The purpose of this information is to enhance your neurosurgical education so that you and your family understand your problem and how surgery will relieve your symptoms.
Normal Anatomy and Physiology
In order to fully comprehend your surgical procedure, it's helpful to have background knowledge of a normal healthy spine. The neck is the upper portion of the spine and is part of a long flexible column known as the spinal column. Twenty-four connected bones (vertebrae) make up this column. The seven bones in your neck are referred to as the cervical spine. These vertebrae look similar to building blocks, since each is stacked atop of each other. Every vertebra is separated by a cushion, which is called an intervertebral disk (also spelled disc).
The outer, thick ring on the edges of the disk is the annulus; the spongy center is the nucleus. The annulus serves as a gasket with a goal to keep the nucleus moist. Because of the soft, gelatin-like centers, the intervertebral disks serve as shock absorbing pads in your neck and prevent the rubbing of one bone against another. Also, these cushions provide the flexibility of your cervical spine, allowing you to turn your head freely.
Attached to the back of these vertebral bodies is a bone arch that provides an open space, the spinal canal, down the spine. This space houses the spinal cord and nerve bundles. The spinal cord itself is bathed in cerebrospinal fluid (fluid that circulates through your spine and brain) and is covered by several protective membranes. At each vertebral level, i.e., each building block of bone, a pair of spinal nerves exit, one to the left and one to the right, off the spinal cord through a small opening called a foramen. These nerves provide the relay of messages to and from the brain, allowing us to move our body and to feel sensation. Nerves that exit through the cervical spine affect the neck, shoulder, arms, and hands. Additionally, muscles and ligaments are attached to the vertebrae and support the spinal cord and nerves.
Understanding the Problem
Numerous cervical spine disorders require surgery for relief of painful symptoms. One of the basic underlying factors associated with most spine disorders is the dehydration of the disks. As we age (starting around 30), the gelatin-like centers dry out and become flattened, causing the vertebrae to lose height and its healthy resilience. With this degeneration, the vertebrae get closer together and cause nerve irritation, which usually stems from a ruptured disc, bone spurs, or stenosis.
Herniated cervical disk is a common neck pain diagnosis. You may have heard some interchangeable terminology: ruptured disk, slipped disc, and herniated nucleus pulposus are the same disorder. With this condition, the center of the nucleus bulges through the annulus and presses on a nerve, resulting in neck or arm pain, or weakness in the arm. Some herniated cervical disks occur from injuries or sudden movements: most (80%) arise spontaneously and often occur at night while sleeping
Bone Spurs & Spinal Stenosis-
With the aging wear and tear of the spine, some patients develop bony outgrowths. These growths are bone spurs, also known as osteophytes. Bone spurs are the body?s natural response to the inflammation that results from the aging spine. The collection of calcium that turns into the bone spur is a type of natural fusion. However, as they grow and extend, the vertebral openings become narrow. Either the spinal canal and/or the foramen, the opening for nerve passageways, become smaller. This narrowing is stenosis, and results in a pinching (compression) of the spinal or cord or the spinal nerve root. Symptoms include pain, weakness, numbness and loss of coordination in the neck or upper extremities.
Anterior Cervical Fusion
Neck movement (vertebral motion) causes the chronic pain. This neurosurgical procedure is performed to relieve the pressure on one or more nerve roots, or on the spinal cord. It involves the stabilization of two or more vertebrae by locking them together (fusing them). The fusion stops the vertebral motion and as a result, the pain is also stopped.
Anterior refers to the front; meaning that the surgeon reaches the cervical spine through a small incision in the front of the neck, usually within a skin fold line under the chin. After retracting neck muscles, the neurosurgeon uses an operating microscope and removes the affected intervertebral disk, which takes the pressure off the nerves or spinal cord. This is called decompression. He then replaces it with a bone graft that will fuse the vertebrae together over time.
A bone graft is a plug of bone that allows the fusion of bone to happen. It is obtained from a bone bank, which collects, treats, and stores bone. The bone comes from human donors who are recently deceased. This type of graft is referred to as allograft bone. The preformed bone plug is safe and will not be rejected by your body. It is acellular, meaning it contains no blood cells.
In some cases, the neurosurgeon may use instrumentation. This terminology refers to metal plates or pins that may be necessary to provide extra pressure and support to the neck and to make sure that the bones fuse adequately.
A cervical fusion procedure takes between 2 and 6 hours. The length of time depends upon the number of vertebrae involved, whether instrumentation is indicated, and other factors.
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