Authors
Aslanov R.A. 1, Donnik A.M.2, Dulaev A.K.3, 4, Kutyanov D.I.3, 4, Davydov D.V.1, Brizhan L.K.1, Pimanchev O.V.5
1 Main Military Clinical Hospital named after academician Burdenko N.N., Moscow
2 Saratov National Research State University named after Chernyshevsky N.G., Saratov
3 First St. Petersburg State Medical University named after academician Pavlov I.P., St. Petersburg
4 St. Petersburg Dzhanelidze Research Institute of Emergency Care, St. Petersburg
5 Pirogov National Medical and Surgical Center, Moscow
Abstract
Rationale: An objective trend in modern spine trauma surgery is to provide the best conditions for recreating and maintaining normal biomechanics of the spinal column while reducing the length of fixation and the amount of surgical trauma. At the same time, the data on the biomechanical efficacy of the existing methods of short-segment pedicle spinal instrumentation are contradictory, which necessitates further experimental design and research.
Objective: Based on the results of three-dimensional finite element analysis, to conduct a comparative biomechanical assessment of the efficacy of the new method of short-segment multi-rod posterior internal instrumental fixation of lumbar burst fractures that was developed by the authors and involves the combined use of pedicle screw and laminar hook systems.
Methods: A model of the spinal segment from the T12 to L4 vertebrae with cartilaginous and ligamentous structures connecting them and a complete burst fracture (type A4 injury according to the AO classification) of the L2 vertebra was created using the finite element method. Three variants of posterior instrumental fixation were modeled on its basis: 1) Comparison model – extended pedicle screw fixation with screws inserted in pairs into the T12, L1, L3, and L4 vertebral bodies; 2) Type I experimental model – short pedicle screw fixation at the level of the L1–L3 vertebrae with two screws in the injured L2 vertebra; laminar hook fixation of the L1 and L3 vertebrae with a distractor and contractor; 3) Type II experimental model – pedicle screw fixation at the level of the L1–L3 vertebrae without inserting screws into the fractured vertebral body; laminar hook fixation of the L1 and L3 vertebrae with the position of hooks in the form of a staple providing a circular grasp on the half-arch. Each model was subjected to six types of loads: standing position, flexion, extension, lateral flexion to the right, lateral flexion to the left, axial rotation to the right, and axial rotation to the left. Mimics (version 21, Materialise), 3-Matic (version 21, Materialise), SolidWorks (2018), and ANSYS 19.2 software were used in this work.
Results: In terms of rigidity and fixation strength, the new method of posterior spinal instrumentation in either of its two variants is superior to long-segment pedicle systems traditionally used for lumbar burst fractures and, in addition to reducing the length of the immobilized part of the spine, provides greater stability of the fragments of the fractured vertebra as well as of the injured spine motion segment as a whole.
Conclusion: Extrapolating these results to clinical practice, the proposed method of spinal instrumentation with pedicle screw fixation of the fractured vertebra and laminar hook fixation of adjacent vertebrae with a distractor and contractor should be considered optimal. If it is impossible to insert screws into the fractured vertebra, modification of the new method with an increased number of laminar hook system supports is an efficacious alternative to long-segment fixation.
Keywords: lumbar burst fracture, posterior internal instrumental fixation, multi-rod short-segment fixation, pedicle screw fixation, laminar hook fixation, finite element analysis.
References
1. Parshin MS. Optimizatsiya taktiki khirurgicheskogo lecheniya postradavshikh s izolirovannymi neoslozhnennymi «vzryvnymi» perelomami grudnykh i poyasnichnykh pozvonkov. [dissertation] Saint Petersburg; 2019. (In Russ.)
2. Cheng LM, Wang JJ, Zeng ZL, et al. Pedicle screw fixation for traumatic fractures of the thoracic and lumbar spine. Cochrane Database Syst Rev. 2013; 5: CD009073. doi: 10.1002/14651858.CD009073.pub2.
3. Kanna RM, Shetty AP, Rajasekaran S. Posterior fixation including the fractured vertebra for severe unstable thoracolumbar fractures. Spine J. 2015; 15(2): 256-264. doi: 10.1016/j.spinee.2014.09.004.
4. Patent RUS №2749823/17.06.2021. Byul. №17. Dulayev AK, Aslanov RA, Brizhan’ LK, Davydov DV, Kutyanov DI, Alikov ZYu. Sposob vnutrenney fiksatsii nestabil’nykh neoslozhnennykh vzryvnykh perelomov poyasnichnykh pozvonkov (In Russ).
5. Sun XY, Zhang XN, Hai Y. Percutaneous versus traditional and paraspinal posterior open approaches for treatment of thoracolumbar fractures without neurologic deficit: a meta-analysis. Eur. Spine J. 2017; 26(5): 1418-1431. doi: 10.1007/s00586-016-4818-4.
