Laser-guided percutaneous kidney access with the Uro Dyna-CT: first experience of three-dimensional puncture planning with an ex vivo model

Robotic-assisted versus manual Uro Dyna-CT-guided puncture in an ex-vivo kidney phantom

INTRODUCTION AND OBJECTIVES

Challenging percutaneous renal punctures to gain access to the kidney requiring guidance by cross-sectional imaging. To test the feasibility of robotic-assisted CT-guided punctures (RP) and compare them with manual laser-guided punctures (MP) with Uro Dyna-CT (Siemens Healthcare Solutions, Erlangen, Germany).

MATERIAL AND METHODS

The silicon kidney phantom contained target lesions of three sizes. RP were performed using a robotic assistance system (guidoo, BEC GmbH, Pfullingen, Germany) with a robotic arm (LBR med R800, KUKA AG, Augsburg, Germany) and a navigation software with a cone-beam-CT Artis zeego (Siemens Healthcare GmbH, Erlangen, Germany). MP were performed using the syngo iGuide Uro-Dyna Artis Zee Ceiling CT (Siemens Healthcare Solutions). Three urologists with varying experience performed 20 punctures each. Success rate, puncture accuracy, puncture planning time (PPT), and needle placement time (NPT) were measured and compared with ANOVA and Chi-Square Test.

RESULTS

One hundred eighteen punctures with a success rate of 100% for RP and 78% for MP were included. Puncture accuracy was significantly higher for RP. PPT (RP: 238 ± 90s, MP: 104 ± 21s) and NPT (RP: 128 ± 40s, MP: 81 ± 18s) were significantly longer for RP. The outcome variables did not differ significantly with regard to levels of investigators' experience.

CONCLUSION

The accuracy of RP was superior to that of MP. This study paves the way for first in-human application of this robotic puncture system.

Prevalence of the Retro-Renal Colon: A Systematic Review and Meta-Analysis with Implications for Percutaneous Nephrolithotomy

BACKGROUND

This systematic review and meta-analysis aims to determine the prevalence of the retrorenal colon (RRC) and its implications in percutaneous nephrolithotomy with the overall objective of promoting the prevention of associated iatrogenic complications.

METHODS

A systematic search of literature was conducted on the electronic databases PubMed, ScienceDirect, and Hinari to identify studies eligible for inclusion. Search results were screened by title and abstract, and those potentially relevant were evaluated by full text. Studies were deemed eligible for inclusion if they reported clear extractable data regarding the prevalence of the retro-renal colon. A meta-analysis was completed using MetaX1 to calculate the pooled prevalence of the retro-renal colon. Sub-group analysis was performed based on geographical regions from which the studies originated, imaging modality, and patient position.

RESULTS

174 records were screened and a total of 10 records included in the analysis with retrospective cohort studies being the most common study design. A male predominance was seen in most sample sizes that had reported data on gender demographics ranging from 41.5-62%. The most common imaging modality utilized was computerized tomography (CT) scan followed by ultrasound. The range of the unweighted prevalence of retro-renal colon across all studies that had absolute numbers reported was from 3.5-25%. One of the studies reported a colonic perforation rate of 0.3% in patients without CT images.

CONCLUSION

The retro-renal colon is a relatively common finding with observed preponderance to females and left lateralization. The presence of RRC increases the likelihood of colon perforations while gaining percutaneous access to the kidney. Pre-procedural imaging can help detect its presence and choose an appropriate route of entry. USG and CT have both been found useful as a modality to pick up RRC.

Direct puncture the superior ophthalmic vein guiding by Dyna-CT to obliterating a traumatic carotid-cavernous sinus fistula: A case report and literature review

RATIONALE

Traumatic carotid-cavernous sinus fistula (TCCF) is a pathological shunt between the carotid arteries and cavernous sinus due to trauma. Imaging-guided (e.g., ultrasonic image and fluoroscopic roadmap image) direct puncture of the superior ophthalmic vein (SOV) for embolization of TCCF has been previously described in other studies.

PATIENT CONCERNS AND DIAGNOSIS

We report a case of TCCF in a 58-years-old male patient who was admitted to our hospital with a sustained head injury after falling from a high platform, resulting in rapidly progressive swelling, pain, diminishing vision for more than 6 months, and blindness in his left eye for 1 month.

INTERVENTIONS AND OUTCOMES

The patient underwent digital subtraction angiography and endovascular embolization. After the failure of super-selection of the left cavernous sinus, an alternative approach to obliterating the TCCF by puncturing the SOV is directly guided by Dyna-CT. After embolization, the patient's clinical symptoms gradually disappeared and discharged from the hospital 5 days later. No recurrence or complications occurred during follow-up for 1 year.

CONCLUSION

This case illustrates that direct puncture of the SOV guided by Dyna-CT as an alternative approach to embolization of TCCF is safe, effective, and feasible.

Querying the significance of patient position during computerized tomography on the reliability of pre-percutaneous nephrolithotomy planning

BACKGROUND

Computerized tomography (CT) is considered indispensable in percutaneous nephrolithotomy (PCNL) planning. We aimed to define the reliability of pre-PCNL CT for planning renal access by assessing renal positional changes between supine and prone CTs.

SUBJECTS AND METHODS

CT urographies (CTU) of 30 consecutive patients were reviewed for distances upper pole (UP)-diaphragm, UP-diaphragm attachment, renal pelvis (RP)-lateral body wall, RP- posterior body wall, and lower pole (LP)- anterior-superior iliac spine (ASIS). The posterior and lateral renal axes angles were also calculated.

