Biomechanical State of the Operated Thoracolumbar Junction in Lateroflexion
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finite element model
thoracolumbar junction
bicortical transpedicular stabilization

How to Cite

Nekhlopochyn, O., Cheshuk, Y., Vorodi, M., Tsymbaliuk, Y., Karpinskyi, M., & Yaresko, O. (2022). Biomechanical State of the Operated Thoracolumbar Junction in Lateroflexion. TERRA ORTHOPAEDICA, (2(113), 58-67.


Summary. The zone of the thoracolumbar junction is the most susceptible to traumatic injuries due to anatomical and physiological features. Accordingly, the stabilization of this section of the spine requires high reliability.

Objective: to study the stress-strain state of the model of the thoracolumbar spine after resection of Th12-L1 vertebrae with different types of transpedicular fixation under lateroflexion.

Materials and Methods. Mathematical finite element model of a fragment of the human thoracolumbar spine (Тh9-L5) was developed. We modeled the result of decompressive-stabilizing surgery with total removal of Th12-L1 vertebrae including installation of vertebral body replacing implant and fixation with a transpedicular system using 4 pairs of screws. Lateroflexion was modeled by applying a load of 350 N.

Results. When evaluating the model without crosslinks and using monocortical pedicle screws, it was found that the maximum loading values in Th10, Th11, L2, and L3 vertebral bodies were 3.4, 2.0, 3.5, and 8.6 MPa, respectively; loading on pedicle screws installed in the indicated vertebrae was 48.4, 48.3, 23.3 and 43.5 MPa. When using bicortical screws without crosslinks in the vertebral bodies, the values were 3.1, 2.5, 3.8, 9.6 MPa and 49.9, 51.9, 25.8, 44.8 MPa, respectively; when using a combination of short screws and crosslinks in the vertebral bodies, the values were 3.2, 2.0, 2.6, 7.5 MPa and 47.6, 47.5, 22.6, 41.2 MPa, respectively; when using crosslinks and bicortical screws, the values were 3.0, 2.2, 2.7, 8.8 MPa and 48.3, 49.6, 24.3, 42.5 MPa, respectively.

Conclusions. In lateroflexion, monocortical pedicle screws cause lower critical loading rates compared to long screws at all control points of the model. Crosslinks help to reduce stress levels. The use of monocortical pedicle screws in combination with transverse ties seems to be the most biomechanically effective in lateroflexion.
ARTICLE PDF (Українська)


Platt H. Fractures and Dislocations of the Spine. British medical journal. 1938;2(4065):1155-1158. DOI: 10.1136/bmj.2.4065.1155, PMID: 20781938.

Xu GJ, Li ZJ, Ma JX, Zhang T, Fu X, Ma XL. Anterior versus posterior approach or treatment of thoracolumbar burst fractures: a meta-analysis. Eur Spine J. 2013;22(10):2176-2183. DOI: 10.1007/s00586-013-2987-y, PMID: 24013718.

Davis AG. Fractures of the spine. The Journal of Bone & Joint Surgery. 1929;11(1):133-156.

Kelly RP, Whitesides TE, Jr. Treatment of lumbodorsal fracture-dislocations. Ann Surg. 1968;167(5):705-717. DOI: 10.1097/00000658-196805000-00009, PMID: 5646292.

Hodgson AR, Stock FE. Anterior spinal fusion a preliminary communication on the radical treatment of Pott's disease and Pott's paraplegia. The British journal of surgery. 1956;44(185):266-275. DOI: 10.1002/bjs.18004418508, PMID: 13383153.

King D. Internal fixation for lumbosacral fusion. J Bone Joint Surg Am. 1948;30a(3):560-565. PMID: 18109577.

Boucher HH. A method of spinal fusion. J Bone Joint Surg Br. 1959;41-b(2):248-259. DOI: 10.1302/0301-620x.41b2.248, PMID: 13641310.

Roy-Camille R, Saillant G, Mazel C. Internal fixation of the lumbar spine with pedicle screw plating. Clin Orthop Relat Res. 1986(203):7-17. PMID: 3955999.

Liu J, Yang S, Lu J, Fu D, Liu X, Shang D. Biomechanical effects of USS fixation ith different screw insertion depths on the vertebrae stiffness and screw stress for the treatment of the L1 fracture. J Back Musculoskelet Rehabil. 2018;31(2):285-297. DOI: 10.3233/bmr-169692, PMID: 29332029.

Shibasaki Y, Tsutsui S, Yamamoto E, Murakami K, Yoshida M, Yamada H. A bicortical pedicle screw in the caudad trajectory is the best option for the fixation of an osteoporotic vertebra: An in-vitro experimental study using synthetic lumbar osteoporotic bone models. Clin Biomech (Bristol, Avon). 2020;72:150-154. DOI: 10.1016/j.clinbiomech.2019.12.013, PMID: 3187753.

Cornaz F, Widmer J, Snedeker JG, Spirig JM, Farshad M. Cross-links in posterior pedicle screw-rod instrumentation of the spine: a systematic review on mechanical, biomechanical, numerical and clinical studies. Eur Spine J. 2021;30(1):34-49. DOI: 10.1007/s00586-020-06597-z, PMID: 33009949.

