Is It the Load That Breaks You or the Way You Carry It: How Demanding Is Endourology?

Objective: Surgical outcomes are dependent on multiple factors. Besides patient-related or procedure-related factors, several surgeon-related factors contribute to surgical outcomes. The Surgery Task Load Index (SURG-TLX) questionnaire helps to assess the impact of several stressors on the perceived demands of surgeons during surgery. In this study, we evaluate the applicability of the SURG-TLX questionnaire for endourologic procedures and set a first point of reference. Materials and Methods: Between March and August 2022, 15 urologists and urology residents at a tertiary referral center for endourology completed the SURG-TLX questionnaire after endourologic procedures. After data acquisition, all participants were asked to evaluate the applicability of the questionnaire for endourologic procedures. Results: A total of 130 procedures were included between March and August 2022. Situational stress had the lowest median score (3.0/20; interquartile range [IQR] 2.0-7.0) and task complexity the highest (5.0/20; IQR 3.0-8.0). After weighing, the dimensions showed different proportions when compared with the nonweighted scores. Distractions received the highest score (15.0/100; IQR 7.5-32.8), temporal demands (6.0/100; IQR 3.0-12.5), and situational stress the lowest (6.0/100; IQR 2.0-21.0). This was caused by the higher weight that was attributed to distractions (3.4/5), as opposed to task complexity (2.6/5). In the questionnaire regarding applicability of the SURG-TLX, the overall satisfaction (6.0/10; IQR 5.0-7.0) and clarity (6.5/10; IQR 5.0-7.5) were moderate. The user-friendliness and applicability of the questionnaire were rated high (7.0/10; IQR 5.5-8.0 and 7.0/10; IQR 6.0-8.0, respectively) and task load (3.0/10; IQR 2.0-5.0) and time load (2.0/10; IQR 2.0-3.5) low. Conclusion: The SURG-TLX questionnaire is appropriate to assess the different dimensions of workload during endourologic procedures. Furthermore, the perceived workload during endourologic procedures is relatively low.

An In-vivo Prospective Study of the Diagnostic Yield and Accuracy of Optical Biopsy Compared with Conventional Renal Mass Biopsy for the Diagnosis of Renal Cell Carcinoma: The Interim Analysis.

BACKGROUND: Lack of accuracy in preoperative imaging leads to overtreatment of benign renal masses (RMs) or indolent renal cell carcinomas (RCCs). Optical coherence tomography (OCT) is real time and high resolution, enabling quantitative analysis through attenuation coefficient (µOCT, mm-1). OBJECTIVE: To determine the accuracy and diagnostic yield of OCT and renal mass biopsy (RMB) for the differentiation of benign RMs versus RCC and oncocytoma versus RCC. DESIGN, SETTING, AND PARTICIPANTS: From October 2013 to June 2016, 95 patients with solid enhancing RMs on cross-sectional imaging were prospectively included. All patients underwent subsequent excision or ablation. INTERVENTION: Percutaneous, image-guided, needle-based OCT followed by RMB in an outpatient setting under local anaesthesia. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Accuracy and diagnostic yield, µOCT correlated to resection pathology or second biopsy during ablation. Tables (2×2) for RMB, receiver operating characteristic curve for OCT. Mann-Whitney test to differentiate µOCT of RMs. RESULTS AND LIMITATIONS: RMB diagnostic yield was 79% with sensitivity, specificity, positive predictive value, and negative predictive value (NPV) of 100%, 89%, 99%, and 100%, respectively. Diagnostic yield and added value of OCT to differentiate RCC from benign was 99% and 15%, respectively. Significant difference was observed in median µOCT between benign RMs (3.2mm-1, interquartile range [IQR]: 2.65-4.35) and RCCs (4.3mm-1, IQR: 3.70-5.00), p=0.0171, and oncocytomas (3.38mm-1, IQR: 2.68-3.95) and RCCs (4.3mm-1, IQR: 3.70-5.00), p=0.0031. OCT showed sensitivity, specificity, positive predictive value. and NPV of 91%, 56%, 91%, and 56%, respectively, to differentiate benign RMs from RCCs and 92%, 67%, 95%, and 55%, respectively, to differentiate oncocytoma from RCC. Limitations include two reference standards and heterogeneity benign RMs. CONCLUSIONS: Compared with RMB, OCT has a higher diagnostic yield. OCT accurately distinguishes benign RMs from RCCs, and oncocytoma from RCCs, although specificity and NPV are lower. PATIENT SUMMARY: Optical coherence tomography, a new optical scan, exhibits similar sensitivity and positive predictive value than renal mass biopsy, although lower specificity and negative predictive value. Optical coherence tomography has a higher diagnostic yield for diagnosing renal cell carcinoma.

