EXPERIMENTAL GROUND OF MODIFIED FIXATOR APPLICATION FOR ANTERIOR INTERBODY SPONDYLODESIS IN LOW THORACIC AND LUMBAR VERTEBRAE COMMINUTED FRACTURES

A.B. MAKAROV ¹, K.S. SERGEEV ², D.V. DEREVIANKO ³

Municipal Institution “Central Town Hospital, Noyabrsk, RUSSIA¹

Tyumen State Medical Academy, Tyumen, RUSSIA²

Municipal Budget Institution “City Hospital №1, Novorossiysk, RUSSIA³

Introduction: Trauma of thoracolumbar part of spinal column takes leading place in structure of spinal pathology. It is impossible to restore normal anatomy of cerebrospinal canal and spinal column without surgery. Anterior interbody spondylodesis in comminuted fractures of thoracolumbar part of spinal column is the most biomechanically and pathogenically reasonable method of treatment. Problems of bony block delayed formation or total nonunion after operative treatment of thoracolumbar fractures are still unsolved. At the Department of Traumatology and Orthopaedics and Military-Field Medicine of the Tyumen State Medical Academy (Tyumen, Russia) modified fixator for anterior interbody spondylodesis was constructed. It combines advantages of titanium implants with bioactive characteristics of hydroxyapatite as material which ensures bony-metal block formation for shorter time (positive decision for issuance of a patent for effective model according to entry № 2011109989/14(014559) dated 16/03/2011., Makarov A.B., Sergeev K.S., et al.).

Materials and methods: Standard and modified fixators intended for vertebra body replacement in anterior spondylodesis surgery were undergone with external loading during experiment. Control and basic samples were made of Titanium BT6. Modified implant was covered with hydroxyapatite by micro-arc oxidation. Control and basic samples were put between “Sawbones” (Sweden) polyurethane blocks for biomechanical tests used as vertebra body models. During adjustment of samples between vertebra body models axis of symmetry of fixators coincided with axis of symmetry of vertebra body models. Compression tests with universal dynamometer “Instron 1185” (USA) were performed. Acceleration moments of rise of deformation were recorded in acquired load curves. It corresponded to the beginning of destruction of blocks for biomechanical tests used as vertebra body models.

Results: Press force necessary for a vertebra body model being destroyed was statistically reliable higher (p≤0.05) if an innovated fixator for anterior spondylodesis was used.

Conclusion: The offered modified interbody implant for anterior spondylodesis statistically reliable increases implant-bone system stability and helps to keep achieved deformity correction. Features of construction and implant fixation to a bone bed should help to improve outcome of anterior spondylodesis surgery in low thoracic and lumbar vertebrae comminuted fractures.

Date: 2014-12-28; view: 872