In case you missed this important topic...
 

http://www.adrsupport.org/forums/f51...ications-9620/

:look:

Best wishes for your side.

reference Activ-L documents, LINK

The biomechanics of lumbar levels varies slightly between L4-L5 and L5-S1. There is more compressive shear at L5-S1 because of vertebral angles, in general, and this can be erased by individual biologic variability of vert.angles and facets (angles) add another variable x person within ranges.

Look at the BBraun site / docs and you will note there is a specific mention of L5-S1. I

The Activ-L S1 plate is an additional option for the surgeon to address patient`s anatomy.

There are patients who have a sacrum with a rather round or egg shaped cross-sectional footprint.

For those patients the S1 plate has rounded posterior edges and can therefore be placed close to the posterior rim of the S1 vertebra without these edges protruding into the spinal canal.

This might enable the surgeon to use a larger size compared to the standard plate, which reduces the risk of subsidence and nerve root
irritation.

The S1 plate is just an option, there are of course cases, where the standard plate will fit better. X-ray templates are available which can be used for preoperative planning in order to define the appropriate plate type.

Anterior or oblique insertions are possible with a minimum disc height of 8.5mm.


Fixation: activ-L can have a keel like ProDisc or spikes. There are biomechanical tests showing better long term stress results, less chance of hiccups with spike-only. It is only lab testing, not in-vivo.

Hi,

I am in a similar position, I believe I may be looking at a 2 level l3-l 5. I am having my discogram on 12/1/11, hopefully will know more. I have pretty much decided on Dr. Clavel assuming he wants my case:)

It is a long arduous and scary decision making process, I have found this site to be extremely helpful. Good luck with your decision process. In the end we all make what seems best for us:look:

Dingie

Hi Ben,
 

I have just had a 2nd adr surgery with Mr. Boeree, and thank God every single day. I have alot of issues with a ProDisc C but I do not know if the the lumbar ones are problematic.
I would absolutely recommend Mr. Boeree, it was the best decision I have made in my life, and I spoke with Drs B, Zeegers, both analyzed my case, dr zigler in tbi, the fda limits the adr to only prodisc, and I would NOT want to chance having another one in my spine.
I wish you safety, and a pain-free future.
Christine

An interruption made me post before finishing the draft response above.

The minimum disc height ~may be of interest depending on a patient's MRI translation into a metric measurement. There is talk of over distraction pain that I acknowledge. Maybe the posterior longitudinal ligamet is innervated. The facet joints need to line up is a major factor.

The footprint Anterior-Posterior (AP) and Lateral is ~important so the ADR / TDR sits on cortical bone, not the cancellous (or trabecular, soft porous interior) bone.
http://www.delawarebackpain.com/pati...anatomy_17.gif
Small or incorrectly sized implants will lead to subsidence, sinking into the vertebrae. Subsidence will mean the facet joints will not line up correctly. Subsidence will be a reason for re-operation and defaulting to Fusion.

Subsidence was listed as a significant factor in the early ADR / TDR operations. "Complications of Artificial Disc Replacement: A Report of 27 Patients with the SB Charite´ Disc" van Ooij et al, 2003 Journal of Spinal Disorders & Techniques, Vol. 16, No. 4, pp. 369–383.

"subsidence of the prosthesis in 16" © 2003 Lippincott Williams & Wilkins, Inc., Philadelphi

A personalized disc replacement is a good concept. Biologic variabillity is normal. Subsidence does not appear to be a major ADR / TDR issue today because of surgical training or awareness created with the earlier patients where the literature comments by surgeons mentioned "size mis-match".

The latest Canadian study published 2010 (?) Link mentioned subsidence: average 1.7 mm (range 0-4.8 mm). Full text of the Canadian study is available (LINK). Figure 1 showing subsidence and radiographic disc size illustrates a ~possible footprint mismatch to my "untrained eye". The device sizes may be limited and that was the best match.

http://www.ncbi.nlm.nih.gov/pmc/arti.../0530408f1.jpgSubsidence was present in 44 of 53 (83%) patients at the L5–S1 level and was exclusively seen at the posterior part of the inferior end plate of L5. The mean subsidence was 1.7 (range 0– 4.8) mm, meas ured at 3 months after surgery. Although there was a marginal progression of subsidence beyond this time point, it was not statistically significant. Subsidence had no effect on the range of motion at the replaced segment and did not correlate with clinical outcome. In patients who underwent an L4–5 TDA, subsidence occurred at both end plates: mean subsidence was 0.9 mm at the inferior end plate of L4 and 1.75 mm at the superior end plate of L5.

The Chinese study Oct 2010, Zhonghua Yi Xue Za Zhi LINK, on 1 and 2 level Charite' for up to 60 months listed "no subsidence".

activ-L
"Clinical results show, that in approx 47.5 % the application of a small height (less then 9 mm) is indicated." (The activL quote is directly from the BBraun literature / pdf, this requires a look-up on pubmed for clinical reference? I believe the numbers on are on the hard disk)
S = (26 x 31)
M = (28 x 34.5)
L = (30 x 39)
XL = (33 x 40)

ProDisc II L (LINK) Product Insert
10 mm minimum height
m = (27 x 34.5)
L = (30 x 39)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~
LINK-Full Text
Eur Spine J. 2008 Nov;17(11):1470-5. Epub 2008 Sep 13.
Footprint mismatch in lumbar total disc arthroplasty.
Gstoettner M, Heider D, Liebensteiner M, Bach CM.
Department of Orthopaedic Surgery, Medical University Innsbruck, Innsbruck, Austria
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Clin Biomech (Bristol, Avon). 1997;12 Suppl 1:S1-S63.
Precision measurement of disc height, vertebral height and sagittal plane displacement from lateral radiographic views of the lumbar spine.
Frobin W, Brinckmann P, Biggemann M, Tillotson M, Burton K.

Christine,

Thank you for your message. I take from your message that you did both procedures with Dr Boeree and that he used the Prodisc for you?

Many thanks,

Ben

Dear Slackwater,

Thank you very much for taking the time to write and provide such extensive information. I really appreciate it.

You have provided another important aspect to consider; subsidence. I have not reviewed the information at length yet but it appears to suggest that a "custom" fit option may be best given that each persons dimensions and issues are unique and due to the possibility of subsidence.

I will review the information at length.

Thank you again.

Ben

hi
 

i think nick does the m6L

Yes, Mr Boeree is not a fan of the Prodisc, and currently prefers M6.

Hi Ben,
 

My ProDisc C was done in 2009 here in Tampa.

Nick Boeree did the M6 a level above, and decided not to remove the (misaligned) ProDisc as it is doing it's job - removal is not a good option due to the large keels.