Percutaneous Needle Based Optical Coherence Tomography for the Differentiation of Renal Masses: a Pilot Cohort.

PURPOSE: We determine the ability of percutaneous needle based optical coherence tomography to differentiate renal masses by using the attenuation coefficient (µOCT, mm(-1)) as a quantitative measure. MATERIALS AND METHODS: Percutaneous needle based optical coherence tomography of the kidney was performed in patients presenting with a solid renal mass. A pathology specimen was acquired in the form of biopsies and/or a resection specimen. Optical coherence tomography results of 40 patients were correlated to pathology results of the resected specimens in order to derive µOCT values corresponding with oncocytoma and renal cell carcinoma, and with the 3 main subgroups of renal cell carcinoma. The sensitivity and specificity of optical coherence tomography in differentiating between oncocytoma and renal cell carcinoma were assessed through ROC analysis. RESULTS: The median µOCT of oncocytoma (3.38 mm(-1)) was significantly lower (p=0.043) than the median µOCT of renal cell carcinoma (4.37 mm(-1)). ROC analysis showed a µOCT cutoff value of greater than 3.8 mm(-1) to yield a sensitivity, specificity, positive predictive value and negative predictive value of 86%, 75%, 97% and 37%, respectively, to differentiate between oncocytoma and renal cell carcinoma. The area under the ROC curve was 0.81. Median µOCT was significantly lower for oncocytoma vs clear cell renal cell carcinoma (3.38 vs 4.36 mm(-1), p=0.049) and for oncocytoma vs papillary renal cell carcinoma (3.38 vs 4.79 mm(-1), p=0.027). CONCLUSIONS: We demonstrated that the µOCT is significantly higher in renal cell carcinoma vs oncocytoma, with ROC analysis showing promising results for their differentiation. This demonstrates the potential of percutaneous needle based optical coherence tomography to help in the differentiation of renal masses, thus warranting ongoing research.

Thermal Energy during Irreversible Electroporation and the Influence of Different Ablation Parameters.

PURPOSE: Irreversible electroporation (IRE) uses high-voltage electric fields to achieve cell death. Although the mechanism of IRE is mainly designated as nonthermal, development of secondary Joule heating is inevitable. The study purpose was to gain understanding of temperature development and distribution during IRE. MATERIALS AND METHODS: IRE was performed in a transparent polyacrylamide gel resembling soft tissue. Mechanical effects, changes in temperature gradient, and absolute temperature changes were measured with three different optical techniques (high-speed, color Schlieren, and infrared imaging) to investigate the effect on temperature of variations in voltage, pulse length, active tip length (ATL), interelectrode distance, electrode configuration (parallel, convergent, and divergent), and sequential pulsing (pulse delivery interrupted by breaks). The total delivered energy was calculated. RESULTS: A temperature gradient, starting at the tips of both electrodes and expanding toward each other, developed immediately with pulse delivery. Temperatures increased with increasing voltage (by 2.5°C-40.4°C), pulse length (by 5.3°C-9.8°C), ATL (by 5.9°C-17.6°C), and interelectrode distance (by 7.6°C-21.5°C), in accordance with higher energy delivery. Nonparallel electrode placement resulted in heterogeneous temperature distribution with the peak temperature focused in the area with the shortest interelectrode distance. Sequential pulse delivery significantly reduced the temperature increase compared with continuous pulsing (4.3°C vs 11.7°C). CONCLUSIONS: Voltage, pulse length, interelectrode distance, ATL, and electrode configuration each have a strong effect on temperature development and distribution during IRE. Sequential pulsing reduces the extent and volume of thermal distribution and may prove beneficial with respect to procedural safety.

The efficacy and safety of irreversible electroporation for the ablation of renal masses: a prospective, human, in-vivo study protocol.

