This is a brief research paper on artificial spinal disc implants that I wrote for an introductory engineering class that focused on material choice for biomedical implants

1. MEMORANDUM
To: Dr. George T. Wynarsky
Professor, Materials Science and Engineering
Dr. Elizabeth Hildinger
Professor, Technical Communication
From: Samantha Luber
Student, Engineering 100.100.103
Date: October 27, 2009
Subject: A Description of Artificial Spinal Disc
Foreword
You have asked me to research and write a brief technical description of an orthopedic
device. The description will focus on what the device is, what its primary functions are,
and how the functions are preformed. I have chosen artificial spinal discs. This document
gives my response to those instructions.
Summary
An artificial spinal disc is an orthopedic treatment for degenerative disc disease. This
disease, which occurs in aging persons, causes the spinal discs, cartilage cushions that
separate the vertebrae bones, to lose fluid (“Basic Disc Anatomy” 1). As a result of fluid
loss in the spinal disc, vertebrae bones are closer together. This closeness of vertebrae
bones causes several serious and painful health conditions, including instability in the
spine, herniation (a condition in which tissue extends past the normal physical constraints
of the back), growth of osteophytes (bone spurs), and reduction in shock absorbency of
the spinal discs (“Degenerative” 1). Doctors use artificial spinal discs as a treatment for
degenerative disc disease. The most widely used design, the Link SB Charité disc, is
composed of two end plates and a central core, further described in the “Anatomy of the
Charité Spinal Disc” section (“Charité” 1). In surgery, doctors immediately insert the
artificial replacement into the original disc’s position and attach the disc to the vertebrae,
so that it may carry out the functions of the original disc (“Degenerative” 4). Once in
position, the artificial spinal disc maintains a proper distance between the vertebrae,
ensuring that no more degeneration of these bones can occur. Furthermore, the new disc
functions as the replaced disc by serving as a shock absorber and providing spinal
support; thus, the artificial disc replacement treats the adverse conditions of degenerative
disc disease.
Degenerative Disc Disease in the Spinal Discs
Not an uncommon health condition, degenerative disc disease affects the spinal discs in
the vertebrae. Spinal discs are composed of three basic elements: protein, cartilage, and
water. Essential to proper disc function, high water content keeps the spinal disc strong
and flexible while maintaining proper spacing between vertebrae (Gillards 7). An
important part of the vertebrae, spinal discs have three important functions; for instance,
in the event of excessive force exertion on the spine, the disc serves as a shock absorber

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by reducing the impact on fragile spinal structures (“Degenerative” 4). In addition, the
spinal disc serves as padding between vertebrae, preventing erosion from touching
vertebrae. Furthermore, the spinal discs are a pivot point about which the spine can bend
and rotate (Gillards 1). Degenerative disc disease affects both of these important
functions because it causes the spinal disc to lose fluid, a key component to the disc’s
functionality (Traynelis 1). As previously mentioned, a dehydrated spinal disc can result
in several adverse conditions, such as herniation, osteophytes, and loss of the spinal
disc’s ability to perform its functions (“Degenerative” 4). All of these conditions cause
severe back pain.
Anatomy of the Charité Spinal Disc
The Charité Artifical Disc consists of three main parts – two endplates and sliding central
Figure 1 core. Shown in Figure 1, both endplates are
Endplates Titanium Teeth identical and composed of high quality cobalt
chromium alloy. The endplates are attached to
the vertebrae via the anchoring teeth on each
endplate. A titanium coating covers each
Sliding endplate to enhance fixation to the vertebrae
core bone (“Charité” 2). Between the two endplates,
the sliding core is placed. The design of the
central core allows normal movement of the
spinal disc in the back. (“Charite” 3). In general,
the Charité Artifical Disc is intended to mimic
Link SB Charité Artificial Disc the function of the original spinal disc.
The most widely used artificial implant for treating
degenerative disc disease
<http://www.spineuniverse.com/displayarticle.php/article1
245.html>.
Functionality and Use of an Artificial Spinal Disc
An artificial disc treats degenerative disc disease by replacing the original failing spinal
disc and performing all previously mentioned functions a spinal disc. Specifically, the
artificial replacement absorbs impact, supports the spine, and restores disc space, this
important spacing preventing further degeneration of vertebrae. The Charité Artifical
Disc accomplishes these functions through proper placement in the back. In surgery, an
incision is made just below the naval. From the incision, the operating doctor removes the
degenerated disc and inserts the artificial replacement into the original disc’s position
before degeneration occurred. The endplates are pressed into the vertebrae above and
below the disc space, and then the core is inserted between the endplates (“Charité” 4).
Now that the vertebrae are spaced appropriately, no further degeneration from rubbing
vertebrae can occur. By function as the original spinal disc, the artificial replacement
treats degenerative disc disease and prevents further damage.

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References
Gillard, Douglas M., MD. “Basic Disc Anatomy.” ChiroGeek. 2005. 11 Oct. 2009
<http://www.chirogeek.com/ /000_disc_anatomy.htm>.
“Charité Artificial Disc.” Charité Artifical Disc. 2009. 11 Oct. 2009 <http://
www.charitedisc.com/charitedev/international/products.asp>.
"Degenerative Disc Disease - Topic Overview." WebMD - Better information. Better
health.. 13 July 2008. 13 Sep. 2009 <http://www.webmd.com>.
Traynelis, Vincent, and Regis W. Haid Jr., MD. "Spinal Disc Replacement: The
Development of Artificial Discs." Back Pain, Neck Pain, Sciatica - Symptoms
Exercises Treatments Causes. 13 Sep. 2009
<http://www.spineuniverse.com/displayarticle.php/article1245.html>.
I have neither given nor received any unauthorized help on this assignment, not have I
concealed any violation of the Honor Code.