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Surgical navigation systems have demonstrated improvements in alignment accuracy in a number of arthroplasty procedures, but they have not yet been widely adopted for use in total shoulder arthroplasty (TSA). We believe this is due in part to the obtrusiveness of conventional optical tracking systems, as well as the need for additional intraoperative steps such as calibration and registration. The purpose of this study is to evaluate the feasibility of adapting a less-intrusive dental navigation system for use in TSA. We developed a proof-of-concept system based on validated laser-engraved surgical tools recently introduced for use in dental surgery that are calibrated once when manufactured and not recalibrated at time of use. The design also features a notably smaller bone-mounted tracker that can be tracked from a wide range of viewing angles. To assess our system’s performance, we modified the dental surgical software to support guidance of a TSA procedure. We then conducted a user study in which three participants with varying surgical experience used the system to drill 30 holes in a glenoid model. Using a coordinate measuring machine, we determined the resulting drilled trajectory and compared this to the pre-planned trajectory. Since we used a model glenoid rather than anatomical specimens, we report on targeting precision rather than overall procedure precision or accuracy. We found targeting precision

Military personnel deployed to war zones or assigned to other morally challenging military duties are likely to be exposed to potentially morally injurious events (PMIE) that may inflict a moral injury (MI). This qualitative study formed ‘Phase 1’ of a larger study into PMIEs experienced by Australian veterans and the potential pastoral/spiritual care role of chaplains. Two seminars were conducted that involved 10 veterans being interviewed and audio recorded about their deployment experiences to evaluate whether there was any evidence among Australian veterans of a PMIE. Narrative data analysis indicated that all participants had been exposed to, or were involved in, a PMIE of one kind or another. Seven key themes were identified from the analyzed qualitative data: (i) immoral acts, (ii) death and injury, (iii) betrayal, (iv) ethical dilemmas, (v) disproportionate violence, (vi) retribution and (vii) religious/spiritual issues. Given this preliminary PMIE evidence identified, there is a need for further research, as well as the development of a suitable moral injury assessment scale appropriate for Australian veterans. Furthermore, given the ethical, moral, and spiritual issues involved, the implementation of a rehabilitation program suitable for Australian veterans which can be provided by chaplains is also suggested—namely ‘Pastoral Narrative Disclosure.’ It is argued that moral injury needs to be recognized, not just as an issue affecting individual personnel and their families, but is also a community health, organizational and government responsibility.

Complex orthopaedic procedures, such as iliosacral screw (ISS) fixations, can take advantage of surgical navigation technology to achieve accurate results. Although the impact of surgical navigation on outcomes has been studied, no studies to date have quantified how the design of the targeting display used for navigation affects ISS targeting performance. However, it is known in other contexts that how task information is displayed can have significant effects on both accuracy and time required to perform motor tasks, and that this can be different among users with different experience levels. This study aimed to investigate which visualization techniques helped experienced surgeons and inexperienced users most efficiently and accurately align a surgical tool to a target axis. We recruited 21 participants and conducted a user study to investigate five proposed 2D visualizations (bullseye, rotated bullseye, target-fixed, tool-fixed in translation, and tool-fixed in translation and rotation) with varying representations of the ISS targets and tool, and one 3D visualization. We measured the targeting accuracy achieved by each participant, as well as the time required to perform the task using each of the visualizations. We found that all 2D visualizations had equivalent translational and rotational errors, with mean translational errors below 0.9 mm and rotational errors below 1.1 $$^\circ$$ . The 3D visualization had statistically greater mean translational and rotational errors (4.29 mm and 5.47 $$^\circ$$ , p

We designed an Artificial X-ray Imaging System (AXIS) that generates simulated fluoroscopic X-ray images on the fly and assessed its utility in improving C-arm positioning performance by C-arm users with little or no C-arm experience. The AXIS system was comprised of an optical tracking system to monitor C-arm movement, a manikin, a reference CT volume registered to the manikin, and a Digitally Reconstructed Radiograph algorithm to generate live simulated fluoroscopic images. A user study was conducted with 30 participants who had little or no C-arm experience. Each participant carried out four tasks using a real C-arm: an introduction session, an AXIS-guided set of pelvic imaging tasks, a non-AXIS guided set of pelvic imaging tasks, and a questionnaire. For each imaging task, the participant replicated a set of three target X-ray images by taking real radiographs of a manikin with a C-arm. The number of X-rays required, task time, and C-arm positioning accuracy were recorded. We found a significant 53% decrease in the number of X-rays used and a moderate 10–26% improvement in lateral C-arm axis positioning accuracy without requiring more time to complete the tasks when the participants were guided by artificial X-rays. The questionnaires showed that the participants felt significantly more confident in their C-arm positioning ability when they were guided by AXIS. They rated the usefulness of AXIS as very good to excellent, and the realism and accuracy of AXIS as good to very good. Novice users working with a C-arm machine supplemented with the ability to generate simulated X-ray images could successfully accomplish positioning tasks in a simulated surgical setting using markedly fewer X-ray images than when unassisted. In future work, we plan to determine whether such a system can produce similar results in the live operating room without lengthening surgical procedures.

