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Spinal Cord Disease
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Nondegenerative process: Congenital central spinal stenosis.Hypertrophic ligamentum flavum.Posterior longitudinal ligament ossification.Epidural lipomatosis.
Neuroanatomy: Age-related changes
Published in Hemanshu Prabhakar, Charu Mahajan, Indu Kapoor, Essentials of Geriatric Neuroanesthesia, 2019
The segmental instability due to disc degeneration increases the load on the facet joints, leading to their subluxation and cartilage degradation. Spinal canal stenosis may be caused by facet hypertrophy, osteophyte formation, and apophyseal malalignment. Degenerative spondylolisthesis may occur due to destabilization of the joint. The ligaments surrounding the spine become increasingly weak due to chemical and macroscopic changes with age. The degeneration of ligamentum flavum leads to its increased thickness and bulging. All these factors further contribute to spinal stenosis, and if present in the cervical spine, may progress to myelopathy (27).
Biomechanics of the Spine
Published in Manoj Ramachandran, Tom Nunn, Basic Orthopaedic Sciences, 2018
Amir Ali Narvani, Arun Ranganathan, Brian Hsu, Lester Wilson
In the lumbar region, the facets are oriented at right angles to the transverse plane and at 45° to the frontal plane. This permits flexion, extension and lateral flexion but no rotation. The facets and the discs have a coupled function in load bearing. The disc is loaded in flexion and the facets take more than 30% of the load in hyperextension. Spinal ligaments are static stabilizers of the spine. All spinal ligaments except the ligamentum flavum have high collagen content, and this limits their extensibility during spinal motion. The ligamentum flavum primarily attaches to the posterior arches of adjacent vertebrae. It is rich in elastin content and hence contracts in extension and expands in flexion. This also helps maintain spinal canal dimensions during motion. The ligaments farthest away from the centre of rotation bear the maximum stress and maximally limit the motion. Thus the anterior longitudinal ligament is maximally stressed in extension, the interspinous and supraspinous ligaments in forward flexion and the transverse ligaments in lateral flexion. The range of flexion gradually increases in the lumbar motion segments and reaches 20° at L5–S1. Lateral flexion is limited to about 30° in the lumbar spine. Lateral rotation is 20° in the upper lumbar spine and increases to 50° in the lumbosacral junction.
Factors associated with the recurrence of lumbar disk herniation: biomechanical–radiological and demographic factors
Published in Neurological Research, 2022
Anas Abdallah, Erhan Emel, Betül Güler Abdallah
To standardize surgery, the surgeons (EE and AA) attended all procedures at the same institute. In the prone position, fluoroscopy was used to detect the operative level. For a conventional microdiscectomy, regarding the operative level, a 1.5–2 cm incision was performed at the midline. Subperiosteal dissection of the muscles was performed in appreciating the compatibility of the supra- and interspinous ligaments. A partial hemilaminectomy of the superior vertebra was performed using a high-speed drill or Kerrison rongeurs under a white-light microscope. The ligamentum flavum (LF) was removed. The posterior longitudinal ligament and annulus fibrosus were incised, and the disk material was removed. To reduce the risk of re-herniation with new fragments, the diameter of the incision at the annulus fibrosus was kept at <5 mm. In cases with annular fissures >5 mm, these fissures were used without enlarging them [36]. Hemostasis was performed after resecting the cartilaginous endplates of the herniated disks and the free-floating disk fragments (i.e. an aggressive discectomy [37] was applied to all patients). In a macro discectomy, the same steps were performed, but a microscope was not used. The skin incision was made up to 3 cm.
Efficacy of interspinous device on adjacent segment degeneration after single level posterior lumbar interbody fusion: a minimum 2-year follow-up
Published in British Journal of Neurosurgery, 2021
Kwang Ryeol Kim, Chang Kyu Lee, In Soo Kim
All patients underwent L4/5 PLIF. Fourteen patients received concomitant DIAM implantation on L3/4 (Group A) while 37 underwent only L4/5 PLIF (Group B). PLIF procedures included laminectomy, medial facetectomy, excision of ligamentum flavum and discectomy followed by interbody fusion by autograft for 41 patients and PEEK cage for 10 patients with iliac bone graft and rigid pedicle screw fixation. In Group A, the DIAM implant was placed between spinous processes after the interspinous ligament was removed at the adjacent rostral level. The supraspinous ligament was preserved. If the ligamentum flavum was hypertrophied, it was removed to prevent compression of the thecal sac. It was unnecessary to extend skin incisions in Group A. The implant size was determined by inserting template trials (8, 10, 12 and 14 mm). The implant was firmly anchored in place using two tethers passing around two adjacent spinous processes. These tethers were secured to the implant by crimps (Figure 1).
Bilateral laminotomy through a unilateral approach (minimally invasive) versus open laminectomy for lumbar spinal stenosis
Published in British Journal of Neurosurgery, 2021
Jack Horan, Mohammed Ben Husien, Ciaran Bolger
The patient is positioned in the prone position under general anaesthesia. Local anaesthesia and epinephrine are injected into the incision site. An incision over the midline is performed on the side that is more symptomatic. The retractor is then placed. Correct position of the retractor is confirmed by fluoroscopy. The microscope is brought in and the ipsilateral lamina is viewed. An ipsilateral hemilaminectomy is performed using a high-speed drill bit. The spinous process and contralateral lamina are then undercut and drilled, enabling visualization and access to the contralateral side. The ligamentum flavum is identified. It is left in situ during removal of the contralateral bone as it serves to protect the dura during this stage of bone removal. Following the removal of contralateral bone the ligamentum flavum is then removed. When adequate decompression is achieved, the retractors are removed with care and the incision is closed.