Application Of Neurosurgery
Current neurosurgery includes trephination along with other procedures to correct not only injury and disease of the central nervous system, but also to modify nerve supply to other areas of the body that may benefit from such surgery and to enhance blood supply to the brain. A number of conditions are commonly treated by neurosurgery. Injuries of the skull, brain, vertebral column and spinal cord are common diagnoses in neurosurgery and are most commonly caused by motor vehicle accidents or sports accidents.
Injury to the head or spinal column may result in swelling of the enclosed nervous tissues, bleeding inside the skull that would place pressure on a localized area of the brain, or may involve bone fragments impinging on the brain or spinal cord as a result of a blow to the head or back. Certain congenital conditions such as hydrocephalus (excessive fluid on the brain) or spina bifida (a condition in which the spine has not closed around the spinal cord) frequently are treated by the neurosurgeon. Premature closure of the skull, which will prevent the skull from expanding as the brain grows, also requires surgery to separate the skull bones.
Tumor growth in the skull or spinal column may also require surgical correction. A benign (noncancerous) tumor in the brain is usually well defined and can be removed by delicate surgery. A malignant (cancerous) tumor presents a much more challenging problem because it is not defined as clearly or contained as well as the benign growth. Still, some areas of the brain remain unreachable by surgical tools and a growth in those areas cannot be removed. In that case, the physician may resort to radiation therapy or the use of antitumor drugs.
The brain requires an especially copious blood supply. Large arteries in the side and back of the neck carry blood to the brain, but when these arteries become narrowed or blocked by fatty deposits (a condition called atherosclerosis), the blood supply to the brain may be reduced to an insufficient amount. A balloon catheter may be used by the physician to clear the blockage. In this procedure, called angiography, a catheter is guided to the site of blockage. The tiny balloon on the end of the catheter is inflated to press the blockage out of the way. The balloon is then deflated, and the catheter removed. In the event this procedure is not effective, the surgeon may need to operate on the blood vessels instead of the brain itself. A graft to bypass the blocked area may be called for or the vessel may be opened and the deposit removed (a procedure called endarterectomy) if the artery is accessible. In addition, an artery can balloon from the pressure of the blood within it. This is called an aneurism, and it forms at the site of a weak spot in the arterial wall. The swollen artery in itself may do no harm, but the weakened arterial wall can burst at any time, allowing the escape of blood into the brain. This is one form of stroke. If the artery is accessible, the surgeon can remove the weak area and sew the ends of the artery together again. If the artery cannot be reached for surgical correction, some means can be taken to reinforce the arterial wall from within.
A so-called slipped disk or ruptured disk, damage to one of the cartilaginous disks between the vertebrae, may form a protrubance into the spinal canal that impinges on the spinal cord. This may cause pain or even the inability to walk normally. Here again, the neurosurgeon may need to take steps to remove the protrusion and in some cases fuse the vertebrae to prevent their flexing on the weakened disk.
In cases of intractable pain or involuntary movements that cannot be corrected, the surgeon may be called upon to interrupt the nerve supply to a given area. This function is being taken over more and more by medical therapy as physicians learn new information about nerve functions and how to interrupt them medicinally, but the surgeon still provides a needed service.
Locating a tumor or area in which blood has been released inside the skull requires a rigorous diagnostic procedure. If the patient has had an accident such as a fall or automobile wreck in which he struck his head, the surgeon may be more aware of the possibility of the existence of a blood clot forming on the brain, bone fragments that may be impinging on the brain, or swelling of the brain. If the patient denies any accidental trauma to the head, but has had persistent and longstanding headaches, visual disturbances, dizziness, or other lingering symptoms, the surgeon is alerted to the possibility of an aneurism or other source of blood leakage or a developing tumor.
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