Lumbar Spine Osteology and Disk Flashcards
Describe bony make up of lumbar vertebral bodies
Block of trabecular/ spongy bone covered by cortical bone
Function of pedicles in lumbar spine
Transmit tension and bending forces from posterior elements to the vertebral body (e.g. ligaments)
Act as a lever for skeletal muscle
Mammillary process of lumbar vertebra
- On transverse process/ superior articular process
- Where multifidi attach
Pars Interarticularis
- Common site for stress fracture
- Between superior and inferior articular processes
Describe Laminae of lumbar vertebrae
Thick –> Can encroach on spinal cord
Function of spinous processes in lumbar vertebrae
Attachment of ligaments
Orientation of facet surfaces in lumbar vertebrae favors:
Flexion and extension
Superior Facets in lumbar vertebrae
- Concave
- Face medial/ posteromedial
Inferior Facets in lumbar vertebrae
- Convex
- Lateral/ anteriolateral
5th lumbar vertebra
- Body is wedge shaped (greater height anteriorly)
- Shape helps counter anterior sheer
- L5-S1 is a site with increased stress to disc
Lumbar Spondylosis
Degenerative changes
- Facet joints: Osteophytes and joint hypertrophy –> Pressure on ligaments (pain) and stiffness
- Vertebral bodies: Osteophytes
- Intervertebral Disc: Thinning (dehydration), breakdown of annulus and excessive motion of pulposus
**Pain and stiffness
Management of lumbar spondylosis
General: Unload Structures
- Extension loads the bones the most –> Pts will like flexion
- Postural education: Neutral spine/ wherever pt is most comfortable is optimal. This may be some flexion
- Joint mobilization to reduce pain and increase motion
- Traction (manual or mechanical)
- Core stabilization (TA) in functional positions with optimal posture
Non-PT management of lumbar spondylosis
- Facet injection
- Benefit = sxs decrease
- Limit: Temporary; pt doesn’t change dysfunctional movement
- Surgical stabilization –> unpredictable outcomes
Types of lumbar stenosis
Central (central canal) or
Lateral (intervertebral foramen)
Central canal dimensions (normal vs. stenosis)
Normal: 15 to 23 mm
Narrowing: 10-12 mm
–> can compress spinal cord or spinal nerve roots
Signs of lumbar spine stenosis
- Postural adjustments to get comfortable
- Walk with flexed posture
- Pain with lumbar extension (or even neutral)
Symptoms of lumbar spine stenosis
- Radicular ache/ cramp into lower limbs when in extension
- AKA Neurogenic claudication (gets worse the longer pt is in extension)
Diagnosis:
Increase incline on treadmill. This will make pts with stenosis feel better, because they have to lean forward into flexion as incline increases
Lumbar spinal stenosis management
Flexion progression:
- Supine or seated
- Teach patient positions of flexion to work in
Stretch hip flexors:
- Tight hip flexors will –> ant pelvic til –> lumbar extension
- Stretch on plinth - helps isolate hip flexors and keep pts from cheating by extending back
Strengthen core musculature: TA in neutral or flexed
Surgery: Laminectomy
Spondylolysis
- Usually younger population
- Stress fracture in pars interarticularis
- Typically aggravated with extension activities
4 potential causes of spondylolysis
- Mechanical (Excessive extension)
- Congenital
- Traumatic (MVA)
- Pathologic (Osteoporosis, bone mets)
Spondylolysis diagnostic test
Single leg hyperextension test
- Used by other medical providers more than PT
- Metrics are questionable
Test:
- Stand on one leg
- Extend the spine
- Positive: Pt’s sxs are reproduced
Management of spondylolysis
- Avoid extension
- Rest, initially
Brace
Core stability training
Flexibility of hip flexors
Modified movement/ training patterns (after period of rest) - avoid extension
Bracing for spondylolysis
- Boston Brace
- Customized, less mobile - Warm n form
- Temporary
- Make in clinic
- More mobile
Spondylolisthesis
Forward slippage of one superior vertebra as a result of instability caused by BILATERAL defect in pars interarticularis
“scotty dog decapitated”
–> Stress on sacral nerve roots –> leg pain
Spondylolisthesis signs and sxs
- Pain with extreme motion, esp extension
- Pain generally follows belt line
- May be able to palpate step off along spinous process
Spondylolisthesis diagnosis
- L4-5, L5-S1 most common
- Slippage determined by XRay
- 4 Grades, according to percent of shift across vertebra
I. 0-25%
II. 25-50%
III. 50-75%
IV. 75-100%
(III and IV are surgical candidates)
Spondylolisthesis management
- Symptom management (modalities)
- Lumbar core stabilization
- Fusion surgery to prevent further slippage (if grade III or IV)
Lumbar compression fracture
Less common than thoracic compression fx
- Lumbar: Traumatic etiology
- Thoracic: Osteoporosis
Management of Vertebral Fx
- Vertebroplasty or Kyphoplasty
- Flexibility
- Strength (core and lower limbs)
- Function (teach body mechanics)
Vertebroplasty
Cement-like material is injected directly into fractured bone
- Stabilizes fx and provides immediate pain relief in many cases
Kyphoplasty
Includes additional step past vertebroplasty
- Prior to injecting cement-like material, a special balloon is inserted and gently inflated inside the fractured vertebra
- Balloon is removed before cement is places
Goal of extra step is to restore height to the bone –> reducing deformity of spine
Intervertebral Disk
- 20-33% of length of spinal column
- 3 mm thick in cervical spine, 9 mm thick in lumbar spine
Relevance to interbody joints (intervertebral disk, adjacent vertebral bodies, and vertebral endplates)
- When disk dehydrates, facet joints take more pressure
Disk Anatomy - NP
70-90% Water
Type I and II collagen (mostly II)
Loads like a balloon
Disk Anatomy - Annulus fibrosis
- Collagen arranged in concentric rings (laminae)
- Adjacent rings have opposite orientation to each other –> Helps protect NP during rotation
- Role: Tension, keeps NP in place
Disk Anatomy - Vertebral end plate
- Articular cartilage
- Attaches to AF and vertebral body
Intradiscal pressure depends on
- Position and properties of disk
- Applied load
- Under prolonged low level loading, disks exhibit creep (e.g. in sitting) –> Pts get stuck in flexion
Loads to failure will cause endplate fracture before disk rupture
Bending loads include sitting, yard work
Lumbar disk injury
- Inherent to anatomy (mobility vs. stability)
- Common mechanism of injury: Flexion, rotation, and loading
- Posterior-lateral injury to the disk
- Injury to lamella allows nucleus to protrude
Pain with disk injury is due to:
- Pressure on nerve root
2. Chemical irritation (inflammation –> chemical mediators)
Five stages of disk injury
- Fissure
- Protrusion
- Prolapse
- Extrusion
- Sequestration
(pts usually come in with either fissure or protrusion)
Examination of disk injury
- Mckenzie method of examination (movements to assess)
2. Identify aggravating activities
Treatment of disk injury: cut knuckle analogy
- Bend a lot: Won’t heal quickly - need to modify activities to decrease flexion to decrease recovery time
- Need some movement (later in healing) to avoid adhesions
Establish a directional preference for pt’s symptoms – stay out of that position
Treatment of disk injury: Education
Key to success
Role of HEP
Posture modifications
Treatment of disk injury: Extension program
Prone –> Prone on elbows –> Extension in lying (on hands) –> Extension with overpressure (PT holds hips down)
**This is if extension helps pt! Disk bulging laterally could feel worse in extension
