Ex vivo study of the intradiskal pressure in the C6-7 intervertebral disk after experimental destabilization and distraction-fusion of the C5-C6 vertebrae in canine cadaveric specimens

2021 ◽  
pp. 1-10
Author(s):  
Sebastian C. Knell ◽  
Brian Park ◽  
Benjamin Voumard ◽  
Antonio Pozzi
Keyword(s):  
Nucleus Pulposus ◽  
Annulus Fibrosus ◽  
Degrees Of Freedom ◽  
Ex Vivo ◽  
Intervertebral Disk ◽  
Custom Made ◽  
Measurement Protocol ◽  
Flexion Extension ◽  
Bending Loads ◽  
6 Degrees Of Freedom

Abstract OBJECTIVE To evaluate intradiskal pressure (IDP) in the C6-7 intervertebral disk (IVD) after destabilization and distraction-fusion of the C5-C6 vertebrae. SAMPLE 7 cadaveric C4-T1 vertebral specimens with no evidence of IVD disease from large-breed dogs. PROCEDURES Specimens were mounted in a custom-made 6 degrees of freedom spinal loading simulator so the C5-C6 and C6-C7 segments remained mobile. One specimen remained untreated and was used to assess the repeatability of the IDP measurement protocol. Six specimens underwent 3 sequential configurations (untreated, partial diskectomy of the C5-6 IVD, and distraction-fusion of the C5-C6 vertebrae). Each construct was biomechanically tested under neutral, flexion, extension, and right-lateral bending loads. The IDP was measured with a pressure transducer inserted into the C6-7 IVD and compared between the nucleus pulposus and annulus fibrosus and across all 3 constructs and 4 loads. RESULTS Compared with untreated constructs, partial diskectomy and distraction-fusion of C5-C6 decreased the mean ± SD IDP in the C6-7 IVD by 1.3 ± 1.3% and 0.8 ± 1.3%, respectively. During motion, the IDP remained fairly constant in the annulus fibrosus and increased by 3.8 ± 3.0% in the nucleus pulposus. The increase in IDP within the nucleus pulposus was numerically greatest during flexion but did not differ significantly among loading conditions. CONCLUSIONS AND CLINICAL RELEVANCE Distraction-fusion of C5-C6 did not significantly alter the IDP of healthy C6-7 IVDs. Effects of vertebral distraction-fusion on the IDP of adjacent IVDs with degenerative changes, such as those in dogs with caudal cervical spondylomyelopathy, warrant investigation.

Low Wear Debris Compliant Mechanism Cervical Disc Prosthesis

2020 ◽  
Author(s):  
Samuel Brehm
Keyword(s):  
Wear Debris ◽  
Degrees Of Freedom ◽  
Compliant Mechanism ◽  
Cervical Disc ◽  
Disc Prosthesis ◽  
Flexion Extension ◽  
Cervical Disc Prosthesis ◽  
Length Width ◽  
6 Degrees Of Freedom ◽  
Single Part

Abstract The device outlined in this paper is 3D printable cervical disc prosthesis that uses a compliant mechanism to behave biomechanically like a natural cervical intervertebral disc. The device is DMLS printed out of biocompatible titanium as a single part, and can be manufactured to the custom length, width, height, and lordotic angle desired for the patient. The device has 6 degrees of freedom for flexion, extension, and lateral bending. The device has 0.83 mm of max compression with a compressive stiffness of 473.1 N/mm. The device consists of compliant mechanism with two plates fused on the top and bottom. The mechanism is essentially two perpendicular beams fused at their midpoints. The beams act as rotational as well as compressive springs. This allows the rotational and compressive range of motion. This design is intended to minimize the production of wear debris, which is a problem with prosthetics. It also provides the ability for a disc prosthesis to be easily custom manufactured for the patient.

