Unpacking the Broad Landscape of Intraoperative Stressors for Clinical Personnel: A Mixed-Methods Systematic Review.

Purpose: The main goals of this mixed-methods systematic review are to identify what types of intraoperative stressors for operating room personnel have been reported in collected studies and examine the characteristics of each intraoperative stressor. Methods: With a systematic literature search, we retrieved empirical studies examining intraoperative stress published between 2010 and 2020. To synthesize findings, we applied two approaches. First, a textual narrative synthesis was employed to summarize key study information of the selected studies by focusing on surgical platforms and study participants. Second, a thematic synthesis was employed to identify and characterize intraoperative stressors and their subtypes. Results: Ninety-four studies were included in the review. Regarding the surgical platforms, the selected studies mainly focused on minimally invasive surgery and few studies examined issues around robotic surgery. Most studies examined intra-operative stress from surgeons' perspectives but rarely considered other clinical personnel such as nurses and anesthetists. Among seven identified stressors, technical factors were the most frequently examined followed by individual, operating room environmental, interpersonal, temporal, patient, and organizational factors. Conclusion: By presenting stressors as multifaceted elements affecting collaboration and interaction between multidisciplinary team members in the operating room, we discuss the potential interactions between stressors which should be further investigated to build a safe and efficient environment for operating room personnel.

Hyperspectral Imaging in Brain Tumor Surgery-Evidence of Machine Learning-Based Performance.

BACKGROUND: Hyperspectral imaging (HSI) has the potential to enhance surgical tissue detection and diagnostics. Definite utilization of intraoperative HSI guidance demands validated machine learning and public datasets that currently do not exist. Moreover, current imaging conventions are dispersed, and evidence-based paradigms for neurosurgical HSI have not been declared. METHODS: We presented the rationale and a detailed clinical paradigm for establishing microneurosurgical HSI guidance. In addition, a systematic literature review was conducted to summarize the current indications and performance of neurosurgical HSI systems, with an emphasis on machine learning-based methods. RESULTS: The published data comprised a few case series or case reports aiming to classify tissues during glioma operations. For a multitissue classification problem, the highest overall accuracy of 80% was obtained using deep learning. Our HSI system was capable of intraoperative data acquisition and visualization with minimal disturbance to glioma surgery. CONCLUSIONS: In a limited number of publications, neurosurgical HSI has demonstrated unique capabilities in contrast to the established imaging techniques. Multidisciplinary work is required to establish communicable HSI standards and clinical impact. Our HSI paradigm endorses systematic intraoperative HSI data collection, which aims to facilitate the related standards, medical device regulations, and value-based medical imaging systems.

Utilizing Grasp Monitoring to Predict Microsurgical Expertise.

INTRODUCTION: Most microsurgical procedures require the surgeon to use tools to grasp and hold fragile objects in the surgical site. Prior research on grasping in surgery has mostly either been in other surgical techniques or used grasping as an auxiliary metric. We focus on microsurgery and investigate what grasping can tell about microsurgical skill and suturing performance. This study lays groundwork for using automatic detection of grasps to evaluate surgical skill. METHODS: Five expert surgeons and six novices completed sutures on a microsurgical training board. Video recordings of the performance were annotated for the number of grasps, while an eye tracker recorded the participants' pupil dilations for cognitive workload assessment. Performance was measured with suturing duration and the University of Western Ontario Microsurgical Skills Assessment instrument (UWOMSA). Differences in skill, suturing performance and cognitive workload were compared with grasping behavior. RESULTS: Novices needed significantly more grasps to complete sutures and failed to grasp more often than the experts. The number of grasps affected the suturing duration more in novices. Decreasing suturing efficiency as measured by UWOMSA instrument was associated with increase in grasps, even when we controlled for overall skill differences. Novices displayed larger pupil dilations when averaged over a sufficiently large sample, and the difference increased after the grasp. CONCLUSIONS: Grasping action during microsurgical procedures can be used as a conceptually simple yet objective proxy in microsurgical performance assessment. If the grasps could be detected automatically, they could be used to aid in computational evaluation of surgical trainees' performance.

Computer-based Eye-tracking Analysis of King-Devick Test Differentiates Persons With Idiopathic Normal Pressure Hydrocephalus From Cognitively Unimpaired.

