DJD of Spine Flashcards
cartilaginous endplaye
serves as the growth plate for vertebral bodies (like epi plate) frm max thickness at infancy down to 1mm thick avascular layer of hyaline cartilage in adultsq
3 main structures of IV disk
cartilaginous endplates
central nucleus pulposus
peripheral annulus fibrosus
nucleous pulposus
conists of proteoglycan (aggrecan w/ chondroitin sulfate side chains) and h20 matrix held by a network of collagen II and elastin fibers
annulus fibrosis
made of 20 rings (lamellae) of highly organized collagen I fibers that run parallel within the same lamella but perpendicular to the adjacent rings for max tensile strength
annulus fibrosus fux
helps the nucleus pulposus recover its original shape when pressure is removed
what supplies blood to the inner edge of the annulus
2 capillary plexuses–> O2 and nutrients must diffuse ~8mm frm there to the nucleus, making the IVD hypoxic and thus dependent on anaerobic metabolism–>produce lactate–>diffuse to opposite sides of nutrients
innervation of annulus fibrosis
only the outer 1-2mm of annulus are innervated, while the inner annulus and disc are aneural and avascular
what happens in natural aging
decreased water content and decreased proteoglycan content–> disc becomes smaller and less flexible–>increased collagen I content (replacing collagen II)–>nucleus becomes stiffer and less translucent with age
annulus in natural aging
recives more pressure because nucleus is less shock-absorptive–> increased collagen, stiffness–> weaker
two factors involved in natural aging
idiopathic loss of endplate blood supply
non-enzymatic glycation–>formation of AGEs–>make disc glycans more sticky and brittle and increase lamellar collagen fiber crosslinking–> decrease tensile strength, and discal tissue begins to have a distinct shade of brown
when eventually the disc collapses (in natural aging)
compressed unevenly by bone–> “stone in shoe deformity”
deformity in natural aging classified from
1 (normal with strong water signal) to 5 (no water signal)
degeneration
mimics natural aging but at an accelerated rate and usualy with more symptoms
–proposed that premature degeneration begins with injury and micrfx to the endplate, rupture of inner annulus and other genetic and environmental factors
DDD
disc degenerationt hat produces symptomatic pain associated with neovascularization and aforementioned ingrowth of sensory nerves
because disc pressure is weaker (they can grow without compression–>increase nociception from the disc)
the degenerative cascade
internal disc disruption–>disc herniation–>disc generation–>spinal stenosis–>degenerative spondyloisthesis–>degenerative scholiosis
- can skip some steps*
disc herniation
usually fromt hinner postero-lateral corner of the disc during bending with rotation of the spine
when does disc herniation occur
with sudden violent trauma (sports) or (more commonly) with less severe trauma (lifting, bending)
herniated pprtion of the disc may..(3)
- be covered with thin layer of peripheral annulus (protrusion)
- rupture through the full thickness of the annulus and lie under the posterior longitudinal ligament or in directly under the dural sac or nerve root (extrusion)
- lose contact with the original disc; moving away (sequestration)
location of herniation is proportional to
affected nerve root
posterolateral disc herniation usually affects the
traversing (exits one segment below) nerve root ex ) C4-C5,C5
far lateral or foraminal disc herniation usually affects
nerve root above
L4,5–>L4
clinical presentation of disc herniation
radiculal pain (pain along the affected nerve root) patients usually come to clinical leaning to one side (sciatic scoliosis) to avoid pain
cauda equina syndrome
disc compresses S2-S4 on both sides affecting bowel/bladder emergency
symptoms in disc herniation + resolution
usually resolve over 6-8 weeks in 80% of cases
if they fail to resolve or begin to cause weakness or numbness–>surgery (discetomy)
absent patellar reflex
L4
cant lift ankle
L4
can lift ankle but not the big toe
L5 (and 2-4th toe sensation)
ankle reflex
L5
cannot push them down
S1
L4 root exists___L4 pedicle
C2 root exists ___C2 pedicle
under
above
biceps
C5
wrist flexion
C7
wrist extension
C7
fist
C8
spreading hand
T1
disc degeneration usually occurs in
middle aged men in the lumbosacral junction
disc degeneration in motion
change in ROM minimal, but quality of motion is abnormal–spinal instability
pain in disc degeneration
activity related pain: back and buttock–usually when bending forward or getting up frm a forward bent position (catching pain–instability catch)
referred pain- usually in back of prox thigh (does not follow a dermatone because not radicular)
tx of disc degeneration
isnt a satisfactory as disc herniation tx
degenerative spondylolisthesis
slipping of vertebral body, usually forward
listhesis
sublaxation
prolisthesis
foward
retrolisthesis
backward
commonest location and less common location for DS
commonest L4-L5
less common L5-S1
segenerative scoliosis occurs secondary to
listhesis of the degenerated segment + lateral wedging of listhetic vertebra
vertebra in degenerative scholiosis are less likely to be
deformed or abnormally rotated
degenerative scholiosis presents with
axial back pain
reffered pain
spinal stenosis
L4-5 posterolateral disc herniation presents with
difficulty walking on heals
indications for surgery
claudication (pain caused by too littlle blood flow esp during exercise) or radicular pain for at least 3 months
MRI demonstrating stenosis consistent with sx
failure of non op tx
healthy enough to udergo surgery
rarely indicated for fusion in absence of
spondylolisthesis oscularosis
spinal stenosis
when disc degeneration is advanced, spinal motion segments try to restabilize by forming osteophytes around the collapsed disc’s margins and facet joints–>hypertrophy–>occlude the spinal canal (stenosis)–> nerve compression–>symptoms
main cause of spianl stenosis is
neurogenic claudication
neurogenic claudication
pain ppt by standing or walking for a short duration and that can be delayed by bending forward on a shopping card/walker
vascular claudication
muscle pain after activity secondary to ischemia where standing (stopping activity) will relieve pain
tx of spinal stenosis
conservative- epidural steroid injection and rarely decompression lamectomy
lumbar disc herniation common in
young adults`
degenerative spondylisthesis commonly seen in
female population
degenerative scholisosis is typically caused by
lateral listehsis and wedging
L4-5 degenerative spondyliolisthesis causing radicular pain due to foraminal stensosis typically follows
L4 dermatome
C4-5 disc herniation cuasing radicular pain typically follows
C5 dermatome
after failed non-op treatment, acute lumbad disc herniation in the young patient, causing radicular leg painw ith minimal back pain should be treated with
decompression-laminectomy only
