Comparative analysis of posterior fusion constructs as treatments for middle and posterior column injuries: An in vitro biomechanical investigation

Doulgeris, James; Aghayev, Kamran; Gonzalez-Blohm, Sabrina A.; Valle, Michael Del; Waddell, Jason K.; Lee, William; Vrionis, Frank D.

doi:10.1016/j.clinbiomech.2013.05.001

Cited by 20 publications

(24 citation statements)

References 28 publications

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“…Specimens were coated with petroleum jelly during testing to minimize dehydration, 22 and they were wrapped with 4 × 4-in gauze sponges moistened with 0.9% NaCl solution when not being tested. 5 …”

Section: Specimen Preparationmentioning

confidence: 99%

“…5 Energy loss indicates the probability of the segment maintaining the (corrected) balance in a specific plane, which in turn translates to the chances of segmental micromotions that could inhibit bony fusion. Clinically, EL can be interpreted as the likelihood of preserving sagittal (flexion-extension), coronal (lateral bending), and axial (axial rotation) balance.…”

Section: Preservation Of Balancementioning

confidence: 99%

“…25 The EL (Nm*°) was estimated from the hysteresis loop using trap-ezoidal integration. 5 These parameters were compared among the following conditions: 1) intact (Fig. 2A); 2) left hemilaminotomy and partial (approximately 10%-20%) discectomy (Fig.…”

Section: Biomechanical Testingmentioning

confidence: 99%

“…The testing apparatus consisted of a servo hydraulic machine (MTS 858 MiniBionix modified by Instron) that allows axial rotation translation, and two custom-made frames (superior and inferior) that allow bending moments (in one direction) through pulley systems, as described in previous publications. 5 Specimens were subjected to 100 N of axial preload and ± 7.5 Nm of controlled torque for flexion-extension, right/left bending, and right/left axial rotation. 4 Six cycles of axial rotation torque (± 0.1 Nm) were dynamically applied at a rate of 0.125 Hz, while 3 cycles of quasistatic bending moments (flexion, extension, and right/left bending) were performed in increments of 1.5 Nm.…”

Section: Biomechanical Testingmentioning

confidence: 99%

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Biomechanical analysis of an interspinous fusion device as a stand-alone and as supplemental fixation to posterior expandable interbody cages in the lumbar spine

Gonzalez-Blohm

Doulgeris

Aghayev

et al. 2014

SPI

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Object In this paper the authors evaluate through in vitro biomechanical testing the performance of an interspinous fusion device as a stand-alone device, after lumbar decompression surgery, and as supplemental fixation to expandable cages in a posterior lumbar interbody fusion (PLIF) construct. Methods Nine L3–4 human cadaveric spines were biomechanically tested under the following conditions: 1) intact/control; 2) L3–4 left hemilaminotomy with partial discectomy (injury); 3) interspinous spacer (ISS); 4) bilateral pedicle screw system (BPSS); 5) bilateral hemilaminectomy, discectomy, and expandable posterior interbody cages with ISS (PLIF-ISS); and 6) PLIF-BPSS. Each test consisted of 100 N of axial preload with ± 7.5 Nm of torque in flexion-extension, right/left lateral bending, and right/left axial rotation. Significant changes in range of motion (ROM), neutral zone stiffness (NZS), elastic zone stiffness (EZS), and energy loss (EL) were explored among conditions using nonparametric Friedman test and Wilcoxon signed-rank comparisons (p ≤ 0.05). Results The injury increased ROM in flexion (p = 0.01), left bending (p = 0.03), and right/left rotation (p < 0.01) and also decreased NZS in flexion (p = 0.01) and extension (p < 0.01). Both the ISS and BPSS reduced flexion-extension ROM and increased flexion-extension stiffness (NZS and EZS) with respect to the injury and intact conditions (p < 0.05), but the ISS condition provided greater resistance than BPSS in extension for ROM, NZS, and EZS (p < 0.01). The BPSS increased the rigidity (ROM, NZS, and EZS) of the intact model in lateral bending and axial rotation (p ≤ 0.01), except in EZS for left rotation (p = 0.23, Friedman test). The incorporation of posterior cages marginally increased (p = 0.05) the EZS of the BPSS construct in flexion but these interbody devices provided significant stability to the ISS construct in lateral bending and axial rotation for ROM (p = 0.02), in lateral bending for NZS (p = 0.02), and in flexion/axial rotation for EZS (p ≤ 0.03); however, both PLIF constructs demonstrated equivalent ROM and stiffness (p ≥ 0.16), except in lateral bending where the PLIF-BPSS was more stable (p = 0.02). In terms of EL, the injury increased EL in flexion-extension (p = 0.02), the ISS increased EL for lateral bending and axial rotation (p ≤ 0.03), and the BPSS decreased EL in lateral bending (p = 0.02), with respect to the intact condition. The PLIF-ISS decreased lateral bending EL with respect to the ISS condition (p = 0.02), but not enough to be smaller or, at least, equivalent, to that of the PLIF-BPSS construct (p = 0.02). Conclusions The ISS may be a suitable device to provide immediate flexion-extension balance after a unilateral laminotomy, but the BPSS provides greater immediate stability in lateral bending and axial rotation motions. Both PLIF constructs performed equivalently in flexion-extension and axial rotation, but the PLIF-BPSS construct is more resistant to lateral bending motions. Further biomechanical and clinical evidence is required to strongly support the recommendation of a stand-alone interspinous fusion device or as supplemental fixation to expandable posterior interbody cages.

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Section: Specimen Preparationmentioning

confidence: 99%

Section: Preservation Of Balancementioning

confidence: 99%

Section: Biomechanical Testingmentioning

confidence: 99%

Section: Biomechanical Testingmentioning

confidence: 99%

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Biomechanical analysis of an interspinous fusion device as a stand-alone and as supplemental fixation to posterior expandable interbody cages in the lumbar spine

Gonzalez-Blohm

Doulgeris

Aghayev

et al. 2014

SPI

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“…Spinal segments were affixed in a mixture of Bondo autobody filler (Bondo Corp.) and fiberglass resin (3M) 21 via 2-inch self-tapping screws in the free endplates and/ or facets of the L2-3 segments. Horizontal alignment of the intervertebral joint was verified during curing of the Bondo-fiberglass mixture by using a series of leveling tools and customized potting frames, as described previously, 7 to ensure proper force transmission during biomechanical testing. Dissection and testing were performed at room temperature (21° ± 2°C) in a period no longer than 48 hours.…”

Section: Specimen Preparationmentioning

confidence: 99%

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

Gonzalez-Blohm

Doulgeris

Aghayev

et al. 2014

SPI

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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.

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Material Selection Impact on Intraoperative Spine Manipulation and Post-op Correction Maintenance

Zakaria¹,

Marca²

2019

Handbook of Spine Technology

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Comparative analysis of posterior fusion constructs as treatments for middle and posterior column injuries: An in vitro biomechanical investigation

Cited by 20 publications

References 28 publications

Biomechanical analysis of an interspinous fusion device as a stand-alone and as supplemental fixation to posterior expandable interbody cages in the lumbar spine

Biomechanical analysis of an interspinous fusion device as a stand-alone and as supplemental fixation to posterior expandable interbody cages in the lumbar spine

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

Material Selection Impact on Intraoperative Spine Manipulation and Post-op Correction Maintenance

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