spine biomechanics2

Spine BiomechanicsSpine Biomechanics

Jayant SharmaJayant SharmaM.S.,D.N.B.,M.N.A.M.SM.S.,D.N.B.,M.N.A.M.S..

SpineSpine

Cervical SpineCervical Spine

Seven vertebrae Seven vertebrae – C 1-7C 1-7

More flexibleMore flexible Wide range of motionWide range of motion

– RotationRotation– FlexionFlexion

Peripheral NervesPeripheral Nerves– ArmsArms– Shoulder, Chest and diaphragmShoulder, Chest and diaphragm

Cervical SpineCervical Spine Spinous processes increase in length distallySpinous processes increase in length distally C 1-2 almost transverse, C 1-2 almost transverse, C 2- T 1 --45º to transverseC 2- T 1 --45º to transverse Occipito Atlantoaxial complexOccipito Atlantoaxial complex – – specialized articulation, specialized articulation, large ROM, large ROM, no diskno disk

– 60% axial rotation – C 1-2, 60% axial rotation – C 1-2, – difficult for occipital condyles to slide on C 1, difficult for occipital condyles to slide on C 1, – no loss with agingno loss with aging– Lateral bending – small, alar ligamentLateral bending – small, alar ligament––Inter axial rotation(IAR)-- close to cord, rotate without Inter axial rotation(IAR)-- close to cord, rotate without

impingementimpingement

C 3-7 – flexion -extension predominates, C 3-7 – flexion -extension predominates, lateral bendinglateral bending– IAR – lower vertebra (flex-ex); upper vertebra IAR – lower vertebra (flex-ex); upper vertebra

(lateral bending)(lateral bending)– Distinct coupling pattern – lateral bending & axial Distinct coupling pattern – lateral bending & axial

rotation, rotation, – spinous process point opposite to lateral bendspinous process point opposite to lateral bend– Axial rotation – limited by uncinate processes & Axial rotation – limited by uncinate processes &

facetsfacets Intradural sagittal diameterIntradural sagittal diameter

– 2-3mm lower in extension 2-3mm lower in extension – Posteroinferior margin of upper vertebra & Posteroinferior margin of upper vertebra &

ligamentum flavumligamentum flavum– Cord thicker in extension> less play in extensionCord thicker in extension> less play in extension– Canal widest at C 1-2, narrows at C 5Canal widest at C 1-2, narrows at C 5

Thoracic SpineThoracic Spine

Mid-back or dorsal regionMid-back or dorsal region Ribs attached to vertebrae Ribs attached to vertebrae Relatively immobileRelatively immobile Peripheral nervesPeripheral nerves

– IntercostalIntercostal

Thoracic SpineThoracic Spine Rigid, transition between Cervical & Lumbar Rigid, transition between Cervical & Lumbar

regionsregions Facet orientation changes, may be abrupt T 9-12Facet orientation changes, may be abrupt T 9-12 Flexion-extension – upper: 4º, middle: 6º, lower: Flexion-extension – upper: 4º, middle: 6º, lower:

12º12º Lateral bending – upper: 6º, lower Lateral bending – upper: 6º, lower 2/32/3: : 9º9º Axial rotation – upper Axial rotation – upper 1/21/2: 8º, lower 3 segments: : 8º, lower 3 segments:

2º each2º each Upper & lower region – lateral bending & axial Upper & lower region – lateral bending & axial

rotation strongly coupledrotation strongly coupled Middle – variable coupled motionMiddle – variable coupled motion

Lumbar SpineLumbar Spine

Lower backLower back Carries the the weight of the Carries the the weight of the

upper body upper body – Larger, broader Larger, broader

Peripheral nervesPeripheral nerves– LegsLegs– PelvisPelvis

Lumbar SpineLumbar Spine Flexion-ExtensionFlexion-Extension

– large, due to sizable disks & lack of facet large, due to sizable disks & lack of facet restraintrestraint

– IAR – posterior half of disk, moves with IAR – posterior half of disk, moves with flexion-extensionflexion-extension Centrode – path of moving IARCentrode – path of moving IAR

Lateral bending – IAR on left side of disk Lateral bending – IAR on left side of disk with right bendwith right bend

Axial rotation – IAR in posterior nucleusAxial rotation – IAR in posterior nucleus Disk degeneration – IAR spread outDisk degeneration – IAR spread out

Sagittal plane TranslationSagittal plane Translation– 2-3 mm, normal in symptom free pts2-3 mm, normal in symptom free pts– Up to 5 mm in L 3-4 & L4-5, 4 mm in L5-S1Up to 5 mm in L 3-4 & L4-5, 4 mm in L5-S1

