An Improved Testing Protocol for Evaluating Anterior Spinal Instrumentation Using Graft Loads in a Single-Level Cervical Discectomy or Corpectomy Model

2002 ◽  
Author(s):  
Denis J. DiAngelo ◽  
Geza Osztheimer ◽  
Kevin T. Foley
Keyword(s):  
Fatigue Testing ◽  
Spinal Instrumentation ◽  
Endurance Performance ◽  
Test Method ◽  
Destructive Testing ◽  
Spinal Implant ◽  
Single Level ◽  
Testing Protocol ◽  
American Society ◽  
Anterior Spinal Instrumentation

Anterior cervical instrumentation used in discectomy or corpectomy graft fusion should restore the mechanical integrity of the operated spine and decrease graft complications. For fusion to occur, the spinal instrumentation must load-share with the interbody graft. Recent design changes in anterior cervical plates (ACP) aim to allow motion across the fusion site and load share with the graft [1]. However, existing American Society for Testing and Materials (ASTM) standards (F1717-96) for static and fatigue testing of spinal implant constructs in a corpectomy model do not include an interbody graft in the test method [2]. The objective of this study was to develop a non-destructive testing protocol and apparatus to rank the static and low-endurance performance of ACP instrumentation in single-level discectomy and corpectomy graft-plate models.

Effects of Anterior Spinal Instrumentation on Single-Level Cervical Graft Mechanics

2001 ◽  
Author(s):  
Denis J. DiAngelo ◽  
Weiqiang Liu ◽  
Brian P. Kelly ◽  
Kevin T. Foley
Keyword(s):  
Spinal Instrumentation ◽  
Single Level ◽  
Mechanical Integrity ◽  
Spinal Disc ◽  
Injured Region ◽  
Multi Level ◽  
Cervical Plate ◽  
Anterior Spinal Instrumentation ◽  
Anterior Cervical Plate ◽  
Flexion And Extension

Abstract Anterior cervical discectomy with or without graft fusion is an acceptable surgical method for the treatment of cervical spondylosis or other spinal disc diseases. A graft-alone or graft with supplemental spinal instrumentation may be used to immobilize the operated/injured region to promote bony fusion. Graft fusion with instrumentation is intended to restore the mechanical integrity of the operated spine and decrease graft complications. Although the surgical procedure should restore the mechanical integrity of the operated spine, little is known of the load-sharing mechanics of single-level grafted constructs. We have previously shown that anterior instrumentation reverses the loading mechanics of a multi-level cervical strut-graft tested under physiologic flexion and extension conditions (DiAngelo et al., 2000). We hypothesize that a single-level anterior cervical plate will function in a similar manner. That is, a single-level anterior cervical plate will reverse the loads on the graft by loading the graft in extension and unloading the graft in flexion. We also hypothesize that a graft-alone construct does not provide adequate stabilization comparable to that of the graft-plated condition tested in flexion and extension. The objective of the study was to determine the biomechanical stability of four different spine conditions tested under physiologic flexion and extension conditions. They included the harvested, discectomized, graft-alone, and graft with single-level anterior cervical plate.

CDH: preliminary report on a new anterior spinal instrumentation

1995 ◽  
Vol 4 (3) ◽  
pp. 194-199 ◽  
Author(s):  
C. Hopf ◽  
P. Eysel ◽  
J. Dubousset
Keyword(s):  
Preliminary Report ◽  
Spinal Instrumentation ◽  
Anterior Spinal Instrumentation

scholarly journals The Biological Effects of Combining Metals in a Posterior Spinal Implant: In Vivo Model Development Report of the First Two Cases

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Christine L. Farnsworth ◽  
Peter O. Newton ◽  
Eric Breisch ◽  
Michael T. Rohmiller ◽  
Jung Ryul Kim ◽  
...  
Keyword(s):  
Galvanic Corrosion ◽  
Biological Effects ◽  
Model Development ◽  
Spinal Instrumentation ◽  
Pedicle Screws ◽  
Tissue Response ◽  
In Vivo Model ◽  
Particle Count ◽  
Spinal Implant

Study Design. Combinations of metal implants (stainless steel (SS), titanium (Ti), and cobalt chrome (CC)) were placed in porcine spines. After 12 months, tissue response and implant corrosion were compared between mixed and single metal junctions. Objective. Model development and an attempt to determine any detriment of combining different metals in posterior spinal instrumentation. Methods. Yucatan mini-pigs underwent instrumentation over five unfused lumbar levels. A SS rod and a Ti rod were secured with Ti and SS pedicle screws, SS and Ti crosslinks, SS and CC sublaminar wires, and Ti sublaminar cable. The resulting 4 SS/SS, 3 Ti/Ti, and 11 connections between dissimilar metals per animal were studied after 12 months using radiographs, gross observation, and histology (foreign body reaction (FBR), metal particle count, and inflammation analyzed). Results. Two animals had constructs in place for 12 months with no complications. Histology of tissue over SS/SS connections demonstrated 11.1 ± 7.6 FBR cells, 2.1 ± 1.7 metal particles, and moderate to extensive inflammation. Ti/Ti tissue showed 6.3 ± 3.8 FBR cells, 5.2 ± 6.7 particles, and no to extensive inflammation (83% extensive). Tissue over mixed components had 14.1 ± 12.6 FBR cells and 13.4 ± 27.8 particles. Samples surrounding wires/cables versus other combinations demonstrated FBR (12.4 ± 13.5 versus 12.0 ± 9.6 cells, P = 0.96), particles (19.8 ± 32.6 versus 4.3 ± 12.7, P = 0.24), and inflammation (50% versus 75% extensive, P = 0.12). Conclusions. A nonfusion model was developed to study corrosion and analyze biological responses. Although no statistical differences were found in overlying tissue response to single versus mixed metal combinations, galvanic corrosion between differing metals is not ruled out. This pilot study supports further investigation to answer concerns when mixing metals in spinal constructs.

scholarly journals Fatigue Strength Analysis of S34MnV Steel by Accelerated Staircase Test

2020 ◽  
Vol 10 (1) ◽  
pp. 394-400 ◽  
Author(s):  
I. M. W. Ekaputra ◽  
Rando Tungga Dewa ◽  
Gunawan Dwi Haryadi ◽  
Seon Jin Kim
Keyword(s):  
Standard Deviation ◽  
Fatigue Strength ◽  
Fatigue Limit ◽  
Fatigue Testing ◽  
Reliability Estimation ◽  
Test Method ◽  
Strength Analysis ◽  
Staircase Method ◽  
Staircase Test ◽  
Number Of Cycles

AbstractThis paper presents the reliability estimation of fatigue strength of the material used for crank throw components. The material used for crank throw components is forged S34MnV steel and subsequently heat-treated by normalising and tempering. High cycle fatigue testing under fully reversed cycling (R = −1) was performed to determine the fatigue limit of the material. The staircase test method is used to obtain accurate values of the mean fatigue limit stress until a number of cycles up to 1E7 cycles. Subsequently, the fatigue test results depend strongly on the stress step and are evaluated by the Dixon-Mood formula. The values of mean fatigue strength and standard deviation predicted by the staircase method are 282 MPa and 10.6MPa, respectively. Finally, the reliability of the design fatigue strength in some selected probability of failure is calculated. Results indicate that the fatigue strength determined from accelerated staircase test is consistent with conventional fatigue testing. Furthermore, the proposed method can be applied for the determination of fatigue strength and standard deviation for design optimisation of S34MnV steel.

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