Facet Joint Degeneration and ADR

[Jack-of-all-trades]

Kathleen,

I feel for you and having to go through deciding what to do. I faced the same dilemma. I did my research and came to the point where it was time to jump one way or the other. I had a sense of relief once the decision was made. Then it just became working toward my goal, a much easier thought process.

I have three level disease. L5-S1 was felt to be my pain generator. Many people have a worse looking spine than I but are asymptomatic. Many have less hard evidence but worse pain. There seems to be no definitive test or remedy for chronic back pain. I think ultimately you have to go with your gut to decide.

I finally decided on a minimally invasive PLIF with internal fixation. The reasons: At L5-S1 I had isthmic spondylolisthesis. The isthmic part indicates a fracture of the thin bone on either side of the spinal cord allowing the vertebral body to slide forward, the spondy part. The purpose of the facet joints, along with all the ligaments and muscles around the spine are to keep the vertebra from moving, mostly sliding forward on each other. Due to the tilt of the spine, L5-S1 facets have the most strain place on them when compared to the rest of the L-spine. With the type surgery I had, the facets were removed, the bone prepared and used in the prepared disc space. The area of the former facets were where the hardware was placed coupling L5 & S1.

I too was approved for disc replacement from Stenum. The disc specialist in India would not commit until he had a chance to see me in person. Both had results from MRIs going back 3 years, CTs and disc-o-gram. The docs in the USA would not consider me a candidate with moderate facet disease but the real killer was the isthmic fractures. I felt, at my age (very low 60s), that the posterior approach would be best for now, and ADR if I live to be a grumpy old man in the future (some say I'm there already). There is a greater risk at L4 thru S1, especially for males if you catch my drift, in messing up nerves that are still important by using an anterior approach. Risk to nerves related to bowel and bladder functions are also greater. If fusion at the ADR level is indicated after disc replacement, it is much harder to do. Most leave the disc in place and fuse over it, some try to remove it and fuse the joint. Again risking nerve even more as it is a bigger surgery.

Financially, it was much cheaper to have surgery in the USA than to go overseas. My insurance paid all but $1,800.00 in the USA and none for overseas. Liability concerns was a small but pertinent factor as well. Follow-up from someone who knew my case here in the USA. was important too.

Be as informed a patient as you can about your condition. When the doc comes into the exam room, work your way between him and the door till all your questions are answered. That way you won't get a Howdy Dowdy round. If you are attractive, (and all women are attractive just some a little more than others) use all the assets you can and still be ethical. It use to keep me in the exam room longer answering lots longer than I was supposed to.Your L3 level is a better place to have ADR than my L5-S1.

I will be 6 weeks out om Monday (tomorrow). All in all, things have beem much less painfull than I thought post-op.

You can PM me you have any questions about the type surgery I had. This is the procedure I had



Michael Myers

[mark-Perth]

J Spinal Disord Tech. 2003 Aug;16(4):412-7.
The implications of constraint in lumbar total disc replacement.

Huang RC, Girardi FP, Cammisa FP Jr, Wright TM.
Spine Surgery Service, Hospital for Special Surgery, New York, New York, USA. russelhuang [at] yahoo.com

Lumbar total disc replacement (TDR) is an evolving technique that has the potential to replace arthrodesis as the gold standard surgical treatment of degenerative disc disease. The interaction between host anatomy and physiology and the biomechanical properties of TDR implants will determine the quality of long-term clinical results. However, there is scant literature addressing this subject. The purpose of this article is to discuss the implications of biomechanical constraint in TDR. Based upon available data for normal motion segments and the design of two TDRs currently in clinical trials, unconstrained designs appear to have a kinematic advantage. They are more likely to provide a physiologic mobile instantaneous axis of rotation (IAR), which may explain why they display greater range of motion in vivo. Their lack of constraint may prevent excessive facet joint or capsuloligamentous loads in the extremes of flexion and extension. Furthermore, since the IAR is mobile, they may be less sensitive to small errors in implant placement. On the other hand, constrained devices appear to have an advantage in protection of the posterior elements from shear loading. Spinal shear loads of considerable magnitude occur during activities of daily living. Whether the transference of stresses to the implant and implant-bone interface is clinically significant is unknown. Although this article focuses on two specific TDR designs, future designs will need to account for the same kinematic and loading concerns regarding constraint. We hope this discussion will assist clinicians and researchers in the design, selection, and clinical comparison of present and future TDR implants.