Lateral bending & Axial Rotation couplingLateral bending & Axial Rotation coupling– Spinous processes point in same direction as Spinous processes point in same direction as

lateral bendinglateral bending– Opposite of cervical, upper thoracic, Opposite of cervical, upper thoracic,

lumbosacrallumbosacral

Sacral and Coccygeal regionSacral and Coccygeal region

SSacrumacrum – Triangular structure Triangular structure – Base of the spineBase of the spine– Connects spine to pelvisConnects spine to pelvis– Nerves to pelvic organsNerves to pelvic organs

CoccyxCoccyx– Few small bonesFew small bones– Remnant of tailRemnant of tail

Sacroiliac RegionSacroiliac Region Poorly understoodPoorly understood Partly synovial, partly syndesmoticPartly synovial, partly syndesmotic Stiff, coarse interdigitating articular Stiff, coarse interdigitating articular

surfacessurfaces IAR scatteredIAR scattered Complete ankylosis in up to 76% over age Complete ankylosis in up to 76% over age

of 50of 50 Joint motion – overcome ligamentous Joint motion – overcome ligamentous

resistance, 1 leg stanceresistance, 1 leg stance

General KinematicsGeneral Kinematics CurvatureCurvature

– SagittalSagittal– Shape of vertebrae & disks, rib cage, inclination of Shape of vertebrae & disks, rib cage, inclination of

sacral end platesacral end plate– Developmental phenomenon, posture, rate of growthDevelopmental phenomenon, posture, rate of growth– Add flexibility & shock absorbing capabilityAdd flexibility & shock absorbing capability

6 degrees of freedom6 degrees of freedom– Translation & RotationTranslation & Rotation– 3 orthogonal planes3 orthogonal planes– Motion usually coupledMotion usually coupled

Center of gravityCenter of gravity – in front of 2 – in front of 2ndnd sacral sacral segmentsegment

Types of motionTypes of motion

ROMROM– Facet joints & Intervertebral disksFacet joints & Intervertebral disks– C spineC spine

Flexion-extension predominates, midcervicalFlexion-extension predominates, midcervical Axial rotation, upper cervicalAxial rotation, upper cervical Lateral bendingLateral bending

– T spineT spine Little motion, rib cage.Little motion, rib cage.

– L spineL spine Lateral bending, mid portionLateral bending, mid portion Flexion-extension, lumbosacralFlexion-extension, lumbosacral Rotation, minimalRotation, minimal

– Greater mobility at C & L spine> more stress> Greater mobility at C & L spine> more stress> more clinical complaintsmore clinical complaints

Shear & Tensile CharacteristicsShear & Tensile Characteristics

In direct shear testsIn direct shear tests– Shear stiffness in horizontal directionShear stiffness in horizontal direction

260 N/mm260 N/mm22

Spine rarely fails in pure shearSpine rarely fails in pure shear Similarly under normal physiologic activitiesSimilarly under normal physiologic activities

– Pure tensile loading doesn’t occurPure tensile loading doesn’t occur– But annulus undergoes tensile loading duringBut annulus undergoes tensile loading during

Bending Bending Axial rotationAxial rotation ExtensionExtension

Compressive load characteristicsCompressive load characteristics

Cancellous boneCancellous bone– Large deformationLarge deformation

Up to 9.5% before failureUp to 9.5% before failure Cortical boneCortical bone

– Small deformationSmall deformation Up to 2% before failureUp to 2% before failure

Measurements of In vivo LoadsMeasurements of In vivo Loads

Needle pressure Needle pressure transducer transducer

CalibratedCalibrated– Introduced into Introduced into

nucleus pulpous nucleus pulpous of cadaveric of cadaveric functional unitfunctional unit

Inserted in vivo Inserted in vivo in L3-4 discin L3-4 disc

The Motion SegmentThe Motion Segment Functional Spinal UnitFunctional Spinal Unit

– 2 adjacent vertebrae & intervening soft tissue2 adjacent vertebrae & intervening soft tissue AnteriorAnterior

– Vertebral bodyVertebral body– DiskDisk– ALL, PLLALL, PLL

Support, absorb impact, restrict vertical translationSupport, absorb impact, restrict vertical translation PosteriorPosterior

– Neural arch & its processesNeural arch & its processes– Facet jointFacet joint

Vertebral BodyVertebral Body Primary load-transmitting element, 80-Primary load-transmitting element, 80-

