Introduction
With the advances and improvement of computer-assisted surgery devices, computer-guided pedicle screws insertion has been applied to the lumbar, thoracic and cervical spine. The purpose ...of the present study was to perform a systematic review of all available prospective evidence regarding pedicle screw insertion techniques in the thoracic and lumbar human spine.
Materials and methods
We considered all prospective in vivo clinical studies in the English literature that assessed the results of different pedicle screw placement techniques (free-hand technique, fluoroscopy guided, computed tomography (CT)-based navigation, fluoro-based navigation). MEDLINE, OVID, and Springer databases were used for the literature search covering the period from January 1950 until May 2010.
Results
26 prospective clinical studies were eventually included in the analysis. These studies included in total 1,105 patients in which 6,617 screws were inserted. In the studies using free-hand technique, the percentage of the screws fully contained in the pedicle ranged from 69 to 94%, with the aid of fluoroscopy from 28 to 85%, using CT navigation from 89 to 100% and using fluoroscopy-based navigation from 81 to 92%. The screws positioned with free-hand technique tended to perforate the cortex medially, whereas the screws placed with CT navigation guidance seemed to perforate more often laterally.
Conclusions
In conclusion, navigation does indeed exhibit higher accuracy and increased safety in pedicle screw placement than free-hand technique and use of fluoroscopy.
Abstract
The study of linear time invariant descriptor systems has intimately been related to the study of matrix pencils. It is true that a large number of systems can be reduced to the study of ...differential (or difference) systems, $S\left ( {F,G} \right )$, $$\begin{align*} & S\left({F,G}\right): F\dot{x}(t) = G{x}(t) \left(\text{or the dual, } F{x}(t) = G\dot{x}(t)\right), \end{align*}$$and $$\begin{align*} & S\left({F,G}\right): Fx_{k+1} = Gx_k \left(\text{or the dual, } Fx_k=Gx_{k+1}\right)\!, F,G \in{\mathbb{C}^{m \times n}}, \end{align*}$$and their properties can be characterized by homogeneous matrix pencils, $sF - \hat{s}G$. Based on the fact that the study of the invariants for the projective equivalence class can be reduced to the study of the invariants of the matrices of set ${\mathbb{C}^{k \times 2}}$ (for $k \geqslant 3$ with all $2\times 2$-minors non-zero) under the extended Hermite equivalence, in the context of the bilinear strict equivalence relation, a novel projective transformation is analytically derived.
Abstract
Background
Clarithromycin may act as immune-regulating treatment in sepsis and acute respiratory dysfunction syndrome. However, clinical evidence remains inconclusive. We aimed to evaluate ...whether clarithromycin improves 28-day mortality among patients with sepsis, respiratory and multiple organ dysfunction syndrome.
Methods
We conducted a multicenter, randomized, clinical trial in patients with sepsis. Participants with ratio of partial oxygen pressure to fraction of inspired oxygen less than 200 and more than 3 SOFA points from systems other than the respiratory function were enrolled between December 2017 and September 2019. Patients were randomized to receive 1 gr of clarithromycin or placebo intravenously once daily for 4 consecutive days. The primary endpoint was 28-day all-cause mortality. Secondary outcomes were 90-day mortality; sepsis response (defined as at least 25% decrease in SOFA score by day 7); sepsis recurrence; and differences in peripheral blood cell populations and leukocyte transcriptomics.
Results
Fifty-five patients were allocated to each arm. By day 28, 27 (49.1%) patients in the clarithromycin and 25 (45.5%) in the placebo group died (risk difference 3.6% 95% confidence interval (CI) − 15.7 to 22.7;
P
= 0.703, adjusted OR 1.03 95%CI 0.35–3.06;
P
= 0.959). There were no statistical differences in 90-day mortality and sepsis response. Clarithromycin was associated with lower incidence of sepsis recurrence (OR 0.21 95%CI 0.06–0.68;
P
= 0.012); significant increase in monocyte HLA-DR expression; expansion of non-classical monocytes; and upregulation of genes involved in cholesterol homeostasis. Serious and non-serious adverse events were equally distributed.
Conclusions
Clarithromycin did not reduce mortality among patients with sepsis with respiratory and multiple organ dysfunction. Clarithromycin was associated with lower sepsis recurrence, possibly through a mechanism of immune restoration.
Clinical trial registration
clinicaltrials.gov identifier
NCT03345992
registered 17 November 2017; EudraCT 2017-001056-55.
