SCUBA and Spinal Kinetics' M6

[jss]

In Nov'09 I had two Spinal Kinetics M6's implanted at C3/4 and C6/7. In Dec'09 we booked nine days on Isla Mujeres, Mexico for July'10. Only then did it occur to me that my M6's might not be SCUBA friendly, so I called Spinal Kinetics to find out. Here's what I found out.

Spinal Kinetics has never tested the device under SCUBA conditions, but thinks that it should perform properly; but they are not certain. They have no plans to test the device under those conditions. The polymer sheath around the M6 nucleus does NOT form an air-tight seal. The sheath contains two vent ports. When the device is manufactured, the nucleus and polymer weave is covered with a polymer sheath. All 'empty space' inside of that sheath contains whatever atmosphere that happened to be floating by when the sheath was installed at the manufacturing facility. When the device is implanted into the host (me), it still contains that gas.

Over time, the host's interstitial fluid seeps into the vent ports and the gas seeps out and is absorbed by and disposed of by the host. This potentially presents a problem for the M6 and SCUBA. The increased pressures of SCUBA at deeper depths makes greater quantities of atmospheric gasses soluble in our blood and interstitial fluid. As we ascend from those depths the gasses slowly become insoluble and come out of the solution of our blood. If we ascend too fast, there can be enough gas come out of solution that bubbles can from in our blood and tissues; a condition known as "The Bends". In severe case this is fatal.

How much of this super saturated interstitial fluid vents into the M6 during a dive? Is there enough super saturated fluid still inside the M6 on the surface that a bubble can form? If so, can this deform the M6's sheath enough to push on the spinal cord or nerve root? Could a bubble be large enough to deform the sheath enough to damage the sheath?

While the Spinal Kinetics representative I spoke with thought that there should be no problem, his answer to each of those questions was, "I don't know."

I doubt that SCUBA is a problem for the M6, and if money were no object and I could have the devices replaced if they were damaged, I'd dive Isla Mujeres. As such is not the case, I'll resolve to sit on the beach, reading and drinking, while everyone else is diving. If there is a dive of no greater than 33 feet, I'll go ahead and participate as gas saturation down to that depth is not an issue.

Something to consider if you're looking at the M6.

[Justin]

Jeff,

Thanks for posting this information! It is much appreciated. Have fun!

[Katie]

Wow, great thinking! We sure have to be on our toes with these devices, don't we. While it will never apply to me, I thank you for bringing it to our attention. Smart man.

And enjoy your vacation for what it is.....

[JK2234]

Im confused, this went over my head...

[Katie]

So is your vacation coming up soon jss?

[Justin]

So is your vacation coming up soon jss?

I think Jeff went during the first week in June.

[Katie]

Oh OK, I thought he was just going now, as his first post said July. Maybe he changed it.

[Justin]

Oh OK, I thought he was just going now, as his first post said July. Maybe he changed it.

You're right Katie. I misread what he posted.

[jss]

Ladies and Gentlemen,

We're just back from Isla Mujeres, Mexico and we had a GREAT time! Specifically to the point of this thread, I managed one 45 minute dive at a maximum depth of 28 feet. There was no decompression required at that depth, so the SCUBA problem that theoretically exists with the M6 shouldn't have been a problem at that depth. As far as I can tell my pair of M6's did fine.

[Katie]

Congratulations! Your new life is officially on track