90%90% Bone Mineral Content--Bone Mineral Content-- Osteoporosis> loss Osteoporosis> loss

of horizontal trabeculaeof horizontal trabeculae SizeSize

– Increasing size from C to L spineIncreasing size from C to L spine Compressive load> pressure higher in Compressive load> pressure higher in

center of end plates than peripherycenter of end plates than periphery In vivo, filled with blood> greater In vivo, filled with blood> greater

strength, hydraulic shock absorberstrength, hydraulic shock absorber Weaker anterior trabeculae, Wolff’s lawWeaker anterior trabeculae, Wolff’s law

Posterior ElementsPosterior Elements Pedicles, lamina, facet joints, spinous & Pedicles, lamina, facet joints, spinous &

transverse processestransverse processes Bony processes> lengthen moment arms of Bony processes> lengthen moment arms of

musclesmuscles Forces on processes> transmitted to LaminaForces on processes> transmitted to Lamina Forces on posterior elements> transmitted Forces on posterior elements> transmitted

to vertebral bodies from Pediclesto vertebral bodies from Pedicles Pars InterarticularisPars Interarticularis

– Large bending forces; excessive extensionLarge bending forces; excessive extension– Thicker than rest of laminaThicker than rest of lamina– Common site of stress/fatigue fractures> Common site of stress/fatigue fractures>

weakens motion segment> spondylolithesisweakens motion segment> spondylolithesis

Facet JointsFacet Joints– Major role in controlling motionMajor role in controlling motion– Resist torsion & shear, role in compressionResist torsion & shear, role in compression– Lumbar FSU – facets 40% torque resistence, Lumbar FSU – facets 40% torque resistence,

40% disk, 20% ligaments40% disk, 20% ligaments– Load sharing varies with flexion & extensionLoad sharing varies with flexion & extension

Seated position> decreased lumbar lordosis> Seated position> decreased lumbar lordosis> increased intradiscal pressure & decreased load-increased intradiscal pressure & decreased load-bearing of the facetsbearing of the facets

– Orientation of facetsOrientation of facets C spine - 45º transverse, parallel frontalC spine - 45º transverse, parallel frontal T spine - 60º transverse, 20º frontalT spine - 60º transverse, 20º frontal L spine - 90º transverse, 45º frontalL spine - 90º transverse, 45º frontal

– Capsules lax> allow gliding Capsules lax> allow gliding

LigamentsLigaments Nonsegmental longitudinal (ALL, PLL, Nonsegmental longitudinal (ALL, PLL,

supraspinous)supraspinous) Segmental longitudinal (interspinous, Segmental longitudinal (interspinous,

intertransverse, ligamenta flava)intertransverse, ligamenta flava) Capsular ligamentsCapsular ligaments Limit motion, provide Limit motion, provide

stability/equilibriumstability/equilibrium ALLALL

– Interlinked to disksInterlinked to disks– Resists extensionResists extension– 2X tensile strength of PLL2X tensile strength of PLL

PLLPLL– Narrow over vertebral bodies, flare out over Narrow over vertebral bodies, flare out over

disks; thin lateral extensiondisks; thin lateral extension– Resists flexionResists flexion– Ossification> spinal stenosisOssification> spinal stenosis

Ligamentum FlavumLigamentum Flavum– Elastic & strongElastic & strong– ““shingled” configuration with laminaeshingled” configuration with laminae– Lengthen w/ flexion, shorten w/ extensionLengthen w/ flexion, shorten w/ extension– Loss of disk height or hyperextension> buckle Loss of disk height or hyperextension> buckle

into spinal canalinto spinal canal Interspinous & SupraspinousInterspinous & Supraspinous

– Resist flexionResist flexion– Long moment armsLong moment arms

MECHANISMS OF MECHANISMS OF LIGAMENTOUS INJURYLIGAMENTOUS INJURY

Strain rates appear to Strain rates appear to affect which tissue is affect which tissue is damaged.damaged.

Reports of high Reports of high incidence of ruptured incidence of ruptured interspinous ligamentsinterspinous ligaments

Interspinous ligaments Interspinous ligaments could be injured by could be injured by falling backward and falling backward and applying posterior applying posterior shear forces with the shear forces with the spine flexed.spine flexed.

Forward-bending with a Forward-bending with a flexed spine increases flexed spine increases the shear forces on the the shear forces on the spine because of spine because of stretch of the stretch of the interspinous ligaments interspinous ligaments and the and the superincumbent superincumbent weight.weight.

