A Comparative Study of Clinical Value of Single B-Mode Ultrasound Guidance and B-Mode Combined With Color Doppler Ultrasound Guidance in Mini-invasive Percutaneous Nephrolithotomy to Decrease Hemorrhagic Complications

A review of deep learning-based information fusion techniques for multimodal medical image classification

Multimodal medical imaging plays a pivotal role in clinical diagnosis and research, as it combines information from various imaging modalities to provide a more comprehensive understanding of the underlying pathology. Recently, deep learning-based multimodal fusion techniques have emerged as powerful tools for improving medical image classification. This review offers a thorough analysis of the developments in deep learning-based multimodal fusion for medical classification tasks. We explore the complementary relationships among prevalent clinical modalities and outline three main fusion schemes for multimodal classification networks: input fusion, intermediate fusion (encompassing single-level fusion, hierarchical fusion, and attention-based fusion), and output fusion. By evaluating the performance of these fusion techniques, we provide insight into the suitability of different network architectures for various multimodal fusion scenarios and application domains. Furthermore, we delve into challenges related to network architecture selection, handling incomplete multimodal data management, and the potential limitations of multimodal fusion. Finally, we spotlight the promising future of Transformer-based multimodal fusion techniques and give recommendations for future research in this rapidly evolving field.

Evaluation of the safety and efficiency of color Doppler ultrasound-guided percutaneous nephrolithotomy in clinical practice: results from a retrospective study

This study evaluated the clinical value of color Doppler ultrasound-guided percutaneous nephrolithotomy (PCNL) in avoiding bleeding caused by punctured blood vessels. Herein, we retrospectively included patients who underwent color Doppler ultrasound-guided PCNL or PCNL using the conventional channel technique from August 2018 to August 2022. The clinical characteristics of patients during surgery, complications, and hospital stay were recorded and compared. Overall, 228 patients were enrolled, with 126 patients (age, 47.6 ± 13.2 years; men: 57.14%) in the color Doppler ultrasound-guided PCNL group and 102 patients (age, 46.6 ± 12.3 years) in the B-mode ultrasound-guided puncture group. The total operation time (63.5 ± 15.5 vs. 61.3 ± 16.3 min, p = .5236) and stone clearance rate (86.50% vs. 83.33%, p = .7139) were similar between the two groups. However, the puncture time for the color Doppler ultrasound-guided PCNL group was longer than that for the B-mode ultrasound-guided puncture group (5.1 ± 2.3 vs. 2.6 ± 1.6 min, p = .0019). Moreover, the length of postoperative hospital stay in the color Doppler ultrasound-guided PCNL group reduced significantly by ∼1 day compared with that in the B-mode ultrasound-guided puncture group (4.5 ± 1.6 vs. 5.6 ± 2.1 days, p = .0087). The blood transfusion rate (1.58% vs. 4.9%, p = .0399), sedation-related adverse event rate (0.79% vs. 2.9%, p = .0332), perineal hematoma incidence (0% vs. 2.94%, p < .0001), and serum decreased hemoglobin levels (12.2 ± 9.7 vs. 23.5 ± 10.1 g/L, p < .001) after color Doppler ultrasound-guided PCNL were significantly lower than those after B-mode ultrasound-guided puncture. The stone clearance rate was similar between the two groups, with a similar operation time. Moreover, color Doppler ultrasound-guided PCNL shortened the postoperative hospital stay and decreased Hb levels, blood transfusion rate, and perineal hematoma incidence.

Application of ultrasound imaging in the treatment of urinary tract stones

Urinary tract stones are a common clinical condition that affect millions of individuals worldwide. The management of these stones has evolved significantly over the past 70 years, and ultrasound imaging has emerged as a valuable tool for diagnosis, treatment planning, and follow-up. This review aims to provide an overview of the application of ultrasound imaging in the treatment of urinary tract stones, highlighting its advantages, limitations, and current advancements in the field.

