Comparison of insertion time, pull-out strength, and screw-media interface area of customized pedicle screw with different core and thread design against commercial pedicle screw: a pilot study on Indonesian Population

Abstract Objective This research aimed to developing customized pedicle screw based on Indonesian vertebral anatomy and compare the insertion time, pull-out strength, and screw-media interface area of different screw design. We have developed 3 different types of pedicle screws (v-thread cylinder-core, square-thread cylinder-core and square-thread conical-core). The thread diameter was calculated from pedicle width of Indonesian population (6 mm). We used commercially available pedicle screw as control group (6.2 mm). Result The insertion time were significantly difference between v-thread cylinder-core pedicle screw (22.94 s) with commercially available pedicle screw (15.86 s) (p < 0.05). The pull-out strength was significantly difference between commercially available pedicle screw (408.60 N) with square-thread conical pedicle screw (836.60 N) (p < 0.05). The square-thread conical-core group have the highest interface area (1486.21 mm2). The data comparison showed that the square-thread conical-core customized pedicle screw group has comparable insertion time and has better pull-out strength than commercially available pedicle screw.

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Comparison of Insertion Time, Pull-out Strength, and Screw-media Interface Area of Customized Pedicle Screw With Different Core and Thread Design Against Commercial Pedicle Screw

10.21203/rs.3.rs-429747/v1 ◽

2021 ◽

Author(s):

Rahadyan Magetsari ◽

Tedjo Rukmoyo ◽

Marda Ade Saputra ◽

Yudha Mathan Sakti

Keyword(s):

Pedicle Screw ◽

Pedicle Screws ◽

Insertion Time ◽

Control Group ◽

Interface Area ◽

Screw Design ◽

Pull Out ◽

Thread Diameter ◽

Screw Group ◽

Pull Out Strength

Abstract Objective: This research aimed to developing customized pedicle screw based on Indonesian vertebral anatomy and compare the insertion time, pull-out strength, and screw-media interface area of different screw design. We have developed 3 different types of pedicle screws (v-thread cylinder-core, square-thread cylinder-core and square-thread conical-core). The thread diameter was calculated from pedicle width of Indonesian population (6 mm). We used commercially available pedicle screw as control group (6.2 mm). Result: The insertion time were significantly difference between v-thread cylinder-core pedicle screw (22,94 s) with commercially available pedicle screw (15.86 s) (p<0.05). The pull-out strength was significantly difference between commercially available pedicle screw (408.60 N) with square-thread conical pedicle screw (836.60 N) (p<0.05). The square-thread conical-core group have the highest interface area (1486.21 mm2). The data comparison showed that the square-thread conical-core customized pedicle screw group has comparable insertion time and has better pull-out strength than commercially available pedicle screw.

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A Novel Technique for Measuring Pedicle Screw Forces In Situ

ASME 2008 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2008-192219 ◽

2008 ◽

Cited By ~ 1

Author(s):

Samuel Q. Tia ◽

Jennifer M. Buckley ◽

Thuc-Quyen Nguyen ◽

Jeffrey C. Lotz ◽

Shane Burch

Keyword(s):

Pedicle Screw ◽

Pedicle Screws ◽

Clinical Failure ◽

Strain Gages ◽

Destructive Testing ◽

Novel Technique ◽

Pull Out ◽

Pull Out Strength

Long posterior fusion constructs in the lumbar spine cause substantial posteriorly directed loading of the supporting pedicle screws, particularly during patient bending activities. Although there are numerous documented accounts of clinical failure at the pedicle screw-bone interface [1,2], the in situ pull-out strength of pedicle screws in long surgical constructs has not been characterized. Previous biomechanical studies have quantified pedicle screw pull-out force in cadaveric models through destructive testing or in nondestructive cases, through the use of custom-machined pedicle screws instrumented with strain gages [3–6]. However, these techniques involve altering screw geometry and may fail to properly simulate in vivo mechanical loading conditions. The goal of this study was to develop and validate a sensor system for measuring pedicle screw pull-out forces in long posterior constructs in situ during multi-segmental cadaveric testing.

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Correlation between the Computed Tomography Values of the Screw Path and Pedicle Screw Pullout Strength: An Experimental Study in Porcine Vertebrae

Asian Spine Journal ◽

10.31616/asj.2019.0170 ◽

2020 ◽

Vol 14 (3) ◽

pp. 265-272

Author(s):

Atsushi Ikeura ◽

Taketoshi Kushida ◽

Kenichi Oe ◽

Yoshihisa Kotani ◽

Muneharu Ando ◽

...

