Skip to main content
Key Specialties
Cardiology Diabetology Endocrinology Gastroenterology Geriatrics and Gerontology Gynecology and Obstetrics Hematology Infectious Disease Internal Medicine Nephrology Neurology Oncology Pediatrics Respiratory Medicine Rheumatology Surgery
Congress Coverage
2024 ACC Congress 2023 ESMO Congress 2023 EASD Congress 2023 ERS Congress 2023 ESC Congress
Clinical Collections
Advances in Alzheimer’s

At a glance: The STEP trials

A round-up of the STEP phase 3 clinical trials evaluating semaglutide for weight loss in people with overweight or obesity.
ADVANCED SEARCH
Log in
Top
Scoliosis and Spinal Disorders
Published in: Scoliosis and Spinal Disorders 1/2015

Open Access 01-12-2015 | Research

Axial pullout strength comparison of different screw designs: fenestrated screw, dual outer diameter screw and standard pedicle screw

Authors: Evangelos Christodoulou, Suresh Chinthakunta, Divya Reddy, Saif Khalil, Thomas Apostolou, Philipp Drees, Konstantinos Kafchitsas

Published in: Scoliosis and Spinal Disorders | Issue 1/2015

Login to get access

Abstract

Background

The pullout strength of pedicle screws is influenced by many factors, including diameter of the screws, implant design, and augmentation with bone cement such as PMMA. In the present study, the pullout strength of an innovative fenestrated screw augmented with PMMA was investigated and was compared to unaugmented fenestrated, standard and dual outer diameter screw.

Methods

Twenty four thoracolumbar vertebrae (T10-L5, age 60 to 70 years) from three cadavers were implanted with the four different pedicle screws. Twelve screws of each type were instrumented into either left or right pedicle with standard screw paired with unaugmented and dual outer diameter screw paired with augmented fenestrated screw in any given vertebra. Axial pullout testing was conducted at a rate of 5 mm/min. Force to failure (Newtons) for each pedicle screw was recorded.

Results

The augmented fenestrated screws had the highest pullout strength, which represented an average increase of 149%, 141%, and 78% in comparison to unaugmented, standard, and dual outer diameter screws, respectively. Pullout strength of unaugmented screws was comparable to that of standard screws, however it was significantly lower than dual outer diameter screws.