Presence of a Novel Anatomical Structure May Cause Bleeding When Using the Calyx Access in Mini-Percutaneous Nephrolithotomy

Background

Fused renal pyramid (FRP) is a kidney anatomical structure which was first identified by us. The vascular anatomy of FRP exhibits different from that of the normal renal pyramid (NRP), manifested by the distribution of the ectopic interlobar arteries in FRP. In this study, we analyzed the effect of FRPs on bleeding when using calyx access in mini-percutaneous nephrolithotomy (PCNL).

Patients and Methods

Overall, 633 patients who underwent ultrasound-guided single-tract mini-PCNL were divided into two groups according to the puncture method used: in group A, puncture was performed through the axial direction of the renal calyx, the line from the apex of the fornix to the center of the neck plane under B-mode ultrasound guidance; and in group B, Doppler ultrasound-guided axillary puncture through calyces corresponding to NRPs when the plane of renal column blood vessels on both sides was selected or calyx puncture through the hypovascular area of the FRPs. Relevant demographic and clinical data were retrospectively analyzed.

Results

The two groups exhibited similar baseline characteristics. No significant differences were found in hemoglobin reduction, puncture site, tract size, postoperative creatinine level, or stone-free rate between the two groups (P > 0.05). Blood transfusion and embolization rates in group B were significantly lower than those in group A (P = 0.03 and 0.045, respectively). No differences were found between the two groups in terms of persistent pain, hydrothorax, fever, subcapsular hematoma, and urosepsis (P > 0.05). The overall complication rate was not significantly different between the two groups (P = 0.505).

Conclusions

FRP is a non-negligible anatomical structure that may cause hemorrhage when using calyx access. Doppler ultrasound can identify ectopic blood vessels in FRPs to reduce bleeding during calyx access in mini-PCNL procedures.

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.

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.

Deep-learning-aided forward optical coherence tomography endoscope for percutaneous nephrostomy guidance

Percutaneous renal access is the critical initial step in many medical settings. In order to obtain the best surgical outcome with minimum patient morbidity, an improved method for access to the renal calyx is needed. In our study, we built a forward-view optical coherence tomography (OCT) endoscopic system for percutaneous nephrostomy (PCN) guidance. Porcine kidneys were imaged in our experiment to demonstrate the feasibility of the imaging system. Three tissue types of porcine kidneys (renal cortex, medulla, and calyx) can be clearly distinguished due to the morphological and tissue differences from the OCT endoscopic images. To further improve the guidance efficacy and reduce the learning burden of the clinical doctors, a deep-learning-based computer aided diagnosis platform was developed to automatically classify the OCT images by the renal tissue types. Convolutional neural networks (CNN) were developed with labeled OCT images based on the ResNet34, MobileNetv2 and ResNet50 architectures. Nested cross-validation and testing was used to benchmark the classification performance with uncertainty quantification over 10 kidneys, which demonstrated robust performance over substantial biological variability among kidneys. ResNet50-based CNN models achieved an average classification accuracy of 82.6%±3.0%. The classification precisions were 79%±4% for cortex, 85%±6% for medulla, and 91%±5% for calyx and the classification recalls were 68%±11% for cortex, 91%±4% for medulla, and 89%±3% for calyx. Interpretation of the CNN predictions showed the discriminative characteristics in the OCT images of the three renal tissue types. The results validated the technical feasibility of using this novel imaging platform to automatically recognize the images of renal tissue structures ahead of the PCN needle in PCN surgery.

Reducing postoperative morbidity of mini-invasive percutaneous nephrolithotomy: Would it help if blood vessels are left unharmed during puncture? A CONSORT-prospective randomized trial

BACKGROUND

The aim of this study was to provide a randomized controlled trial comparing single B-mode ultrasound guidance and color doppler ultrasound guidance in minimally invasive percutaneous nephrolithotomy.

