Lumbar Disc Protrusion - Cause, Symptoms, Diagnosis, and Treatment

Introduction:

Lower back pain is a common complaint in the majority of the population experienced by everyone at least once in their lifetime. Lumbar disc protrusion or herniation is the most common cause of back pain and leg pain. The common cause of disc protrusion is intervertebral degeneration.

What Is Lumbar Disc Protrusion?

Lumbar disc protrusion is the bulging or protrusion of the soft cushion between the vertebral bones called intervertebral discs, through the weak areas of the tougher outer covering of the spinal cord. It is also known as herniated, bulged, slipped, ruptured, or prolapsed disc. The most common site of lumbar disc herniation occurs at L4-L5 or L5-S1.

Anatomy of the Spinal Cord

The vertebral column, or backbone, is made up of 33 vertebrae that are separated by spongy disks. The spine is divided into 4 areas:

• Cervical spine: There are 7 vertebrae in the neck.

• Thoracic spine: There are 12 vertebrae in the chest region.

• Lumbar spine: There are 5 vertebrae in the lower back.

• Sacral spine: There are 5 vertebrae below the waist, including the 4 vertebrae forming the tailbone called the coccyx.

The lumbar part of the spinal cord has five vertebrae and five intervertebral discs giving an inward curve to the lumbar. There is a foramen within the vertebrae through which the spinal nerves passes. The intervertebral discs are flexible, flat, and round, and shock absorbers during movements like walking and running. They consist of two components:

• Annulus fibrosis: This is the hard outer layer of the disc which is flexible.

• Nucleus pulposus: This part is soft and present in the center of the docs having a jelly-like structure.

What Is the Cause of Lumbar Disc Protrusion?

Disc herniation is due to degeneration of the vertebral disc. The process of degeneration starts with aging when the fibro chondrocytes lose the ability to divide and grow and this causes a reduction in proteoglycans. This leads to dehydration and loss of strength. The disc collapses and increases the strain on annulus fibrosus. Tears and fissures develop which leads to herniation of the nucleus pulposus. When the spinal cord is under continued stress, the patient starts to experience the symptoms, making it a chronic condition.

What Are the Risk Factors of Lumbar Disc Protrusion?

Herniations occur when a patient has certain risk factors for the condition.

• Gender: Males belonging to age groups between 20 and 50 are more prone to be affected by herniation.

• Obesity: Individuals who are overweight can have higher chances of the herniated disc due to overload on the spine.

• Decreased Physical Activity: Lack of exercise and physical inactivity can increase the chances of herniation.

• Repeated Driving: Driving for long hours and more frequently can put more stress on the lumbar spine due to the car engine vibrations.

• Lifting With Back Muscles: People who lift weights using back muscles instead of legs will lead to herniation of the lumbar spine. Lifting using the right muscles and technique will prevent the problem.

• Smoking Habit: Smoking will cause less oxygen supply to the tissues of the vertebral disc which can fasten disc degeneration.

What Are the Signs and Symptoms of the Lumbar Disc Protrusion?

• Lower back pain.

• Radicular pain.

• Loss of sensation leading to numbness along the nerve distribution from the lumbosacral spine.

• Weakness along the nerve distribution of the lumbosacral spine.

• Increase in pain when coughing, sneezing, or straining.

• Increase in pain while sitting, which put pressure on the nerve root.

• Restricted flexion of the trunk.

• Back muscle spasms.

• Changes in bladder and bowel movements.

• Decreased knee or ankle reflexes.

How Is Lumbar Disc Protrusion Diagnosed?

• Straight Leg Raise (SLR) Test: It is used to test lumbar herniation in young patients. The patient is asked to lie down and lift their leg if the patient feels pain down the leg and below the knee, it confirms the diagnosis of lumbar disc herniation.

• Blood Tests: Complete blood count will determine the infection and inflammation by measuring the inflammatory markers which are erythrocyte sedimentation rate(ESR) and C- reactive protein levels in the blood.

