scholarly journals An In Vitro Biomechanical Evaluation of a Lateral Lumbar Interbody Fusion Device With Integrated Lateral Modular Plate Fixation

2020 ◽  
pp. 219256822090561
Author(s):  
Ryan DenHaese ◽  
Anup Gandhi ◽  
Chris Ferry ◽  
Sam Farmer ◽  
Randall Porter
Keyword(s):  
Range Of Motion ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Plate Fixation ◽  
Axial Rotation ◽  
Pedicle Screw Fixation ◽  
Biomechanical Study ◽  
Flexion Extension ◽  
Bilateral Pedicle Screw

Study Design: In vitro cadaveric biomechanical study. Objective: Biomechanically characterize a novel lateral lumbar interbody fusion (LLIF) implant possessing integrated lateral modular plate fixation (MPF). Methods: A human lumbar cadaveric (n = 7, L1-L4) biomechanical study of segmental range-of-motion stiffness was performed. A ±7.5 Nċm moment was applied in flexion/extension, lateral bending, and axial rotation using a 6 degree-of-freedom kinematics system. Specimens were tested first in an intact state and then following iterative instrumentation (L2/3): (1) LLIF cage only, (2) LLIF + 2-screw MPF, (3) LLIF + 4-screw MPF, (4) LLIF + 4-screw MPF + interspinous process fixation, and (5) LLIF + bilateral pedicle screw fixation. Comparative analysis of range-of-motion outcomes was performed between iterations. Results: Key biomechanical findings: (1) Flexion/extension range-of-motion reduction with LLIF + 4-screw MPF was significantly greater than LLIF + 2-screw MPF ( P < .01). (2) LLIF with 2-screw and 4-screw MPF were comparable to LLIF with bilateral pedicle screw fixation in lateral bending and axial rotation range-of-motion reduction ( P = 1.0). (3) LLIF + 4-screw MPF and supplemental interspinous process fixation range-of-motion reduction was comparable to LLIF + bilateral pedicle screw fixation in all directions ( P ≥ .6). Conclusions: LLIF with 4-screw MPF may provide inherent advantages over traditional 2-screw plating modalities. Furthermore, when coupled with interspinous process fixation, LLIF with MPF is a stable circumferential construct that provides biomechanical utility in all principal motions.

IN VITRO STUDY OF BIOMECHANICAL BEHAVIOROF ANTERIORAND TRANSFORAMINAL LUMBARINTERBODY INSTRUMENTATION TECHNIQUES

Neurosurgery ◽  
2006 ◽  
Vol 59 (6) ◽  
pp. 1271-1277 ◽  
Author(s):  
Thomas K. Niemeyer ◽  
Marco Koriller ◽  
Lutz Claes ◽  
Annette Kettler ◽  
Kathrin Werner ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Interbody Fusion ◽  
Screw Fixation ◽  
Axial Rotation ◽  
Pedicle Screw Fixation ◽  
Lumbar Interbody Fusion ◽  
Biomechanical Behavior ◽  
Significant Difference ◽  
Flexion Extension

Abstract OBJECTIVE To study the biomechanical behavior of lumbar interbody instrumentation techniques using titanium cages as either transforaminal lumbar interbody fusion (TLIF) or anterior lumbar interbody fusion (ALIF), with and without posterior pedicle fixation. METHODS Six fresh-frozen lumbar spines (L1–L5) were loaded with pure moments of ±7.5 Nm in unconstrained flexion-extension, lateral bending, and axial rotation. Specimen were tested intact, after implantation of an ALIF or TLIF cage “stand-alone” in L2–L3 or L3–L4, and after additional posterior pedicle screw fixation. RESULTS In all loading directions, the range of motion (ROM) of the segments instrumented with cage and pedicle screw fixation was below the ROM of the intact lumbar specimen for both instrumentation techniques. A significant difference was found between the TLIF cage and the ALIF cage with posterior pedicle screw fixation for the ROM in flexion-extension and axial rotation (P&lt; 0.05). Without pedicle screw fixation, the TLIF cage showed a significantly increased ROM and neutral zone compared with an ALIF cage “stand-alone” in two of the three loading directions (P&lt; 0.05). CONCLUSION With pedicle screw fixation, the ALIF cage provides a higher segmental stability than the TLIF cage in flexion-extension and axial rotation, but the absolute biomechanical differences are minor. The different cage design and approach show only minor differences of segmental stability when combined with posterior pedicle screw fixation.