METHODS

Three hundred patients with renal calculus were prospectively randomly assigned into 2 groups. In group 1 (150 patients), minimally invasive percutaneous nephrolithotomy (m-PCNL) were managed with single B-mode ultrasound guidance; In group 2 (150 patients), m-PCNL were managed with color Doppler ultrasound guidance and a needle bracket in order to guide placement at a target location beneath the skin. The characteristics of patients, operation, complications and prognosis, including body temperature, urine culture, and hematologic tests after the operation were recorded and compared.

RESULTS

Our vessel-sparing technique showed a statistically significant decrease in hemoglobin drop, postoperative procalcitonin values, the frequency of postoperative fever, systemic inflammatory response syndrome, and urosepsis (P < .05).

CONCLUSION

Using color Doppler ultrasound in real time and a needle bracket to detect and avoid main renal blood vessels decreased incidences of hemorrhagic complications and postoperative infection.

Wideband Doppler Ultrasound-guided Mini-endoscopic Combined Intrarenal Surgery as an Effective and Safe Procedure for Management of Large Renal Stones: A Preliminary Report

OBJECTIVE

To evaluate the efficacy and safety of wideband Doppler ultrasound-guided mini-endoscopic combined intrarenal surgery (mini-ECIRS) for large renal stones.

MATERIALS AND METHODS

This study included 41 patients with large renal stones (>30 mm) treated by mini-ECIRS using a retrograde flexible ureteroscope and miniature nephroscope by wideband Doppler ultrasound guidance in the modified Valdivia position from January 2013 to September 2015. Surgical parameters, including the stone-free rate, operative time, complications (especially hemorrhagic complications), and hemoglobin drop were recorded and analyzed. Univariate analysis was performed to identify risk factors for a hemoglobin drop of ≥1 g/dL.

RESULTS

The mean stone size, including staghorn calculi in 41.4% of cases, was 45.5 ± 14.7 mm. Percutaneous access into the calices using wideband Doppler ultrasound was successful in all cases. The mean total operative time was 158.4 ± 51.3 minutes. The mean mini-ECIRS time (from first percutaneous puncture to end of procedure) was 106.2 ± 36.0 minutes. The initial stone-free rate was 73.2% (n = 30). The final stone-free rate after auxiliary treatment was 97.5% (n = 40). The mean hemoglobin drop was 0.54 ± 0.65 g/dL. Three (7.3%) postoperative modified Clavien grade II complications occurred. Univariate analysis revealed no significant risk factors for a hemoglobin drop of ≥1 g/dL.

CONCLUSION

Wideband Doppler ultrasound-guided renal puncture is safe and feasible. Wideband Doppler ultrasound-guided mini-ECIRS is a beneficial, versatile, and safe treatment option for management of large renal stones of >30 mm.

Value of CT angiography in reducing the risk of hemorrhage associated with mini-percutaneous nephrolithotomy

Purpose:

To evaluate the clinical value of computed tomography angiography (CTA) in reducing the risk of hemorrhage associated with mini-percutaneous nephrolithotomy (PCNL).

Materials and Methods:

A total of 158 patients with renal or ureter stones who had undergone mini-percutaneous nephrolithotomy were retrospectively enrolled into this study from May of 2011 to April of 2014. Group 1 (65 patients) underwent computed tomography angiography, and Group 2 (93 patients) underwent non-contrast CT. The clinical characteristics of the patients and hemorrhagic complications were recorded. The hematologic complications (transfusion rate, and preoperative and postoperative hemoglobin values) were assessed.

Results:

There were no statistically significant differences in age, body mass index(BMI), stone diameter, operative time, stone-free rate, and hospital stay between the 2 groups. In group 2, 1 patient (1.1%) developed a renal arteriovenous fistula and was treated with embolus therapy. In addition, Group 2 showed significantly drop in hemoglobin (3.6 g/dL vs. 2.4 g/dL, respectively; P <0.001) and more transfusions (9.7% vs. 1.5%, respectively; P <0.05) compared with Group 1.

