An autonomous X-ray image acquisition and interpretation system for assisting percutaneous pelvic fracture fixation

PURPOSE

Percutaneous fracture fixation involves multiple X-ray acquisitions to determine adequate tool trajectories in bony anatomy. In order to reduce time spent adjusting the X-ray imager's gantry, avoid excess acquisitions, and anticipate inadequate trajectories before penetrating bone, we propose an autonomous system for intra-operative feedback that combines robotic X-ray imaging and machine learning for automated image acquisition and interpretation, respectively.

METHODS

Our approach reconstructs an appropriate trajectory in a two-image sequence, where the optimal second viewpoint is determined based on analysis of the first image. A deep neural network is responsible for detecting the tool and corridor, here a K-wire and the superior pubic ramus, respectively, in these radiographs. The reconstructed corridor and K-wire pose are compared to determine likelihood of cortical breach, and both are visualized for the clinician in a mixed reality environment that is spatially registered to the patient and delivered by an optical see-through head-mounted display.

RESULTS

We assess the upper bounds on system performance through in silico evaluation across 11 CTs with fractures present, in which the corridor and K-wire are adequately reconstructed. In post hoc analysis of radiographs across 3 cadaveric specimens, our system determines the appropriate trajectory to within 2.8 ± 1.3 mm and 2.7 ± 1.8[Formula: see text].

CONCLUSION

An expert user study with an anthropomorphic phantom demonstrates how our autonomous, integrated system requires fewer images and lower movement to guide and confirm adequate placement compared to current clinical practice. Code and data are available.

From diversity to complexity: Microbial networks in soils

Network analysis has been used for many years in ecological research to analyze organismal associations, for example in food webs, plant-plant or plant-animal interactions. Although network analysis is widely applied in microbial ecology, only recently has it entered the realms of soil microbial ecology, shown by a rapid rise in studies applying co-occurrence analysis to soil microbial communities. While this application offers great potential for deeper insights into the ecological structure of soil microbial ecosystems, it also brings new challenges related to the specific characteristics of soil datasets and the type of ecological questions that can be addressed. In this Perspectives Paper we assess the challenges of applying network analysis to soil microbial ecology due to the small-scale heterogeneity of the soil environment and the nature of soil microbial datasets. We review the different approaches of network construction that are commonly applied to soil microbial datasets and discuss their features and limitations. Using a test dataset of microbial communities from two depths of a forest soil, we demonstrate how different experimental designs and network constructing algorithms affect the structure of the resulting networks, and how this in turn may influence ecological conclusions. We will also reveal how assumptions of the construction method, methods of preparing the dataset, and definitions of thresholds affect the network structure. Finally, we discuss the particular questions in soil microbial ecology that can be approached by analyzing and interpreting specific network properties. Targeting these network properties in a meaningful way will allow applying this technique not in merely descriptive, but in hypothesis-driven research. Analysing microbial networks in soils opens a window to a better understanding of the complexity of microbial communities. However, this approach is unfortunately often used to draw conclusions which are far beyond the scientific evidence it can provide, which has damaged its reputation for soil microbial analysis. In this Perspectives Paper, we would like to sharpen the view for the real potential of microbial co-occurrence analysis in soils, and at the same time raise awareness regarding its limitations and the many ways how it can be misused or misinterpreted.

Psychedelics as Novel Therapeutics in Alzheimer's Disease: Rationale and Potential Mechanisms

Serotonin 2A receptor (5-HT_2AR) agonist "classic psychedelics" are drawing increasing interest as potential mental health treatments. Recent work suggests psychedelics can exert persisting anxiolytic and antidepressant effects lasting up to several months after a single administration. Data indicate acute subjective drug effects as important psychological factors involved in observed therapeutic benefits. Additionally, animal models have shown an important role for 5-HT_2AR agonists in modulating learning and memory function with relevance for Alzheimer's Disease (AD) and related dementias. A number of biological mechanisms of action are under investigation to elucidate 5-HT_2AR agonists' therapeutic potential, including enhanced neuroplasticity, anti-inflammatory effects, and alterations in brain functional connectivity. These diverse lines of research are reviewed here along with a discussion of AD pathophysiology and neuropsychiatric symptoms to highlight classic psychedelics as potential novel pharmacotherapies for patients with AD. Human clinical research suggests a possible role for high-dose psychedelic administration in symptomatic treatment of depressed mood and anxiety in early-stage AD. Preclinical data indicate a potential for low- or high-dose psychedelic treatment regimens to slow or reverse brain atrophy, enhance cognitive function, and slow progression of AD. In conclusion, rationale and potential approaches for preliminary research with psychedelics in patients with AD are presented, and ramifications of this line of investigation for development of novel AD treatments are discussed.