Robotic, navigated, and patient-specific instrumentation (PSI) TKA procedures have been introduced to improve component placement precision and improve implant survivorship and other clinical outcomes. However, the best available evidence has shown that these technologies are ineffective in reducing revision rates in the general TKA patient population. Nonetheless, it seems plausible that these technologies could be an effective and cost-effective means of reducing revision risk in clinical populations that are at an elevated risk of revision because of patient-specific demographics (such as older age at index surgery, elevated BMI, and being a man). Since clinical trials on this topic would need to be very large, a simulation approach could provide insight on which clinical populations would be the most promising for analysis.We conducted a simulation-based analysis and asked: (1) Given key demographic parameters characterizing a patient population, together with estimates of the precision achievable with selected forms of technology assistance in TKA, can we estimate the expected distributions of anticipated reductions in lifetime revision risk for that population and the associated improvements in quality-adjusted life years (QALYs) that would be expected to result? (2) Are there realistic practice characteristics (such as combinations of local patient demographics and capital and per-procedure costs) for which applying a per-patient risk-prioritized policy for using technology-assisted TKA could be considered cost-effective based on projected cost savings from reductions in revision rates?We designed simulations of hypothetical practice-specific clinical scenarios, each characterized by patient volume, patient demographics, and technology-assisted surgical technique, using demographic information drawn from other studies to characterize two contrasting simulated clinical scenarios in which the distributions of factors describing patients undergoing TKA place one population at a comparatively elevated risk of revision (elevated-risk population) and the second at a comparatively reduced risk of revision (lower-risk population). We used results from previous systematic reviews and meta-analyses to estimate the implant precision in coronal plane alignment for patient-specific instrumentation, navigated, and robotic technology. We generated simulated TKA patient populations based on risk estimates from large clinical studies, structured reviews, and meta-analyses and calculated the patient-specific reduction in the revision risk and the change in QALYs attributable to the technology-assisted intervention in each of the two simulated clinical scenarios. We also incorporated a sensitivity analysis, incorporating variations in the effect size of deviations from overall coronal alignment on revision risk and difference in health state utilities acquired through a structured review process. We then simulated the outcomes of 25,000 operations per patient using the precisions associated with the conventional TKA technique, the three technology-assisted techniques, and a hypothetical technology-assisted intervention that could consistently deliver perfectly neutral overall coronal alignment, which is unachievable in practice. A risk-prioritized treatment policy was emulated by ordering the simulated patients from the highest to lowest predicted increase in QALYs, such that simulated patients who would see the greatest increase in the QALYs (and therefore the greatest reduction in lifetime revision risk) were the patients to receive technology-assisted TKA intervention in a practice. We used cost estimates acquired through a structured review process and calculated the net added costs of each of the three technology-assisted techniques as a function of the percent utilization (proportion of patients treated with technology assistance in a practice), factoring in fixed costs, per-procedure variable costs, and savings occurring from the prevention of future revision surgery. Finally, we calculated the incremental cost-effectiveness ratio (ICER) and marginal cost-effectiveness ratio (MCER) for each technology-assisted technique for the two clinical scenarios. We then used a Monte Carlo approach to simulate variations in key patient risk, health state, and economic factors as well as to obtain a distribution of estimates for cost-effectiveness. We considered an intervention to be cost effective if either the ICER or MCER values were below USD/QALY 63,000.For the lower-risk population, the median reduction in the revision risk was 0.9% (0.4% to 2.2%, extrema from the sensitivity analysis) and 1.8% (0.9% to 4.4%) for PSI and robotic TKA, respectively, and 1.9% (1.0% to 4.6%) for ideal TKA. In contrast, the median reduction in the revision risk in the elevated-risk clinical scenario was 2.0% (1.2% to 3.4%) and 4.6% (2.7% to 8.5%) for PSI and robotic TKA and 5.1% (3.0% to 9.4%) for ideal TKA. Estimated differences in the cumulative gain in QALYs attributable to technology-assisted TKA ranged from 0.6 (0.2 to 1.8) to 4.0 (1.8 to 10.0) QALYs per 100 patients, depending on the intervention type and clinical scenario. For PSI, we found treating 15% of patients in the lower-risk population and 77% in the elevated-risk population could meet the threshold for being considered cost effective. For navigated TKA systems offering high alignment precision, we found the intervention could meet this threshold for practice sizes of at least 300 patients per year and a percent utilization of 27% in the lower-risk population. In the elevated-risk population, cost-effectiveness could be achieved in practice volumes as small as 100 patients per year with a percent utilization of at least 6%, and cost savings could be achieved with a percent utilization of at least 45%. We found that robotic TKA could only meet the threshold for being considered cost-effectiveness in the lower-risk population if yearly patient volumes exceeded 600 and for a limited range of percent utilization (27% to 32%). However, in the elevated-risk patient population, robotic TKA with high alignment precision could potentially be cost effective for practice sizes as small as 100 patients per year and a percent utilization of at least 20% if a risk-prioritized treatment protocol were used.Based on these simulations, a selective-use policy for technology-assisted TKA that prioritizes using technology assistance for those patients at a higher risk of revision based on patient-specific factors could potentially meet the cost-effectiveness threshold in selected circumstances (for example, primarily in elevated-risk populations and larger practice sizes). Whether it does meet that threshold would depend significantly on the surgical precision that can be achieved in practice for a given proposed technology as well as on the true local costs of using the proposed technology. We further recommend that any future randomized trials seeking to demonstrate possible effects of technology assistance on revision risk focus on clinical populations that are at higher risk of revision (such as, patient populations that are relatively younger, have higher BMIs, and higher proportions of men).This study suggests that technology assistance is only likely to prove cost effective in selected circumstances rather than in all clinical populations and practice settings. In general, we project that surgical navigation is most likely to prove cost effective in the widest range of circumstances, that PSI may be cost effective or cost neutral in a moderate range of circumstances, and that robotic surgery is only likely to be cost effective in moderately large practices containing patients who are on average at an intrinsically elevated risk of revision.

C-arms are portable X-ray devices used to generate radiographic images in orthopedic surgical procedures. Evidence suggests that scouting images, which are used to aid in C-arm positioning, result in increased operation time and excess radiation exposure. C-arms are also primarily used qualitatively to view images, with limited quantitative functionality. Various techniques have been proposed to improve positioning, reduce radiation exposure, and provide quantitative measuring tools, all of which require accurate C-arm position tracking. While external stereo camera systems can be used for this purpose, they are typically considered too obtrusive. This paper therefore presents the development and verification of a low-profile, real-time C-arm base-tracking system using computer vision techniques. The proposed tracking system, called OPTIX (On-board Position Tracking for Intraoperative X-rays), uses a single downward-facing camera mounted to the base of a C-arm. Relative motion tracking and absolute position recovery algorithms were implemented to track motion using the visual texture in operating room floors. The accuracy of the system was evaluated in a simulated operating room mounted on a real C-arm. The relative tracking algorithm measured relative translation position changes with errors of less than 0.75% of the total distance travelled, and orientation with errors below 5% of the cumulative rotation. With an error-correction step incorporated, OPTIX achieved C-arm repositioning with translation errors of less than $$ 1.10 \pm 0.07 $$ mm and rotation errors of less than $$ 0.17 \pm 0.02^\circ $$ . A display based on the OPTIX measurements enabled consistent C-arm repositioning within 5 mm of a previously stored reference position. The system achieved clinically relevant accuracies and could result in a reduced need for scout images when re-acquiring a previous position. We believe that, if implemented in an operating room, OPTIX has the potential to reduce both operating time and harmful radiation exposure to patients and surgical staff.

Introduction Anastomotic false aneurysms are a late complication of aortic grafting. Treatment usually consists of debridement of the degenerated tissue and placement of a short interposition graft. In infectious situations, graft excision is required. Patient History 80-year-old frail male with numerous comorbidities presented to clinic with an anastomotic pseudoaneurysm (PSA) between the left limb of an aortobifemoral Dacron graft and the common femoral artery. Technical Details The superficial femoral artery (SFA) and deep femoral artery (PFA) were exposed and controlled from an anterior thigh approach. Sheaths were inserted in each artery. An Amplatzer II vascular plug (Abbott, Abbott Park, IL) was deployed in the PFA. A Viabahn (Gore, Flagstaff, AZ) was first deployed in the left limb of the Dacron graft and into the proximal SFA. A Viabahn VBX stent (Gore, Flagstaff, AZ) was then deployed from inside the Viabahn and going proximally further into the limb of the bifurcated Dacron graft. The proximal end of the Viabahn VBX was flared with a larger balloon. The arteriotomies in the SFA and PFA were then used to create a side-to-side anastomosis. There were no immediate complications. On six months follow up, the PSA sac was noted to have decreased in size, and the stents to be patent with no endoleak. Discussion Elective surgical repair of anastomotic PSAs is preferred since emergent repair has significantly higher morbidity and mortality. Still, open elective repair has its own mortality and limb loss risks in addition to postoperative wound infection, seroma, hematoma, recurrence, along with myocardial infarction and stroke. The novel procedure we performed eliminated the risk factors of redo groin incision and added easier control of vessels in a clean field. With this procedure being performed more often in the future, these changes will hopefully prove to reduce complications while preserving flow in both the SFA and the PFA.

