5. Intervertebral Discs
Intervertebral Discs
23 narrow spongy shock
absorbers which fit
between the 24
separate bones of your
spine
Each disc has a strong
fibrous outer casing - called
the annulus fibrosus - and a
soft, squashy, jelly-like
interior called the nucleus
pulposus - which is
reinforced with strands of
fibre.
6. Intervertebral Discs
Intervertebral discs have very little in the way
of nerve supply and contain no blood. They
are made up largely of water.
As we get older the amount of fluid in your
discs will diminish.
Although any disc in the entire spine can
prolapse or burst, the most common
ones to which this happens are the
lowest two, that is between the fourth
and fifth lumbar vertebrae and between
the fifth lumbar and the top of the
7. Nucleus Pulposus
Type II collagen strand hydrophilic
proteoglycan
Water content70 ~ 90%
Confine fluid within the annulus
Convert load into tensile strain on
the annular fibers and vertebral
end-plate
8. Annulus Fibrosus
Outer boundary of the disc
More than 60 distinct, concentric
layer of overlapping lamellae of
type I collagen
Fibers are oriented 30-degree angle
to the disc space
Helicoid pattern
Resist tensile, torsional, and radial
stress
Attached to the cartilaginous and
bony end-plate at the periphery of
the vertebra
9. Vital Functions
Restricted intervertebral joint motion
Contribution to stability
Resistence to axial, rotational, and
bending load
Preservation of anatomic relationship
Biochemical Composition
Water : 65 ~ 90% wet wt.
Collagen : 15 ~ 65% dry wt.
Proteoglycan : 10 ~ 60% dry wt.
Other matrix protein : 15 ~ 45% dry wt.
11. Spine Motion Segment
Three joint complex
Intervertebral disc + 2 facet joint
Ligamentous structure, vertebral body
12. Facet Joint
Synovial joint
Rich innervation with sensory nerve fiber
Same pathologic process as other large synovial joint
Load share 18% of the lumbar spine
14. IMAGING
PLAIN X RAY
MRI
CT
MYELOGRAM
DISCOGRAM
ELECTROMYOGRAM
15. Plain Films
Beneficial in determining basic structure, integrity, and
alignment of spinal motion segments
Whether a spinal disorder is acute or chronic can
frequently be determined on plain films
◦ adaptive changes (bony proliferation, endplate remodeling)
Congenital of developmental disorders can be identified
May be of particular benefit in patient under age 20 or
over age 50
In most situations should be initial imaging study
ordered
Routine films include antero-posterior, lateral, and
oblique projections
Specialized views may be additionally ordered
◦ e.g. Coned down lateral view of lumbosacral junction to
evaluate L5-S1 disc space
16. 16
MRI with Gadolinium contrast:
Gadolinium is contrast material allowing enhancement
of intrathecal nerve roots
Utilization:
Assessment of post-operative spine---most frequent use
Identifying tumors / infection within / surrounding spinal cord
Diagnosis of radiculitis
Post-operatively can take 2-6 months for reduction of
mass effect on posterior disc and anterior epidural soft
tissues which can resemble pre-operative
studies
Only indications in immediate post-operative period:
Hemorrhage
Disc infection
18. 18
. Myelogram:
Procedure of injecting contrast material into the
spinal canal with imaging via plain radiographs
versus CT
In past, considered the gold standard for evaluation
of the spinal canal and neurological compression
With potential complications, as well as advent of
MRI and CT, is less utilized:
More common: Headache, nausea / vomiting
Less common: Seizure, pain, neurological change,
anaphylaxis
Myelogram alone is rarely indicated
19. 19
. CT with myelogram:
Can demonstrate much better anatomical detail
than myelogram alone
Utilized for:
Demonstrating anatomical detail in multi-level disease
in pre- operative state
Determining nerve root compression etiology of disc
versus osteophyte
Surgical screening tool if equivocal MRI or CT
20. 20
. Discography (Diagnostic disc injection):
Less utilized as initial diagnostic tool due to high
incidence of false positives as well as advent of
MRI
Utilizations:
Diagnose internal disc derangement with normal MRI / myelo
Determine symptomatic level in multi-level disease
Criteria for response:
