Natural History of the Aging Natural History of the Aging SpineSpine

Jean-Pierre C. Farcy, MD.Jean-Pierre C. Farcy, MD.

Frank J. Schwab, MD.Frank J. Schwab, MD.

NICE Spine Course 2007

Stages Of Human DevelopmentStages Of Human Development

Importance of the Sagittal PlaneImportance of the Sagittal Plane

•The Thoracic CurveThe Thoracic Curve•The Sacral CurveThe Sacral Curve

Two Structural Curves In Kyphosis

Two Non-Structural Curves In Lordosis

•The Cervical CurveThe Cervical Curve•The Lumbar CurveThe Lumbar Curve

Vary with pelvic / hip posture Vary with pelvic / hip posture stabilized at ambulation agestabilized at ambulation age

Quantified by the Pelvic Incidence Quantified by the Pelvic Incidence (PI)(PI)

Importance of the sagittal Importance of the sagittal planeplane

The four curves in the sagittal The four curves in the sagittal plane endure 16 (4x4) times more plane endure 16 (4x4) times more

resistance to load than possible in resistance to load than possible in a straight spine. a straight spine.

The Spine Range of Motion (ROM)The Spine Range of Motion (ROM)

• 250 degrees between the two 250 degrees between the two extremesextremes– In hyperextensionIn hyperextension– In flexionIn flexion

• Most of the ROM is Most of the ROM is – In theIn the Cervical Spine 105Cervical Spine 105ºº– And in the Lumbar Spine 95And in the Lumbar Spine 95°°

The Spine Range of Motion (ROM)The Spine Range of Motion (ROM)

The PELVISThe PELVIS

• The discovery in Ethiopia by Latimer The discovery in Ethiopia by Latimer of the anthropoid fossil (1974) parts of the anthropoid fossil (1974) parts belonging to “Lucy” substantiates belonging to “Lucy” substantiates the premise that the creature walked the premise that the creature walked upright. Lucy’s pelvis is different upright. Lucy’s pelvis is different from the other semi-erectus from the other semi-erectus creatures and it appears that the creatures and it appears that the differences are crucial to maintain differences are crucial to maintain the standing position permanently. the standing position permanently.

Pelvic Differences in Association Pelvic Differences in Association with Spine Curvatureswith Spine Curvatures

• The permanence of “status erectus” The permanence of “status erectus” requires a modification of the pelvis requires a modification of the pelvis enabling a lumbo-sacral curvature enabling a lumbo-sacral curvature which is only made possible by a which is only made possible by a curvature of the spine above the curvature of the spine above the

pelvis.pelvis.

Pelvic Differences in Association Pelvic Differences in Association with Spine Curvatureswith Spine Curvatures

• Pelvis and spine are so intimately Pelvis and spine are so intimately associated that it is associated that it is impossible to impossible to dissociate spine from the pelvisdissociate spine from the pelvis in any in any study. study.

• Both are intimate structures which Both are intimate structures which function together with the input of loads function together with the input of loads and forces that body mobility requires and forces that body mobility requires insuring the proper balance of the whole insuring the proper balance of the whole body. body.

Chimpanzee. Lucy. Homosapien.Chimpanzee. Lucy. Homosapien.

Relationship Between PI and Relationship Between PI and Lumbar LordosisLumbar Lordosis

• High PI angleHigh PI angle – High lordosis angleHigh lordosis angle– Less vertebrae involved in the lordosis.Less vertebrae involved in the lordosis.– Less rigidity in the SI jointLess rigidity in the SI joint

• Low PI angleLow PI angle– Lower lordosis angle Lower lordosis angle – More vertebrae involved in the lordosis.More vertebrae involved in the lordosis.– More rigidity in the SI jointMore rigidity in the SI joint

Pelvic Incidence

The Spine As A WholeThe Spine As A Whole

• Is a very flexible structureIs a very flexible structure– Multi segments structure Multi segments structure – Division of stress applicationDivision of stress application– Increasing segmental and multisegmental Increasing segmental and multisegmental

stiffness will affect balance.stiffness will affect balance.

• Is a very stable structureIs a very stable structure– Muscle tone, strength and mass insure Muscle tone, strength and mass insure

stabilitystability– Stability depend on them so does balance.Stability depend on them so does balance.

This sketch shows that resistance to loads depends on muscle strength.

Muscle tone of the same muscle groups insure balance.

Loss of muscle mass in aging places the balance system at risk of failure.

The load sharing of the posterior muscles from the spine to pelvis and femoral bone carry the lion’s share.

Schematic of spine and body balanceSchematics of Spine and Body Balance

• DiscsDiscs– Must keep their anatomical integrity. Must keep their anatomical integrity. – Must keep their heights, hydration and Must keep their heights, hydration and

chemical components.chemical components.

• LigamentsLigaments– Must keep their strength and elasticity.Must keep their strength and elasticity.