Extensor muscles that Extensor muscles that can can prevent anterior prevent anterior shearshear on superior on superior vertebrae are silent vertebrae are silent when lumbar spine when lumbar spine flexion is far enough to flexion is far enough to void protection against void protection against shear.shear.

Functional Consideration for the Functional Consideration for the Interspinous andInterspinous andSupraspinous LigamentsSupraspinous Ligaments Supraspinous ligaments are Supraspinous ligaments are

parallel to the compressive parallel to the compressive axis.axis.

Importance of ligaments in Importance of ligaments in resisting flexion appears to resisting flexion appears to be overstated.be overstated.

Supraspinous ligament Supraspinous ligament appears to be appears to be most most importantimportant ligamentous ligamentous restraint to flexion.restraint to flexion.

Interspinous ligamentsInterspinous ligaments are oblique to the are oblique to the compressive axis of the compressive axis of the spine, perhaps providing spine, perhaps providing restraint to flexion restraint to flexion throughout the ROM.throughout the ROM.

Interspinous ligamentsInterspinous ligaments protect against posterior protect against posterior shear forces of the shear forces of the superior vertebra on the superior vertebra on the inferior vertebra.inferior vertebra.

Failure Strength of Spinal LigamentsFailure Strength of Spinal Ligaments

Vertebral MusclesVertebral Muscles Spine buckles with small Spine buckles with small

compressive forces without musclescompressive forces without muscles Anterior, posterior, lateralAnterior, posterior, lateral Gross-function – span several motion Gross-function – span several motion

segssegs Fine-function – span 1 or 2 segsFine-function – span 1 or 2 segs Deep back muscles are major spine Deep back muscles are major spine

movers; many other groupsmovers; many other groups

MultifidiMultifidi Multifidi span only Multifidi span only

a few segments a few segments and run parallel to and run parallel to the compression the compression axis.axis.

There forces only There forces only effect specific areas effect specific areas of the spine.of the spine.

Extensor of the Extensor of the spinespine

Abdominal MusclesAbdominal Muscles

RECTUS ABDOMINISRECTUS ABDOMINIS Major trunk flexorMajor trunk flexor Sections prevent Sections prevent

buckling of muscle buckling of muscle during trunk flexion.during trunk flexion.

Some say no Some say no functional difference in functional difference in upper and lower upper and lower segmentssegments

My next studyMy next study

Special Case of the Quadratus Lumborum and Special Case of the Quadratus Lumborum and Psoas MajorPsoas Major

Psoas major appears Psoas major appears to be primarily a hip to be primarily a hip flexor, with little role flexor, with little role in lumbar in lumbar stabilization.stabilization.

Psoas major Psoas major disperses bending disperses bending stresses across the stresses across the whole lumbar spine whole lumbar spine during hip flexion.during hip flexion.

Special Case of the Quadratus Special Case of the Quadratus Lumborum and Psoas MajorLumborum and Psoas Major

Quadratus Quadratus lumborum lumborum appears to be appears to be important as important as lumbar stabilizer.lumbar stabilizer.

Motion SegmentMotion Segment

Motion of Entire SpineMotion of Entire Spine

Weight bearing properties of Weight bearing properties of motion segment unitmotion segment unit

Compressive Strength of SpineCompressive Strength of Spine

Stress-Strain CurveStress-Strain Curve

Intervertebral DiscIntervertebral Disc

Soft fibro-cartilaginous cushionsSoft fibro-cartilaginous cushions– Between two vertebraBetween two vertebra– Allows some motionAllows some motion– Serve as shock absorbersServe as shock absorbers

Total – 23 discsTotal – 23 discs ¼¼ thth of the spinal column's length of the spinal column's length Avascular Avascular Nutrients diffuse through end platesNutrients diffuse through end plates

Intervertebral Disc AnatomyIntervertebral Disc Anatomy

Spongy center Spongy center – Nucleus Nucleus

pulposuspulposus Surrounded by Surrounded by

a tougher a tougher outer fibrous outer fibrous ring ring – Anulus Anulus

fibrosusfibrosus

Nucleus PulposusNucleus Pulposus

Has more water and PGsHas more water and PGs PG are macro-molecules PG are macro-molecules

– Attract and retain waterAttract and retain water– Hydrophilic gel–like matter Hydrophilic gel–like matter

Resists compressionResists compression Amount of waterAmount of water

– Activity related Activity related – Varies throughout the day Varies throughout the day

Nucleus PulposusNucleus Pulposus– Eccentrically positioned posteriorlyEccentrically positioned posteriorly– Young & healthyYoung & healthy

