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.

[The minimally invasive surgical access to the thyroid and parathyroid glands through the oral cavitiy].

The use of minimally invasive surgical access and technologies allows the substantial improvement in rates of the postoperative rehabilitation, shorten the hospital stay and improve the cosmtic result of the operation. The thorough topographic description of the transoral access to the thyroid and parathyroid glands is highlighted in the article. The construction of the original wound expander is depicted. The operative technique of the hemythyroidectomy is expamled.

Bone marrow stem cells repopulate thyroid in X-ray regeneration in mice.

The aim of this study was to clarify the regeneration mechanisms of thyroid in post-irradiated C57Bl/6 mice chimeric with transgenic green fluorescent protein (GFP) positive C57Bl/6 mice after 5 and 7.5Gy X-ray exposures with the aid of morphological and immunocytochemical research of GFP-positive cell distribution. Cryostat slides of larynxes with thyroid glands were fixed by mixture of cold methanol and ethanol, cell nuclei were stained with propidium iodide. After immunocytochemical staining the slides of larynx with thyroid gland were investigated by means of confocal LSM 5 PASCAL microscope. True GFP nature of green signals in tissue slides was confirmed via additional treatment by anti-GFP antibody and Texas Red labeled second antibody. Separate GFP-positive cells were observed in the walls of follicles and between follicles of chimeric mice 9-10 months after X-ray exposure. GFP signal was viewed as cytoplasmic droplets and within the colloid of follicles. The share of GFP-positive follicles reached 6.1±1.8%. There was also co-localization of GFP signals and positive staining for thyroglobulin by monoclonal antibody. As many as 20.8±1.8% among all propidium iodide positive blood cells and 52.3±8.3% among propidium iodide positive bone marrow cells were at the same time GFP-positive. In conclusion, the results show that the bone marrow stem cells participate in the thyroid gland regeneration after 5Gy X-ray exposure.

[Minimally invasive surgical methods in treatment of nodular goiter].

The article presents results of topographo-anatomical investigation of the asymmetric mini-access used in surgical treatment of the nodular goiter. It was established that the mini-access is rational, adequate and does not require special surgical instruments. The performance of hemithyroidectomy from the asymmetric mini-access used in 99 patients with nodular goiter had excellent cosmetic effect, early rehabilitation and low number of complications. Long-term results of treatment by the method of ethanol destruction were investigated in 50 patients. At the end of the observation the diameter of the nodes was found to increase as compared with the minimal indices.

[Hyperglycemic syndrome at the early postoperative period].

An analysis of treatment of 141 patients with hyperglycemic syndrome at the early postoperative period was made, which was 1.3% of all the patients operated on during this period. Inflammatory postoperative complications took place in 30 (21.3%) patients in the group of patients with hyperglycemic syndrome. It suggests that hyperglycemia at the early postoperative period should be considered not simply as criterion of a severe state, but also as a factor having a direct influence on the course of the pathological process. So, these patients should be given sugar-decreasing therapy with monitoring of the glucose level.

[Surgical strategy for wounds of the cervical part of the esophagus]. / Khirurgicheskaia taktika pri raneniiakh sheinogo otdela pishchevoda.

An analysis of results of treatment of 425 patients aged from 15 to 85 years with penetrating wounds of the neck was made. In 40 (8.1%) patients there were wounds of the cervical part of the esophagus, 29 of them had associated injuries. The proposed active surgical strategy consisted in a necessary thorough revision of the penetrating wounds of the neck using general anesthesia and then directly in the operation room using subsidiary methods of examination such as urgent x-ray analysis with a water-soluble contrast, esophagoscopy, larengotracheoscopy. This approach allowed detection of injuries of the cervical part of the esophagus, even in cases of the absence of clinical symptoms of esophagus injuries. In all the patients the wounds of the esophagus were sutured and followed by active aspiration drainage and antibacterial treatment with modern antimicrobial medicines.

[The diagnosis and treatment of injuries of the upper respiratory tract in wounds and traumas of the neck]. / Diagnostika i lechenie povrezhdenii verkhnikh dykhatel'nykh putei pri raneniiakh i travmakh shei.

The authors made an analysis of results of treatment of 339 patients with wounds and closed injuries of the neck. Laryngotracheal injuries were found in 27 (7.9%) patients, in 15 patients the injuries being of combined character. Active surgical strategy including the necessary thorough revision of the penetrating wounds of the neck during operation under general narcosis anesthesia, by instrumental methods of examination. Such strategy allowed timely detection and adequate elimination of injuries of the organs and vessels of the neck and improvement of the results of treatment of such patients.

[A comparative evaluation of methods for vena cava filtration in venous thromboembolisms]. / Sravnitel'naia otsenka metodov kavafil'tratsii pri émbologennykh flebotrombozakh.

The article presents an experience with the work of a city phlebologic center, confirming the importance of active introduction of modern surgical methods of prevention of embolism of the pulmonary artery in the program of aid to patients with acute embologenic iliofemoral phlebothromboses. Use of the methods of endo- and exovenous cava filtration and cavaplication allowed lethality in this group of patients to be reduced from 15-20% to 1%.