BACKGROUND: Functional defects in eye movements and reduced reading speed in neurodegenerative diseases represent a potential new biomarker to support clinical diagnosis. We investigated whether computer-based eye-tracking (ET) analysis of the King-Devick (KD) test differentiates persons with idiopathic normal pressure hydrocephalus (iNPH) from cognitively unimpaired [control (CO)] and persons with Alzheimer's disease (AD). METHODS: We recruited 68 participants (37 CO, 10 iNPH, and 21 AD) who underwent neurological examination, the Consortium to Establish a Registry for Alzheimer's Disease neuropsychological test battery (CERAD-NB), and a Clinical Dementia Rating interview. The KD reading test was performed using computer-based ET. We analyzed the total time used for the reading test, number of errors, durations of fixation and saccade, and saccade amplitudes. RESULTS: The iNPH group significantly differed from the CO group in the KD test mean total time (CO 69.3 s, iNPH 87.3 s; P ≤0.009) and eye-tracking recording of the mean saccade amplitude (CO 3.6 degree, iNPH 3.2 degree; P ≤0.001). The AD group significantly differed from the CO group in each tested parameter. No significant differences were detected between the iNPH and AD groups. CONCLUSION: For the first time, we demonstrated altered reading ability and saccade amplitudes in patients with iNPH.

Detection improvement of gliomas in hyperspectral imaging of protoporphyrin IX fluorescence - in vitro comparison of visual identification and machine thresholds.

BACKGROUND: 5-aminolevulinic acid (5-ALA) - precursor of protoporphyrin IX (PpIX) - is utilized in fluorescence guided surgery (FGS) of high-grade gliomas. PpIX is used to identify traces of glioma during resection. Visual inspection of the fluorescence seems inaccurate in comparison to optic techniques such as hyperspectral imaging (HSI). AIM: To characterize the limits of PpIX fluorescence detection of (i) visual evaluation and (ii) HSI analysis and to (iii) develop a classification system for visible and non-visible PpIX fluorescence. METHODS: Samples with increasing concentrations (C) of PpIX and non-fluorescent controls were evaluated using a surgical microscope under blue light illumination. Similar samples were imaged with a HSI system tuned to PpIX fluorescence peak wavelength (635 nm) and control (RGB) channels. Samples' intensities were defined, leading to 96 analysed pixels after batching. RESULTS: Three expert neurosurgeons assessed the PpIX samples (n = 16) and controls (n = 8) with unanimous decisions (ICC = 0.704), resulting in 63% recognition rate, 48% sensitivity, 92% specificity, 92% positive predictive value (PPV) and 47% negative predictive value (NPV). HSI image analysis, comparing mean relative values, resulted in 96%, 100%, 86%, 94%, 100%, respectively. Minimum PpIX concentration detection for experts was 0.6-1.8 µmol/l and HSI's 0.03-0.15 µmol/l. CONCLUSIONS: PpIX concentrations of low-grade gliomas, and those reported on glioblastoma infiltration zones, are below experts' detection threshold. HSI analysis exceeds the performance of expert's visual inspection nearly by 20-fold. Hybrid FGS-HSI systems should be investigated in parallel to long-term outcomes. Described methods are applicable as a standard for calibration, testing and development of subvisual FGS techniques.

Shortening of Saccades as a Possible Easy-to-Use Biomarker to Detect Risk of Alzheimer's Disease.

BACKGROUND: Wide-ranging functional defects in eye movements have been reported in Alzheimer's disease (AD) dementia. The detection of abnormal eye movements and reading problems may identify persons at risk of AD when clear clinical symptoms are lacking. OBJECTIVE: To examine whether computer-based eye-tracking (ET) analysis of King-Devick (KD) test results differentiates cognitively healthy persons from persons with minor problems in cognitive testing or diagnosed mild AD. METHODS: We recruited 78 participants (57 non-demented, 21 with mild AD) who underwent neurological examination, the Consortium to Establish a Registry for Alzheimer's Disease neuropsychological test battery (CERAD-NB), and a Clinical Dementia Rating (CDR) interview. The non-demented participants were further divided into control (normal CERAD subtests, mean MMSE = 28) and objective mild cognitive impairment (MCI; decline in at least one CERAD memory score, mean MMSE = 27) groups. The KD reading test was performed using computer-based ET. The total time used for the reading test, errors made, fixation and saccade durations, and saccade amplitudes were analyzed. RESULTS: We found significant differences between the control, objective MCI, and AD groups in regard to the mean saccade amplitude (3.58, 3.33, and 3.21 ms, respectively, p < 0.03) and duration (27.1, 25.3, and 24.8 ms, respectively, p < 0.05). The KD error scores in the AD group differed significantly (p < 0.01) from the other groups. CONCLUSION: Computed ET analysis of the KD test may help detect persons with objective MCI early when clear clinical symptoms are lacking. The portable device for ET is easy to use in primary health care memory clinics.

