Development and Validation of a Mixed-Reality Simulator for Reducing Biopsy Core Deviation During Simulated Freehand Systematic Prostate Biopsy.

INTRODUCTION: We describe the development and validation of a mixed-reality prostate biopsy (PBx) simulator with built-in guidance aids and real-time 3-dimensional visualization. METHODS: We evaluated our simulator during one-on-one training sessions with urology residents and attendings from 2018 to 2022. Participants performed freehand, side-fire, double-sextant transrectal ultrasound-guided systematic prostate biopsy (sPBx). After a baseline assessment (first set of 12 biopsy cores), participants trained for 25 minutes with visualization and cognitive aids activated. Training was followed by an exit set of 12 biopsy cores without visualization or cognitive aids and afterward, subjective assessment by trainees of the simulator. Deviation is the shortest distance of the center of a core from its intended template location. RESULTS: Baseline deviations (mean ± SD) for residents (n = 24) and attendings (n = 4) were 13.4 ± 8.9 mm and 8.5 ± 3.6 mm ( P < 0.001), respectively. Posttraining deviations were 8.7 ± 6.6 mm and 7.6 ± 3.7 mm ( P = 0.271), respectively. Deviations between baseline and exit were decreased significantly for residents ( P < 0.001) but not for attendings ( P = 0.093). Overall feedback from participants was positive. Confidence in performing a PBx increased in novices after training ( P = 0.011) and did not change among attendings ( P = 0.180). CONCLUSIONS: A new PBx simulator can quantify and improve accuracy during simulated freehand sPBx while providing visualization and graphical feedback. Improved simulated sPBx accuracy could lead to more even distribution of biopsy cores within the prostate when performed in clinical settings, possibly reducing the high risk of missing an existing lesion and thus decreasing the time to initiating treatment, if indicated.

Simulation Use in Outreach Setting: A Novel Approach to Building Sustainability.

SUMMARY STATEMENT: Simulation is a well-studied teaching tool for multidisciplinary teamwork, crisis resource management, and communication skills. These attributes are essential for successful international medical missions, which include healthcare providers with different familiarities with the outreach environment and each team member's role. However, immersive simulation remains underused in similar settings. Our team designed a simulation-based curriculum that focuses on multidisciplinary teamwork and crisis resource management skills. In this commentary, we describe its implementation during high-risk cleft care outreach missions conducted by the Global Smile Foundation. We discuss the importance of a simple, feasible, and flexible platform to successfully overcome the limitations of time and resources inherent to outreach mission work while addressing the clinical and geographic needs specific to each site. We highlight challenges, including unpredictability of the outreach environment, a language barrier, and the short duration of missions. Finally, we offer a roadmap for groups involved in similar global health efforts.

Manual Conservation of Supplemental Oxygen in Low-Resource Settings During the COVID-19 Pandemic.

SUMMARY STATEMENT: Using a simulated adult COVID-19 patient with hypoxemia, we investigated whether caregivers interrupting oxygen flow by manually occluding oxygen tubing with pliers during exhalation can conserve oxygen while maintaining oxygenation. Oxygen pinching reduced oxygen use by 51% to 64%, maintained simulated oxygen saturation between 88% and 90%, and increased simulated average alveolar partial pressure of oxygen from a room air baseline of approximately 131 to 294-424 mm Hg compared with 607 mm Hg with 10 liters per minute (LPM) continuous oxygen flow. Simulation provided a methodology to rapidly evaluate a technique that has begun to be used with COVID-19 patients in low-resource environments experiencing an acute oxygen shortage.

Attitude is everything: keep probe pitch neutral during side-fire prostate biopsy. A simulator study.

OBJECTIVES: To develop and validate on a simulator a learnable technique to decrease deviation of biopsied cores from the template schema during freehand, side-fire systematic prostate biopsy (sPBx) with the goal of reducing prostate biopsy (PBx) false-negatives, thereby facilitating earlier sampling, diagnosis and treatment of clinically significant prostate cancer. PARTICIPANTS AND METHODS: Using a PBx simulator with real-time three-dimensional visualization, we devised a freehand, pitch-neutral (0°, horizontal plane), side-fire, transrectal ultrasonography (TRUS)-guided sPBx technique in the left lateral decubitus position. Thirty-four trainees on four Canadian and US urology programmes learned the technique on the same simulator, which recorded deviation from the intended template location in a double-sextant template as well as the TRUS probe pitch at the time of sampling. We defined deviation as the shortest distance in millimeters between a core centre and its intended template location, template deviation as the mean of all deviations in a template, and mastery as achieving a template deviation ≤5.0 mm. RESULTS: All results are reported as mean ± sd. The mean absolute pitch and template deviation before learning the technique (baseline) were 8.2 ± 4.1° and 8.0 ± 2.7 mm, respectively, and after mastering the technique decreased to 4.5 ± 2.7° (P = 0.001) and 4.5 ± 0.6 mm (P < 0.001). Template deviation was related to mean absolute pitch (P < 0.001) and increased by 0.5 mm on average with each 1° increase in mean absolute pitch. Participants achieved mastery after practising 3.9 ± 2.9 double-sextant sets. There was no difference in time to perform a double-sextant set at baseline (277 ± 102 s) and mastery (283 ± 101 s; P = 0.39). CONCLUSION: A pitch-neutral side-fire technique reduced template deviation during simulated freehand TRUS-guided sPBx, suggesting it may also reduce PBx false-negatives in patients in a future clinical trial. This pitch-neutral technique can be taught and learned; the University of Florida has been teaching it to all Urology residents for the last 2 years.

