INVESTIGATIVE TECHNIQUES IN NEUROSURGERY

As in every other brand of medicine, the essential first step is a detailed history of the patient's symptoms and how they have developed, followed by a careful physical examination. In addition to these basics, recent advances in neuro-imaging have revolutionized neurosurgery. These include:

Computed axial tomography scanning (CT)

        A special scanner uses x-rays and computer software to produce 'slices' in cross-section through the brain or spinal cord at different levels.     Abnormalities such as bleeding or tumours can easily be detected. The bone of the skull and spine can also be seen clearly. Modern scanners produce images rapidly, and CT scanning is used to evaluate acutely ill neurosurgery patients.

Magnetic resonance (MR) imaging

        This relatively new method uses a combination of a strong magnetic field and radio waves, rater than x-rays, to produce very detailed, high quality images of the brain and spinal cord. Many features not visible on CT are seen clearly on MR, which is the current 'gold standard' for neuro-imaging. However, scanning times are longer than for CT. This, and other technical factors, limit its use at the moment to the most acutely ill patients, although technological advances are beginning to change this.

Angiography

        This is a method of studying the blood vessels of the brain and the spinal cord, using x-rays and injections of a contrast medium ( a substance which allows the vessels to be clearly outlined).

Tools of the trade

        The neurosurgeons need drills and bone rongeurs ('nibblers') to cut through the thick bone of the skull or vertebrae. However, once inside, delicate manipulation of the brain and spinal cord is essential. The development of the operating microscope has transformed neurosurgery. Under magnification, tiny abnormalities such as aneurysms can clearly be seen, along with the surrounding anatomy, and operated on in relative safety. Many operations are now performed using the microscope and specially designed micro-instruments. This technique is called microneurosurgery.