The spine is host to a wide range of afflictions causing an array of neurologic and musculoskeletal symptoms. Frequent etiologies encountered by hospital neurologists include degenerative spine disease, infection, autoimmune, and neoplastic, in addition to several spine emergencies. Degenerative diseases of the spine include cervical and lumbar disc herniations causing radiculopathy, axial back pain, and neurogenic claudication. Spondyloarthropathies, particularly ankylosing spondylitis and rheumatoid arthritis, infection, and neoplastic diseases should be well known. Spine emergencies including spinal canal hematomas, cauda equina syndrome, and conus medullaris syndrome should be promptly diagnosed with appropriate imaging and prompt neurosurgical evaluation.
Cervical herniated nucleus pulposus
Cervical disc herniation or cervical herniated nucleus pulposus (HNP) occurs as a result of dehydration and fragmentation of the nucleus pulposus (NP).1 As the body ages, hydrophilic proteoglycan molecules in the NP undergo degenerative biochemical changes that lead to decreased viscoelasticity.2 Eventually disc height is lost and the axial load exerted by the body above is translated to the annulus fibrosus, which then thins and fibroses. In chronic HNP, the fibrotic nuclear material stays within the lamellae without penetrating the annulus. However, due to the lamellae being weak, the disc material can dissect through the attachment of the Sharpey’s fibers to the bony edges of the vertebral bodies, leading to reactive bone growth and osteophyte formation.3,4
All discs are dependent on blood diffusion from capillary beds in the vertebral body endplates to acquire nutrients and dispose of metabolites. Chronic hypoxia to the cells of the NP causes its cells to become quiescent, whereas chronic hypoglycemia causes their death.5 These processes occur as a natural part of aging but can also occur due to environmental factors as well as genetic predisposition. The latter has been shown to be implicated in 34–61% of cases depending of the level of disc disease.6,7
In more acute scenarios of HNP, the nuclear material actually dissects through a failed annulus and often the posterior longitudinal ligament (PLL) as well.
A HNP can compress the spinal cord or adjacent nerve rootsat the foramen level. Acute HNP occurs more often in a lateral direction due to the relative weakness of the PLL in this location. Therefore, acute HNP is more likely to cause nerve root compression as opposed to spinal cord compression.1
Acute disc herniations can cause axial neck pain or a more classic radicular pain.2 Axial neck pain is due to the significant innervation of the anterior and posterior aspects of the annulus by the sympathetic trunk/recurrent branches of gray rami communicants and the sinuvertebral nerves, respectively. Radiculopathy may be acute or chronic. Acute radiculopathy manifests as severe pain, and is usually due to a soft disc herniation and occurs in younger patients. ...