Medical Apparatus: Imaging Guide to Orthopedic Devices

Glossary: N - Q



Terms: Click below for the desired term







Medical Devices, Medical Procedures, and Foreign Bodies:
Abbreviations, Acronyms, and Definitions

by Tim B Hunter, MD, MSc and Mihra S. Taljanovic, MD, PhD



NAC. Nonattenuation-corrected FDG PET.

NAD.  No active disease, or no acute disease. 

Nanogel (Teknimed)
. A hydroxyapatite nanoparticle gel used as a bone substitute. A product of Teknimed it may be injected percutaneously into a bone defect.

nanodevice. Any tiny device based on nanotechnology which involves research and development at the atomic, molecular, or macromolecular levels in the length scale of approximately 1 - 100 nanometers (nm).

Napier.  A type of pessary.

NASPGHAN. North American Society for Pediatric Gastroenterology, Hepatology & Nutrition.

Nasogastric tube.  A generic term for any rubber or plastic tube used for decompression of the stomach.

Natta stereospecific polymerization technique. Guilo Natta (1903-1979), an Italian chemist, won the Nobel Prize in Chemistry in 1963 with Karl Ziegler for work on polymers. Their classes of catalysts are now known as Ziegler-Natta catalysts.

NB.  nota bene; Latin for “note well.”

NCBI. National Center for Biotechnology Information.

NCI. National Cancer Institute.

NCL. Nanotechnology Characterization Laboratory of the National Cancer Institute (NCI).

NCPC. National Capital Poison Center.

NCRP. National Council on Radiation Protection and Measurement.

NCTR. National Center for Toxicological Research.

NDT.  Nondestructive testing.  

neck brace. See cervical collar

needle gauge.  See gauge.

NEEP. Negative end-expiratory pressure.

Neer  prosthesis. A type of shoulder prosthesis.

NEFT.  Nasoenteric feeding tube.

Neibauer prosthesis.  A type of prosthesis used in the joints of the hand.

NEMA.  National Electrical Manufacturers Association.

nephrostomy tube.  A tube placed into the pelvis of the kidney for the external drainage  of urine.

Neufeld nail.  A device designed for internal fixation of intertrochanteric femur fractures.

NeuFlex MCP/PIP Finger Joint Implant System. A product of DePuy Synthes for finger joint implant replacement in patients with severe rheumatoid arthritis.

Neutralization plate.  An orthopedic fixation plate used with interfragmentary (lag) screws to protect the screw fixation by neutralizing various mechanical stresses at the fracture site. Neutralization plates are typically used in the shaft of long bones. They stabilize the bone fragments but do not compress the bones together, unlike dynamic compression plates.

Nexel (total elbow prosthesis). A semiconstrained elbow prosthesis for treatment of advanced elbow rheumatoid arthritis, degenerative osteoarthritis, or elbow reconstruction after severe trauma. It was designed after the earlier Coonrad-Morrey total elbow prosthesis.

NG tube.  Nasogastric tube.

NIH.  National Institutes of Health

NHSN. National Healthcare Safety Network (CDC).

Nissen fundoplication.  A surgical procedure to prevent gastroesophageal reflux.

Nissenkorn prosthesis.  An endourethral prosthesis used to relieve urinary retention in high-risk surgical patients.

nitinol.  Same as nickel titanium, an alloy of nickel and titanium. 

nitinol filter.  A type of inferior vena cava filter used to prevent clot propagation to the lungs. Also called Simon Nitinol filter.

NLM. National Library of Medicine.

NMR.  Nuclear magnetic resonance. A synonym for magnetic resonance. The name NMR imaging was changed to magnetic resonance imaging in part because the term nuclear has an unpleasant connotation in some circles.

NOMS.  Not on my shift. It has a connotation similar to that of NIMBY (not in my backyard).

nonself-tapping screw. See tap and self-tapping screw.

Norian SRS Cement.  A bone graft substitute that is a registered trademark of Kensey Nash Corporation (Exton, PA). It was initially developed for stabilization of distal radial fractures, and it consists of a moldable cement that hardens in vivo, forming a carbonated apatite crystalline material that is later reabsorbed.