Pedicle Screw Fixation of the Thoracic Spine: An In Vitro Biomechanical Study on Different Configurations

Spine ◽  
2005 ◽  
Vol 30 (22) ◽  
pp. 2530-2537 ◽  
Author(s):  
Vedat Deviren ◽  
Emre Acaroglu ◽  
Joe Lee ◽  
Masaru Fujita ◽  
Serena Hu ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Thoracic Spine ◽  
Screw Fixation ◽  
Pedicle Screw Fixation ◽  
Biomechanical Study

scholarly journals A Biomechanical Evaluation of a Next-Generation Integrated and Modular ACDF Device Possessing Full-Plate, Half-Plate, and No-Profile Fixation Iterations

2019 ◽  
Vol 9 (8) ◽  
pp. 826-833
Author(s):  
Ripul Panchal ◽  
Anup Gandhi ◽  
Chris Ferry ◽  
Sam Farmer ◽  
Jeremy Hansmann ◽  
...  
Keyword(s):  
Plate Fixation ◽  
Testing Machine ◽  
Axial Rotation ◽  
Biomechanical Study ◽  
The Novel ◽  
Novel Device ◽  
Plate Group ◽  
Flexion Extension ◽  
Group 2

Study Design: In vitro biomechanical study. Objectives: The objective of this in vitro biomechanical range-of-motion (ROM) study was to evaluate spinal segmental stability following fixation with a novel anterior cervical discectomy and fusion (ACDF) device (“novel device”) that possesses integrated and modular no-profile, half-plate, and full-plate fixation capabilities. Methods: Human cadaveric (n = 18, C3-T1) specimens were divided into 3 groups (n = 6/group). Each group would receive one novel device iteration. Specimen terminal ends were potted. Each specimen was first tested in an intact state, followed by anterior discectomy (C5/C6) and iterative instrumentation. Testing order: (1) novel device (group 1, no-profile; group 2, half-plate; group 3, full-plate); (2) novel device (all groups) with lateral mass screws (LMS); (3) traditional ACDF plate + cage; (4) traditional ACDF plate + cage + LMS. A 2 N·m moment was applied in flexion/extension (FE), lateral bending (LB), and axial rotation (AR) via a kinematic testing machine. Segmental ROM was tracked and normalized to intact conditions. Comparative statistical analyses were performed. Results: Key findings: (1) the novel half- and full-plate constructs provided comparable reduction in FE and LB ROM to that of traditional plated ACDF ( P ≥ .05); (2) the novel full-plate construct significantly exceeded all other anterior-only constructs ( P ≤ .05) in AR ROM reduction; and (3) the novel half-plate construct significantly exceeded the no-profile construct in FE ( P < .05). Conclusions: The novel ACDF device may be a versatile alternative to traditional no-profile and independent plating techniques, as it provides comparable ROM reduction in all principle motion directions, across all device iterations.

Biomechanical comparison of single-level posterior versus transforaminal lumbar interbody fusions with bilateral pedicle screw fixation: segmental stability and the effects on adjacent motion segments

2010 ◽  
Vol 12 (6) ◽  
pp. 700-708 ◽  
Author(s):  
Hong Bo Sim ◽  
Judith A. Murovic ◽  
Bo Young Cho ◽  
T. Jesse Lim ◽  
Jon Park
Keyword(s):  
Pedicle Screw ◽  
Screw Fixation ◽  
Pedicle Screw Fixation ◽  
Lateral Bending ◽  
Disc Space ◽  
Fusion Procedure ◽  
Single Level ◽  
Flexion Extension ◽  
Bilateral Pedicle Screw ◽  
Adjacent Segments