RESULTS

The most consistent overall movement in transition from prone to supine was backward rotation, as demonstrated by a decrease in distance UP-posterior body wall (p = 0.010) and increase in the posterior renal angle (p < 0.0001). This finding correlated with the patient's body mass index (BMI) (p = 0.029). The left kidney was more mobile than the right one, moving significantly for five of the measured parameters compared to the right kidney which moved significantly for only two parameters. The UP-diaphragm distance of the left kidney correlated with age (p = 0.014), the RP-lateral wall distance correlated with previous abdominal surgery (p = 0.006), and the RP-posterior wall distance with BMI (p = 0.017). On the right, the UP-diaphragm distance correlated with gender (p = 0.002) and the lateral renal rotation was smaller (p = 0.046).

CONCLUSIONS

Kidneys present significant mobility between supine and prone positions. CT assessment should be performed in the position expected during surgery and should be interpreted with caution, while a real-time imaging modality should be used in the operating room.

Percutaneous Kidney Puncture with Three-dimensional Mixed-reality Hologram Guidance: From Preoperative Planning to Intraoperative Navigation

BACKGROUND

Despite technical and technological innovations, percutaneous puncture still represents the most challenging step when performing percutaneous nephrolithotomy. This maneuver is characterized by the steepest learning curve and a risk of injuring surrounding organs and kidney damage.

OBJECTIVE

To evaluate the feasibility of three-dimensional mixed reality (3D MR) holograms in establishing the access point and guiding the needle during percutaneous kidney puncture.

DESIGN, SETTING, AND PARTICIPANTS

This prospective study included ten patients who underwent 3D MR endoscopic combined intrarenal surgery (ECIRS) for kidney stones from July 2019 to January 2020. A retrospective series of patients who underwent a standard procedure were selected for matched pair analysis.

SURGICAL PROCEDURE

For patients who underwent 3D MR ECIRS, holograms were overlapped on the real anatomy to guide the surgeon during percutaneous puncture. In the standard group, the procedures were only guided by ultrasound and fluoroscopy.

MEASUREMENTS

Differences in preoperative and postoperative patient characteristics between the groups were tested using a χ² test and a Kruskal-Wallis test for categorical and continuous variables, respectively. Results are reported as the median and interquartile range for continuous variables and as the frequency and percentage for categorical variables.

RESULTS AND LIMITATIONS

Ten patients underwent 3D MR ECIRS. In all cases, the inferior calyx was punctured correctly, as planned using the overlapping hologram. The median puncture and radiation exposure times were 27 min and 120 s, respectively. No intraoperative or major postoperative complications occurred. Matched pair analysis with the standard ECIRS group revealed a significantly shorter radiation exposure time for the 3D MR group (p < 0.001) even though the puncture time was longer in comparison to the standard group (p < 0.001). Finally, use of 3D MR led to a higher success rate for renal puncture at the first attempt (100% vs 50%; p = 0.032). The main limitations of the study are the small sample size and manual overlapping of the rigid hologram models.

CONCLUSIONS

Our experience demonstrates that 3D MR guidance for renal puncture is feasible and safe. The procedure proved to be effective, with the inferior calyx correctly punctured in all cases, and was associated with a low intraoperative radiation exposure time because of the MR guidance.

PATIENT SUMMARY

Three-dimensional virtual models visualized as holograms and intraoperatively overlapped on the patient's real anatomy seem to be a valid new tool for guiding puncture of the kidney through the skin for minimally invasive treatment.

Percutaneous puncture during PCNL: new perspective for the future with virtual imaging guidance

CONTEXT

Large and complex renal stones are usually treated with percutaneous nephrolithotomy (PCNL). One of the crucial steps in this procedure is the access to the collecting system with the percutaneous puncture and this maneuver leads to a risk of vascular and neighboring organs' injury. In the last years, the application of virtual image-guided surgery has gained wide diffusion even in this specific field.

OBJECTIVES

To provide a short overview of the most recent evidence on current applications of virtual imaging guidance for PCNL.

EVIDENCE ACQUISITION

A non-systematic review of the literature was performed. Medline, PubMed, the Cochrane Database and Embase were screened for studies regarding the use virtual imaging guidance for PCNL.

EVIDENCE SYNTHESIS

3D virtual navigation technology for PCNL was first used in urology with the purpose of surgical training and surgical planning; subsequently, the field of surgical navigation with different modalities (from cognitive to augmented reality or mixed reality) had been explored. Finally, anecdotal preliminary experiences explored the potential application of artificial intelligence guidance for percutaneous puncture.

CONCLUSION

Nowadays, many experiences proved the potential benefit of virtual guidance for surgical simulation and training. Focusing on surgery, this tool revealed to be useful both for surgical planning, allowed to achieve a better surgical performance, and for surgical navigation by using augmented reality and mixed reality systems aimed to assist the surgeon in real time during the intervention.

[Navigation systems for the percutaneous access to the kidney]

BACKGROUND

Percutaneous access to the renal pelvis still remains the most difficult step before nephrolitholapaxy (PCNL). New imaging techniques, such as 3D imaging and various navigation instruments such as electromagnetic, sonographic, CT-controlled and marker-based/iPAD try to simplify this step and reduce complications.

OBJECTIVES

In this review, various new techniques for puncturing the renal collecting system are presented and their advantages and disadvantages are evaluated.