Objective: In clinical practice, the incidence of femoral pseudoaneurysms requiring repair is small, but at a tertiary care center, the repair rate is higher due to referrals. We sought to specifically study patients who suffered postcatheterization pseudoaneurysms requiring thrombin injection or operative repair and compare them to our routine transfemoral endovascular patients to identify predictors of clinically significant pseudoaneurysms. The underlying goal would be to identify what makes these patients that develop pseudoaneurysms different. Methods: A search of our billing records for Current Procedural Technology (CPT) codes of these 2 procedures between January 2008 and April 2018 was combined with our institution’s Peripheral Vascular Intervention Vascular Quality Initiative database spanning from January 2013 to December 2017. A comparison was then performed between patients who had the outcome of operative intervention for a pseudoaneurysm complication and those who did not, with the goal of elucidating patient demographics and periprocedural factors that would predict pseudoaneurysm formation using univariate and multivariate analyses. Results: There were 77 patients who required thrombin injection or open repair for access-related pseudoaneurysms and 324 patients who did not. Complications occurred more often in patients who were older than 75 (40.2% vs 21.9%; P = .0009), female (57.1% vs 38.6%; P = .003), obese (59.7% vs 33.3%; P < .001), hypertensive (96.1% vs 79.3%; P = .0005), who received a sheath >6F (32.4% vs 13%; P < .0001), intraoperative and postoperative anticoagulation (77.3% vs 32.7% and 52.1% vs 24.2%, respectively; P < .0001), and periprocedural P2Y12 inhibitors (48.7% vs 28%; P = .0005). Less complications were observed in patients who had a closure device used (42.9% vs 8.45%; P < .0001) and protamine reversal (26.5% vs 13.3%; P = .0163). Conclusions: Our findings validate published reports that incriminate a larger sheath size, perioperative anticoagulation, and female gender as increasing the rate of access site complications, with the use of a closure device being protective.

Background Robotic and navigated TKA procedures have been introduced to improve component placement precision in the hope of improving implant survivorship and other clinical outcomes. Although numerous comparative studies have shown enhanced precision and accuracy in placing components, most comparative studies have not shown that such interventions result in improved implant survival. Given what we know about effect sizes from large arthroplasty registries, large cohort studies, and large randomized controlled trials (RCTs), we wondered how large randomized trials would need to be to detect such small differences, and if the number is very high, what that would tell us about the value of these treatments for preventing revision surgery. Questions/purposes In this simulation study, we asked: Given that survivorship differences between technology-assisted TKA (TA-TKA, which we defined as either navigated or robot-assisted TKA) and conventional TKA are either small or absent based on large arthroplasty registries, large cohort studies, and large RCTs, how large would randomized trials need to be to detect small differences between TA-TKA and conventional TKA if they exist, and how long would the follow-up period need to be to have a reasonable chance to detect those differences? Methods We used estimated effect sizes drawn from previous clinical and registry studies, combined with estimates of the accuracy and precision of various navigation and robotic systems, to model and simulate the likely outcomes of potential comparative clinical study designs. To characterize the ranges of patients enrolled and general follow-up times associated with traditional RCT studies, we conducted a structured search of previously published studies evaluating the effect of robotics and navigation on revision rates compared with that of conventional TKA. The structured search of the University of British Columbia's library database (which automatically searches medical publication databases such as PubMed, Embase, Medline, and Web of Science) and subsequent searching through included studies' reference lists yielded 103 search results. Only clinical studies assessing implant survival differences between patient cohorts of TA-TKA and conventional TKA were included. Studies analyzing registry data, using cadaver specimens, assessing revision TKA, conference proceedings, and preprint services were excluded. Twenty studies met all our inclusion criteria, but only one study reported a statistically significant difference between the conventional and robotic or navigated groups. Next, we generated a large set of patients with simulated TKA (1.5 million), randomly assigning each simulated patient a set of patient-specific factors (age at the index surgery, gender, and BMI) drawn from data from registries and published information. We divided this set of simulated procedures into four groups, each associated with a coronal alignment precision reported for different types of surgical procedures, and randomly assigned each patient an overall coronal alignment consistent with their group's precision. TA procedures were modeled based on the alignment precision that an intervention could deliver, regardless of whether the technology used was navigation- or robot-assisted. To evaluate the power associated with using different cohort sizes, we ran a Monte Carlo simulation generating 3000 simulated populations that were drawn (with replacement) from the large set of simulated patients with TKA. We simulated the time to revision for aseptic loosening for each patient, computed the corresponding Kaplan-Meier survival curves, and applied a log-rank test to each study for statistical differences in revision rates at concurrent follow-up timepoints (1-25 years). From each simulation associated with a given cohort size, we determined the percentage of simulated studies that found a statistically significant difference at each follow-up interval. For each alternative precision, we then also calculated the expected reduction in revision rates (effect size) attributable to TA-TKA intervention and the number needed to treat (NNT) using TA-TKA to prevent one revision at 2, 5, 10, and 15 years after index surgery for the entire set of Kaplan-Meier survival analyses. Results The results from our simulation found survivorship differences favoring TA-TKA ranging from 1.4% to 2.0% at 15 years of follow-up. Comparative studies would need to enroll between 2500 and 4000 patients in each arm of the study, depending on the precision of the navigated or robotic procedure, to have an 80% chance of showing this reduction in revision rates at 15 years of follow-up. For the highest precision simulated intervention, the NNT using TA-TKA to prevent one revision was 1000 at 2 years, 334 at 5 years, 100 at 10 years, and 50 at 15 years post-index surgery. Conclusion Based on these simulations, it appears that TA-TKA interventions could potentially result in a relative reduction in revision rates as large as 27% (from 7.5% down to about 5.5% at 15 years for the intervention with the most precise coronal alignment); however, since this 2% absolute reduction in revision rates is relatively small in comparison with the baseline success rate of TKA and would not be realized until 15 years after the index surgery, traditional RCT studies would require excessively large numbers of patients to be enrolled and excessively long follow-up times to demonstrate whether such a reduction actually exists. Clinical relevance Given that the NNTs to avoid revisions at various time points are predicted to be high, it would require correspondingly low system costs to justify broad adoption of TA-TKA based on avoided revision costs alone, though we speculate that technology assistance could perhaps prove to be cost effective in the care of patients who are at an elevated risk of revision.

