Benign tumour: slow growth, non-infiltrative
character, low recurrence rate, amenable to complete surgical removal
(depending on location), usually does not require adjuvant radiotherapy or
a clear, colourless fluid in which the central nervous system is, and
which is also present in the chambers of the brain. It acts as a
cushion for the brain and spinal cord, and due to immersion, the weight
of the brain is greatly reduced. It also acts as a medium through which
harmful substances are removed by the one way traffic to blood, as well
as serving as a transport medium for hormones and other substances.
Computed tomography scanner:
special scanner based on ionising radiation—x-ray beams are channelled
through many planes in order to get high resolution pictures with good
bony-structure representation. Quick, relatively cheap, and more
widely available. (http://www.radiologyinfo.org/en/info.cfm?PG=headct)
Contrast enhancement: this is the
injection of special substances during magnetic resonance and/or computed
tomography scans which can significantly aid in identifying tumours and
Fibre-tracking: this is a special
neuronavigation technique where it is possible to project the course of
neural pathways within the vicinity of the proposed operation site.
resonance imaging: a special brain mapping technique where areas of the
brain responsible for crucial functions like speech and arm and leg function
can be visually identified, thereby permitting the neurosurgeon to exercise
maximum caution by guiding extent of permissible tumour removal without
compromise of function in those sensitive areas.
Gammaknife surgery: this is based on the
principle of focussing a large number of radiation beams on a small,
predetermined area in order to destroy tumour cells. Surrounding
tissue remains undamaged, as the critical dose of radiation is achieved only
in the planned vicinity where the gamma radiation beams intersect.
collective name for tumours arising from glial cells—these are cells
which nerve cells provide support and nutrition, help in maintaining
metabolic balance, aid in the formation of nerve sheaths, and take part
in signal transmission.
“science of tissue”—in this context meaning the cellular characteristics
of the tumour process in question
magnetic resonance imaging scanner: this permits real-time control
and guidance of tumour removal during the operation itself. (http://www.radiologyinfo.org/en/info.cfm?PG=headmr)
Malignant tumour: fast growth, infiltrative
character, high recurrence rate—often with a higher degree of malignancy,
usually requires surgical treatment in conjunction with adjuvant
radiotherapy and/or chemotherapy. They carry a relatively negative
prognosis, with the primary difference between the various grades of
malignancy being length of life-expectancy.
tomography scanner: special scanner based on the use of a powerful
magnet many times the strength of the Earth’s gravitational field used to
get high resolution pictures in three planes with good soft-tissue
representation. Slow, relatively expensive, and not so widely
available. No ionising radiation involved. (http://www.radiologyinfo.org/en/info.cfm?PG=headmr)
- Metastases: the
local or distant spread of tumour cells.
Motor deficit: muscle weakness, decrease in
Necrosis: is essentially “dead tissue” or
Neuronavigation: special markers similar
to stickers are placed in various locations on the head and behind both ear,
and scans—either magnetic resonance, or computed tomography, or both--are
then performed. This then allows the neurosurgeon to “navigate” during
the operation using a sophisticated computer setup with an interactive
program and a special pointer using these points as reference frames, and
with a three-dimensional representation of the tumour.
electroencephalography (graphical representation of the electrical activity
of the brain), evoked potentials (electrical
potential recorded following presentation of a stimulus): brainstem auditory evoked
potentials, motor evoked potentials, sensory evoked potentials, visual
evoked potentials—these are used peri- and intraoperatively to assess and
control nerve function.
Positron emission tomography: a
special scan performed after the administration of a small quantity of
radioactive substance. (http://www.radiologyinfo.org/en/info.cfm?PG=pet)
Space-occupying lesion: any formation
or growth within the skull which causes what is known as a
mass-effect—meaning exertion of pressure on surrounding structures
with/without consequent of a raise in intracranial pressure.
Sensory deficit: altered or diminished
Stereotactic biopsy: this is a diagnostic
option where special scans are made using a stereotactic frame, and
following careful preparation and calculation of several measurements, the
equivalent of a “key-hole” operation is performed with the aim to take
tissue samples for a biopsy.