Foraminal stenosis is the narrowing of one or more vertebral foramen. Vertebral foramen refers to the opening between the anterior segment and the posterior segment of the vertebral column, allowing nerve roots to pass through it. Vertebral foramen is located on the left and right side of the spine. Vertebral foramen is placed from the cervical spine up to the lumbar spine.
Definition of Foraminal Stenosis
Foraminal stenosis involves the reduction in size of the vertebral foramen that allows the nerve roots to pass through it. Once the space has decreased because of stenosis, the nerve roots become compressed.
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Types of Foraminal Stenosis
Foraminal Stenosis has varied types depending on the location, severity and area of narrowing.
Types according to the area of narrowing:
Bilateral Foraminal stenosis
Bilateral foraminal stenosis involves the narrowing of the foramina on both sides of the spine. Foramen is located on both sides of the spine and the narrowing of both sides causes bilateral foraminal stenosis.
Unilateral Foraminal stensois
Unilateral stenosis only involves the stenosis on the left of the spine
Far Lateral stenosis
This involves narrowing where the nerve root has exited the foramen.
Types according to Location
Cervical stenosis is the most common form of foraminal stenosis. The affectation of the nerve roots in the area commonly affect the neck, shoulders, head, arms, hands and upper back.
Thoracic stenosis is an uncommon form because this area is usually protected from degenerative diseases. When this area is affected, common locations include the ribs, arms, shoulders and internal organs.
Lumbar stenosis is also a common form of foraminal stenosis affecting the lower extremities, buttocks, and lower back.
This involves the narrowing of the foramen at different levels in the spine. This is a more severe type because it can affect one or more areas in the body.
Types according to severity
Mild foraminal stenosis primarily results from natural aging. Some cases are asymptomatic and may not be detected.
Moderate foraminal stenosis or neural foraminal stenosis is the gradual narrowing of the passage ways of nerve roots. This also involves more evident symptoms such as pain and alterations in senses in the extremities or any area of affectation. Neural foraminal stenosis involves the significant compression of nerves as compared with mild stenosis. This is usually caused by disc degeneration.
Severe foraminal stenosis is a degenerative condition that causes severe pain in the back or neck. This results from wear and tear that the spine experiences and is usually exacerbated by injury.
Causes of Foraminal Stenosis
Several factors cause clogging or narrowing of the vertebral foramen. These include:
This is the most common cause of foraminal stenosis as a result of natural aging. Disc degeneration usually develops after disc herniation or the bulging of the disc outside its cavity.
The occurrence of this degenerative condition as a result of rheumatoid arthritis causes the foramen to narrow. This is caused by the thickening of the joint tissue, calcification of the spine, bone spurs, and inflammation in the area.
This is one of the most common causes of cervical foraminal stenosis. This results from the degeneration of the spine as a result of its weight-bearing function. Osteoarthritis involves damage to the cartilage on the spine’s joints that may cause bone spurs that may impede the passage of nerve roots.
Congenital spinal stenosis
Narrowing of the vertebral column that appears during the fetal development may also cause foraminal stenosis.
Scoliosis is a condition wherein there is lateral curvature of the spine. This may affect one side of the vertebrae and lead to unilateral foraminal stenosis.
Increasing age also plays a role in the development of foraminal stenosis. As people age, the spinal integrity becomes affected, leading to narrowing of the foramen.
Repetitive tension on the spine as a result of high impact activities can also lead to bone changes such as calcifications and bone growths that obstruct the nerve passage.
Symptoms of Foraminal Stenosis
Symptoms of foraminal stenosis occur because of compression of the nerve roots. Nerve roots innervate specific areas of the body and these areas may be affected. Some of these include:
- Pain on the area affected such as back pain, leg pain or shoulder pain
- Diminished reflexes
- Paresthesia or the feeling of tingling and pins and needles in the affected area
- Loss of function as a result of an untreated condition
Pain can also be characterized as radicular, which means that there is the presence of pain along the dermatomes and the affected nerve root areas. Pain can be characterized as sharp and aching.
Diagnosis of Foraminal Stenosis
Diagnosis of foraminal stenosis is done using the following procedures:
Physicians often perform physical examination, focusing on the assessment of sensations such as touch, pain and temperature. The reflexes are also checked and the examiner will also assess for muscle strength.
X-rays, CT scans, and MRI scans be done to ascertain the diagnosis. These tests provide a view of the spine and the extent of the compression and narrowing. These also determine the extent of treatments needed, from conservative anti-inflammatory medications to surgery.
Treatment of Foraminal Stenosis
The treatment for foraminal stenosis depends on the extent of symptoms and the narrowing. Several methods can be employed, including:
This is a surgical procedure that employs the creation of an opening on the blocked foramen, used for more severe cases of narrowing.
Selective Nerve Root Block
This involves temporary pain relief by injecting anesthetics in the spine in the affected area to relieve pain. This treatment is also called selective transforaminal epidural injection.
To improve the mobility of the patient and reduce symptoms, physical therapy may be employed as a conservative management for this condition.
Rest is an important treatment method to prevent further damage and nerve compression. In cases of severe stenosis that cause severe pain, immobilization may sometimes be required.
Medications that relieve inflammation are also given to reduce the inflammatory process in the area and reduce nerve compression. Anti-inflammatory medications can be in the form of non-steroidal anti-inflammatory drugs or corticosteroids.