Dr. Raskin is on the voluntary faculty at Jackson Memorial
Hospital and is a Clinical Associate Professor of Radiology at
the University of Miami School of Medicine. He is a practicing
diagnostic radiologist at University Medical Center in Tamarac,
FL. He is also a member of the editorial board of this
The abnormal interpretation of an MRI scan of the spine is often
the reason why a personal injury attorney will pursue a claim
against the defendant in a motor vehicle accident or a slip and
fall injury. The wording of the report can have significant legal
implications. Confusing, ambiguous terminology in describing the
disc can lead to significant unwarranted settlements or jury
verdicts. The interpreting radiologist should be cognizant of the
implications of an "abnormal" finding.
Inconsistencies between subjective complaints and
objective diagnostic tests
Asymptomatic individuals with "abnormal" MRI--Recent literature
has shown that many anatomical abnormalities of the back, including
disc bulges and disc herniations, are quite common in people
without back pain.
Even prior to magnetic resonance imaging (MRI), the high incidence
of disc abnormalities in the lumbar spine of asymptomatic
individuals was quite well known. In 1956, a study using postmortem
examinations of the entire spine showed a 39% prevalence of
posterior disc protrusions.
In 1968, a study using myelography in 300 asymptomatic individuals
demonstrated lumbar disc abnormalities in 24%.
Using computed tomography (CT), a 1984 study reported the
prevalence of herniated discs in asymptomatic individuals to be 20%
in those under the age of 40 years and 27% in those over the age of
Since MRI became a clinically available diagnostic imaging tool in
the mid 1980s, multiple studies have confirmed that more than half
of adults without symptoms have significant disc bulges or disc
Furthermore, the prevalence of disc herniations increases with
Symptomatic individuals with "normal" MRI--This is a difficult
category to properly assess, since back pain is so common,
affecting nearly half of all adults during a given year.
Furthermore, over two-thirds of adults have back pain at some time
in their lives.
Back pain is the leading cause of work-related disability and the
second leading reason for physician visits in the United
Symptomatic individuals with "abnormal" MRI--By far, this group
is the most difficult of all to evaluate and assess properly. The
high prevalence of anatomical abnormalities in individuals without
symptoms, combined with the high prevalence of back symptoms in
adults, makes the likelihood of coincidental findings quite high.
Since more than half of asymptomatic individuals have disc
abnormalities consisting of either significant disc bulges or disc
herniations, it is not unreasonable to assume that more than half
of the individuals involved in motor vehicle accidents or slip and
falls will also have abnormal discs unrelated to their "accident."
The real question that needs to be answered is, can we attribute
the findings seen on an MRI scan to a particular accident or event?
The question is not merely rhetorical, as it has grave financial
implications in our litigious society. With further improvements in
resolution of MRI scans, more and smaller abnormalities are
detected, even though these findings may not be clinically
Myths about neck and low back pain
If you have a disc herniation, you must have surgery--Most disc
herniations get better on their own. Surgery would rarely be
indicated for a disc bulge. Surgery rates for back pain in the
United States are five times more common than in England and more
than twice that in Scandinavia. Surgery for patients whose back
pain is associated only with an abnormal imaging study without
objective clinical findings may be unnecessary, as well as
detrimental to the patient. Some patients with back pain become
worse after surgery. Complicating this situation even more is the
fact that most patients with acute low back pain get better
regardless of differing treatments.
MRI scans can always identify the cause of pain--Most MRI scans
in patients with pain reveal a normal MRI scan or abnormalities on
the MRI scan that are not correlated to the pain.
If your back hurts, you should take it easy until the pain goes
away--Studies have shown that those who remain active despite acute
pain, experience less pain lasting >=3 months.
Most back pain is caused by injuries or heavy lifting--This is
not true. Most back pain occurs without any evidence of related
injury. Up to 85% of patients with low back pain are left without a
definitive diagnosis for their pain. Most patients cannot recall
any specific incident that caused their pain. Injuries or heavy
lifting, although risk factors, do not account for most episodes.
Back pain can be caused by being overweight or by stress. Physical
activity resulting in muscle soreness can result in some back pain,
as does the natural wear and tear that occurs with age. Simply put,
we do not know the cause of most back pain.
Back pain is usually disabling--Studies have shown that it is
often more useful to have patients with back pain return to some
form of light work as quickly as possible. Those that do so
experience less long-term pain than those who rested and waited for
the pain to diminish. In most individuals, the pain will get better
on its own.
Everyone with back pain should have x-rays of the spine--X-rays
are negative in most individuals with back pain. Other than ruling
out rare congenital abnormalities, infections, fractures, rare
forms of arthritis, or neoplasms, the spine x-ray has little or no
effect on treatment.