MATERIALS AND METHODS

A systematic literature search was carried out in MEDLINE, whereby only puncture techniques that have already been evaluated in clinical studies were included.

RESULTS

Five different navigation methods for puncturing the renal pelvis before PCNL were found.

CONCLUSION

Intraoperative navigation can be useful when puncturing the collecting system. The combination of ultrasound and fluoroscopy currently remains the gold standard. However, there is still a need for further, primarily clinical, prospective studies to determine which new imaging technology and navigation systems will prevail and thus facilitate the access route to the kidney, especially in the case of special anatomical conditions.

Preoperative imaging in staghorn calculi, planning and decision making in management of staghorn calculi

Objective

Staghorn calculi present a particular and challenging entity of stone morphology. Treatment is associated with lower stone-free rates and higher complication rates compared to non-staghorn stones. In this review we looked for the most relevant data on preoperative imaging and access planning to help decision making for percutaneous surgery with this complex condition.

Methods

We conducted a PubMed search of publications in the past 2 decades that include relevant information on the planning for management of staghorn stones. Non-contrast computerized tomography (NCCT) is indeed the standard imaging tool for percutaneous nephrolithotomy (PCNL); additional tools such as three-dimensional computed tomography (CT) reconstruction of the staghorn calculus may help plan access in complex cases. Ultrasound guided percutaneous access may be considered for staghorn stones when planning upper pole access in kidney malposition or complex intrarenal anatomy or with complex body habitus. Wideband doppler ultrasound and real-time virtual sonography can assist. New technologies to improve kidney access such as Uro Dyna-CT or electromagnetic sensor have been reported, but have not shown utilization in staghorn cases. Staghorn morphometry-based prediction algorithms may predict the number of tract(s) and stage(s) for PCNL monotherapy. Lower pole access can be equally effective as upper pole when planning for staghorn and complex stones, with significantly less complications rate; Stone-Tract length-Obstruction-Number of involved calyces-Essence of stone density (STONE) nephrolithometry seems to be the best system to predict outcomes of PCNL in staghorn cases. There is a growing trend of endoscopic combined intrarenal surgery (ECIRS) in concordance with PCNL to treat larger stones. Conservative management of staghorn calculi is an undesired option, but can be an alternative for a carefully selected group of high-risk patients.

Conclusion

Staghorn stones may lead to deterioration of renal function and life-threatening urosepsis. This entity should be managed aggressively with planning ahead for surgery using the different tools available as the cornerstone for a successful outcome.

Extracorporeal shock-wave lithotripsy: is it still valid in the era of robotic endourology? Can it be more efficient?

PURPOSE OF REVIEW

The aim of the article is to evaluate the actual role of extracorporeal shock-wave lithotripsy (ESWL) in the management of urolithiasis based on the new developments of flexible ureterorenoscopy (FURS) and percutaneous nephrolithotomy (PCNL).

RECENT FINDINGS

In Western Europe, there is a significant change of techniques used for treatment of renal stones with an increase of FURS and a decrease of ESWL. The reasons for this include the change of indications, technical improvement of the endourologic armamentarium, including robotic assistance. Mostly relevant is the introduction of digital reusable and single-use flexible ureterorenoscopes, whereas micro-PCNL has been abandoned. Some companies have stopped production of lithotripters and novel ideas to improve the efficacy of shock waves have not been implemented in the actual systems. Promising shock-wave technologies include the use of burst-shock-wave lithotripsy (SWL) or high-frequent ESWL. The main advantage would be the very fast pulverization of the stone as shown in in-vitro models.

SUMMARY

The role of ESWL in the management of urolithiasis is decreasing, whereas FURS is constantly progressing. Quality and safety of intracorporeal shock-wave lithotripsy using holmium:YAG-laser under endoscopic control clearly outweighs the advantages of noninvasive ESWL. To regain ground, new technologies like burst-SWL or high-frequent ESWL have to be implemented in new systems.

Percutaneous kidney stone surgery and radiation exposure: A review

During the past 3 decades, radiation exposure (RE) has increased drastically among patients undergoing percutaneous nephrolithotomy (PCNL), thus potentially causing new cases of cancer each year. The effective dose received by patients comes from pre- and post-operative computed tomography (CT) and intraoperative fluoroscopy (FL). We reviewed literature to find novel techniques and approaches that help to decrease RE of patients and personnel. We performed PubMed search using keywords percutaneous nephrolithotomy, intraoperative fluoroscopy, radiation exposure, imaging, percutaneous access, ultrasound, computed tomography, endoscopy, reconstruction, innovations, and augmented reality. Forty-four relevant articles were included in this review. As much as 20% of patients with first diagnosed urolithiasis exceed background RE level almost 17-fold. For diagnosing purposes using low-dose and ultra-low-dose CT, as well as low-dose dual energy scan protocols can be efficient ways to decrease RE while maintaining decent accuracy. Patients with urinary stones can be effectively monitored with digital tomosynthesis, ultrasound alone or ultrasound combined with plain film of the abdomen. Percutaneous access (PCA) into the kidney can be performed with reduced or even no RE, using novel PCA methods. REs from conventional imaging techniques during diagnosis and treatment increase probability of non-stochastic radiation effects. Urologists should be aware of protocols that decrease RE from CT and FL in diagnosis and management of urinary stones. Consideration of recently developed imaging modalities and PCA techniques will also aid in adherence to the “as low as reasonably achievable” principle.

iPad-assisted percutaneous nephrolithotomy (PCNL): a matched pair analysis compared to standard PCNL

PURPOSE

To compare iPad-assisted (Apple Inc., Cupertino, USA) percutaneous access to the kidney to the standard puncturing technique for percutaneous nephrolithotomy (PCNL).

