Revision/Replacement Infection Risk Trajectory - Shocked

[defiant]

Well, two things come to mind:

The study does have very few cases. The first implant (first revision or first implant? Not clear to me...) group is 44 people. Already that is a very small sample group.
And then it just gets worse. Talking about a 50% risk on the 4:th (implant or revision?) when the population consists of 8 people is pretty useless.

On the other hand, infection is a real thing, it happens, and the maths does not work in favor of multiple surgeries.
Let us take a few examples of accumulated infection risk over 5 surgeries (not many would need more than 4 revisions) based on different risks on each surgery.

Infection risk.JPG

This will clearly show that if you pick a surgeon with poor skills on avoiding infection, probability of getting infected increases to pretty ugly numbers as number of surgeries go by.
Why the odd infection risk for the first surgery?
Because a study I read showed these infection risk by volume:

Risk vs volume.JPG

I put Eid in the table for reference. He publishes his infection risk data on his web page. Maybe there are other super skilled surgeons out there as well with similar records as him.
But the takeaway is - Eid (or someone with his skills) will have the same accumulated infection risk over 4-5 surgeries as the average doc has in one surgery.
I have got hammered over the years by some morons for giving one advice only in my signature and in plenty of posts - Choose a world class surgeon.
Many have said that there are plenty of fantastic surgeons in the local hillbilly hospitals. Yeah, right. Maybe there is.
But why take the risk? The odds are against you when you pick a low-volume surgeon, while the odds are definitely in your favor when you pick one of the very, very best.

Your choice, your dick.

This gives me a lot more encouragement. And it does make sense.

The study makes no mention of which surgeons were performing these implants nor offers any information as to their infection rates.

It does stand to reason that going to a surgeon like Eid, Ralph, Hakky, Perito, etc etc (the A list basically) would dramatically reduce your risk of infection down the line.

One would also hope that in 10 years, the surgical technique and devices will be even more advanced and offer greater protection against infection as well as hopefully, longer lasting implants.

Medical science, and I believe this field being no exception, have come a long, long way in the last ten years alone and tech advances exponentially.

Merrix, where did you get these numbers? Or are they your own statistical forecasts?

[Pau1pau1]

I went to Ralph in the uk and he said just under 1% for first implant rising to 3% there after.
So the 2nd implant would also have a 3% chance. Not 6% , that’s the 2revisions added together.

[defiant]

I went to Ralph in the uk and he said just under 1% for first implant rising to 3% there after.
So the 2nd implant would also have a 3% chance. Not 6% , that’s the 2revisions added together.

Oh interesting. You received an implant from Ralph?

I didn’t understand what you said though, so sorry.

You mean 1st is 1%, 2nd is 3% and 3rd is 6%?

[ViaSwiss]

There are tons of variables involved in infections rates that this study does not account for. I agree in that its just a poorly designed study.

Already mentioned
-why such a small dependent group
-who are the docs performing these operations and what is there overall infection rates

Not mentioned
-hospital or ambulatory centers?
-health status of patients (overweight?, diabetes, etc.) can cause increase in infection rates
-hell, I even posted a study the other month showing that winter months (less humid) have lower infection rates than summer months

[merrix]

Merrix, where did you get these numbers? Or are they your own statistical forecasts?

The first table is just mathematics. If the risk of infection per surgery is what is listed in row 1, then obviously that is the risk to get infected if you undergo one surgery.
Subsequent rows shows the accumulated risk of getting infected as the number of surgeries add up.

Second table is from a study which examined the correlation between surgeons' experience and risk of infection.
That study listed the total number of infections as 2.5% of surgeries. More when you go to a low volume surgeon and less when you go to a high-volume surgeon.

But Eid (and probably a few other equally skilled surgeons) statistics of 0.6% is still miles ahead even other high volume surgeons.

I went to Ralph in the uk and he said just under 1% for first implant rising to 3% there after.
So the 2nd implant would also have a 3% chance. Not 6% , that’s the 2revisions added together.

Oh interesting. You received an implant from Ralph?

I didn’t understand what you said though, so sorry.

You mean 1st is 1%, 2nd is 3% and 3rd is 6%?

Statistically, the first implant, the so called virgin implant, has lower risk of infection than revisions.
So the 1% for the virgin implant and 3% for revisions might be correct data for this particular surgeon.
However, in the case of Eid, the statistics on his web page includes all surgeries he does - virgin implants and revisions combined.
And his infection risk for all surgeries combined is 0.6%.
Probably a lot lower for virgin implants and a little higher for revisions (assuming he does more revisions than virgins).

In the case above, with 1% risk for virgin implants and 3% risk for revisions, the accumulated risk to get an infection would be:
If only doing 1 surgery (the virgin implant): 1% (obviously).
If needing 1 revision: 1-99%*97%=4%
If needing 2 revisions: 1-99%*97%*97%=6.9%
If needing 3 revisions: 1-99%*97%*97%*97%=9.6%

That is the accumulated risk of getting infected during that number of surgeries. Random events have no memory though, so if you have gotten through 2 revisions without getting infected, you still only have a 3% risk of getting infected during your third revision of course. The 9.6% risk is what you start with from the beginning, the risk that you will get infected during your future 4 surgeries.