Conclusion:

The study showed that patients who underwent computed tomography angiography prior to percutaneous nephrolithotomy had lower drop of hemoglobin and needed less transfusions. These findings may suggest that the use of computed tomography angiography may reduce the risk of bleeding during percutaneous nephrolithotomy.

[Comparison of laparoscopic pyelolithotomy and percutaneous nephrolithotomy for renal pelvic stones larger than 2.5 cm]

OBJECTIVE

To compare the safety, efficacy and complications of laparoscopic pyelolithotomy (LPL) and percutaneous nephrolithotomy (PCNL) for treatment of renal pelvic stones larger than 2.5 cm.

METHODS

From 2011 to 2016, 32 patients underwent LPL and another 32 patients received PCNL for renal pelvic stones larger than 2.5 cm. The baseline characteristics of the patients, stone size, mean operative time, estimated blood loss, postoperative hospital stay, stone-free rate, postoperative analgesia, blood transfusion, and the intraoperative, early postoperative and long-term complications were compared between the two groups.

RESULTS

The baseline characteristics and stone size were comparable between the two groups. The mean operative time of LPL and PCNL was 117∓23.12 and 118.16∓25.45 min, respectively (P>0.05). The two groups showed significant differences in the mean estimated blood loss (63∓11.25 vs 122∓27.78 mL, P<0.01) and blood transfusion rate (0 vs 6.2%, P<0.01) but not in postoperative hospital stay (4.5∓1.34 vs 4.8∓2.2 days, P>0.05), stone-free rate (93.1% vs 87.5%, P>0.05) or the postoperative analgesia time (1.7∓0.5 and 1.9∓0.6 days, P>0.05). The incidence of intraoperative complications were significant lower in LPL group than in PCNL group (6.2% vs 25.0%, P<0.01), but the incidences of early postoperative complications (25.0% vs 34.4%, P>0.05) and long-term postoperative complications (9.4% vs 12.5%, P>0.05) were similar between them.

CONCLUSION

PCNL is the standard treatment for pelvic stones larger than 2.5 cm, but for urologists experienced with laparoscopic technique, LPL provides a feasible and safe option for management of such cases.

Percutaneous nephrolithotomy guided solely by ultrasonography: a 5-year study of >700 cases

OBJECTIVE

To evaluate the safety and efficacy of percutaneous nephrolithotomy (PCNL) solely guided by ultrasonography (US).

PATIENTS AND METHODS

From May 2007 to July 2012, 705 24-F-tract PCNL procedures were performed (679 patients, of whom 26 had bilateral stones). Calyceal puncture and dilatation were performed under US guidance in all cases. The procedure was evaluated for access success, length of postoperative hospital stay, complications (modified Clavien system), stone clearance and the need for auxiliary treatments.

RESULTS

The mean (sd) operating time was 66 (25) min, with a mean (sd) postoperative hospital stay of 3.98 (1.34) days. The patients experienced a mean (sd) haemoglobin level decrease of 2.24 (2.02) g/day and the overall stone-free rate at 4 weeks after surgery was 92.6% in patients with a single calculus and 82.9% in patients with staghorn or multiple calculi. Auxiliary treatments, including shockwave lithotripsy in 52 patients, re-PCNL in 41 patients and ureteroscopy in 18 patients, were performed 1 week after the primary procedure in 111 (15.7%) cases for residual stones >4 mm in size. The sensitivities of intra-operative US-guidance and flexible nephroscopy for detecting significant residual stones and clinically insignificant residual fragments were 95.3 and 89.1%, respectively. There were 94 grade 1 (13.3%), 17 grade 2 (2.4%), and two grade 3 (0.3%) complications, but there were no grade 4 or 5 complications.

CONCLUSION

Total US-guided PCNL is safe and convenient, and may be performed without any major complications and with the advantage of preventing radiation hazards and damage to adjacent organs.

