Cervical and Lumbar disc prolapse

Disc Prolapse

The Intervertebral Disc:

The intervertebral discs make up one fourth of the spinal column's length. There are no discs between the Atlas (C1), Axis (C2), and Coccyx.

The intervertebral discs are fibrocartilaginous cushions serving as the spine's shock absorbing system, which protect the vertebrae, brain, and other structures (i.e. nerves). The intervertebral disc is formed of 3 structures as follow:

1.The Annulus Fibrosus:

The annulus fibrosus is a strong radial tire like structure made up of concentric sheets of collagen fibers. The annulus encloses the nucleus pulposus. The posterior portion of the annulus is thinner than the rest of the annulus , this leads to more tears posteriorly.  

2.The Nucleus Pulposus:

It consists of a 3 dimentional network of collagen fibres , enmeshed in a mucoprotein gel . Although both the annulus fibrosus and nucleus pulposus are composed of water, collagen, and proteoglycans (PGs), the amount of fluid (water and PGs) is greatest in the nucleus pulposus The nucleus pulposus contains a hydrated gel–like matter that resists compression.

3.End Plates:

Discs are not vascular and therefore depend on the end plates to diffuse needed nutrients. The cartilaginous layers of the end plates anchor the discs in place. It iIii

Disc Prolapse (Herniation of Nucleus Pulposus):

Degress of herniation

Disc Degeneration: drying and thinning of the disc as a result of accelerated wear and tear .

Disc Protrusion: Commonly called a disc bulge, a disc protrusion occurs with the spinal disc and the associated ligaments remain in tact, but form an outpouching that can press against the nerves.

Disc Extrusion: A disc extrusion occurs when the outer part of the spinal disc ruptures, allowing the inner, gelatinous part of the disc to squeeze out. Disc extrusions can occur with the ligaments in tact, or damaged.   

Disc Sequestration: A disc sequestration occurs when the center, gelatinous portion of the disc is not only squeezed out, but also separated from the main part of the disc and it is the end of the extrusion phase.

Mechanism of Pain of Disc Prolapse:

1. Stretching the fibers of an abnormal annulus .

2. Extravasation of extradurally irritating substances such as lactic acid  .

3. Pressure on nerves posteriorly caused by bulging of the annulus .

This will cause inflammation to the nerve roots which called sciatica , in lower limb ,and branchialgia , in upper limb  .

Diagnosis:

1. History

2. Clinical examination

3. E.M.G

4. M.R.I

Management:

1. Selected nerve root steroids injections.

2.Application of pulsed radiofrequency on D.R.G ( see radiofrequency chapter) .

3. Minimally invasive discectomy (see next chapter of minimally invasive diecectomy).