Glossary of Terms
To use this glossary, click on the letter to the left that corresponds
to the word you are looking for. Otherwise, use the scroll bar on
the right to browse through the entire glossary.
A
Acute - Severe, for a short time.
Adenocarcinoma - Cancer arising from secretory cells, often in
a gland. Breast and pancreatic cancers are usually adenocarcinomas.
Afferent Neuron - Transmitting impulses to the central nervous
system.
Allograft Bone - Sterile bone derived from another human which
is used for grafting procedures.
Analgesia - Loss of sensibility to pain, loss of response to a
painful stimulus.
Anesthetics - Modern anesthetics are designed to
keep the patient comfortable and pain free during surgery. Local
anesthetics are injections near the procedure site. Locals work
by blocking the pain signals sent to the brain. General anesthetics
temporarily affect the nervous system by disabling nerve impulses.
In other words, the patient is asleep and pain free. For open back
procedures, general anesthetics are primarily used.
Anesthesiologist - Physician who administers pain-killing medications
during surgery.
Anterior - The front portion of the body. It is often used to indicate
the position of one structure relative to another.
Anterior Cervical Discectomy - A surgery in which a intervertebral
disc in the neck is removed. Generally the space is replaced by
a bone graft and may include a metal plate to help support the spine
while the fusion heals.
Anterior Lumbar Interbody Fusion (ALIF) - A surgery in which
an intervertebral disc is completely removed and the remaining space
is filled with bone to obtain a spinal fusion.
Annulus Fibrosus - The outer, fibrous, ring-like portion of an
intervertebral disc.
Anterolateral - Situated or occurring in front of and to the side.
Arachnoid - Delicate, web-like middle layer of membranes that cover
the brain and spinal cord.
Arachnoiditis - Inflammation of the arachnoid membrane.
Arthralgia - Joint pain.
Arthritis - Inflammation of a joint usually characterized by swelling,
pain and restriction of motion.
Arthrodesis - The fusion of bones across a joint space, thereby
limiting or eliminating movement. It may occur spontaneously or
as a result of a surgical procedure, such as fusion of the spine.
Arthropathy - Any disease or disorder involving a joint.
Arthroplasty - The surgical remodeling of a diseased or damaged
joint.
Arthroscope - An instrument inserted into a joint cavity to view
the interior of a joint and correct certain abnormalities. An arthroscope
is an endoscope for use in a joint.
Arthroscopy - The procedure of visualizing the inside of a joint
by means of an arthroscope.
Articular - Pertaining to a joint.
Astrocyte - A star-shaped cell, comparatively large which supports
the nerve cells (neurons) of the brain and spinal cord.
Astrocytoma - A tumor of the brain composed of astrocytes. It is
marked by slow growth, lump (cyst) formation and invasion of surrounding
structures. Often, a highly cancerous tumor called glioblastoma
grows within the tumor. Complete removal of an astrocytoma by surgery
may be possible early in the growth of the tumor. Also called astrocytic
glioma.
Ataxia - An inability to coordinate voluntary muscle movements.
Autogenous Bone - Bone originating from the same individual; i.e.,
an individual's own bone.
Autograft Bone - Bone transplanted from one part to another part
of the body in the same individual.
Autonomic Nervous System - The involuntary nervous system that
also innervates smooth and cardiac muscle and glandular tissues.
Axon - The part of a nerve cell that transmits signals to other
structures or nerves.
B
Backbone - See Spine.
Biocompatibility - A characteristic of some materials that when
they are inserted into the body do not produce a significant rejection
or immune response.
Biodegradation - The breakdown of organic materials into simple
chemicals commonly found in the body.
Bone - The hard tissue that provides structural support to the
body, It is primarily composed of hydroxyapatite crystals and collagen.
Individual bones may be classed as long, short, or flat.
Bone Derivative - One of the substances extracted from bone, such
as bone morphogenic proteins (BMP).
Bone Graft - Bone which is harvested from one location in an individual
and placed in another individual (allograft bone) or in a different
location in the same individual (autogenous bone).
Bone Harvesting - The procedure in which bone is taken from
another part of the patient's body (usually the pelvis) for use
in a fusion procedure.
Bone Marrow - The tissue contained within the internal cavities
of the bones. A major function of this tissue is to produce red
blood cells.
Bone Plate - Usually a relatively thin metal device which is affixed
to bone via screws. Bone plates are used to immobilize bones or
bone fragments such that healing can occur.
Bone Screw - A threaded metal device which is inserted into bone.
