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British Medical Books Health Issues Computerized Tomography

Definition

  • a combination of degenerative disc disease & osteophyte formation
  • typically begins at age 40-50
  • seen in men > women
  • most common occurs at C6-7 > C5-6 levels
  • risk factors include frequent lifting, smoking & driving
  • may lead to myelopathy, radiculopathy, or both

Pathoanatomy

Osteophytosis

  • bony spurs or ridges - osteophytes
  • occurs as result of breakdown in the annular fibers of annulus fibrosus
  • disk material stretching & displacing these fibers, causing stress at ligamentous attachments leading to formation of osteophytes
  • osteophytes initially extend horizontally, later on vertically from edges of vertebra, sometimes bridging disk space
  • involves the disc, two facet joints & two false uncovertebral joints(Lushka)
  • cervical cord becomes impinged when diameter of canal (normally about 17 mm) reduced to less than 13 mm

Hyperextension

  • cord & roots are pinched between discs and adjacent osteophytes anteriorly, and hypertrophic facets and infolded ligamentum flavum posteriorly

Hyperflexion

  • cord narrows & the neural structures are tethered anteriorly across discs or spondylitic bars

Radiculopathy

  • spondylotic changes in the foramina primarily from chondro-osseous spurs of the joints of Luschka may restrict motion and may lead to nerve root compression

Disk herniation

  • usually posterolateral, between posterior edge of uncinate process & lateral edge of posterior longitudinal ligament
  • resulting in acute radiculopathy

Myelopathy

  • central herniation
  • spondylotic bars with a congenitally narrow canal

Apophyseal joints

  • show early irregularity & blurring of the joint surfaces
  • joint space narrowing & eventual spurring & sclerosis
  • lateral & oblique view
    • allows evaluation of facet joints
    • determine if osteophytes of apophyseal joints project medially into foramina canal
  • osteophytes arising from the ventral portion of superior articular process may cause symptomatic foraminal narrowing
  • rarely osteophytes may project anteriorly and impinge upon vertebral artery, resulting in arterial insufficiency
  • loss of disk height leads to reduced neuroforaminal volume –> root more susceptible to compression

Joints of Luschka

  • symphysis type of articulation between vertebral bodies
  • joints give rise to bony spurs - as can main facet joints & edges of vertebral bodies
  • exiting N root on each side travels between these joints, & can be compressed by osteophytes extending into intervertebral foramen from any or all three of sources

Differential Dg.

  • Stroke / TIA
  • Multiple sclerosis
  • Thoracic outlet sy.
  • Pancoast Tumors
  • RSD
  • Brachial neuritis (upper & lower motor neurons, sensation is N)
  • Spinal cord tumour
  • Syringomyelia
  • Cerebral hemisphere lesion
  • Low pressure hydrocephalus
  • Herpes Zoster
  • Shoulder impingement, RC tears
  • AS, Reiter’s dx. or DISH
    • occurance of bony ankylosis found in spodylosis involve only 1 or 2 levels

Clinical

Signs and Symptoms

Pain

  • early symptom
  • funicular pain
  • characterized by central burning & stinging
  • Lhermitte’s phenomenon - lightening like sensations down back with neck flexion
  • may be ischaemic in origin

Myelopathy

  • characterized by weakness (upper > lower extremity)
  • ataxic, broad based, shuffling gait
  • sensory changes
  • rarely urinary retention
  • myelopathy hand
    • finger escape sign (LF spontaneously abducts d/t weak intrinsics)

Radiculopathy

  • can be associated with myelopathy
  • can involve one or multiple roots
  • symptoms include neck, shoulder & arm pain, paresthesias & numbness
  • findings may overlap - intraneural intersegmental connections of sensory roots
  • lower nerve root at a given level is usually affected
  • 70% by spondylosis (with or without disk protrusion)
  • soft disc protrusion causes radiculopathy in only 20–25% of patients
  • C7 radiculopathy is most common followed by C6 radiculopathy

Spurling’s Manouever

  • mechanical stress, such as excessive vertebral motion, may exacerbate symptoms
  • neck hyperextension with head tilted toward the affected side will narrow the size of the neuroforamen and may exacerbate the symptoms or produce radiculopathy

Shoulder Abduction Relief Test:

  • significant relief of arm pain with shoulder abD, elbow flexion, hand on top of head
  • this sign is more likely to be present with soft disc herniation
  • test is likely to be negative with radiculopathy caused by spondylosis (osteophyte compression)

Neurological examination

Upper Cord Involvement: (cervical radiculopathy / myelopathy)

  C5 C6 C7 C8 T1
Sens: Lat.arm Thumb, IF Mid f. RF, LF Med.arm
Motor: Deltoid Wrtist ext. Triceps,FCR Finger Flex Interossei
  5/5 5/5 5/5 5/5 5/5
Disc: C4-C5 C5-C6 C6-C7 C7-T1 T1-T2
Reflex: Biceps Brachiorad. Triceps None None

Cervical Disc Herniation

  • most frequent at C6-7 level, but occur at C5-6 & to a lesser extent at C4-5 & other levels
  • in relatively younger persons soft disk protrusion is more common than hard disk protrusion

Types of herniation

  • intraforaminal herniation
    • most common type
    • cause predominately sensory changes
  • posterolateral type
    • occurs near entrance zone of foramen
    • causes predominately motor changes
  • central type
    • disc herniation occurs more to the midline (ie posterior herniation)
    • compresses spinal cord in addition to, or instead of the nerve root
    • results in cervical myelopathy