• BonesBones– Must keep their mineral mass.Must keep their mineral mass.

How to Maintain Good Posture and Good How to Maintain Good Posture and Good BalanceBalance

How to Maintain Good Posture and Good How to Maintain Good Posture and Good BalanceBalance

• Muscle distribution In the backMuscle distribution In the back– From Lumbar spine to pelvisFrom Lumbar spine to pelvis– From Lumbar spine to femoral bone From Lumbar spine to femoral bone

• Muscles strength in the backMuscles strength in the back– Must be sufficient to balance the weight of torso and Must be sufficient to balance the weight of torso and

head.head.

• Muscle toneMuscle tone– Must be tuned to respond all proprioceptive Must be tuned to respond all proprioceptive

commandscommands

• Muscle Mass must be maintained.Muscle Mass must be maintained.

Global AlignmentGlobal Alignment

Stability coneStability cone

• Prof. J. DuboussetProf. J. Dubousset– If center of gravity falls If center of gravity falls

outside the cone then outside the cone then energy consumption energy consumption rises or person must rises or person must seek additional support. seek additional support. (Crutch, Cane …)(Crutch, Cane …)

MorphotypesMorphotypes

• Throughout Darwinian evolution it took Throughout Darwinian evolution it took thousands years for the homo-erectus to thousands years for the homo-erectus to stand and walk erected.stand and walk erected.

• In the course of a human life it takes In the course of a human life it takes months to come from fetus position to months to come from fetus position to erect position and steady walking ability.erect position and steady walking ability.

• The settlement of spine/pelvis define a The settlement of spine/pelvis define a specific morphotype for each individual.specific morphotype for each individual.

The Sacrum Inclination The Sacrum Inclination

Bernhardt M Bridwell KH. Segmental analysis of the sagittal plane alignment of the mormal thoracic and lumbar spines and thoraco lumbar junction. Spine 1989;14:717

End of growth

Disc degeneration begins around age 35

Facet degeneration begins around age 50

Unstable spine

Stable spineankylosis

stenosis spondylo deformity

Most often all together

Progressive Degenerative Process Progressive Degenerative Process

Progressive Degenerative Progressive Degenerative Process Process

• Affects all structures causingAffects all structures causing– The pelvis to gain retro-versionThe pelvis to gain retro-version

• Sacrum sinks and hips move anteriorlySacrum sinks and hips move anteriorly• Hip hyperextension reserve decreasesHip hyperextension reserve decreases• Gravity line moves from behind to front of the hipsGravity line moves from behind to front of the hips

– Lumbar lordosis decreasesLumbar lordosis decreases– Thoracic kyphosis increasesThoracic kyphosis increases

• A vicious circle which can only be A vicious circle which can only be delayed but not stopped.delayed but not stopped.

21-40y Group

41-60y Group

>60y Group

Ag

e

Pelvic Pelvic Parameters:Parameters:

Sacral Slope decreasePelvic Tilt increase

Spinal Spinal Parameters:Parameters:

Global Inclination tilt

forward

GLGLParameters:Parameters:

GL - Heels doesn’t change

Pelvis move backward

Kyphosis increase * Lordosis decrease

Age Related ChangesAge Related Changes

Throughout Human LifeThroughout Human Life

• Irregardless of the position of sacrum and pelvis Irregardless of the position of sacrum and pelvis fromfrom – More verticalMore vertical– More horizontalMore horizontal– The amount of vertebrae included in the lumbar The amount of vertebrae included in the lumbar

lordosislordosis– The angle of lordosisThe angle of lordosis

• A progressive modification of the pelvic version A progressive modification of the pelvic version takes placetakes place– The gravity line moves in front of the hipsThe gravity line moves in front of the hips– The pelvis sinks in retroversion The pelvis sinks in retroversion

The Final Result The Final Result

• Depends upon muscle tone, mass and Depends upon muscle tone, mass and strength to balance the spine delaying the strength to balance the spine delaying the degenerative processdegenerative process

• Genes can influence individual, age-Genes can influence individual, age-related changes.related changes.

• Understanding interactions between Understanding interactions between genes and the environment may delay the genes and the environment may delay the aging process.aging process.

In association with a decreased lordosis

•An increased pelvic tilt

•An increased upper kyphosis

75 years old female

The Degenerative ProcessThe Degenerative Process

Can be smooth, delayed and pain free

in spite of progressive signs of radiological

deformity

75 year old female

The Degenerative ProcessThe Degenerative Process

Can be invalidating and painful

With signs of radiological deformity

ConclusionConclusion

• Short of defining the aging processShort of defining the aging process

• With regard to spine, it affects all With regard to spine, it affects all anatomical elements.anatomical elements.

• It looks like muscles are key in delaying It looks like muscles are key in delaying the aging processthe aging process

• Genes and environment interaction have Genes and environment interaction have certainly a role to play … still to be definedcertainly a role to play … still to be defined