PMID: 12902958 [PubMed - indexed for MEDLINE]

[mark-Perth]

Clin Biomech (Bristol, Avon). 2009 Feb;24(2):135-42. Epub 2009 Jan 3.
Influence of different artificial disc kinematics on spine biomechanics.

Zander T, Rohlmann A, Bergmann G.
Julius Wolff Institut, Charité-Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin, Germany.
BACKGROUND: There are several different artificial discs for the lumbar spine in clinical use. Though clinically established, little is known about the biomechanical advantages of different disc kinematics. METHODS: A validated finite element model of the lumbosacral spine was used to compare the results of total disc arthroplasty at level L4/L5 performed by simulating the kinematics of three established artificial disc prostheses (Charité, ProDisc, Activ L). For flexion, extension, lateral bending, and axial torsion, the intervertebral rotations, the locations of the helical axes of rotation, the intradiscal pressures, and the facet joint forces were evaluated at the operated and adjacent levels. FINDINGS: After insertion of an artificial disc, intervertebral rotation is reduced for flexion and increased for extension, lateral bending, and axial torsion for all studied discs at implant level. The positions of the helical axes are altered especially for lateral bending and axial torsion. Increased facet joint contact forces are predicted for the Charité disc during extension-- influenced by the existence of anterior scar tissue--and for the ProDisc and the Activ L during lateral bending and axial torsion. The studied artificial discs have only a minor effect on the adjacent levels. INTERPRETATIONS: For some load cases, total disc arthroplasty leads to considerably altered kinematics and increased facet joint contact forces at implant level. The spinal kinematic alterations due to an artificial disc exceed by far the inter-implant differences, while facet joint contact force alterations are strongly implant and load case dependent. The importance of implant kinematics is often overestimated.

PMID: 19121822 [PubMed - indexed for MEDLINE]

[mark-Perth]

Eur Spine J. 2009 January; 18(1): 89–97.
Published online 2008 November 29. doi: 10.1007/s00586-008-0836-1.

PMCID: PMC2615124

Copyright © Springer-Verlag 2008

Effect of an artificial disc on lumbar spine biomechanics: a probabilistic finite element study

Antonius Rohlmann, Anke Mann, Thomas Zander, and Georg Bergmann
Julius Wolff Institut, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
Antonius Rohlmann, Phone: +40-30-450559083, Fax: +49-30-450559980, ; Email: rohlmann [at] biomechanik.de
Corresponding author.
Received June 10, 2008; Revised October 28, 2008; Accepted November 10, 2008.
Abstract

