Neck and Back

Herniated Disk

Anatomy

The spinal column is made up of small bones (vertebrae) stacked on top of one another, creating the natural curves of the back. Between the vertebrae are flat, round, rubbery pads (intervertebral disks) that act as shock absorbers and allow the back to flex or bend. Muscles and ligaments connecting the vertebrae allow motion while providing support and stability for the spine and upper body. Each vertebra has an opening (foramen) in the center and these line up to form the spinal canal. Protected by the vertebrae, the spinal cord and other nerve roots travel through the spinal canal. Nerves branch out from the spinal column through vertebral openings, carrying messages between the brain and muscles. Facet joints align at the back of the spinal column, linking the vertebrae together and allowing for rotation and movement. Like all joints, cartilage covers the surface where facet joints meet.

The spine contains three segments: lumbar, thoracic and cervical. The lumbar spine consists of five vertebrae located in the lower back; lumbar vertebrae are larger because they carry more of the body's weight. The thoracic spine consists of 12 vertebrae and begins at the upper chest, extending to the middle back and connecting to the rib cage. The cervical spine includes the neck and consists of seven small vertebrae, beginning at the base of the skull and ending at the upper chest. Disks in the lumbar spine are composed of a thick outer ring of cartilage (annulus) and an inner gel-like substance (nucleus). In the cervical spine, disks are similar but smaller in size.

Description

In children and young adults, intervertebral disks have a high water content. As we age, they dry out, causing them to stiffen, weaken and become less flexible. The disks settle, or collapse, and lose height and begin to bulge; the spaces between the vertebrae become narrower. A disk herniates when part of the center nucleus pushes through the outer edge of the disk and back toward the spinal canal. This puts pressure on the nerves. Spinal nerves are very sensitive to even slight amounts of pressure, which can result in pain, numbness or weakness in one or both legs. A herniated disk, often referred to as a "slipped" or "ruptured" disk, is a common source of pain in the neck, lower back, arms or legs.

Cause

Factors that can weaken the disk and increase your risk for a herniated disk include: improper lifting, smoking, excessive body weight that places added stress on lumbar disks, sudden pressure (which may be slight), and repetitive strenuous activities.

Symptoms

Symptoms of a herniated disk include: weakness in one leg; a tingling, prickling or "pins and needles" sensation (paresthesia) or numbness in one arm, leg or buttock; or burning pain centered in the shoulder, neck or arm. Loss of bladder or bowel control is also a symptom, but if this is combined with significant weakness in both arms or legs, the problem could be serious—you should seek immediate medical attention.

• Lower back—Low back pain affects four out of five people, however, pain alone is not enough to recognize a herniated disk. See your physician if back pain results from a fall or a blow to your back. The most common symptom of a herniated disk is sciatica—a sharp, often shooting pain that extends from the buttocks down the back of one leg. Sciatica is caused by pressure on the spinal nerve.
• Neck—Neck pain is also a common symptom of herniated disk. You may have a herniated disk if pressure placed on a nerve in the neck causes pain in the muscles between your neck and shoulder (trapezius muscles). Pain may shoot down the arm and the pain may also cause headaches in the back of the head.

Diagnosis

After reviewing your medical history and discussing your symptoms, your physician will perform a physical examination. Be sure to mention any injuries, as well as any neck or back pain accompanied by gradually increasing arm or leg pain. The physical exam will help determine which nerve roots are affected (and how seriously). An X-ray may reveal evidence of disk or degenerative spine changes. Additional imaging studies, such as magnetic resonance images (MRI), electromyelography (EMG), or computed tomography (CT) may be required to fully assess and diagnose your condition.

Nonsurgical Treatment

Nonsurgical treatment is effective in treating the symptoms of herniated disks in more than 90% of patients. Most neck or back pain will resolve gradually with simple measures. Rest and over-the-counter pain relievers may be all that is needed. Muscle relaxers, analgesics, and anti-inflammatory medications are also helpful. Cold compresses or ice can also be applied several times a day for no more than 20 minutes at a time. After any spasms settle, gentle heat applications may be used.

Any physical activity should be slow and controlled, especially bending forward and lifting. Avoid sitting for long periods, and consider taking short walks. These can help ensure that symptoms do not return. A spine conditioning program or low back exercises may also be recommended to strengthen back and abdominal muscles. For the neck, exercises or traction may also be helpful. It is essential that you learn how to properly stand, sit and lift in order to avoid future episodes of pain. If these nonsurgical treatment measures fail, epidural injections of a cortisone-like drug may be given on an outpatient basis over a period of weeks to lessen nerve irritation and allow more effective participation in physical therapy.

Surgery

Surgery may be required if a disk fragment lodges in the spinal canal and presses on a nerve, causing significant loss of function. Surgical options in the lower back include microdiskectomy or laminectomy, depending on the size and position of the disk herniation. For some patients, artificial disk replacement (ADR) may also be considered. In the neck, an anterior cervical diskectomy and fusion are usually recommended. This involves removing the entire disk to take the pressure off the spinal cord and nerve roots. Bone is placed in the disk space and a metal plate may be inserted to stabilize the spine. For some patients, a smaller surgery that does not require fusing the bones together may be performed on the back of the neck. The patient is under general anesthesia for each of these surgical procedures. They may be performed on an outpatient basis or require an overnight hospital stay. You should be able to return to work in 2 to 6 weeks after surgery.

Complications

As with any surgery, there are some risks, and these vary from person to person. Complications are typically minor, treatable and unlikely to affect your final outcome. For most people, surgery can provide relief of symptoms and return to function with relatively low risk of complications. Overall, elderly patients have higher rates of complications from surgery, as do patients who are overweight, diabetics, smokers, or suffering from multiple medical problems. Among the general, potential risks associated with surgery are infection, bleeding and blood clots, and reactions to anesthesia. Be sure to discuss the potential risks and benefits with your surgeon prior to surgery.