Catheter Access Port (Computed Tomography) Myelography in Intrathecal Drug Delivery Troubleshooting: A Case Series of 70 Procedures

Objectives: Intrathecal drug delivery is used for the treatment of intractable spasticity, dystonia, and pain. When the symptomatology fails to respond to therapy, the cause could be failure of the medication infusion. The purpose of this study is to assess pump catheter access port (CAP)-myelography and CAP-CT-myelography as advanced imaging methods in treatment failure. Materials and Methods: We analyzed observational routinely collected data of 70 CAP procedures with 2D/3D reconstructions and additional imaging of 53 adult patients where the cause of treatment was unclear between November 2013 and November 2018. CAP-myelography and CAP-CT myelography were performed with postprocessing 2D/3D reconstructions. When myelography could not be obtained or when the result did not reveal the cause of the treatment failure, additional procedures, such as noncontrast CT, MRI, lumbar puncture CT, and 111Indium-DTPA SPECT-CT, were performed. Results: CAP fluid aspiration prior to contrast medium injection was not possible (N = 17). In one case, contrast was injected into the pump pocket unintentionally (N = 1). Of 70 procedures, 24% were unaspiratable. The remaining CAP myelography examinations (N = 52) had limited value for the diagnosis. CAP-CT myelography (N = 50) was normal (N = 31). The abnormal results (N = 19) were dorsal dural leak (N = 5), subdural catheter position (N = 2), limited rostral flow of contrast material (N = 4), limited and abnormal contrast distribution (N = 3), obstruction of rostral flow (N = 2), a leak at the pump-catheter connection (N = 1), and a sheared catheter localized in the pump pocket (N = 2). Limited contrast distributions were found to be false positive findings (N = 2). Four normal CT-CAP myelographic procedures were false negatives, as the reference tests revealed a cause of intrathecal drug delivery (ITDD) failure. The CAP-CT procedures resulted in a sensitivity of 81% (17/21) and a specificity of 93% (27/29). Conclusions: CAP-CT myelography with 2D/3D reconstructions is an essential step in the diagnostic algorithm for cases involving ITDD failure

Neutralino Dark Matter in BMSSM Effective Theory

We study thermal neutralino dark matter in an effective field theory extension of the MSSM, called "Beyond the MSSM" (BMSSM) in Dine, Seiberg and Thomas (2007). In this class of effective field theories, the field content of the MSSM is unchanged, but the little hierarchy problem is alleviated by allowing small corrections to the Higgs/higgsino part of the Lagrangian. We perform parameter scans and compute the dark matter relic density. The light Higgsino LSP scenario is modified the most; we find new regions of parameter space compared to the standard MSSM. This involves interesting interplay between the WMAP dark matter bounds and the LEP chargino bound. We also find some changes for gaugino LSPs, partly due to annihilation through a Higgs resonance, and partly due to coannihilation with light stops in models that are ruled in by the new effective terms.Comment: 37 pages + appendi

Movement profile influences systemic stress and biomechanical resilience to high training load exposure

Objectives: Determine the influence of movement profile on systemic stress and mechanical loading before and after high training load exposure. Design: Cross-sectional cohort study. Methods: 43 physically active, college-aged field or court sport female athletes participated in this study. Participants were assigned to a “excellent” (n = 22; age = 20.5 ± 1.9 yrs, height = 1.67 ± 0.67 m, mass = 64.5 ± 7.8 kg) or “poor” (n = 21; age = 20.4 ± 1.3 yrs, height = 1.69 ± 0.67 m, mass = 60.9 ± 6.1 kg) movement group defined by The Landing Error Scoring System. Participants completed five cycles of high training load exercise of 5-min treadmill-running at a speed coincident with 100–120% ventilatory threshold and 10 jump-landings from a 30-cm box. Jump-landing vertical ground reaction force and serum cortisol were evaluated prior to and following exercise. Vertical ground reaction force ensemble averages and 95% confidence interval waveforms were generated for pre-exercise, post-exercise, and pre-post exercise changes. A two-way mixed model ANOVA was used to evaluate the effect of movement profile on systemic stress before and after exercise. Results: There was no significant difference in changes in serum cortisol between the poor and excellent groups (p = 0.69) in response to exercise. Overall, individuals in the poor group exhibited a higher serum cortisol level (p < 0.05, d = 0.85 [0.19,1.48]). The poor group exhibited higher magnitude vertical ground reaction force prior to (d = 1.02–1.26) and after exercise (d = 1.15) during a majority of the stance phase. Conclusions: Individuals with poor movement profiles experience greater mechanical loads compared to individuals with excellent movement profiles. A poor movement profile is associated with greater overall concentrations of circulating cortisol, representative of greater systemic stress