Functional Validation of a Complex Loading Whole Spinal Segment Bioreactor Design

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Amanda M. Beatty ◽  
Anton E. Bowden ◽  
Laura C. Bridgewater
Keyword(s):  
Ex Vivo ◽  
Complex Loading ◽  
Intervertebral Disk ◽  
Tissue Response ◽  
Spinal Segment ◽  
Applied Torque ◽  
Flexion Extension ◽  
Loading System ◽  
Vertebral Bodies

Intervertebral disk (IVD) degeneration is a prevalent health problem that is highly linked to back pain. To understand the disease and tissue response to therapies, ex vivo whole IVD organ culture systems have recently been introduced. The goal of this work was to develop and validate the design of a whole spinal segment culturing system that loads the disk in complex loading similar to the in vivo condition, while preserving the adjacent endplates and vertebral bodies. The complex loading applied to the spinal segment (flexion–extension (FE), bilateral bending, and compression) was achieved with three pneumatic cylinders rigidly attached to a triangular loading platform. A culture container housed the spinal segment and was attached to the loading mechanism, which allowed for loading of the spinal segment. The dynamic bioreactor was able to achieve physiologic loading conditions with 100 N of applied compression and approximately 2–4 N · m of applied torque. The function of the bioreactor was validated through testing of bovine caudal IVDs with intact endplates and vertebral bodies that were isolated within 2 hrs of death and cultured for 14 days. The resulting IVD cell viability following 14 days of loading was much higher than unloaded control IVDs. The loading system accurately mimicked FE, bilateral bending, and compression motions seen during daily activities. The results indicate that this complex dynamic bioreactor may be appropriate for extended preclinical testing of vertebral-mounted spinal devices and therapies.

scholarly journals Advances and Prospects in Biomaterials for Intervertebral Disk Regeneration

2021 ◽  
Vol 9 ◽  
Author(s):  
Chunxu Li ◽  
Qiushi Bai ◽  
Yuxiao Lai ◽  
Jingjing Tian ◽  
Jiahao Li ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Nucleus Pulposus ◽  
Cell Transplantation ◽  
Annulus Fibrosus ◽  
Functional Polymers ◽  
Intervertebral Disk ◽  
Fusion Surgery ◽  
Intervertebral Disk Degeneration ◽  
Disk Degeneration ◽  
Intervertebral Disks

Low-back and neck-shoulder pains caused by intervertebral disk degeneration are highly prevalent among middle-aged and elderly people globally. The main therapy method for intervertebral disk degeneration is surgical intervention, including interbody fusion, disk replacement, and diskectomy. However, the stress changes caused by traditional fusion surgery are prone to degeneration of adjacent segments, while non-fusion surgery has problems, such as ossification of artificial intervertebral disks. To overcome these drawbacks, biomaterials that could endogenously regenerate the intervertebral disk and restore the biomechanical function of the intervertebral disk is imperative. Intervertebral disk is a fibrocartilaginous tissue, primarily comprising nucleus pulposus and annulus fibrosus. Nucleus pulposus (NP) contains high water and proteoglycan, and its main function is absorbing compressive forces and dispersing loads from physical activities to other body parts. Annulus fibrosus (AF) is a multilamellar structure that encloses the NP, comprises water and collagen, and supports compressive and shear stress during complex motion. Therefore, different biomaterials and tissue engineering strategies are required for the functional recovery of NP and AF based on their structures and function. Recently, great progress has been achieved on biomaterials for NP and AF made of functional polymers, such as chitosan, collagen, polylactic acid, and polycaprolactone. However, scaffolds regenerating intervertebral disk remain unexplored. Hence, several tissue engineering strategies based on cell transplantation and growth factors have been extensively researched. In this review, we summarized the functional polymers and tissue engineering strategies of NP and AF to endogenously regenerate degenerative intervertebral disk. The perspective and challenges of tissue engineering strategies using functional polymers, cell transplantation, and growth factor for generating degenerative intervertebral disks were also discussed.

scholarly journals Biomechanical evaluation of annulus fibrosus repair with scaffold and soft anchors in an ex vivo porcine model