METHODS

For the iPad-assisted PCNL, a computed tomography is performed prior to surgery, using fiducial radiopaque markers. The important anatomical structures (i.e. kidney, stones) are segmented using specific software enabling the superimposition of images semi-transparently on the iPad by marker-based navigation. Twenty-two patients underwent an iPad-assisted percutaneous puncture of the kidney for PCNL. Twenty-two patients of the clinical database from the Urological Department SLK Hospital Heilbronn, who underwent the standard puncturing technique, were matched to these patients. Matching criteria were age, gender, stone volume, body mass index, stone site and the absence of anatomical variation. Puncture time, radiation exposure and number of attempts for a successful puncture were evaluated. All procedures were performed by two experienced urologists. The standard puncturing method consisted of a combination of ultrasound and fluoroscopy guidance. Chi-square and t test were used to ensure that there was no difference in the matching criteria between the groups. To compare the two methods, U test, Kruskal-Wallis and Chi-square test were used.

RESULTS

Examination of radiation exposure showed a significant difference between the two groups in favour of the standard puncturing method (p < 0.01) and puncture time (p = 0.01). However, there was no significant difference in puncturing attempts (p = 0.45).

CONCLUSION

The iPad-assisted navigation, with the objective being to puncture the renal collecting system, represents a new technique (IDEAL criteria 2b), which proved to be applicable in clinical practice, but still has potential for technical improvement.

Feasibility of a novel technique using 3-dimensional modeling and augmented reality for access during percutaneous nephrolithotomy in two different ex-vivo models

PURPOSE

We describe a novel technique that uses mathematical calculation software, 3-dimensional (3D) modeling and augmented reality (AR) technology for access during percutaneous nephrolithotomy (PCNL) and report our first preliminary results in two different ex-vivo models.

METHODS

Novel software was created in order to calculate access point and angle by using pre-operative computed tomography (CT) obtained in 50 patients. Two scans, 27 s and 10 min after injection of contrast agent, were taken in prone PCNL position. By using DICOM objects, mathematical and software functions were developed to measure distance of stone from reference electrodes. Vectoral 3D modeling was performed to calculate the access point, direction angle and access angle. With specific programs and AR, 3D modeling was placed virtually onto real object, and the calculated access point and an access needle according to the calculated direction angle and access angle were displayed virtually on the object on the screen of tablet.

RESULTS

The system was tested on two different models-a stone placed in a gel cushion, and a stone inserted in a bovine kidney that was placed in a chicken-for twice, and correct access point and angle were achieved at every time. Accuracy of insertion of needle was checked by feeling crepitation on stone surface and observing tip of needle touching stone in a control CT scan.

CONCLUSIONS

This novel device, which uses software-based mathematical calculation, 3D modeling and AR, seems to ensure a correct access point and angle for PCNL. Further research is required to test its accuracy and safety in humans.

Use of the Uro Dyna-CT in endourology - the new frontier

We describe the use of the Uro Dyna-CT, an imaging system used in the operating room that produces real-time three-dimensional (3D) imaging and cross-sectional image reconstructions similar to an intraoperative computerized tomography, during a percutaneous nephrolithotomy and a contralateral flexible ureteroscopy in a complete supine position. A 65 year-old female patient had an incomplete calyceal staghorn stone in the right kidney and a 10mm in the left one. The procedure was uneventful and the intraoperative use of the Uro Dyna-CT identified 2 residual stones that were not found by digital fluoroscopy and flexible nephroscopy at the end of surgery, helping us to render the patient stone-free in one procedure, which was confirmed by a postoperative CT scan. Prospective studies will define the real role of the Uro Dyna-CT for endourological procedures, but its use seems to be a very promising tool for improving stone free rates and decreasing auxiliary procedures, especially for complex cases.

Feasibility of laser-guided percutaneous pedicle screw placement in the lumbar spine using a hybrid-OR

PURPOSE

Innovations in intraoperative imaging lead to major changes in orthopaedic surgery. In our setting, a 3D flat-panel c-arm (Artis zeego) is mounted on a robotic arm offering an integrated aiming tool (Syngo iGuide). Our aim was to investigate the feasibility of Syngo iGuide for pedicle screw placement in comparison with fluoroscopic screw implantation.

METHODS

In 10 lumbar models, 100 screws were implanted. In 5 models, a standard fluoroscopic technique was used. Syngo iGuide was used in all other models. Afterwards, CT-scans were performed and screw accuracy was investigated.

RESULTS

The procedure time for the new technique was significantly longer in comparison with the standard technique. The post-operative CT showed the same accuracy in both groups.

CONCLUSIONS

Syngo iGuide proofed feasible for percutaneous implantation of pedicle screws in anatomic models. Syngo iGuide can be a help for screw implantation in difficult anatomic regions without the need of an additional navigation system.

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.

Computed tomography-guided biopsies in children: accuracy, efficiency and dose usage

Background

Computed-tomography-guided interventions are attractive for tissue sampling of paediatric tumor lesions; however, it comes with exposure to ionizing radiation. The aim of this study was to analyse the radiation dose, accuracy and speed of CT-guided interventions in paediatric patient cohort.

