Pull out Strength of Dual Outer Diameter Pedicle Screws Compared to Uncemented and Cemented Standard Pedicle Screws: A Biomechanical <i>in vitro</i> Study

Lorenz, Andrea; Leichtle, Carmen; Frantz, Sandra; Bumann, Marte; Tsiflikas, Ilias; Shiozawa, Thomas; Leichtle, Ulf

doi:10.1111/os.12322

Cited by 7 publications

(2 citation statements)

References 36 publications

(63 reference statements)

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“…Various studies have demonstrated that BMD is a critical factor in determining the pull-out force 27,28 . However, this study has highlighted the fact that BMD has a weak or no correlation with the pull-out force 13 .…”

Section: Bmd and Micro-ct Scanningmentioning

confidence: 99%

Comparison of the Pull‐Out Strength between a Novel Micro‐Dynamic Pedicle Screw and a Traditional Pedicle Screw in Lumbar Spine

Qian

Chen

et al. 2020

Orthopaedic Surgery

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Objective This study aimed to investigate the strength of a novel micro‐dynamic pedicle screw by comparing it to the traditional pedicle screw. Methods Forty‐five lumbar vertebrae received a traditional pedicle screw on one side and a micro‐dynamic pedicle screw on the other side as follows (traditional group vs micro‐dynamic group): 15 vertebrae underwent instant pull‐out testing; 15 vertebrae underwent 5000‐cyclic fatigue loading testing; and 15 vertebrae underwent 10,000‐cyclic fatigue loading testing and micro‐computed tomography (micro‐CT) scanning. The peek pull‐out force and normalized peek pull‐out force after instant pull‐out testing, 5000‐cyclic and 10,000‐cyclic fatigue loading testing were recorded to estimate the resistance of two types of screws. Bone mineral density was recorded to investigate the strength of the different screws in osteoporotic patients. And the semidiameter of the screw insertion area on micro‐CT images after fatigue were compared to describe the performance between screw and bone surface. Results The bone mineral density showed a weak correlation with peek pull‐out force (r = 0.252, P = 0.024). The peek pull‐out force of traditional pedicle screw after 10,000‐cyclic fatigue loading were smaller than that of instant pull‐out test in both osteoporotic (P = 0.017) and healthy group (P = 0.029), the peek pull‐out force of micro‐dynamic pedicle screw after 10,000‐cyclic fatigue loading was smaller than that in instant pull‐out test in osteoporotic group (P = 0.033), but no significant difference in healthy group (P = 0.853). The peek pull‐out force in traditional group and micro‐dynamic group underwent instant pull‐out testing (P = 0.485), and pull‐out testing after 5000‐cyclic fatigue loading testing (P = 0.184) did not show significant difference. However, the peek pull‐out force in micro‐dynamic group underwent pull‐test after 10,000‐cyclic fatigue loading testing was significantly greater than that measured in traditional group (P = 0.005). The normalized peek pull‐out force of traditional groups underwent instant pull‐out testing, pull‐out test after 5000‐cyclic and 10,000‐cyclic fatigue loading testing significantly decreased as the number of cycles increased (P < 0.001); meanwhile, the normalized peek pull‐out force of micro‐dynamic groups remained consistent regardless of the number of cycles (P = 0.133). The semidiameter after the fatigue loading test of the traditional screw insertion area was significantly larger than that of the micro‐dynamic screw insertion area (P = 0.013). Conclusion The novel micro‐dynamic pedicle screw provides stronger fixation stability in high‐cyclic fatigue loading and non‐osteoporotic patients versus the traditional pedicle screw, but similar resistance in low‐cycle fatigue testing and osteoporotic group vs the traditional pedicle screw.

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Section: Bmd and Micro-ct Scanningmentioning

confidence: 99%

Comparison of the Pull‐Out Strength between a Novel Micro‐Dynamic Pedicle Screw and a Traditional Pedicle Screw in Lumbar Spine

Qian

Chen

et al. 2020

Orthopaedic Surgery

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“…While the insertion of thicker and longer screws is a frequently applied solution for screw loosening noticed during the operation, cement augmentation is also a good salvage method, especially in the osteoporotic spine. 2 , 3 , 5 Cement application yields the best screw pullout force among other salvage methods. However, cement augmentation, especially in the thoracic region, has been shown to be associated with an increased risk of pulmonary cement embolism.…”

Section: Introductionmentioning

confidence: 99%

Intraoperative lateral wall breach simulation in the cadaveric spine and the impact of thread designs of screws on pullout strength in the osteoporotic thoracic vertebrae: A biomechanical study in human cadavers

Kaya,

Ozkunt,

Sungur

et al. 2024

Acta Orthopaedica et Traumatologica Turcica

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Objective: This study aimed (1) to simulate pedicle screw pullout after intraoperative external wall perforation and (2) to assess restoration strength with different thread designs in the pedicle screw instrumentation for osteoporotic thoracic vertebrae. Methods: Twenty fresh-frozen human cadaveric thoracic vertebra bodies were prepared and divided into 4 groups: group 1, 5.5 mm × 45 mm polyaxial single thread pedicle screws (PASTS); group 2, after wall injury 5.5 mm × 45 mm PASTS; group 3, 6.5 mm × 45 mm PASTS after wall injury; and group 4: 6.5 mm × 45 mm polyaxial mixed-threaded screws after wall injury. While group 1 was the control group, groups 2, 3, and 4 were used as study groups after the lateral wall breach. All prepared screw units were placed on a universal pullout measurement testing device. Results: The mean bone mineral density for 20 thoracic vertebrae was 0.57 ± 0.12 g/cm 2 (range 0.53-0.6 g/cm 2 ). The mean pullout strength was 474.90 Newtons (N) for group 1, 412.85 N for group 2, 475.4 N for group 3, and 630.74N for group 4. The lateral wall breach caused a 14.1 % decrease in average pullout strength compared with the initial screw pullout. Mixed (double)-threaded screws increased pullout strength compared to 6.5 mm screws ( P = .036) Conclusion: Using a 1 mm thicker polyaxial pedicle screw or mixed (double)-threaded pedicle screw seems to increase pullout strength; however, this was statistically significant only for group 4. In the thoracic spine, the redirection possibility of the pedicle screw is limited, and augmentation with cement will not be appropriate due to the risk of wall injury-related leakage. Therefore, care should be taken to avoid violating the lateral cortex by using appropriate pedicle entry points and trajectories.

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Biomechanical Comparison of Pull-out Strength of Different Cementation and Pedicle Screw Placement Techniques in a Calf Spine Model

Akgül

Korkmaz

Pehlivanoğlu³

et al. 2020

IJOO

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Pull out Strength of Dual Outer Diameter Pedicle Screws Compared to Uncemented and Cemented Standard Pedicle Screws: A Biomechanical in vitro Study

Cited by 7 publications

References 36 publications

Comparison of the Pull‐Out Strength between a Novel Micro‐Dynamic Pedicle Screw and a Traditional Pedicle Screw in Lumbar Spine

Comparison of the Pull‐Out Strength between a Novel Micro‐Dynamic Pedicle Screw and a Traditional Pedicle Screw in Lumbar Spine

Intraoperative lateral wall breach simulation in the cadaveric spine and the impact of thread designs of screws on pullout strength in the osteoporotic thoracic vertebrae: A biomechanical study in human cadavers

Biomechanical Comparison of Pull-out Strength of Different Cementation and Pedicle Screw Placement Techniques in a Calf Spine Model

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