SICOT-J ◽  
2018 ◽  
Vol 4 ◽  
pp. 38 ◽  
Author(s):  
Kresten Rickers ◽  
Michael Bendtsen ◽  
Dang Quang Svend Le ◽  
Albert Jvan der Veen ◽  
Cody Eric Bünger
Keyword(s):  
Annulus Fibrosus ◽  
Ex Vivo ◽  
Biomechanical Testing ◽  
Biomechanical Properties ◽  
Neutral Zone ◽  
Lateral Bending ◽  
Biomechanical Behavior ◽  
Flexion Extension ◽  
Circular Defect ◽  
Push Out

Introduction: Altered biomechanical properties, due to intervertebral disc (IVD) degeneration and missing nucleus fibrosus, could be thought as one of the reasons for the back pain many herniation patients experience after surgery. It has been suggested to repair annulus fibrosus (AF) to restore stability and allow nucleus pulposus (NP) replacement and furthermore prevent reherniation. The aim of this study was to evaluate a new method for closing a defect in AF for use in herniation surgery. Methods: Our repair method combines a polycaprolactone (PCL) scaffold plugging herniation and soft anchors to secure the plug. Ex vivo biomechanical testing was carried out in nine porcine lumbar motion segments. Flexion–extension, lateral bending and rotation were repeated three times: first in healthy specimens, second with a full thickness circular defect applied, and third time with the specimens repaired. Finally push out tests were performed to check whether the plug would remain in. Results: Tests showed that applying a defect to the AF increases the range of motion (ROM), neutral zone (NZ) and neutral zone stiffness (NZS). In flexion/extension it was found significant for ROM, NZ, and NZS. For lateral bending and rotation a significant increase in ROM occurred. After AF repair ROM, NZ and NZS were normalized. All plugs remained in the AF during push out test up until 4000 N, but NP was squeezed out through the pores of the scaffold. Discussion: A defect in the AF changes the biomechanical properties in the motion segment, changes that point to instability. Repairing the defect with a PCL plug and soft anchors brought the biomechanical behavior back to native state. This concept is promising and might be a viable way to repair the IVD after surgery.

Initial investigation of individual and combined annulus fibrosus and nucleus pulposus repair ex vivo

2017 ◽  
Vol 59 ◽  
pp. 192-199 ◽  
Author(s):  
Stephen R. Sloan ◽  
Devis Galesso ◽  
Cynthia Secchieri ◽  
Connor Berlin ◽  
Roger Hartl ◽  
...  
Keyword(s):  
Nucleus Pulposus ◽  
Annulus Fibrosus ◽  
Ex Vivo ◽  
Initial Investigation

Biomechanical analysis of anterior versus posterior instrumentation following a thoracolumbar corpectomy

2014 ◽  
Vol 21 (4) ◽  
pp. 577-581 ◽  
Author(s):  
Stephanus V. Viljoen ◽  
Nicole A. DeVries Watson ◽  
Nicole M. Grosland ◽  
James Torner ◽  
Brian Dalm ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Degrees Of Freedom ◽  
Screw Fixation ◽  
Axial Rotation ◽  
Pedicle Screw Fixation ◽  
Lateral Bending ◽  
Short Segment ◽  
Intact State ◽  
Flexion Extension ◽  
6 Degrees Of Freedom

