spondylosis

Cervical Spondylosis is a non-specific term describing the morphological manifestations of progressive degeneration of the spine.

SPONDYLO is a Greek word meaning vertebra. Spondylosis generally mean changes in the vertebral joint characterized by increasing degeneration of the intervertebral disc with subsequent changes in the bones and soft tissues.

From the IV to V decade, it is clear that IVD undergoes progressive desiccation, becomes more compressible and less elastic and secondary changes ensue. Although the majority of individuals over 40 years of age demonstrate significant radiological evidence, but only a small percentage develop symptoms. The changes result in neural compression resulting in radiculopathy or compression of the spinal cord resulting in myelopathy. Both the neural and spinal cord compression will result in radiculomyelopathy.

Males predominate for myelopathy. There is no such proclivity for disc disease.

Etiology and pathophysiology:

The primary event is a progressive decrease in the degree of hydration resulting in loss of disc height, disc fibrosis and annular weakening. The extra mobility between adjacent vertebral areas probably results in osteophyte formation. Though osteophyte formation may be the body’s attempt to stabilize the joints, their growth can result in narrowing of the spinal canal and cord compression.

There are several predisposing factors, which may cause acceleration of these changes.

(1) Occupations requiring repetitive motion of the cervical spine.

(2) Previous injury with fracture or disc prolapse

(3) Segmentation defects like hemivertebra or fused vertebrae.

The various factors that play a role in spondylitic myelopathy are

1) Congenital narrowing of the cervical spinal canal can be a major cause of myelopathy.

It may be localized or generalized .

Myelopathy is often seen when canal sagittal diameter is 12 mm or less.

2) Acquired narrowing may be due to

(a) osteophytes

can also cause root sleeve fibrosis due to irritation.

(b) ossified posterior longitudinal ligament (OPLL)

a well recognized cause in Japan;

may be related to Diffuse Idiopathic Skeletal Hyperostosis (DISH). Fluorosis may play a part in India;

this heterotopic bone is fragile and the dura may be adherent to this fragile bone and at risk

during surgery.

may result in foraminal stenosis and compression of the root and radicular artery additionally.

(d) hypertrophied ligamentum flavum

may compromise the cord during extension.

3) Dural adhesions to the posterior longitudinal ligament and the root sleeves make the cord

more susceptible to injuries.

4) Vascular compromise by compression of the anterior spinal and radicular arteries and veins may

be responsible for ischaemia of the cord and not improve with surgery.

Clinical features:

Neural compression syndromes are

radiculopathy,

myelopathy or

radiculomyelopathy.

They can be acute, sub-acute, or chronic and occasionally acute exacerbation of chronic symptoms can occur.

Radiculopathy refers to symptoms and signs of nerve root compression such as shooting pain down the arm, “pins

and needles” to frank sensory and motor deficits and absence of reflex corresponding to the nerve root involved. There is

also frequently referred pain and tenderness along the medial border of the scapula and in about 60% of patients there

is occipital headache due to muscle spasm.

The commonest roots affected are C5 and C6.

Myelopathy has been classified in various ways and depends on the involvement of the lateral or medial cord or vascular

involvement. The signs may be a mixture of upper motor neuron signs in the lower limbs and lower motor neuron signs in

the upper limbs and may simulate MND or syringomyelia.

Occasionally the presentation may be that of Brown-Sequard syndrome.

Bladder involvement is unusual.

Combination of radicular and cord symptoms are found in radiculomyelopathy.

Various autonomic symptoms can be produced, such as vertigo, flushing, tinnitus and visual blurring.

These may be mediated by the sympathetic contribution to the sinveretebral nerves from the stellate ganglion.

Vertebro basilar insufficiency due to spondylitic compression of the vertebral artery is uncommon, though popularly diagnosed.

Investigations:

The mainstay of imaging is plain X-Rays and MRI.

Plain X-Rays reveal narrowed disc space, and anterior and posterior marginal lipping of the vertebral bodies. Loss of cervical lordosis is an early finding. Spinal cord narrowing correlates with myelopathy.

Neurophysiologhical studies (EMG and nerve conduction studies) can be used when the diagnosis is in doubt. Carpal tunnel syndrome, thoracic inlet syndrome, amyotrophic lateral sclerosis may be accurately diagnosed by neurophysiological studies.