Norport-AC, -DL, -LS, -PT, -SP.  Types of vascular access ports.

NovaBone. A registered trademark of NovaBone Products, LLC, NovaBone is a phosphorus calcium silicate composite used as a bone substitute to fill bony defects and stimulate new bone formation. Formulations of it are used in both orthopedic and dental applications.

Novacor.  A type of ventricular assist device.

Nova T IUD.  A type of intrauterine contraceptive device.

NWPT. Negative wound pressure therapy system. A system in which a specialized dressing is placed over a wound, such as a diabetic foot ulcer. The dressing is attached to a tube that is sealed around the wound and is connected to a machine that applies negative pressure (vacuum suction) at the wound.

nylon.  The first commercial polymer, made in the 1930s. Nylon is now also a generic term for a family of polyamide polymers. These polymers are used to make fibers, fabrics, and extruded forms.


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OD.  Outside diameter, overdose, or right eye (oculus  dexter).

OKA.  Otherwise known as.  Same as AKA (also known as).

olecranon plate. A special type of periarticular locking plate configured to fit on the proximal humerus for treatment of comminuted fractures involving the olecranon and coronoid. They are sometimes used with olecranon osteotomies. These plates are precontoured for anatomic fit. The proximal spoon shapted portion of the plate is slightly thinner than the shaft portion.

oleo plombage.  See wax plombage.

OLIF. Oblique lumbar interbody fusion (also known as anterior to psoas approach {ATP}), a surgical approach between the retroperitoneum and psoas muscle to a lumbar disk.

olive wire. A type of fixation wire with a bulge or "olive" shape at the end of the wire. Olive wires are used with external fixators, and the olive portion of the wire is external to the skin. Tension can be applied to the ball portion of the wire to pull fracture fragments into alignment.

Omnicarbon valve.  A type of prosthetic heart valve.

OmniPhase.  A type of penile prosthesis.

Omniscience valve.  A type of prosthetic heart valve.

one-third tubular plate.  A fracture fixation plate with a circular profile. A one-third tubular plate represents one-third of a cylindrical circumference. Tubular plates are thin, self-compressing, and easily bent to adapt to varying fracture conditions.

OOP.   Out of plaster. It should not be confused with oops.

OPO. Organ procurement organization.

OPTN. Organ Procurement and Transportation Network.

ORA. Office of Regulatory Affairs (FDA). The FDA Office responsible for FDA inspections to health and veterinary manufacturer facilities, inspections of health and veterinary manufactured products, and control of health and veterinary imported products.

OREF.  Open reduction and external fixation.

ORIF.  Open reduction and internal fixation.

Orion plate.  A type of anterior cervical spine fusion plate.

orogastric tube.  Any tube going into the stomach through the mouth rather  than through the nose (a nasogastric  tube).

orotracheal tube.  A tube inserted in the mouth to keep the mouth open and the teeth from biting the tongue.

orthodontic appliance. A device (braces) to help teeth grow straight.

OrthoGlide (Orthoglide) medial knee system. A cobalt-chrome self centering tibial hemiarthroplasty used in the treatment of isolated medial compartment osteoarthritis of the knee.

orthosis. A generic term for an external orthopedic appliance to align, stabilize, support, correct or improve function of movable parts of the body, such as the spine or the limbs. Braces and splints are common orthotics. A dental orthotic often refers to a dental plate or similar oral device.

orthotic. Similar to orthosis.

ORTHOSPHERE. A spherical ceramic interposition arthroplasty for use in the small joints of the foot.

OS.  Operating system.  Left eye (oculus sinister).

OSHA.  Occupational Safety and Health Administration.  See

osseointegration.  Chemical bonding between living bone and an implant.

OSTEOSET Bone Graft Substitute.  A registered trademark of Wright Medical Technology, Inc. (Arlington, TN), a bone graft substitute composed of calcium sulfate.

OTC.  Over the counter. It is used in reference to drugs and medical equipment that may be bought without a prescription.

OTW.  Off-the-wall; a phrase used to mean unexpected, bizarre.

OVCF. Osteoporotic vertebral compression fracture.

OWHTO. Open(ing) wedge high tibial osteotomy, a form of proximal tibial osteotomy used in the treatment of medial compartment knee arthritis.

