Intervertebral Disc Flashcards
Nucleus Pulposus is composed of?
70-90% water which allows deformation under pressure
15-20% type II collagen
65% dry weight is proteoglycans
Annulus fibrosis is composed of?
60-70% water
50-60% of dry weight collage is type I which is found in ligaments and tendons to withstand tensile forces
20% dry weight is proteoglycans
What do the lamellae of the annulus function for?
sheets of rings that resist distraction, shear, torsional stress, posterior fibers are thinner but put together tightly to allow flexion
How does the nucleus move?
the nucleus and annulus move together as a unit like gel surrounded by spaghetti
Annulus fibrosis is innervated by?
the recurrent sinuvertebral nerve which supplies the disc at its level and the level above
Sinuvertebral nerve supplies what 3 structures?
the outer 1/3 of the disc, PLL, and dura mater
Free nerve endings serve to what
pain and proprioceptive function
Vertebral end-plates serve to?
hold the disc in place; the nucleus is well contained by inner annulus and vertebral endplate
Sharpy’s fibers are what?
annulus fibers that insert on vertebral bodies
What are pain generators in the disc?
The end plate and outer annulus are highly innervated which can cause pain with injury
3 functions of Intervertebral Disc?
- transmit loads form one vertebral body to the next
- allow movement between the vertebral bodies
- other function; proprioception
Proprioceptive function of disc and injury theory….
distortion of the disc gives rise to a measurable electrical discharge and electrical stimulation of the outer annulus led to discreet contraction of the multifidus….. so deteriorated discs can lead to segmental instability from motor control loss and wasting of multifidus
Normal disc nuclear movement and tensile forces
compression and distraction
pathological nuclear movement and tensile forces
rotation and shear
Events of disc during compression (7)
- vertebral bodies approximate
- nucleus deforms
- pressure on annulus and endplates (pressure equilibrium between nucleus and endplate prevents too much bulging)
- radial bulging and end plate bulging
- resistance from annulus and trabecular bone of vertebral bodies
- equilibrium and load transfer from body to body
- people with osteoporosis cannot accept WB activity as well from compromised vertebral bodies
The inter body joint is the?
principle WB component of the LS
Distraction of disc and pain indicates?
all fibers of annulus are stressed so pain can indicate tear of annulus, facet jt problem, or ligament tear
Movement that is most detrimental to the disc?
Lateral shearing from rotation of the spine with lifting and twisting
People with posterior herniations will what movement?
Rock forward or be partially flexed to remove some pressure off of posterior nucleus
disc is what kind of a structure
avascular
How does disc get nutrients?
the end plate, outer 1/3 of annulus receive blood and nutrition from bone marrow and spinal arteries, most of the disc is avascular though and starts to degenerate by age 30
What is the best way to regenerate the annulus?
rotation thru modified tension in line of stress without load
Best way to regenerate nucleus?
intermittent compression and decompression
3 things that happen with disc degeneration
- disc integrity decreases with age
- decreased ability to retain water “dry out”
- ability to distribute load across disc changes
4 reasons for degeneration of disc
- biochemical changes
- nutrition deprivation form disrupted diffusion
- mechanics
- genetics
4 Biochemical changes
- decreased rate of proteoglycan synthesis reduces water content
- increased content of collagen/ change in collagen of annulus from type 1 to type 2
- dead cell build and lysosomes disrupt protein sugar bonds to weaken collagen
- amyloid causes degeneration in intervertebral disc
3 causes of nutrition deprivation
- biochemical changes and lack of movement decrease nutrition
- decrease fluid transport decreases nutrition
- injury and trauma
to avoid mechanical degeneration of disc….
avoid shear forces and use postural changes to de load disc
genetically a person might have
bad collagen in disc that affects the shock absorbing properties
DDD presentation
males in 40s and 50s
jobs with lifting, sitting, or history of contact sport/overuse
Pain with DDD will be
constant or intermittent with low grade ache, rarely leg symptoms, morning stiffness from hydrated discs being in a prolonged position
Aggravating factors of DDD
extension and flexion pain with end range, bending, sitting, sit to stand, sustained postures, sudden motions will be bothersome
history of DDD
may include repeated micro trauma or one significant trauma to disc with Insidious or GRADUAL onset
Objectively DDD patients will suffer ROM deficits of and movement impairment of?
ROM: acute episodes will have pain with flexion and extension pain with OP and sustained movements or returning to neutral
might notice excessive extension or rotation
DDD objective testing SLR will be what, skin will be what, segmental motion will be what, imaging may show what?