Volume of contrast material accepted by the disc, with normals of
0.5 to 1.5 cc
Resistance of disc to injection
Production of pain---MOST SIGNIFICANT
Usually followed by CT to evaluate internal
architecture, but also may utilize MRI
As outcome predictor of those with pain response
received benefit from surgery
52 % of those with structural change received surgical
benefit
23. What is “back pain”?
From the American Academy of
Orthopaedic Surgeons:
It is a loosely defined diagnosis that may refer
to multiple patterns of pain with complex issues
surrounding its diagnosis and treatment. There is a
paucity of evidence from the literature regarding its
cause, management and prognosis. The difficulty
of managing patients with low back pain stems
from the fact that there often is very little
association between physical findings and the
patient’s pain and disability.
24. Causes of Backache
Common causes
• Back muscle sprain
• Prolapsed lumber intervertebral disc
• Obesity
• Poor posture
• Facet joint arthritis
• Unaccustomed activities
• Occupational causes
29. DDx. Age 50 and over
More metastases:
◦ Lung cancer
◦ Breast cancer
◦ Prostate cancer
Spinal stenosis
Rheumatoid diseases
Abdominal aneurysm
Multiple myeloma
31. Lumbar strain or sprain – 77%
Degenerative Disk Disease – 10%
Herniated Disk – 4%
Compression Fracture – 4%
Spinal Stenosis – 3%
Spondylolisthesis – 2%
cancer
infection
32. Additional Categories
. Neuropathic pain
Radiculopathy
. Central Pain States
Spinal stenosis
Radiculopathy: disease of nerve
roots
◦ Radiculitis: inflammation of nerve
roots
◦ Pain, motor and sensory
abnormalities
Plexopathy defined as involvement
of 2 or more roots
33. Risk Factors for Low Back Pain
Gender
◦ Weak association with female sex
◦ Increased risk in pregnancy
◦ Stronger relation to occupation than sex
◦ Sciatica and disc operations more common
in men
Height and weight
◦ Possible increased risk with height
◦ Weak correlation with weight
34. Other Risk Factors for LBP
Smoking
◦ Inhibits metabolic processes in the disc
◦ Weak relation with heavy smoking
Postural deformities
◦ Poor correlation
History of back pain
◦ Increased risk of recurrence
◦ Previous surgery possible factor
Epidural fibrosis
Recurrent disc herniation
Spondylodiscitis
Arachnoiditis
35. Structural Basis of LBP
Largest amount of scientific data
◦ Facet joints
◦ Discogenic pain
◦ Sacroiliac joint
Smallest amount of scientific data
◦ Myofascial pain
◦ Ligament pain
◦ Trigger point pain
37. Waddell’s Signs
Dr. Gordon Waddell is an orthopedic
surgeon from Glasgow, Scotland
Specializes in LBP and its disabilities
Developed tests to help identify LBP
that is non-physiologic or possible
malingering
38. Waddell’s Signs
To aid in assessing functional
(nonorganic) disorders
5 signs:
◦ Tenderness
◦ Simulation (pressure or rotation)
◦ Distraction
◦ Regional disturbance (nonanatomic)
◦ Overreaction
Significant if 3 or more positive
39. Waddell’s Signs
1. Pain on simulated tests for axial
loading – pushing down on the head
2. Pain with passive rotation of the
shoulders and pelvis in the same plane
3. Superficial tenderness
4. Non-dermatomal sensory loss
5. Overreaction during physical exam
6. Straight leg raise that improves with
distraction
7. Non-painful sitting SLR but painful
supine SLR
40. Some Definitions
Sprain – torn or detached ligament
Strain – torn muscle
Radiculopathy – pain & neurological
deficit caused by injury to a nerve root
(radix=root)
Sciatica – pain that radiates down
posterior or lateral leg; a type of
radiculopathy
44. Spinal Stenosis
Local, segmental, or generalized
narrowing of the central spinal canal,
the lateral recesses, or the neural
foramina by bony or soft tissue
elements
Resultant narrowing may encroach
upon the neural structures
45. 45
Spinal Stenosis
Clinical:
CONGENITAL OR DEGENERATIVE
Most common complaint is leg pain limiting walking
Neurogenic / Pseudoclaudication = pain in lower
extremities with gait
Relief can occur with:
stopping activity
sitting, stooping or bending forward
Common are complaints of weakness and numbness of
extremities
Usually becomes symptomatic in 6th decade
46. Spinal Stenosis
Degenerative changes that most
commonly cause stenosis include
osteophytes of the vertebral body
endplates, uncinate processes, or
facet joints and hypertrophy of the
ligamentum flavum and anterior facet
capsule
Initial size of spinal canal important
factor whether degenerative changes
will cause neural impingement or
compression
47. Cervical Stenosis
MRI superior
Can evaluate cervical spine
completely
Can determine accurate size of central
spinal canal
Best predictor of the clinical course of
myelopathic patients has been MRI
studies
◦ higher signal intensity within cord with
decreased cord volume seems to have
poorer prognosis
48. Midline sagittal
diameter less than
12mm considered
relative stenosis.