Oxinium. Oxidized zirconium ceramic used for total joint arthroplasty surfaces. Oxygen is absorbed into zirconium metal transforming the surface into a ceramic with the rest of the metal remaining unchanged to provide a supportive backing to the ceramic surface.


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P& V.  Pyloroplasty and vagotomy.

PAC.  Pulmonary artery catheter. See also Swan-Ganz catheter. Also may mean premature atrial contraction.

PACS.  Picture archiving and communications system.  A descriptive term for the software system used to store, retrieve, and display digital images.

Palmaz endovascular stent.  A type of stainless steel vascular stent used to maintain the lumen in narrowed vessels and ducts.  It is now also used in other applications such as portacaval shunts.

Pantopaque.  An oil-based myelographic contrast agent. It is not miscible with water and is no longer used, having been replaced by low-osmolar water-soluble agents. It is very slowly absorbed and remains radiographically visible for years.

paramagnetic. A term referring to any material attracted to an externally applied magnetic field. Most chemical elements are paramagnetic.

particle disease. The build-up of tiny particulate debris in soft tissues, most often from gradual wear and tear with shedding of particles, usually polyethylene, in joint prostheses. This condition can lead to osteolysis, granulation tissue formation, and prosthesis failure. A somewhat related condition is metallosis which is caused by shedding of tiny metallic particles leading to bone destruction and inflammatory tissue formation with eventual joint prosthesis failure.

Particle reinforcement.  A technique used to improve the properties of bone cement.  For example, inclusion of bone particles in PMMA cement somewhat  improves its stiffness and considerably improves its fatigue life.

PC-Fix. Point contact fixator, a narrow plate implant with small points on its undersurface. These come into contact with the bone. Small self-tapping screws are used with the screw head firmly locking into the plate hole with a small thread. The screws are monocortical. The PC-Fix is a forerunner of the less invasive stabilization system (LISS) and the locking compression plate (LCP) and is generally used in forearm bones.

PCP. President's Cancer Panel.

PDK. Polydiketoenamine, an enlessly recyclable polymer.

PDMP. Prescription drug monitoring program.

PDQ.  Pretty darn (damn) quick; similar in meaning to ASAP (as soon as possible).

PDS. Posterior dynamic stabilization device or surgery. A PDS device couples transpedicular screws with a flexible longitudinal connecting system, in contrast to the rigid rods used for conventional posterior spinal fusion.

PEEK. Poly ether ether ketone (or polyethylene ketone), a colorless organic polymer sometimes used in medical implants.

Peel-Away (introducer, sheath).  A registered trade name of Cook Medical, Inc (Bloomington, IN), often used generically for any type of introducing catheter or sheath that aids in the placement of an indwelling catheter or tube.  Near the end of the procedure, the introducer is peeled off the permanent catheter and discarded.

PEEP.  Positive end-expiratory pressure.

PEG. Polyethylene glycol, a polymer of ethylene dioxide.

PEG tube.  A gastrostomy tube placed by means of percutaneous endoscopic technique.

PEMF. Pulsed electromagnetic field. A pulsed low-level electromagnetic field is used as part of bone growth therapy to stimulate bony healing after spinal surgery or to treat delayed fracture healing.

Penrose drain.  A traditional type of gravity drain.  It is also convenient for use as a tourniquet. Penrose drains are often made from soft latex rubber to lessen wound irritation.

Periarticular locking plate. A plate and screws fixation construct for use in highly comminuted fractures and/or where deficient bone stock or poor bone quality is encountered. There are locking screw holes combined with the compression plate allowing the plate to be used as both a locking device and a fracture compression device.  Periarticular locking plates may also have varying thickness, greater in the diaphysis and thinner in the metaphysis.

PerioGlas. A registered trademark of NovaBone Products, LLC, PerioGlas is a dental bone grafting material.

peritoneal jugular (LeVeen) shunt. A shunt designed to drain fluid from the peritoneal cavity to the central venous system.

pessary.  A simple mechanical device inserted in the vagina for the treatment of vaginal and uterine prolapse.