Keyword(s):

Computed Tomography ◽

Bone Mineral Density ◽

Pedicle Screw ◽

Bone Mineral ◽

Lumbar Vertebrae ◽

Pedicle Screws ◽

Mineral Density ◽

Screw Insertion ◽

Pull Out ◽

Pull Out Strength

Study Design: Biomechanical study.Purpose: To assess the correlation between the computed tomography (CT) values of the pedicle screw path and screw pull-out strength.Overview of Literature: The correlation between pedicle screw pull-out strength and bone mineral density has been well established. In addition, several reports have demonstrated a correlation between bone mineral density and CT values. However, no previous biomechanical studies investigated the correlation between CT values and pedicle screw pull-out strength.Methods: Sixty fresh-frozen lumbar vertebrae from 6-month-old pigs were used. Before screw insertion, the CT values of the screw path were obtained for each sample. Specimens were then randomly divided into three equal groups. Each group had one of three pedicle screws inserted: 4.0-mm LEGACY (4.0-LEG), 4.5-mm LEGACY (4.5-LEG), or 4.5-mm SOLERA (4.5-SOL) (all from Medtronic Sofamor Danek Inc., Memphis, TN, USA). Each screw had a consistent 30-mm thread length. Axial pull-out testing was performed at a rate of 1.0 mm/min. Correlations between the CT values and pedicle screw pull-out strength were evaluated using Pearson’s correlation coefficient analysis.Results: The correlation coefficients between the CT values of the screw path and pedicle screw pull-out strength for the 4.0-LEG, 4.5-LEG, and 4.5-SOL groups were 0.836 (p <0.001), 0.780 (p <0.001), and 0.873 (p <0.001), respectively. Greater CT values were associated with greater screw pull-out strength.Conclusions: The CT values of the screw path were strongly positively correlated with pedicle screw pull-out strength, regardless of the screw type and diameter, suggesting that the CT values could be clinically useful for predicting pedicle screw pull-out strength.

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The effect of cement augmentation on pedicle screw fixation under various load cases

Bone and Joint Research ◽

10.1302/2046-3758.1012.bjr-2020-0533.r1 ◽

2021 ◽

Vol 10 (12) ◽

pp. 797-806

Author(s):

Yan Chevalier ◽

Maiko Matsuura ◽

Sven Krüger ◽

Hannes Traxler ◽

Christoph Fleege† ◽

...

Keyword(s):

Pedicle Screw ◽

Bone Quality ◽

Pedicle Screws ◽

Bending Stiffness ◽

Cement Augmentation ◽

Fixation Strength ◽

Screw Design ◽

Pull Out ◽

Local Bone ◽

Significant Difference

Aims Anchorage of pedicle screw rod instrumentation in the elderly spine with poor bone quality remains challenging. Our study aims to evaluate how the screw bone anchorage is affected by screw design, bone quality, loading conditions, and cementing techniques. Methods Micro-finite element (µFE) models were created from micro-CT (μCT) scans of vertebrae implanted with two types of pedicle screws (L: Ennovate and R: S4). Simulations were conducted for a 10 mm radius region of interest (ROI) around each screw and for a full vertebra (FV) where different cementing scenarios were simulated around the screw tips. Stiffness was calculated in pull-out and anterior bending loads. Results Experimental pull-out strengths were excellently correlated to the µFE pull-out stiffness of the ROI (R2 > 0.87) and FV (R2 > 0.84) models. No significant difference due to screw design was observed. Cement augmentation increased pull-out stiffness by up to 94% and 48% for L and R screws, respectively, but only increased bending stiffness by up to 6.9% and 1.5%, respectively. Cementing involving only one screw tip resulted in lower stiffness increases in all tested screw designs and loading cases. The stiffening effect of cement augmentation on pull-out and bending stiffness was strongly and negatively correlated to local bone density around the screw (correlation coefficient ( R) = -0.95). Conclusion This combined experimental, µCT and µFE study showed that regional analyses may be sufficient to predict fixation strength in pull-out and that full analyses could show that cement augmentation around pedicle screws increased fixation stiffness in both pull-out and bending, especially for low-density bone. Cite this article: Bone Joint Res 2021;10(12):797–806.