Symptoms

Pain

  • neck pain from nerve root compression
  • radiating into ipsilateral upper extremity with paresthesias, numbness, or weakness
  • may be intensified by neck movement, especially by extension or by lateral flexion to side of herniation, & by coughing or straining

Exam

  • limitation of neck extension
  • Spurling’s sign
  • shoulder abduction relief test
  • lower motor neuron dysfunction
    • muscle weakness & hypotonia
    • reduction of deep tendon reflexes at level of cord compression
  • upper motor neuron dysfunction
    • spasticity, clonus
    • increased deep tendon reflexes
    • Babinski’s sign
  • reduction of sensation below level
  • loss of erection, bladder, & bowel function

Cervical Myelopathy

  • characterized by weakness (upper > lower extremity)
  • ataxic broad based shuffling gait, sensory changes;
  • rarely urinary retention

Anatomy of compression

  • anterior cord compression - protruding disc or posterior osteophytes
  • anterolateral compression - joints of Luschka
  • lateral compression - cervical facets
  • posterior compression - ligamentum flavum

Clinical Findings

  • UMN findings such as hyper-reflexia, clonus, or Babinski’s sign
  • funicular pain, characterized by central burning and stinging
  • Lhermitte’s phenomenon
    • radiating lightening like sensations down back with neck flexion

Jaw jerk

  • performed by the tapping on the slightly opened jaw - controlled by the fifth cranial nerve
  • a normal reflex contraction of the masseter effectively rules out pathology above the foramen magnum

Upper extremity

  • mixed upper and lower motor neuron findings
  • can present with hand dysfunction with loss of fine motor function such as writing

Myelopathy hand

  • finger escape sign - small finger spontaneously abducts d/t weak intrinsics

Inverted radial reflex (C5 - C6)

  • may be present when cord & root compression are present at C5 level
  • demonstrated by tapping brachioradialis tendon
  • diminished reflex noted along with a reflex contraction of spastic finger flexors
  • d/t peripheral compression of C6 nerve root (from disc or spur) which allows UMN reflex to occur

Biceps reflex

  • primarily indicates neurologic integrity of C5
  • the reflex also has a C6 component

Lower extremity

  • UMN signs
  • hyper-reflexia & frank clonus in lower extremities;
  • decline in ability to walk, apparent ataxia
  • loss of lower extremity proprioception

Lhermitte’s sign

  • paresthesias or leg weakness exacerbated by neck flexion
  • shock-like sensation
  • men may be cursed by this as they attempt to urinate

Prognosis

  • condition has high potential for becoming worse leading to severe disability
  • myelopathic symptoms have variable potential for recovery, but prognosis for recovery is better when decompression is performed early

Radiographs

Lateral & oblique views

  • loss of disk height, with subsequent loss of cervical lordosis
  • vacuum phenomena
    • indicates spondylosis
    • erosive changes in the disk & end plates more suggestive of inflammatory lesions
  • anterior osteophytes
    • largest
    • may alter the overall shape of the vertebral body
    • large anterior osteophytes may be suggestive of DISH
  • posterior osteophytes
    • smaller
    • more important clinically –> project into spinal canal
  • stenosis
    • in upright erect lateral view at distance of 6 feet, distance from posterior cortex of vertebral body at its midpoint to laminar line should be approximately 17 mm (SAC)
    • if this distance is narrowed by posterior osteophyte, diameter of 13 mm should begin to raise suspicion of impingement of spinal canal, & diameters of < 10 mm correlate highly w/ cord compression

Flexion-extension views

  • AP subluxation of more than 3.5 mm
  • more than 20 deg of saggital angulation

EMG

  • studies have a high false negative rate
  • may be helpful in select cases for differentiating peripheral nerve lesions from more central compression & disease such as AML

MRI

  • with subtle clinical & x-ray findings consider dynamic MRI (flexion-extension)
  • spinal cord may show increased signal changes on T2 images

CT - Myelogram

  • to localise lesion
  • compression ratio: smallest AP diameter divided by largest transverse diameter

Treatment

Conservative Rx

  • rest
    • collar or braces
    • traction (Halter) controversial
  • analgesia, NSAIDs
  • physio

Surgical

Indications

    • intractable pain - failure of conservative Rx
    • increasing neurological deficit
    • myelopathy

Anterior approach & fusion

  • requires discectomy, removal of posterior osteophytes & removal of bony sclerotic bed of vertebral body
  • fusion of one or more levels is performed by countersinking iliac crest bone graft between vertebral bodies
    • Cloward
    • Smith-Robinson
  • stability of bone graft is achieved by initial distraction of soft tissues as graft is inserted
  • once, distractive force is removed the graft will be held firmly between vertebral bodies
  • may use instrumentation - plates
  • note: to maintain stability the posterior longitudinal ligament should be left intact, if possible
  • in most cases of cervical spondylosis involving one or two levels, the pathology will be anterior and will be reflecting clinically as myelopathy, anterior cord syndrome, or central cord sy.
  • when the primary pathology is mostly anterior, generally the anterior approach should be anterior
  • the one exception to this may be the rheumatoid C-spine

Posterior approach

  • posterior decompression thru’ a hemi-laminectomy
  • smaller operation that takes less time and does not require a bone graft
  • most indicated for far-lateral disc herniation
  • removal of the spinous process & lamina on each side at multiple levels;
  • facet joints
    • resection of > 25 % of facet can result in cervical instability –> posterior fusion should be done