The effects of different parameters on the mechanical behaviour of the lumbar spine were in most cases determined deterministically with only one uncertain parameter varied at a time while the others were kept fixed. Thus most parameter combinations were disregarded. The aim of the study was to determine in a probabilistic finite element study how intervertebral rotation, intradiscal pressure, and contact force in the facet joints are affected by the input parameters implant position, implant ball radius, presence of scar tissue, and gap size in the facet joints. An osseoligamentous finite element model of the lumbar spine ranging from L3 vertebra to L5/S1 intervertebral disc was used. An artificial disc with a fixed center of rotation was inserted at level L4/L5. The model was loaded with pure moments of 7.5 Nm to simulate flexion, extension, lateral bending, and axial torsion. In a probabilistic study the implant position in anterior–posterior (ap) and in lateral direction, the radius of the implant ball, and the gap size of the facet joint were varied. After implanting an artificial disc, scar tissue may develop, replacing the anterior longitudinal ligament. Thus presence and absence of scar tissue were also simulated. For each loading case studied, intervertebral rotations, intradiscal pressures and contact forces in the facet joints were calculated for 1,000 randomized input parameter combinations in order to determine the probable range of these output parameters. Intervertebral rotation at implant level varies strongly for different combinations of the input parameters. It is mainly affected by gap size, ap-position and implant ball radius for flexion, by scar tissue and implant ball radius for extension and lateral bending, and by gap size and implant ball radius for axial torsion. For extension, intervertebral rotation at implant level varied between 1.4° and 7.5°. Intradiscal pressure in the adjacent discs is only slightly affected by all input parameters. Contact forces in the facet joints at implant level vary strongly for the different combinations of the input parameters. For flexion, forces are 0 in 63% of the cases, but for small gap sizes and large implant ball radii they reach values of up to 533 N. Similar results are found for extension with a maximum predicted force of 560 N. Here the forces are mainly influenced by gap size, implant ball radius and scar tissue. The forces vary between 0 and 300 N for lateral bending and between 0 and 200 N for axial torsion. The parameters that have the greatest effect in both loading cases are the same as those for extension. Intervertebral rotation and contact force in the facet joints depend strongly on the input parameters studied. The probabilistic study shows a large variation of the results and likelihood of certain values. Clinical studies will be required to show whether or not there is a strong correlation of parameter combinations that cause high facet joint forces and low back pain after total disc replacement.

[mark-Perth]

Spine J. 2006 May-Jun;6(3):258-66.
Disc arthroplasty design influences intervertebral kinematics and facet forces.

Rousseau MA, Bradford DS, Bertagnoli R, Hu SS, Lotz JC.
Department of Orthopaedic Surgery, University of California San Francisco, San Francisco, CA 94143, USA.

BACKGROUND CONTEXT: Total disc replacement is a novel approach for dynamically stabilizing a painful intervertebral segment. While this approach is gaining popularity, and several types of implants are used, the effect of disc arthroplasty on lumbar biomechanics has not been widely reported. Consequently, beneficial or adverse effects of this procedure may not be fully realized, and data for kinematic optimization are unavailable. PURPOSE: To characterize kinematic and load transfer modifications at L5/S1 secondary to joint replacement. STUDY DESIGN: A human cadaveric biomechanical study in which the facet forces and instant axes of rotation (IAR) were measured for different spinal positions under simulated weightbearing conditions before and after total disc replacement at L5/S1 using semiconstrained (3 degrees of freedom [DOF]; Prodisc) and unconstrained (5 DOF; Charité) articulated implants. METHODS: Twelve radiographically normal human cadaveric L5/S1 joints (age range 45-64 years) were tested before and after disc replacement using Prodisc II implants (Spine Solutions, Paoli, PA) in six specimens and SB Charité III (Johnson & Johnson, New Brunswick, NJ) in six other specimens. Semiconstrained fixtures in combination with a servo-hydraulic materials testing system subjected the test specimens to a physiologic combination of compression and anterior shear. Multiple intervertebral positions were studied and included up to 6 degrees of flexion, extension, and lateral bending. The IAR was calculated for every 3-degree intervals, and the force through the facet joints was simultaneously measured using flexible intra-articular sensors. Data were analyzed using repeated-measures analysis of variance. RESULTS: During flexion/extension, the average IAR positions and directions were not significantly modified by implantation with the exception that the IAR was higher relative to S1 end plate with the Charité (p=.028). The IAR had a vertically oriented centrode throughout flexion/extension with the Prodisc (p<.001) and the Charité (p<.016). The centrode tended to be greater with the Prodisc. There was a trend that the facet force was decreased throughout flexion/extension for the Prodisc; however, this was statistically significant only at 6 degrees extension (27%, p=.013). In lateral bending, the IAR was significantly modified by Prodisc replacement, with a decreased inclination relative to S1 end plate, (ie, increased coupled axial rotation). While the IAR moved in the horizontal plane toward the side of bending, this effect was more pronounced with the Prodisc. The ipsilateral facet force was significantly increased in 6 degrees lateral bending with the Charité (85%; p=.001). CONCLUSIONS: The degree of constraint affects post-implantation kinematics and load transfer. With the Prodisc (3 DOF), the facets were partially unloaded, though the IAR did not match the fixed geometrical center of the UHMWPE. The latter observation suggests joint surface incongruence is developed during movement. With the Charité (5 DOF), the IAR was less variable, yet the facet forces tended to increase, particularly during lateral bending. These results highlight the important role the facets play in guiding movement, and that implant constraint influences facet/implant synergy. The long-term consequences of the differing kinematics on clinically important outcomes such as wear and facet arthritis have yet to be determined.

