Sterilisation

Question 1

Define “Sterile”

Answer 1

Absence of all living organisms

Question 2

What is SAL?

Answer 2

Sterility Assurance Level
Probability that a given implant will remain non-sterile during a sterilisation process (minimum SAL = 1x10-6. E.g. 1 in a million)

Question 3

What is Autoclaving?

Answer 3

Expose implant to saturated steam at 121 degrees Celsius with pressure applied.

Question 4

Benefits of Autoclaving

Answer 4

Good for metals
Speed
Simplicity
Lack of toxic residue

Question 5

Disadvantages of Autoclaving

Answer 5

High temp
High pressure
Limited implants and packaging can be used

Question 6

How is Ethylene Oxide used?

Answer 6

Commercially, implants in gas permeable packing are loaded into a sterilisation chamber
Steriliser maintained at 30-50 deg C until SAL is attained
Chamber evacuated to remove EtO and several purge cycles are run

Question 7

Problems with EtO

Answer 7

Residual EtO are a concern due to toxicity

Question 8

Advantages of EtO

Answer 8

High Penetration

Compatibility with wide range of materials

Question 9

Advantages of gamma radiation

Answer 9

Simplicity
Rapid and effective
Can be measured

Question 10

Disadvantages of gamma radiation

Answer 10

Capital expense
Material incompatibility
Source half life
Danger

Question 11

Applications for e-beam radiation

Answer 11

Sterilisation of small, thin products immediately following packaging