A new view of the 0- and 2+ glueballs

Data on $J/\Psi \to \gamma (\rho\rho)$ demand a broad $0^-$ $\rho\rho$ signal, attributable to a glueball with a mass of 1750--2100 MeV. Decays of this broad state to $\rho\rho$, $\omega\omega$, $K^*\bar K^*$ and $\phi \phi$ channels agree well with flavour blindness. The narrow $\iota(1440)$ may be attributed to mixing between the glueball and the $s\bar s$ radial excitation. The latter is pushed down in mass by repulsion between the two levels. We conjecture that the $2^+$ glueball may likewise be broad. Mixing between it and the $2^3P_2~q\bar q$ and $s\bar s$ radial excitation can explain the appearance of $f_2(1565)$ and a $2^+$ $\Theta (1710)$ at masses lower than anticipated. Mixing with higher $q\bar q$ states can explain the $2^+$ resonance at 1920 MeV and also $\phi \phi$ signals observed by Etkin et al. and by the JETSET collaboration.Comment: 15 pages + 3 postscript figure

The Influence of the Degree of Heterogeneity on the Elastic Properties of Random Sphere Packings

The macroscopic mechanical properties of colloidal particle gels strongly depend on the local arrangement of the powder particles. Experiments have shown that more heterogeneous microstructures exhibit up to one order of magnitude higher elastic properties than their more homogeneous counterparts at equal volume fraction. In this paper, packings of spherical particles are used as model structures to computationally investigate the elastic properties of coagulated particle gels as a function of their degree of heterogeneity. The discrete element model comprises a linear elastic contact law, particle bonding and damping. The simulation parameters were calibrated using a homogeneous and a heterogeneous microstructure originating from earlier Brownian dynamics simulations. A systematic study of the elastic properties as a function of the degree of heterogeneity was performed using two sets of microstructures obtained from Brownian dynamics simulation and from the void expansion method. Both sets cover a broad and to a large extent overlapping range of degrees of heterogeneity. The simulations have shown that the elastic properties as a function of the degree of heterogeneity are independent of the structure generation algorithm and that the relation between the shear modulus and the degree of heterogeneity can be well described by a power law. This suggests the presence of a critical degree of heterogeneity and, therefore, a phase transition between a phase with finite and one with zero elastic properties.Comment: 8 pages, 6 figures; Granular Matter (published online: 11. February 2012

Automated quantification of the landing error scoring system with a markerless motion-Capture system

