ВступКлишоногість є тяжкою деформацією стопи, що знаходиться на першому місці серед вроджених захворювань опорно-рухового апарату. Народжуваність дітей із вродженою клишоногістю становить 0,1-0,4 % [1,2,4,8].Починаючи з кінця 80-х років, коли у всьому світі широкого визнання набула методика І. Ponseti, основним є раннє консервативне лікування з використанням етапних гіпсових пов'язок. Ефектив-Ïèòàííÿ äèòÿ÷î¿ õ³ðóð㳿, ³íòåíñèâíî¿ òåðàﳿ ³ ðåàí³ìàö³¿ ó ïðàêòèö³ ïåä³àòðà / Questions of Pediatric Surgery, Intensive Care and Resuscitation in Practice of Pediatrician ® ність даної методики досягає 93 % і дозволяє значно зменшити кількість хірургічних втручань [3, 6,7,[12][13][14].Проте пізній початок лікування, відсутність або недотримання режиму носіння брейсів, супутня неврологічна патологія призводять до зниження ефективності консервативного лікування та застосування в подальшому хірургічних методик. Згідно з даними літератури, частота рецидивів вродженої клишоногості в дітей в Україні і за кордоном зали-УДК 617. 586-007.5-053.1/.2

Background. Mathematical modeling of the correction of scoliotic deformities of the spine makes it possible to analyze the effectiveness of various methods of treatment without surgical intervention. In the study of traction, mainly experimental methods were used. The purpose was to investigate the stress-strain state of the spine models with varying degrees of scoliotic deformity during posterior spinal fusion. Materials and methods. Deformities of the spine of 40, 70 and 100° were modeled, with posterior spondylodesis of the Th1-Th12 vertebrae. A load of 300 N was used. Results. With a deformity of 40°, the most stressed are the areas of frontal plane curve. For the upper vertebrae Th1-Th4, a more even distribution of stress over the vertebral body is observed. For Th5-Th10 vertebrae, the concave side of the vertebral bodies is more stressed. In the thoracic spine, the more stressed vertebrae are Th2 and Th5. The main load is borne by the fixing structure, in which the level of stress is significantly higher than in the bone structures of the vertebrae. In the posterior supporting complex of the vertebrae, the stress concentration areas are located at the points where fixing screws enter the bone. An increase in the magnitude of the scoliotic deformity of the spine up to 70° causes an increase in the level of stresses in all elements of the model, with the exception of Th9-Th10 vertebrae. With a deformity of 100° in the posterior supporting complex of the vertebrae, the stress concentration areas are located at the points where fixing screws enter the bone. The stress level of 116.0 MPa exceeds the ultimate strength of the cortical layer of the bone tissue of the spine, which can lead to microdamage of the bone tissue and loosening of the screws. Conclusions. For all values of scoliotic deformity of the spine, the most stressed are Th4 and Th5 vertebrae. A decrease in the degree of deformity has a significant effect on the stress-strain state of the spinal column. In the Th4 vertebral body, the level of stresses with a deformity of 100° is more than twice as high as with a deformity of 70°, and more than 4 times higher than with a deformity of 40°. In the body of the Th5 vertebra, the stress level with a deformity of 70° is 1.5 times less than with a deformity of 100°, and with a deformity of 40°, it is 3 times less. The level of stress in the Th1-Th5 vertebral bodies is higher than that of Th6-Th12. In the posterior supporting complex, at the points where screws enter the bone, the maximum stress value at a deformity of 40° is 34.0 MPa, which is not critical for the bone tissue. With a deformity of 70°, the stresses are 85.0 MPa, which can exceed the ultimate strength for the cortical bone and lead to microdestruction of the bone tissue in the screw-bone contact area. With a deformity of 100°, the stresses are equal to 116.0 MPa, which exceeds the ultimate strength for the cortical bone and can lead to microfracture in the screw-bone contact area.