Pedro Berjano1, Juan Francisco Blanco2, Diego Rendon3, Jorge Hugo Villafañe4, David Pescador5, Carlos Manuel Atienza6. 1. IRCCS Istituto Ortopedico Galeazzi, Milan, Italy. pberjano@gmail.com. 2. Spine Unit, University Hospital of Salamanca, Salamanca, Spain. juanfblanco@telefonica.net. 3. Department of Orthopedic Surgery, University Hospital of Salamanca, Salamanca, Spain. diegor07@hotmail.com. 4. IRCCS Don Gnocchi Foundation, Milan, Italy. mail@villafane.it. 5. Spine Unit, University Hospital of Salamanca, Salamanca, Spain. pesc21@yahoo.es. 6. Instituto de Biomecánica de Valencia, Universidad Politécnica de Valencia, Valencia, Spain. carlos.atienza@ibv.upv.es.
Abstract
PURPOSE: To assess, with finite element analysis and an in vitro biomechanical study in cadaver, whether the implementation of an anterior interbody cage made of hedrocel with nitinol shape memory staples in compression increases the stiffness of the stand-alone interbody cage and to compare these constructs' stiffness to other constructs common in clinical practice. METHODS: A biomechanical study with a finite element analysis and cadaveric testing assessed the stiffness of different fixation modes for the L4-L5 functional spinal unit: intact spine, destabilized spine with discectomy, posterior pedicle-screw fixation, anterior stand-alone interbody cage, anterior interbody cage with bilateral pedicle screws and anterior interbody cage with two shape memory staples in compression. These modalities of vertebral fixation were compared in four loading modes (flexion, extension, lateral bending, and axial rotation). RESULTS: The L4-L5 spinal unit with an anterior interbody cage and two staples was stiffer than the stand-alone cage. The construct stiffness was similar to that of a model of posterior pedicular stabilization. The stiffness was lower than that of the anterior cage plus bilateral pedicle-screw fixation. CONCLUSION: The use of an anterior interbody implant with shape memory staples in compression may be an alternative to isolated posterior fixation and to anterior isolated implants, with increased stiffness.
PURPOSE: To assess, with finite element analysis and an in vitro biomechanical study in cadaver, whether the implementation of an anterior interbody cage made of hedrocel with nitinol shape memory staples in compression increases the stiffness of the stand-alone interbody cage and to compare these constructs' stiffness to other constructs common in clinical practice. METHODS: A biomechanical study with a finite element analysis and cadaveric testing assessed the stiffness of different fixation modes for the L4-L5 functional spinal unit: intact spine, destabilized spine with discectomy, posterior pedicle-screw fixation, anterior stand-alone interbody cage, anterior interbody cage with bilateral pedicle screws and anterior interbody cage with two shape memory staples in compression. These modalities of vertebral fixation were compared in four loading modes (flexion, extension, lateral bending, and axial rotation). RESULTS: The L4-L5 spinal unit with an anterior interbody cage and two staples was stiffer than the stand-alone cage. The construct stiffness was similar to that of a model of posterior pedicular stabilization. The stiffness was lower than that of the anterior cage plus bilateral pedicle-screw fixation. CONCLUSION: The use of an anterior interbody implant with shape memory staples in compression may be an alternative to isolated posterior fixation and to anterior isolated implants, with increased stiffness.
Authors: Randal R Betz; John Kim; Linda P D'Andrea; M J Mulcahey; Rohinton K Balsara; David H Clements Journal: Spine (Phila Pa 1976) Date: 2003-10-15 Impact factor: 3.468
Authors: Pedro Berjano; Ming Xu; Marco Damilano; Thomas Scholl; Claudio Lamartina; Michael Jekir; Fabio Galbusera Journal: Eur Spine J Date: 2019-05-25 Impact factor: 3.134
Authors: Amparo Vanaclocha-Saiz; Vicente Vanaclocha; Carlos M Atienza; Pablo Clavel; Pablo Jorda-Gomez; Carlos Barrios; Leyre Vanaclocha Journal: ACS Appl Bio Mater Date: 2021-12-14