Avascular Bone Necrosis

[featherland]

I don't suppose that there are MANY freedivers on the forum that have been participating in this hobby for 5 decades, like my father has (Bill, the Deeper Blue Old Guy from Kona), but just in case I thought I'd throw out a question...

First an update...
My Dad is currently in the hospital undergoing total hip replacement surgery because of avascular bone necrosis of the "ball" at the end of the femur. Surgery was on Tuesday and he's doing OK and was up on his feet yesterday. The physical therapist told him that she wanted him to walk 10 feet... he did 250. That's my Dad alright.

Of course they called in a crash cart shortly thereafter <sigh>

He hopes to be back home on Friday.

The question to the forum is... this disease has been seen in long term deep depth SCUBA divers:

http://www.uksdmc.co.uk/main/Diver%2...eonecrosis.htm

... but has anyone heard of this in long term, deep depth freedivers??

As if holding his breath seven and a half minutes wasn't dangerous enough!

[Erik]

What about the thousands of constant quick ascents to 8000' cabin pressure in the planes he flew?
I wonder if there's any history with 'old' (sorry Bill) pilots?
Get well soon,
Erik Y.

[cdavis]

Glad to hear Bill is doing well. Get well quick!

I've never seen anything relating this condition to free diving, but free divers who go deep repeatedly certainly should be at risk. Enough bottom time to accumulate some N2 and lots of rapid assents should create at least some risk. Flying and free diving, together, would increase that risk. Nasty thought, I'm going on 4 decades, but not near as deep as Bill.

Connor

[smellsfishy]

Sort of on topic: http://www.msnbc.msn.com/id/6750782/

Bill, get well soon !

[flyboy748]

Get well soon Bill! I'm sure something like a hip replacement won't slow you down too much if you have anything to say about it!

Originally Posted by Erik

What about the thousands of constant quick ascents to 8000' cabin pressure in the planes he flew?
I wonder if there's any history with 'old' (sorry Bill) pilots?
Get well soon,
Erik Y.

I've never seen flying mentioned in reference to avascular necrosis, however I think I've only read of it in diving related publications. Erik's post got me to wonderin' though. So I dusted off some books I haven't referred to for far too long, dug out my calculator and put on a pot of coffee Here's what I found.

The pressure change in an ascent from 0'-10,000' cabin altitude is 2.5 PSI. That's the pressure change experienced while surfacing from 5 and a half feet or so. Percentagewise (if that's a word! ) however we're looking at a 17% decrease in pressure from 0-10,000' equivalent to a return to the surface from just less than 7 feet. So it would seem that flying with cabin altitudes of < 10,000' would have no more effect than diving at depths not exceeding 7 feet. And as far as the speed of the ascent goes, pressurized aircraft usually control the cabin pressure changes to values of 500 feet/minute or less making it a 16 minute ascent to 8000' or 20 min to 10,000'. Unpressurized aircraft usually climb at less than 1500 fpm, making that change a little faster.

All that said however, we know that flying after diving can only exacerbate the problem, as Connor pointed out. Weather flying after freediving poses any great risk is to my knowledge unconfirmed, but it would stand to reason that risk is at very least increased, especially after deep freediving. The pressure change from -60m to that same +10,000' is 90.7 psi or a wopping 88% decrease! However to put that in perspective, you've already experienced an 86% pressure decrease returning to the surface from -60m.

Although I haven't read anything referencing freediving to this disease, since we know that freedivers can get bent, it would also stand to reason that long term freedivers could (at least in theory) be more susceptible. It seems that whales are!

Interesting question indeed! Maybe I'll take up golf or something...

Cheers,
Aaron