And with Eid that risk would be 1-99,4%*99.4%*99.4%*99.4% = 2.4%.

[defiant]

Merrix, where did you get these numbers? Or are they your own statistical forecasts?

The first table is just mathematics. If the risk of infection per surgery is what is listed in row 1, then obviously that is the risk to get infected if you undergo one surgery.
Subsequent rows shows the accumulated risk of getting infected as the number of surgeries add up.

Second table is from a study which examined the correlation between surgeons' experience and risk of infection.
That study listed the total number of infections as 2.5% of surgeries. More when you go to a low volume surgeon and less when you go to a high-volume surgeon.

But Eid (and probably a few other equally skilled surgeons) statistics of 0.6% is still miles ahead even other high volume surgeons.

I went to Ralph in the uk and he said just under 1% for first implant rising to 3% there after.
So the 2nd implant would also have a 3% chance. Not 6% , that’s the 2revisions added together.

Oh interesting. You received an implant from Ralph?

I didn’t understand what you said though, so sorry.

You mean 1st is 1%, 2nd is 3% and 3rd is 6%?

Statistically, the first implant, the so called virgin implant, has lower risk of infection than revisions.
So the 1% for the virgin implant and 3% for revisions might be correct data for this particular surgeon.
However, in the case of Eid, the statistics on his web page includes all surgeries he does - virgin implants and revisions combined.
And his infection risk for all surgeries combined is 0.6%.
Probably a lot lower for virgin implants and a little higher for revisions (assuming he does more revisions than virgins).

In the case above, with 1% risk for virgin implants and 3% risk for revisions, the accumulated risk to get an infection would be:
If only doing 1 surgery (the virgin implant): 1% (obviously).
If needing 1 revision: 1-99%*97%=4%
If needing 2 revisions: 1-99%*97%*97%=6.9%
If needing 3 revisions: 1-99%*97%*97%*97%=9.6%

That is the accumulated risk of getting infected during that number of surgeries. Random events have no memory though, so if you have gotten through 2 revisions without getting infected, you still only have a 3% risk of getting infected during your third revision of course. The 9.6% risk is what you start with from the beginning, the risk that you will get infected during your future 4 surgeries.

And with Eid that risk would be 1-99,4%*99.4%*99.4%*99.4% = 2.4%.

I see.

Well, neither Eid nor certainly Ralph will be practicing in 20 years but one would hope that, as mentioned before, infection prevention techniques will advance further as will the devices themselves.

And I’m sure there will be highly highly skilled implanters going forward.

[TwoStep]

Ok I got hold of the full paper. I apologize that I commented based on my misunderstanding of the abstract before. The main content of the paper is retrospective and not about the result of their own surgery.
At this point one could speculate that the numbers are just an expression of selection bias: maybe after 5 surgeries most patients were fed up, and only those experiencing infection would bother to seek out a new hospital (Mayo Clinic) for revision? That seems like a plausible explanation.

However, there is an interesting comment about the outcomes of their own surgery:

“We plan to publish a separate manuscript reporting our surgical outcomes of the men described in this study. Briefly, however, in 12 men who underwent implantation with a history of two prior implant operations our infection rate was 11% (1/9), whereas 30% of men with a history of ≥3 prior implant surgeries experienced infection (3/10).”

Since this result is prospective it does not suffer the same selection bias in my optimistic speculation above. I think it supports the conclusion that more prior surgeries increase the infection risk in a single future surgery.

[bjb0606]

I had my 3rd revision in a six month period yesterday. I believe had I picked the right Doctor to start with I would have only had 1 this year. So listen to these guys when they tell you to research your Doctor. I think they're doing better I had 5 bags of different antibiotics.

2022 gotta be better!

[Gt1956]

I had my 3rd revision in a six month period yesterday. I believe had I picked the right Doctor to start with I would have only had 1 this year. So listen to these guys when they tell you to research your Doctor. I think they're doing better I had 5 bags of different antibiotics.
2022 gotta be better!

I sure hope that you've turned the corner on this. 3 sugeries in 1 year is a rough year.
As you imply in your post. Not all doctors are equal. I think a better description is they're on a bell curve. About the same number are class A doctors as are a total failure. The rest fall between barely competent to fairly good.
While we all want the top surgeon. I'm thinking anybody in the top 20% or so should be good. Still not great odds.
Back to this infection study. I sure wish that it went into the details of what & how serious the infection was.

[OregonStrong]

that study is pretty much worthless. You can't make any inference with only 2 participants in the 5 revisions group. I would highly suspect anyone that has had to undergo 5 surgeries probably has something wrong medically that would also put them at risk, maybe diabetes, vascular dz, etc, things that can affect wound healing from previous implants, dehiscence, etc. As others said,, we also don't know about the surgeon involved. I think you probably need at minimum a group of about 200 people to get a good idea of statistics with that many revisions. That will be hard to find though, in 10 years there probably wouldn't even be more than 15 to 20 worldwide that have had 5 of these surgeries.