PMID: 16651219 [PubMed - indexed for MEDLINE]

[mark-Perth]

Hi Kathleen

U really need to read the full articles to get a full idea of how much extra force an ADR puts on the facets, the abstracts only give a brief idea.

I also dont believe that its proven that ADRs stop adjacent level degeneration. Thats just a hope that people have.

I have been in your situation not wanting a fusion due to the bad things I had heard and read but wished that I went straight there, and I was suitable for an ADR with no facet problems.

I can assure U it is definately not worth having surgery that will only help for a few years, U look way too young to spend the rest of your life in pain.

A common reason that ADRs need revisions is often from facet pain. Quite often these people had no facet problems when the ADRs were implanted yet over a short period there was considerable degeneration. I would hate to think what it would be like starting out already with facet problems!

I have been thru a revision and it is the worst thing U ever want to go thru and mine went well. Even if a revision goes well U will more than likely be much worse off than U R now and suffer for the rest of your life.

I know I will!

Just cause a surgeon is willing to put it in U doesnt mean that it will help U.

I would suggest that U have a discoblock done prior to any surgery to establish how much pain is actually coming from the disc. It may atleast help determine how much pain relief U may get from surgery. Its different to a discogram in that a long acting local anaesthetic is injected into the disc.

Definately think hard before U make your mind up

All the best

Mark

[WPKat]

Just cause a surgeon is willing to put it in U doesnt mean that it will help U.

You are right. My surgery last March didn't resolve the pain after everything settled down. The nerve burning exercise didn't help either and only made it worse. Both of which were suggested by my surgeon. It seems more like it's been a very painful "process of elimination" to see what's the primary cause of my back pain.

I would suggest that U have a discoblock done prior to any surgery to establish how much pain is actually coming from the disc. It may atleast help determine how much pain relief U may get from surgery. Its different to a discogram in that a long acting local anaesthetic is injected into the disc.

That's a great idea, Mark, I will definitely ask about the discoblock before they do the discogram. I appreciate your bringing it up since my surgeon did not suggest it and I was not aware of the test. It sounds a whole lot better than purposely provoking pain

The sad reality is that I'm already facing the rest of my life in pain. Believe me, however, I get that I don't want to make it worse.

Thanks ... K

[WPKat]

Kathleen,

I feel for you and having to go through deciding what to do. I faced the same dilemma. I did my research and came to the point where it was time to jump one way or the other. I had a sense of relief once the decision was made. Then it just became working toward my goal, a much easier thought process.

I have three level disease. L5-S1 was felt to be my pain generator. Many people have a worse looking spine than I but are asymptomatic. Many have less hard evidence but worse pain. There seems to be no definitive test or remedy for chronic back pain. I think ultimately you have to go with your gut to decide.

I finally decided on a minimally invasive PLIF with internal fixation. The reasons: At L5-S1 I had isthmic spondylolisthesis. The isthmic part indicates a fracture of the thin bone on either side of the spinal cord allowing the vertebral body to slide forward, the spondy part. The purpose of the facet joints, along with all the ligaments and muscles around the spine are to keep the vertebra from moving, mostly sliding forward on each other. Due to the tilt of the spine, L5-S1 facets have the most strain place on them when compared to the rest of the L-spine. With the type surgery I had, the facets were removed, the bone prepared and used in the prepared disc space. The area of the former facets were where the hardware was placed coupling L4 and L5.