Object Both posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) have been frequently undertaken for lumbar arthrodesis. These procedures use different approaches and cage designs, each of which could affect spine stability, even after the addition of posterior pedicle screw fixation. The objectives of this biomechanical study were to compare PLIF and TLIF, each accompanied by bilateral pedicle screw fixation, with regard to the stability of the fused and adjacent segments. Methods Fourteen human L2–S2 cadaveric spine specimens were tested for 6 different modes of motion: flexion, extension, right and left lateral bending, and right and left axial rotation using a load control protocol (LCP). The LCP for each mode of motion utilized moments up to 8.0 Nm at a rate of 0.5 Nm/second with the application of a constant compression follower preload of 400 N. All 14 specimens were tested in the intact state. The specimens were then divided equally into PLIF and TLIF conditions. In the PLIF Group, a bilateral L4–5 partial facetectomy was followed by discectomy and a single-level fusion procedure. In the TLIF Group, a unilateral L4–5 complete facetectomy was performed (and followed by the discectomy and single-level fusion procedure). In the TLIF Group, the implants were initially positioned inside the disc space posteriorly (TLIF-P) and the specimens were tested; the implants were then positioned anteriorly (TLIF-A) and the specimens were retested. All specimens were evaluated at the reconstructed and adjacent segments for range of motion (ROM) and at the adjacent segments for intradiscal pressure (IDP), and laminar strain. Results At the reconstructed segment, both the PLIF and the TLIF specimens had significantly lower ROMs compared with those for the intact state (p < 0.05). For lateral bending, the PLIF resulted in a marked decrease in ROM that was statistically significantly greater than that found after TLIF (p < 0.05). In flexion-extension and rotation, the PLIF Group also had less ROM, however, unlike the difference in lateral bending ROM, these differences in ROM values were not statistically significant. Variations in the position of the implants within the disc space were not associated with any significant differences in ROM values (p = 0.43). Analyses of ROM at the adjacent levels L2–3, L3–4, and L5–S1 showed that ROM was increased to some degree in all directions. When compared with that of intact specimens, the ROMs were increased to a statistically significant degree at all adjacent segments in flexion-extension loads (p < 0.05); however, the differences in values among the various operative procedures were not statistically significant. The IDP and facet contact force for the adjacent L3–4 and L5–S1 levels were also increased, but these values were not statistically significantly increased from those for the intact spine (p > 0.05). Conclusions Regarding stability, PLIF provides a higher immediate stability compared with that of TLIF, especially in lateral bending. Based on our findings, however, PLIF and TLIF, each with posterolateral fusions, have similar biomechanical properties regarding ROM, IDP, and laminar strain at the adjacent segments.

In vitro evaluation of a lateral expandable cage and its comparison with a static device for lumbar interbody fusion: a biomechanical investigation

2014 ◽  
Vol 20 (4) ◽  
pp. 387-395 ◽  
Author(s):  
Sabrina A. Gonzalez-Blohm ◽  
James J. Doulgeris ◽  
Kamran Aghayev ◽  
William E. Lee ◽  
Jake Laun ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Haptic Feedback ◽  
Biomechanical Testing ◽  
Axial Rotation ◽  
Pedicle Screw Fixation ◽  
Interbody Cage ◽  
Disc Space ◽  
Significance Level ◽  
Flexion Extension

Object Through in vitro biomechanical testing, the authors compared the performance of a vertically expandable lateral lumbar interbody cage (EC) under two different torque-controlled expansions (1.5 and 3.0 Nm) and with respect to an equivalent lateral lumbar static cage (SC) with and without pedicle screw fixation. Methods Eleven cadaveric human L2–3 segments were evaluated under the following conditions: 1) intact; 2) discectomy; 3) EC under 1.50 Nm of torque expansion (EC-1.5Nm); 4) EC under 3.00 Nm of torque expansion (EC-3.0Nm); 5) SC; and 6) SC with a bilateral pedicle screw system (SC+BPSS). Load-displacement behavior was evaluated for each condition using a combination of 100 N of axial preload and 7.5 Nm of torque in flexion and extension (FE), lateral bending (LB), and axial rotation (AR). Range of motion (ROM), neutral zone stiffness (NZS), and elastic zone stiffness (EZS) were statistically compared among conditions using post hoc Wilcoxon signed-rank comparisons after Friedman tests, with a significance level of 0.05. Additionally, any cage height difference between interbody devices was evaluated. When radiographic subsidence was observed, the specimen's data were not considered for the analysis. Results The final cage height in the EC-1.5Nm condition (12.1 ± 0.9 mm) was smaller (p < 0.001) than that in the EC-3.0Nm (13.9 ± 1.1 mm) and SC (13.4 ± 0.8 mm) conditions. All instrumentation reduced (p < 0.01) ROM with respect to the injury and increased (p ≤ 0.01) NZS in flexion, extension, and LB as well as EZS in flexion, LB, and AR. When comparing the torque expansions, the EC-3.0Nm condition had smaller (p < 0.01) FE and AR ROM and greater (p ≤ 0.04) flexion NZS, extension EZS, and AR EZS. The SC condition performed equivalently (p ≥ 0.10) to both EC conditions in terms of ROM, NZS, and EZS, except for EZS in AR, in which a marginal (p = 0.05) difference was observed with respect to the EC-3.0Nm condition. The SC+BPSS was the most rigid construct in terms of ROM and stiffness, except for 1) LB ROM, in which it was comparable (p = 0.08) with that of the EC-1.5Nm condition; 2) AR NZS, in which it was comparable (p > 0.66, Friedman test) with that of all other constructs; and 3) AR EZS, in which it was comparable with that of the EC-1.5Nm (p = 0.56) and SC (p = 0.08) conditions. Conclusions A 3.0-Nm torque expansion of a lateral interbody cage provides greater immediate stability in FE and AR than a 1.5-Nm torque expansion. Moreover, the expandable device provides stability comparable with that of an equivalent (in size, shape, and bone-interface material) SC. Specifically, the SC+BPSS construct was the most stable in FE motion. Even though an EC may seem a better option given the minimal tissue disruption during its implantation, there may be a greater chance of endplate collapse by over-distracting the disc space because of the minimal haptic feedback from the expansion.

