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Published in Clare E. Milner, Functional Anatomy for Sport and Exercise, 2019
The lumbar spine is the distal end of the mobile portion of the vertebral column. The vertebral bodies are large and strong and the articular facets are oriented obliquely to prevent intervertebral rotation movements. The lumbar spine has a large flexion-extension range of motion and is supported by the common longitudinally running ligaments of the vertebral column (see thoracic region – ligaments). The strong and wide anterior longitudinal ligament runs the length of the vertebral column and is attached to the anterior surface of the vertebral bodies and intervertebral discs; it helps to prevent hyperextension of the vertebral column. The thinner and weaker posterior longitudinal ligament is attached to the posterior surface of the intervertebral discs and lies inside the vertebral canal. The posterior wall of the vertebral canal is formed by the ligamentum flavum, which connects adjacent vertebral arches at the laminae. The remaining ligaments connect the various processes of the vertebrae. The interspinous ligaments lie between adjacent spinous processes and weakly connect them. The strong supraspinous ligament connects the tips of the spinous processes and helps to prevent hyperflexion. There are also thin and weak intertransverse ligaments in the lumbar region which connect adjacent transverse processes.
Neuropathic Low Back Pain
Published in Gary W. Jay, Practical Guide to Chronic Pain Syndromes, 2016
Joseph F. Audette, Walker Joseph, Alec L. Meleger
Paraspinal entrapment, a less-recognized clinical entity, has been suggested and reported in several studies and case reports. One large cadaveric study found a relatively frequent, age-related occurrence of an ossified mamillo-accessory ligament leading study authors to consider the possibility of entrapment neuropathy involving the medial branch of the dorsal ramus, which passes underneath this ligament (11). Lumbar nerve root compression by a combination of an intertransverse ligament and a vertebral osteophyte has been reported in one case as well.
Endoscopic Surgery and Minimally Invasive Techniques
Published in Mark V. Boswell, B. Eliot Cole, Weiner's Pain Management, 2005
Anthony T. Yeung, Christopher Alan Yeung
Discogenic pain as determined by evocative discography may implicate the disc as a pain generator. Symptomatic disc herniation is the obvious indication, with surgical decompression limited only by the accessibility of endoscopic instruments to the herniated fragment.9,10 Because of the posterolateral foraminal approach, the ideal lesion for endoscopic discectomy is a far lateral, extraforaminal disc herniation. Traditional approaches to far-lateral, extraforaminal disc herniations are more difficult, requiring a paramedian incision through the vascular intertransverse ligament. This surgical area is often called the “hidden zone” for traditional surgeons. Although a traditional spinal surgeon can access the lateral zone of the disc with a paramedian incision, it is easier to access the extraforaminal zone endoscopically via the posterolateral portal. A typical foraminal view of nucleus pulposus extruded past the posterior annulus is shown in Figure 73.4. With this approach to the disc, relatively easy access is possible from T–10 to L5 (Figure 73.2b). This is also the preferred approach for disc herniations in the upper lumbar and lower thoracic spine because the transcanal approach will require more extensive laminectomy that may destabilize the spinal segment if the herniation is above L3–L4.
A comparative finite element analysis of artificial intervertebral disc replacement and pedicle screw fixation of the lumbar spine
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Jayanta Kumar Biswas, Anindya Malas, Sourav Majumdar, Masud Rana
The bone material properties were assumed as linearly elastic and the modulus of elasticity (E) was allocated from CT scan Hounsfield gray values (HU), using Eqs. (1) and (2), which was taken element-wise from MIMICS software (Biswas et al. 2018). A multi-linear stress-strain relation was assigned as material properties for the intervertebral disc (Biswas et al. 2018). Seven several ligaments, (1) posterior longitudinal ligament (PLL), (2) anterior longitudinal ligament (ALL), (3) facet capsulary ligament (FCL), (4) supraspinous ligament (SSL), (5) ligamentum flavum (LF), (6) intertransverse ligament (ITL) and (7) interspinous ligament (ISL) were considered and the material properties were taken from literature as given in Table 1 (Rana et al. 2020). Titanium (Ti6Al4V) alloy was considered for screw and endplate of the artificial disc for which modulus of elasticity (E) = 115 GPa and Poisson’s ratio (ν) = 0.35 (Bhattacharya et al. 2019). The core (middle part) of the artificial disc was made of UHMWPE for which modulus of elasticity (E) = 690 MPa and ν = 0.45 (Bhattacharya et al. 2019). The connecting rod is made of CFR-PEEK having E = 18,000 MPa and ν = = (Kang et al. 2017).
Biomechanical analysis of segmental lumbar lordosis and risk of cage subsidence with different cage heights and alternative placements in transforaminal lumbar interbody fusion
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Sajjad Rastegar, Pierre-Jean Arnoux, Xiaoyu Wang, Carl-Éric Aubin
A detailed finite element model (FEM) of L4-L5 functional spinal unit was created based on a previously developed and validated FEM of the spine (El-Rich et al. 2008; El-Rich et al. 2009) (Figure 1(a)). The FEM was adapted and refined to simulate the biomechanics of the TLIF, including intervertebral space preparation, cage insertion, and posterior fixation (Agrawal and Resnick 2012; Gum et al. 2016). The geometric model of the spine was reconstructed using medical images acquired through a CT-scan (0.6 mm slice thickness) of a 50th percentile healthy man (El-Rich et al. 2008; El-Rich et al. 2009). The model consisted of the vertebral body (cancellous and cortical bones), posterior arches, intervertebral disc, facet joints and seven ligaments, i.e. the anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), ligamentum flavum (LF), capsular ligaments (CL), intertransverse ligament (ITL), interspinous ligament (ISL) and supraspinous ligament (SSL) (Figure 1(a)).
Sensitivities of lumbar segmental kinematics and functional tissue loads in sagittal bending to design parameters of a ball-in-socket total disc arthroplasty prosthesis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
The spine mechanical behavior is significantly influenced by the material properties of soft tissues, such as intervertebral discs and spinal ligaments. Thus, they were carefully modeled and calibrated, such that the resulting kinematic responses of both individual tissues and the entire lumbar spine matched published in vitro measurements. Heuer et al. (2007) measured the mechanical responses of each spinal tissue in eight L4–5 segment specimens in extension, flexion, lateral bending and axial torsion, by a step-wise reduction procedure of functional spine structures from the posterior to the anterior. In the previous experiment, the intertransverse ligament (ITL) was missing in most specimens and therefore not considered (Heuer et al. 2007). These defected segments with sequentially reduced spinal tissues were applied pure moments ramping up to 10 N m in each loading scenario, and the resulting kinematical responses of segments were measured.