The functions of bone screws are to immobilize bones or bone fragments
or to affix other medical devices, such as metal bone plates, to
bones.
C
Cancellous Bone - The spongy or honeycomb structure of some bone
tissue typically found at the ends of long bones.
Carcinoma - Type of tumor that arises from cells which ocver on
line body surfaces of internal organs and passageway of the body.
Skin, intestinal, uterine and lung cancers are carcinomas.
Cartilage - The hard, thin layer of white glossy tissue that covers
the end of bone at a joint. This tissue allows motion to take place
with a minimum amount of friction.
Cauda Equina - A bundle of spinal nerve roots arising from the
end of the spinal cord and filling the lower part of the spinal
canal.
Central Nervous System - Part of the nervous system which consists
of the brain and spinal cord, to which sensory impulses are transmitted
and from which motor impulses pass out, and which supervises and
coordinates the activity of the entire nervous system.
Centrum - The body of a vertebra.
Cerebrospinal Fluid - Water-like fluid produced in the brain that
circulates and protects the brain and spinal cord, known as CSF.
Cervical - The neck region of the spine containing the first seven
vertebrae.
Chemonucleolysis - A treatment of an intervertebral disc that consists
of an injection of chymopapain, a drug that dissolves part of the
disc.
Choroid Plexus - A vascular portion of the brain in the ventricles
that secretes cerebrospinal fluid.
Clinical Studies - A process of strictly controlled evaluations
involving patients. Some of these studies are required by the FDA
prior to general release of a device or compound for use in humans.
Cobalt-Chrome - A term that is used in referring to cobalt-chromium-molybdenum
alloy, a mixture of metals used in many surgical implants.
Coccyx - The region of the spine below the sacrum. It is also known
as the tailbone.
Collagen - A fibrous protein which is a major constituent of connective
tissue. Such as skin, tendons, ligaments, cartilage, and bones.
Comminuted Fracture - A fracture in which a bone is broken into
more than two pieces. Often internal or external fixation devices
are used to maintain proper alignment of the fragments.
CT - (Computed Tomography) A computer enhanced x-ray study to detect
structural abnormalities. A three-dimensional map of soft tissue
or bone is imaged.
Contrast Medium - A material used during a radiologic procedure
to define a structure.
Cortical Bone - The dense bone that forms the outer surface of
bone.
D
De-mineralized Bone - Bone tissue which has been depleted of its
minerals; e.g., calcium and phosphorous.
Dendrite - A nerve cell process that transmits impulses toward
the cell body.
Dens - Part of the bone structure of the second spinal vertebra
(C2), the second bone in the neck. The dens protrudes into a ring-like
structure on C1, providing both stability and motion to the neck.
Disc (Intervertebral) - The tough, elastic structure that is between
the bodies of spinal vertebrae. The disc consists of an outer annulus
fibrosus enclosing an inner nucleus pulposus.
Disc Degeneration - The loss of the structural and functional integrity
of the disc.
Discectomy - Surgical removal of part or all of an intervertebral
disc.
Distal - Situated away from the center of the body.
E
Endogenous - Arising within or derived from the body.
Endoscope - A medical device for viewing internal portions of the
body through a small incision. It is usually comprised of fiber
optic tubes and video display instruments.
Endoscopic Surgery - Surgery in which an endoscope is used
to see the inside of the body and to provide a channel for surgical
instruments, allowing surgery to be done with minimal disruption
of body tissues.
Endoscopy - Inspection of internal body structures or cavities
using an endoscope.
Ependymoma - A tumor make up of specialized cells for the lining
(ependyma) of the chambers of the brain. Also called ependymocytoma.
Epidural - Situated outside the thin, tough dural membrane that
surrounds the brain and spinal cord.
Excision - Removal by cutting away material.
Exogenous - Originating outside of the body.
F
Facet - A posterior structure of a vertebra which articulates with
a facet of an adjacent vertebra to form a facet joint that allows
motion in the spinal column. Each vertebra has two superior and
two inferior facets.
Facetectomy - Excision of a facet.
Fatigue Fracture - A fracture that occurs in bone or in other materials.
Including metal, as a result of repeated stress as opposed to a
single injury.
Fibrosis - The replacement of normal tissue with scar tissue.
Food and Drug Administration (FDA) - The Federal government agency
that has regulatory authority over the manufacture, distribution,
and labeling of drugs, medical devices, and foods.
Foramen - A natural opening or passage in bone.