Bedrest is the mainstay of therapy--This was the standard
therapy until about 10 years ago. This has never been shown to be
effective. Resuming normal activities as much as possible may be
the best option for patients with acute back pain.
Loss of the normal lordotic curve is indicative of muscle spasm
in the neck--It is not unusual to see a radiology report that
states, "loss of the normal lordotic curve, compatible with muscle
spasm," in a patient involved in a motor vehicle accident. The
curvature of the neck vertebrae is usually assumed to be lordotic.
Lordosis refers to the anterior concavity and the curvature of the
cervical spine as viewed from the side. When there is "loss" of the
normal lordotic curve of the cervical spine, this is often referred
to as "straightening" of the normal lordotic curve. It has been
suggested that spasm of the muscles are the cause of loss of the
normal lordotic curve. In a recent study, the cervical curvature of
488 patients with "acute whiplash injury" were compared to the
cervical curve in 495 healthy asymptomatic controls. It was
reported that there was no significant differences in the neck
curvature between the groups and there was no significant
association between clinical symptoms and the curvature of the
This study raises serious questions about the importance of the
"normal lordotic curve" as a marker of clinical importance.
Basically, the intervertebral disc is comprised of two parts:
the outer part and the inner part. The outer part is called the
annulus fibrosus and is composed of up to 90 layers of laminated,
interdigitating collagen fibers that are at approximately a 30š
bias. The annulus fibrosus is thick and fibrous and its purpose is
to contain the inner portion of the disc. This inner portion is
gelatinous and is called the nucleus pulposus. The purpose of this
portion of the disc is to act as a shock absorber. This is the
portion of the disc that herniates when there is a tear or rent in
the annulus. With increasing age, the integrity of the annulus is
compromised and the gelatinous nucleus pulposus starts to lose
water and desiccate. Initially, the nucleus pulposus is comprised
of approximately 80% water, but a desiccated disc may contain ¾60%
water. Therefore, with increasing age, there is less disc to
herniate and traumatic disc herniations are less frequent.
The term "herniation" is a catchall term that has been used to
describe a wide spectrum of disc abnormalities extending beyond the
interspace. We need to strive to use morphological terms that can
be more defined precisely to avoid confusion. The American Spine
Society has suggested the following morphological terms when
describing the disc:
Normal disc--The margins of the disc do not extend beyond the
Disc bulge--A circumferential symmetrical extension of the disc
that extends beyond the interspace.
Disc protrusion--Focal or asymmetrical extension of the disc
beyond the interspace with the base against the disc of origin
being broader than any other dimension.
Extruded disc--A more pronounced extension of the disc beyond
the interspace with the base against the disc of origin being
narrower than the diameter of the extruding material itself.
Sequestered disc--The extruded disc no longer has a connection
between the disc material and the disc of origin. This is also
called a free disc fragment.
Significance of MRI findings
Dating the time of a disc herniation--An MRI scan, by itself,
cannot date the time of occurrence of disc bulge or disc
herniation. The MRI scan merely shows that a disc herniation is
present at the time of the MRI scan.
Most lumbar disc herniations are degenerative--Disc herniations
occur with increasing frequency with age and are frequently present
in asymptomatic individuals. Disc bulges are part of a degenerative
process and not related to a single traumatic event.
Significance of bony changes--Bony changes often take the form
of spondylosis or facet arthropathy. The bony changes seen on an
MRI scan take years to develop and are often in response to, and as
a consequence of, disc degeneration and even disc herniation. Since
the bony changes take years to develop, if they are seen in
association with a disc abnormality at the same level, it is more
likely that all of the findings seen are degenerative in nature and
not related to recent trauma. This does not mean that a disc
herniation cannot occur from trauma, but merely that when a disc
herniation is accompanied by bony degenerative changes at the same
level, the disc herniation is more likely to be a degenerative disc
herniation rather than one related to a recent acute traumatic
Understanding annular tears
--On MRI scans, annular tears are usually evident by a high signal
intensity zone within the posterior fibrous ring of the
intravertebral disc. Previously, these findings were considered to
be predictive of discogenic pain. However, more recent studies have
shown that these high intensity zones are frequently found in
MRI is still the best diagnostic test for determining disc
abnormalities. However, due to the high prevalence of asymptomatic
individuals with abnormalities, combined with the high prevalence
of symptoms, caution should be used in trying to relate a specific
abnormality to a symptom. The inconsistencies between subjective
complaints and the MRI findings must be recognized, as well as the
legal implications of relating an abnormal finding with a
particular accident or event. AR