Biomechanical analysis of the cervical spine segment as a method for studying the functional and dynamic anatomy of the human neck.

BACKGROUND: Traditionally, dynamic and functional anatomy, in particular the dynamic anatomy of the neck, is studied on cadaveric material. However, the development of in vivo visualization technologies and in silico modeling has made it possible to expand these possibilities. Despite significant progress in the study of dynamic and functional anatomy of the neck by means of in silico methods, the issues of validating the developed models and taking into account the pronounced nonlinearity of soft tissues as well as local anisotropy remain open. The aim of this study was to develop a virtual dynamic anatomical model of the human neck and reproduce the dynamic processes in the cervical spine from this model using the finite element method. MATERIALS AND METHODS: Reverse engineering was used to generate a dynamic anatomical model of the neck from CT data (both male, 24 and 22 years old). Two segments of the cervical spine (C3-C5, C2-T1) were isolated from the resulting model for finite element analysis. Finite element mesh generation and contact interactions were performed using the HyperMesh software (Altair Engineering Inc, Troy, Michigan, USA). The anisotropic hyperelastic Holzapfel-Gasser-Ogden model was used to describe the material behavior of the fibrous rings of the disc. Material modeling and finite element analysis were performed using Abaqus CAE 6.14 software (Simulia, Johnston, Rhode Island, USA). RESULTS: A technique for creating a virtual dynamic anatomical model of the neck was elaborated and implemented. The model includes 79 major anatomical structures of the neck segmented from radiological data. A finite element analysis of the cervical spine was performed. The results of finite element analysis of the C3-C5 segment under axial load were compared with in vitro data. The proposed model shows nonlinear deformation of the disc under static loading; the model predicted displacement values agree well with the experimental ones. The displacement of the С3-С5 central vertebra with an axial load of 800 N reaches a value of 0.65 mm. For the segment C2-T1, data on intradiscal pressure, stress plots and displacements during flexion were obtained. The maximum stress value of 10.036 MPa is observed in the C3-C4 disc. CONCLUSION: Simulation results using the proposed methodology are in good agreement with experimental data. The generated biomechanical models allow describing dynamic phenomena in the cervical spine and obtaining a wide range of quantitative properties of anatomical objects, which are otherwise inaccessible to classical methods for studying dynamic and functional anatomy.

[Comparative characteristic of clinical efficacy of the original drug Movalis and its generic Amelotex in the treatment of non-specific lumbar pain]. / Sravnitel'naya kharakteristika klinicheskoi effektivnosti original'nogo preparata Movalis i Ameloteksa v lechenii nespetsificheskoi poyasnichnoi boli.

OBJECTIVE: To perform a comparative analysis of the efficacy of the original drug meloxicam (movalis) and its generic (amelotex) in the treatment of patients with lower back pain. MATERIALS AND METHODS: The analysis of treatment results of 112 (61 men and 51 women) employees of JSC «Admiralteyskie Verfi¼, aged 18 to 60 years, was carried out. All these patients were treated in the period from 2015 to 2017 at the Medical Center of JSC «Admiralteyskie Verfi¼ due to dorsalgia of lumbosacral localization (ICD-10, item M54). The average age of the patients was 42,6±10,4 (from 22 to 59 years). Age range of patients was 20-35 years (n=34); 36-50 years (n=49); >50 years (n=29). RESULTS: Compared to amelotex, movalis was more effective for the duration of pain intensity reduction (5±1,4 days (min 3, max 9) in the movalis group and 7,37±1,68 days (min 3, max 10) in the amelotex group) as well as for the total duration of temporary disability (labor losses 6,43±1,4 days (min 4, max 10) and 8,61±1,59 days (min 5, max 12), respectively). In addition, patients receiving movalis showed a more significant improvement in the Clinical Global Impression (CGI) score in all age groups compared with patients in the amelotex group. CONCLUSION: The lack of therapeutic equivalence between movalis and amelotex determines the relevance of the drug choice for complex therapy of these patients, which will improve the prognosis of the disease and the quality of life of the patient.

[Cholinergic profile as a target of rational therapy of central nervous system diseases and injuries]. / Kholinergicheskii profil' kak mishen' ratsional'noi terapii zabolevanii i travm tsentral'noi nervnoi sistemy.

AIM: A comparative analysis of the clinical efficacy of cholinergic drugs and acetylcholinesterase inhibitors (IHE), as well as their combination, in the treatment of cerebrovascular disease and consequences of intracranial injury according to clinical, instrumental and laboratory dynamic observations. MATERIAL AND METHODS: Ninety patients with cerebrovascular pathology, including 45 with chronic brain ischemia stage 2 (ICD-10 I67) and 45 with sequelae of intracranial injury (ICD-10 T90.5), were enrolled in the study. Complex treatment of patients included basic and specific therapy. The groups were divided into 3 subgroups of 15 people: the neuromidin group, the gliatilin group and the neuromidin + gliatilin group. The duration of treatment was 2 months. All patients underwent a comprehensive clinical, neurophysiological and laboratory examination prior to therapy, after 1 month and 2 month from the beginning of therapy: a study of cholinesterase activity in the blood, testing on MMSE and Hamilton scales, transcranial magnetic stimulation with determination of Central motor conduction time and somatosensory evoked potentials with calculation of Central afferent conduction time. RESULTS: Prior to treatment, a significant positive strong correlation was found between the age of patients and the level of CE activity in serum (Rs=0.77; p=0.0001). The treatment resulted in a significant (p<0.05) improvement of all parameters (except for MMSE that showed a trend towards improvement) in the neuromidin and the neuromidin + gliatilin subgroups of each group compared to those in the gliatilin subgroups. In addition, after 2 months from the beginning of treatment, there was a significant decrease in the activity of CE in serum in the neuromidin and the neuromidin + gliatilin subgroups. CONCLUSION: The study of deviations of the 'cholinergic profile' (the level of CE activity in the blood) in patients with cerebral pathology and the strategy using cholinergic drugs, IHE and their combination for the treatment of neuropsychiatric disorders, is one of the important directions in the optimization of combined therapy of patients of this profile.

Flame propagation in two-dimensional solids: Particle-resolved studies with complex plasmas.

Using two-dimensional (2D) complex plasmas as an experimental model system, particle-resolved studies of flame propagation in classical 2D solids are carried out. Combining experiments, theory, and molecular dynamics simulations, we demonstrate that the mode-coupling instability operating in 2D complex plasmas reveals all essential features of combustion, such as an activated heat release, two-zone structure of the self-similar temperature profile ("flame front"), as well as thermal expansion of the medium and temperature saturation behind the front. The presented results are of relevance for various fields ranging from combustion and thermochemistry, to chemical physics and synthesis of materials.