Foraminotomy or Foraminectomy - Surgical opening or enlargement
of the opening in the vertebra where the nerve root leaves the spinal
cord.
Fracture - A disruption of the normal continuity of bone.
Fusion - Union or healing of bone (see Arthrodesis).
G
Gamma Knife - Equipment that delivers a precise concentrated dose
of radiation to a predetermined target using gamma rays.
Glia - The major support cells of the brain, involved in the nutrition
and maintenance of nerve cells.
H
Herniated Disc - Extrusion of part of the nucleus pulposus material
through a defect in the annulus fibrosus.
Heterotopic Bone Formation - The occurrence of bone growth in an
abnormal location.
Hook - For spinal applications, a metallic medical device used
to connect spinal structures to a rod.
Hydroxyapatite (HA) - The lattice-like structure of bone composed
of calcium and phosphorous crystals which deposits on collagen to
provide the rigid structure of bone.
I
Iliac Bone - A part of the pelvic bone that is above the hip joint
and from which autogenous bone grafts are frequently obtained.
Iliac Crest - The large, prominent portion of the pelvic bone at
the belt line of the body.
Immobilization - Limitation of motion or fixation of a body part
usually to promote healing.
Intervertebral Disc - See Disc (Intervertebral).
In vitro - Describing biological phenomena that are made to occur
outside the living body (traditionally in a test tube). In vitro
is Latin for in glass.
In vivo - Within a living body. In vivo is Latin for in life.
Inferior - Situated below or directed downward.
Informed Consent - Consent of the patient who has received sufficient
information to have surgery, receive medication, or participate
in a clinical study.
Institutional Review Board (IRB) - A committee designated by an
institution, such as a hospital, to review and approve research
projects; e.g., clinical studies in that institution.
Internal Fixation - The immobilization of bone fragments or joints
with implants in order to promote healing or fusion.
Investigational Device Exemption (IDE) - A FDA regulatory status
which permits the human use of an unapproved medical device for
the purposes of collecting clinical data under strictly controlled
conditions.
Intradiscal Electrothermal Therapy (IDET) - A new, experimental,
minimally invasive treatment of pain due to disc degeneration in
which controlled levels of thermal energy (heat) are applied to
a degenerated disc section.
Intradural - Within or enclosed by the dura mater, which is the
tough, fibrous membrane that forms the outer layer of the spinal
cord and brain.
Intramedullary - Within the spinal cord.
Intramedullary Tumors - Tumors that grow inside the spinal cord
or individual nerves
J
Joint - The junction or articulation of two or more bones that
permits varying degrees of motion between the bones.
K
Kyphoplasty - a minimally invasive surgical technique that
creates a cavity in a vertebral body into which bone cement is inserted
in order to provide solid support for a collapsed or damaged vertebra.
Kyphosis - An abnormal increase in the normal kyphotic curvature
of the thoracic spine.
L
Lamina - An anatomical portion of a vertebra. For each vertebra,
two lamina connect the pedicles to the spinous process as part of
the neural arch.
Laminectomy and laminotomy - An operation for removal of part or
all of the lamina of a vertebra. Commonly performed in order to
be able to remove an intervertebral disc protrusion or to decompress
a nerve root.
Laser - Light Amplification by Stimulated Emission of Radiation.
The device that produces a focused beam of light at a defined wavelength
that can vaporize tissue. In surgery, lasers can be used to operate
on small areas without damaging delicate surrounding tissue.
Lateral - Situated away from the midline of the body.
Ligament - A band of flexible, fibrous connective tissue that is
attached at the end of a bone near a joint. The main function of
a ligament is to attach bones to one another, to provide stability
of a joint, and to prevent or limit some joint motion.
Lordosis - An abnormal increase in the normal lordotic curvature
of the lumbar spine.
Lumbago - A non-medical term signifying pain in the lumbar region.
Lumbar - The lower part of the spine between the thoracic region
and the sacrum. The lumbar spine consists of five vertebrae.
M
Medial - Situated closer to the midline of the body.
Medical Device Report (MDR) - The required reporting of' medical
device complaints involving a patient death, serious injury, or
device malfunction.
Meningiomas - A tumor of the meningeal membranes covering the brain
and spinal cord. Meningiomas often grow slowly. They usually contain
blood vessels. The tumors may vary in shape and structure. They
may invade the skull, causing weakening of the bones and pressure
on the brain tissue. Meningiomas usually occur in adults. They follow
in some cases after a head injury.
Minimally Invasive Surgery - Surgery requiring small incision(s),
usually performed with endoscopic visualization.
