Implants exam review

The ________ is legislation which was designed so that the FDA could quickly be informed of any medical product that has caused or suspected to have caused a serious illness, injury or death.

SMDA Federal

________ stands for the Center for devices and radiologic health

CDRH

micro movement

If ________ occurs then contacting bone tissue is replaced with fibrous tissue, loosening the screw.

Wires

________- used for reattaching large fragments;

________ 3D represents an innovative approach to the requirement for durable support for the arterial lumen after intervention.

Biomimics

________ are internal struts to stabilize long bone fractures.

IMs

________ is Low Vacuum Melted to achieve high levels of purity, reduced inclusions, and reduced delta ferrite particles.

316LVM

________ Insoluble proteins Resilience Long range deformability Elasticity Chemically inert and resistance to dissolution Hydrophobicity Stability Large strains with small applied stress Complete return to original dimensions Small hysteresis (small energy dissipation) Collagen Enables flexible deformation Provides high mechanical strength to tissues like tendons Proteoglycans Attract and trap water like gel Hydrates and lubricates tissues resists /absorbs repetitive mechanical loading such as in cartilage.

Elastin fibers

First use for a vascular stent came from ________ in 1966 when they described a Prosthetic- stented aortic homograft used for mitral valve replacement.

Weldon et al

________ 9000 is Maintained by ________ (International Organization for Standardization) and is administered by accreditation and certification bodies Is a qualifier for international markets or specific domestic customers Certification can be a valuable marketing tool

ISO

HB

________ is for cancellous bone.

________ is hard to repair, so damaged joints lead to long term problems with no natural solution.

Cartilage

Screw ________ varies with time: depends on growth of bone into screw threads.

pullout strength

________ is also sometimes referred to as "cGMP.

GMP

________ and structures that are inserted directly into the body of the patient Differ from prostheses in that the prostheses are commonly attached to the body rather than being an implant The biomedical implants are most commonly a product developed from studies in the BME field.

Medical devices

The ________ is considerably more complex than the 510 (k) process.

PMA process

The ________ is not available via the Freedom of Information process.

PMA submission itself

________ are permanent implants, an extensive amount of bone and cartilage is removed during the procedure.

Joint replacements

The ________ is designed not only to promote swirling blood flow but also to accommodate the complex biomechanical challenge associated with stenting this anatomically mobile artery Nonplanar curvature in arterial systems promotes swirling flow which Increases shear wall stress which is not only atheroprotective but protective against neointimal hyperplasia following intervention.

helical line stent

CFR code for Orthopedic medical devices is ___ CFR code for Cardiovascular devices is _.

888 870

________ regulates both the device development and the manufacturing process for all class 2 and 3 devices from the start of development phase until the device is no longer supported by the manufacturer Also covers the manufacturing process for many class 1 devices It does not cover the research process for any medical devices.

QSR

The goal of the ________ is to create a self- correcting system that reliably produces robust device designs and production methods, ensuring that devices perform in a manner consistent with their intended use.

QSR

________ are similar to rubber bands and can be stretched very far, store energy, and release most of the elastic energy when bouncing back important to dynamic tissues such as lung alveoli Elastic fibers are 10- 12 nm in diameter Amorphous elastin forms the core Microfibrillar components surround the core Fibers tend to branch Fibers aggregate to form network structures Ropes (ligaments) Concentric sheets (blood vessels) Honeycombs (elastic cartilage)

Elastins

___fixation to reduce foreign body reactions (.625 %)

glutaraldehyde

A(n) ________ may be used to keep fractured bones stabilized and in alignment.

external fixation device

There is a(n) ________ shapes to increase area of contact with the internal cortex of the bone.

variety of IM

________ shield underlying bone from stress needed for healthy growth, high contact flat plates inhibit vascularization of the outer bone.

Rigid plates

________: large threads to increase thread to bone contact, can also have different thread types.

Cancellous Screw

________ periprosthetic fracture varies between .0- 4 % depending on the patient risk factor and implants used Intraoperative fractures during total knee replacement leads to increased operative time, higher complications rates and poor functional outcomes Studies have shown that the fracture risk is higher in female patients, rheumatoid patients, and patients with severe knee deformity.

