and stone-free results.

RESULTS

The complication rate was 19.7% (MCC: 0=80.3%, I=6.4%, II=11.2%, ≥III=2.1%). On univariate analyses, only the following factors affected MCC: gender, preoperative hemoglobin, AUUTA, significant hydronephrosis, imaging for access, calyx for access, tract number, postoperative hemoglobin, hemoglobin drop and stone-free result. Renal dysfunction was accompanied by higher complications, yet the results were not statistically significant. Multivariate logistic regression analysis demonstrated renal dysfunction, absence of significant hydronephrosis, AUUTA, multiple tracts, lower postoperative hemoglobin, and higher postoperative hemoglobin drop as the significant parameters which affected MCC and predicted higher grades. The paper's limitations include a low number of cases in the higher Clavien grades and some subgroups of variables, and not applying some techniques due to surgeon preference.

INTERPRETATION

Many of the complete supine PCNL complications were in the lower Clavien grades and major complications were uncommon. Renal dysfunction, AUUTA, significant hydronephrosis, tract number, postoperative hemoglobin, and hemoglobin drop were the only factors affecting MCC.

Real-time ultrasonography-guided percutaneous nephrolithotomy using SonixGPS navigation: clinical experience and practice in a single center in China

PURPOSE

To report our experience and evaluate the efficacy and safety of real-time ultrasonography-guided percutaneous nephrolithotomy (PCNL) using SonixGPS navigation in patients with kidney stones.

MATERIALS AND METHODS

From December 2012 to May 2013 in our hospital, the SonixGPS needle tracking system was used for real-time ultrasonography-guided puncture during PCNL in 25 patients with kidney stones. All the patients were under general anesthesia, in prone position; holmium laser lithotripsy was used in all patients after renal access was established. The time needed to perform puncture and the success rate of PCNL were recorded as two most important outcomes of this study.

RESULTS

All 25 patients underwent PCNL successfully with the help of SonixGPS navigation. The mean puncture time was 5.5 minutes (range 3-9 min), and the mean operative time was 74 minutes (range 30-100 min), respectively. The primary stone clearance rate of PCNL was 92% (23/25); no major intraoperative or postoperative complications occurred.

CONCLUSION

The results of this study indicate that puncture under SonixGPS navigation is safe and efficacious in PCNL, which may provides a new choice for PCNL.