N
Neurosurgery - The surgical specialty involved in the treatment
of disorders of the brain, spinal cord, and peripheral nerves.
Nerve Root - The portion of a spinal nerve in close proximity to
its origin from the spinal cord.
Neural Arch - The bony arch of the posterior aspect of a vertebra
that surrounds the spinal cord, also referred to as the vertebral
arch.
Neurofibroma - A fiberlike growth of nerve tissue. Many growths
of this type in the nervous system are often linked to many defects
in other tissues.
Non-Union - Failure of the fragments of a fractured bone to heal
or to obtain bony fusion following an arthrodesis.
Nucleus Pulposus - The semi-gelatinous tissue in the center of
an intervertebral disc. It is surrounded and contained by the annulus
fibrosus which prevents this material from protruding outside the
disc space.
O
Orthopaedics (also Orthopedics) - The medical specialty involved
in the preservation and restoration of function of the musculoskeletal
system that includes treatment of spinal disorders and peripheral
nerve lesions.
Orthopaedic Implants - Medical devices used to replace or provide
fixation of bone or to replace articulating surfaces of a joint.
Ossification - The process of forming bone in the body,
Osteoporosis - A disorder in which bone is abnormally brittle,
less dense, and is the result of a number of different diseases
and abnormalities.
Osteosarcoma - A primary cancer which arises from the bone-forming
cells and is most often seen in young people between 10 and 25 years
of age.
P
Pathology - The study of disease states.
Pedicle -The part of each side of the neural arch of a vertebra.
It connects the lamina with the vertebral body.
Periosteum - A fibrous membrane that covers the surface of bone
except at the end of the bones where it is covered with cartilage
as part of a joint. In children, periosteum is involved in forming
new bone and molding the configuration of bone; and in the adult,
the periosteum forms new bone secondary to injury or infection.
Physical Therapy - The treatment consisting of exercising specific
parts of the body such as the legs, arms, hands or neck, in an effort
to strengthen, regain range of motion, relearn movement and/or rehabilitate
the musculoskeletal system to improve function.
Physiology -The science of the functioning of living organisms,
and of their component systems or parts.
Posterior - Located behind a structure, such as relating to the
back side of the human body.
Posterior Lumbar Interbody Fusion (PLIF) - The surgical removal
of an intervertebral disc, approaching the disc from the back side
of it, after which bone graft or metal cage implant is placed into
the space in order to create a spinal fusion.
Powered Surgical Instruments - Instruments which are powered by
compressed air or electricity and are used in surgical procedures
to cut, drill, or otherwise remove bone and cartilage, as well as
to evacuate fluids.
Pre-Clinical Studies - Tests occurring prior to clinical studies,
usually in vitro or in vivo involving animals. The purpose of these
studies is to determine the safety and efficacy of the test material.
Premarket Approval (PMA) - A regulatory method for gaining a marketing
clearance from the FDA for a Class III medical device. A company
submits information to the FDA that documents the safety and effectiveness
of the device.
Proximal - Nearest the center of the body.
Pseudoarthrosis (also Pseudarthrosis) - A form of non-union in
which there is the formation of a false joint with some cartilage
covering the ends of the bones and a cavity containing fluid that
resembles a normal joint.
Q
Quadriplegia - Paralysis of all four limbs.
R
Radiation Oncologist - A physician who specializes in the use
of radiant substances, such as x-rays and radioactive isotopes to
diagnose and treat diseases.
Resection - The surgical removal of part of a structure, such as
bone.
Resorption - The removal of bone tissue by normal physiological
process or as part of a pathological process such as an infection.
Rod - In spinal applications, a slender, metal implant which is
used to immobilize and alien the spine.
Ruptured Disc - See Herniated Disc.
S
Sacrum - A part of the spine that is also part of the pelvis.
It articulates with the ilia at the sacroiliac joints and articulates
with the lumbar spine at the lumbosacral joint. The sacrum consists
of five fused vertebrae that have no intervertebral discs.
Sagittal - Longitudinal.
Schwannomas - A harmless, single, self-contained tumor arising
in the coverings of certain nerves. Also called Schwann cell tumor,
neurilemoma.
Sciatica - A lay term indicating pain alone the course of a sciatic
nerve, especially noted in the back of the thigh and below the knee.
Scoliosis - Lateral (sideways) curvature of the spine.
Sepsis - A state of infection of tissue due to disease-producing
bacteria or toxins.
