Intervertebral Ligaments Research Articles

Examination of a lumbar spine biomechanical model for assessing axial compression, shear, and bending moment using selected Olympic lifts

Background/AimsLoading during concurrent bending and compression associated with deadlift, hang clean and hang snatch lifts carries the potential for injury to the intervertebral discs, muscles and ligaments. This study examined the capacity of a newly developed spinal model to compute shear and compressive forces, and bending moments in lumbar spine for each lift. MethodsFive male subjects participated in the study. The spine was modeled as a chain of rigid bodies (vertebrae) connected via the intervertebral discs. Each vertebral reference frame was centered in the center of mass of the vertebral body, and its principal directions were axial, anterior-posterior, and medial-lateral. ResultsThe results demonstrated the capacity of this spinal model to assess forces and bending moments at and about the lumbar vertebrae by showing the variations among these variables with different lifting techniques. ConclusionThese results show the model's potential as a diagnostic tool.

A forward dynamics simulation of human lumbar spine flexion predicting the load sharing of intervertebral discs, ligaments, and muscles.

Determining the internal dynamics of the human spine's biological structure is one essential step that allows enhanced understanding of spinal degeneration processes. The unavailability of internal load figures in other methods highlights the importance of the forward dynamics approach as the most powerful approach to examine the internal degeneration of spinal structures. Consequently, a forward dynamics full-body model of the human body with a detailed lumbar spine is introduced. The aim was to determine the internal dynamics and the contribution of different spinal structures to loading. The multi-body model consists of the lower extremities, two feet, shanks and thighs, the pelvis, five lumbar vertebrae, and a lumped upper body including the head and both arms. All segments are modelled as rigid bodies. 202 muscles (legs, back, abdomen) are included as Hill-type elements. 58 nonlinear force elements are included to represent all spinal ligaments. The lumbar intervertebral discs were modelled nonlinearly. As results, internal kinematics, muscle forces, and internal loads for each biological structure are presented. A comparison between the nonlinear (new, enhanced modelling approach) and linear (standard modelling approach, bushing) modelling approaches of the intervertebral disc is presented. The model is available to all researchers as ready-to-use C/C++ code within our in-house multi-body simulation code demoa with all relevant binaries included.

Lower back pain

Lower back pain (LBP) is one of the most common and costly medical problems today [1, 2]. Pain is usually transitory and can arise from the intervertebral discs, bones, ligaments and muscles of the spine. Risk factors for LBP include genetic, environmental, psychosocial and biomechanical influences [3]. However, although 85% of LBP cases have no clear etiology, 97% may be due to musculoskeletal issues [4]. Lumbar curvature (lordosis) is one factor that generates shearing between adjacent vertebrae and at intervertebral joints. People with high degrees of lumbar lordosis, including pregnant women, can experience excessive shearing (Fshear) and compression (Fcompression) forces between lumbar vertebrae, most often between the last lumbar and the sacrum [3, 5]. In addition to other factors, including age-related spinal degeneration, high levels of Fshear and Fcompression can lead to painful muscle strain, joint capsule pain, disc herniation, inflammation (spondylitis), bone degeneration (spondylolysis) and vertebral displacement (spondylolisthesis) [3–5]. Evolutionary perspectives

Vertebral deformities in hatchery-reared and wild-caught juvenile Japanese flounder, Paralichthys olivaceus