Object The objective of this study was to evaluate the biomechanical properties of lateral instrumentation compared with short- and long-segment pedicle screw constructs following an L-1 corpectomy and reconstruction with an expandable cage. Methods Eight human cadaveric T10–L4 spines underwent an L-1 corpectomy followed by placement of an expandable cage. The spines then underwent placement of lateral instrumentation consisting of 4 monoaxial screws and 2 rods with 2 cross-connectors, short-segment pedicle screw fixation involving 1 level above and below the corpectomy, and long-segment pedicle screw fixation (2 levels above and below). The order of instrumentation was randomized in the 8 specimens. Testing was conducted for each fixation technique. The spines were tested with a pure moment of 6 Nm in all 6 degrees of freedom (flexion, extension, right and left lateral bending, and right and left axial rotation). Results In flexion, extension, and left/right lateral bending, posterior long-segment instrumentation had significantly less motion compared with the intact state. Additionally, posterior long-segment instrumentation was significantly more rigid than short-segment and lateral instrumentation in flexion, extension, and left/right lateral bending. In axial rotation, the posterior long-segment construct as well as lateral instrumentation were not significantly more rigid than the intact state. The posterior long-segment construct was the most rigid in all 6 degrees of freedom. Conclusions In the setting of highly unstable fractures requiring anterior reconstruction, and involving all 3 columns, long-segment posterior pedicle screw constructs are the most rigid.

scholarly journals Raloxifene retards the progression of adjacent segmental intervertebral disc degeneration by inhibiting apoptosis of nucleus pulposus in ovariectomized rats

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Qi Sun ◽  
Xin-Yu Nan ◽  
Fa-Ming Tian ◽  
Fang Liu ◽  
Shao-Hua Ping ◽  
...  
Keyword(s):  
Nucleus Pulposus ◽  
Lumbar Fusion ◽  
B Cell Lymphoma ◽  
Intervertebral Disk ◽  
Ovariectomized Rats ◽  
Tunel Staining ◽  
Mineral Density ◽  
Vertebral Osteoporosis ◽  
Intervertebral Disk Degeneration ◽  
Disk Degeneration

Abstract Background Adjacent segmental intervertebral disk degeneration (ASDD) is a major complication secondary to lumbar fusion. Although ASSD pathogenesis remains unclear, the primary cause of intervertebral disk degeneration (IVDD) development is apoptosis of nucleus pulposus (NP). Raloxifene (RAL) could delay ASDD by inhibiting NP apoptosis. Methods An ASDD rat model was established by ovariectomy (OVX) and posterolateral spinal fusion (PLF) on levels 4–5 of the lumbar vertebrae. Rats in the treatment groups were administered 1 mg/kg/d RAL by gavage for 12 weeks, following which, all animals were euthanized. Lumbar fusion, apoptosis, ASDD, and vertebrae micro-architecture were evaluated. Results RAL maintained intervertebral disk height (DHI), delayed vertebral osteoporosis, reduced histological score, and inhibited apoptosis. The OVX+PLF+RAL group revealed upregulated expression of aggrecan and B-cell lymphoma-2 (bcl2), as well as significantly downregulated expression of a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS-4), metalloproteinase-13 (MMP-13), caspase-3, BCL2-associated X (bax), and transferase dUTP nick end labeling (TUNEL) staining. Micro-computed tomography (Micro-CT) analysis revealed higher bone volume fraction (BV/TV), bone mineral density (BMD), and trabecular number (Tb.N), and lower trabecular separation (Tb.Sp) in OVX+PLF+RAL group than in the OVX+PLF group. Conclusions RAL can postpone ASDD development in OVX rats through inhibiting extracellular matrix metabolic imbalance, NP cell apoptosis, and vertebral osteoporosis. These findings showed RAL as a potential therapeutic target for ASDD.

scholarly journals Annular Defects Impair the Mechanical Stability of the Intervertebral Disc

2021 ◽  
pp. 219256822110060
Author(s):  
Jun-Xin Chen ◽  
Yun-He Li ◽  
Jian Wen ◽  
Zhen Li ◽  
Bin-Sheng Yu ◽  
...  
Keyword(s):  
Intervertebral Disc ◽  
Degrees Of Freedom ◽  
Mechanical Stability ◽  
Biomechanical Testing ◽  
Bending Stiffness ◽  
Biomechanical Study ◽  
Torsional Stiffness ◽  
P Value ◽  
Lateral Bending ◽  
Flexion Extension