Diameter less than
10mm considered
absolute stenosis
49. Cervical Root Syndromes
Root Syndromes with Cervical Disc Herniation
Disc Space C4-5 C5-6 C6-7 C7-T1
Root affected C5 C6 C7 C8
Muscles
affected
Deltoid,
supraspinatus
Biceps,
brachioradialis
Triceps, wrist
extensors
Hand
intrinsics,
interossei
Area of pain
and sensory
loss
Shoulder,
anterior arm,
radial forearm
Thumb Thumb, middle
fingers
4th, 5th
fingers
Reflex
affected
Biceps Biceps,
triceps
Triceps Triceps
50. CSS- Myelopathy
Myelopathy – from spinal cord
compression.
◦ The term “myelopathy” refers to pathological
changes of the spinal cord itself.
Pain and sensory changes in the back of
the head, neck, and shoulders.
Performing surgery relatively early
(within 1 year of symptom onset) is
associated with a substantial
improvement in neurologic prognosis
Delay in surgical treatment can result in
permanent impairment
51. CSS - Myelopathy
The goal here is to avoid missing
patients who are myelopathic,
because once stenosis has evolved to
the point that it is compressing (and
causing damage to) the spinal cord,
the progression of symptoms may be
variable…but it is going to progress.
52. T2 weighted MRI, sagittal
view; This patient has
multilevel degenerative
changes of the cervical spine.
The bottom two arrows show
mild stenosis with CSF
(white, fluid signal) still
flowing around the cord.
However, the top arrow is
pointing to the C3/4 level
where there is severe cervical
spinal stenosis, no CSF
around the cord
(compression), and signal
change within the spinal cord
itself (indicating damage).
54. T2- and T1-weighted sagittals at midspine showing spinal canal stenosis
from C4/C5/C6 level
55. Lumbar canal Stenosis
Narrowing of canal increasingly
common
1 per 1000 persons older than 65
years
degeneration of vertebral motion
segment (intervertebral disk and facet
joints
57. Lumbar Spinal Stenosis
Remember that the Spinal Cord ends
at the Conus Medullaris, which is
typically located at the L1/2 interspace
in adults.
◦ L1/2 is the lumbar level least likely to be
affected by Lumbar Spinal Stenosis.
Thus, Lumbar Spinal Stenosis doesn’t
cause myelopathy; when it affects the
motor system, lower motor neuron
signs are what you’ll find.
58. Developmental Lumbar
Stenosis
Growth disturbance of posterior
elements involving pedicles, laminae,
and facet joints
Results in decreased volume of
central spinal canal or neural foramina
Midline sagittal diameter less than
12mm considered relative stenosis
Diameter less than 10mm considered
absolute stenosis
59. Acquired or Secondary
Secondary (acquired) from degenerative
changes, iatrogenic causes, systemic
processes, and trauma.
Degenerative changes - central canal and
lateral recess stenosis from posterior disc
protrusion, zygapophyseal joint and
ligamentum flavum hypertrophy, and
spondylolisthesis
Iatrogenic - surgical procedures such as
laminectomy, fusion, and discectomy.