The present study compared vertebral deformities of hatchery-reared and wild-caught juvenile Japanese flounder, Paralichthys olivaceus. A total of 362 hatchery-reared flounder (total length 122.5–155.8 mm) were collected from three commercial hatcheries located in Yantai, East China, and 89 wild fish (total length 124.7–161.3 mm) were caught off Yangma Island near Yantai City (37°27′N, 121°36′E). All the fish were dissected, photographed, and images of the axial skeleton were examined for vertebral deformities. Compared with wild-caught flounder in which no deformed vertebrae were detected, 48 (13.3%) hatcheryreared fish had deformed vertebrae. The deformities were classified as compression, compression-ankylosis, and dislocation-ankylosis. The vertebral deformities were mainly localized between post-cranial vertebra 1 and 3, with vertebrae number 1 as the most commonly deformed. The causative factors leading to vertebral deformities in reared Japanese flounder may be related to unfavorable temperature conditions, inflammation, damage, or rupture to the intervertebral ligaments under rearing conditions. Furthermore, no significant difference in the total number of vertebral bodies was observed between wild-caught (38.8±0.4) and hatchery-reared flounder (38.1±0.9) (P>0.05). However, the number of vertebral bodies of hatchery-reared and wild-caught flounder ranged from 35 to 39 and from 38 to 39, respectively.

Development and Validation of a 10-Year-Old Child Ligamentous Cervical Spine Finite Element Model

Although a number of finite element (FE) adult cervical spine models have been developed to understand the injury mechanisms of the neck in automotive related crash scenarios, there have been fewer efforts to develop a child neck model. In this study, a 10-year-old ligamentous cervical spine FE model was developed for application in the improvement of pediatric safety related to motor vehicle crashes. The model geometry was obtained from medical scans and meshed using a multi-block approach. Appropriate properties based on review of literature in conjunction with scaling were assigned to different parts of the model. Child tensile force–deformation data in three segments, Occipital-C2 (C0–C2), C4–C5 and C6–C7, were used to validate the cervical spine model and predict failure forces and displacements. Design of computer experiments was performed to determine failure properties for intervertebral discs and ligaments needed to set up the FE model. The model-predicted ultimate displacements and forces were within the experimental range. The cervical spine FE model was validated in flexion and extension against the child experimental data in three segments, C0–C2, C4–C5 and C6–C7. Other model predictions were found to be consistent with the experimental responses scaled from adult data. The whole cervical spine model was also validated in tension, flexion and extension against the child experimental data. This study provided methods for developing a child ligamentous cervical spine FE model and to predict soft tissue failures in tension.

Posterior ligamentous complex healing following disruption in thoracolumbar fractures

Classification schemes for thoracolumbar fractures attempt to categorize them as either stable or unstable. Stable fractures heal with conservative treatment strategies such as bracing, while unstable fractures require operative internal fixation. Until recently, most classification schemes recognized the importance of the pattern and location of bony disruption in segregating stable and unstable fractures. Recently, the integrity of the posterior ligamentous complex was found to influence the degree of the stability of thoracolumbar fractures. Disruption of the intervertebral disc and ligaments increases spinal instability. Unlike bone, it is thought that these ligaments do not have the capacity to heal. However, this notion is not founded by substantial evidence. It is, hence, important to determine the extent of ligamentous healing in the spine as this will influence directing therapy towards not only bony fusion, but also ligamentous union.

Computed tomography of the cervical spine: comparison of image quality between a standard-dose and a low-dose protocol using filtered back-projection and iterative reconstruction

To compare image quality of a standard-dose (SD) and a low-dose (LD) cervical spine CT protocol using filtered back-projection (FBP) and iterative reconstruction (IR). Forty patients investigated by cervical spine CT were prospectively randomised into two groups: SD (120 kVp, 275 mAs) and LD (120 kVp, 150 mAs), both applying automatic tube current modulation. Data were reconstructed using both FBP and sinogram-affirmed IR. Image noise, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were measured. Two radiologists independently and blindly assessed the following anatomical structures at C3-C4 and C6-C7 levels, using a four-point scale: intervertebral disc, content of neural foramina and dural sac, ligaments, soft tissues and vertebrae. They subsequently rated overall image quality using a ten-point scale. For both protocols and at each disc level, IR significantly decreased image noise and increased SNR and CNR, compared with FBP. SNR and CNR were statistically equivalent in LD-IR and SD-FBP protocols. Regardless of the dose and disc level, the qualitative scores with IR compared with FBP, and with LD-IR compared with SD-FBP, were significantly higher or not statistically different for intervertebral discs, neural foramina and ligaments, while significantly lower or not statistically different for soft tissues and vertebrae. The overall image quality scores were significantly higher with IR compared with FBP, and with LD-IR compared with SD-FBP. LD-IR cervical spine CT provides better image quality for intervertebral discs, neural foramina and ligaments, and worse image quality for soft tissues and vertebrae, compared with SD-FBP, while reducing radiation dose by approximately 40 %.

