Effect of Insertional Direction of Pedicle Screw on Screw Loosening: A Biomechanical Study on Synthetic Bone Vertebra under a Physiology-like Load

Abstract

Objectives: It is now understood that pedicle screw loosening at the implant-bone interface can lead to poor screw–bone interface purchase and decreased fixation stability. Previous biomechanical tests used cadaveric vertebrae and pull-out or torque loads to assess the effect of the insertional direction of pedicle screws on screw loosening. However, these tests faced challenges in matching biomechanical differences among specimens and simulating in vivo loads applied on pedicle screws. This study aimed to evaluate the effect of the insertional direction of pedicle screws on screw loosening using tension-compression-bending loads and synthetic bone vertebrae.

Methods: Polyaxial pedicle screws were inserted into nine synthetic bone vertebrae in three directions (three samples per group): cranial, parallel, and caudad (-10°, 0°, +10° of the pedicle screw rod to the upper plane of the vertebra, respectively). Pedicle screws in the vertebrae were loaded using a polyethylene block connected to a material testing machine. Tension-compression-bending loads (100N–250N) with 30,000 cycles were applied to the pedicle screws, and displacements were recorded and then cycle-displacement curve was drawn based on cycle number. Micro-CT scans were performed on the vertebrae after removing the pedicle screws to obtain images of the screw hole, and the screw hole volume was measured using imaging analysis software. Direct comparison of displacements was conducted via cycle-displacement curve. Screw hole volume was analyzed using analysis of variance. The correlation between the displacement, screw hole volume and the direction of pedicle screw was assessed by Spearman correlation analysis.

Results: The smallest displacements were observed in the caudad group, followed by the parallel and cranial groups. The caudad group had the smallest screw hole volume (p < 0.001 and p = 0.009 compared to the cranial and parallel groups, respectively), while the volume in the parallel group was greater than that in the cranial group (p = 0.003). Correlation analysis revealed that the insertional direction of the pedicle screw was associated with the displacement (p = -0.949, p < 0.001) and screw hole volume (p = -0.944, p < 0.001).

Conclusion: Strong correlations were found between the insertional direction of the pedicle screw and relevant parameters, including displacement and screw hole volume. Pedicle screw insertion in the caudad direction resulted in the least pedicle screw loosening.

Keywords

Insertional direction of pedicle screw / Pedicle screw loosening / Synthetic bone vertebra / Tension-compression-bending load

References

[1] ZhangC, Gullbrand SE, SchaerTP, BoormanS, Elliott DM, ChenW, et al. Combined hydrogel and mesenchymal stem cell therapy for moderate-severity disc degeneration in goats. Tissue Eng Part A. 2021;27:117–128.

[2] ZhengJ, ZhangJ, ZhangX, Guo Z, WuW, ChenZ, et al. Reactive oxygen species mediate low Back pain by upregulating substance P in intervertebral disc degeneration. Oxid Med Cell Longev. 2021;2021: 6681815.

[3] LiuY, TanQ, QinJ, CaiY, NingN, Zhang R, et al. Prophylactic use of antibiotics for fever after drainage removal following a Dural tear during lumbar spinal surgery: a retrospective study. Med Sci Monit. 2022;28:e936652.

[4] VaccaroAR, HarrisJA, HussainMM, Wadhwa R, ChangVW, SchroerluckeSR, et al. Assessment of surgical procedural time, pedicle screw accuracy, and clinician radiation exposure of a novel robotic navigation system compared with conventional open and percutaneous freehand techniques: a cadaveric investigation. Global Spine J. 2020;10:814–825.

[5] WangJ, ZhangQ. Beware of brucella spondylitis following vertebroplasty: an unusual case of osteoporotic vertebral compression fracture. Infect Drug Resist. 2022;15:2565–2572.

[6] GalbuseraF, Volkheimer D, ReitmaierS, Berger-RoscherN, KienleA, WilkeHJ. Pedicle screw loosening: a clinically relevant complication? Eur Spine J. 2015;24:1005–1016.

[7] UeharaM, Takahashi J, IkegamiS, KuraishiS, Shimizu M, FutatsugiT, et al. Pedicle screw loosening after posterior spinal fusion for adolescent idiopathic scoliosis in upper and lower instrumented vertebrae having major perforation. Spine (Phila Pa 1976). 2017;42(24):1895–1900.

[8] XieY, MaH, LiH, DingW, ZhaoC, Zhang P, et al. Comparative study of unilateral and bilateral pedicle screw fixation in posterior lumbar interbody fusion. Orthopedics. 2012;35:e1517–e1523.

[9] MehmanparastH, PetitY, Mac-ThiongJM. Comparison of pedicle screw loosening mechanisms and the effect on fixation strength. J Biomech Eng. 2015;137:121003.

[10] YuanQ, HanX, HanX, HeD, LiuB, TianW. Krag versus caudad trajectory technique for pedicle screw insertion in osteoporotic vertebrae: biomechanical comparison and analysis. Spine (Phila Pa 1976). 2014;39(26):B27–B35.