SLR will be negative, skin will not be easily rolled altered texture, PA’s of segments may be increased or decreased with minimal pain, imaging may show bone spur or disc degeneration, sclerosis of facets and vertebral margins
Goals for DDD include 6
decrease compression, promote nutrition, improve mobility, strengthen core, minimize faulty movements, promote function
Interventions for DDD 4
- unload disc with traction
- educate patient on good body mechanics through lifting instruction, sleeping, posture, agg factors etc.
- joint mobes like centrals, and rotations
- there ex including relative flexibility, exercises to limit habitual motions like extension and disc dehydration exercises
Disc rehydration exercises
pt in unloaded 90/90 with minimal muscle activity to allow diffusion of nutrients for 15-20 minutes; advise exercise in morning when pt’s discs are most hydrated
what exercises position should be avoided in DDD pts?
prone extension exercises, quadruped exercises gain same amount of strength
Disc herniations 4 types
- intra spongy herniation refers to break in endplate
- protrusion or contained herniation
- prolapse/extrusion
- sequestration
Intra spongy herniations may have what nodes, more common where, is painful if nucleus gets where, what age, weakest where?
inflammatory response causes holes in vertebral bodies called Schmorl’s nodes, more common in thoracic than lumbar spine, painful if nucleus gets inside vertebral body, common in late teens early 20s, endplate is weakest between bodies and disc
In a disc protrusion the nucleus migrates where and causes pressure on what?
outward through tear but does not escape outer AF or PLL, pressure on PLL, dura mater, nerve root, may refer pain to butt
clinical presentation of of DH
20-50 y/o after 55 the nucleus is dried out and can no longer herniate, poorly localized ache in back, buttock pain, pain in AM, attempts to unload spine like sit to stand will be painful, history of sudden onset of localized back pain resolved with continued activity followed by intensified pain are larger area
disc herniation pt will have what deviation and what type of pain and what motion will hurt
lateral shift away from painful side, radicular pain, flexion will hurt from stress on outer 1/3 annulus
posterolateral disc herniations will have protective scoliosis shift to which side?
opposite side of lateral nerve root bulge; its the most common
posteromedial disc herniations will have protective scoliosis to which side
shift same side as bulge medial to nerve root; less common
clinical presentation of PL disc herniations; what age; what kind of pain; what aggravates them; what eases their pain?
age 20-55; low back pain, back and leg pain; spasm; aggravated by flexion, sitting, sit to stand, walking, sneeze/cough; eased by lying down or unloading
Screen for caudal equina syndrome by looking for
severe back pain with leg pain, positive SLR, B/B dysfunction
History of PL herniations
sudden onset but usually due to repetitive bending, lifting or frequent lifting activities, episodes are recurrent
Observations of a PL herniation; what posture; what will they avoid; test in what position and for what?
slightly flexed posture, maybe lateral shift, may not want to sit, limited ROM guarded movement, repeated testing in prone for extension to look for centralization of symptoms coming towards the spine
Acute goals of PL herniations (6)
decrease inflammation and muscle guarding,
- protect disc
- centralize pain
- correct shift if present
- decrease compressive forces and tension on nerves
- promote pain free mobility/activity
subactue/chronic goals of PL herniations (6)
- protect disc
- centralize pain
- promote healing
- address faulty movements
- increase mobility relative flexibility
- instructions on return to function and work activity
Mckenzie protocol is indicated for PL herniations except when?
when s/s go to legs
other interventions for P/L herniations (7)
- traction intermittent
- patient education of body mechanics avoid flexion, prolonged sitting, lumbar roll
- joint moves like central PA and rotations
- lumbar support or roll
- activation of deep muscles
- instructions about movement
- epidurals/steroids/surgery
other treatment suggestions
use 90/90 position for comfort, don’t force movements, supports, abdominal bracing, avoid sitting, body mechanics and posture, avoid lifting and bending, unloading, modalities, traction, gentle active motions
Explain left lateral shift
shoulders will be left of the hips in order to relieve pressure off of the lesion on the right side
shift correction involves
identifying the direction of shift, then pulling hips under shoulders to correct it and doing reps of that; Be aware of increasing peripheral symptoms
unload the spine by (3 positions shown)
90/90 supine, leaning in flexion hands on table while standing, chair dips
exercises for discs
trunk rotations, postural changes in extension, focus on hip motions and limiting spine, WALKING provides gentle compression and decompression with rotation from pelvis
Facts about discs 3
- with pure compression, vertebral bodies and endplate will fracture before the disc is damaged
- the lumbosacral joint is the most frequent site of disc degeneration L5/S1
- about 90% of disc herniations occur at L4/L5 with involvement of L5 nerve root or L5/S1 with involvement of S1 nerve root