Methods

We retrospectively reviewed CT-guided interventions over a 10 -year period in 65 children. The intervention site consisted of bones in 38, chest (lung) in 15 and abdomen (liver, lymph nodes) in 12 cases. Radiation dose and duration of the procedures were analysed. The statistical analysis was performed using dedicated statistical software (BiAS 8.3.6 software, Epsilon Verlag, North Hasted).

Results

All interventions were performed successfully. Mean target access path to lesion within the patients was 6.0 cm (min 3.5 cm, max 11.2 cm). Time duration to complete intervention was 25:15 min (min 17:03 min, max 43:00 min). The dose-length product (DLP) of intervention scan was 29.5 mGy · cm (min 6 mGy · cm, max 85 mGy · cm) with the lowest dose for biopsies in the region of the chest (p = 0.04).

Conclusions

With justified indications, CT-guided paediatric interventions are safe, effective and can be performed both, with short intervention times and low radiation exposure.

The Use of Laser Guidance Reduces Fluoroscopy Time for C-Arm Cone-Beam Computed Tomography-Guided Biopsies

PURPOSE

When using laser guidance for cone-beam computed tomography (CBCT)-guided needle interventions, planned needle paths are visualized to the operator without the need to switch between entry- and progress-view during needle placement. The current study assesses the effect of laser guidance during CBCT-guided biopsies on fluoroscopy and procedure times.

MATERIALS AND METHODS

Prospective data from 15 CBCT-guided biopsies of 8-65 mm thoracic and abdominal lesions assisted by a ceiling-mounted laser guidance technique were compared to retrospective data of 36 performed CBCT-guided biopsies of lesions >20 mm using the freehand technique. Fluoroscopy time, procedure time, and number of CBCT-scans were recorded. All data are presented as median (ranges).

RESULTS

For biopsies using the freehand technique, more fluoroscopy time was necessary to guide the needle onto the target, 165 s (83-333 s) compared to 87 s (44-190 s) for laser guidance (p < 0.001). Procedure times were shorter for freehand-guided biopsies, 24 min versus 30 min for laser guidance (p < 0.001).

CONCLUSION

The use of laser guidance during CBCT-guided biopsies significantly reduces fluoroscopy time.

Navigational Tools for Interventional Radiology and Interventional Oncology Applications

The interventional radiologist is increasingly called upon to successfully access challenging biopsy and ablation targets, which may be difficult based on poor visualization, small size, or the proximity of vulnerable regional anatomy. Complex therapeutic procedures, including tumor ablation and transarterial oncologic therapies, can be associated with procedural risk, significant procedure time, and measurable radiation time. Navigation tools, including electromagnetic, optical, laser, and robotic guidance systems, as well as image fusion platforms, have the potential to facilitate these complex interventions with the potential to improve lesion targeting, reduce procedure time, and radiation dose, and thus potentially improve patient outcomes. This review will provide an overview of currently available navigational tools and their application to interventional radiology and oncology. A summary of the pertinent literature on the use of these tools to improve safety and efficacy of interventional procedures compared with conventional techniques will be presented.

Pulmonary ground-glass nodules diagnosis: mean change rate of peak CT number as a discriminative factor of pathology during a follow-up

OBJECTIVE

We aimed to analyse the peak CT number (PEAK) in CT number histogram of ground-glass nodules (GGN), meaning the most frequent density of pixels in the image of pulmonary nodule, based on three-dimensional (3D) reconstructive model pre-operatively, and the mean rate of PEAK change (V-PEAK) during a follow-up of GGN for differential diagnosis between pre-invasive adenocarcinoma (PIA) and invasive adenocarcinoma (IAC).

METHODS

CT number histogram of pixels in GGN was made automatically by 3D measurement software. Diameter, total volume, PEAK and V-PEAK were measured from CT data sets of different groups classified by pathology, subtype and number of GGN, respectively.

RESULTS

Among all 102 cases, 47 were PIA, including atypical adenomatous hyperplasia (n = 29) and adenocarcinoma in situ (n = 18), and 55 were IAC, including minimally IAC (MIA, n = 4). By Wilcoxon test, PEAK of IAC was significantly higher than that of PIA (p < 0.001). By receiver operating curve analysis, area under the curve (AUC) was 0.857 and threshold -820.50 Hounsfield units (HU) for differentiation between PIA and IAC. V-PEAK of IAC was unexpectedly remarkably smaller than that of PIA (p < 0.001) with AUC and threshold being 0.810 and -0.829 HU day(-1), respectively.

CONCLUSION

Pre-operative PEAK and V-PEAK, which interpret and evaluate the change of volume and density of pulmonary nodule simultaneously from both exterior and interior perspectives, can help to distinguish IAC from PIA.

ADVANCES IN KNOWLEDGE

This study provided researchers of GGN another perspective, taking both volume and density of nodules into consideration for pathological evaluation.

The Uro Dyna-CT Enables Three-dimensional Planned Laser-guided Complex Punctures

BACKGROUND

Ultrasound and fluoroscopy are the standard imaging techniques used to perform punctures in urology. Cross-sectional and three-dimensional (3D) imaging may enable safer procedures, especially in complex cases.

OBJECTIVES

To assess the feasibility of 3D planned laser-guided punctures in urology performed with the Uro Dyna-CT (Siemens Healthcare Solutions, Erlangen, Germany).