Study Design: A biomechanical study. Objectives: The purpose of this study was to investigate the effects of cruciform and square incisions of annulus fibrosus (AF) on the mechanical stability of bovine intervertebral disc (IVD) in multiple degrees of freedom. Methods: Eight bovine caudal IVD motion segments (bone-disc-bone) were obtained from the local abattoir. Cruciform and square incisions were made at the right side of the specimen’s annulus using a surgical scalpel. Biomechanical testing of three-dimensional 6 degrees of freedom was then performed on the bovine caudal motion segments using the mechanical testing and simulation (MTS) machine. Force, displacement, torque and angle were recorded synchronously by the MTS system. P value <.05 was considered statistically significant. Results: Cruciform and square incisions of the AF reduced both axial compressive and torsional stiffness of the IVD and were significantly lower than those of the intact specimens ( P < .01). Left-side axial torsional stiffness of the cruciform incision was significantly higher than a square incision ( P < .01). Neither incision methods impacted flexional-extensional stiffness or lateral-bending stiffness. Conclusions: The cruciform and square incisions of the AF obviously reduced axial compression and axial rotation, but they did not change the flexion-extension and lateral-bending stiffness of the bovine caudal IVD. This mechanical study will be meaningful for the development of new approaches to AF repair and the rehabilitation of the patients after receiving discectomy.

4D in in vivo 2-photon laser scanning fluorescence microscopy with sample motion in 6 degrees of freedom

2011 ◽  
Vol 200 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Sabine Scheibe ◽  
Mario M. Dorostkar ◽  
Christian Seebacher ◽  
Rainer Uhl ◽  
Frank Lison ◽  
...  
Keyword(s):  
Fluorescence Microscopy ◽  
Laser Scanning ◽  
Degrees Of Freedom ◽  
Sample Motion ◽  
6 Degrees Of Freedom

scholarly journals Extra-gastric expression of the proton pump H+/K+-ATPase in the gills and kidney of the teleost Oreochromis niloticus

2020 ◽  
Vol 223 (16) ◽  
pp. jeb214890
Author(s):  
Ebtesam Ali Barnawi ◽  
Justine E. Doherty ◽  
Patrícia Gomes Ferreira ◽  
Jonathan M. Wilson
Keyword(s):  
Oreochromis Niloticus ◽  
Cellular Localization ◽  
Ex Vivo ◽  
Uptake Inhibition ◽  
Custom Made ◽  
Potassium Regulation ◽  
Immunohistochemical Techniques ◽  
Collecting Tubules ◽  
First Time

ABSTRACTPotassium regulation is essential for the proper functioning of excitable tissues in vertebrates. The H+/K+-ATPase (HKA), which is composed of the HKα1 (gene: atp4a) and HKβ (gene: atp4b) subunits, has an established role in potassium and acid–base regulation in mammals and is well known for its role in gastric acidification. However, the role of HKA in extra-gastric organs such as the gill and kidney is less clear, especially in fishes. In the present study in Nile tilapia, Oreochromis niloticus, uptake of the K+ surrogate flux marker rubidium (Rb+) was demonstrated in vivo; however, this uptake was not inhibited with omeprazole, a potent inhibitor of the gastric HKA. This contrasts with gill and kidney ex vivo preparations, where tissue Rb+ uptake was significantly inhibited by omeprazole and SCH28080, another gastric HKA inhibitor. The cellular localization of this pump in both the gill and kidney was demonstrated using immunohistochemical techniques with custom-made antibodies specific for Atp4a and Atp4b. Antibodies against the two subunits showed the same apical ionocyte distribution pattern in the gill and collecting tubules/ducts in the kidney. Atp4a antibody specificity was confirmed by western blotting. RT-PCT was used to confirm the expression of both subunits in the gill and kidney. Taken together, these results indicate for the first time K+ (Rb+) uptake in O. niloticus and that HKA is implicated, as shown through the ex vivo uptake inhibition by omeprazole and SCH28080, verifying a role for HKA in K+ absorption in the gill's ionocytes and collecting tubule/duct segments of the kidney.

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