PET scan. Positron emission tomography, a nuclear medicine imaging study which is frequently used along with a CT scan. PET scanning often uses a radioactive isotope of fluorine F-18 in combination with other substances: F18-FDG (F-18 Fluorodeoxyglucose); F18-NaF (F-18 Sodium Fluoride).

PHE. Public health emergency.

PHI. Personal health information.

PHM. Population health management.

PHP. Proximal humeral (fixation) plate.

Philadelphia collar.  A type of cervical immobilization collar molded from plastic. It has chin and occipital supports.

PIC, PICC, PPC.  Peripherally inserted (central) catheter. These small catheters are peripherally inserted near the antecubital fossa with the tip usually in the superior vena cava.

pigtail.  Term used to describe the appearance of the end of a drainage catheter or angiography catheter with a curvature similar to that of a pig’s tail.

Ping-Pong ball plombage.  A type of chest treatment used for tuberculosis in the era before antibiotics.

pins in plaster. The combination of percutaneous fracture fixation pins, such as K-wires, with a plaster cast for treatment of an extremity fracture.

PISF. Posterior interspinal fusion.

pitch. The distance between screw threads.

PJI. Prosthetic joint infection.

plastic. A synthetic material made from an organic polymer that can be easily molded into a shape while soft and then hardened into a rigid form. Common trademark plastics are Bakelite, Nylon, and Lucite.

plasticizer. Any substance added to plastics to make them soft or pliable.

Platinum metals.  Platinum, ruthenium, rhodium, palladium, osmium, and iridium. These expensive metals are sometimes used in alloys for surgical implants.

PLDLLA. Poly (L-lactide-co-D, L-lactide), a radiolucent resorbable biopolymer implant material most frequently used in prosthetic vertebral cages.

PLF. Posterolateral lumbar fusion.

PLIF. Posterior lumbar interbody fusion, a type of lumbar spine operative fusion.

PM or PPM.  Pacemaker.

PMMA.  See  poly(methyl  methacrylate).

PND.  Percutaneous needle drainage.

PO.  per orem; Latin for “by mouth.”

polycarbons (polycarbonates).  High strength polymeric thermoplastic materials that match the properties of light metals. They have a resistance to most chemicals and to water over wide temperature ranges.

Polyester (fiber).  Long-chain polymeric compound produced by the combination of an ester of a dihydric alcohol (usually ethylene glycol) and terephthalic acid. Dacron was the first commercial polyester fiber, and the terms Dacron and polyester are often used interchangeably. A polyester fiber is strictly defined as a synthetic fiber containing at least 80% polyester compounds.

polyethylene (PE).  A simple polymer made from ethylene (CH2=CH2).

polymer.  (poly = “many”;  mer = “part”) molecules linked together  in long chains by the primary covalent bonding  in the main back bone chain with C, N, O, Si, and so forth, as side atoms.

poly(methyl methacrylate), PMMA.  An acrylic polymer used in a variety of prostheses often as a cement. Poly- methylmethacrylate or methacrylate are the terms most commonly used to describe PMMA, though they are less chemically correct.

polytetrafluoroethylene (PTFE), polytef.  Chemical name for Teflon and Gore-Tex.

POOH.  Postoperative open-heart surgery.

POP.  Plaster of Paris, progesterone only pill.

porcelain. A white, dense, translucent ceramic produced by high temperature fusion of feldspar, kaolin, quartz, and other substances. There are many types of porcelain which vary depending on their ingredients and fusion temperatures. Dental porcelain is glass-like and somewhat transparent.

porcelain veneer crown.  A porcelain tooth cap.

porcine graft (valve). A biologic body part derived from a pig.

POROCOAT Porous Coating. A product of DePuy Synthes used in hip reconstruction. It was introduced in 1977 and is composed of titanium sintered metal beads allowing live bone to affix into the porous coating.

Port-A-Cath.  A type of vascular access port.  This term is a trademark of Smiths Medical (UK), but it has come to be used generically for any type of vascular access port with a subcutaneous reservoir for injection of medication.

Portacath.  A corrupted spelling of Port-A- Cath.