Systemic processes that may be involved in
secondary stenosis include Paget disease,
fluorosis, acromegaly, neoplasm, and
ankylosing spondylitis
60. Lumbosacral Root Syndromes
Root Syndromes with Lumbar Disc Herniation
Disc Space L3-4 L4-5 L5-S1
Root Affected L4 L5 S-1
Muscles
Affected
Quadriceps Peroneal, anterior
tibial, extensor
hallucis longus
Gluteus max,
gastroc, plantar
flexors toes
Area of Pain and
Sensory Loss
Anterior thigh,
medial shin
Big toe,
dorsum foot
Lateral foot,
small toe
Reflex Affected Knee jerk Posterior tibial
(medial hamstring)
Ankle jerk
Straight Leg
Raising
May not
increase pain
Aggravates
pain
Aggravates
pain
61. Foraminal Stenosis
Important cause of radicular
symptoms
If not addressed at surgery, common
cause of failed back surgery
Neural foramen is a canal that
lengthens at level of lumbar spine
62. Foraminal Stenosis
Degenerative ridges off posterolateral
margin of vertebral body endplate
Size and location of ridges determines
operative approach and amount of
bone that needs to be removed to
decompress neural elements
Facet degenerative changes may also
narrow neural foramen
63. Lateral Recess Stenosis
Lateral region is compartmentalized
into entrance zone, mid zone, exit
zone, and far-out stenosis
64. Lateral Recess Stenosis
Lateral recess stenosis (ie, lateral
gutter stenosis, subarticular stenosis,
subpedicular stenosis, foraminal canal
stenosis, intervertebral foramen
stenosis) - narrowing (less than 3-4
mm) between the facet superior
articulating process (SAP) and
posterior vertebral margin - impinge
the nerve root and subsequently elicit
radicular pain.
65. Entrance Zone
The entrance zone - medial to the
pedicle and SAP – stenosis from facet
joint SAP hypertrophy.
Other causes - developmentally short
pedicle and facet joint morphology, as
well as osteophytosis
Disc prolapse anterior to the nerve root
The lumbar nerve root compressed
below SAP retains the same segmental
number as the involved vertebral level
(eg, L5 nerve root is impinged by L5
SAP).
66. Mid Zone
Mid zone extends from the medial to
the lateral pedicle edge. Mid-zone
stenosis arises from osteophytosis
under the pars interarticularis and
bursal or fibrocartilaginous
hypertrophy at a spondylolytic defect
67. Exit Zone
Exit-zone stenosis involves an area
surrounding the foramen and arises
from facet joint hypertrophy and
subluxation, as well as superior disc
margin osteophytosis. Such stenosis
may impinge the exiting spinal nerve
68. Extra-canalicular Stenosis
Far-out (extracanalicular) stenosis
entails compression lateral to the exit
zone
Occurs with far lateral vertebral body
endplate osteophytosis and when the
sacral ala and L5 transverse process
impinge on the L5 spinal nerve
78. Definition
Degenerative Disk Disease – gradual
degeneration of the disk between
vertebrae, due to loss of fluid and tiny
cracks, part of normal aging process
79. Degenerative Disc Disease
(DDD)
Unfortunately, DDD seems to be sort
of a “wastebasket term” that is often
used to describe age-related changes
on MRI, etc.
◦ While these changes are indeed
“degenerative,” this happens as we age
and is not necessarily indicative of any
significant underlying pathology or
condition.
◦ The majority of individuals > 60 will show
some type of degenerative change(s) on
80. DDD
Degeneration of an individual disc
space typically refers to
loss of disc height,
loss of water content,
fibrosis, end plate sclerosis/defects,
osteophyte complexes, etc.
81. Degenerative Disc Disease
Plain films of limited value
◦ associated changes include decreased
disc height, bony sclerosis, gas or
calcification within disc space, and
endplate hyperostosis
MRI and CT provide excellent
delineation of disc herniation
Process that begins in second or third
decade and progresses
83. Intervertebral Disc
Cellular and Biochemical Change
Decrease proteoglycan content
Loss of negative charged proteoglycan side
chain
Water loss within the nucleus pulposus
Decrease hydrostatic property
Loss of disc height
Uneven stress distribution on the annulus
84. Degenerative Disc Disease
On T2 MRI, signal intensity of disc is
related to state of hydration of nucleus
pulposus
Gradual desiccation into more solid
fibrocartilaginous structure with aging
and degeneration
◦ loss of signal intensity
88. Normal Discs
Well hydrated nucleus
◦ Intermediate signal on T1, high signal on T2
Annulus fibrosus
◦ Low signal intensity on all sequences
Posterior margins are mildly concave, or flat in
upper lumbar spine
May be minimally convex at lumbosacral junction
90. Degenerative Disc Disease
Asymptomatic patients of all ages can show
disc abnormalities on MRI
do we differentiate pain generating lesions
from non-pain generators?
