SpinalKinetics: Future Cervical ADR, M6

[Slackwater]

http://www.spinalkinetics.com/m6overview.html

SpinalKinetics upgraded their web site. The
SpinalKinetics M6 Cervical artificial disc
has more pics, explanations.

The different factors, possibly advantageous,
seen by this limited view are:

<LI>controlled range of motion (fiber simulated annulus)
<LI>shock absorption (viscoelastic, allows compression)
<LI>sheath (debris migration limited)
<LI>titanium (imaging advantage)

The M6 has some European use, although I have not seen
trial report data. SpinalKinetics will be at the
Orthopaedic Research Society meeting in SF March 2008;
there may be more "data" at that time.

ps:
fiber is uhmwpe, smaller, but similar to what I've seen on sailboats.

[annapurna]

Titanium shouldn't have any significant imaging advantage over other metals used; it would certainly still cause problems for MRI and CT. Otherwise, a very interesting ADR.

[Slackwater]

Originally posted by annapurna:
Titanium shouldn't have any significant imaging advantage over other metals used; it would certainly still cause problems for MRI and CT. Otherwise, a very interesting ADR.

I made the comment on titanium above as an after thought,
vaguely remembering something I had read. See the conclusion
below from pubmed.gov for a small test(N=20?). I do not have the full-article printed
out to tell anything other than what is in the abstract which gives a limited view on the data.

Another reference, European Spine Journal, not shown below.
A 1999 reference to "Virtues and drawbacks of titanium alloy aneurysm clips"
that stated titanium "artifacts on CT and MR are minor as compared to the
cobalt alloy clips used previously"

How much does it matter? Without the full-text article I can't tell.
What do they mean when they say accurate?? Unknown.
There are lesser degrees of accuracy that are useable and allowed in
most situations; it's relative. Improved accuracy with titanium, probably.
?Titanium required? maybe not mandatory. Titanium to my limited knowledge is hard,
or expensive to machine, ... FDA tentatively approved ProDisc-C, so
I assume there are other much more important criteria (patients' trial results).

Agree the ADR device is ~interesting, viscoelastic, allows compression strikes a
resonant chord in this lay person reading, ...



===================
Spine. 2007 Mar 15;32(6):673-80
Magnetic resonance imaging clarity of the Bryan, Prodisc-C,
Prestige LP, and PCM cervical arthroplasty devices

Sekhon LH, Duggal N, Lynch JJ, Haid RW, Heller JG, Riew KD, Seex K, Anderson PA.
SpineNevada, Reno, NV 89502, USA

STUDY DESIGN: Prospective, randomized, controlled and double-blinded study
on imaging of artificial discs.

OBJECTIVE: The purpose of this study is to compare
postoperative imaging characteristics of the 4 currently
available cervical arthroplasty devices at the level of
implantation and at adjacent levels.

SUMMARY OF BACKGROUND DATA: Cervical arthroplasty is being performed increasingly
frequently for degenerative disc disease and, in most cases, with frank neural compression.
Unlike lumbar arthroplasty, performed mainly for axial back pain, decompression of neural
elements may need to be confirmed with postoperative imaging after cervical arthroplasty.

METHODS: Preoperative and postoperative magnetic resonance imaging scans of 20 patients
who had undergone cervical arthroplasty were assessed for imaging quality. Five cases each of the

<LI>Bryan (Medtronic Sofamor Danek, Memphis, TN),
<LI>Prodisc-C (Synthes Spine, Paoli, PA),
<LI>Prestige LP (Medtronic Sofamor Danek), and
<LI>PCM devices (Cervitech, Rockaway, NJ)

were analyzed. Six blinded spinal surgeons scored twice sagittal and axial
T2-weighted images using the Jarvik 4-point scale. Statistical analysis
was performed comparing quality before surgery and after disc implantation
at the operated and adjacent levels and between implant types.

RESULTS: Moderate intraobserver and interobserver reliability was noted.
Preoperative images of patients in all implant groups had high-quality images
at operative and adjacent levels. The Bryan and Prestige LP devices allowed
satisfactory visualization of the canal, exit foramina, cord, and adjacent
levels after arthroplasty. Visualization was significantly impaired in all
PCM and Prodisc-C cases at the operated level in both the spinal canal and
neural foramina. At the adjacent levels, image quality was statistically
poorer in the PCM and Prodisc-C than those of Prestige LP or Bryan.

CONCLUSIONS: Postoperative visualization of neural structures and adjacent
levels after cervical arthroplasty is variable among current available devices.

<LI>Devices containing nontitanium metals (cobalt-chrome-molybdenum alloys in the PCM and Prodisc-C) prevent accurate postoperative assessment with magnetic resonance imaging at the surgical and adjacent levels.

<LI>Titanium devices, with or without polyethylene (Bryan disc or Prestige LP), allow for satisfactory monitoring of the adjacent and operated levels.

This information is crucial for any surgeon who wishes to assess adequacy of neural decompression and where monitoring of adjacent levels is desired.

PMID: 17413473

Check it out.. they just performed first M6-C into a patient here in the US.
http://www.bizjournals.com/sanantonio/othercities/sanjo...26400^1604805&page=2

I'd sure like to have one of these at c5/6.
Bob

[Harrison]

Please see related discussion, including concerns, at:

http://adrsupport.org/eve/forums/a/t...1/m/1671099403

help me understand how cervical ADR's go to market. Does the M6-C have shorter path to market based on Pro-Disc-C having just received FDA approval after a lengthy study? I've read the SpinalKinetics M6-C was implanted in the first US patient earlier this month...was that a FDA trial or what exactly was it? Also, that a Dr. in Mexico City implanted an M6-C under a program that is closely monitored by our beloved FDA... what's up with that?
I'm no surgeon, but this device seems like it could be (more) easily replaced than some of the others (e.g., cervicore, prestige ST). I'm 46 years old and need/want one or two cervical ADR's.. and I'm totally OK with the idea of having to replace them after 10 or 15 years.. assuming I don't age prematurely (like my c5/6/7 discs did). I would hope I could undergo re-replacement ADR surgery when it's necessary (10 or 15 years from now).
Thanks, Bob