Single vertebral registration method for minimally invasive spine surgery robot

For minimally invasive spinal surgical robot, preoperative images and intraoperative image registration technology is the core. Image registration is intended to show the trajectory of preoperative planning images into intraoperative image, and also show the relative position of the surgical instruments and trajectory of preoperative planning. As the physiological curve, anatomical structure of the spine and the intervertebral discs and ligaments, the entire spine can be treated as a deformable structure. Simultaneously, the different capture angle of the preoperative images and intraoperative image will also lead to the registration errors. Therefore, this paper proposes a method based on SIFT operator and multi-angle search for a single vertebra. This method is realized in the preoperative and intraoperative image registration on the anteroposterior and lateral view. For the verification of the registration results, we use opre-implantation Kirschner, and the algorithm based on point to point to verify the registration method. As the validation error point-based on Kirschner wire exists a certain space limitations, another verification method, Harris corner error validation method could compensate this limitation. By detecting the Harris corner in preoperative and intraoperative image, we calculate the multi-point based error to validate the registration method, the errorsare all less than 1 mm. It is acceptable for laboratory examination and clinical application.

Fracture of the Atlas through a Synchondrosis of Anterior Arch

Cervical fractures are rare in paediatric population. In younger children, cervical fractures usually occur above the level of C4; whereas in older population, fractures or dislocations more commonly involve the lower cervical spine. Greater elasticity of intervertebral ligaments and also the spinal vertebrae explains why cervical fractures in paediatric ages are rare. The injury usually results from a symmetric or asymmetric axial loading. In paediatric cases, most fractures occur through the synchondroses which are the weakest links of the atlas. The prognosis depends on the severity of the spinal cord injury. In this case, we presented an anterior fracture in synchondrosis of atlas after falling on head treated with cervical collar. There was no neurologic deficit for the following 2 years.

Intervertebral disc as a source of pain

Back pain, although not usually life threatening, is a major public health problem both here in the UK and in Western societies in general. It affects a large number of people each year and is a cause of considerable economic loss and personal suffering. Point prevalence rates indicate that it affects between 12% and 35% of the population, of whom 20% will seek medical attention. One study in the UK estimated that in 1998, direct health-care costs associated with back pain were approximately £1.6 billion, but the total costs related to lost productivity closer to £11 billion. 2 A number of anatomical structures within the back may be responsible for back pain; intervertebral discs, facet joints, muscles, ligaments, and nerve root sheaths are all possible ‘pain generators’. Of these, the intervertebral discs, facet joints, and sacroiliac joints are implicated in up to 45, 40, and 13% of the cases, respectively. Furthermore, more than one structure may be contributing to the pain at any one time. The intervertebral disc may produce pain either as a result of intrinsic degeneration (discogenic pain) or by extrinsic compression of neural structures in the spinal canal, producing radicular pain. Disc degeneration also results in loss of disc height which, in turn, may alter the mechanics of the axial skeleton. These changes may produce pain in other structures including the zygapophyseal (facet) joints and may ultimately result in spinal stenosis. Discogenic pain is defined as axial pain originating in a degenerative disc. Radicular pain is the pain radiating in the distribution of a spinal nerve caused by the irritation of the sensory root or dorsal root ganglion (DRG) of that spinal nerve.Although degenerative disc disease (DDD) is the most common cause of such compression, there are other pathologies which may produce radicular pain.

