Pressure on the nerve roots as they leave the spine produce symptoms of nerve compression, and the nerve roots in the lumbar region of the spine are most liable to be pinched or compressed as a result of maximum movement of the vertebrae in this region. Lumbar nerve compression is commonly known as sciatica, which is the most frequent of all the pinched nerve conditions.
The lumbar parts of the spine bears the weight of the lower part of the body and is more prone to wear and tear due to a number of causes, such as improper bending and lifting with pressure on this area, apart from normal wear and tear associated with age. This causes early degeneration of the intervertebral discs in the lumbar area, which puts pressure on the nerves, resulting in lumbar radiculopathy.
The nerves that leave the lower lumbar spine join to form the sciatic nerve, the longest nerve in the body, which controls the muscles of the lower leg and provides sensation to it. Pressure on the nerve roots of the lumbar spine causes pain and numbness in the area supplied by the sciatic nerve and may lead to muscle weakness and loss of reflexes.
Symptoms of Lumbar Nerve Compression
- Shooting pain along the distribution of the sciatic nerve, running from the buttocks, thigh and legs and may radiate to the feet.
- Tingling or “pins and needles” sensation in the buttocks, leg and calf.
- Numbness or decreased sensation.
- Muscle weakness in the leg.
- Muscle spasm.
- Symptoms may aggravated while walking.
The most common symptoms related to a pinched nerve at different levels are :
- Nerve compression at L3, L4, and L5 results in symptoms of sciatica, caused by pressure on the sciatic nerve. Shooting pain may be felt at the lower back, radiating down to the buttocks, thigh and legs.
- Nerve compression at L5 causes muscle weakness of the foot and big toe since the L5 nerve controls the muscles involved in lifting the foot and big toe.
- Compression of the S1 nerve results in weakness of the muscle at the back of the calf, with difficulty in foot push off and numbness along the outer side of the foot. There may be low back pain, which continues down the buttocks, to the thigh and legs, to the outer side of the little toe.
Conditions Related to Nerve Compression in the Lumbar Region
Refer to the article on Sciatic Nerve Pain.
2. Herniated Intervertebral Disc
Repeated injury may weaken the outer layer of the intervertebral disc so that it breaks and the inner gelatinous layer protrudes out and produces herniation of the disc. Often a sudden movement may cause rupture of the outer layer with resulting herniated disc. If the nerve root gets compressed by the herniated disc, there may be pain, numbness, and weakness of the region supplied by the nerve.
3. Degenerated Intervertebral Discs
Due to age-related wear and tear of the lumbar vertebrae and the intervertebral discs, there is gradual and progressive degeneration of the discs, leading to compression of the nerve as it exits through the foramen, giving rise to symptoms of nerve compression.
4. Lumbar Stenosis
Narrowing of the spinal cord at the level of the lumbar vertebrae is called lumbar stenosis and this may occur due to various causes.
- Spondylosis. The most common cause of lumbar stenosis is degeneration of the spinal cord as a result of age, or osteoarthritis-related bone changes, and this is known as spondylosis.
- Spondylolisthesis. Either due to degeneration or trauma, one vertebra may slip over the other, causing misalignment and narrowing of the spinal canal, resulting in features of lumbar stenosis.
- Congenital. There may be a narrow spinal canal present as a congenital defect, which is a defect that is present since birth.
- Bone spurs. In late stages of spinal degeneration bone spurs form, which further narrow the spinal canal.
- Spinal tumors. Abnormal growths inside the spinal cord, within the meninges or membranes covering the spinal cord, or in the space between the spinal cord and vertebrae. Metastasis or spread of malignancy to the spinal cord from other parts of the body may occur too.
- Injury. Such as in car accidents or other type of trauma.
Diagnosis of Lumbar Nerve Compression
Diagnosis is based mainly on the history and physical examination but associated tests may need to be done and these include :
- Nerve conduction study or nerve conduction velocity test
- Magnetic resonance imaging or MRI
- Computed tomography or CT scan
Treatment of Lumbar Nerve Compression
Treatment will be guided by the cause of nerve compression, but may include :
- Bed rest with or without traction.
- Exercises to strengthen the muscles of the affected area.
- Avoiding activity that aggravates the condition.
- Wearing a support or brace.
- Medication to relieve pain, such as ibuprofen, or muscle relaxants. Corticosteroid injections into the affected area often help.
- Surgery will depend on the type of compression and if the symptoms are not relieved by conservative treatment.