Conclusions

Fenestrated screws augmented with PMMA improve the fixation strength and result in significantly higher pullout strength compared to dual outer diameter, standard and unaugmented fenestrated screws. Screws with dual outer diameter provided enhanced bone-screw purchase and may be considered as an alternative technique to increase the bone-screw interface in cases where augmentation using bone cement is not feasible. Unaugmented screws can be left in the pedicle even without cement and provide similar pullout strength to standard screws.
Literature
1.
Abshire BB, McLain RF, Valdevit A, Kambic HE. Characteristics of pullout failure in conical and cylindrical pedicle screws after full insertion and back-out. Spine J. 2001;1:408–14.CrossRefPubMed
2.
Rohmiller MT, Schwalm D, Glattes RC, Elalayli TG, Spengler DM. Evaluation of calcium sulfate paste for augmentation of lumbar pedicle screw pullout strength. Spine J. 2002;2:255–60.CrossRefPubMed
3.
Cook SD, Salkeld SL, Stanley T, Faciane A, Miller SD. Biomechanical study of pedicle screw fixation in severely osteoporotic bone. Spine J. 2004;4:402–8.CrossRefPubMed
4.
Liu D, Wu ZX, Pan XM, Fu SC, Gao MX, Shi L, et al. Biomechanical comparison of different techniques in primary spinal surgery in osteoporotic cadaveric lumbar vertebrae: expansive pedicle screw versus polymethylmethacrylate-augmented pedicle screw. Arch Orthop Trauma Surg. 2011;131:1227–32.CrossRefPubMed
5.
Yazu M, Kin A, Kosaka R, Kinoshita M, Abe M. Efficacy of novel-concept pedicle screw fixation augmented with calcium phosphate cement in the osteoporotic spine. J Orthop Sci. 2005;10(1):56–61.CrossRefPubMed
6.
Santoni BG, Hynes RA, McGilvray KC, Rodriguez-Canessa G, Lyons AS, Henson MA, et al. Cortical bone trajectory for lumbar pedicle screws. Spine J. 2009;9(5):366–73. doi: 10.1016/j.spinee.2008.07.008. Epub 2008 Sep 14.CrossRefPubMed
7.
Frankel BM, D'Agostino S, Wang C. A biomechanical 350 cadaveric analysis of polymethylmethacrylate-augmented pedicle screw fixation. J Neurosurg Spine. 2007;7:47–53.CrossRefPubMed
8.
Burval DJ, McLain RF, Milks R, Inceoglu S. Primary pedicle screw augmentation in osteoporotic lumbar vertebrae: biomechanical analysis of pedicle fixation strength. Spine. 2007;32:1077–83.CrossRefPubMed
9.
Kiner DW, Wybo CD, Sterba W, Yeni YN, Bartol SW, Vaidya R. Biomechanical analysis of different techniques in revision spinal instrumentation: larger diameter screws versus cement augmentation. Spine. 2008;33:2618–22.CrossRefPubMed
10.
Wittenberg RH, Lee KS, Shea M, White 3rd AA, Hayes WC. Effect of screw diameter, insertion technique, and bone cement augmentation of pedicular screw fixation strength. Clin Orthop Relat Res. 1993;296:278–87.PubMed
11.
Polly Jr DW, Orchowski JR, Ellenbogen RG. Revision pedicle screws: bigger, longer shims–what is best? Spine. 1998;23:1374–9.CrossRefPubMed
12.
Cho W, Wu C, Erkan S, Kang MM, Mehbod AA, Transfeldt EE. The effect on the pullout strength by the timing of pedicle screw insertion after calcium phosphate cement injection. J Spinal Disord Tech. 2011;24:116–20.CrossRefPubMed
13.
Barber JW, Boden SD, Ganey T, Hutton WC. Biomechanical study of lumbar pedicle screws: does convergence affect axial pullout strength? J Spinal Disord. 1998;11:215–20.CrossRefPubMed
14.
Felsenberg D, Gowin W. Bone densitometry by dual energy methods. Radiochemistry. 1999;39(3):186–93.
15.
Blattert T, Weckbach A. Kalziumphosphat vs. Polymethylmethacrylat. Erste Ergebnisse einer prospektiven, randomisierten, klinischen Vergleichsstudie zur perkutanen Ballonkyphoplastie. Trauma Berufskrankheit. 2004;6:273–8.CrossRef
16.
Chang MC, Liu CL, Chen TH. Polymethylmethacrylate augmentation of pedicle screw for osteoporotic spinal surgery: a novel technique. Spine. 2008;33(10):E317–24.CrossRefPubMed
17.
Bullmann V, Schmoelz W, Richter M, Grathwohl C, Schulte TL. Revision of cannulated and perforated cement-augmented pedicle screws: a biomechanical study in human cadavers. Spine. 2010;35(19):E932-9.CrossRefPubMed
18.
Sterba W, Kim DG, Fyhrie DP, Yeni YN, Vaidya R. Biomechanical analysis of differing pedicle screw insertion angles. Clin Biomech (Bristol, Avon). 2007;22:385–91.CrossRef
19.
Belkoff SM, Molloy S. Temperature measurement during polymerization of polymethylmethacrylate cement used for vertebroplasty. Spine. 2003;28:1555–9.PubMed
20.
Erkan S, Hsu B, Wu C, Mehbod AA, Perl J, Transfeldt EE. Alignment of pedicle screws with pilot holes: can tapping improve screw trajectory in thoracic spines? Eur Spine J. 2010;19(1):71–7.CrossRefPubMed
21.
Chapman JR, Harrington RM, Lee KM, Anderson PA, Tencer AF, Kowalski DJ. Factors affecting the pullout strength of cancellous bone screws. Biomech Eng. 1996;118(3):391–8.CrossRef
22.
Karataglis D, Kapetanos G, Lontos A, Christodoulou A, Christoforides J, Pournaras J. The role of the dorsal vertebral cortex in the stability of transpedicular screws: a biomechanical study in human cadaveric vertebrae. J Bone Joint Surg Br Vol. 2006;88(5):692–5.CrossRef
23.
Hirano T, Hasegawa K, Washio T, Hara T, Takahashi H. Fracture risk during pedicle screw insertion in osteoporotic spine. J Spinal Disord. 1998;11(6):493–7.CrossRefPubMed
24.
Kumano K, Hirabayashi S, Ogawa Y, Aota Y. Pedicle screws and bone mineral density. Spine. 1994;19(10):1157–61.CrossRefPubMed
25.
Hirano T, Hasegawa K, Takahashi HE, Uchiyama S, Hara T, Washio T, et al. Structural characteristics of the pedicle and its role in screw stability. Spine. 1997;22(21):2504–9. discussion 10.CrossRefPubMed
Metadata
Title
Axial pullout strength comparison of different screw designs: fenestrated screw, dual outer diameter screw and standard pedicle screw
Authors
Evangelos Christodoulou
Suresh Chinthakunta
Divya Reddy
Saif Khalil
Thomas Apostolou
Philipp Drees
Konstantinos Kafchitsas
Publication date
01-12-2015
Publisher
BioMed Central
Published in
Scoliosis and Spinal Disorders / Issue 1/2015
Electronic ISSN: 2397-1789
DOI
https://doi.org/10.1186/s13013-015-0039-6

Other articles of this Issue 1/2015

Scoliosis and Spinal Disorders 1/2015 Go to the issue

Research

Relationship between bone density and bone metabolism in adolescent idiopathic scoliosis

Research

Gravity-induced coronal plane joint moments in adolescent idiopathic scoliosis

Retraction Note

Retraction Note: Relationship between bone density and bone metabolism in adolescent idiopathic scoliosis

Research

Fasting total ghrelin levels are increased in patients with adolescent idiopathic scoliosis

Review

“Bone-οn-Bone” surgical reconstruction of moderate severity, flexible single curve adolescent idiopathic scoliosis: continuing improvements of the technique and results in three scoliosis centers after almost twenty years of use

Research

Laser triangulation measurements of scoliotic spine curvatures