Skeleton - The rigid framework of bones that gives form to the
body, protects and supports the soft organs and tissues, and provides
attachments for muscles.
Spinal Canal - The bony channel that is formed by the intravertebral
foramen of the vertebrae and in which contains the spinal cord and
nerve roots.
Spinal Column - See Spine.
Spinal Cord - The longitudinal cord of nerve tissue that is enclosed
in the spinal canal. It serves not only as a pathway for nervous
impulses to and from the brain, but as a center for carrying out
and coordinating many reflex actions independently of the brain.
Spinal Disc - See Disc (Intervertebral).
Spinal Fusion - A surgical procedure to permanently join bone by
interconnecting two or more vertebrae in order to prevent motion
(see Arthrodesis).
Spinal Instrumentation - Metal devices such as rods, plates,
screws, cables, wires, etc. that are implanted in the spine to help
correct deformities or support the spine in order for a fusion to
take place.
Spinal Osteotomy - A surgical procedure in which a vertebra
is cut or broken in order to permit a correction of a deformity.
Metal devices may be used to support the spine afterwards.
Spinal Stenosis - Reduction in the diameter of the spinal canal
due to new bone formation which may result in pressure on the spinal
cord or nerve roots.
Spine - The flexible bone column extending from the base of the
skull to the tailbone. It is made up of 33 bones, known as vertebrae.
The first 24 vertebrae are separated by discs known as intervertebral
discs, and bound together by ligaments and muscles. Five vertebrae
are fused together to form the sacrum and 4 vertebrae are fused
together to form the coccyx. The spine is also referred to as the
vertebral column, spinal column, or backbone.
Spinous Process - The portion of the vertebrae that protrudes posteriorly
from the spinal column. The spinous processes create the "bumps"
felt on the midline of the back.
Spondylitis - Inflammation of vertebrae.
Spondylolisthesis - A defect in the construct of bone between the
superior and inferior facets with varying degrees of displacement
so the vertebra with the defect and the spine above that vertebra
are displaced forward in relationship to the vertebrae below. It
is usually due to a developmental defect or the result of a fracture.
Spondylolysis - Displacement of one vertebrae over another with
fracture of a posterior portion of the vertebra. A defect in the
neural arch between the superior and inferior facets of vertebrae
without separation at the defect and therefore no displacement of
the vertebrae. It may be unilateral or bilateral and is usually
due to a developmental defect but may be secondary to a fracture.
Stainless Steel - Iron-based metal containing chromium that is
highly resistant to stain, rust, and corrosion. Certain grades of
stainless steel are commonly used to make surgical implants and
instruments.
Sterile - Free from living organisms.
Sterilization - The method used to render a material free from
living organisms. Usual methods include steam under pressure, gas,
and ionizing radiation.
Superior - Situated above or directed upward toward the head of
an individual.
T
Tendon - The fibrous band of tissue that connects muscle to bone.
It is mainly composed of collagen.
Thoracic - The chest level region of the spine that is located
between the cervical and lumbar vertebrae. It consists of 12 vertebrae
which serve as attachment points for ribs.
Titanium - A metallic element used to make surgical implants.
Toxicology - The study of the toxic or harmful effects of substances
on the body.
Transforamenal Lumbar Interbody Fusion (TLIF) - Similar to PLIR,
this is a surgical removal of an intervertebral disc, approaching
the disc from one or both sides of the disc, after which bone graft
or metal cage implant is placed into the space in order to create
a spinal fusion.
Transplant - The implantation of bone tissue, as in grafting, from
one part of the body to another. Transplant also refers to the transfer
of an organ such as a kidney or heart from one individual to another.
U
U.S. Food and Drug Administration (FDA) - Government agency that
regulates all medical devices and drugs.
V
Vagus Nerve - The tenth cranial nerve, which is a mixed nerve
that has both motor and sensory function.
Ventricle - Chambers within the brain that contain the cerebrospinal
fluid.
Vertebra - One of the 33 bones of the spinal column. A cervical,
thoracic, or lumbar vertebra has a cylindrically-shaped bony anteriorly
and a neural arch posteriorly (composed primarily of the laminae
and pedicles as well as the other structures in the posterior aspect
of the vertebra) that protects the spinal cord. The plural of vertebra
is vertebrae.
W
Wire - Metal thread available in various diameters and various
degrees of stiffness and is generally used in surgery to transfix
fractured bone.
X
Xenograft - A graft derived from one species for use in another
species.
Y
Z
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John
J. Regan, M.D.