92. Vertebral End-Plate
Become thinner and hyalinized
Decrease permeability
Inhibit nucleus metabolism
Disc space narrowing
Osteophyte formation at the end-plate and
annular junction
Marrow change with increased axial
loading
Subluxation and instability
93. Tears of the Annulus
Most of these tears are not visible on MR imaging
Some have granulation tissue and edema, leading to
high intensity on T2 images = High Intensity Zones
(HIZ)
Known pain generators
Usually seen in the posterior annulus of lower lumbar
discs
Globular or horizontal lines of increased dignal
intensity on T2 and post-contrast T1
98. Diffuse Disc Bulge
Symmetric and circumferential bulge more than 2 mm
in all directions
Also called a diffuse annular bulge
This is considered a “normal” finding in the aging
spine
100. Focal Disc Protrusion
Focal, asymmetric extension of disc
The base is broader than any other dimension
Usually asymptomatic
These are contained by the PLL
102. Disc Extrusion
Usually symptomatic
AP diameter is greater than base
Maintains contact with parent disc
Not contained by the PLL
103. Migration - Sequestration
Migration indicates
displacement of disc
materialaway from
the site of extrusion,
Sequestration is
used to indicate that
the displaceddisc
material has lost
completely any
continuity withthe
parent disc
104. Disc Sequestration
Loss of continuity between extruded
disc and parent disc
Usually symptomatic
105. Further Grading
Subjective division into small, moderate or large
◦ Protrusions and extrusions can be measured, but
reliability is questionable
What is happening to neural elements?
◦ Effacement
◦ Compression
◦ Displacement
Note: a small herniation in a small canal may be
more significant than a large herniation in a
spacious canal
106. Location of Disc Abnormalities
Central
Paracentral
Foraminal
Extraforaminal
Anterior
107. Clinical Correlation
1/3 or more of asymptomatic people
have disc abnormalities on MRI
Only 1% of asymptomatic patients
have extrusion on MRI
90% of lumbar disc abnormalities are
central or paracentral
116. SPONDYLOLISTHESIS
Slipping of one vertebra with respect to other.
Types: (Wiltse) congenital
isthmic
degenerative
traumatic
pathologic
post surgical
Usually assosciated with spondylolysis( which is fibrous
cleft within pars interarticularis)
Prevalence : 4% of population
Location : L5-S1 >L4-L5
usually bilateral
117. ISTHMIC TYPE
MC type
Lesion in pars interarticularis
Subtypes : 1.lytic --- fatigue # of pars
interarticularis.
2.intact but elongated P.A
3.acute # of P.A
Separation of two halves of vertebrae
anterior half--- ( body, pedicle &
superior articular facet )
posterior half--- ( lamina & inf articular
facet )
118. CONGENITAL(DYSPLASTIC)
Dysplasia of superior articular facet of sacrum
PATHOLOGIC
Pathologic # or bare softening.
Ex: pagets disease or osteogenisis imperfecta
DEGENERATIVE
Ex: osteo arthritis
Posterior facet joints became unstable and sublocate
TRAUMATIC/POST SURGICAL
Rare.
119. MEYERDING CLASSIFICATION
Lateral X Ray- Measurement of the distance from
the posterior edge of the superior vertebral body to
the posterior edge of the adjacent inferior vertebral
body. Distance is reported as % of the
total superior vertebral body length.
