Lumbar disc herniation
Lumbar disc herniation
ANATOMY OF THE SPINE
The human spine is formed by individual vertebrae and connective tissue discs in between. The vertebrae form the spinal canal. There are seven cervical, twelve thoracic, and five lumbar vertebrae. The intervertebral discs are the link between the individual vertebral bodies.
Normal anatomy of the spine. Longitudinal section and cross sections through the cervical, thoracic and lumbar spine.
The little joints that link the vertebrae together are known as facet joints. They help to stabilize the spine and, together with the intervertebral discs, allow a certain degree of mobility of the spinal cord. The spinal canal should be wide enough to allow nerve roots to float freely in cerebrospinal fluid.
The front border of the spinal canal is built by the vertebral bodies and intervertebral discs, the side by the intervertebral joints (facets) and back by the ligamentum flavum (yellow band) and vertebral arches. Discs consist of an outer fibrous ring (annulus fibrosus), which surrounds an inner gel-like center (nucleus pulposus).
The spinal cord and nerve roots lie within the spinal canal. The spinal cord extends downwards approx. to the 1st lumbar vertebra. Below, only nerve roots are present in the spinal canal. At the level of the intervertebral disc the nerve roots pass through the neural root foramina to exit the spinal canal. The spinal cord and nerve roots conduct electric-like signals from the skin and joints to the brain, and process of movement is initiated from the brain to the muscles.
Disc herniation is a disease of the intervertebral discs - the connecting element between the individual vertebral bodies. The intervertebral disc consists of a coarse hard shell (fibrous ring) and a soft cloth inside. Together with small intervertebral joints and other connective tissue connections, the intervertebral discs provide the mobility of the spine and serve as shock absorbers to soften the impact of body movements.
Lumbar disc herniation
A MRI image of a lumbar disc herniation
When the hard shell of the disc (the fibrous ring) breaks, the soft interior comes out of it and enters the spinal canal or the nerve root canals. At this time, any incoming material in the intervertebral disc can press the nerve roots or the spinal cord.
In most cases, the exact cause of disc herniation cannot be determined. Disc herniation is most often the result of aging. Factors increasing the risk of disc herniation are: 1) injury, 2) occupations requiring lifting, pushing and twisting and 3) hereditary.
Lumbar disc herniation (ICD M51.1) is a disease of the intervertebral discs in the lumbar region. It is most common between the vertebral bodies L4, L5, and S1. Here we will explain how the lumbar disc herniation is formed, the most common symptoms, and how the lumbar disc herniation is diagnosed and treated. Making an accurate diagnosis and choosing the proper treatment are the essential goals in patients with lumbar disc herniation. Interestingly, 80% of lumbar disc herniations can be cured without surgery (e.g., physiotherapy, activity, painkillers).
CAUSE OF SYMPTOMS
Acute compression of a lumbar nerve root in the spinal canal
Acute compression of all nerve roots in the lumbar spinal canal
SYMPTOMS AND SIGNS
Tingling, numbness, pain or weakness in one leg. This pain usually starts at the lower back.
Numbness, severe pain and weakness in both legs, loss of bladder/bowel control, numbness of the genitals and loss of sexual function (Cauda syndrome)
THE DIAGNOSIS IS BASED ON Medical history Clinical exam
and at least one of the following tests: Magnetic resonance imaging (MRI) Computer tomography Myelography
additionally you may have to do: Radiographs Functional (dynamic) radiographs
Diagnostic nerve root block
Facet joints block Electromyography
Lumbar intervertebral disc herniations are treated either conservatively (non-surgical) or surgically. Most patients (80-90%) with acute pain only improve without surgery within 6 weeks.
Non-surgical treatment may include Nonsteroidal anti-inflammatory drugs Corticosteroids Physiotherapy
Immobilization with belt Physical exercise
Strengthening the back muscles Treatment with heat (Fango)
Therapeutic nerve root block
WHEN SHOULD AN OPERATION BE PERFORMED?
Elective surgery should be considered when a significant muscle weakness (>72 hours) is present or the symptoms (e.g. pain) impair the patient’s quality of life and conservative treatment fails to achieve significant improvement within 6-8 weeks.
Emergency operation should be performed if acute (<72 hours) paralysis, numbness in the genitals and loss of bowel/bladder control due to nerve root compression occurs. In these cases, the best results are achieved if surgery is performed within 12 hours of the onset of symptoms
Emergency surgery should be performed if аcute (<72 hours) loss of strength in a single muscle group due to nerve root compression are present. In this case, it is advisable to perform the surgery within 72 hours of symptoms onset.
WHAT IS THE GOAL OF SURGERY?
To release the compressed nerve roots and/or spinal cord
To preserve the protective function of the spine
To improve symptoms (e.g. pain reduction)
To stop the worsening of the symptoms
HOW IS SURGERY PERFORMED?
Posterior sequestrectomy/nucleotomy for a lumbar disc herniation
WHICH OTHER DISEASES SHOULD BE EXCLUDED (DIFFERENTIAL DIAGNOSIS)? Lower back pain / Lumbar facet joint pain Radiculitis Tumor of the spine
Diseases of the hip or knee Sacroiliac joint pain Peripheral arterial occlusive disease (PAOD) Peripheral nerve compression syndromes A disease of peripheral nerves (e.g. polyneuropathy) Vertebral fractures