Flexural–torsional buckling initiates idiopathic scoliosis

Initiation of the spinal deformity in idiopathic scoliosis (IS) has been attributed to an abnormal pattern of spinal growth during development. However, recent findings suggest that the earliest observable event in the pathogenesis of IS is a change in the shape of intervertebral discs with alterations in the shape of vertebrae being considered a secondary event. Starting from the previous description of the spinal deformity in IS as ‘buckling’ of the spine a new hypothesis describing the initial spinal deformity in IS as flexural–torsional buckling, a three-dimensional type of failure of axially loaded columns, is proposed. According to the new hypothesis the initiating event (the earliest observable event) in IS is flexural–torsional buckling developing from the flexible parts (intervertebral discs and ligaments) of the affected spinal motion segments. Since flexural–torsional buckling occurs in columns with a cross-section of one axis of symmetry characterised by a much greater in-plane than out-of-plane bending stiffness the new hypothesis predicts that the initiating condition (the condition promoting the initiation) of IS is ‘flexibility anisotropy’ namely significantly higher bending stiffness in lateral bending than bending stiffness in flexion–extension of a part of the spine. The parameter of ‘flexibility anisotropy’ as a factor for initiation of IS has never been suggested or tested before. The present hypothesis has implications in the research on the pathogenesis of IS as well as in the development of new methods for its treatment.

Surgical Versus Nonsurgical Treatment of Selected Patients With Discogenic Low Back Pain

Low back pain (LBP) is a common clinical problem and is of major socioeconomic importance. Although any of the spinal structures (intervertebral discs, facet joints, vertebral bodies, ligaments, and muscles) may be a source of LBP, the most likely cause is a lumbar intervertebral disc.1–3 Many autho

Thoracic and lumbar intraforaminal ligaments

The author conducted a study to investigate the anatomy of the intraforaminal ligaments of the thoracic and lumbar nerve roots and describe their anatomical relationships and functional properties. This anatomical study performed on the intervertebral foramina, intraforaminal ligaments, transforaminal ligaments, and nerve roots of the thoracic and lumbar spine was performed in human cadavers. The foraminal anatomy was studied in 11 whole cadavers (5 females, 6 males) previously prepared with formaldehyde, whose ages at the time of death ranged from 16 to 71 years. The thoracic and lumbar spinal columns were separated from the cervical and sacral segments en bloc using an electric band saw. The paraspinal muscles and their attachments were removed by sharp and meticulous dissection, and the thoracic and lumbar intervertebral foramina were examined under a surgical microscope. The intervertebral foraminal ligaments and nerve roots were exposed. The foraminal contents were identified and studied in detail. The intraforaminal ligaments were stained using H & E to determine ligamentous fiber. Intraforaminal ligaments connect the periosteum and transforaminal ligaments to the nerve root sleeves and vessels within the fatty areolar tissue. Histologically, the ligamentous attachment of the nerve roots within the foramina consists of adipose and connective tissue. The nerve roots are surrounded by intraforaminal ligaments, which may act in conjunction with the dura and periosteum to protect the nerve roots mechanically.

Production of Wnt4b by floor plate cells is essential for the segmental patterning of the vertebral column in medaka

The floor plate is a key organizer that controls the specification of neurons in the central nervous system. Here, we show a new role of the floor plate: segmental pattern formation of the vertebral column. Analysis of a spontaneous medaka mutant, fused centrum (fsc), which exhibits fused centra and the absence of the intervertebral ligaments, revealed that fsc encodes wnt4b, which was expressed exclusively in the floor plate. In fsc mutants, we found that wnt4b expression was completely lost in the floor plate and that abnormal conversion of the intervertebral ligament cells into osteoblasts appeared to cause a defect of the intervertebral ligaments. The establishment of the transgenic rescue lines and mosaic analyses allowed the conclusion to be drawn that production of wnt4b by floor plate cells is essential for the segmental patterning of the vertebral column. Our findings provide a novel perspective on the mechanism of vertebrate development.

