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Hello, everyone.... I have a question concerning differentiating hazards from root causes and/or hazardous situations… It seems like such a simple concept, but I find myself being incredibly indecisive about it.
I guess what I am having a hard time understanding is deciding on what level the hazards should be defined at. For instance I have a very simple example that for some reason I cannot wrap my mind around: if a nitinol guide wire, which is to pass through an implant to make sure it is centered properly (user need), has a design input of “Guide wire outer diameter to be .XXX” +/- .XXX,” then what would the hazards be only in relation to failure/fracture? The following are a few approaches I have come up with in my attempt to pretty much just say “the thing can break, and breaking is bad”:
“Mid-Level”
(1)
Hazard: Fracture
Events Leading to Hazard: Inadequate strength, Excessive (user input) energy, inadequate material properties, poor design control, etc.
Hazardous Situation: Contamination of operative site with foreign debris, deterioration or loss of device function (unguided implant placement), increased intraoperative time, etc
Harm: Tissue damage, revision surgery, etc
OR
“Low-Level”
(2)(a)
Hazard: Inadequate device strength
Events Leading to Hazard: Incorrect material due to insufficient design specifications, Inadequate inner diameter size due to uncontrolled manufacturing process, etc
Hazardous Situation: deterioration or loss of device function (unguided implant placement), fracture, contamination of operative site with foreign debris, etc
Harm: Tissue damage, revision surgery, etc
And
(2)(b)
Hazard: Excessive (user input) energy
Events Leading to Hazard: Inadequate factor of safety, untrained physician, etc
Hazardous Situation: deterioration or loss of device function (unguided implant placement), fracture, contamination of operative site with foreign debris, etc
Harm: Tissue damage, revision surgery, etc
And
(2)(c)
Hazard: Inadequate material properties
Events Leading to Hazard: uncontrolled process, new material selection, insufficient design control, etc
Hazardous Situation: deterioration or loss of device function (unguided implant placement), fracture, contamination of operative site with foreign debris, etc
Harm: Tissue damage, revision surgery, etc
OR
“High-Level”
(3)(a)
Hazard: Contamination of operative site with foreign debris
Events Leading to Hazard: fracture caused by incorrect material choice, fracture caused by inadequate inner diameter size, etc
Hazardous Situation: increased intraoperative time, increased friction in joint, adverse tissue reaction, etc
Harm: tissue damage, revision surgery, infection, etc
And
(3)(b)
Hazard: loss/deterioration of function: implants are unguided
Events Leading to Hazard: fracture caused by incorrect material choice, fracture caused by inadequate inner diameter size, etc
Hazardous Situation: increased intraoperative time, increased joint stresses, etc
Harm: tissue damage, revision surgery, infection, etc
---
I could go on, and that is just for the hazard relating to the device failing/fracturing…. I believe another hazard exists that relates to the interface mating condition between the guide wire and the implant, and I have the same problem with that as I do with what you just read above (is “insufficient mating clearance with implant” the hazard, or is “oversized outer diameter” the hazard, or is “unguided implant” the hazard, etc?)
Thanks for any advice you can offer, and sorry for the long point – I am just so far past the point of over-thinking this whole hazards-thing that I am at a complete loss haha.
Take care,
K
I guess what I am having a hard time understanding is deciding on what level the hazards should be defined at. For instance I have a very simple example that for some reason I cannot wrap my mind around: if a nitinol guide wire, which is to pass through an implant to make sure it is centered properly (user need), has a design input of “Guide wire outer diameter to be .XXX” +/- .XXX,” then what would the hazards be only in relation to failure/fracture? The following are a few approaches I have come up with in my attempt to pretty much just say “the thing can break, and breaking is bad”:
“Mid-Level”
(1)
Hazard: Fracture
Events Leading to Hazard: Inadequate strength, Excessive (user input) energy, inadequate material properties, poor design control, etc.
Hazardous Situation: Contamination of operative site with foreign debris, deterioration or loss of device function (unguided implant placement), increased intraoperative time, etc
Harm: Tissue damage, revision surgery, etc
OR
“Low-Level”
(2)(a)
Hazard: Inadequate device strength
Events Leading to Hazard: Incorrect material due to insufficient design specifications, Inadequate inner diameter size due to uncontrolled manufacturing process, etc
Hazardous Situation: deterioration or loss of device function (unguided implant placement), fracture, contamination of operative site with foreign debris, etc
Harm: Tissue damage, revision surgery, etc
And
(2)(b)
Hazard: Excessive (user input) energy
Events Leading to Hazard: Inadequate factor of safety, untrained physician, etc
Hazardous Situation: deterioration or loss of device function (unguided implant placement), fracture, contamination of operative site with foreign debris, etc
Harm: Tissue damage, revision surgery, etc
And
(2)(c)
Hazard: Inadequate material properties
Events Leading to Hazard: uncontrolled process, new material selection, insufficient design control, etc
Hazardous Situation: deterioration or loss of device function (unguided implant placement), fracture, contamination of operative site with foreign debris, etc
Harm: Tissue damage, revision surgery, etc
OR
“High-Level”
(3)(a)
Hazard: Contamination of operative site with foreign debris
Events Leading to Hazard: fracture caused by incorrect material choice, fracture caused by inadequate inner diameter size, etc
Hazardous Situation: increased intraoperative time, increased friction in joint, adverse tissue reaction, etc
Harm: tissue damage, revision surgery, infection, etc
And
(3)(b)
Hazard: loss/deterioration of function: implants are unguided
Events Leading to Hazard: fracture caused by incorrect material choice, fracture caused by inadequate inner diameter size, etc
Hazardous Situation: increased intraoperative time, increased joint stresses, etc
Harm: tissue damage, revision surgery, infection, etc
---
I could go on, and that is just for the hazard relating to the device failing/fracturing…. I believe another hazard exists that relates to the interface mating condition between the guide wire and the implant, and I have the same problem with that as I do with what you just read above (is “insufficient mating clearance with implant” the hazard, or is “oversized outer diameter” the hazard, or is “unguided implant” the hazard, etc?)
Thanks for any advice you can offer, and sorry for the long point – I am just so far past the point of over-thinking this whole hazards-thing that I am at a complete loss haha.
Take care,
K