BACKGROUND: Measuring drilled bore depth in bone is an important part of osteosynthesis surgery. Current methods have substantial limitations in terms of reliability, leading to placement of incorrectly sized screws and unsatisfactory user experience. QUESTIONS/PURPOSES: (1) Can a prototype laser range-finder measure bore depth in bone as well as or better than a conventional depth gauge in terms of accuracy and precision (that is, variability)? METHODS: A conventional analog orthopaedic surgical depth gauge was compared with a laser range-finder-based prototype. Experiments were conducted on four pig hind limbs, with bicortical holes drilled in the femur and the tibia. Two surgeons alternated drilling bores in three different clinically relevant conditions: straight drilling through the diaphysis, angled drilling through the diaphysis, and straight drilling through the metaphysis. Depth measurements were taken with the laser range-finder-based prototype, and the conventional depth gauge and compared against depth measurements obtained from a CT image that served as the reference measurement. RESULTS: In straight diaphyseal drilling the laser range-finder-based prototype had a larger mean error of 1.34 mm (± 0.7 mm) compared with a mean error of -0.06 mm (± 1.38 mm) using the conventional gauge (95% CI 0.824 to 1.976; p < 0.001). In angled diaphyseal drilling, there was no difference in mean error between the laser range-finder-based prototype (1.66 ± 0.86 mm) and the conventional gauge (2.36 ± 3.79 mm [95% CI -2.338 to 0.938]; p = 0.393). In straight metaphyseal drilling, there was no difference in mean error between the laser range-finder-based prototype (2.11 ± 0.8 mm) and the conventional gauge (1.51 ± 3.19 mm [95% CI -0.500 to 1.700]; p = 0.280). The laser range-finder-based prototype had greater precision (smaller variance) than the conventional depth gauge in straight diaphyseal drilling (p < 0.001), angled diaphyseal drilling (p < 0.001), and straight metaphyseal drilling (p < 0.001). CONCLUSIONS: A laser range-finder-based prototype mounted on a conventional surgical drill demonstrated overall similar accuracy and better precision in measuring drilled bore depth in bone compared with the conventional depth gauge. CLINICAL RELEVANCE: A device based on this concept could improve the reliability of bore depth measurement in surgical practice and could therefore reduce the frequency of screw replacement and associated complications.

Although multiple algorithms have been reported that focus on improving the accuracy of 2D–3D registration techniques, there has been relatively little attention paid to quantifying their capture range. In this paper, we analyze the capture range for a number of variant formulations of the 2D–3D registration problem in the context of pedicle screw insertion surgery. We tested twelve 2D–3D registration techniques for capture range under different clinically realistic conditions. A registration was considered as successful if its error was less than 2 mm and 2° in 95% of the cases. We assessed the sensitivity of capture range to a variety of clinically realistic parameters including: X-ray contrast, number and configuration of X-rays, presence or absence of implants in the image, inter-subject variability, intervertebral motion and single-level vs multi-level registration. Gradient correlation + Powell optimizer had the widest capture range and the least sensitivity to X-ray contrast. The combination of 4 AP + lateral X-rays had the widest capture range (725 mm2). The presence of implant projections significantly reduced the registration capture range (up to 84%). Different spine shapes resulted in minor variations in registration capture range (SD 78 mm2). Intervertebral angulations of less than 1.5° had modest effects on the capture range. This paper assessed capture range of a number of variants of intensity-based 2D–3D registration algorithms in clinically realistic situations (for the use in pedicle screw insertion surgery). We conclude that a registration approach based on the gradient correlation similarity and the Powell’s optimization algorithm, using a minimum of two C-arm images, is likely sufficiently robust for the proposed application.

Aims Primary aim: to determine the efficacy of FAST (the Fast Alcohol Screening Test) for detecting harmful and dependent levels of alcohol use. Secondary aim: to compare the performance of the FAST to two short forms of the Alcohol Use Disorder Identification Test (AUDIT): the AUDIT-C and AUDIT-3. Methods Data from 3336 individuals in South Wales, compiled from full AUDIT datasets, were examined. AUROC analysis, alongside measures of sensitivity and specificity of the FAST, AUDIT-C and AUDIT-3 were utilized for the identification of harmful and dependent alcohol use. Results The FAST demonstrated efficacy in the identification of harmful and dependent levels of alcohol use, with superior performance to both the AUDIT-C and AUDIT-3. Conclusion The present paper demonstrates the potential of the FAST as a cost- and time-effective method for appropriate screening and signposting in the stepped care model utilized by many health care and treatment services. Further studies are needed to ensure validity, both within the general population and for specific services and populations., Short Summary: The FAST (Fast Alcohol Screening Test) (a brief screen for alcohol consumption, dependence and harm) demonstrates efficacy in its ability to identify and distinguish between both harmful and severely dependent tiers of alcohol use, within a population which predominantly exhibits risk-related alcohol usage. The FAST exhibits superior performance, in this respect, to the AUDIT-C and AUDIT-3 (which measure consumption only), providing additional evidence to further highlight the importance of not solely relying on alcohol consumption to classify tiers of harm.

Estimating uncertainty in predictions made by neural networks is critically important for increasing the trust medical experts have in automatic data analysis results. In segmentation tasks, quantifying levels of confidence can provide meaningful additional information to aid clinical decision making. In recent work, we proposed an interpretable uncertainty measure to aid clinicians in assessing the reliability of developmental dysplasia of the hip metrics measured from 3D ultrasound screening scans, as well as that of the US scan itself. In this work, we propose a technique to quantify confidence in the associated segmentation process that incorporates voxel-wise uncertainty into the binary loss function used in the training regime, which encourages the network to concentrate its training effort on its least certain predictions. We propose using a Bayesian-based technique to quantify 3D segmentation uncertainty by modifying the loss function within an encoder-decoder type voxel labeling deep network. By appending a voxel-wise uncertainty measure, our modified loss helps the network improve prediction uncertainty for voxels that are harder to train. We validate our approach by training a Bayesian 3D U-Net with the proposed modified loss function on a dataset comprising 92 clinical 3D US neonate scans and test on a separate hold-out dataset of 24 patients. Quantitatively, we show that the Dice score of ilium and acetabulum segmentation improves by 5% when trained with our proposed voxel-wise uncertainty loss compared to training with standard cross-entropy loss. Qualitatively, we further demonstrate how our modified loss function results in meaningful reduction of voxel-wise segmentation uncertainty estimates, with the network making more confident accurate predictions. We proposed a Bayesian technique to encode voxel-wise segmentation uncertainty information into deep neural network optimization, and demonstrated how it can be leveraged into meaningful confidence measures to improve the model’s predictive performance.

Heat stress, an environmental and occupational hazard, is associated with a spectrum of heat-related illnesses, including heat stroke, which can lead to death. CDC's National Institute for Occupational Safety and Health (NIOSH) publishes recommended occupational exposure limits for heat stress (1). These limits, which are consistent with those of the American Conference of Governmental Industrial Hygienists (ACGIH) (2), specify the maximum combination of environmental heat (measured as wet bulb globe temperature [WBGT]) and metabolic heat (i.e., workload) to which workers should be exposed. Exposure limits are lower for workers who are unacclimatized to heat, who wear work clothing that inhibits heat dissipation, and who have predisposing personal risk factors (1,2). These limits have been validated in experimental settings but not at outdoor worksites. To determine whether the NIOSH and ACGIH exposure limits are protective of workers, CDC retrospectively reviewed 25 outdoor occupational heat-related illnesses (14 fatal and 11 nonfatal) investigated by the Occupational Safety and Health Administration (OSHA) from 2011 to 2016. For each incident, OSHA assessed personal risk factors and estimated WBGT, workload, and acclimatization status. Heat stress exceeded exposure limits in all 14 fatalities and in eight of 11 nonfatal illnesses. An analysis of Heat Index data for the same 25 cases suggests that when WBGT is unavailable, a Heat Index screening threshold of 85°F (29.4°C) could identify potentially hazardous levels of workplace environmental heat. Protective measures should be implemented whenever the exposure limits are exceeded. The comprehensive heat-related illness prevention program should include an acclimatization schedule for newly hired workers and unacclimatized long-term workers (e.g., during early-season heat waves), training for workers and supervisors about symptom recognition and first aid (e.g., aggressive cooling of presumed heat stroke victims before medical professionals arrive), engineering and administrative controls to reduce heat stress, medical surveillance, and provision of fluids and shady areas for rest breaks.