Grade I ----- 0-25%
Grade II ----- 25-50%
Grade III ----- 50-75%
Grade IV ------ 75-100%
>100% ----- spondyloptosis ( vertebra completely
falls off the supporting vertebra)
120. IMAGING FEATURES
X-RAY:
1. LATERAL: Anterior displacement
2. OBLIQUE: Defect in pars interarticularis
In normal vertebra P.I appears like a “scotty dog”
i. If the appearance is that of scotty dog wearing
a
collar , the defect is the isthmus (P.I)
----- Spondylolysis
ii. If the head of the scotty dog is separated from
the
neck ---- Spondylolisthesis
3. AP : Napolean hat sign
125. CT :
•Pars interarticularis defect has to be located at
pedicle level ;has irregular margins & adjacent
sclerosis. (IV disc level = apophyseal joint )
•Elongated AP diameter of spinal canal.
MRI:
•Pars interarticularis defect
•Forward displacement
•Cord signal changes.
126. Facet (Zygapophysial) Joint Pain
Lumbar facet joints recognized as a
source
◦ Facet syndrome: lumbosacral pain with or
without sciatica
◦ Pain after rotary movement or twisting
◦ Low back pain with radiation to thighs and
buttocks
◦ Poor clinical correlation with imaging or
exam
127. Facet Joint Pain
Definitive diagnosis requires diagnostic
blocks
Lumbosacral facet joints - 15 to 45% of
cases of low back pain
Cervical facet joints - 54 to 67% of
cases of neck pain
◦ Common with “whiplash”
Validity, specificity and sensitivity of
diagnostic facet joint nerve blocks are
considered to be strong
137. POSTURE:
The neck has a slight
natural curve, which sits
on top of the two curves in
the middle and lower back.
Correct posture maintains
all three curves and
prevents undue stress and
strain by distributing body
weight evenly
138. STANDING POSTURE
In correct, fully erect posture,
a line dropped from the ear
will go through the tip of the
shoulder, the middle of the
hip, the back of the kneecap
and the front of the
anklebone.
141. SITTING POSTURE
When sitting in any
position, the three
back curves need to
be maintained.
If you cannot sit
without slouching
forward or backward,
you need to support
yourself with hands
and arms or lean
against a wall or
chair back.
152. Traction
Enlarges foramen
Vacuum effect
PLL traction
Relaxation of spasm
Decreases intradiscal pressures up to
30%
153. Chiropractic Care
Most common “alternative medicine”
Up to 30% of back pain sufferers
Manipulation under anesthesia
154. Trigger Point Injections
Myofascial back pain
◦ Responds better to stretching, local
modalities
Used when other treatments fail
Anesthetic +/- steroid
Limit the number of injections
Prolotherapysclerosing agent
◦ No scientific evidence
155. Injection Therapy
Anesthesia plus anti-
inflammatory effect
Epidural injection
◦ Good for nerve root irritation
◦ Unclear in mechanical back
pain
Effective for facet joint
arthropathy, sacroiliac
disease
Radiofrequency dorsal
rhizotomy
156. Braces
Indicated with
fracture, instability
No evidence to
support long term use
Weakening of
postural muscles
Do not really
immobilize
160. Discectomy
the removal of a
herniated disk to
relieve pressure on a
nerve root
Window in the lamina-
retract nerve-removal
of herniated disc
material-healing by
scar tissue
- Fenestration discectomy
- Endoscopic discectomy
161. Laminectomy
derived from lumber
(lower spine), lamina
(part of the spinal
canal's bony
structure) and -
ectomy (removal).
The operation is
performed to relieve
pressure on one or
more spinal nerve
roots
166. Prior Disc Surgery
If persistent or recurrent symptoms,
MRI exam is optimal method to detect
presence of discal abnormality
Specificity limited in first six months
after surgery
Routinely performed with and without
contrast
◦ enhancement of fibrotic material will be
pheripheraly
167. Treatment Failures
Failure to respond to conservative
measures (6 weeks)
Progression to involve radiculopathy
Rapidly progressive neurologic
symptoms
Chronic pain (> 12 weeks)
168. Failed Back Syndrome
Present with variety of post-operative
findings
Epidural fibrosus
Recurrent disc herniation
Osseus regrowth (stenosis)
Foraminal stenosis
Status of fusion
Infection
169. Fusion itself can accelerate the severity of adjacent level
degeneration as compared with non-fusion.
But there was no correlation in the incidence of
symptomatic adjacent segment diseases according to the
fusion in single level anterior cervical arthrodesis for the
degenerative cervical diseases.
Adjacent segment disease is more a result of the natural
history.