Supine lithotomy versus prone position in minimally invasive percutaneous nephrolithotomy for upper urinary tract calculi

OBJECTIVE

To compare operative time, safety and effectiveness of minimally invasive percutaneous nephrolithotomy (MPCNL) in the supine lithotomy versus prone position.

METHODS

Between January 2008 and December 2010, a total of 109 consecutive patients with upper urinary tract calculi were enrolled and randomly divided into group A (53 patients, supine lithotomy position) and group B (56 patients, prone position). The MPCNL procedures were performed under the guidance of real-time grayscale ultrasound system. The preoperative characteristics, intraoperative and postoperative parameters were analyzed and compared.

RESULTS

All patients were successfully operated. There was no significant difference between the two groups in stone-free rate (group A 90.1 vs. group B 87.5%, p = 0.45), mean blood loss, number of access tracts, calyx puncture, mean hospital stay (group A 6 ± 1.1 vs. group B 6 ± 1.5 days, p = 0.38) and complications. But the operative time was significantly shortened in supine lithotomy position (group A 56 ± 15 vs. group B 86 ± 23 min, p < 0.001).

CONCLUSIONS

The effectiveness and safety of the supine lithotomy position for MPCNL were similar to the prone position. However, the supine lithotomy position has an important advantage of reducing the operative time. The supine lithotomy position could be a good choice to perform MPCNL.

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

Percutaneous renal access is a common procedure in urologic practice. The main indications are drainage of an obstructed and hydronephrotic kidney and antegrade renal access prior to percutaneous renal surgeries such as percutaneous nephrolithotomy (PCNL) and percutaneous endopyelotomy (EP). The contraindications for this technique are patients with history of allergy to topical or local anesthesia and patients with coagulopathy. The creation of a percutaneous tract into the renal collecting system is one of the important steps for percutaneous renal access. This step usually requires imaging. The advantages and disadvantages of each modality of image guidance are controversial. We performed a structured review using the terms: Percutaneous nephrostomy, guidance, fluoroscopy, ultrasonography, computed tomography (CT) scan, and magnetic resonance imaging (MRI). The outcomes are discussed.

Impact of percutaneous renal access technique on outcomes of percutaneous nephrolithotomy

BACKGROUND AND PURPOSE

Percutaneous nephrolithotomy (PCNL) is regarded as the gold standard for the treatment of patients with renal stones larger than 2 cm in diameter. Creating a percutaneous renal access is the initial and probably the most important step in performing a PCNL. Two primary methods of obtaining proper percutaneous renal access under fluoroscopic guidance are described: The "triangulation" and the "eye of the needle" techniques. In this article, we compare these two techniques in terms of success and complication rates.

PATIENTS AND METHODS

From October 2010 to May 2011, 80 patients with simple renal stones were prospectively randomized into two groups according to the percutaneous renal access technique used for PCNL. Patients in group 1 (n=40) were assigned to the eye of the needle technique, and patients in group 2 (n=40) were assigned to the triangulation method. Patients needing multiple access points were excluded from the study. The preoperative, operative, and postoperative follow-up findings were thereafter analyzed and compared.

RESULTS

No significant difference between the two groups was detected in terms of patient demographics (mean patient age, body mass index, stone size, or stone location). The operation time, fluoroscopic screening time (FST), and duration of hospitalization were similar in both groups (P=0.52, P=0.32, P=0.26, respectively). Patients in group 1 had a larger drop in hematocrit postoperatively than patients in group 2 (7.6 ± 3.7 vs 4.8 ± 2.1, P=0.001). The blood transfusion rate (7.5%) was similar in both groups, however. Although the complication rate was higher in group 1 than group 2, no significant difference was detected (20% vs 15%, P=0.76).

CONCLUSIONS

The present study demonstrates that PCNL can be performed safely using two different percutaneous access techniques. The two techniques studied in this trial had similar FSTs, operation and hospitalization times, success rates, and complication rates.

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.