The purposes of this study were to (1) perform a systematic review of articles that reported agreement or reproducibility in repeated diagnosis of developmental dysplasia of the hip (DDH) using ultrasound imaging, (2) estimate the reproducibility in the available dysplasia metrics, and (3) compare reproducibility of the available dysplasia metrics.A systematic review of the Medline and Embase databases was performed by using a search strategy formulated from our research question: "For infants at risk of DDH, are US imaging-based diagnoses reproducible?" Two reviewers independently identified articles for inclusion in the systematic review, and then assessed the quality of the included studies using the Guidelines for Reporting Reliability and Agreement Studies guideline. Variability and agreement-related statistics in the included studies were extracted and included in a meta-analysis for summarizing the available statistics. The reproducibility of the available dysplasia metrics was compared, with a Bonferroni correction made to adjust for multiple comparisons.Twenty eight studies were included in the systematic review. Overall, the quality of the included studies was moderate (average, 10.7/15; range, 6 to 12). Graf's alpha angle had the lowest interexamination variability of the metrics assessed, followed by Graf's beta angle (the variability of the alpha angle was 10% lower than the variability of the beta angle, P0.05). However, despite Graf's angles having lower variability compared with other dysplasia metrics, their actual variability was still problematically high. This finding was supported by the low intraclass correlation and Kappa coefficient values reported in the included studies. There was also evidence to suggest that the reproducibility in DDH diagnosis has potentially worsened over time.Overall, we found high variability and low agreement in all reported dysplasia metrics. Furthermore, in the last 3 decades, the repeatability of dysplasia metrics has not markedly improved and may even have declined, indicating a genuine need for improving repeatability and reliability of ultrasound-based DDH diagnosis.Level III-systematic review of level III studies.

Background Endovascular aneurysm repair (EVAR) and Thoracic endovascular aortic repair (TEVAR) are commonly performed by interventional radiologists, cardiologists, general surgeons, cardiothoracic surgeons, and vascular surgeons, with each specialty having differences in residency structure, operative experience, and subspecialty training. The aim of this study is to evaluate the impact of surgeon specialty on outcomes following EVAR and TEVAR. Methods Patients who underwent EVAR and TEVAR were identified from the 2007 to 2009 Nationwide Inpatient Sample (NIS). Physician identifiers in the NIS were used to determine surgical specialty and operative experience. Multivariate analysis adjusted for mortality risk was used to compare differences in demographics, complications, outcomes, and hospital covariates. Results A total of 5147 EVARs were identified within the NIS, of which 88.3% were completed by vascular surgeons. There were no significant differences in demographics between the specialties. Cardiothoracic surgeons were more likely to have a postoperative stroke (3.1% vs. 0.2%, odds ratio [OR] 14.6, 95% confidence interval [CI] 1.8–117.8, P

This scoping review considered the role of chaplains with regard to 'moral injury'. Moral injury is gaining increasing notoriety. This is due to greater recognition that trauma (in its various forms) can cause much deeper inflictions and afflictions than just physiological or psychological harm, for there may also be wounds affecting the 'soul' that are far more difficult to heal-if at all. As part of a larger research program exploring moral injury, a scoping review of literature and other resources was implemented utilising Arksey and O'Malley's scoping method (Int J Soc Res Methodol 8(1):19-32, 2005) to focus upon moral injury, spirituality (including religion) and chaplaincy. Of the total number of articles and/or resources noting the term 'moral injury' in relation to spiritual/religious issues (n = 482), the results revealed 60 resources that specifically noted moral injury and chaplains (or other similar bestowed title). The majority of these resources were clearly positive about the role (or the potential role) of chaplains with regard to mental health issues and/or moral injury. The World Health Organization International Classification of Diseases: Australian Modification of Health Interventions to the International Statistical Classification of Diseases and related Health problems (10th revision, vol 3-WHO ICD-10-AM, Geneva, 2002), was utilised as a coding framework to classify and identify distinct chaplaincy roles and interventions with regard to assisting people with moral injury. Several recommendations are made concerning moral injury and chaplaincy, most particularly the need for greater research to be conducted.

Biological systems, at all scales of organisation from nucleic acids to ecosystems, are inherently complex and variable. Biologists therefore use statistical analyses to detect signal among this systemic noise. Statistical models infer trends, find functional relationships and detect differences that exist among groups or are caused by experimental manipulations. They also use statistical relationships to help predict uncertain futures. All branches of the biological sciences now embrace the possibilities of mixed-effects modelling and its flexible toolkit for partitioning noise and signal. The mixed-effects model is not, however, a panacea for poor experimental design, and should be used with caution when inferring or deducing the importance of both fixed and random effects. Here we describe a selection of the perils and pitfalls that are widespread in the biological literature, but can be avoided by careful reflection, modelling and model-checking. We focus on situations where incautious modelling risks exposure to these pitfalls and the drawing of incorrect conclusions. Our stance is that statements of significance, information content or credibility all have their place in biological research, as long as these statements are cautious and well-informed by checks on the validity of assumptions. Our intention is to reveal potential perils and pitfalls in mixed model estimation so that researchers can use these powerful approaches with greater awareness and confidence. Our examples are ecological, but translate easily to all branches of biology.

Pedicle screw fixation is a challenging procedure with a concerning rates of reoperation. After insertion of the screws is completed, the most common intraoperative verification approach is to acquire anterior–posterior and lateral radiographic images, based on which the surgeons try to visually assess the correctness of insertion. Given the limited accuracy of the existing verification techniques, we identified the need for an accurate and automated pedicle screw assessment system that can verify the screw insertion intraoperatively. For doing so, this paper offers a framework for automatic segmentation and pose estimation of pedicle screws based on deep learning principles. Segmentation of pedicle screw X-ray projections was performed by a convolutional neural network. The network could isolate the input X-rays into three classes: screw head, screw shaft and background. Once all the screw shafts were segmented, knowledge about the spatial configuration of the acquired biplanar X-rays was used to identify the correspondence between the projections. Pose estimation was then performed to estimate the 6 degree-of-freedom pose of each screw. The performance of the proposed pose estimation method was tested on a porcine specimen. The developed machine learning framework was capable of segmenting the screw shafts with 93% and 83% accuracy when tested on synthetic X-rays and on clinically realistic X-rays, respectively. The pose estimation accuracy of this method was shown to be $$1.93^{\circ } \pm 0.64^{\circ }$$ and $$1.92 \pm 0.55\,\hbox {mm}$$ on clinically realistic X-rays. The proposed system offers an accurate and fully automatic pedicle screw segmentation and pose assessment framework. Such a system can help to provide an intraoperative pedicle screw insertion assessment protocol with minimal interference with the existing surgical routines.