Biomechanical comparison of stand-alone and bilateral pedicle screws fixation for oblique lumbar inter-body fusion surgery – a finite element analysis

2019 ◽  
Author(s):  
guofang Fang ◽  
yunzhi lin ◽  
wenggang cui ◽  
lili guo ◽  
shihao Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Pedicle Screws ◽  
Element Model ◽  
Axial Rotation ◽  
Pedicle Screw Fixation ◽  
Element Analysis ◽  
Intact Group ◽  
Flexion Extension

Abstract Objectives: The aim of this study was to evaluate the biomechanical stability and safety in patients undergoing oblique lumbar inter-body fusion (OLIF) surgery with stand-alone (SA) and Bilateral pedicle screw fixation (BPSF). Methods: A finite element model of L4-L5 spinal unit was established and validated. Based on the validated model technique, function surgical models corresponding to SA, BPSF were created. Simulations employing the models were performed to investigate the OLIF surgery. A bending moment of 7.5 Nm and a 500 N follower load were applied to the models in flexion, extension, axial rotation and lateral bending. Finite element(FE) models were developed to compare the biomechanics of the intact group, SA, BPSF group. Results: Compared with the Range of motion (ROM) of the intact lumbar model, SA model decreased by 79.5% in flexion, 54.2% in extension, BPSF model decreased by 86.4% in flexion, 70.8% in extension. Compared with the BPSF, the maximum stresses of L4 inferior endplate (IEP) and L5 superior endplate (SEP) increased significantly in SA model, L4 IEP increased to 49.7MPa in extension, L5 SEP increased to 47.7MPa in flexion. Conclusions: OLIF surgery with BPSF could reduce the max stresses of the endplate which may reduce cage sedimentation incidence. However, OLIF surgery with SA could not provide enough rigidity for the fusion segment in osteoporosis patients which may increase the cage sedimentation incidence. Keywords: OLIF; Pedicle screw fixation; spinal fusion; finite element

The biomechanical contribution of varying posterior constructs following anterior thoracolumbar corpectomy and reconstruction

2010 ◽  
Vol 13 (2) ◽  
pp. 234-239 ◽  
Author(s):  
Frank S. Bishop ◽  
Mical M. Samuelson ◽  
Michael A. Finn ◽  
Kent N. Bachus ◽  
Darrel S. Brodke ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Screw Fixation ◽  
Posterior Instrumentation ◽  
Axial Rotation ◽  
Pedicle Screw Fixation ◽  
Bending Stiffness ◽  
Lateral Bending ◽  
Biomechanical Stability ◽  
Flexion Extension ◽  
Anterior Plating

