Introduction. The thoracolumbar junction is one of the most frequently damaged parts of the human spine when exposed to a traumatic factor. Corpectomy in combination with posterior decompression and restoration of the spinal support function is often performed using an interbody implant and posterior transpedicular stabilization to achieve adequate decompression and stabilization in severe traumatic injuries of this level. The surgery of this type is characterized by significant instability of the operated segment and determines increased requirements for the rigidity and reliability of posterior fixation. We have modeled the situation of a two-level corpectomy with subsequent replacement of bodies with a mesh implant and posterior transpedicular stabilization with 8 screws. Objective. To study the stress-strain state of the thoracolumbar spine model after resection of the Th12-L1 vertebrae with different variants of transpedicular fixation under the influence of a compressive load. Materials and methods. A mathematical finite element model of the human thoracolumbar spine has been developed, the components of which are the Th9 ‒ Th11 and L2-L5 vertebrae (vertebrae Th12-L1 are removed), as well as elements of hardware - interbody support and transpedicular system. Four variants of transpedicular fixation were modeled: using short screws and long screws passing through the cortical layer of anterior wall of vertebral body, as well as two cross links and without them. The stress-strain state of the models was studied under the influence of a vertical compressive distributed load, which was applied to the body of the Th9 vertebra and its articular surfaces. The load value was 350 N, corresponding to the weight of the upper body. Results. d It was found that transpedicular fixation of the thoracolumbar vertebrae with the use of long screws reduces the level of tension in the bone elements of the models. In the area of screw entry into the pedicle of the T10, T11, L2 and L3 vertebral arch, the load when using short screws was 3.1, 1.7, 3.9 and 12.1 MPa, respectively, when using bicortically installed screws - 2.9, 1.8, 3.8 and 10.6 MPa. The addition of two cross-links also reduces the maximum load values in critical areas of the model to a certain extent. In case of short screws combination and two cross-links, the load in these areas was 2.8, 1.7, 3.6 and 11.5 MPa, when using bicortical screws and cross-links - 2.8, 1.6, 3.3 and 9.3 MPa. The study of the stress-strain state of other parts of the model revealed a similar trend. Conclusions. The use of long screws with fixation in the cortical bone of anterior part of the vertebral bodies reduces the level of tension in the bone elements of the models. The use of cross links provides greater rigidity to the transpedicular system, that also reduces the tension in the bone tissue.

Fractures at the thoracolumbar junction are the most common traumatic spinal injuries. Advances in instrumentation for vertebral body replacement have significantly improved surgical techniques. However, the biomechanical characteristics of stabilizing surgeries have been insufficiently studied. Objective. To investigate the stressstrain state (SSS) of a mathematical finite element model of the human thoracolumbar spine during trunk backward bending after ТhХ_ІІ vertebra resection, considering different transpedicular fixation options. Methods. A mathematical finite element model of the human thoracolumbar spine — Th_IX‒L_V vertebrae — was developed. The Тh_ХІІ vertebra was removed, and an interbody support and transpedicular system with 8 screws were implanted to simulate the postsurgical state after a Тh_ХІІ burst fracture with wide laminectomy, facetectomy, and corpectomy. The influence of transpedicular screw length and the presence of cross-links on the SSS of the model was examined. Results. The use of bicortical screws reduced stress levels in the bone elements of the model, except in the regions around the screws in the lumbar vertebrae, when compared to short screws. Installing cross-links decreased stress levels at all control points compared to models without cross-links. Specifically, in the presence of cross-links, the SSS values at the entry points of the short screws into the vertebral bodies of Th_X, Th_XI, L_I, and L_II were 2.3, 1.8, 1.2, and 5.0MPa, respectively, compared to 2.7, 2.0, 1.5, and 6.1 MPa in the models without cross-links. In the case of bicortical screws without cross-links, the stress values at the screw entry points into the pedicles of the corresponding vertebrae were 2.9, 1.5, 8.2, and 11.2 MPa, respectively, compared to 2.7, 1.5, 7.5, and 10.2 MPa in the models with cross-links. Conclusions. When the trunk is tilted backward, the use of cross-links reduces stress levels at all control points in the models, regardless of the screw length used. Bicortical transpedicular screws increase stress levels on the screws themselves and in the lumbar vertebral bodies surrounding them.