Ultrasound (US) is a safer alternative to X-rays for bone imaging, and its popularity for orthopedic surgical navigation is growing. Routine use of intraoperative US for navigation requires fast, accurate and automatic alignment of tracked US to preoperative computed tomography (CT) patient models. Our group previously investigated image segmentation and registration to align untracked US to CT of only the partial pelvic anatomy. In this paper, we extend this to study the performance of these previously published techniques over the full pelvis in a tracked framework, to characterize their suitability in more realistic scenarios, along with an additional simplified segmentation method and similarity metric for registration. We evaluated phase symmetry segmentation, and Gaussian mixture model (GMM) and coherent point drift (CPD) registration methods on a pelvic phantom augmented with human soft tissue images. Additionally, we proposed and evaluated a simplified 3D bone segmentation algorithm we call Shadow–Peak (SP), which uses acoustic shadowing and peak intensities to detect bone surfaces. We paired this with a registration pipeline that optimizes the normalized cross-correlation (NCC) between distance maps of the segmented US–CT images. SP segmentation combined with the proposed NCC registration successfully aligned tracked US volumes to the preoperative CT model in all trials, in contrast to the other techniques. SP with NCC achieved a median target registration error (TRE) of 2.44 mm (maximum 4.06 mm), when imaging all three anterior pelvic structures, and a mean runtime of 27.3 s. SP segmentation with CPD registration was the next most accurate combination: median TRE of 3.19 mm (maximum 6.07 mm), though a much faster runtime of 4.2 s. We demonstrate an accurate, automatic image processing pipeline for intraoperative alignment of US–CT over the full pelvis and compare its performance with the state-of-the-art methods. The proposed methods are amenable to clinical implementation due to their high accuracy on realistic data and acceptably low runtimes.

The use of linear mixed effects models (LMMs) is increasingly common in the analysis of biological data. Whilst LMMs offer a flexible approach to modelling a broad range of data types, ecological data are often complex and require complex model structures, and the fitting and interpretation of such models is not always straightforward. The ability to achieve robust biological inference requires that practitioners know how and when to apply these tools. Here, we provide a general overview of current methods for the application of LMMs to biological data, and highlight the typical pitfalls that can be encountered in the statistical modelling process. We tackle several issues relating to the use of information theory and multi-model inference in ecology, and demonstrate the tendency for data dredging to lead to greatly inflated Type I error rate (false positives) and impaired inference. We offer practical solutions and direct the reader to key references that provide further technical detail for those seeking a deeper understanding. This overview should serve as a widely accessible code of best practice for applying LMMs to complex biological problems and model structures, and in doing so improve the robustness of conclusions drawn from studies investigating ecological and evolutionary questions.

Pedicle screw malplacement, leading to neurological symptoms, vascular injury, and premature implant loosening, is not uncommon and difficult to reliably detect intraoperatively with current techniques. We propose a new intraoperative post-placement pedicle screw position assessment system that can therefore allow surgeons to correct breaches during the procedure. Our objectives were to assess the accuracy and robustness of this proposed screw location system and to compare its performance to that of 2D planar radiography. The proposed system uses two intraoperative X-ray shots acquired with a standard fluoroscopic C-arm and processed using 2D/3D registration methods to provide a 3D visualization of the vertebra and screw superimposed on one another. Point digitization and CT imaging of the residual screw tunnel were used to assess accuracy in five synthetic lumbar vertebral models (10 screws in total). Additionally, the accuracy was evaluated with and without correcting for image distortion and for various screw lengths, screw materials, breach directions, and vertebral levels. The proposed method is capable of localizing the implanted screws with less than 2 mm of translational error (RMSE: 0.7 and 0.8 mm for the screw head and tip, respectively) and less than $$2.3^{\circ }$$ angular error (RMSE: $$1.3^{\circ }$$ ), with minimal change to the errors if image distortion is not corrected. Breaches and their anatomical locations were all correctly visualized and identified for a variety of screw lengths, screw materials, breach locations, and vertebral levels, demonstrating the robustness of this approach. In contrast, one breach, one non-breach, and the anatomical location of three screws were misclassified with 2D X-ray. We have demonstrated an accurate and low-radiation technique for localizing pedicle screws post-implantation that requires only two X-rays. This intraoperative feedback of screw location and direction may allow the surgeon to correct malplaced screws intraoperatively, thereby reducing postoperative complications and reoperation rates.

In some plant-insect interactions, specialist herbivores exploit the chemical defenses of their food plant to their own advantage. Brassica plants produce glucosinolates that are broken down into defensive toxins when tissue is damaged, but the specialist aphid, Brevicoryne brassicae, uses these chemicals against its own natural enemies by becoming a "walking mustard-oil bomb". Analysis of glucosinolate concentrations in plant tissue and associated aphid colonies reveals that not only do aphids sequester glucosinolates, but they do so selectively. Aphids specifically accumulate sinigrin to high concentrations while preferentially excreting a structurally similar glucosinolate, progoitrin. Surveys of aphid infestation in wild populations of Brassica oleracea show that this pattern of sequestration and excretion maps onto host plant use. The probability of aphid infestation decreases with increasing concentrations of progoitrin in plants. Brassica brassicae, therefore, appear to select among food plants according to plant secondary metabolite profiles, and selectively store only some compounds that are used against their own enemies. The results demonstrate chemical and behavioral mechanisms that help to explain evidence of geographic patterns and evolutionary dynamics in Brassica-aphid interactions.

3D ultrasound (US) imaging has the potential to become a powerful alternative imaging modality in orthopaedic surgery as it is radiation-free and can produce 3D images (in contrast to fluoroscopy) in near-real time. Conventional B-mode US images, however, are characterized by high levels of noise and reverberation artifacts, image quality is user-dependent, and bone surfaces are blurred, which makes it difficult to both interpret images and to use them as a basis for navigated interventions. 3D US has great potential to assist orthopaedic care, possibly assisting during surgery if the anatomical structures of interest could be localized and visualized with sufficient accuracy and clarity and in a highly automated rapid manner.In this paper, we present clinical results for a novel 3D US segmentation technique we have recently developed based on multi-resolution analysis to localize bone surfaces in 3D US volumes. Our method is validated on scans obtained from 29 trauma patients with distal radius and pelvic ring fractures.Qualitative and quantitative results demonstrate remarkably clear segmentations of bone surfaces with an average surface fitting error of 0.62 mm (standard deviation (SD) of 0.42 mm) for pelvic patients and 0.21 mm (SD 0.14 mm) for distal radius patients.These results suggest that our technique is sufficiently accurate for potential use in orthopaedic trauma applications.