50% cross-sectional50% cross-sectional 90% water, bound to proteoglycans90% water, bound to proteoglycans

– Aging> dessication> increase viscosity> fissuringAging> dessication> increase viscosity> fissuring– Pascal’s lawPascal’s law

Fluid mass within closed container> local increase in Fluid mass within closed container> local increase in pressure> transmit around entire side wall (annulus)pressure> transmit around entire side wall (annulus)

Young nucleus> even distribution of loadYoung nucleus> even distribution of load Old nucleus> undue concentration on vertebral body Old nucleus> undue concentration on vertebral body

edgesedges– Small displacement w/ ROM, ball-bearing likeSmall displacement w/ ROM, ball-bearing like– Compressive stress predominatesCompressive stress predominates

Anulus FibrosusAnulus Fibrosus

Strong radial tire–like Strong radial tire–like structure structure

Series of lamellaeSeries of lamellae Concentric sheets of collagen Concentric sheets of collagen

fibers fibers – Connected to end platesConnected to end plates– Orientated at various anglesOrientated at various angles– Under compressionUnder compression

Become horizontalBecome horizontal Encloses nucleus pulposusEncloses nucleus pulposus

Annulus FibrosusAnnulus Fibrosus– 90 collagen sheets90 collagen sheets– Fibers of adjacent sheets 30º to each Fibers of adjacent sheets 30º to each

otherother– Hyaline cartilage plates & bony ring Hyaline cartilage plates & bony ring

epiphyses of vertebral bodiesepiphyses of vertebral bodies– Vertical component – tension resistor Vertical component – tension resistor

during flex-ex & lateral bendingduring flex-ex & lateral bending– Horizontal component – rotary stressHorizontal component – rotary stress– Axial load – tensile stressAxial load – tensile stress

AnnulusAnnulus

In Bending In Bending – Increased tensile force posteriorly Increased tensile force posteriorly – Increased compressive force anteriorlyIncreased compressive force anteriorly

In Rotation In Rotation – Reorientation of collagenous fibersReorientation of collagenous fibers– Tightening of fibers traveling in one Tightening of fibers traveling in one

directiondirection– Loosening of fibers traveling in opposite Loosening of fibers traveling in opposite

directiondirection

DiskDisk Major restraint to motionMajor restraint to motion Viscoelastic behavior, demonstrates Creep & Viscoelastic behavior, demonstrates Creep &

HysteresisHysteresis Avascular Avascular

– End-plate microfractures> vascular ingrowth & End-plate microfractures> vascular ingrowth & granulation tissue> altered mechanical behaviorgranulation tissue> altered mechanical behavior

– End-plates influence the nutrition; diffusionEnd-plates influence the nutrition; diffusion Lumbar FSULumbar FSU

– Disk – 40% of torque resistanceDisk – 40% of torque resistance– Rest by posterior element and ligamentsRest by posterior element and ligaments

Diurnal change in heightDiurnal change in height– 1% shorter at night; 2% for children; 0.5% for 1% shorter at night; 2% for children; 0.5% for

elderlyelderly– 50% of height lost during first 2 hours in upright 50% of height lost during first 2 hours in upright

Healthy disks creep slowerHealthy disks creep slower

Intervertebral Disc FunctionsIntervertebral Disc Functions

Movement of fluid within the nucleusMovement of fluid within the nucleus– Allows vertebrae to rock back and forthAllows vertebrae to rock back and forth– FlexibilityFlexibility

Act to pad and maintain the space Act to pad and maintain the space between the twenty-four movable between the twenty-four movable vertebraevertebrae

Act as shock absorbersAct as shock absorbers Allow extension and flexion Allow extension and flexion

Intradiscal PressureIntradiscal Pressure– Compressive loads in vivo: 500N Compressive loads in vivo: 500N

standing, 700N sittingstanding, 700N sitting– Increased to 3000 to 6000N during Increased to 3000 to 6000N during

lifting of moderate weights, decreases lifting of moderate weights, decreases with load closer to bodywith load closer to body

– Estimate of P = 1.5X compressive load Estimate of P = 1.5X compressive load divided by the cross sectional areadivided by the cross sectional area

– Disk pressure is usually uniformDisk pressure is usually uniform– Pressure lowest in supine positionPressure lowest in supine position– Disk usually does not fail, but end plates Disk usually does not fail, but end plates

fracturefracture

Creep CharacteristicsCreep Characteristics

Grade 0 - Non-degenerative disc ( more viscoelastic)Grade 2 – Mild degenerative disc (less sustenance)