BACKGROUND: Electroporation is a novel treatment technique utilizing electric pulses, traveling between two or more electrodes, to ablate targeted tissue. The first in human studies have proven the safety of IRE for the ablation of renal masses. However the efficacy of IRE through histopathological examination of an ablated renal tumour has not yet been studied. Before progressing to a long-term IRE follow-up study it is vital to have pathological confirmation of the efficacy of the technique. Furthermore, follow-up after IRE ablation requires a validated imaging modality. The primary objectives of this study are the safety and the efficacy of IRE ablation of renal masses. The secondary objectives are the efficacy of MRI and CEUS in the imaging of ablation result. METHODS/DESIGN: 10 patients, age ≥ 18 years, presenting with a solid enhancing mass, who are candidates for radical nephrectomy will undergo IRE ablation 4 weeks prior to radical nephrectomy. MRI and CEUS imaging will be performed at baseline, one week and four weeks post IRE. After radical nephrectomy, pathological examination will be performed to evaluate IRE ablation success. DISCUSSION: The only way to truly assess short-term (4 weeks) ablation success is by histopathology of a resection specimen. In our opinion this trial will provide essential knowledge on the safety and efficacy of IRE of renal masses, guiding future research of this promising ablative technique. TRIAL REGISTRATION: Clinicaltrials.gov registration number NCT02298608 . Dutch Central Committee on Research Involving Human Subjects registration number NL44785.018.13.

Irreversible electroporation of the porcine kidney: Temperature development and distribution.

OBJECTIVE: Although tissue ablation by irreversible electroporation (IRE) has been characterized as nonthermal, the application of frequent repetitive high-intensity electric pulses has the potential of substantially heating the targeted tissue and causing thermal damage. This study evaluates the risk of possible thermal damage by measuring temperature development and distribution during IRE of porcine kidney tissue. METHODS: The animal procedures were conducted following an approved Institutional Animal Ethics Committee protocol. IRE ablation was performed in 8 porcine kidneys. Of them, 4 kidneys were treated with a 3-needle configuration and the remaining 4 with a 4-needle configuration. All IRE ablations consisted of 70 pulses with a length 90 µs. The pulse frequency was set at 90 pulses/min, and the pulse intensity at 1,500 V/cm with a spacing of 15 mm between the needles. The temperature was measured internally using 4 fiber-optic temperature probes and at the surface using a thermal camera. RESULTS: For the 3-needle configuration, a peak temperature of 57°C (mean = 49 ± 10°C, n = 3) was measured in the core of the ablation zone and 40°C (mean = 36 ± 3°C, n = 3) at 1cm outside of the ablation zone, from a baseline temperature of 33 ± 1°C. For the 4-needle configuration, a peak temperature of 79°C (mean = 62 ± 16°C, n = 3) was measured in the core of the ablation zone and 42°C (mean = 39 ± 3°C, n = 3) at 1cm outside of the ablation zone, from a baseline of 35 ± 1°C. The thermal camera recorded the peak surface temperatures in the center of the ablation zone, reaching 31°C and 35°C for the 3- and 4-needle configuration IRE (baseline 22°C). CONCLUSIONS: The application of repetitive high-intensity electric pulses during IRE ablation in porcine kidney causes a lethal rise in temperature within the ablation zone. Temperature monitoring should be considered when performing IRE ablation near vital structures.

Irreversible electroporation: just another form of thermal therapy?

BACKGROUND: Irreversible electroporation (IRE) is (virtually) always called non-thermal despite many reports showing that significant Joule heating occurs. Our first aim is to validate with mathematical simulations that IRE as currently practiced has a non-negligible thermal response. Our second aim is to present a method that allows simple temperature estimation to aid IRE treatment planning. METHODS: We derived an approximate analytical solution of the bio-heat equation for multiple 2-needle IRE pulses in an electrically conducting medium, with and without a blood vessel, and incorporated published observations that an electric pulse increases the medium's electric conductance. RESULTS: IRE simulation in prostate-resembling tissue shows thermal lesions with 67-92°C temperatures, which match the positions of the coagulative necrotic lesions seen in an experimental study. Simulation of IRE around a blood vessel when blood flow removes the heated blood between pulses confirms clinical observations that the perivascular tissue is thermally injured without affecting vascular patency. CONCLUSIONS: The demonstration that significant Joule heating surrounds current multiple-pulsed IRE practice may contribute to future in-depth discussions on this thermal issue. This is an important subject because it has long been under-exposed in literature. Its awareness pleads for preventing IRE from calling "non-thermal" in future publications, in order to provide IRE-users with the most accurate information possible. The prospect of thermal treatment planning as outlined in this paper likely aids to the important further successful dissemination of IRE in interventional medicine. Prostate 75:332-335, 2015. © 2014 The Authors. The Prostate Published by Wiley Periodicals, Inc.