• X-Rays: The first choice of the imaging device is lumbar X-rays. They are taken when the patient complains of low back pain taken in three views which are anteroposterior(AP), lateral and oblique views. Through this, The degenerative and damaged disc can be evaluated along with the overall alignment of the spine and any associated fractures. Special views like lateral flexion and extension can assess the instability of the spine. The radiographic findings such as narrowing of intervertebral discs, compensatory scoliosis(lateral curvature of the spine), and traction osteophytes( bony structure protruding from the vertebral end plate).

• Computed Tomography (CT): It is a more sensitive imaging tool to evaluate the spine. It is beneficial in assessing calcified protruded discs, bone loss, or any bone abnormalities. But it can not give much information about the nerve roots, so it has limited use in the diagnosis of radiculopathy(pinching of nerves root)

• Magnetic Resonance Imaging (MRI): This imaging technique is the gold standard for confirmation of lumbar disc protrusion. Since it can visualize soft tissue with 97 percent accuracy, it is most often the most sensitive tool to examine a herniated disc. It is used at an early stage of the disease when the patient presents with the complaint of back pain, numbness, and neurological motor deficits. A type of MRI called diffusion tensor imaging can examine nerve root abnormalities.

What Is the Treatment for Lumbar Disc Protrusion?

The symptoms of lumbar disc protrusion are present for a short time and will resolve on its own in 6 to 8 weeks when the condition is mild without any alarming symptoms.

• Conservative Management:

  • It is the first step in the treatment of lumbar disc protrusion when The symptoms are acute.

  • Painkillers along with rest, some form of physical therapy, and exercises are advised.

  • Non-steroidal anti-inflammatory drugs are given first, if unresponsive, opioid analgesics are recommended.

  • If the patient continues to experience symptoms beyond 6 weeks, interlaminar or transforaminal epidural steroid injections are considered to relieve pain, given for a short period of 2 to 4 weeks.

• Surgical Treatment:

  • Laminotomy and Discectomy: It is a conventional surgical procedure, which means to open the lamina at the back of the spinal bone (laminotomy) and remove the damaged disc (discectomy).

  • Microdiscectomy: It is an improved technique of laminotomy and discectomy with smaller incisions. It is a minimally invasive technique.

  • Endoscopic Discectomy: It is the same procedure as laminotomy and discectomy performed with an even smaller incision using a specialized camera lens which helps the surgeon to view the spinal canal and disc contents.

What Is the Differential Diagnosis of Lumbar Disc Protrusion?

• Muscle spasms.

• Cauda equina syndrome.

• Osteophytes.

• Mechanical back pain.

• Spondylolisthesis.

• Epidural abscess or hematoma.

• Ankylosing spondylitis.

• Neurinoma.

• Degenerative spinal stenosis.

What Are the Complications of Lumbar Disc Protrusion?

Chronic back pain is the most common complication of lumbar disc herniation. In addition, improper treatment can lead to permanent irreversible nerve and lumbar disc damage resulting in neuropathic pain with severe radiculopathy. The complications post-treatment are:

• Post-Surgical Complications:

  • Aggravated functional inability.

  • Dural tear.

  • Nerve root damage.

  • Post-operative infection.

  • Recurrent disc protrusion.

  • Epidural fibrosis.

  • Injury to great vessels.

• Epidural Steroid Injection Complications:

  • Epidural abscess and hematoma.

  • Infection.

  • Dural puncture leading to positional headache.

  • Nerve injury.

  • Paralysis.

Conclusion

Lumbar disc protrusions are a temporary and short-lived condition that gets resolved within six to twelve weeks and required no interventional treatment. If symptoms persist beyond six weeks, the patient would require some kind of medical intervention. Patients without any nerve root involvement will improve in a short time. Conservative treatment will give relief after long-term therapy but surgery will give faster pain relief and restoration of function.