Lumbar Disc Herniation (Lower Back Disc)
Summary/Definition
The intervertebral disc is composed of a jelly-like nucleus pulposus surrounded by a fibrous ring, and it plays a role in shock absorption and maintaining the flexibility of the spine. The spine is divided into four parts: cervical, thoracic, lumbar, and sacral. The thoracic spine’s movement is restricted by the ribs, and the sacral spine is fused into one bone, so it does not have intervertebral discs. As a result, disc herniation mainly occurs in the more mobile cervical (neck) and lumbar (lower back) regions. Lumbar disc herniation, commonly referred to as a ‘disc,’ is a condition where the nucleus pulposus, the content of the intervertebral disc located between the vertebrae, protrudes through the fibrous ring of the disc, compressing the nerves and causing various neurological symptoms.
Lumbar disc herniation (lower back disc) refers to a condition where the nucleus pulposus herniates from the intervertebral disc in the lumbar spine (lower back) and compresses the adjacent nerves. The lumbar spine consists of five bones located at the lower part of the spine. In most cases, lumbar disc herniation causes lower back pain and radiating pain down the leg. It commonly occurs when excessive pressure or trauma is applied to the spine, such as when suddenly lifting heavy objects, twisting the lower back, maintaining a slouched posture for extended periods, or experiencing impact from a car accident, or due to degenerative changes. It frequently occurs between the 4th and 5th lumbar vertebrae or between the 5th lumbar and 1st sacral vertebrae.
Symptoms
The main symptoms of lumbar disc herniation include lower back pain and radiating pain in the lower limbs. Typically, lower back pain appears first, followed by radiating pain in the lower limbs. The radiating pain occurs when the herniated disc compresses a specific nerve, causing sharp and burning pain along the distribution area of that nerve. If nerve root compression persists, muscle weakness and sensory abnormalities may develop, and if there are urinary or bowel dysfunctions, urgent conditions like Cauda Equina syndrome must be differentiated.
The most characteristic symptom is ‘sciatica.’ The sciatic nerve is a thick nerve formed by the lumbar and sacral nerves, running down the back of the buttocks and thighs, and is responsible for the sensation and movement of the legs. When the herniated disc compresses one or more nerves that make up the sciatic nerve, pain occurs in the lower limbs. Sciatica can range from sharp, electric shock-like pain to burning or throbbing sensations, feelings of tightness or pulling, or even tingling or numbness. The pain radiates from the buttocks down to the legs and sometimes extends to the feet. It usually affects one leg but can also affect both legs depending on the location and extent of the herniated disc. Additionally, as nerve compression progresses, the motor nerves in the lower limbs may become paralyzed, leading to muscle weakness, muscle atrophy, or even paralysis.
The main symptoms of lumbar disc herniation are as follows:
- A tingling or pulling sensation radiating down the leg
- Pain in the lower back or buttock area
- Leg muscle weakness, making the leg feel heavy and lacking strength
- Sensory differences between the two legs
The symptoms vary depending on the location of the herniated disc, corresponding to the area governed by each spinal nerve:
- L4-L5 Lumbar Disc Herniation: There may be numbness and a tingling or pulling pain from the buttock down the back of the leg (slightly to the outside) extending to the top of the foot and the big toe. In severe cases, the muscles that lift the big toe or the ankle may become paralyzed, causing a person to drag their toes while walking.
- L5-S1 Lumbar Disc Herniation: Numbness and a tingling or pulling pain may occur from the buttock down the center of the back of the leg to the calf, extending to the sole of the foot and the little toe. In severe cases, the muscles that flex the toes and ankle toward the sole of the foot may become paralyzed, making it difficult to walk on the heels.
Diagnostics
Herniated disc (disc herniation) can usually be diagnosed through a detailed medical history and physical examination. It is important to check for abnormalities in deep tendon reflexes, sensation, and muscle strength through neurological tests. While the muscle strength test, sensory test, and reflex test for lumbar disc herniation are similar to those for cervical disc herniation, additional physical examinations can further clarify the diagnosis.