Object Thoracolumbar corpectomy is a procedure commonly required for the treatment of various pathologies involving the vertebral body. Although the biomechanical stability of anterior reconstruction with plating has been studied, the biomechanical contribution of posterior instrumentation to anterior constructs remains unknown. The purpose of this study was to evaluate biomechanical stability after anterior thoracolumbar corpectomy and reconstruction with varying posterior constructs by measuring bending stiffness for the axes of flexion/extension, lateral bending, and axial rotation. Methods Seven fresh human cadaveric thoracolumbar spine specimens were tested intact and after L-1 corpectomy and strut grafting with 4 different fixation techniques: anterior plating with bilateral, ipsilateral, contralateral, or no posterior pedicle screw fixation. Bending stiffness was measured under pure moments of ± 5 Nm in flexion/extension, lateral bending, and axial rotation, while maintaining an axial preload of 100 N with a follower load. Results for each configuration were normalized to the intact condition and were compared using ANOVA. Results Spinal constructs with anterior-posterior spinal reconstruction and bilateral posterior pedicle screws were significantly stiffer in flexion/extension than intact spines or spines with anterior plating alone. Anterior plating without pedicle screw fixation was no different from the intact spine in flexion/extension and lateral bending. All constructs had reduced stiffness in axial rotation compared with intact spines. Conclusions The addition of bilateral posterior instrumentation provided significantly greater stability at the thoracolumbar junction after total corpectomy than anterior plating and should be considered in cases in which anterior column reconstruction alone may be insufficient. In cases precluding bilateral posterior fixation, unilateral posterior instrumentation may provide some additional stability.

Bioabsorbable anterior lumbar plate fixation in conjunction with cage-assisted anterior interbody fusion

2002 ◽  
Vol 97 (4) ◽  
pp. 447-455 ◽  
Author(s):  
Denis J. DiAngelo ◽  
Jeffrey L. Scifert ◽  
Scott Kitchel ◽  
G. Bryan Cornwall ◽  
Bobby J. McVay
Keyword(s):  
Interbody Fusion ◽  
Plate Fixation ◽  
Axial Rotation ◽  
Biomechanical Study ◽  
Local Motion ◽  
Content Type ◽  
Flexion Extension ◽  
Spine Model ◽  
Fine Print

Object. An in vitro biomechanical study was conducted to determine the effects of anterior stabilization on cage-assisted lumbar interbody fusion biomechanics in a multilevel human cadaveric lumbar spine model. Methods. Three spine conditions were compared: harvested, bilateral multilevel cages (CAGES), and CAGES with bioabsorbable anterior plates (CBAP), tested under flexion—extension, lateral bending, and axial rotation. Measurements included vertebral motion, applied load, and bending/rotational moments. Application of anterior fixation decreased local motion and increased stiffness of the instrumented levels. Clinically, this spinal stability may serve to promote fusion. Conclusions. Coupled with the bioabsorbability of the plating material, the bioabsorbable anterior lumbar plating system is considered biomechanically advantageous.

In Vitro Biomechanical Analysis of a New Lumbar Low-Profile Locking Screw-Plate Construct Versus a Standard Top-Loading Cantilevered Pedicle Screw-Rod Construct

Neurosurgery ◽  
2010 ◽  
Vol 66 (2) ◽  
pp. E404-E406 ◽  
Author(s):  
Neil R. Crawford ◽  
Şeref Doğan ◽  
K. Zafer Yüksel ◽  
Octavio Villasana-Ramos ◽  
Julio C. Soto-Barraza ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Pedicle Screw ◽  
Axial Rotation ◽  
Biomechanical Analysis ◽  
Posterior Fixation ◽  
Low Profile ◽  
Flexion Extension ◽  
Rod System ◽  
Plate System

Abstract OBJECTIVE A standard top-loading lumbar pedicle screw-rod system is compared with a pedicle screw-plate system with smaller-diameter screws, more medial entry, and lower profile to assess the relative stability, strength, and resistance to fatigue of the 2 systems. METHODS Seven human cadaveric specimens were studied with each surgical construct. Nondestructive, nonconstraining pure moments were applied to specimens to induce flexion, extension, lateral bending, and axial rotation while recording L5–S1 motion optoelectronically. After initial tests, specimens were fatigued for 10 000 cycles and retested to assess early postoperative loosening. Specimens were then loaded to failure in hyperextension. RESULTS The standard screw-rod construct reduced range of motion to a mean of 20% of normal, whereas the screw-plate construct reduced range of motion to 13% of normal. Differences between systems were not significant in any loading mode (P &gt; 0.06). The 14% loosening of the screw-rod system with fatigue was not significantly different from the 10% loosening observed with the screw-plate system (P &gt; 0.15). Mean failure loads of 30 Nm for screw-rod and 37 Nm for screw-plate were also not significantly different (P = 0.38). CONCLUSION Posterior fixation at L5–S1 using the low-profile screw-plate system offers stability, resistance to fatigue, and resistance to failure equivalent to fixation using a standard cantilevered pedicle screw-rod system.

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