MRI is the preferred modality. Apart from clearly delineating the soft tissue and disc compression it may show signal intensity changes in the cord itself and helps to assess the degree of cord damage.

Medical management:

Medical Management mainly targets pain relief. Radiculopathy improves in majority without the need for surgery. Commonly used drugs are the NSAIDs and muscle relaxants. The antidepressants may be useful if functional overlay is marked.

Physiotherapy:


MRI-C-5/C-6 Disc prolapse	MRI-Posterior osteo phytes

MRI-OPLL ( saggital )	MRI-OPLL ( Axial )

Physiotherapy has an important role adjuvant to medical or surgical treatment. The main objectives are to decrease the duration of disability, to reduce the use of drugs and to prevent chronicity and recurrence. Active modalities such as exercises for the neck, shoulder and the limbs are preferred.

Passive modalities such as heat, cold, ultrasound, cervical collar, traction, interferential therapy, etc should be used only temporarily as an adjunct.

Manipulation should be avoided.

Surgery: Click for intraoperative video clippings

It is indicated when

1. There is progressive cord dysfunction,

2. In acute cord compression,

3. Persistent pain not responding to conservative measures and interfering with normal life.

Two surgical approaches, anterior and posterior, are available.

With better imaging and use of surgical microscope, anterior approach are now used in majority of cases because it is simple and allows early postoperative mobilization and shorter hospitalization. In addition, the primary pathology such as disc, and osteophytes are dealt with directly.

A left sided approach avoids injury to the recurrent laryngeal nerve injury.

On occasions, such as OPLL it may require drilling of the vertebral body (corpectomy) for adequate decompression. Visualization of the posterior longitudinal ligament and a possible tear, and exploration of the same for extruded disc fragments is an important step .The presence of such extruded disc fragments may be suggested by a careful study of the MRI pictures.

When multiple levels (more than two) are involved many advocate fusion in addition to discectomy. Various techniques are available.

When root pain is the predominant symptom a fusion to prevent narrowing of the intervertebral foramen is recommended.

A tricorticate graft obtained from the posterior iliac crest so that its cancellous part lie against the subchondral bone above and below the space, while its cortical part forms the support between the vertebrae (Smith Robinson Technique) is commonly used.

Attempts to take a graft from the anterior iliac crest may injure the lateral cutaneous nerve of the thigh.

The drilling the adjacent vertebral surfaces, after removing the cartilaginous plates, helps in fusion.

The Cloward's technique, using a bone dowel is also popular.

Simmon's technique involves making a keystone square in the adjacent vertebral bodies for the graft.

Bailey and Badgley technique involves making a rectangular trough in the adjacent bodies for the graft.

Cadaveric bone grafts and methyl methacrylate are used by some for obvious reasons, but autografts have been found superior .

Some advocate suturing the prevertebral fascia over the graft to prevent graft migration.

Some advocate anterior instrumentation in addition to bone grafting, especially in cases where trauma is a factor. Anterior self locking plate fixation is common. Titanium cage filled with cancellous bone fixation is specially useful (with or without plates) in multilevel corpectomy.

Post operatively, a hard cervical collar is advised for six weeks.

Posterior approach may be indicated in canal stenosis, either congenital or degenerative with hard disc protrusions or hypertrophy of the ligamentum flavum or multi segmental OPLL.

C3 to C7 posterior laminectomy is recommended despite the level of involvement and gives adequate decompression. Additional foraminotomy (removal of the posterior wall of the intervertebral foramen) is helpful in myeloradiculopathy.

Occasionally a soft lateral disc protrusion can be removed through hemi or a partial laminectomy or through an interpedicular approach.

The complications of an extensive laminectomy are, late development of spinal deformity and peridural fibrosis. These can possibly be avoided by expansive laminoplasty. It is performed by completely incising the laminae on one side and partially on the opposite side. Elevation with tilting of the lamina upwards on the incised side allows enlargement of the canal.

Whatever the surgical approach used, improvement can be expected if symptoms have been present for less than two years. Results of treatment are also influenced by the degree of cord compression, changes in signal intensity of the cord on MRI and number of levels involved.

OPLL-Post corpectomy with titanium cage fixation AP & LAT

C-5/C-6 Listhesis PRE & POST OP

Radiculopathy improves dramatically.

In myelopathy, the motor functions improve faster and better as compared to sensory symptoms.