Lumbar disc disease accounts for a large amount of lost productivity in the workforce. Accurate diagnosis can be difficult and often requires interpretation. Treatment is controversial. Treatment failures are not uncommon, are often related to posttraumatic or work-related injuries, and may result in litigation. As a consequence, this disease can generate distrust of physicians on the part of patients and vice versa. Surgical treatment was not widespread until the 1950s. Today, lumbar discectomy is one of the most commonly performed elective operations in the United States.
Lumbar disc disease is a rather encompassing term. For example, some physicians include back pain alone as a symptom of disc disease. Others make the diagnosis without evidence of disc disease on MRI. The discussion of this article is limited to well-defined lumbar disc herniation. The pathophysiology, clinical presentation, radiographic diagnosis, treatment, and outcome are discussed.
A disc herniation (lumbar disc disease) most frequently irritates the displaced nerve root. One of the more difficult concepts for beginning medical students to grasp is the anatomic relationship of the fifth lumbar (L5) nerve root to the L4-5 disc herniation. Equally important to understand is the concept of the far lateral or foraminal disc herniation in which the root above the disc herniation is irritated.
With very large herniations, the entire cauda equina can be compressed and functionally compromised.
This causes saddle anesthesia and can cause urinary retention and incontinence.
A herniated disk fragment comes from the nucleus pulposus of the disc (a remnant of the embryonic notochord). In the normal condition, this nucleus is in the disk center securely contained by the annulus fibrosus. When a fragment of nucleus herniates, it irritates and/or compresses the adjacent nerve root. This can cause the pain syndrome known as sciatica and, in severe cases, dysfunction of the nerve. Although most people experience back pain during their lifetime, only a fraction experience lumbar radiculopathy or sciatica as a consequence of root compression or irritation. Almost 5% of males and 2.5% of females experience sciatica at some time in their lifetime.
MRI is by far the most commonly ordered test to evaluate patients with sciatica. Often, MRI is performed prior to plain radiographs. MRI is very sensitive in delineating lumbar disc herniations. Far lateral discs are best evaluated with this test. In reoperations, MRI can delineate the full extent of scar tissue and, with moderate reliability, differentiate it from recurrent disc herniation.
Lumbar discectomy is the most common operation performed in the United States for lumbar-related symptoms. Almost all patients with sciatica and disc herniations deserve a trial of medical therapy. The one obvious exception is a patient presenting with cauda equina syndrome or profound motor deficits. a large multicenter trial found that surgical and nonsurgical outcomes at 2 years were similar, but that the surgical group experienced faster pain relief.
The limitations of this study are outlined in an editorial.
See the images below of herniated disc disease.
Degenerated lumbar disc disease.
Magnetic resonance image of a herniated nucleus pulposus of the lumbar spine.
Degenerative lumbar disc disease. The various forces placed upon the discs of the lumbar spine that can result in degenerative changes.