Hydrogen sulfide (H2S) has recently been recognized as a novel gaseous transmitter with several anti-inflammatory properties. The role of host- derived H2S in infections by Pseudomonas aeruginosa was ...investigated in clinical and mouse models. H2S concentrations and survival was assessed in septic patients with lung infection. Animal experiments using a model of severe systemic multidrug-resistant P. aeruginosa infection were performed using mice with a constitutive knock-out of cystathionine-γ lyase (Cse) gene (Cse-/-) and wild-type mice with a physiological expression (Cse+/+). Experiments were repeated in mice after a) treatment with cyclophosphamide; b) bone marrow transplantation (BMT) from a Cse+/+ donor; c) treatment with H2S synthesis inhibitor aminooxyacetic acid (ΑΟΑΑ) or propargylglycine (PAG) and d) H2S donor sodium thiosulfate (STS) or GYY3147. Bacterial loads and myeloperoxidase activity were measured in tissue samples. The expression of quorum sensing genes (QS) was determined in vivo and in vitro. Cytokine concentration was measured in serum and incubated splenocytes. Patients survivors at day 28 had significantly higher serum H2S compared to non-survivors. A cut- off point of 5.3 μΜ discriminated survivors with sensitivity 92.3%. Mortality after 28 days was 30.9% and 93.7% in patients with H2S higher and less than 5.3 μΜ (p = 7 x 10-6). In mice expression of Cse and application of STS afforded protection against infection with multidrug-resistant P. aeruginosa. Cyclophosphamide pretreatment eliminated the survival benefit of Cse+/+ mice, whereas BMT increased the survival of Cse-/- mice. Cse-/- mice had increased pathogen loads compared to Cse+/+ mice. Phagocytic activity of leukocytes from Cse-/- mice was reduced but was restored after H2S supplementation. An H2S dependent down- regulation of quorum sensing genes of P.aeruginosa could be demonstrated in vivo and in vitro. Endogenous H2S is a potential independent parameter correlating with the outcome of P. aeruginosa. H2S provides resistance to infection by MDR bacterial pathogens.
In the literature of control and system theory, several explicit formulae appeared for solving square Vandermonde systems and computing the inverse of it. In the present paper, we will discuss and ...present analytically the generalized inverses of the rectangular and square Vandermonde matrix. These matrices have been appeared recently in an interesting control and system theory problem, where the change of the initial state of a linear descriptor system in (almost) zero time is required.
Non-alcoholic fatty liver disease (NAFLD) is a multifactorial, wide-spectrum liver disorder. Small intestinal bacterial overgrowth (SIBO) is characterized by an increase in the number and/or type of ...colonic bacteria in the upper gastrointestinal tract. SIBO, through energy salvage and induction of inflammation, may be a pathophysiological factor for NAFLD development and progression.
Consecutive patients with histological, biochemical, or radiological diagnosis of any stage of NAFLD (non-alcoholic fatty liver NAFL, non-alcoholic steatohepatitis NASH, cirrhosis) underwent upper gastrointestinal endoscopy. Duodenal fluid (2cc) was aspirated from the 3rd-4th part of duodenum into sterile containers. SIBO was defined as ≥10
aerobic colony-forming units (CFU)/mL of duodenal aspirate and/or the presence of colonic-type bacteria. Patients without any liver disease undergoing gastroscopy due to gastroesophageal reflux disease (GERD) comprised the healthy control (HC) group. Concentrations (pg/mL) of tumor necrosis factor alpha (TNFα), interleukin (IL)-1β, and IL-6 were also measured in the duodenal fluid. The primary endpoint was to evaluate the prevalence of SIBO in NAFLD patients, while the comparison of SIBO prevalence among NAFLD patients and healthy controls was a secondary endpoint.