Gail Powell-Cope, PhD, ARNP, FAANPeter Toyinbo, PhDNitin Patel, MPHDeborah Rugs, PhDChristine Elnitsky, PhD, RNBridget Hahm, MA, MPHBryce Sutton, PhDRobert Campbell, PhDKaren Besterman-Dahan, PhDMary Matz, MSPH, CPE, CSPHPMichael Hodgson, MD, MPHOBJECTIVE: Theobjectiveofthestudywastoidentifywhichcomponentsof asystem-wide safepatienthand-ling(SPH)programreducedmusculoskeletalinjury(MSI) due to patient handling among nurses.METHODS: The3-yearlongitudinalstudyfrom2008to2011usedapretest-posttestdesign.ThestudywasconductedintheVeteransHealthAdministration,andallmedicalcentersparticipated.Theoutcomewas2011MSI incidence rates due to patient-related handlingfor nurses, expressed as injuries per 10000 full-timeemployees.RESULTS: Threeorganizationalriskfactors,beddaysof care, facility complexity level, and baseline MSIincidence rate, were significantly associated with MSIincidencerateandexplained21%ofitsvariation.FiveSPHcomponents,includingdeploymentofceilingliftsand other new technologies, peer leader effectiveness,competencyinSPHequipmentuse,facilitycoordinatorlink with safety committee, and peer leader training,uniquelyaccountedforanadditional23%ofthetotalvariation.CONCLUSIONS: Findings provide evidence to sup-port the effectiveness of a multicomponent approachto SPH programs given contextual considerations.Healthcare workers responsible for manual patienthandling,particularlynursesandnursingassistants(NAs), have among the highest rates of nonfatal occu-pational injuries requiring days away from work.

Context: In the United States, regional poison centers frequently receive calls about toxic workplace exposures. Most poison centers do not share call details routinely with governmental regulatory agencies. Worker health and safety could be enhanced if regulators such as the Occupational Safety and Health Administration (OSHA) had the ability to investigate these events and prevent similar incidents. With this goal in mind, the Georgia Poison Center (GPC) began referring occupational exposures to OSHA in July 2014. Methods: GPC began collecting additional employer details when handling occupational exposure calls. When workers granted permission, GPC forwarded call details to the OSHA Regional Office in Atlanta. These referrals enabled OSHA to initiate several investigations. We also analyzed all occupational exposures reported to GPC during the study period to characterize the events, detect violations of OSHA reporting requirements, and identify hazardous scenarios that could form the basis for future OSHA rulemaking or guidance. Results: GPC was informed about 953 occupational exposures between 1 July, 2014 and 7 January, 2016. Workers were exposed to 217 unique substances, and 70.3% of victims received treatment in a healthcare facility. Hydrogen sulfide was responsible for the largest number of severe clinical effects. GPC obtained permission to refer 89 (9.3%) calls to OSHA. As a result of these referrals, OSHA conducted 39 investigations and cited 15 employers for “serious” violations. OSHA forwarded several other referrals to other regulatory agencies when OSHA did not have jurisdiction. At least one employer failed to comply with OSHA’s new rule that mandates reporting of all work-related hospitalizations. This collaboration increased OSHA’s awareness of dangerous job tasks including hydrofluoric acid exposure among auto detailers and carbon monoxide poisoning with indoor use of gasoline-powered tools. Conclusions: Collaboration with the GPC generated a useful source of referrals to OSHA. OSHA investigations led to abatement of existing hazards, and OSHA acquired new knowledge of occupational exposure scenarios.

There is substantial evidence that genetic variation, at both the level of the individual and population, has a significant effect on behaviour, fitness and response to toxicants. Using DNA microsatellites, we examined the genetic variation in samples of several commonly used laboratory strains of zebrafish, Danio rerio, a model species in toxicological studies. We compared the genetic variation to that found in a sample of wild fish from Bangladesh. Our findings show that the wild fish were significantly more variable than the laboratory strains for several measures of genetic variability, including allelic richness and expected heterozygosity. This lack of variation should be given due consideration for any study which attempts to extrapolate the results of ecotoxicological laboratory tests to wild populations.

The operative findings are presented in two patients following inadequate coil embolization. At craniotomy, part of the coil mass had extruded through the fundus of both aneurysms. It is unclear if this phenomenon is confined to aneurysms that demonstrate significant regrowth and if there is an increased risk of rebleeding.

In last year's conference, we presented adiscussion of the relevance of the "Innovation Agenda"for engineering education. In the current paper, wepresent an overview from the literature of what isunderstood about the effectiveness of teaching innovationand entrepreneurship in order to prompt discussion aboutpotential implications for engineering curriculum design.

UBC has held two NSERC Chairs in Design Engineering through which we have established connections with the Sauder School of Business (through our New Venture Design program) and other engineering departments (through our multidisciplinary capstone design course). We are now planning a renewal application for our Design Chair that aims to extend the scope of designrelated work at UBC by establishing a graduate program in Technical Product Innovation (TPI) that will connect Applied Science, the Business School, Computer Science and Industrial Design at the Emily Carr University of Art and Design. The TPI program will offer both thesis and non-thesis degree options at the master's level, along with a concentration certificate that will be available to non- TPI students. The curriculum will have five key components: (1) a technical base in the area of the student's undergraduate specialization, (2) courses in innovation theory and entrepreneurship in collaboration with the Sauder School, (3) courses in human factors engineering in collaboration with computer science, (4) special 'passport-style' skills-based courses in prototyping, visual communication and user evaluation in collaboration with industrial design, and (5) project and thesis options that will allow for work on industry- or entrepreneurship-based design projects. The goal of the proposed program will be to train students to take on leadership roles in product development programs in both startups and established companies. The TPI program will initially focus on three key areas: medical technologies, consumer products and business-to-business products. It will build on two significant cross-university initiatives - the multi-faculty Human-Computer Interaction interest group (hci@ubc) and the universitywide Entrepreneurship@UBC program - and will tie into related emerging initiatives such as the Innovation Hub at Vancouver General Hospital and Wearables@UBC.

Deterministic dynamic models for coupled resident and invader populations are considered with the purpose of finding quantities that are effective at predicting when the invasive population will become established asymptotically. A key feature of the models considered is the stage-structure, meaning that the populations are described by vectors of discrete developmental stage- or age-classes. The vector structure permits exotic transient behaviour-phenomena not encountered in scalar models. Analysis using a linear Lyapunov function demonstrates that for the class of population models considered, a large so-called population inertia is indicative of successful invasion. Population inertia is an indicator of transient growth or decline. Furthermore, for the class of models considered, we find that the so-called invasion exponent, an existing index used in models for invasion, is not always a reliable comparative indicator of successful invasion. We highlight these findings through numerical examples and a biological interpretation of why this might be the case is discussed.