Portnoy shunt.  A type of ventriculoperitoneal shunt.

posterior cervical plates.  A system of plates and screws placed posteriorly for fixation of unstable  spine fractures  and dislocations or to stabilize the spine after surgery.

posterior spinal instrumentation (fixation).  A generic term used for a wide variety of wires, rods, plates, and screws designed for thoracic  or lumbar  spine stabilization after surgery to correct severe traumatic, congenital, or developmental spinal abnormalities. There  are many different posterior spinal instrumentation designs, some of the more common being Luque and Hartshill rectangles;  Harrington and Knodt  rods; and Steffee, Edwards, Roy Camille,  Texas Scottish Rite Hospital (TSRH), and Cotrell- Dubousset pedicle fixation systems.

Posterior wiring.  A method of providing spinal fixation with posteriorly placed stabilizing wires or plates. Luque and Hartshill rectangles are types of spinal fixation plates sometimes used with sublaminar wires.

PP.  Percutaneous pinning, percutaneous pin.

PPE.  Personal protective equipment, such as gloves, mask, and gown, used for handling dangerous chemicals, blood products, and bodily fluids.

PPM.  Permanent pacemaker.

PR.  per rectum; Latin for “via the rectum.”

PRN.  pro re nata; Latin for “as necessary.” 

Pro-Dense. A bone graft substitute product of Wright Medical Technology, Inc., consisting of a mixture of 75% calcium sulfate and 25% calcium phosphate. It is a paste that can be injected or packed into open bone voids or gaps not intrinsic to the stability of the bone structure. It is intended to be resorbed and replaced with natural bone during the healing process.

ProDisc-C (DePuy Synthes). A cervical spine total disk replacement (TDR) for treatment of a single degenerated disk in the upper cervical spine (C3-7). It has a ball and socket design in which a plastic inlay is affixed to the bottom metal endplate forming the ball, and a concave metal surface in the top endplate forms the socket.

ProDisc-L (DePuy Synthes) is for total disk replacement (TDR) for the lumbar spine (L3-S1).

progestasert.  A type of intrauterine contraceptive device.

PROSTALAC. Prosthesis of antibiotic-loaded acrylic cement.

PRP. Platelet rich plasma.

prosthesis.  Artificial substitute for a missing body part. Sometimes the terms prosthesis, implant, and medical device are used interchangeably.

PSC.  Percutaneous suprapubic cystostomy.

PSF (PSIF).  Posterior spinal fusion or posterior spinal instrumentation and fusion.

PTBD (PTHBD).  Percutaneous transhepatic biliary drain.

PTFE. polytetrafluoroethylene, the parent compound for Gore-Tex and Teflon.

Puddu plate. A fixation plate most commonly designed for open wedge high tibial osteotomy (OWHTO) used to treat medial compartment knee arthritis. The plate is placed along the medial aspect of the proximal tibia to stabilize the medial osteotomy and possible bone graft. It may be modified for other osteotomies close to the knee in either the femur or the tibia.

Pudenz-Shultz ventricular access catheter.  A type of ventriculoperitoneal shunt.

PVR.  Pulmonary valve replacement, peripheral vascular resistance.

PVP. Percutaneous vertebroplasty.

pyrocarbon (pyrolitic graphite). A material similar to graphite but with a degree of covalent bonding between graphene sheets in the material. It is not found in nature. It has a single cleavage plane similar to mica. Pyrocarbon has many medical applications, because blood clots do not easily form on it. It is used in artificial heart valves and as a coating on orthopedic implants. PyroCarbon is a trademark of Biomet Manufacturing.

PZT. Lead zirconium titanate, a crystal piezoelectric material found in ultrasound transducers.


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QED.  quod erat demonstrandum; Latin for “that which was to have been shown.”

QMS. Quality management systems.

QoL. Quality of life.

Q-Port.  A type of vascular access port.

QsReg. The FDA Quality System (QS) Regulation/Medical Device Good Manufacturing Practices system for medical devices.

QWERTY.  Arrangement of the letters on the left half top row of typewriters and typical computer keyboards.  This arrangement of letters was placed on early typewriters to slow the typist in order to prevent jamming of the typewriter.  It is not the most efficient arrangement of keys for rapid typing, but it has been widely accepted for over 100 years. It is standard on almost all computer keyboards.

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Author contact information

Tim Hunter

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