Fatigue Testing of a Titanium Tapered Rod versus Two Rods Connected by a Parallel Connector across the Cervicothoracic Junction: A Biomechanical Study

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Ammar Qutub
Fahad Abduljabbar
Anas Nooh
Lorne Beckman
Lauren Bould
Thomas Steffen
Peter Jarzem

Abstract

This study compares the fatigue failure of a tapered titanium-rod construct against two connected titanium rods (domino construct) across the cervicothoracic junction. All testing was carried out in a simulated flexion-extension plane. The 3.5-mm/6.0-mm tapered titanium rod and the 3.5-mm titanium rod, connected to a 6.0-mm titanium rod with a connector, were compared for their fatigue failures. Six specimens of each construct were tested in a cantilever displacement control method using 6 different amplitudes. Each specimen was cycled to failure or to 2.5 million cycles (run out) at 10 Hz. Failure was defined as rod fracture. The domino construct reached the test limit of 2.5 million cycles at± 0.45 mm (72 N) but failed in all the other tested amplitudes. The tapered rod construct reached the test run out limit of 2.5 million cycles at higher amplitudes than the domino construct at ± 0.9 mm and failed in all the other tested amplitudes. The study showed that the tapered-rod construct across the cervicothoracic junction is more fatigue resistant than the domino construct.

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How to Cite
Qutub, A., Abduljabbar, F., Nooh, A., Beckman, L., Bould, L., Steffen, T., & Jarzem, P. (2020). Fatigue Testing of a Titanium Tapered Rod versus Two Rods Connected by a Parallel Connector across the Cervicothoracic Junction: A Biomechanical Study. Journal of King Abdulaziz University - Medical Sciences, 27(1), 5-11. https://doi.org/10.4197/Med.27-1.2
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Articles
Author Biographies

Ammar Qutub, King Abdulaziz University and McGill University Health Centre

Department of Orthopedic Surgery, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
McGill Scoliosis & Soine Centre, McGill University Health Centre, Montreal, Quebec, Canada

Fahad Abduljabbar, King Abdulaziz University and McGill University Health Centre

Department of Orthopedic Surgery, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
McGill Scoliosis & Soine Centre, McGill University Health Centre, Montreal, Quebec, Canada

Anas Nooh, King Abdulaziz University and McGill University Health Centre

Department of Orthopedic Surgery, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
McGill Scoliosis & Soine Centre, McGill University Health Centre, Montreal, Quebec, Canada

Lorne Beckman, McGill University Health Centre

Orthopaedic Research Laboratory, McGill University Health Centre, Montreal, Quebec, Canada

Lauren Bould, McGill University Health Centre

Orthopaedic Research Laboratory, McGill University Health Centre, Montreal, Quebec, Canada

Thomas Steffen, McGill University Health Centre

Orthopaedic Research Laboratory, McGill University Health Centre, Montreal, Quebec, Canada

Peter Jarzem, McGill University Health Centre

McGill Scoliosis & Soine Centre, McGill University Health Centre, Montreal, Quebec, Canada