Methods and Measures for Mental Stress Assessment in Surgery: A Systematic Review of 20 Years of Literature.

Real-time mental stress monitoring from surgeons and surgical staff in operating rooms may reduce surgical injuries, improve performance and quality of medical care, and accelerate implementation of stress-management strategies. Motivated by the increase in usage of objective and subjective metrics for cognitive monitoring and by the gap in reviews of experimental design setups and data analytics, a systematic review of 71 studies on mental stress and workload measurement in surgical settings, published in 2001-2020, is presented. Almost 61% of selected papers used both objective and subjective measures, followed by 25% that only administered subjective tools - mostly consisting of validated instruments and customized surveys. An overall increase in the total number of publications on intraoperative stress assessment was observed from mid-2010 s along with a momentum in the use of both subjective and real-time objective measures. Cardiac activity, including heart-rate variability metrics, stress hormones, and eye-tracking metrics were the most frequently and electroencephalography (EEG) was the least frequently used objective measures. Around 40% of selected papers collected at least two objective measures, 41% used wearable devices, 23% performed synchronization and annotation, and 76% conducted baseline or multi-point data acquisition. Furthermore, 93% used a variety of statistical techniques, 14% applied regression models, and only one study released a public, anonymized dataset. This review of data modalities, experimental setups, and analysis techniques for intraoperative stress monitoring highlights the initiatives of surgical data science and motivates research on computational techniques for mental and surgical skills assessment and cognition-guided surgery.

Eye-Tracking Indicators of Workload in Surgery: A Systematic Review.

BackgroundEye tracking is a powerful tool for unobtrusive and real time assessment of workload in clinical settings. Before the complex eye tracking derived surrogates can be proactively utilized to improve surgical safety, the indications, validity and reliability requires careful evaluation.MethodsWe conducted a systematic review of literature from 2010 to 2020 according to PRISMA guidelines. A search on PubMed, Cochrane, Scopus, Web of science, PsycInfo and Google scholar databases was conducted on July 2020. The following search query was used" ("eye tracking" OR "gaze tracking") AND (surgery OR surgical OR operative OR intraoperative) AND (workload OR stress)". Short papers, no peer reviewed or papers in which eye-tracking methodology was not used to investigate workload or stress factors in surgery, were omitted.ResultsA total of 17 (N = 17) studies were identified eligible to this review. Most of the studies (n = 15) measured workload in simulated setting. Task difficulty and expertise were the most studied factors. Studies consistently showed surgeon's eye movements such as pupil responses, gaze patterns, blinks were associated with the level of perceived workload. However, differences between measurements in operational room and simulated environments have been found.ConclusionPupil responses, blink rate and gaze indices are valid indicators of workload. However, the effect of distractions and non-technical factors on workload is underrepresented aspect in the literature even though recognized as underlying factors in successful surgery.

Movement-level process modeling of microsurgical bimanual and unimanual tasks.

