Many conflicting studies have been performed evaluating the effects of sterilization and storage treatments on the mechanical properties of allograft bone. In the current study, four right and left matched, sterile, deep-frozen, tibial pairs from human donors with an average age of 32 years were tested. One tibia from each pair served as a matched control for the opposite side. Each tibia was cut into four equal segments. One segment of each tibia underwent no treatment; the other three underwent one of the following treatments: irradiation, freeze drying, or ethylene oxide (ETO). Screw pullout tests were performed using four 3.5-mm cortical screws per segment. Sixteen screw pullout tests were performed for each allograft treatment. The freeze-dried specimens required significantly less force for screw pullout. The screw pullout force for the irradiated specimens and the ETO specimens did not significantly differ from their controls. These results indicate that freeze drying affected screw pullout strength. This method of processing should be questioned for structural allografts in which screw fixation is mandatory. The use of irradiation or ETO for sterilization may not have an adverse effect on screw pullout strength.
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Cureus
November 2024
Aerospace Engineering, Universiti Putra Malaysia, Kuala Lumpur, MYS.
Introduction Spinal fusion surgery with pedicle screws is commonly performed to stabilize the spine of osteoporotic patients. However, securing a strong screw fixation in osteoporotic bone presents significant challenges due to the reduced bone density. This study aimed to compare the biomechanical performance in an osteoporotic bone model of pedicle screws inserted using two different techniques, the Jamshidi needle technique and the pedicle probe technique, as well as the influence of tapping on both these techniques.
View Article and Find Full Text PDFPLoS One
December 2024
Bio-Inspired Technology Group, Faculty of Mechanical Engineering, Department of BioMechanical Engineering, Delft University of Technology, Delft, The Netherlands.
Pedicle screws have long been established as the gold standard for spinal bone fixation. However, their fixation strength can be compromised in cases of low bone density, particularly in osteoporotic bone, due to the reliance on a micro-shape lock between the screw thread and the surrounding bone. To address this challenge, we propose augmenting conventional pedicles screws with a curved compliant anchor.
View Article and Find Full Text PDFHeliyon
February 2024
Department of Life, Health and Environmental Sciences, Postgraduate School of Orthodontics, Università degli Studi dell'Aquila, Via Piazzale Salvatore Tommasi 1, Abruzzo, L'Aquila 67100, Italy.
Objective: This paper analyses the mechanical response of mini-implants under pull-out, push-in, and shear forces.
Materials And Methods: The authors have devised a specialized testing apparatus, using a universal testing machine, for the mechanical characterisation of orthodontic mini-implants (OMI) installed in pig hard palate. The experimental investigation encompasses seven screw types, each subjected to pull-out, push-in, and shear forces.
Orthop Traumatol Surg Res
December 2024
Aix-Marseille Université, APHM, CNRS, ISM, CHU Timone, Service de Chirurgie Orthopédique et Vertébrale, 264 rue Saint-Pierre, 13005 Marseille, France. Electronic address:
Ann Biomed Eng
December 2024
Luzhou Key Laboratory of Orthopedic Disorders, Department of Orthopedics, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, No. 182, Chunhui Road, Longmatan District, Luzhou, 646000, Sichuan, P.R. China.
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