DESIGN, SETTING, AND PARTICIPANTS

A total of 27 punctures using the laser-guided system syngo iGuide (Artis Zee Ceiling; Siemens Healthcare Solutions, Erlangen, Germany) for the Uro Dyna-CT have been performed to date. Patients with complex puncture indications due to unclear ultrasound findings or a suspicion of surrounding bowel were included.

SURGICAL PROCEDURE

Image acquisition was performed using a customized 8s syngo iGuide protocol of the Uro Dyna-CT. The puncture tract was planned after 3D and cross-sectional image reconstruction. The puncture was performed supported by the laser-guiding system.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary end point of our assessment was accuracy and applicability of the system in a clinical setting. Secondary end points were planning time, puncture time, and radiation exposure of the patient.

RESULTS AND LIMITATIONS

Overall, 24 of 27 punctures were successful. No severe complications occurred. Median radiation dose of the Uro Dyna-CT scan was 6113.1 micrograys meter squared (μGym(2); range: 1081.6-7957.2μGym(2)). The small patient cohort is the major limitation of our study.

CONCLUSIONS

We believe the Uro Dyna-CT-based puncture technique is an excellent additional instrument that allows the urologist to handle complex punctures. Image acquisition leads to higher radiation doses than standard fluoroscopy but does not exceed the radiation exposure of alternative procedures such as computed tomography (CT)-guided punctures with multidetector CT, which is used mainly for complex cases.

PATIENT SUMMARY

We report our experience with a three-dimensional planning and laser-guiding tool to perform complex punctures for urologic indications. The technique is feasible in the endourologic intervention suite.

Intervention Planning Using a Laser Navigation System for CT-Guided Interventions: A Phantom and Patient Study

Objective

To investigate the accuracy, efficiency and radiation dose of a novel laser navigation system (LNS) compared to those of free-handed punctures on computed tomography (CT).

Materials and Methods

Sixty punctures were performed using a phantom body to compare accuracy, timely effort, and radiation dose of the conventional free-handed procedure to those of the LNS-guided method. An additional 20 LNS-guided interventions were performed on another phantom to confirm accuracy. Ten patients subsequently underwent LNS-guided punctures.

Results

The phantom 1-LNS group showed a target point accuracy of 4.0 ± 2.7 mm (freehand, 6.3 ± 3.6 mm; p = 0.008), entrance point accuracy of 0.8 ± 0.6 mm (freehand, 6.1 ± 4.7 mm), needle angulation accuracy of 1.3 ± 0.9° (freehand, 3.4 ± 3.1°; p < 0.001), intervention time of 7.03 ± 5.18 minutes (freehand, 8.38 ± 4.09 minutes; p = 0.006), and 4.2 ± 3.6 CT images (freehand, 7.9 ± 5.1; p < 0.001). These results show significant improvement in 60 punctures compared to freehand. The phantom 2-LNS group showed a target point accuracy of 3.6 ± 2.5 mm, entrance point accuracy of 1.4 ± 2.0 mm, needle angulation accuracy of 1.0 ± 1.2°, intervention time of 1.44 ± 0.22 minutes, and 3.4 ± 1.7 CT images. The LNS group achieved target point accuracy of 5.0 ± 1.2 mm, entrance point accuracy of 2.0 ± 1.5 mm, needle angulation accuracy of 1.5 ± 0.3°, intervention time of 12.08 ± 3.07 minutes, and used 5.7 ± 1.6 CT-images for the first experience with patients.

Conclusion

Laser navigation system improved accuracy, duration of intervention, and radiation dose of CT-guided interventions.

Treatment of supratentorial spontaneous intracerebral hemorrhage using image-guided minimally invasive surgery: Initial experiences of a flat detector CT-based puncture planning and navigation system in the angiographic suite

BACKGROUND AND PURPOSE

The intracerebral hemorrhage drainage through minimally invasive approach is emerging as an alternative for traditional craniotomy, due to its improved survival rate and reduced complication rate. In this study, we investigated the feasibility and safety of a flat detector CT-based puncture planning and navigation system for minimally invasive hematoma drainage on patients with intracerebral hemorrhage.

MATERIALS AND METHODS

The minimally invasive hematoma drainage was performed on 21 hypertensive patients with intracerebral hemorrhage in the angiographic suite with the guidance of a flat detector CT-based puncture planning and navigation system. This system is integrated in the angiographic machine, and was used for 1) planning the needle path based on a preprocedural flat detector CT scan, 2) advancing the catheter with real-time fluoroscopic guidance, and 3) confirming the procedure outcome based on an immediate postprocedural flat detector CT. The surgery efficiency, accuracy, and the treatment outcome were measured and compared with the published data.

RESULTS

All procedures were successfully completed with the catheter placed 4 ± 1 mm from the planned position. The average surgery time was 40 ± 7 minutes. The volume of the hematoma was reduced to 28 ± 4% of the original volume. The Glasgow Coma Scale score was significantly improved from 10 ± 1 at the admission to 14 ± 1 at the discharge. The Extended Glasgow Coma Scale score also improved from 5 ± 1 at the discharge to 6 ± 1 at the 6-month follow-up. No major complication, rebleeding, and mortality were observed in this study.

CONCLUSIONS

This flat detector CT-based needle guidance system provided a feasible, convenient, and safe way to perform the puncture and drainage of brain hematoma in the angiographic suite.

[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.