PURPOSE: Microsurgical techniques require highly skilled manual handling of specialized surgical instruments. Surgical process models are central for objective evaluation of these skills, enabling data-driven solutions that can improve intraoperative efficiency. METHOD: We built a surgical process model, defined at movement level in terms of elementary surgical actions ([Formula: see text]) and targets ([Formula: see text]). The model also included nonproductive movements, which enabled us to evaluate suturing efficiency and bi-manual dexterity. The elementary activities were used to investigate differences between novice ([Formula: see text]) and expert surgeons ([Formula: see text]) by comparing the cosine similarity of vector representations of a microsurgical suturing training task and its different segments. RESULTS: Based on our model, the experts were significantly more efficient than the novices at using their tools individually and simultaneously. At suture level, the experts were significantly more efficient at using their left hand tool, but the differences were not significant for the right hand tool. At the level of individual suture segments, the experts had on average 21.0 % higher suturing efficiency and 48.2 % higher bi-manual efficiency, and the results varied between segments. Similarity of the manual actions showed that expert and novice surgeons could be distinguished by their movement patterns. CONCLUSIONS: The surgical process model allowed us to identify differences between novices' and experts' movements and to evaluate their uni- and bi-manual tool use efficiency. Analyzing surgical tasks in this manner could be used to evaluate surgical skill and help surgical trainees detect problems in their performance computationally.

Automated tool detection with deep learning for monitoring kinematics and eye-hand coordination in microsurgery.

In microsurgical procedures, surgeons use micro-instruments under high magnifications to handle delicate tissues. These procedures require highly skilled attentional and motor control for planning and implementing eye-hand coordination strategies. Eye-hand coordination in surgery has mostly been studied in open, laparoscopic, and robot-assisted surgeries, as there are no available tools to perform automatic tool detection in microsurgery. We introduce and investigate a method for simultaneous detection and processing of micro-instruments and gaze during microsurgery. We train and evaluate a convolutional neural network for detecting 17 microsurgical tools with a dataset of 7500 frames from 20 videos of simulated and real surgical procedures. Model evaluations result in mean average precision at the 0.5 threshold of 89.5-91.4% for validation and 69.7-73.2% for testing over partially unseen surgical settings, and the average inference time of 39.90 ± 1.2 frames/second. While prior research has mostly evaluated surgical tool detection on homogeneous datasets with limited number of tools, we demonstrate the feasibility of transfer learning, and conclude that detectors that generalize reliably to new settings require data from several different surgical procedures. In a case study, we apply the detector with a microscope eye tracker to investigate tool use and eye-hand coordination during an intracranial vessel dissection task. The results show that tool kinematics differentiate microsurgical actions. The gaze-to-microscissors distances are also smaller during dissection than other actions when the surgeon has more space to maneuver. The presented detection pipeline provides the clinical and research communities with a valuable resource for automatic content extraction and objective skill assessment in various microsurgical environments.

Eye-Hand Coordination of Neurosurgeons: Evidence of Action-Related Fixation in Microsuturing.

OBJECTIVE: We examined performance differences between expert and novice neurosurgeons under a surgical microscope with the goal to evaluate surgical expertise. METHODS: The Tobii eye-tracker was used to record surgeons' eye movements while they performed a microsuturing task. A total of 19 expert and 18 novice trials were recorded under the microscope. Surgical videos were annotated to label subtasks and critical actions. Total suturing time and subtask times were also compared between novice and expert surgeons. At 3 critical and discrete surgical actions (needle piercing into tissue, exiting, and thread cutting) we examined eye fixation that was directly coupled to each of these actions. RESULTS: Compared with novices, expert surgeons completed the suture with shorter total time (258.52 ± 102.14 seconds vs. 330.02 ± 96.52 seconds, P = 0.038), penetration time (17.15 ± 3.50 seconds vs. 26.26 ± 18.58 seconds, P = 0.043), and knot-tying time (194.63 ± 94.55 seconds vs. 262.52 ± 79.05 seconds, P = 0.025). On average, experts displayed longer fixation (1.62 seconds) and preaction fixation time (1.3 seconds) than novices (fixation time = 1.24 seconds, P = 0.048; preaction fixation = 0.82 seconds, P = 0.005)). Experts maintained their visual engagement constantly over the 3 levels of subtasks while novices required a longer fixation time for the challenging piercing action than for the exiting and cutting action. CONCLUSIONS: The action-related fixation can be used to evaluate microsurgeons' level of expertise and in surgical education for gaze training.

Combined Gaze Metrics as Stress-Sensitive Indicators of Microsurgical Proficiency.