Nekhlopochyn OS, Verbov VV, Karpinsky MY, Yaresko OV. Biomechanical evaluation of the pedicle screw insertion depth and role of cross-link in thoracolumbar junction fracture surgery: a finite element study under compressive loads. Ukrainian Neurosurgical Journal. 2021;27(3):25-32. DOI: 10.25305/unj.230621.

Nekhlopochin A, Nekhlopochin S, Karpinsky M, Shvets A, Karpinskaya E, Yaresko A. Mathematical Analysis and Optimization of Design Characteristics of Stabilizing Vertebral Body Replacing Systems for Subaxial Cervical Fusion Using the Finite Element Method. Hirurgiâ pozvonočnika. 2017;14(1):37-45. DOI: 10.14531/ss2017.1.37-45.

Cowin SC. Bone Mechanics Handbook. 2nd ed. Boca Raton: CRC Press; 2001.

Boccaccio A, Pappalettere C. Mechanobiology of Fracture Healing: Basic Principles and Applications in Orthodontics and Orthopaedics. In: Klika V, editor. Theoretical Biomechanics 2011.

Niinomi M. Mechanical biocompatibilities of titanium alloys for biomedical applications. J Mech Behav Biomed Mater. 2008;1(1):30-42. 8/31/2022: DOI:10.1016/j.jmbbm.2007.07.001, PMID: 19627769.

Obraztsov IF, Adamovich IS, Barer IS. Problemy prochnosti v biomekhanike. Moscow: Vysshaya shkola; 1988. [in Russian].

Zenkevich OK. Metod konechnykh elementov v tekhnike. Moscow: Mir; 1975. [in Russian].

Alyamovskiy AA. SolidWorks/COSMOSWorks. Inzhenernyy analiz metodom konechnykh elementov. Moscow: DMK Press; 2004. [in Russian].

Ghanayem AJ, Zdeblick TA. Anterior instrumentation in the management of thoracolumbar burst fractures. Clin Orthop Relat Res. 1997(335):89-100. PMID: 9020209.

Hoffmann C, Spiegl UJ, Paetzold R, Devitt B, Hauck S, Weiss T, et al. Long- term results after thoracoscopic anterior spondylodesis with or without posterior stabilization of unstable incomplete burst fractures of the thoracolumbar junction: a prospective cohort study. Journal of orthopaedic surgery and research.2020;15(1):412. DOI: 10.1186/s13018-020-01807-2, PMID: 32933516.

Vicenty JC, Saavedra FM, Vigo JA, Pastrana EA. Circumferential Stabilization of the Thoracolumbar Junction Via Posterior-Only Approach for the Management of Burst Fractures. Puerto Rico health sciences journal. 2018;37(4):224-229. PMID: 30548059.

Mina A, Mohammed RAK. Biomechanical Evaluation of Segmental Pedicle Screw Fixation in Thoracolumbar Fracture: A Finite Element Study. Orthopedics and Rheumatology Open Access Journal. 2018;12(3). DOI: 10.19080/oroaj.2018.12.555838.

Kuklo TR, Dmitriev AE, Cardoso MJ, Lehman RA, Jr., Erickson M, Gill NW. Biomechanical contribution of transverse connectors to segmental stability following long segment instrumentation with thoracic pedicle screws. Spine (Phila Pa 1976). 2008;33(15):E482-487. DOI: 10.1097/BRS.0b013e31817c64d5, PMID: 18594445.

Wang T, Cai Z, Zhao Y, Wang W, Zheng G, Wang Z, et al. The Influence of Cross-Links on Long-Segment Instrumentation Following Spinal Osteotomy: A Finite Element Analysis. World Neurosurg. 2019;123:e294-e302. DOI: 10.1016/j.wneu.2018.11.154, PMID: 30496922.

Lynn G, Mukherjee DP, Kruse RN, Sadasivan KK, Albright JA. Mechanical stability of thoracolumbar pedicle screw fixation. The effect of crosslinks. Spine (Phila Pa 1976). 1997;22(14):1568-1572; discussion 1573. 31.08.2022: 10.1097/00007632-199707150-00007, PMID: 9253090.

Xu C, Hou Q, Chu Y, Huang X, Yang W, Ma J, et al. How to improve the afety of bicortical pedicle screw insertion in the thoracolumbar vertebrae: analysis base on three-dimensional CT reconstruction of patients in the prone position. BMC Musculoskelet Disord. 2020;21(1):444. DOI: 10.1186/s12891-020-03473-1, PMID: 32635944.

Chen C-S, Chen W-J, Cheng C-K, Jao S-HE, Chueh S-C, Wang C-C. Failure analysis of broken pedicle screws on spinal instrumentation. Medical Engineering ysics. 2005;27(6):487-496. DOI: 10.1016/j.medengphy.2004.12.007.

Galbusera F, Volkheimer D, Reitmaier S, Berger-Roscher N, Kienle A, Wilke HJ. Pedicle screw loosening: a clinically relevant complication? Eur Spine J. 2015;24(5):1005-1016. DOI: 10.1007/s00586-015-3768-6, PMID: 25616349.

Matsuzaki H, Tokuhashi Y, Matsumoto F, Hoshino M, Kiuchi T, Toriyama S. Problems and solutions of pedicle screw plate fixation of lumbar spine. Spine (Phila Pa 1976). 1990;15(11):1159-1165. DOI: 10.1097/00007632-199011010-00014, PMID: 2267611.

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