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Re: IVD Pressure

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  • Re: IVD Pressure

    Dear netters

    a while ago I posted the following querry:

    I am interested in measuring pressure in cadaveric intervertebral discs in an
    effort to better understand disc pressure distribution. I am planning on
    inserting a miniaturized strain gauge pressure sensor through a needle of no
    more than 1 to 2 mm diameter. I have looked around in the catalogues that I
    have but did not find any strain gauges small enough to fit through the
    needle. Any advice or help would be most welcomed.
    As is the custom, I will post a summary of all responses received.

    So as promised here are the responses I received.
    Thanks to all who answered. The information I received was very valuable.

    Dear Dr. Baramki;
    I was surprised by your plan to insert a miniature pressure transducer
    into IVD. It would be the simplest/easiest way to measure the IVD
    pressure. However, the experimental artifact from inserting a foreign
    structure into the tissue will be enormous. In fact, I have thought about
    doing the same thing to measure the pressure within IVD, but gave up.
    Anyhow, here is a company for the miniature pressure transducer;
    Precision Measurement Company
    P.O. Box 7676
    Ann Arbor, MI 48107
    Tel/Fax: 313-995-0041

    If you receive any other suggestions from other netters, I will
    appreciate if you post it later on.

    J.K. 'Francis' Suh, Ph.D.
    Assist. Prof.
    Dept. of Orthopaedic Surgery
    Univ. of Pittsburgh
    Pittsburgh, PA 15213
    Tel: 412-648-1985
    Fax: 412-648-2001

    Try Millar Instruments in Houston, Texas (800) 669-2343. Michelle White
    is a clinical specialist who is very sharp. They have 2 and 3 french sizes
    (1mm and .67 mm needels) Good Luck.
    Michael Orendurff, Shriners Hospital, Portland, OR.

    I get mine from a company called Gaeltec
    Isle of Skye
    IV55 8GU
    Telephone +44-1470 521385

    They have a U.S. agent Medical Measurements Inc.
    53 Main Street
    NJ 07601
    Telepohone 201-489 9400
    The transducer is validated in:

    McNally,Donal Stewart; Adams,MA; Goodship,AE (1992): Development and
    validation of a new transducer for intradiscal pressure measurement. J.
    Biomed. Eng. 14, 495-498.

    The technique for geting stress distributions is detailed in:

    McNally,Donal Stewart; Adams,MA (1992): Internal disc mechanics as revealed
    by stress profilometry. Spine 17, 66-73.
    Other ineresting papers in the same series are:

    McNally,Donal Stewart; Adams,MA; Goodship,AE (1993): Can intervertebral
    disc prolapse be predicted by disc mechanics. Spine 18, 1525-1530.

    Adams,MA; McNally,Donal Stewart; Chinn,H; Dolan,P (1994): Posture and the
    compressive strength of the lumbar spine. Clin. Biomech. 9, 5-14.

    Have fun!

    Donal McNally

    Donal McNally, Action Research Lecturer in Anatomy, Department of Anatomy
    University of Bristol, Southwell Street, Bristol BS2 8EJ - Tel 0117-928 8349 - FAX 0117-925 4794
    In my last employment with the Texas Back Institute Research
    Foundation, we studied this same subject. We used Millar
    Pressure Transducers to measure the intervertebral pressure
    during flexion and extension. We were comparing the effects of
    spinal instrumentation to disc pressure. We have published the
    "Intradiscal pressure measurements above an
    instrumented fusion, A cadaveric study", Weinhoffer, Guyer,
    Herbert, Griffith; Spine, Vol 20 No 5, 1995.

    If you have any further questions, please e-mail me.
    Susan L. Weinhoffer

    Hello. In our lab, I have worked on taking IVD measurements from cadaver
    specimens for the past two years. If you haven't already seen, I suggest
    you look at the ORS Transactions for 1994 and 1995 and look under my name.
    This will summarize the work we've been doing. In terms of a pressure
    sensor, we purchased ours from Precision Measurement Co in Ann Arbor, MI.
    The phone number is (313) 995-0041. There is also another company called
    Medical Measurements Incorporated in Hackensack, NJ that we checked into.
    They sell microtransducer catheters and the number is (201) 489-5723.

    If you do not have access to the ORS Transactions, I can send you copies
    via email. Also, I suggest you look at the work of Adams and Hutton as well
    as Nachemson. If you have any questions, feel free to contact me.

    Dear Hani:

    On page 10 - 12 of White and Punjabi's Clinical Biomechanics of the Spine
    you will find a great review of this type work. In particular 3 papers in
    which Nachemson and Morris measure IVD pressure via the nucleus. These are
    all old papers and technology has changed alot, but they should be good
    jumping off points. Hope this helps.


    -Nachemson A: Lumbar Interdiscal Pressure. Acta Orthop.Scand., 37:177, 1966
    -Nachemson A: The Load on Lumbar Discs in Different Positions of the Body.
    Clin. Orthop., 45:107, 1966
    -Nachemson A and Morris JM: In Vivo Measurement of Interdiscal Pressure.
    JBJS, 46:1077, 1964


    Hi, You might try contacting Dr Donal McNally who has worked in this field
    recently and may have just the thing. He's in Bristol, UK: via
    Kim Burton, University of Huddersfield, UK

    Dear Hani,

    The person who is the expert now is Donal McNally, University of
    Bristol, UK.
    from biomch-l list:
    D.S.McNally@BRISTOL.AC.UK Donal S. McNally

    Ian Stokes
    University of Vermont, Department of Orthopaedics and Rehabil.
    Burlington, VT 05405-0084, USA
    Phone: (+1) 802 656 2250 fax: (+1) 802 656 4247

    My advisor informs me that there are commercial devices
    available for that purpose. He believes that one of the makers
    is Swedish. There have also been several papers written using
    these types of devices. For instance,

    McNally D., Adams M: Spine 17:66-73, 1992

    I believe that this paper has some information, if not the authors
    have used similar devices and described them in other papers.

    Also, Adams, MA and Green, TP have an abstract in the 1994
    Transactions of the Orthopaedic Research Society that may briefly
    discuss such a device.

    Good Luck!

    Mark Miller
    University of Vermont
    Mechanical Engineering
    119 Votey Building
    Burlington, VT 05405


    Interesting concept for studying intervertebral disc pressures, but how are
    controlling for lack of movement, gravity and the loss of fluid that occurs
    to tissue death? In addition, fluid mobilization within the disc will be nil
    as all mechanism of fluid mobility will have ceased.
    Mike Poling, H.B.P.E., M.Sc.(Kin.), C.F.A.
    Canadian Back Institute/Lakehead University
    Thunder Bay, Ontario, Canada

    You might want to contact Steve Arms, MicroStrain Co., in Burlington,
    VT. I used to do some work with him when he was first working on Hall
    Effect sensors. Since that time he has developed (apparently) some 1-2mm
    cylindrical polyamide sensors that measure pressure by hoop stress. Good

    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~
    Kimberly A. Dwyer, M.S. Clinical Mechanics Group
    Dwyer@ME.QueensU.Ca Mechanical Engineering
    Queen's University, Kingston, Canada