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Thread: New(?) fusionless growth modification technique - titanium clip-screw construct

  1. #1
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    New(?) fusionless growth modification technique - titanium clip-screw construct

    Biomechanics of Spinal Hemiepiphysiodesis for Fusionless Scoliosis Treatment using Titanium Implant

    Coombs, Matthew T.; Glos, David L.; Wall, Eric J.; Kim, Jay; Bylski-Austrow, Donita I.

    Spine., POST ACCEPTANCE, 18 July 2013

    Abstract:

    Study Design. In vitro study of effect of hemiepiphyseal implant on biomechanical properties of porcine thoracic motion segments.

    Objective. Determine whether implantation of a titanium clip-screw construct alters spine biomechanical properties.

    Summary of Background Data. Growth modification is under investigation as a treatment for early adolescent idiopathic scoliosis. Biomechanical property changes due to device implantation are essential to characterize immediate post-operative treatment effects.

    Methods. In vitro biomechanical tests were conducted on 18 thoracic functional spinal units. Specimens were tested before and after implantation of a clip-screw construct in lateral bending, flexion-extension, or axial rotation (n = 6 per loading direction). Pure moments were applied, and range of motion, stiffness, and neutral zone were measured. Axial translations were determined bilaterally.

    Results. Implantation of the clip-screw construct decreased range of motion in lateral bending by 19% (p<0.0003), flexion-extension by 11% (p<0.04), and axial rotation by 8%. Mean stiffness in lateral bending toward and away from the treated side increased 20% (p<0.007) and 33%, respectively. In flexion and extension, mean stiffness increased 10% and 16%, respectively. Treatment decreased the neutral zone in lateral bending toward and away from the instrumented side by 30% (p<0.0003) and 47% (p<0.02). In flexion and extension, neutral zone decreased 20% (p<0.04) and 26% (p<0.007). In axial rotation toward and away from the treated side, mean neutral zone decreased by 22% (p<0.04) and 7%. Range of axial translation decreased on the ipsilateral side by 49% (p<0.001), and increased on the contralateral side by 17%.

    Conclusions. Implantation of a titanium clip-screw construct decreased range of motion by less than one-fifth, increased stiffness by one-third or less, and decreased the neutral zone by less than one-half. Range of axial translation decreased on the instrumented side and increased contralaterally. This study suggests that most of the flexibility of the spine is preserved in the immediate post-operative period after implantation of the spinal hemiepiphyseal construct.

    (C) 2013 by Lippincott Williams & Wilkins
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
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  2. #2
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    In vitro biomechanical tests were conducted on 18 thoracic functional spinal units.
    Did they use cadaver spines? I've seen them use just the spine out of a cadaver when inserting a bunch of artificial discs. Just curious.
    If these "functional spinal units" didn't have scoliosis, then the accuracy of the flexibility test would be flawed. They need to know how this new instrumentation affects the scoliotic spine, not a "normal" spine. Just a thought. I guess they've got to start somewhere.
    Last edited by rohrer01; 08-12-2013 at 01:21 AM.
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  3. #3
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    Yes it's in vitro.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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    That was a duh moment on my part! I actually do know the difference between "in vitro" and "in vivo". (sheepish grin)
    Be happy!
    We don't know what tomorrow brings,
    but we are alive today!

  5. #5
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    Yes I knew you knew. :-)

    I had a "duh" moment on the other thread about whether all spinal fusions were included. Most spinal fusions are not for scoliosis to my knowledge so that article may or may not apply here.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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