Incidence of Intraoperative

More than 3000 medical devices are cleared on to the U.S. market every year through the ___

510 (k) premarket notification process

what are the first two stages of host reactions for stent implants

**Initiates thrombus formation, Inflammation**

what are the four major Systemic antiplatelet drugs

Aspirin, ticlopidine, clopidogrel, heparin

what are the 1st and second type of collagen

1. skin, tendons, bone
2. cartilage

what organization is in charge of the following Organization and Personnel, Buildings and Facilities, Equipment, Production/Packaging Controls, Documentation, Storage and Distribution, Quality and Laboratory Controls

GMP

Two tip types for pins

trochar (for cortical bone), diamond end

size of pilot drill-hole, depth of screw, outside diameter of screw, and bone quality affects what

Holding power

Screw pullout strength varies with time and depends on

growth of bone into screw threads

large threads to increase thread to bone contact, can also have different thread types

Cancellous Screw

lack of annoying light reflection during surgery; Creates a uniform surface layer of compressive stress, which acts to combat stress cracks and corrosion, therefore, increasing the life of implant; Greater ultrasound reflection; Cleaner part, free from residues with a low CFU (microorganism) count, resulting in easier autoclave sterilization

We Satin Finish our plates giving the following advantages

External fixation is usually used when internal fixation is contraindicated

often to treat open fractures, or as a temporary solution

What makes something a biomedical implant

medical devices and structures that are inserted directly into the body of the patients

how does a biomed implant differ from prostheses

prostheses are often attached to the body instead of in the body

What are the 5 material considerations for biomedical implants/devices?

* Safety
* Durability
* Mechanical compatibility
* Biodegradability 
* Biofunction 

How PMMA was adopted as an implantation material; who was the inventor?

* WW2 pilots would get PMMA in their eyes and no adverse effects were noted, invented by Dr. Harold Ridley 

List three uses of PMMA as biomedical implants/devices.

* Intraocular lenses 
* PMMA bone cement is orthopedic surgery 
* Dentures

What is intraocular lens and what disease they treat?

An intraocular lens is a tiny artificial lens for the eye, it works by replacing the eyes natural lens that is removed during cataract surgery

Differences between balloon expandable stents and self-expandable stents;

balloon expandable stents use a balloon to inflate the diseased area then the artificial valve is deployed

self expanding stents are produced at the desired final diameter once it has reached the target area it expands

how are balloon expandable stents and self expandable stents inserted into the body

balloon expandable stents are guided to the target area by a catheter

self expandable stents are spring loaded into a much smaller catheter

what are the materials used by balloon expandable stents

balloon expandable stents are often made of 316 stainless steel or other non corrosive, stiff alloy metals like tantalum, or Cr-Co super alloys, Elgiloy (Co-Cr-Ni alloy), MP35N (Nickel-cobalt base alloy), and L605 (cobalt-chromium-tungsten-nickel alloy) 

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what are the materials used by self expanding stents

Nitrol a nickel titanium allow with shape memory capability

What are the last two stages of host reactions for stent implants

* **Proliferation of vascular smooth muscle cells in the media and neointima** 
* **Remodeling**

What was going on with Abbott’s Absorb bioresorbable vascular stent?

high rates of blood clots caused them to discontinue it in 2017

list some key parameters in stent design

* Biocompatibility 
* High expansion ratio (deployed diameter/ crimped diameter)
* A high degree of radial strength 
* Sufficiently radiopaque

What system is used for stent and tube cutting; working principle?

The **Sigma stent and tube cutting system** is used for stent and tube cutting. This is done by first designing the stent using CAD and then the cutting system will laser cut the stent from a protruding piece of metal with a stream of water cooling as necessary

the first host reaction for stent implants is caused by

 the exposure of the **Subendothelium** and the stent material to the blood stream

what is **In Stent Restenosis**

The **Growth of tissue into the stented region**

what percent of clinical failure of stenting procedures is caused by The **Growth of tissue into the stented region**

