Home » Condition » Migrated Disc Prolapse
Spinal discs are rubbery pads between the vertebrae, the specialized bones that make up the spinal column. They are often called intervertebral discs. Each disc is a flat and circular capsule that have tough outer membrane (annulus fibrosus), and an elastic, gel like core (nucleus pulposus).
The discs are firmly held between the vertebrae by the ligaments. These discs are what allow optimal range of motion of the spine without damaging the spinal cord and nerves that run through the centre of the spinal canal.
In some people, due to damage to the spinal discs, they may become herniated. A herniation is when the outer fibrous layer of the disc ruptures and soft gel like core is extruded out of this rupture. A free fragment, also known as a “sequestered disc” is one type of herniated disc in which a piece breaks off from the main structure. This detached fragment can move up or down and cause repercussions at a different portion of the spine than the level of the actual herniation. The term “migrated disc fragment” may be used to refer to this free fragment of a herniated disc that has moved to a different location than its original site of formation.
Herniated disc fragments are known to migrate in various directions within the spinal canal.
Even though the exact cause and process of this phenomenon is not known, however some conditions can preclude you to developing migrating herniation. Typically, the spinal cord is covered my many protective membranes that protect it from damage. One of these membranes is called the “dura”. These membranes do not leave room for any foreign substance to migrate along them. Sometimes, chronic inflammation and thinning of the disc can end up causing a “dural defect” which the disc fragment may migrate into.
There can be other reasons for dural changes and defects that allow for this migration. This includes adhesions between the annulus fibrosus and the dura mater, genetic predisposition for narrowing of the spinal canal with less epidural space, thinness of the dura either from birth or as a result of surgery.
With a migrated disc prolapse, the symptoms generally result from contact between the free fragment and spinal nerve root. This can take place where the breaking off from the main disc occurs, or at another level to which the fragment migrates.
The symptoms caused by the disc herniation and migrated fragment result in radiculopathy symptoms, which is nothing but symptoms caused by a pinched nerve. The location of the free fragment determines the nature of the symptoms. If the fragment reaches your neck, you may experience symptoms in one arm. If the fragment migrates to your low back, you may experience symptoms in one leg.
Symptoms can include other nerve-related sensations such as pins and needles, burning or electrical shock, weakness and numbness as well.
Migrated disc prolapse can be diagnosed by your doctor by reviewing symptoms and spinal imaging results like MRI, CT and X-rays. Additional tests may be ordered when required.
Physical examination: The doctor may ask about the onset of pain, occurrence of any injury, any abnormal sensations, etc. The degree of motion, site of pain and evaluation of nerve and muscle using specific movements are also determined
Diagnostic imaging: Radiological investigations such as X-rays, CT scans and MRIs may be ordered to reveal any significant disc prolapses. An MRI scan is the most accurate test. Other investigations such as CT myelogram, and a nerve sheath injection with local anaesthetic may be recommended.
Specific correlations between physical examination and imaging studies can help determine the severity of the condition and help your doctor to make a suitable treatment plan.
Generally, conservative non-surgical care, is very successful in the treatment of migrated disc prolapse. These treatments consists of medications like pain killers and steroids and physical therapy, like stretching and strengthening exercises. In almost 75% of cases, spinal imaging studies show decreases in the free fragment sizes and sometimes complete resorption of free fragments may be noted without surgical intervention.
Resorption occurs when the body’s tissues that come into contact with the free fragments secrete substances that chemically break down the disc pieces. The broken-down disc material is, over time, re-absorbed by the body. However, although this is a safe route, it takes much longer for the problem to resolve and for pain relief.
Standard surgery for a simple herniated disc may not work for your sequestered disc fragment. Sometimes locating the free fragment or fragments can be challenging for your surgeon. In most cases, surgical treatment produced favourable outcomes.