Popov A. Surgical restoration of the support function of the spine in patients with thoracic and lumbar tumour lesions.

Object: support ability of the spine in case of tumors in the thoracic and lumbar vertebrae. Aim: to improve the results of surgical restoration of the support function of the spine in patients with tumorous lesions of the thoracic and lumbar vertebrae by experimental and clinical reasoning of stabilization techniques and the choice of the surgery extent based on the definition of statistically significant clinical signs. Methods: clinical; radiological; computed tomography, magnetic resonance imaging, biomechanical, mathematical modeling using the finite element method; experimental modeling on animals; histological; statistical. It was established for the first time that the level of damage of the vertebrae, size of local kyphosis and posterior wall deformity of the vertebrae is the important morphological characters that determine anatomical changes in the structures of the functional spinal unit in case of tumor. Statistically significant prognostic criteria was defined for the first time and an algorithm for selecting the extent of surgical management in patients with spinal neoplasms was proved by personalisation of diagnostic data of patients and mathematical modeling too. The effectiveness of different types of surgery — vertebroplasty; combined posterior spine fusion (one vertebra from above and one vertebra from below with vertebroplasty; two vertebrae from above, two vertebrae from below, one or two vertebrae from above, one or two vertebrae from below with a cage) was proved for the first time, based on the developed mathematical models for various types of tumorous lesions of the vertebrae on thoracic and lumbar regions of the spine. The dependence of the indications for different types of surgery to restore the spine support function to the extent of tumor stricken was established for the first time. The mechanical effectiveness of transpedicular constructions with different numbers of fixed functional spinal units in supportability loss of anterior support complex of thoracic and the lumbar spine was proved for the first time. The high level osseointegration in carbon implants with pyrocarbon coating was experimentally proved for the first time. Their evidence is based on the comparative histological analysis. New types of the endoprosthesis of the interbody spinal fusion of thoracic and lumbar spinal regions were developed from the perspective of the study of biomechanical, mathematical, and experimental biological models for the first time. For the first time, the effectiveness of the developed technique of puncture vertebroplasty for injuries of the posterior wall of the vertebrae of the thoracic and lumbar spine affected by the tumor process, as well as the technique of instrumental fixation of the functional links of the spine with bone cement using puncture vertebroplasty has been clinically proven. The developed algorithm of selecting the extent of surgery of spinal tumors allow with a high probability to choose the appropriate extent of surgical interference for a patient with spinal neoplasm to ensure suitable treatment outcome. A combined endoprosthesis made from carbon composite has been developed (patents №. 115715 and 120318, Ukraine). It allows to improve the results of treatment of patients with tumor lesions of thoracic and lumbar spine and control the dynamics of the tumor process in the surgical area. A developed telescope-type endoprosthesis made from carbon composite (patent №.142816, Ukraine) allows to improve the results of treatment the patients with tumor lesions of thoracic and lumbar regions of the spine and control the dynamics of the tumor process in the surgical area. Several techniques for surgical management of patients with tumors of thoracic and lumbar regions of the spine have been offered and improved (pat. 135420, 139899, Ukraine). The developed 3D models of thoracic and lumbar regions of the spine can be used in further scientific research on spinal injuries of any genesis. The improved and developed methods and equipment for needle biopsy of the spine (pat. 107095, 107106, 97998 Ukraine) allows to obtain a biopsy sample in a sufficient quantity and quality apart from the tissue density and increase the diagnostic result up to 96 %. The use of a posterior spine fusion scheme if faced with the loss of supportability in the anterior thoracic and lumbar regions of the spine offers an opportunity to improve surgery management outcomes in patients with spinal tumors. The results of the research are introduced into the scientific process of the Department of Traumatology and Orthopedics of the Kharkiv Medical Academy of Postgraduate Education of the Ministry of Health of Ukraine and clinical practice of the Sytenko Institute of Spine and Joint Pathology of the National Academy of Medical Sciences of Ukraine (Kharkiv), Educational and Scientific Medical Complex "University Clinic" of the National Kharkiv Medical University. Traumatology and Orthopaedics.