*Physical Examination
1. Posture and Spinal Appearance Examination
Patients with lumbar disc herniation often unconsciously lean their bodies to reduce pain. This is a response where the upper body is tilted in a direction that lessens the nerve compression caused by the herniated disc. Additionally, when walking, due to pain or lower limb muscle weakness, patients may limp, or if they have foot drop, they might excessively bend the hip and knee joints to avoid dragging the foot. If the hip abductor muscles weaken, the pelvis may tilt towards the affected side when lifting the leg on the opposite side of the affected nerve root or lower limb during walking.
2. Range of Motion Test
This test evaluates the degree to which the patient can bend or rotate the lower back. In cases of lumbar disc herniation, the range of motion in the joints is often limited during movements such as bending forward, extending the back, or bending sideways. When the body is tilted toward the side affected by the herniated disc, the pain intensifies, and localized tenderness and muscle stiffness may occur.
3. Straight Leg Raise Test
The straight leg raise test is a fundamental examination for diagnosing lumbar disc herniation. The patient lies flat on their back with the knee extended, and the examiner slowly lifts the heel. If radiating pain occurs between 30 and 70 degrees, the test is considered positive. As the leg is lifted beyond 30 degrees, the nerve running around the hip joint is stretched, and beyond 70 degrees, no further stretching occurs. In normal conditions, this level of stimulation does not stress the nerve, but if the nerve is already under tension due to the herniated disc, pain arises. The straight leg raise test typically yields a positive result in issues involving the L4, L5, and S1 nerve roots. The L2 and L3 nerve roots, which travel through the femoral nerve, do not produce a positive response in this test. If the upper lumbar nerve roots are affected, a femoral nerve stretch test is performed. In this test, the patient lies face down, and the knee is flexed while the hip is extended; if pain occurs in the front of the thigh, the test is considered positive.
*Imaging Tests: After taking the patient’s medical history and conducting a physical examination, the following additional tests may be performed as needed.
1. X-ray Examination
An X-ray of the lumbar spine is used to detect spinal fractures, osteoarthritis, spondylolisthesis, tumors, infections, and congenital abnormalities. While a herniated disc itself cannot be diagnosed with X-rays, associated bone abnormalities can be relatively easily identified.
2. Computed Tomography (CT)
Although rarely used today, CT scans, often combined with myelography (spinal canal contrast imaging), can be employed when MRI is not available to identify disc herniation or spinal stenosis.
3. Magnetic Resonance Imaging (MRI)
MRI is the most effective and definitive test for diagnosing disc herniation. It allows observation of the location, size, shape, and degree of nerve compression caused by the herniated disc, as well as the differentiation of other lesions such as tumors, vascular abnormalities, and fractures.
4. Myelogram
This test involves injecting a contrast agent into the cerebrospinal fluid and taking X-ray images to identify spinal cord compression caused by disc herniation, bone spurs, or tumors. Due to its invasive nature, it has largely been replaced by MRI in recent years.
5. Electromyography (EMG) / Electroneurography (ENG)
These tests analyze the electrical activity of muscles, peripheral nerves, and nerve roots to objectively assess nerve compression or damage. They can be used as supplementary tests when radiological examinations are insufficient.
Treatment and course of the disease
The treatment of a herniated disc primarily involves non-surgical, conservative methods during the first four weeks if there is no accompanying muscle weakness or sensory abnormalities. However, if there is no improvement or if the condition worsens after 4 to 6 weeks, surgical treatment is recommended. If there is severe muscle weakness, significant sensory abnormalities, or if imaging tests show severe nerve compression, surgical treatment may be considered from the outset. Additionally, surgical treatment is prioritized if there is neurological damage leading to urinary or bowel dysfunction or signs of cervical myelopathy.
*Non-surgical, conservative treatment:
1. Rest and Relaxation
In cases of acute herniated disc, it is important to reduce activity and take bed rest for a few days during the initial onset of symptoms. Absolute rest should be maintained, particularly for the first 2-3 days. During this time, it is recommended to lie down with a pillow placed under the knees to keep the hip and knee joints in a flexed position. However, prolonged bed rest without any activity can cause the pain to persist or worsen, so the bed rest period should not exceed 2-3 days.