I too was approved for disc replacement from Stenum. The disc specialist in India would not commit until he had a chance to see me in person. Both had results from MRIs going back 3 years, CTs and disc-o-gram. The docs in the USA would not consider me a candidate with moderate facet disease but the real killer was the isthmic fractures. I felt, at my age (very low 60s), that the posterior approach would be best for now, and ADR if I live to be a grumpy old man in the future (some say I'm there already). There is a greater risk at L4 thru S1, especially for males if you catch my drift, in messing up nerves that are still important by using an anterior approach. Risk to nerves related to bowel and bladder functions are also greater. If fusion at the ADR level is indicated after disc replacement, it is much harder to do. Most leave the disc in place and fuse over it, some try to remove it and fuse the joint. Again risking nerve even more as it is a bigger surgery.

Financially, it was much cheaper to have surgery in the USA than to go overseas. My insurance paid all but $1,800.00 in the USA and none for overseas. Liability concerns was a small but pertinent factor as well. Follow-up from someone who knew my case here in the USA. was important too.

Be as informed a patient as you can about your condition. When the doc comes into the exam room, work your way between him and the door till all your questions are answered. That way you won't get a howdy Dowdy round. If you are attractive, (and all women are attractive just some a little more than others) use all the assets you can and still be ethical. It use to keep me in the exam room longer answering lots longer than I was supposed to.Your L3 level is a better place to have ADR than my L5-S1.

I will be 6 weeks out om Monday (tomorrow). All in all, things have beem much less painfull than I thought post-op.

You can PM me you have any questions about the type surgery I had. This is the procedure I had <a href="http://s614.photobucket.com/albums/tt227/flylowguy/?action=view&current=DSC01081.jpg" target="_blank"><img src="http://i614.photobucket.com/albums/tt227/flylowguy/DSC01081.jpg" border="0" alt="In Liersville Alaska"></a>

Michael Myers

Michael,

I took a look at your x-ray and cringed. Dang.

I had to chuckle when I read your suggestion on using your assets and standing in front of the door to get all your questions answered. I always go in with a list of questions. The trouble has been that I don't always know the right questions to ask, the answer I received was vague or the question was ignored entirely.

Curious about a couple of things:

• How painful was your discogram (next thing on my list)?
• How many ADRs did Stenum recommend for you?

Please let me know how things progress for you as you heal from your recent surgery.

Thanks for your input ... K

[Justin]

Michael and Mark,

Thanks for sharing your thoughts & experiences!

That's a great idea, Mark, I will definitely ask about the discoblock before they do the discogram. I appreciate your bringing it up since my surgeon did not suggest it and I was not aware of the test. It sounds a whole lot better than purposely provoking pain

The sad reality is that I'm already facing the rest of my life in pain. Believe me, however, I get that I don't want to make it worse.

Thanks ... K

Hi Kathleen. I completely understand your frustration with spine issues and the thought of living the rest of your life in pain is scary (I have been down this thought process many times myself).

Ultimately, your research will pay off. Although spine surgery is not a "fix-all," it has helped many people get back to the "good of life." Exhaust all diagnostic tests and keep doing your homework--it will greatly help when you know it is time to move forward and what options are available to you.

I wish you nothing short of a full life without pain. :thumpup:

[Jack-of-all-trades]

I got into to big of a rush last night to get to bed and clicked on my pictures instead of the link to the procedure I had done. Hopefully, this is it. ORLive, Inc.: Minimally Invasive Posterior Lumbar Interbody Fusion (PLIF) My computer skills are definitely lacking. Sorry about that.

Also with my fusion, instrumentation was done to L5-S1 and not L4-5. I corrected that mistake earlier.

Just another thought. While fusion may put more stress on the other discs, I don't plan to put the same stresses on any of them that I once did. No more water/snow skiing. No more toting big people on a backboard or hunkered over people in wrecked cars, tractors or fallen debris like I did when I was a paramedic (before PA school, this was how I paid the rent). No more Judo/Karate. Anyway, I sure we all have abused or backs in one way or the other that we don't plan on in the future. I for one plan to put less stress on my remaining disc than I did on all 5 before back pain showed it's ugly head. I also tend to get carried away with metaphors