Screw insertion torque as parameter to judge the fixation. Assessment of torque and pull-out strength in different bone densities and screw-pitches

Addevico, Francesco; Morandi, Massimo; Scaglione, Michelangelo; Solitro, Giovanni F.

doi:10.1016/j.clinbiomech.2019.12.004

Cited by 24 publications

(13 citation statements)

References 29 publications

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“…Indeed, no significant difference was found between tapered and straight 6 mm screws in terms of mean insertion torque, while the maximum insertion torque obtained with the most tapered screw was significantly different from the others. The influence of the screw pitch was previously investigated by other authors, obtaining different results: in some studies, the pitch influenced the insertion torque [16], while it was not significant in other investigations [8]. In this study, the importance of screw pitch was not highlighted, which could be caused by the fact that its influence also relies on bone quality [17].…”

Section: Quantitymentioning

confidence: 57%

“…The initial fixation of the screws can be assessed by evaluating the maximum torque during the insertion [1][2][3], which depends on numerous factors, including the bone mineral density, the design of the screw, and its dimensions [4][5][6][7]. Low insertional torque can cause poor compressive force between the plate and the bone [8]. On the other hand, excessive insertional torque can lead to the stripping of the screw, affecting its primary stability [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cortical bone screws constructive characteristics – A comparative study

Lugas¹,

Aloj²,

Santoro³

et al. 2021

Int. J. CMEM

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Section: Quantitymentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Cortical bone screws constructive characteristics – A comparative study

Lugas¹,

Aloj²,

Santoro³

et al. 2021

Int. J. CMEM

View full text Add to dashboard Cite

“…Similarly, Yamaguchi et al reported a greater insertion torque with double-lead dental implants [16]. For surgeons placing pedicle screws in clinical settings, the torque required to insert the screws is believed to be a good predictor of initial stability and pullout strength [17]. An in vitro biomechanical test by Jacob et al [13] showed that double-lead pedicle screws could reduce insertion time, but did not improve the pullout strength.…”

Section: Discussionmentioning

confidence: 99%

Cutting Flute and Thread Design on Self-Tapping Pedicle Screws Influence the Insertion Torque and Pullout Strength

Hsieh

Kuo

et al. 2022

Applied Sciences

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Self-tapping screws are commonly used in trauma and maxillofacial surgery and are increasingly used for pedicle screw insertions. In order to evaluate how the quantity and length of cutting flutes on self-tapping pedicle screws affect the insertion torque and pullout strength, eight different self-tapping pedicle screw designs were evaluated. All screws had a threaded length of 35 mm and featured variations in the number of leads, as well as the length and quantity of cutting flutes. Five samples of each design were inserted into pre-drilled, untapped holes (ø2.7 mm, length 35 mm) in sawbone blocks of density 20 PCF. The insertion torque and pullout strength were measured according to ASTM F543. The results showed that screws with a longer cutting flute of 9.5 mm had a lower mean maximum insertion torque than screws with shorter 2.9 mm cutting flutes. Pedicle screws with a double-lead thread design had a greater insertion torque than their single-lead counterparts, and the use of three cutting flutes produced a lower torque than two cutting flutes. The results demonstrated a greater pullout strength in screws with a single-lead thread rather than a double-lead, three cutting flutes instead of two, and a longer length for the cutting flute. In conclusion, to provide immediate stability and reduce the surgical insertion time, a single-lead, self-tapping pedicle screw incorporating three long cutting flutes is recommended because of the significantly greater pullout strength. This design could also reduce the risk of implant loosening in comparison to double-lead, self-tapping pedicle screw designs.

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“…The four remaining configurations were obtained by tightening a first screw past the compression phase (phase 4 of Figure 3 ) until a drop from the torque peak value was observed [ 16 , 17 , 18 , 19 ].…”

Section: Methodsmentioning

confidence: 99%

Salvaging Pull-Out Strength in a Previously Stripped Screw Site: A Comparison of Three Rescue Techniques

Addevico

Solitro

Morandi

2021

JFMK

Self Cite

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Screw stripping during bone fixation is a common occurrence during operations that results in decreased holding capacity and bone healing. We aimed to evaluate the rescue of the stripped screw site using screws of different dimensions. Five screw configurations were tested on cadaveric specimens for pull-out strength (POS). The configurations included a control screw tightened without stripping, a configuration voluntarily stripped and left in place, and three more configurations in which the stripped screws were replaced by a different screw with either increased overall length, diameter, or thread length. Each configuration was tested five times, with each screw tested once. The POS of the control screw, measured to be 153.6 ± 27 N, was higher than the POS measured after stripping and leaving the screw in place (57.1 ± 18 N, p = 0.001). The replacement of the stripped screw resulted in a POS of 158.4 ± 64 N for the screw of larger diameter, while the screws of the same diameter but increased length or those with extended thread length yielded POS values of 138.4 ± 42 and 185.7 ± 48 N, respectively. Screw stripping is a frequent intraoperative complication that, according to our findings, cannot be addressed by leaving the screw in place. The holding capacity of a stripped screw implanted in cancellous bone can successfully be restored with a different screw of either larger diameter, longer length, or extended thread length.

show abstract

Screw insertion torque as parameter to judge the fixation. Assessment of torque and pull-out strength in different bone densities and screw-pitches

Cited by 24 publications

References 29 publications

Cortical bone screws constructive characteristics – A comparative study

Cortical bone screws constructive characteristics – A comparative study

Cutting Flute and Thread Design on Self-Tapping Pedicle Screws Influence the Insertion Torque and Pullout Strength

Salvaging Pull-Out Strength in a Previously Stripped Screw Site: A Comparison of Three Rescue Techniques

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