2. Physical Therapy
The goal of physical therapy is to restore the muscle strength, flexibility, and function that may have been reduced due to pain and spasms. It is important to avoid positions that increase intradiscal pressure or tension on the nerve sheath. Exercise therapy should include stretching and strengthening of the muscles surrounding the spine, as well as exercises to strengthen the neck, glutes, hamstrings, and abdominal muscles, which are crucial for stabilizing the spine. Cervical traction can be beneficial for some patients, but excessive traction may cause pain, so it should be used with caution. Additionally, adjunctive therapies using medical devices, such as ultrasound, radiofrequency therapy, hot packs, and cold packs, can be effective for short-term symptom relief.
3. Medication Therapy
Anti-inflammatory drugs are effective for managing pain associated with a herniated disc. Non-steroidal anti-inflammatory drugs are commonly used, but caution is necessary due to the potential for long-term use to cause gastrointestinal mucosal damage, bleeding, and effects on liver and kidney function. In cases of severe pain during the acute phase, short-term use of opioid analgesics may be considered, but they should not be used for more than 2-3 days. Additionally, short-term oral corticosteroids can be used to reduce chemically induced inflammatory pain, and muscle relaxants may be effective for relieving acute muscle spasms over a short period.
4. Injection Therapy (Selective Cervical Epidural Steroid Injection)
If symptoms do not improve with other non-surgical treatments, selective cervical epidural steroid injections may be considered. This method involves using imaging guidance to accurately identify the affected nerve root, followed by the injection of steroids and local anesthetics into the affected area. According to a 2002 study, this technique is highly effective, helping to alleviate inflammation of the nerve root, stabilize the nerve cell membrane, and block pain mediators, leading to symptom improvement and maintenance in approximately 77% of patients, thereby potentially avoiding the need for surgery.
*Surgical Treatment:
The most commonly used standard surgical method for treating lumbar herniated discs is open discectomy. However, with the growing interest in minimally invasive surgery, techniques such as microdiscectomy using tubular retractors and endoscopic discectomy are increasingly being performed. Depending on the location of the herniated disc, particularly if it is situated in the foraminal or extraforaminal region, removal of the facet joint may be necessary to access the disc, and in some cases, spinal fusion may be required. Since the intervertebral disc is a non-regenerative tissue, it is replaced by fibrous scar tissue after resection.
Prevention and Management
Maintaining proper posture is crucial in preventing lumbar herniated discs. It is important to adopt postures that help maintain the appropriate lumbar lordosis as follows: When lifting objects, hold them close to your body. When sitting, ensure that your hips are positioned against the back of the chair, with the hip joint maintained at approximately 95°. While standing, place one foot on a low box or similar object to help maintain lumbar lordosis.
Exercises that help maintain lumbar lordosis include the following:
- Swimming: Strengthens muscles while reducing strain on the lower back.
- Golf: When done with proper posture, it helps maintain lumbar lordosis.
- Horseback Riding: Strengthens the spine and core muscles.
On the other hand, activities that require frequent bending of the back, such as gardening, racquetball, and tennis, are not recommended. However, lumbar flexion exercises are encouraged. These exercises help widen the space between the intervertebral discs at the back, expand the intervertebral foramen and posterior facet joints, strengthen the abdominal and gluteal muscles, and make the lumbosacral joints more flexible, thereby helping to prevent herniated discs. Representative exercises include:
- Williams Exercise: Lie on the floor with your knees bent and slightly curl your upper body to strengthen the abdominal muscles.
- Knee-to-Chest Exercise: Bend your knees and bring them to your chest to stretch the hip extensor muscles.
- McKenzie Exercise: Kneel on the floor and move your lower back up and down.
- Sit-Ups: Strengthen the abdominal muscles.
- Walking Exercise: Walking is preferable to running.
However, for patients who already have a herniated disc, improper exercise can be harmful. Therefore, it is important to consult with a doctor and receive a prescribed exercise regimen tailored to your specific condition to ensure safe practice.