20-30%

what percent of restenosis is caused by stent design

20-50%

**biomimics 3D has created a Nonplanar curvature in arterial systems promotes swirling flow** which

increases shear wall stress

what are two drug eluting stents

**Paclitaxel drug eluting coated stents for coronary artery placement**

**Paclitaxel drug eluting stents for Femoropopliteal Artery placement**

what are the 3 major components of the ECM

structural proteins (collagen), Glycosaminoglycans , proteoglycans

what is the ECM

**the ECM is any material part of a tissue that is not part of any cell**

what is the primary structure of collagen

the sequence of amino acids that make up each of the polypeptide chains

what is the second structure of collagen

the repeating pattern of amino acids that leads to the formation of a tight triple helix structure

what is the tertiary structure of collagen

Three chains packed together into a chemically stable structure unit: homotrimer and heterotrimer

what is the quaternary structure of collagen

the assembly of multiple collagen molecules into larger fibrils which can be arranged into sheets or bundles

how much of the total proteins in the body does collagen account for

1/3

what percentage of the skin does collagen account for

40

what are the last two types of collagens

blood vessels and bladder

all basal laminas

fibronectin is what kind of protein

adhesive

the reinforcement of concentric layers in the osteon does what

they are reinforced by collagen fibers arranged in a specific orientation to resist bending and torsion forces.

what are the concentric layers of bone tissue called

lamellae

___ are similar to rubber bands and can be stretched very far, store energy, and release most of the elastic energy when bouncing back important to dynamic tissues such as lung alveoli

elastin

elastic fibers are ___ in diameter

10-12 nm

what is the structure of elastin?

* **Amorphous elastin forms the core**
* **Microfibrillar components surround the core**

elastin Fibers aggregate to form what network structures

* **Ropes (ligaments)**
* **Concentric sheets (blood vessels)**
* **Honeycombs (elastic cartilage)**

what is the structure of small PGs

composed of core proteins that determine the specific properties and functions of the PG

GAG chains determine the PGs ability to bind to water and regulate tissue hydration

what is the function of small PGs

* Regulating cell signaling and behavior
* Modulating the biomechanical properties of tissues
* Supporting tissue hydration and lubrication
* Maintaining the structural integrity of tissues

what is the function of large PGs

* **Lubricants (absorb water)**
* **Shock absorbers (resist compression)**
* **Space filters**
* **Regulate diffusion and flow of both water and macromolecules**

what does aggrecan do

* Predominant proteoglycan in cartilage 
* Forms large aggregates >4 um long, bigger than bacteria 
* Give cartilage unique gel-like properties, trap and attract water

what is the central component of aggrecan

Hyaluronan (HA)

Biomechanical properties of collagen

* Enables flexible deformation 
* Provides high mechanical strength to tissues like tendons

PGs resist/absorb ___ such as in cartilage

repetitive mechanical loading

Give examples of blood interfacing implants

* **Heart valve prosthesis** 
* **Total artificial heart**
* **Ventricular assist devices**
* **Vascular prosthesis**

 What are the material requirements for long-term implants?

\n

* Biocompatibility, nontoxicity, and durability 
* Non-irritating to tissue, resistant to platelet and thrombosis deposition 
* Non-degradable in the physiological environment 
* Neither absorb blood constituents, nor release foreign substances 
* Mimic the function of the organ
* Suitable size and weight
* Easily available, inexpensive, machinable, sterilizable, and long storage life

what are the four chambers of the heart

* Pulmonary heart valve 
* Aortic valve
* Tricuspid valve
* **Mitral valve**

which heart valve only has two leaflets

mitral valve

what is stenosis

*  **impeded forward flow and/or backward flow**

When the valves in the heart do not close completely leading to a leaky valve where blood can flow backwards when it should flow forwards and vise versa this is called what?

heart valve regurgitation

what are the 3 major types of heart valve replacements

mechanical heart valves, bioprosthetic heart valves, transcatheter heart valves

what are the 3 types of MHVs

*  **caged-ball, tilting disk, Bi-leaflet valve**

what is a drawback of MHVs

cavitation

what are the two types of bioprosthetic heart valves

**Homograft implant from deceased patient**

**Xenograft from animal models**

how do caged ball valves work

when the blood pressure is higher inside the chamber of the heart than the outside the ball is pushed up and allows blood flow and vise versa

**when was the Production of starr-edwards valve discontinued**

**2007**

how do tilting disk valves work

two metal supports open the disk when blood is pushed through the valve and it closes in between heart beats

how does a bi-leaflet heart valve work

* two semicircular leaflets that rotate about struts attached to the valve housing 

* A rapid formation of vaporous microbubbles in the fluid due to the drop of pressure, bubbles will collapse or implode during recovery
* Cause pressure or thermal shockwaves and fluid microjets
* this is called what

cavitation

what are two kinds of bioprosthetic heart valve replacements

bovine pericardium

porcine aortic valve

bovine pericardium are less ___ compared to porcine bioprosthesis due to pericardial design and increased orifice area

stenotic