6. Donnik AM, Kossovich LYu, Olenco ES. Behavior of the segment of the thoracic spine in comparated vertebral fracture before and after surgical treatment. Biomechanical experiment. Russian Journal of Biomechanics. 2022; 26(1): 21-34. (In Russ.) doi: 10.15593/RZhBiomeh/2022.1.02.
7. Putzer MA, Auer S, Malpica W, et al. A numerical study to determine the effect of ligament stiffness on kinematics of the lumbar spine during flexion. BMC Musculoskelet Disord. 2016; 17: 95. doi: 10.1186/s12891-016-0942-x.
8. Liao JC, Chen WP, Wang H. Treatment of thoracolumbar burst fractures by short-segment pedicle screw fixation using a combination of two additional pedicle screws and vertebroplasty at the level of the fracture: a finite element analysis. BMC Musculoskelet Disord. 2017; 18(1): 262. doi: 10.1186/s12891-017-1623-0.
9. Liao JC. Impact of osteoporosis on different type of short-segment posterior instrumentation for thoracolumbar burst fracture — a finite element analysis. World Neurosurg. 2020; 139: e643-e651. doi: 10.1016/j.wneu. 2020.04.056.
10. Wu Y, Chen CH, Tsuang FY, et al. The stability of long-segment and short-segment fixation for treating severe burst fractures at the thoracolumbar junction in osteoporotic bone: A finite element analysis. PLoS One. 2019; 14(2): e0211676. doi: 10.1371/journal.pone.0211676.
11. Wong CE, Hu HT, Huang YH, Huang KY. Optimization of spinal reconstructions for thoracolumbar burst fractures to prevent proximal junctional complications: A finite element study. Bioengineering (Basel). 2022; 9(10): 491. doi: 10.3390/bioengineering9100491.
12. Limthongkul W, Wannaratsiri N, Sukjamsri C, et al. Biomechanical comparison between posterior long-segment fixation, short-segment fixation, and short-segment fixation with intermediate screws for the treatment of thoracolumbar burst fracture: A finite element analysis. Int J Spine Surg. 2023; 17(3): 442-448. doi: 10.14444/8441.
13. Xia C, Yang S, Liu J, et al. Finite element study on whether posterior upper wall fracture is a risk factor for the failure of short-segment pedicle screw fixation in the treatment of L1 burst fracture. Injury. 2021; 52(11): 3253-3260. doi: 10.1016/j.injury.2021.08.020.
14. Dai LY, Jiang SD, Wang XY, Jiang LS. A review of the management of thoracolumbar burst fractures. Surg Neurol. 2007; 67(3): 221-231; discussion 231. doi: 10.1016/j.surneu.2006.08.081.
15. Basaran R, Efendioglu M, Kaksi M, et al. Finite Element Analysis of Short- Versus Long-Segment Posterior Fixation for Thoracolumbar Burst Fracture. World Neurosurg. 2019; 128: e1109-e1117. doi: 10.1016/j.wneu. 2019.05.077.
16. Elmasry S, Asfour S, Travascio F. Effectiveness of pedicle screw inclusion at the fracture level in short-segment fixation constructs for the treatment of thoracolumbar burst fractures: a computational biomechanics analysis / Comput Methods Biomech Biomed Engin. 2017; 20(13): 1412-1420. doi: 10.1080/10255842.2017.1366995.
17. Wang H, Mo Z, Han J, et al. Extent and location of fixation affects the biomechanical stability of short- or long-segment pedicle screw technique with screwing of fractured vertebra for the treatment of thoracolumbar burst fractures: An observational study using finite element analysis. Medicine (Baltimore). 2018; 97(26): e11244. doi: 10.1097/MD.0000000000011244.
18. Wang W, Pei B, Pei Y, et al. Biomechanical effects of posterior pedicle fixation techniques on the adjacent segment for the treatment of thoracolumbar burst fractures: a biomechanical analysis / Comput Methods Biomech Biomed Engin. 2019; 22(13): 1083-1092. doi: 10.1080/10255842.2019. 1631286.
19. Su Y, Wang X, Ren D, et al. A finite element study on posterior short segment fixation combined with unilateral fixation using pedicle screws for stable thoracolumbar fracture. Medicine (Baltimore). 2018; 97(34): e12046. doi: 10.1097/MD.0000000000012046.
20. Dulayev AK, Kutyanov DI, Manukovskiy VA, et al. Decision-making and technical choice in instrumental fixation for neurologically uncomplicated isolated burst fractures of the thoracic and lumbar vertebrae. Khirurgiya pozvonochnika. 2019; 16(2): 7–17. (In Russ.) doi: 10.14531/ss2019.2.7-17.