Grade 3 – Severe degenerative disc ( more deformation)

Pathology of Intervertebral Disc Pathology of Intervertebral Disc InjuryInjury Annular InjuryAnnular Injury

– Annular rings Annular rings SoftenedSoftened Overstretched Overstretched Torn Torn

– Normal viscoelasticity is exceededNormal viscoelasticity is exceeded– Cannot stabilize or limit motionCannot stabilize or limit motion– Nucleus pulposus exerts pressure on Nucleus pulposus exerts pressure on

weak partweak part– Buckling occurs - Buckling occurs - Disc BulgeDisc Bulge

Pathology of Intervertebral Disc Pathology of Intervertebral Disc InjuryInjury

ExtrusionExtrusion– Fragmentation of Fragmentation of

nucleus pulposusnucleus pulposus– Nuclear material Nuclear material

dissects its way dissects its way through breaches through breaches in annulus fibrosusin annulus fibrosus

Pathology of Intervertebral Disc Pathology of Intervertebral Disc InjuryInjury ProlapsesProlapses

– Fissures provide Fissures provide pathway for pathway for irritating nuclear irritating nuclear fluid to escape fluid to escape onto perineural onto perineural tissue *tissue * Persistent and Persistent and

chronic back painchronic back pain **- - Hampton et alHampton et al

Theory of weight bearingTheory of weight bearing

Nucleus pulpous Nucleus pulpous imbibes waterimbibes water Develops internal pressureDevelops internal pressure Pressure exerted in all directionsPressure exerted in all directions

– Lateral forces Lateral forces Against annulusAgainst annulus

– Superiorly and inferiorly directed forces Superiorly and inferiorly directed forces Against end platesAgainst end plates

– Increases stiffness Increases stiffness Of end plate and annulus fibrosusOf end plate and annulus fibrosus

Sagittal plane translationSagittal plane translation– 2-3 mm, normal in symptom free pts2-3 mm, normal in symptom free pts– Up to 5 mm in L 3-4 & L4-5, 4 mm in L5-S1Up to 5 mm in L 3-4 & L4-5, 4 mm in L5-S1

Lateral bending & axial rotation couplingLateral bending & axial rotation coupling– Spinous processes point in same direction as Spinous processes point in same direction as

lateral bendinglateral bending– Opposite of cervical, upper thoracic, Opposite of cervical, upper thoracic,

lumbosacrallumbosacral

Theory of weight bearing Theory of weight bearing (cont’d)(cont’d)

Mechanical CharacteristicsMechanical Characteristics

Tensile stiffness of the disc annulus in different directionsHighest along – 150

Lowest along – the disc axis

StrengthStrength

Highest – Along normal direction of annulus fibers( 3 times stronger than that along horizontal direction)

Back PainBack Pain

Pain is a protective mechanismPain is a protective mechanism Nerve endings near the spine receive Nerve endings near the spine receive

abnormal stimulation abnormal stimulation Signals are transmitted from affected Signals are transmitted from affected

area to the brainarea to the brain– They are interpreted as painThey are interpreted as pain

A reflex action follows in the backA reflex action follows in the back– Muscles go into spasm Muscles go into spasm

To protect the backTo protect the back To keep the damaged area immobileTo keep the damaged area immobile

Types of painTypes of pain

Based on sourceBased on source– MechanicalMechanical– ChemicalChemical

Based on affected regionBased on affected region– LocalLocal– ReferredReferred

Based on natureBased on nature – TransientTransient– Acute Acute – Chronic Chronic

Causes of LBPCauses of LBP

DysfunctionDysfunction Predisposing factorsPredisposing factors

– Postural stressPostural stress– Work related stressWork related stress– Disuse and loss of mobilityDisuse and loss of mobility– ObesityObesity– Debilitating conditionsDebilitating conditions

Precipitating factorsPrecipitating factors– MisuseMisuse– OveruseOveruse– Abuse or traumaAbuse or trauma

ScoliosisScoliosis

A medio-lateral A medio-lateral curve of the curve of the vertebral columnvertebral column Exceeding 10Exceeding 1000

– TypesTypes Structural Structural NeuromuscularNeuromuscular IdiopathicIdiopathic Non-structuralNon-structural

– TreatmentTreatment ExercisesExercises BracingBracing

Detection of ScoliosisDetection of Scoliosis

LordosisLordosis In the sagittal planeIn the sagittal plane

– ‘‘S’ shapeS’ shape As a small childAs a small child

– When starts to sitWhen starts to sit– Cervical lordosisCervical lordosis

Toddler and adultToddler and adult– When starts to standWhen starts to stand– Lumbar lordosisLumbar lordosis– Allows spring-like actionAllows spring-like action