[11] XuF, ZouD, LiW, SunZ, JiangS, Zhou S, et al. Hounsfield units of the vertebral body and pedicle as predictors of pedicle screw loosening after degenerative lumbar spine surgery. Neurosurg Focus. 2020;49:E10.

[12] LeeKY, LeeJH, KangKC, Shin SJ, ShinWJ, ImSK, et al. Strategy for obtaining solid fusion at L5-S1 in adult spinal deformity: risk factor analysis for nonunion at L5-S1. J Neurosurg Spine. 2020;1-9:323–331.

[13] ShinHK, KooHW, KimKH, Yoon SW, SohnMJ, LeeBJ. The usefulness of trabecular CT attenuation measurement at L4 level to predict screw loosening after degenerative lumbar fusion surgery: consider number of fused levels and postoperative sagittal balance. Spine (Phila Pa 1976). 2022;47(10):745–753.

[14] YoussefJA, McKinley TO, YerbySA, McLainRF. Characteristics of pedicle screw loading. Effect of sagittal insertion angle on intrapedicular bending moments. Spine (Phila Pa 1976). 1999;24(11):1077–1081.

[15] PatelPS, Shepherd DE, HukinsDW. The effect of screw insertion angle and thread type on the pullout strength of bone screws in normal and osteoporotic cancellous bone models. Med Eng Phys. 2010;32:822–828.

[16] RiosD, Patacxil WM, PalmerDK, WilliamsPA, ChengWK, InceoğluS. Pullout analysis of a lumbar plate with varying screw orientations: experimental and computational analyses. Spine (Phila Pa 1976). 2012;37(16):E942–E948.

[17] ÇetinE, Özkaya M, GülerÜ, AcaroğluE, Demir T. Evaluation of the effect of fixation angle between Polyaxial pedicle screw head and rod on the failure of screw-rod connection. Appl Bionics Biomech. 2015;2015:150649.

[18] TsouknidasA. The effect of pedicle screw implantation depth and angle on the loading and stiffness of a spinal fusion assembly. Biomed Mater Eng. 2015;25:425–433.

[19] AmiroucheF, Solitro GF, MagnanBP. Stability and spine pedicle screws fixation strength-a comparative study of bone density and insertion angle. Spine Deform. 2016;4:261–267.

[20] KrishnanV, Varghese V, KumarGS. Comparative analysis of effect of density, insertion angle and reinsertion on pull-out strength of single and two pedicle screw constructs using synthetic bone model. Asian Spine J. 2016;10:414–421.

[21] NewcombAG, BaekS, KellyBP, Crawford NR. Effect of screw position on load transfer in lumbar pedicle screws: a non-idealized finite element analysis. Comput Methods Biomech Biomed Engin. 2017;20:182–192.

[22] VargheseV, Saravana Kumar G, KrishnanV. Effect of various factors on pull out strength of pedicle screw in normal and osteoporotic cancellous bone models. Med Eng Phys. 2017;40:28–38.

[23] VargheseV, Krishnan V, KumarGS. Evaluating pedicle-screw instrumentation using decision-tree analysis based on pullout strength. Asian Spine J. 2018;12:611–621.

[24] AkgülT, Korkmaz M, PehlivanogluT, BayramS, Özdemir MA, KaralarŞ. Biomechanical comparison of pull-out strength of different cementation and pedicle screw placement techniques in a calf spine model. Indian J Orthop. 2020;54:134–140.

[25] MolinariL, Falcinelli C, GizziA, Di MartinoA. Effect of pedicle screw angles on the fracture risk of the human vertebra: a patient-specific computational model. J Mech Behav Biomed Mater. 2021;116:104359.

[26] RohlmannA, Bergmann G, GraichenF. Loads on an internal spinal fixation device during walking. J Biomech. 1997;30:41–47.

[27] RohlmannA, Graichen F, WeberU, BergmannG. Volvo award winner in biomechanical studies: monitoring in vivo implant loads with a telemeterized internal spinal fixation device. Spine (Phila Pa 1976). 2000;2000(25):2981–2986.

[28] ChoW, ChoSK, WuC. The biomechanics of pedicle screw-based instrumentation. J Bone Joint Surg Br. 2010;92:1061–1065.

[29] LawM, TencerAF, AndersonPA. Caudo-cephalad loading of pedicle screws: mechanisms of loosening and methods of augmentation. Spine (Phila Pa 1976). 1993;18(16):2438–2443.

[30] CunninghamBW, SefterJC, ShonoY, McAfee PC. Static and cyclical biomechanical analysis of pedicle screw spinal constructs. Spine (Phila Pa 1976). 1993;18(12):1677–1688.

[31] TanJS, KwonBK, DvorakMF, Fisher CG, OxlandTR. Pedicle screw motion in the osteoporotic spine after augmentation with laminar hooks, sublaminar wires, or calcium phosphate cement: a comparative analysis. Spine (Phila Pa 1976). 2004;29(16):1723–1730.

[32] Standard Test Methods for Spinal Implant Constructs in a Vertebrectomy Model. 2021.

[33] SinghP, Telnova S, ZhouB, MohamedAD, MelloVD, WackerhageH, et al. Maternal vitamin B(12) in mice positively regulates bone, but not muscle mass and strength in post-weaning and mature offspring. Am J Physiol Regul Integr Comp Physiol. 2021;320:R984–r993.

