Lumbar discal herniation is a condition in which the inner material of a disc in the lower back protrudes through the outer layer and compresses or irritates the nearby nerve roots or the spinal cord. It is a common cause of low back pain and unilateral leg pain, known as radiculopathy. In rare cases, a large disc herniation can lead to cauda equina syndrome, which requires emergent diagnosis and treatment.
The exact cause of lumbar discal herniation is not always clear, but some factors that may contribute to it are:
– Aging. As people get older, the discs lose water and elasticity, making them more prone to tearing or rupturing.
– Injury. A sudden trauma, such as a fall, a car accident, or a sports injury, can cause a disc to herniate.
– Repetitive stress. Activities that involve frequent or prolonged bending, twisting, or lifting of the lower back can put pressure on the discs and cause them to wear out over time.
– Genetics. Some people may have a predisposition to disc herniation due to inherited traits or conditions that affect the spine.
The symptoms of lumbar discal herniation depend on the location and severity of the herniation, as well as the nerve or spinal cord involvement. Some common symptoms are:
– Low back pain. This may be sharp, dull, or burning, and may radiate to the buttock, thigh, or leg.
– Leg pain. This may be felt along the path of the affected nerve, and may be accompanied by numbness, tingling, or weakness.
– Foot drop. This is a condition in which the patient cannot lift the front part of the foot due to weakness of the muscles innervated by the peroneal nerve.
– Spinal cord compression. This may cause symptoms such as difficulty walking, loss of balance, loss of bladder or bowel control, or sexual dysfunction.
The diagnosis of lumbar discal herniation is made clinically based on the history, physical examination, and neurological tests. The diagnosis is confirmed with imaging studies of the lumbar spine, such as:
– MRI. This can provide detailed images of the spine and the soft tissues, and can show the extent and location of the herniation, as well as the nerve or spinal cord compression, inflammation, or edema.
– CT scan. This can provide cross-sectional images of the spine and the discs, and can show the degree of disc degeneration, calcification, or fragmentation.
– X-rays. These can show the alignment of the vertebrae and the presence of any infection, tumor, fracture, or arthritis. If a discal herniation is suspected, an advanced imaging like MRI or CT is preferred.
– Myelogram. This involves injecting a dye into the spinal fluid and then taking a CT scan. This can show the pressure on the spinal cord or the nerve roots due to the herniation or other conditions. Nowadays this method is rarely used.
Imaging studies results can distinguish discal bulging from herniation. The difference between a herniated disc and a bulging or protrusion disc is that a herniated disc is when the inner, gel-like material of the disc leaks out through a tear in the outer layer, while a bulging disc is when the outer layer of the disc bulges outwards, but the inner material does not leak out. A disc protrusion is a more advanced stage than a bulging disc. Not only does the outer wall bulge outward, but the inner gel has migrated to the very edge of the annulus fibrosus. It can be thought of as a middle stage between a bulging disc and a herniated disc. Both conditions can cause pain and other symptoms if they compress or irritate the nearby nerve roots or the spinal cord.
Lumbar discal herniation can be confused with other conditions that cause similar symptoms, such as:
– Lumbar spinal stenosis. This is a narrowing of the spinal canal or the nerve root openings in the lower back, causing compression of the nerve roots or the spinal cord. It is usually due to degenerative changes of the spine, such as bone spurs, thickened ligaments, or bulging discs.
– Lumbar spondylosis. This is a degenerative condition that affects the joints and bones of the lower back, causing pain and stiffness in the lower back and legs.
– Lumbar radiculopathy. This is a condition that occurs when a nerve root in the lower back is irritated or compressed by a bone spur, a tumor, an infection, or a spinal stenosis, causing pain, numbness, or weakness in the leg.
– Lumbar strain or sprain. This is a common injury that affects the muscles or ligaments of the lower back, causing pain and stiffness in the lower back and buttocks.
– Sciatica. This is a term that refers to pain that radiates along the sciatic nerve, which runs from the lower back, through the buttock, and down the back of the leg. It can be caused by various conditions, such as lumbar disc herniation, spinal stenosis, piriformis syndrome, or sacroiliac joint dysfunction.
The treatment of lumbar discal herniation depends on the severity of the symptoms, the degree of nerve or spinal cord compression, and the response to conservative measures. The main goals of treatment are to relieve pain, restore function, and prevent further damage. Some common treatment options are:
– Conservative treatment. This includes modifying activities, avoiding movements that worsen pain, taking medications (nonsteroidal anti-inflammatory drugs, analgetics, corticosteroids, antiedema, opioids), applying heat or ice, and doing physical therapy or exercises to strengthen the lower back muscles and improve posture and flexibility.
– Epidural steroid injection. This involves injecting a corticosteroid and a local anesthetic into the epidural space around the spinal cord or the nerve root. This can reduce inflammation and pain, and may improve nerve function.
– Surgery. This is considered when conservative treatment fails, or when there is severe nerve or spinal cord compression that causes neurological deficits or threatens the spinal cord function. The patient must be referred to a neurosurgeon or orthopedic surgeon if there is neurological deficit and insufficient response to conservative treatment.
Lumbar discal herniation is a common condition that affects the discs in the lower back. It can cause pain, stiffness, and neurological symptoms in the lower back, buttock, thigh, or leg. It can be diagnosed by a clinical exam, a medical history, and imaging studies. It can be treated by conservative measures, epidural steroid injection, or surgery, depending on the severity and the response to treatment. As medical students, you should be familiar with the anatomy, pathophysiology, diagnosis, and treatment of lumbar discal herniation, as it is a frequent cause of low back pain and disability in the general population. You should also be able to educate your patients about the prevention, management, and prognosis of this condition, and provide them with the best possible care.