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Influence of bone quality and pedicle screw design on the fixation strength during Axial Pull-out test: A 2D Axisymmetric FE study

10.1109/embc46164.2021.9629484 ◽

2021 ◽

Author(s):

Harikrishna Makaram ◽

Ramakrishnan Swaminathan

Keyword(s):

Pedicle Screw ◽

Bone Quality ◽

Fixation Strength ◽

Screw Design ◽

Pull Out

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Possible Usage of Cannulated Pedicle Screws without Cement Augmentation

Applied Bionics and Biomechanics ◽

10.1155/2014/984131 ◽

2014 ◽

Vol 11 (3) ◽

pp. 149-155 ◽

Cited By ~ 4

Author(s):

Teyfik Demir

Keyword(s):

Pedicle Screws ◽

Pedicle Screw Fixation ◽

Cement Augmentation ◽

Control Group ◽

Pullout Strength ◽

Screw Design ◽

Pullout Tests ◽

Pu Foam ◽

Common Problems ◽

Testing Protocols

Background: The use of pedicle screws is becoming increasingly popular for spinal surgery practice as the technology advances. Screw pullout due to bone quality and loading conditions is one of the most common problems observed after pedicle screw fixation. Several solutions were studied to prevent screw pullout. These can be investigated under three main categories: screw design, expandable screws and cement augmentation.Objective: This study aimed to investigate the pullout performance of cannulated screws without cement augmentation on synthetic foams.Methods: Artificial fusion process for PU is described and validated in our previous studies. For this study six newly designed cannulated pedicle screws were artificially fused to PU foam and pullout test were conducted according to ASTM F543 standard testing protocols.Results: According to the results of post-fusion pullout tests, worst performed cannulated screw design was S3H on healthy bone simulating PU foam. However, pullout strength of unilaterally three holes including (S3H) design was purchased with two times higher loads when compared to control group. Solid cored screws were purchased with 671 N where this value was 1450 N for S3H design.Conclusions: This study provided that using cannulated pedicle screws without cement augmentation for the cases with healthy bone can be a reliable alternative to classical screws. To the knowledge of the authors this is the first post-fusion study investigating cannulated pedicle screws without cement augmentation.

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Influence of novel design alteration of pedicle screw on pull-out strength: A finite element study

Journal of Orthopaedic Science ◽

10.1016/j.jos.2019.03.002 ◽

2020 ◽

Vol 25 (1) ◽

pp. 66-72 ◽

Cited By ~ 1

Author(s):

Shota Takenaka ◽

Takashi Kaito ◽

Ken Ishii ◽

Kota Watanabe ◽

Kei Watanabe ◽

...

Keyword(s):

Finite Element ◽

Pedicle Screw ◽

Finite Element Study ◽

Pull Out ◽

Novel Design ◽

Pull Out Strength ◽

Element Study

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Effectiveness of the Thoracic Pedicle Screw Placement Using the Virtual Surgical Training System: A Cadaver Study

Operative Neurosurgery ◽

10.1093/ons/opy030 ◽

2018 ◽

Vol 15 (6) ◽

pp. 677-685 ◽

Cited By ~ 6

Author(s):

Yang Hou ◽

Yanping Lin ◽

Jiangang Shi ◽

Huajiang Chen ◽

Wen Yuan

Keyword(s):

Pedicle Screw ◽

Surgical Training ◽

Pedicle Screws ◽

Cadaver Study ◽

Training System ◽

Screw Placement ◽

Control Group ◽

Pedicle Screw Placement ◽

Thoracic Pedicle Screw ◽

Screw Penetration

Abstract BACKGROUND The virtual simulation surgery has initially exhibited its promising potentials in neurosurgery training. OBJECTIVE To evaluate effectiveness of the Virtual Surgical Training System (VSTS) on novice residents placing thoracic pedicle screws in a cadaver study. METHODS A total of 10 inexperienced residents participated in this study and were randomly assigned to 2 groups. The group using VSTS to learn thoracic pedicle screw fixation was the simulation training (ST) group and the group receiving an introductory teaching session was the control group. Ten fresh adult spine specimens including 6 males and 4 females with a mean age of 58.5 yr (range: 33-72) were collected and randomly allocated to the 2 groups. After exposing anatomic structures of thoracic spine, the bilateral pedicle screw placement of T6-T12 was performed on each cadaver specimen. The postoperative computed tomography scan was performed on each spine specimen, and experienced observers independently reviewed the placement of the pedicle screws to assess the incidence of pedicle breach. RESULTS The screw penetration rates of the ST group (7.14%) was significantly lower in comparison to the control group (30%, P < .05). Statistically significant difference in acceptable rates of screws also occurred between the ST (100%) and control (92.86%) group (P < .05). In addition, the average screw penetration distance in control group (2.37 mm ± 0.23 mm) was significantly greater than ST group (1.23 mm ± 0.56 mm, P < .05). CONCLUSION The virtual reality surgical training of thoracic pedicle screw instrumentation effectively improves surgical performance of novice residents compared to those with traditional teaching method, and can help new beginners to master the surgical technique within shortest period of time.

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