Tracked ultrasonography snapshots enhance needle guidance for percutaneous renal access: a pilot study

BACKGROUND AND PURPOSE

Although ultrasonography-guided percutaneous nephrostomy is relatively safe, a number of factors make it challenging for inexperienced operators. A computerized needle navigation technique using tracked ultrasonography snapshots was investigated to determine whether performance of percutaneous nephrostomy by inexperienced users could be improved.

METHODS

Ten operators performed the procedure on a phantom model with alternating needle guidance between conventional ultrasonography and tracked ultrasonography snapshots. The needle was reinserted until fluid backflow confirmed calyceal access. Needle trajectories were recorded using the real time needle navigation system for offline evaluation of operator performance. Recorded needle trajectories were used to measure needle motion path length inside the phantom tissue, number of reinsertions, total procedure time, and needle insertion time as end points of this study.

RESULTS

Needle path length measured inside the phantom tissue was significantly lower with ultrasonography snapshots guidance (295.0±23.1 mm, average±standard error of the mean) compared with control procedures (977.9±144.4 mm, P<0.01). This was associated with a significantly lower number of needle insertion attempts with ultrasonography snapshots (average 1.27±0.10 vs 2.83±0.31, P<0.01). The total procedure time and the needle insertion time were also significantly lower with ultrasonography snapshots guidance.

CONCLUSION

Tracked ultrasonography snapshots appear to improve the performance of percutaneous nephrostomy in these preliminary investigations, justifying further validation studies. The presented navigation system is reproducible because of commercially available hardware and open-source software components, facilitating its potential role in clinical practice.

Extracorporeal shock wave lithotripsy: An opinion on its future

The development of miniaturized nephroscopes which allow one-stage stone clearance with minimal morbidity has brought the role of shock wave lithotripsy (SWL) in stone management into question. Design innovations in SWL machines over the last decade have attempted to address this problem. We reviewed the recent literature on SWL using a MEDLINE/PUBMED research. For commenting on the future of SWL, we took the subjective opinion of two senior urologists, one mid-level expert, and an upcoming junior fellow. There have been a number of recent changes in lithotripter design and techniques. This includes the use of multiple focus machines and improved coupling designs. Additional changes involve better localization real-time monitoring. The main goal of stone treatment today seems to be to get rid of the stone in one session rather than being treated multiple times non-invasively. Stone treatment in the future will be individualized by genetic screening of stone formers, using improved SWL devices for small stones only. However, there is still no consensus about the design of the ideal lithotripter. Innovative concepts such as emergency SWL for ureteric stones may be implemented in clinical routine.

Laser-guided cervical selective nerve root block with the Dyna-CT: initial experience of three-dimensional puncture planning with an ex-vivo model

Background

Cervical selective nerve root block (CSNRB) is a well-established, minimally invasive procedure to treat radicular cervical pain. However, the procedure is technically challenging and might lead to major complications. The objective of this study was to evaluate the feasibility of a three-dimensional puncture planning and two-dimensional laser-guidance system for CSNRB in an ex-vivo model.

Methods

Dyna-CT of the cervical spine of an ex-vivo lamb model was performed with the Artis Zee® Ceiling (Siemens Medical Solutions, Erlangen, Germany) to acquire multiplanar reconstruction images. 15 cervical nerve root punctures were planned and conducted with the syngo iGuide® laser-guidance system. Needle tip location and contrast dye distribution were analyzed by two independent investigators. Procedural, planning, and fluoroscopic time, tract length, and dose area product (DAP) were acquired for each puncture.

Results

All 15 punctures were rated as successful with 12 punctures on the first attempt. Total procedural time was approximately 5 minutes. Mean planning time for the puncture was 2.03 (±0.39) min. Mean puncture time was 2.16 (±0.32) min, while mean fluoroscopy time was 0.17 (±0.06) min. Mean tract length was 2.68 (±0.23) cm. Mean total DAP was 397.45 (±15.63) µGy m².

Conclusion

CSNRB performed with Dyna-CT and the tested laser guidance system is feasible. 3D pre-puncture planning is easy and fast and the laser-guiding system ensures very accurate and intuitive puncture control.

[New puncture techniques in urology using 3D-assisted imaging]

The selective use of various puncture techniques for diagnostic or therapeutic purposes is a component of the daily routine of urologists. The aim of these interventions is always a safe and rapid puncture at the appropriate target point. Nowadays, imaging systems are increasingly being used in urology with the aim to achieve a more precise and safer planning and execution of punctures through an increased accuracy by the use of 3D representation. An approach to the solution to achieve this aim is the fusion of 3D reconstruction by magnetic resonance imaging (MRI) or computed tomography< (CT) with real-time imaging procedures, such as sonography or fluoroscopy.

Collecting system percutaneous access using real-time tracking sensors: first pig model in vivo experience

PURPOSE

Precise needle puncture of the renal collecting system is an essential but challenging step for successful percutaneous nephrolithotomy. We evaluated the efficiency of a new real-time electromagnetic tracking system for in vivo kidney puncture.

MATERIALS AND METHODS

Six anesthetized female pigs underwent ureterorenoscopy to place a catheter with an electromagnetic tracking sensor into the desired puncture site and ascertain puncture success. A tracked needle with a similar electromagnetic tracking sensor was subsequently navigated into the sensor in the catheter. Four punctures were performed by each of 2 surgeons in each pig, including 1 each in the kidney, middle ureter, and right and left sides. Outcome measurements were the number of attempts and the time needed to evaluate the virtual trajectory and perform percutaneous puncture.