We enrolled 125 patients (51 NAFL, 27 NASH, 17 cirrhosis, and 30 HC) aged 54 ± 11.9 years and with a weight of 88.3 ± 19.6 kg (NAFLD vs. HC 90.7 ± 19.1 vs. 80.8 ± 19.6 kg,
= 0.02). Overall, SIBO was diagnosed in 23/125 (18.4%) patients, with Gram-negative bacteria being the predominant species (19/23; 82.6%). SIBO prevalence was higher in the NAFLD cohort compared to HC (22/95; 23.2% vs. 1/30; 3.3%,
= 0.014). Patients with NASH had higher SIBO prevalence (6/27; 22.2%) compared to NAFL individuals (8/51; 15.7%), but this difference did not reach statistical significance (
= 0.11). Patients with NASH-associated cirrhosis had a higher SIBO prevalence compared to patients with NAFL (8/17; 47.1% vs. 8/51; 15.7%,
= 0.02), while SIBO prevalence between patients with NASH-associated cirrhosis and NASH was not statistically different (8/17; 47.1% vs. 6/27; 22.2%,
= 0.11). Mean concentration of TNF-α, IL-1β, and IL-6 did not differ among the different groups.
The prevalence of SIBO is significantly higher in a cohort of patients with NAFLD compared to healthy controls. Moreover, SIBO is more prevalent in patients with NASH-associated cirrhosis compared to patients with NAFL.
In the literature regarding linear systems and mathematical control theory, several different techniques have been developed for obtaining the solution of homogeneous linear time-invariant (LTI) ...descriptor differential systems. In this article, applying the complex Weierstrass canonical form, we investigate the conditions under which a descriptor system with a specific structure and desired properties is being constructed using perturbation theory. Our approach is very general, and as an example, a stable homogeneous LTI descriptor system is designed. Thus, a proportional and derivative controller can be used, such as the case where a family of perturbed pencils is defined and the solutions of the initial and the relative perturbed systems are
-close with respect to a Frobenius distance. A Step-algorithm and an illustrative example are also presented to illustrate the results of this article.
In this brief paper, a new sharper upper bound for the error ‖
x
(
kT
) −
x
k
‖ that derives from the procedure of discretization of the solution of a Linear descriptor (regular) differential input ...system with consistent initial conditions, and Time-Invariant coefficients (LTI) is calculated and fully discussed. Practically speaking, considering numerous applications in engineering (especially in robotics and digital control) and computer science, we are very interested in determining such kind of upper bounds, since they are significant in the design process of the sampling period
T
.
Abstract Background context Traumatic pneumorrhachis (PR) is a rare entity, consisting of air within the spinal canal. It can be classified as epidural or subarachnoid, identifying the anatomical ...space where the air is located, and is associated with different etiologies, pathology, and treatments. Purpose To conduct a systematic review of the scientific literature focused on the etiology, pathomechanism, diagnosis, and treatment of PR, and to report a case of an asymptomatic epidural type. Study design International medical literature has been reviewed systematically for the term “traumatic pneumorrhachis” and appropriate related subject headings, such as traumatic intraspinal air, traumatic intraspinal pneumocele, traumatic spinal pneumatosis, traumatic spinal emphysema, traumatic aerorachia, traumatic pneumosaccus, and traumatic air myelogram. All cases that were identified were evaluated concerning their etiology, pathomechanism, and possible complications. Samples Studies that included one of the aforementioned terms in their titles. Methods A systematic review was performed to identify, evaluate, and summarize the literature related to the term “traumatic pneumorrhachis” and related headings. Furthermore, we report a rare case of an asymptomatic epidural PR extending to the cervical and thoracic spinal canal. We present the current data regarding the etiology, pathomechanism, diagnosis, and treatment modalities of patients with PR. Results The literature review included 37 related articles that reported 44 cases of traumatic PR. Only isolated case reports and series of no more than three cases were found. In 21 cases, the air was located in the epidural space, and in 23 cases, it was in the subarachnoid space. Most of the cases were localized to a specific spinal region. However, eight cases extending to more than one spinal region have been reported. Conclusions Traumatic PR is an asymptomatic rare clinical entity and often is underdiagnosed. It usually resolves by itself without specific treatment. We stress the significance of this information to trauma specialists, so that they may better differentiate between epidural and subarachnoid PR. This is of great significance because subarachnoid PR is a marker of severe injury. The management of traumatic PR has to be individualized and frequently requires multidisciplinary treatment, involving head, chest, and/or abdomen intervention.
In the literature, the dual matrix pencils sF-G and F-sˆG are identified with the homogeneous pencil sF-sˆG. In the present paper, for a given a homogeneous pencil which is unstable, in the sense ...that it has roots in the closed right half-plane, a bilinear transformation is determined such that the new homogeneous bilinear-equivalent matrix pencil is stable. The notion of bilinear equivalence is introduced and a stabilization criterion of a homogeneous matrix pencil is finally derived.
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