Percutaneous management of thoracolumbar burst fractures: Evolution of techniques and strategy

SummaryIntroductionA number of techniques have been described in the management of thoracolumbar spinal fractures, testimony to the absence of consensus on their treatment. For the past few years, minimally invasive techniques have been developed to limit surgery-related iatrogenic injury. The objective of this study was to report the results of percutaneous management of these lesions and the technical progress made based on our experience.Patients and methodsTwenty-nine patients presenting an A3 fracture, with a mean age of 51 years, were included in this study. All had a balloon kyphoplasty and percutaneous osteosynthesis. Of the first 22 cases, kyphoplasty was the initial procedure performed associated with reduction maneuvers using distraction. Assessment was clinical (neurological status and pain intensity) and radiological (implant positioning, cement leakage, restoration of local kyphosis and any loss of correction).ResultsIn the overall series, the mean local kyphosis correction was 11° with a 2° angle loss at the last follow-up. Pain assessment showed significant improvement, decreasing from 6/10 to 1/10 on discharge. The mean hospital stay lasted 4 days. On the follow-up radiological exams, no cases of extrapedicular screw migration were noted; in two cases, lateral cement leakage was found. The results were equivalent in terms of correction no matter which procedure was performed first, although for the second part of the series the technology was available to bend the spinal fixation rod to the desired curve.DiscussionThe results of this study support the growing interest in minimally invasive techniques in the management of spinal injuries with no neurological deficit. In addition, the evolving material makes it possible to come close to conventional techniques, including reduction maneuvers, while limiting muscle injury by using a purely percutaneous approach. Rigorous patient selection is necessary and the time to learn the procedure must be taken into account. Studies with a longer follow-up are required to confirm the stability of the correction over time.Level of evidenceLevel IV. Retrospective observational study

Cancer evolution: mathematical models and computational inference.

Cancer is a somatic evolutionary process characterized by the accumulation of mutations, which contribute to tumor growth, clinical progression, immune escape, and drug resistance development. Evolutionary theory can be used to analyze the dynamics of tumor cell populations and to make inference about the evolutionary history of a tumor from molecular data. We review recent approaches to modeling the evolution of cancer, including population dynamics models of tumor initiation and progression, phylogenetic methods to model the evolutionary relationship between tumor subclones, and probabilistic graphical models to describe dependencies among mutations. Evolutionary modeling helps to understand how tumors arise and will also play an increasingly important prognostic role in predicting disease progression and the outcome of medical interventions, such as targeted therapy.FM would like to acknowledge the support of The University of Cambridge, Cancer Research UK and Hutchison Whampoa Limited.This is the final published version. It first appeared at http://sysbio.oxfordjournals.org/content/early/2014/10/07/sysbio.syu081.short?rss=1

Unc13A and Unc13B contribute to the decoding of distinct sensory information in Drosophila

The physical distance between presynaptic Ca2+ channels and the Ca2+ sensors triggering the release of neurotransmitter-containing vesicles regulates short-term plasticity (STP). While STP is highly diversified across synapse types, the computational and behavioral relevance of this diversity remains unclear. In the Drosophila brain, at nanoscale level, we can distinguish distinct coupling distances between Ca2+ channels and the (m)unc13 family priming factors, Unc13A and Unc13B. Importantly, coupling distance defines release components with distinct STP characteristics. Here, we show that while Unc13A and Unc13B both contribute to synaptic signalling, they play distinct roles in neural decoding of olfactory information at excitatory projection neuron (ePN) output synapses. Unc13A clusters closer to Ca2+ channels than Unc13B, specifically promoting fast phasic signal transfer. Reduction of Unc13A in ePNs attenuates responses to both aversive and appetitive stimuli, while reduction of Unc13B provokes a general shift towards appetitive values. Collectively, we provide direct genetic evidence that release components of distinct nanoscopic coupling distances differentially control STP to play distinct roles in neural decoding of sensory information

Confirmation of a recent bipolar ejection in the very young hierarchical multiple system IRAS 16293-2422

We present and analyze two new high-resolution (approx 0.3 arcsec), high-sensitivity (approx 50 uJy beam-1) Very Large Array 3.6 cm observations of IRAS 16293-2422 obtained in 2007 August and 2008 December. The components A2alpha and A2beta recently detected in this system are still present, and have moved roughly symmetrically away from source A2 at a projected velocity of 30-80 km s-1. This confirms that A2alpha and A2beta were formed as a consequence of a very recent bipolar ejection from A2. Powerful bipolar ejections have long been known to occur in low-mass young stars, but this is -to our knowledge-- the first time that such a dramatic one is observed from its very beginning. Under the reasonable assumption that the flux detected at radio wavelengths is optically thin free-free emission, one can estimate the mass of each ejecta to be of the order of 10^-8 Msun. If the ejecta were created as a consequence of an episode of enhanced mass loss accompanied by an increase in accretion onto the protostar, then the total luminosity of IRAS 16293-2422 ought to have increased by 10-60% over the course of at least several months. Between A2alpha and A2beta, component A2 has reappeared, and the relative position angle between A2 and A1 is found to have increased significantly since 2003-2005. This strongly suggests that A1 is a protostar rather than a shock feature, and that the A1/A2 pair is a tight binary system. Including component B, IRAS 16293-2422 therefore appears to be a very young hierarchical multiple system.Comment: Accepted for publication in The Astrophysical Journa

Detection of ultra-high energy cosmic ray showers with a single-pixel fluorescence telescope

We present a concept for large-area, low-cost detection of ultra-high energy cosmic rays (UHECRs) with a Fluorescence detector Array of Single-pixel Telescopes (FAST), addressing the requirements for the next generation of UHECR experiments. In the FAST design, a large field of view is covered by a few pixels at the focal plane of a mirror or Fresnel lens. We report first results of a FAST prototype installed at the Telescope Array site, consisting of a single 200 mm photomultiplier tube at the focal plane of a 1 m$^2$ Fresnel lens system taken from the prototype of the JEM-EUSO experiment. The FAST prototype took data for 19 nights, demonstrating remarkable operational stability. We detected laser shots at distances of several kilometres as well as 16 highly significant UHECR shower candidates.Comment: Accepted for publication in Astroparticle Physic