KyphosisKyphosis An exaggerated curvature in An exaggerated curvature in

the sagittal planethe sagittal plane Long rounded curveLong rounded curve ( (round round

backback)) Sharp posterior angulation Sharp posterior angulation

((hump backhump back)) Possible causesPossible causes

– Wedge compression fractureWedge compression fracture– Ankylosing spondylitisAnkylosing spondylitis– Senile osteoporosisSenile osteoporosis– Destructive tumors of spineDestructive tumors of spine

Intervertebral DiscIntervertebral Disc Intervertebral disk make up 20-30% of Intervertebral disk make up 20-30% of

the height of the column and the height of the column and thickness varies from 3mm in cervical thickness varies from 3mm in cervical region, 5mm in thoracic region to 9 region, 5mm in thoracic region to 9 mm in the lumbar region.mm in the lumbar region.

Ratio between the vertebral body Ratio between the vertebral body height and the disk height will dictate height and the disk height will dictate the mobility between the vertebra –the mobility between the vertebra –– Highest ratio in cervical region allows for Highest ratio in cervical region allows for

motionmotion– Lowest ratio in thoracic region limits Lowest ratio in thoracic region limits

motionmotion

http://www.spinalrehab.com.au/disorders/jb2pre.jpg

Lumbar Foramen

http://www.spineuniverse.com/displayarticle.php/article1973.html


Spinal CordNerve Root


Lateral View Posterior View

RodWire Bar CagePlate Screw

Pedicle Screw

Threaded Cage

Facet Screw

Arthrodesis = surgical fixation of a jointArthrodesis = surgical fixation of a jointStiffer arthrodesis = better healing environment (currently believed)Stiffer arthrodesis = better healing environment (currently believed)

Mechanical Causes

Biological Causes

Stimulating stresses

No slide between bone fusion interface

No separation between bone fusion interface

OsteoinductionBlood supply

Osteoconduction

NOTE: FBI stands for Fusion Bone Interface

Osteoinduction The ability to mediate the induction of osteosis exceptionally in a nonbony location

Osteoconduction The ability to act as a scaffold for new osteosis in a bony environment

Blood supply Provide sufficient nutrition for osteosis Stimulating stresses Bone is laid down where needed and resorbed where not needed Wolff’s lawWolff’s law

Separation at FBI Bone contact surfaces are separated by external load bone non-union

Slide at FBI Bone contact surfaces slide along each other causing by external load bone non-union

Bone To Be Fused Bone FusionBone Fusion

Low Back Pain Low Back Pain DisordersDisorders

Spondylolysis

Spondylolisthesis

What is the CORE?What is the CORE? Lumbo-pelvic-hip complexLumbo-pelvic-hip complex Location of center of gravity (CoG)Location of center of gravity (CoG)

Efficient core allows forEfficient core allows for Maintenance of normal Maintenance of normal length-tension length-tension

relationshipsrelationships Maintenance of normal Maintenance of normal force couplesforce couples Maintenance of optimal arthrokinematicsMaintenance of optimal arthrokinematics Optimal efficiency in entire kinetic chain during Optimal efficiency in entire kinetic chain during

movementmovement Acceleration, deceleration, dynamic stabilizationAcceleration, deceleration, dynamic stabilization

Proximal stability for movement of extremitiesProximal stability for movement of extremities

Core Stabilization Core Stabilization ConceptsConcepts A specific core strengthening program can:A specific core strengthening program can:

IMPROVEIMPROVE dynamic postural control dynamic postural control Ensure Ensure appropriate muscular balanceappropriate muscular balance & & joint joint

arthrokinematicsarthrokinematics in the lumbo-pelvic-hip complex in the lumbo-pelvic-hip complex AllowAllow for expression of for expression of dynamic functional dynamic functional

performanceperformance throughout the entire kinetic chain throughout the entire kinetic chain Increase neuromuscular efficiencyIncrease neuromuscular efficiency throughout the throughout the

entire bodyentire body

Spinal stabilizationSpinal stabilization Must effectively utilize strength, power, neuromuscular Must effectively utilize strength, power, neuromuscular

control & endurance of the “prime movers”control & endurance of the “prime movers” Weak core = decreased force production & efficiency Weak core = decreased force production & efficiency