The purpose of this study is to describe our initial experience of imaging adults with localisation-related epilepsy using MR imaging at 3.0T. We discuss the findings in the context of the recently released NICE guidelines that provide detailed advice on imaging people with epilepsy in the UK. 120 consecutive people over the age of 16 years with localisation-related epilepsy were referred for clinical MR examinations from a regional neuroscience centre in England. None of the people had had MR examinations prior to the present study. High resolution MR imaging was performed taking advantage of the high field strength and high performance gradients of the system. Two experienced neuroradiologists reported on the examinations independently and the presence and type of pathology was recorded. There was complete agreement between the two reporters in all 120 cases. The overall frequency of abnormalities shown by MR was 31/120 (26%) and the commonest abnormality shown was mesial temporal sclerosis found in 10/120 (8%). Tumours were shown in 4/120, all of which appeared low grade as judged by imaging criteria. Epilepsy is the commonest neurological condition and demands a significant resource in order to provide good care for sufferers. Recent guidelines published in the UK have suggested that the majority of people with epilepsy should receive brain MR as part of their routine assessment. Our work shows that using the most sophisticated MR imaging in a highly selected population there is a modest pick-up rate of brain abnormalities. If a widespread epilepsy-imaging programme is started the detection rate is likely to be much lower. Although MR is acknowledged to be a reliable way of detecting pathology in people with epilepsy there is a dearth of information studying the health economics of imaging epilepsy in relation to patient management and outcomes.

The purpose of this paper is to report the use of a covered stent-graft in the endovascular treatment of a surgically created arteriovenous fistula. A 37-year-old woman with symptomatic venous ambulatory hypertension underwent a left common femoral vein-to-right common iliac vein bypass using 10 mm ringed polytetrafluoroethylene (PTFE) with creation of an arteriovenous (AV) fistula from the superficial femoral artery to the PTFE graft. At 1 year postoperatively, recurrent symptoms thought to be due to the arteriovenous fistula were treated by placement of an 8 mm x 10 cm Viabahn covered stent-graft. Placement was via crossover technique from the right common femoral artery using a 9 French sheath. At 2 months' follow-up symptoms had resolved, the AV fistula was occluded, and venous bypass remained patent. Focal arteriovenous fistulas of the proximal superficial femoral artery can be treated safely with a covered stent-graft via an endovascular approach.

Anesthetic techniques vary widely in the endovascular repair of abdominal aortic aneurysms (EVAR). Previous studies have demonstrated the feasibility of using local anesthesia. However, the ideal anesthetic technique has not been determined. This study examines whether anesthetic technique influences the outcomes of EVAR. Data regarding demographics, risk factors, procedural characteristics, recovery characteristics, treatment complications, acute (30 day) medical complications, mortality, and anesthetic type were prospectively collected during the AneuRx phase II aortic endograft trial. Patient cohorts receiving general, regional, or local anesthesia were compared. From 1997 to 1998, 424 patients underwent EVAR at 13 sites using the AneuRx Bifurcated endograft. There were 279 patients in the general anesthesia group, 95 patients in the regional group, and 50 patients in the local group. Risk factors were similar. There were no significant differences in age, gender, American Society of Anesthesiologists grade, length of anesthesia, branch artery occlusions, proximal endoleaks, failed implants, or open surgical conversions. Cardiac, renal, and wound-healing complications were all lower in the local group. Mortality was equivalent among the three groups. (p0.05, ANOVA). From these results we concluded that EVAR with local anesthesia is a safe and efficacious method that may reduce recovery times and postoperative medical morbidity compared to use of general or spinal/epidural anesthesia.

GrassView - the form and function of grass is an interactive computer programme which uses video footage, narration, sound, computer based 3D animation, graphical displays of information, charts and quizzes to present a description of the morphology of a grass tiller and the implications for sward behaviour. The programme is designed for flexibility of use. In interactive mode it could be used for self-directive study, whereas in linear mode it could be video-projected as a presentation to a class of students or to an assembled group. It has been optimised to run under Windows 95 or NT 4.0 and is distributed as a CD. Keywords: computer program, grass form and function, grass morphology, interactive program, leaf extension

This contribution moves in the direction of answering some general questions about the most effective and useful ways of modelling bioprocesses. We investigate the characteristics of models that are good at extrapolating. We trained three fully predictive models with different representational structures (differential equations, differential equations with inheritance of rates and a network of reactions) on Saccharopolyspora erythraea shake flask fermentation data using genetic programming. The models were then tested on unseen data outside the range of the training data and the resulting performances were compared. It was found that constrained models with mathematical forms analogous to internal mass balancing and stoichiometric relations were superior to flexible unconstrained models, even though no a priori knowledge of this fermentation was used.

The objective of this study was to characterize patient demographics, risk factors, and anatomic distribution of upper extremity deep venous thrombosis (UEDVT) to develop a probability model for diagnosis. A retrospective review of all patients who underwent color-flow duplex scanning (CDS) for clinically suspected acute UEDVT over a 5-year period was performed. Patient risk factors and clinical symptoms were evaluated as predictors. Technically adequate complete CDS of 177 upper extremities (UEs) of arms were reviewed. CDS scanning identified acute UE venous thrombosis in 53 (30%) of the arms examined with deep system involvement in 40 (23%). Of the UEs affected, the subclavian was involved in 64%, the axillary in 25%, the internal jugular in 32%, the brachial in 36%, the cephalic in 32%, and the basilic in 47%. Multivariate analysis identified limb tenderness (odds ratio 9.3), history of central venous catheterization (odds ratio 7.0), and malignancy (odds ratio 2.9) as positive predictors for UEDVT. Erythema (odds ratio 0.12) and suspected pulmonary embolism (odds ration 0.06) were identified as negative predictors. A predictive model was designed from these variables. The anatomic distribution of UEDVT obtained from this study is consistent with previous reviews. Potential positive and negative risk factors can be identified from which a predictive model can be designed. Use of this model can help focus clinical suspicion, improve color-flow duplex utilization, and provide timely treatment with anticoagulation.

This paper describes the analysis of recombinant factor VIIa (rFVIIa; NovoSeven; Novo Nordisk, Bagsvaerd, Denmark) use in 40 patients with intractable bleeding in the UK. All cases were reported on the 'rFVIIa extended use database' (Traumanet) between its launch in February 1999 and 12 March 2002. Twenty-one other cases reporting rFVIIa use in different circumstances were excluded from the analysis. Recombinant FVIIa was effective in stopping or markedly reducing blood loss in 80% of patients; 20% of patients did not respond to treatment. Non-responders tended to have more deranged coagulation and lower platelet counts compared with responders. Despite a wide range of underlying illnesses, including malignancy and sepsis, few patients suffered adverse events. Thrombotic events occurred in three of 40 (7.5%) patients and these patients were considered as already at risk of thrombosis from other causes. The data suggest that rFVIIa is safe and effective therapy in patients with uncontrollable haemorrhage.

The preservation of internal iliac artery (IIA) flow during endovascular repair of abdominal aortic aneurysms (er-AAA) remains a controversial area. Ectasia and aneurysmal disease of the iliac arteries represent a formidable challenge to the endovascular surgeon, particularly when aortic neck length and diameter are suitable for er-AAA. We describe a procedure to maintain arterial perfusion to the pelvis during er-AAA called retrograde endovascular hypogastric artery preservation (REHAP). This technique is particularly useful in the presence of common iliac artery (CIA) and internal iliac artery (IIA) aneurysms when pelvic perfusion to one IIA needs to be maintained. A Wallgraft is first placed from the IIA to the ipsilateral EIA followed by er-AAA using an aortouniiliac graft (AUI) and a femorofemoral bypass graft (BPG). This procedure represents one alternative to maintaining pelvic perfusion using standard endovascular and surgical techniques.