Does the Technique for Assessing Loss of Resistance Alter the Magnitude of Epidural Needle Tip Overshoot?

INTRODUCTION: Postdural puncture headache due to accidental dural puncture is a consequence of excessive needle tip overshoot distance after entering the epidural space via a loss of resistance (LOR) technique. We are not aware of any quantitative comparison of the magnitude of needle tip overshoot (distance traveled by the needle tip beyond the point where LOR can be discerned) for the various LOR assessment techniques that are taught. Such a comparison may provide insight into contributing factors of accidental dural puncture and associated postdural puncture headache. METHODS: A custom-built simulator was used to evaluate the following 3 LOR assessment techniques: incremental needle advancement, intermittent LOR assessment (II); continuous needle advancement, high-frequency intermittent LOR assessment (CI); and continuous needle advancement, continuous LOR assessment (CC). RESULTS: There were significant mean differences in maximum overshoot past a virtual LOR plane due to technique (F(2,124) = 79.31, P < 0.001) (Fig. 2). Specifically, maximum overshoot was greater with technique II [mean = 3.8 mm, 95% confidence interval (CI) = 3.4-4.3] versus either CC (mean = 1.9 mm, 95% CI = 1.5-1.8, P < 0.001) or CI (mean = 1.4 mm, 95% CI = 0.9-2.3, P < 0.001). Differences in maximum overshoot between CC and CI were not statistically different (P = 0.996). Maximum overshoot was greater at 4 cm (mean = 3.0 mm, 95% CI = 2.6-3.4) compared with 5 cm (mean = 2.3 mm, 95% CI = 2.0-2.5, P = 0.044), 6 cm (mean = 2.0 mm, 95% CI = 1.9-2.2, P = 0.054), 7 cm (mean = 1.9 mm, 95% CI = 1.7-2.1, P = 0.002), and 8 cm (mean = 1.8 mm, 95% CI = 1.6-2.1, P = 0.001). In addition, maximum overshoot at 5 cm was greater than that at 7 cm (P = 0.020) and 8 cm (P = 0.037). The other LOR depths were not statistically significantly different from each other. Depth did not have a significant interaction with technique (P = 0.517). Technique preference had neither a significant relationship to maximum overshoot (P = 0.588) nor a significant interaction with LOR assessment technique (P = 0.689). DISCUSSION: Technique II LOR assessment produced the greatest needle overshoot past the simulated LOR plane after obtaining LOR. This was consistent across all LOR depths. In this bench study, the II technique resulted in the deepest needle tip maximum overshoot. We are in the process of designing a clinical study to collect similar data in patients.

Hemodynamic Influence on Smooth Muscle Cell Kinetics and Phenotype During Early Vein Graft Adaptation.

Pathologic vascular adaptation following local injury is the primary driver for accelerated intimal hyperplasia and an occlusive phenotype. Smooth muscle cell (SMC) proliferation within the wall, and migration into the developing intima, is a major component of this remodeling response. The primary objective in the current study was to investigate the effect of the local biomechanical forces on early vein graft adaptation, specifically focusing on the spatial and temporal response of SMC proliferation and conversion from a contractile to synthetic architecture. Taking advantage of the differential adaptation that occurs during exposure to divergent flow environments, vein grafts were implanted in rabbits to create two distinct flow environments and harvested at times ranging from 2 h to 28 days. Using an algorithm for the virtual reconstruction of unfixed, histologic specimens, immunohistochemical tracking of DNA synthesis, and high-throughput transcriptional analysis, the spatial and temporal changes in graft morphology, cell proliferation, and SMC phenotype were catalogued. Notable findings include a burst of cell proliferation at 7 days post-implantation, which was significantly augmented by exposure to a reduced flow environment. Compared to the adjacent media, proliferation rates were 3-fold greater in the intima, and a specific spatial distribution of these proliferating cells was identified, with a major peak in the sub-endothelial region and a second peak centering on the internal elastic lamina. Genomic markers of a contractile SMC phenotype were reduced as early as 2 h post-implantation and reached a nadir at 7 days. Network analysis of upstream regulatory pathways identified GATA6 and KLF5 as important transcription factors that regulate this shift in SMC phenotype.