[34] NowakB. Experimental study on the loosening of pedicle screws implanted to synthetic bone vertebra models and under non-pull-out mechanical loads. J Mech Behav Biomed Mater. 2019;98:200–204.

[35] KoltaS, Kerkeni S, TravertC, SkalliW, Eastell R, GlüerCC, et al. Variations in vertebral body dimensions in women measured by 3D-XA: a longitudinal in vivo study. Bone. 2012;50:777–783.

[36] HouS, HuR, ShiY. Pedicle morphology of the lower thoracic and lumbar spine in a Chinese population. Spine (Phila Pa 1976). 1993;18(13):1850–1855.

[37] MiyashitaT, AtakaH, KatoK, Takaoka H, TannoT. Pedicle screw shift without loosening following instrumented posterior fusion: limitations of pedicle screw fixation. Neurosurg Rev. 2019;42:691–698.

[38] HaizhouW, Hongwei L, ShuangW, NanJ, ShuaiW. Characteristics of lower lumbar pedicle screw angle in Chinese population using digital technology. Chin J Tissue Eng Res. 2015;19:5723–5727.

[39] XiX, ZengZ, LiF, WangC, MaB, XieN, et al. Caudad insertion of pedicle screws facilitates interbody distraction during Spondylolisthetic vertebrae restoration: a retrospective study. Pain Ther. 2021;10:1537–1550.

[40] ChomaTJ, Frevert WF, CarsonWL, WatersNP, Pfeiffer FM. Biomechanical analysis of pedicle screws in osteoporotic bone with bioactive cement augmentation using simulated in vivo multicomponent loading. Spine (Phila Pa 1976). 2011;36(6):454–462.

[41] NagarajaS, PalepuV. Integrated fixation cage loosening under fatigue loading. Int J Spine Surg. 2017;11:20.

[42] ZhangT, RenX, FengX, Diwan A, LukKDK, LuWW, et al. Failure mechanisms of pedicle screws and cortical screws fixation under large displacement: a biomechanical and microstructural study based on a clinical case scenario. J Mech Behav Biomed Mater. 2020;104:103646.

[43] ZenkertD, BurmanM. Fatigue of closed-cell foams in compression. J Sandw Struct Mater. 2011;13:467–478.

[44] WangWT, GuoCH, DuanK, Ma MJ, JiangY, LiuTJ, et al. Dual pitch titanium-coated pedicle screws improve initial and early fixation in a polyetheretherketone rod semi-rigid fixation system in sheep. Chin Med J (Engl). 2019;132:2594–2600.

[45] SchulzeM, Gehweiler D, RiesenbeckO, WähnertD, Raschke MJ, HartensuerR, et al. Biomechanical characteristics of pedicle screws in osteoporotic vertebrae-comparing a new cadaver corpectomy model and pure pull-out testing. J Orthop Res. 2017;35:167–174.

[46] SongF, LiuY, FuR, GaoX, IqbalK, Yang D, et al. Craniocaudal toggling increases the risk of screw loosening in osteoporotic vertebrae. Comput Methods Programs Biomed. 2023;238:107625.

[47] YuanQ, XingY, TaoJ, ChenD, TianW. The direction of pedicle screws in osteoporotic lumbar vertebrae on stability of internal fix. Shandong Pharm. 2009;49:19–22.

[48] ShiK, LeiY, WangH, Yu Z. Biomechanical study of pull——out force on pedicle screws of different sagittal angles. Chin J Bone Joint Injury. 2009;24:311–313.

[49] WuSS, Edwards WT, YuanHA. Stiffness between different directions of transpedicular screws and vertebra. Clin Biomech (Bristol, Avon). 1998;13:S1–s8.

[50] MatsukawaK, YatoY, ImabayashiH. Impact of screw diameter and length on pedicle screw fixation strength in osteoporotic vertebrae: a finite element analysis. Asian Spine J. 2021;15:566–574.

[51] HuangJC, XuanWB, QianBP, Qiu Y, WangB, YuY, et al. Pedicle morphology of lower thoracic and lumbar spine in ankylosing spondylitis patients with thoracolumbar kyphosis: a comparison with fracture patients. Orthop Surg. 2022;14:2188–2194.

[52] KukloTR, PotterBK, PollyDW, Lenke LG. Monaxial versus multiaxial thoracic pedicle screws in the correction of adolescent idiopathic scoliosis. Spine (Phila Pa 1976). 2005;30(18):2113–2120.

[53] HeL, XiangQ, YangY, Tsai TY, YuY, ChengL. The anterior and traverse cage can provide optimal biomechanical performance for both traditional and percutaneous endoscopic transforaminal lumbar interbody fusion. Comput Biol Med. 2021;131:104291.

[54] LeeYH, ChungCJ, WangCW, Peng YT, ChangCH, ChenCH, et al. Computational comparison of three posterior lumbar interbody fusion techniques by using porous titanium interbody cages with 50% porosity. Comput Biol Med. 2016;71:35–45.

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