Background. Evaluation of microsurgical proficiency is conventionally subjective, time consuming, and unreliable. Eye movement-based metrics have been promising not only in detection of surgical expertise but also in identifying actual cognitive stress and workload. We investigated if pupil dilations and blinks could be utilized in parallel to accurately classify microsurgical proficiency and its moderating features, especially task-related stress. Methods. Participants (n = 11) were divided into groups based on prior experience in microsurgery: novices (n = 6) with no experience and trained microsurgeons (n = 5). All participants conducted standardized suturing tasks with authentic instruments and a surgical microscope. A support vector machine classifier was used to classify features of microsurgical expertise based on percentage changes in pupil size. Results. A total of 109 successful sutures with 1090 segments were recorded. Classification of expertise from sutures achieved accuracies between 74.3% and 76.0%. Classification from individual segments based on these same features was not feasible. Conclusions. Combined gaze metrics are applicable for classifying surgical proficiency during a defined task. Pupil dilation is also sensitive to external stress factors; however, the usefulness of blinks is impaired by low blink rates. The results can be translated to surgical education to improve feedback and should be investigated individually in the context of actual performance and in real patient operations. Combined gaze metrics may be ultimately utilized to help microsurgeons monitor their performance and workload in real time-which may lead to prevention of errors.

Spectrally Tunable Neural Network-Assisted Segmentation of Microneurosurgical Anatomy.

BACKGROUND: Distinct tissue types are differentiated based on the surgeon's knowledge and subjective visible information, typically assisted with white-light intraoperative imaging systems. Narrow-band imaging (NBI) assists in tissue identification and enables automated classifiers, but many anatomical details moderate computational predictions and cause bias. In particular, tissues' light-source-dependent optical characteristics, anatomical location, and potentially hazardous microstructural changes such as peeling have been overlooked in previous literature. METHODS: Narrow-band images of five (n = 5) facial nerves (FNs) and internal carotid arteries (ICAs) were captured from freshly frozen temporal bones. The FNs were split into intracranial and intratemporal samples, and ICAs' adventitia was peeled from the distal end. Three-dimensional (3D) spectral data were captured by a custom-built liquid crystal tunable filter (LCTF) spectral imaging (SI) system. We investigated the normal variance between the samples and utilized descriptive and machine learning analysis on the image stack hypercubes. RESULTS: Reflectance between intact and peeled arteries in lower-wavelength domains between 400 and 576 nm was significantly different (p < 0.05). Proximal FN could be differentiated from distal FN in a higher range, 490-720 nm (p < 0.001). ICA with intact tunica differed from proximal FN nearly thorough the VIS range, 412-592 nm (p < 0.001) and 664-720 nm (p < 0.05) as did its distal counterpart, 422-720 nm (p < 0.001). The availed U-Net algorithm classified 90.93% of the pixels correctly in comparison to tissue margins delineated by a specialist. CONCLUSION: Selective NBI represents a promising method for assisting tissue identification and computational segmentation of surgical microanatomy. Further multidisciplinary research is required for its clinical applications and intraoperative integration.

Optimal eye movement strategies: a comparison of neurosurgeons gaze patterns when using a surgical microscope.

BACKGROUND: Previous studies have consistently demonstrated gaze behaviour differences related to expertise during various surgical procedures. In micro-neurosurgery, however, there is a lack of evidence of empirically demonstrated individual differences associated with visual attention. It is unknown exactly how neurosurgeons see a stereoscopic magnified view in the context of micro-neurosurgery and what this implies for medical training. METHOD: We report on an investigation of the eye movement patterns in micro-neurosurgery using a state-of-the-art eye tracker. We studied the eye movements of nine neurosurgeons while performing cutting and suturing tasks under a surgical microscope. Eye-movement characteristics, such as fixation (focus level) and saccade (visual search pattern), were analysed. RESULTS: The results show a strong relationship between the level of microsurgical skill and the gaze pattern, whereas more expertise is associated with greater eye control, stability, and focusing in eye behaviour. For example, in the cutting task, well-trained surgeons increased their fixation durations on the operating field twice as much as the novices (expert, 848 ms; novice, 402 ms). CONCLUSIONS: Maintaining steady visual attention on the target (fixation), as well as being able to quickly make eye jumps from one target to another (saccades) are two important elements for the success of neurosurgery. The captured gaze patterns can be used to improve medical education, as part of an assessment system or in a gaze-training application.