RESULTS

A total of 24 punctures were easily performed without complication. Surgeons required more time to evaluate the trajectory during ureteral than kidney puncture (median 15 seconds, range 14 to 18 vs 13, range 11 to 16, p=0.1). Median renal and ureteral puncture time was 19 (range 14 to 45) and 51 seconds (range 45 to 67), respectively (p=0.003). Two attempts were needed to achieve a successful ureteral puncture. The technique requires the presence of a renal stone for testing.

CONCLUSIONS

The proposed electromagnetic tracking solution for renal collecting system puncture proved to be highly accurate, simple and quick. This method might represent a paradigm shift in percutaneous kidney access techniques.

Construction of a three-dimensional model of renal stones: comprehensive planning for percutaneous nephrolithotomy and assistance in surgery

OBJECTIVES

To construct a three-dimensional (3D) model of renal stones to facilitate comprehensive planning for percutaneous nephrolithotomy (PCNL) and to assist in surgery.

METHODS

Fifteen patients with complex renal stones, including one patient with a horseshoe kidney, eight patients with partial/complete staghorn, and six patients with multiple renal stones, participated in our study. Computed tomography images of the unenhanced, arterial, venous, and excretory phases were obtained before surgery. Image segmentation and 3D reconstruction of the renal stones were performed using Mimics 12.1 software. A virtual safe and reliable percutaneous renal access route were established for each patient by comprehensive planning based on the 3D model of renal stones. PCNL was subsequently performed with the assistance of the 3D model. Patient demographics, surgical details, and postoperative treatment parameters were recorded.

RESULTS

The 3D models of renal stones accurately represented the interrelationships between the intrarenal arteries and veins, collecting system, stones, and adjacent anatomical structures. PCNL was completed successfully in all 15 patients. The mean operating time was 75.6 ± 13.4 min. The change in hemoglobin concentration was 1.2 ± 0.3 g/l. The one-stage stone-free rate was 93.3%, and the final stone-free rate was 100%. No major postoperative complications were noted, except for postoperative pain in one case.

CONCLUSION

Construction of a 3D model of renal stones with the aim of minimizing the risks of percutaneous procedures and achieving higher one-stage stone-free rates is feasible for comprehensive PCNL planning and assistance in patients with complex renal stones.

Influence of endourological devices on 3D reconstruction image quality using the Uro Dyna-CT

PURPOSE

The urological Dyna-CT (Uro Dyna-CT) was established in clinical use for classical imaging as well as for interventional surgery. To evaluate whether irradiation artefacts may occur during interventional surgery, we analysed the impact of different instruments on 3D reconstruction in the Uro Dyna-CT.

MATERIALS AND METHODS

Ten different endourological instruments [ureterorenoscope (URS)-fibrescope, percutaneous nephrolithotomy (PCNL) working sheath] and accessory equipments such as ureteral catheter, guide wires and stents (DJ, MJ) were introduced in a porcine renal pelvis either retrograde via the ureter or transparenchymally. Subsequently, digital fluoroscopy, standard X-ray and an Uro Dyna-CT were performed. Three colleagues evaluated the image quality independent from each other.

RESULTS

There were basically no limitations regarding image quality in digital fluoroscopy and standard X-ray. In the Uro Dyna-CT, only with the URS fiberscope and the PCNL working sheath, small artefacts and irradiations were detected, whereas ureteric catheter with and without wire, as well as the hydrophilic guide wire, showed no artefacts at all. The remaining material demonstrated minimal artefacts, which did not affect the image quality.

CONCLUSIONS

The Uro Dyna-CT can be used for all interventional endourological procedures using the common armamentarium and instruments without significant limitation of image quality. There are only minor limitations according a PCNL working sheath and the rigid URS. These instruments should be removed out of the examination field before performing the computed tomography and be replaced afterwards by using a safety wire.

Optimizing imaging quality in endourology with the Uro Dyna-CT: contrast agent dilution matters

BACKGROUND AND PURPOSE

The implementation of the Uro Dyna-CT (Siemens Healthcare Solutions, Erlangen, Germany) with interventional 3D- and cross-sectional imaging necessitates the development of new standards for endourologic procedures such as the customized use of diluted contrast agent. Our aim was to find the ideal contrast agent dilution (CAD) for the interventional use of the Uro Dyna-CT in a standardized setting and prove the experimental findings in a clinical case.

MATERIALS AND METHODS

Retrograde pyelographies were performed with 10 different CADs of Imeron 300 (Bracco, Konstanz, Germany) in 10 different pig's urinary tracts. Fluoroscopy, X-ray, 3D- and slice-image reconstruction was performed with the Uro Dyna-CT. Image quality was evaluated, blinded and randomized by 5 observers. Small plastic jars were filled with the CADs and 2 artificial stones (Plaster of paris). Images were evaluated by two observers. The ex vivo findings were transferred to a clinical setting in a complex percutaneous lithotomy procedure. Unweighted and weighted kappa coefficients were calculated to indicate the degree of observers' agreement.

RESULTS

Twenty percent diluted contrast agent provides the best image quality and stone detection when interventional cross-sectional imaging is considered without limitations in fluoroscopy or X-ray quality. This was proved in a percutaneous lithotomy of an obese patient.

CONCLUSIONS

Image quality of the Uro Dyna-CT can be optimized by the use of 20 % diluted contrast agent. This knowledge helps to provide high-quality 3D imaging in the endourological operation room.