Protective mechanism for the spineProtective mechanism for the spine Facilitates balanced muscular functioning of the entire Facilitates balanced muscular functioning of the entire

kinetic chainkinetic chain Enhances neuromuscular control to provide a more efficient Enhances neuromuscular control to provide a more efficient

body positioningbody positioning

Core Stabilization Training Core Stabilization Training ProgramProgram

Level I: StabilizationLevel I: Stabilization

Level II: Stabilization and Level II: Stabilization and StrengthStrength

Level III: Integrated Level III: Integrated Stabilization StrengthStabilization Strength

Level IV: Explosive StabilizationLevel IV: Explosive Stabilization

Sciatica Sciatica - radiating pain down the leg- radiating pain down the legRadiculopathyRadiculopathy- radiating pain down the leg as a result of nerve root radiating pain down the leg as a result of nerve root

irritationirritation

Back PainBack Pain irritation of the posterior primary ramus irritation of the posterior primary ramus - facet capsule, local musculature - facet capsule, local musculature sinuvertebral branch - posterior annulus sinuvertebral branch - posterior annulus change in disc loading and shape, biomechanics change in disc loading and shape, biomechanics loss of viscoelasticity. loss of viscoelasticity. 90% of radiating pain have long-standing prior 90% of radiating pain have long-standing prior

episodic low back pain episodic low back pain

Straight-leg raising : L5, S1 rootStraight-leg raising : L5, S1 root Contralateral SLR : sequestrated or extruded Contralateral SLR : sequestrated or extruded

discdisc Femoral stretching, reverse SLR : L3, L4 rootFemoral stretching, reverse SLR : L3, L4 root

Root Tension SignsRoot Tension Signs

Epidural steroid injection Epidural steroid injection

If leg pain persist beyond 4 weeksIf leg pain persist beyond 4 weeks Maximum 3 injection per year Maximum 3 injection per year

Response vary greatly Response vary greatly - Hagen,2002 : short-term effect 40%. no significant- Hagen,2002 : short-term effect 40%. no significant long-term effect long-term effect - Wiesel, 1995 : 82% relief for 1 day, 50% for 2 - Wiesel, 1995 : 82% relief for 1 day, 50% for 2

weeks,weeks, 16% for 2mo. 16% for 2mo. - White 1983 : 77% avoid surgery after injection - White 1983 : 77% avoid surgery after injection - Carette, 2002 : neither significant functional- Carette, 2002 : neither significant functional benefit nor reduction in need forbenefit nor reduction in need for surgerysurgery

Indication of SurgeryIndication of SurgeryIdeal candidateIdeal candidate history, physical examination, radiographic finding, history, physical examination, radiographic finding,

are consistent with one another are consistent with one another when discrepancy exist, the clinical picture should when discrepancy exist, the clinical picture should

serve as the principal guide. serve as the principal guide. Absolute surgical indicationAbsolute surgical indication cauda equina syndromecauda equina syndrome acute urinary retension/incontinence, acute urinary retension/incontinence, saddle anesthesia, back/buttock/leg pain, weakness, saddle anesthesia, back/buttock/leg pain, weakness,

difficulty walkingdifficulty walkingRelative indicationRelative indication progressive weakness progressive weakness no response to conservative treatmentno response to conservative treatment

Facet JointFacet Joint Synovial jointSynovial joint Rich innervation with sensory nerve fiberRich innervation with sensory nerve fiber Same pathologic process as other large synovial jointSame pathologic process as other large synovial joint Load share 18% of the lumbar spineLoad share 18% of the lumbar spine

Vital FunctionsVital Functions Restricted intervertebral joint motionRestricted intervertebral joint motion Contribution to stabilityContribution to stability Resistence to axial, rotational, and Resistence to axial, rotational, and

bending loadbending load Preservation of anatomic relationship Preservation of anatomic relationship

Biochemical CompositionBiochemical Composition Water : 65 ~ 90% wet wt.Water : 65 ~ 90% wet wt. Collagen : 15 ~ 65% dry wt.Collagen : 15 ~ 65% dry wt. Proteoglycan : 10 ~ 60% dry wt.Proteoglycan : 10 ~ 60% dry wt. Other matrix protein : 15 ~ 45% dry wt.Other matrix protein : 15 ~ 45% dry wt.

Vertebral End-PlateVertebral End-Plate Cartilaginous and osseous componentCartilaginous and osseous component Nutritional support for the nucleusNutritional support for the nucleus Passive diffusionPassive diffusion

Neurologic ExaminationNeurologic Examination

spine biomechanics2

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