The Role of Extrafoveal Vision in Source Code Comprehension.

Understanding software engineers' behaviour plays a vital role in the software development industry. It also provides helpful guidelines for teaching and learning. In this article, we conduct a study of the extrafoveal vision and its role in information processing. This is a new perspective on source code comprehension. Despite its major importance, the extrafoveal vision has been largely ignored by previous studies. The available research has been focused entirely on the foveal information processing and the gaze fixation position. In this work, we share the results of a gaze-contingent study of source code comprehension by expert ( N = 12) and novice ( N = 12) programmers in conditions of the restricted extrafoveal vision. The window-moving paradigm was employed to restrict the extrafoveal area of vision as participants comprehend two source code examples. The results indicate that the semantic preview allowed by the extrafoveal vision provides tangible benefits to expert programmers. When the experts could not use the semantic information from the extrafoveal area, their fixation duration increased to duration similar to novices. The experts' performance dropped in the restricted-view mode, and they required more time to solve the tasks.

ScreenMasker: An Open-source Gaze-contingent Screen Masking Environment.

The moving-window paradigm, based on gazecontingent technic, traditionally used in a studies of the visual perceptual span. There is a strong demand for new environments that could be employed by non-technical researchers. We have developed an easy-to-use tool with a graphical user interface (GUI) allowing both execution and control of visual gaze-contingency studies. This work describes ScreenMasker, an environment that allows create gaze-contingent textured displays used together with stimuli presentation software. ScreenMasker has an architecture that meets the requirements of low-latency real-time eye-movement experiments. It also provides a variety of settings and functions. Effective rendering times and performance are ensured by means of GPU processing under CUDA technology. Performance tests show ScreenMasker's latency to be 67-74 ms on a typical office computer, and high-end 144-Hz screen latencies of about 25-28 ms. ScreenMasker is an open-source system distributed under the GNU Lesser General Public License and is available at https://github.com/PaulOrlov/ScreenMasker .

Analysis of disruptive events and precarious situations caused by interaction with neurosurgical microscope.

BACKGROUND: Developments in micro-neurosurgical microscopes have improved operating precision and ensured the quality of outcomes. Using the stereoscopic magnified view, however, necessitates frequent manual adjustments to the microscope during an operation. METHOD: This article reports on an investigation of the interaction details concerning a state-of-the-art micro-neurosurgical microscope. The video data from detailed observations of neurosurgeons' interaction patterns with the microscope were analysed to examine disruptive events caused by adjusting the microscope. RESULTS: The primary findings show that interruptions caused by adjusting the microscope handgrips and mouth switch prolong the surgery time up to 10%. Surgeons, we observed, avoid interaction with the microscope's controls, settings, and configurations by working at the edge of the view, operating on a non-focused view, and assuming unergonomic body postures. CONCLUSIONS: The lack of an automatic method for adjusting the microscope is a major problem that causes interruptions during micro-neurosurgery. From this understanding of disruptive events, we discuss the opportunities and limitations of interactive technologies that aim to reduce the frequency or shorten the duration of interruptions caused by microscope adjustment.

Validating the Restricted Focus Viewer: a study using eye-movement tracking.

Investigation of cognitive processes and visual attention during problem-solving tasks is an important part of understanding human reasoning. Eyetracking technology has proven to have many benefits in revealing visual attention patterns. However, the high price of accurate eyetrackers and the difficulties associated with using them represent major obstacles to their wider application. Therefore, previous studies have sought to find alternatives to eyetracking. The Restricted Focus Viewer (RFV) brings a small part of an otherwise blurred display to the focus of visual attention: A user controls what part of the screen is in focus by using a computer mouse and explicitly selecting the area to be shown in focus. Recently, some studies have employed the RFV to investigate cognitive behavior of users, and some researchers have even enhanced the tool to study usability. We replicated a previous RFV-based study while also recording gaze data. We compared the attention allocation in time and space as reported by the RFV and an eyetracker. Further, we investigated the effects of RFV's display blurring on the visual attention allocation of 18 novice and expert programmers. Our results indicate that the data obtained from the two tools differ. Also, the RFV-blurring interferes with the strategies utilized by experts, and has an effect on fixation duration. However, task performance was preserved.