Rescuing the Emergency – Multiple Expertise and IT in the Emergency Field

Objectives: The rapid growth, both in technical and social approaches to the innovation phenomenon in health care suggests that profound changes are occurring. The focus of the project was to evaluate these changes through the case study of the French emergency field.

Methods: The consequences of information technology implementations in the Emergency Services are presented as models to investigate the importance of technical expertise, with both the involvement of all the stakeholders from the beginning of the design and the test of the new tool in real settings.

Results and Conclusion: A new form of work resulted for the management of the crisis, which questioned the status of the actors and their actions, and the characteristics of the protocols of rescue. The outcome of this project was a new model built for the rescue of the emergency field which encompasses alternative forms of expertise.

Single-lumen and multi-lumen poly(ethylene glycol) nerve conduits fabricated by stereolithography for peripheral nerve regeneration in vivo

BACKGROUND

The use of nerve conduits to facilitate nerve regrowth after peripheral nerve injury is limited to defects less than 3 cm. The purpose of this study is to determine the capability of novel single and multi-lumen poly(ethylene glycol) (PEG) conduits manufactured by stereolithography to promote peripheral nerve regeneration.

MATERIALS AND METHODS

Eight Sprague Dawley rats with sharp transection injuries of the sciatic nerve were randomly assigned to receive single-lumen or multi-lumen PEG conduits to bridge a 10-mm gap. Sciatic nerve and conduit samples were harvested after 5 weeks, and axon number, myelin thickness, fiber diameter, and g-ratio were analyzed. The contralateral intact nerve was also harvested for comparison.

RESULTS

Partial nerve regeneration was observed in three out of four single-lumen conduits and one out of four multi-lumen conduits. Axon number in the single-lumen regenerated nerve approached that of the contralateral intact nerve at 4,492 ± 2,810.0 and 6,080 ± 627.9 fibers/mm(2), respectively. The percentage of small fibers was greater in the single-lumen conduit compared with the intact nerve, whereas myelin thickness and g-ratio were consistently greater in the autologous nerve. Axon regrowth through the multi-lumen conduits was severely limited.

CONCLUSION

Single-lumen stereolithography-manufactured PEG nerve conduits promote nerve regeneration, with regenerating axon numbers approaching that of normal nerve. Multi-lumen conduits demonstrated significantly less nerve regeneration, possibly due to physical properties of the conduit inhibiting growth. Further studies are necessary to compare the efficacy of the two conduits for functional recovery and to elucidate the reasons underlying their differences in nerve regeneration potential.

Maternal obesity and gestational weight gain

The aim of the study was to analyse gestational weight gain (GWG) according to body mass index (BMI) category and to explore the relationship between GWG and pregnancy complications. Women were recruited in the 1st trimester. Weight and height were measured and BMI calculated. Weight was measured at 38 weeks' gestation and GWG calculated. Clinical details were obtained prospectively. Of the 604 women recruited, 45.5% were primigravidas and 25.2% were obese. The overall mean GWG was 11.6 kg (SD 6.0). In obese women, the mean GWG was 10.4 kg (SD 7.5) compared with 12.6 kg (SD 5.7) in the normal BMI category (p < 0.001). Maternal obesity but not increased GWG was associated with an increased risk of induction of labour, caesarean section and pre-eclampsia. It was concluded that obese women were more likely to exceed GWG recommendations, despite lower GWG than non-obese women. Maternal obesity and not GWG increased the risk of pregnancy complications.

Extracranial Internal Carotid Artery Mycotic Aneurysm: Case Report and Review

Mycotic aneurysms of the internal carotid artery (ICA) are rare and often difficult to diagnose. They can have nonspecific signs and symptoms, an unclear etiology, and can lead to severe morbidity and mortality if left untreated. We present a case of a 47-year-old woman with an apparent mycotic aneurysm of the extracranial ICA associated with Klebsiella pneumonia. We discuss the various clinical findings and radiographic imaging that lead to this unusual diagnosis and the details of our surgical treatment, which included excision of the mycotic aneurysm and reconstruction with a greater saphenous vein interposition graft. We also review the literature on mycotic aneurysms of the ICA, including the radiologic modalities available to diagnose this condition, epidemiology, pathophysiology, and treatment options.

Rescuing the emergency--multiple expertise and IT in the emergency field

OBJECTIVES

The rapid growth, both in technical and social approaches to the innovation phenomenon in health care suggests that profound changes are occurring. The focus of the project was to evaluate these changes through the case study of the French emergency field.

METHODS

The consequences of information technology implementations in the Emergency Services are presented as models to investigate the importance of technical expertise, with both the involvement of all the stakeholders from the beginning of the design and the test of the new tool in real settings.

RESULTS AND CONCLUSION

A new form of work resulted for the management of the crisis, which questioned the status of the actors and their actions, and the characteristics of the protocols of rescue. The outcome of this project was a new model built for the rescue of the emergency field which encompasses alternative forms of expertise.