Background. Traumatic spinal injuries are a significant medical and social issue, due to both the high costs associated with initial medical care for the injured and the extensive and expensive rehabilitation required. The thoracolumbar junction (TLJ) is prone to injuries due to its biomechanical characteristics. However, the actual frequency of injuries in this area, as reported in the literature, is inconsistent. The purpose of the study was to assess the proportion of fractures at the TLJ within the overall structure of traumatic spinal injuries in the adult population. Materials and me­thods. A meta-analysis was conducted based on searches in the MEDLINE database using MeSH terms and keywords in titles and abstracts to identify studies meeting the inclusion criteria. The search identified 22 full-length articles. Data extraction and analysis were conducted by two independent experts. Results. It was found that fractures at the TLJ accoun­ted for 46.51 % (95% confidence interval (CI): 36.76–56.27 %) of the overall structure of spinal injuries, specifically fractures at level Th11 — 4.26 % (95% CI: 3.35–5.17 %), Th12 — 13.98 % (95% CI: 10.41–17.56 %), at level L1 — 22.21 % (95% CI: 17.66–26.76 %), and L2 — 9.69 % (95% CI: 6.82–12.57 %). Within the thoracolumbar division, the frequency of TLJ trauma was 61.88 % (95% CI: 52.53–71.22 %). Within the TLJ, the frequency of fractures was: vertebra Th11 — 10.2 % (95% CI: 8.05–12.36 %), Th12 — 26.56 % (95% CI: 22.42–30.7 %), vertebra L1 — 42.76 % (95% CI: 39.7–45.81 %), and L2 — 20.48 % (95% CI: 16.73–24.23 %). Conclusions. The meta-analysis provi­ded objective indicators of the frequency distribution of TLJ fractures within the overall structure of traumatic spinal injuries. To our knowledge, this is the first study to provide such detailed information through meta-analysis.

One of the priority tasks in neurosurgery is to reduce the frequency of postoperative complications and mortality. Lumbar discectomy is the most frequently performed intervention in spinal neurosurgery and it is a fairly safe procedure. One of the possible intraoperative surgical complications, that threatens the patient’s life is vascular injury. The first clinical case of damage to the large vessels during discectomy was described in 1945. It is believed that the frequency of this complication is 1‒5 cases per 10,000 surgical interventions, but the literature notes that these figures may be significantly underestimated. Some authors indicate that the frequency of this complication, despite the development of surgical techniques over the past 50 years, has not significantly decreased, so it is important for surgeons to be informed and alert about the possibility of such a problem. Among the factors that significantly increase the risk of vascular damage congenital, acquired and technical are determined. Variability of clinical symptoms of damage to lagre vessels is due to different localization of injury, type (arterial, venous or combined) and scale of vascular disaster. For each level of surgical intervention, the "most typical" vessel damage is identified. Vascular injury during discectomy can occur according to three clinical and pathomorphological scenarios: manifestation of vessel rupture symptoms, arteriovenous fistula or a pseudoaneurysm formation. According to different authors, the frequency of these findings varies significantly. This review examines the symptoms of possible variants of vascular damage development during discectomy and describes the characteristics of surgical correction methods. Along with clarifying the location and variant of vascular damage, the critical thing is assessing the amount of blood loss and the rate of ongoing bleeding. In the case of suspected massive bleeding, the paramount importance is the involvement of additional medical personnel for the surgical haemostasis and providing sufficient blood for haemotransfusions. In case of a vascular accident, the key requirement for adequate anaesthetic management is the maintenance of permissive arterial hypotension until the moment of surgical haemostasis. Targeted treatment of haemorrhagic shock in case of damage to large vessels consists of rapid haemostatic resuscitation including blood components and products in a balanced 1:1:1 ratio, such as plasma, red blood cells, fresh frozen plasma, platelets, and coagulation factors. In Ukraine, obtaining a sufficient amount of blood components and products (according to the protocol of massive haemotransfusion) in case of unpredicted blood loss is a difficult task, therefore, in the absence of certain components or blood products, whole blood can be used as an alternative. The number and severity of complications and outcomes primarily depend on the efficiency and timeliness of blood transfusions, along with the speed of surgical arrest of bleeding. This publication describes in detail the main points of management of patients with massive bleeding according to modern international standards and Ukraine regulatory documents.

The analysis results define the prerogative of combined telescopic designs with axisymmetric accommodation of compression stresses, which enable reconstruction and stabilization of the spinal motion segment without additional fixation by a ventral plate. The classification of endoprostheses enables evaluation of advantages and disadvantages of various implants to objectively assess the mechanisms of potential postoperative complications and to prevent them. The presented data may facilitate the optimal choice of an implant with allowance for the peculiarities of a clinical situation in each particular case.