Vertebral fractures in the elderly may not always be “osteoporotic”

Introduction Vertebral fractures in the elderly are often assumed to be “osteoporotic” and require anti-osteoporosis therapy. However, some of these fractures may represent traumatic injuries to vertebrae that have comparatively normal bone mineral density (BMD). We hypothesize that radiographic appearances can be used to differentiate between “osteoporotic” fractures of vertebrae with low BMD and strength, and “traumatic” fractures of vertebrae with normal BMD and strength. Methods 73 cadaveric specimens (each comprising two vertebrae with the intervening intervertebral disc and ligaments) were obtained from donors aged 42 to 91 (mean 74) years. Areal BMD was measured in the lateral projection for each vertebral body, using DXA. Each specimen was secured in metal cups containing dental plaster, and compressed to failure at 3 mm/s on a computer-controlled materials testing machine. Mechanical failure was detected by a reduction in the gradient of the load-deformation curve. Compressive deformation for each specimen was limited to 4 mm in order to prevent gross destruction of the vertebra. Radiographs, obtained before and after mechanical loading, were assessed by an experienced radiologist (GJ) who was blinded to BMD and mechanical data. The algorithm-based qualitative method (ABQ) was used to assign each specimen to two possible outcomes: no discernible fracture of either vertebra, or fracture. The latter were further classified into specimens with osteoporotic fracture and those with traumatic fracture, by applying additional criteria for differential diagnosis. The relationship of failure load to BMD was tested using correlation. BMD and failure load for the three diagnostic outcomes were compared using one-way analysis of variance (ANOVA). Results Failure load was proportional to BMD ( R = 0.63, p < 0.001). “Osteoporotic,” “traumatic” and “no discernible” fractures were reported in 16, 26 and 31 specimens respectively. “Traumatic” fracture specimens had higher BMD and failed at higher loads than “osteoporotic” fracture specimens ( p < 0.05). Conclusions Some vertebral fractures in the elderly may be traumatic rather than osteoporotic in origin. Our radiological criteria help to differentiate between them.

Preliminary Results of a Randomized, Equivalence Trial of Fluoroscopic Caudal Epidural Injections in Managing Chronic Low Back Pain: Part 1 — Discogenic Pain without Disc Herniation or Radiculitis

Background: Intervertebral discs, facet joints, ligaments, fascia, muscles, and nerve root dura have been described as tissues capable of transmitting pain in the low back. The pathophysiology of spinal radicular pain is the subject of ongoing research and controversy with discogenic pain assuming a major role as a cause of non-specific low back pain. Even though epidural injections are frequently administered in managing axial low back pain, the evidence is lacking. Study Design: A randomized, double-blind, equivalence trial. Setting: An interventional pain management practice, a specialty referral center, a private practice setting in the United States. Objectives: To evaluate the effectiveness of caudal epidural injections with or without steroids in managing chronic low back pain without disc herniation or radiculitis in providing effective and longlasting pain relief and to evaluate the differences between local anesthetic with or without steroids. Methods: Patients were randomly assigned to one of 2 groups, Group I patients received caudal epidural injections with local anesthetic (lidocaine 0.5%), whereas Group II patients received caudal epidural injections with 0.5% lidocaine 9 mL mixed with 1 mL of steroid. Randomization was performed by computer-generated random allocation sequence by simple randomization. Outcomes Assessment: Multiple outcome measures were utilized which included the Numeric Rating Scale (NRS), the Oswestry Disability Index 2.0 (ODI), employment status, and opioid intake with assessment at 3 months, 6 months, and 12 months post-treatment. Significant pain relief was defined as 50% or more, whereas significant improvement in disability score was defined as reduction of 40% or more. Results: Significant pain relief (≥ 50%) was demonstrated in 72% to 81% of patients and functional status improvement was demonstrated by a reduction of 40% in the ODI scores in 81% of the patients. The overall average procedures per year were 3.6 ± 1.05 in Group I and 3.9 ± 1.33 in Group II with an average total relief per year of 32.3 ± 16.93 weeks in Group I and 30.7 ± 17.94 weeks in Group II over a period of 52 weeks. Limitations: The results of this study are limited by lack of a placebo group and a preliminary report of 36 patients in each group. Conclusion: Caudal epidural injections with or without steroids may be effective in patients with chronic function-limiting low back pain without facet joint pain, disc herniation, and/or radiculitis in over 70% of the patients. Key words: Chronic low back pain, caudal epidural injections, discogenic pain, disc herniation, radiculitis, local anesthetic, steroids, controlled comparative local anesthetic blocks, provocation discography