Context: The Landing Error Scoring System (LESS) can be used to identify individuals with an elevated risk of lower extremity injury. The limitation of the LESS is that raters identify movement errors from video replay, which is time-consuming and, therefore, may limit its use by clinicians. A markerless motion-capture system may be capable of automating LESS scoring, thereby removing this obstacle. Objective: To determine the reliability of an automated markerless motion-capture system for scoring the LESS. Design: Cross-sectional study. Setting: United States Military Academy. Patients or Other Participants: A total of 57 healthy, physically active individuals (47 men, 10 women; age ¼ 18.6 6 0.6 years, height ¼ 174.5 6 6.7 cm, mass ¼ 75.9 6 9.2 kg). Main Outcome Measure(s): Participants completed 3 jump-landing trials that were recorded by standard video cameras and a depth camera. Their movement quality was evaluated by expert LESS raters (standard video recording) using the LESS rubric and by software that automates LESS scoring (depth-camera data). We recorded an error for a LESS item if it was present on at least 2 of 3 jump-landing trials. We calculated j statistics, prevalence- and bias-adjusted j (PABAK) statistics, and percentage agreement for each LESS item. Interrater reliability was evaluated between the 2 expert rater scores and between a consensus expert score and the markerless motion-capture system score. Results: We observed reliability between the 2 expert LESS raters (average j ¼ 0.45 6 0.35, average PABAK ¼ 0.67 6 0.34; percentage agreement ¼ 0.83 6 0.17). The markerless motion-capture system had similar reliability with consensus expert scores (average j ¼ 0.48 6 0.40, average PABAK ¼ 0.71 6 0.27; percentage agreement ¼ 0.85 6 0.14). However, reliability was poor for 5 LESS items in both LESS score comparisons. Conclusions: A markerless motion-capture system had the same level of reliability as expert LESS raters, suggesting that an automated system can accurately assess movement. Therefore, clinicians can use the markerless motion-capture system to reliably score the LESS without being limited by the time requirements of manual LESS scoring

Plain radiography in patients treated with intrathecal drug delivery using an implantable pump device

Objectives: Intrathecal drug administration using an implanted pump system is well established in intractable spasticity and pain. However, despite continuous advancements in manufacturing technology, adverse events related to the pump and catheter still occur. Most of them, such as migration, damage, disconnection and occlusion, are related to the spinal catheter. The aim of this overview is to update radiologists on how plain radiography of the implanted delivery system for intrathecal drug administration should be interpreted and to increase awareness for the need of urgent and timely multidisciplinary troubleshooting. Methods: Plain radiographic images of patients treated with intrathecal drug administration using an implantable drug delivery system were analysed in a multidisciplinary setting at our (university) referral centre for complications in intrathecal drug administration. Results: Examples of catheter-related adverse events are described and a proposal is made for stepwise interpretation of standard plain radiographic images. Conclusions: Plain radiological images are the mainstay for the diagnosis of catheter-related adverse events in intrathecal drug delivery. Radiologists play an important role in an early diagnosis. An awareness of abnormal radiological findings seems important to avoid a life-threatening withdrawal syndrome. Teaching points: • Untimely cessation of intrathecal drug delivery can lead to a life-threatening withdrawal syndrome. • Initially mild symptoms can lead to an exacerbation of a withdrawal syndrome. • Most intrathecal catheter-related problems are visible on plain radiography. • Common causes of catheter problems are migration, lacerations, occlusion and disconnection. • Knowledge on implanted intrathecal catheters is crucial for interpretation of plain radiography

An epitaxial model for heterogeneous nucleation on potent substrates

© The Minerals, Metals & Materials Society and ASM International 2012In this article, we present an epitaxial model for heterogeneous nucleation on potent substrates. It is proposed that heterogeneous nucleation of the solid phase (S) on a potent substrate (N) occurs by epitaxial growth of a pseudomorphic solid (PS) layer on the substrate surface under a critical undercooling (ΔT ). The PS layer with a coherent PS/N interface mimics the atomic arrangement of the substrate, giving rise to a linear increase of misfit strain energy with layer thickness. At a critical thickness (h ), elastic strain energy reaches a critical level, at which point, misfit dislocations are created to release the elastic strain energy in the PS layer. This converts the strained PS layer to a strainless solid (S), and changes the initial coherent PS/N interface into a semicoherent S/N interface. Beyond this critical thickness, further growth will be strainless, and solidification enters the growth stage. It is shown analytically that the lattice misfit (f) between the solid and the substrate has a strong influence on both h and ΔT ; h decreases; and ΔT increases with increasing lattice misfit. This epitaxial nucleation model will be used to explain qualitatively the generally accepted experimental findings on grain refinement in the literature and to analyze the general approaches to effective grain refinement.EPSRC Centre for Innovative Manufacturing in Liquid Metal Engineerin