MECHANISMS FOR MECHANICAL DAMAGE IN CERVICAL LIGAMENTS DURING WHIPLASH. A 3D FE STUDY

Whiplash injury is a frequent mechanism for chronic neck pain and accounts for half of all patient-care expenses from motor vehicle accidents [Quinlan et al., 2004]. Damage to the cervical spine can be classified according to the neck movement and the mechanical loads. The most frequent consequence of traffic accidents consists in damage to the soft tissues, that means, intervertebral discs, ligaments and muscles. The intervertebral ligaments are the key to spinal stability; if they are stretched or torn during a car crash, a myriad of symptoms can result. Previous in vitro biomechanical studies have investigated potential neck ligament injuries due to whiplash (Pearson et al., 2004). Lastly, Panjabi et al. (2006) applied quasi-static physiological loading to cervical spine specimens prior to and following rear impacts and documented injuries at the middle and lower cervical spine and increased injury risk due to rotated head posture at the time of impact, but injuries to specific ligaments were not identified. In this work, we used a finite strain anisotropic damage model for fibred soft tissues to predict the mechanisms for mechanical damage in the cervical ligaments during whiplash.

Chronic Back Pain Secondary to a Calcified Epidural Blood Patch

Chronic Back Pain Secondary to a Calcified Epidural Blood Patch

Chance Fracture - A Rare Injury in Pediatric Patients?

We report on a 9-year-old girl who was involved in a car accident. She suffered severe polytrauma with torn abdominal muscles, rupture of the mesenteric arteries, bowel and bladder, hematoma at the right colonic flexure and disruption of the intervertebral ligaments L2/L3, including the intervertebral disc, typical of Chance fracture. The abdominal bleeding was stopped, the bowel resected and the fracture fixed by internal fixation. The patient developed a postoperative enterocutaneous fistula in the right flank and paraplegia. She underwent three laparotomies with ileostomy and closure of the fistula. Two years later, she has normal bowel movement, the wounds are closed, the internal fixation has been removed, she is able to walk with crutches and suffers from a mild bladder dysfunction. Chance fracture is a typical fracture in adults involved in motor vehicle accidents. In the last 10 years, there have only been four case reports describing this fracture in children under the age of 10. All of these individuals were involved in a car accident and had been fixed with a lap belt. With the increasing use of lap belts, this fracture has to be considered even in young children. Mild clinical symptoms can be associated with severe intra-abdominal injuries.

The salmon vertebral body develops through mineralization of two preformed tissues that are encompassed by two layers of bone.

The teleost backbone consists of amphicoelous vertebrae and intervertebral ligaments, both of which include notochord-derived structures. On the basis of a sequential developmental study of the vertebral column of Atlantic salmon (Salmo salar L.) from the egg stage up to early fry stage (300-2500 day-degrees) we show that the vertebral body consists of four layers or compartments, two of which are formed through mineralization of preformed collagenous tissue (the notochordal sheath and the intervertebral ligament) and two of which are formed through ossification. The three inner layers have ordered lamellar collagen matrixes, which alternate perpendicularly from layer to layer, whereas the outer layer consists of cancellous bone with a woven matrix. The bone layers also differ in osteocyte content. In this study we describe the structural details of the layers, and their modes of formation. The results are compared with previous descriptions, and possible phylogenetic implications are discussed.