STRUCTURAL CHANGES IN THE LUMBAR INTERVERTEBRAL DISCS* Their Relationship to Low Back Pain and Sciatica

STRUCTURAL CHANGES Their In recent pain known years manner it degeneration. the pathological which in Some these help in interverteb...
Author: Mervyn Kelly
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STRUCTURAL

CHANGES Their

In

recent

pain

known

years

manner

it

degeneration.

the

pathological

which

in

Some

these

help

in

intervertebral

and

become

in

123

removed

and

the

intervertebral

posterior

discs

vertically.

Pieces

examination. the

anatomical,

these

changes

this

discs,

to

to correlate

the

the

The

vertebrae

exhibit part

all the gross of the

foramen

and

This

united

by

three

the

posterior

nerve

clinical

joints

is

about

the

of the

The

and to

then

histological

information

The

studied low

intervertebral

on

relationship in detail

back

disc are

joints

nerve

posterior

detail.

subjected

to obtain

been

articulations

is occasionally

in

out. then

pain

of

in order

syndrome.

CONSIDERATIONS

: the

the

was carried arches were

occur.

has

the

a preliminary

horizontally

were

that

spine

examining

examined first

possible

picture

of synovial to the

by After

dissection The neural

joints

been

of the

root of

of low little

to be learned

acquired

were

variations

posterior

features relation

relationship

causes clinicians,

necropsies.

divided

PHYSIOLOGICAL

The

is in close

indeed

intimate

were

it has

the

AND

anatomical

capsule

and

with

posteriorly.

common most

still

been

flava

situ

appearance

findings

are joints

has

routine

ligamenta in

pathological

radiographic

ANATOMICAL

zygapophysial

and

and

necropsy

has at

of investigation

physiological

of the by

much

problems

ligaments

method

and

excised

examination

of the

By

one

of the excised spine, a careful ligaments were inspected.

joints

after

CANADA

symptoms.

spines

radiograph of the cadaver and The supraspinous and interspinous

that

DISCS*

Sciatica

is acknowledged

occur,

these

lumbar

and

TORONTO,

clear fact

that

cause

Pain

MACNAB,

this

changes

INTERVERTEBRAL

Back

increasingly

understanding

discs

Low

IAN

Though

changes

LUMBAR

to

HARRIS

has

is disc

about

THE

Relationship

R. I.

back

IN

root

elsewhere

found

the

to the

nerve

The

the

by

is of

attachment

to

two and

anterior

intervertebral

capsule

roots

the

joints

body.

through

bound

to

and

synovial

in the

as it escapes

joints

anteriorly,

simple

adhesions.

great

clinical

significance.

The

detailed

bodies

is

of

subsequently

of

annulus

obliterated These scars

*

Paper

304

read

in

by

London,

is penetrated

nucleus

herniations

Dr Macnab July

the caudal

cartilage

plates

changes at

meeting

three

help

the

blended

and

the

vessels

passing

1929)

(Fig.

discs

the

of the

are

single

disc ; and the

When

growth

they act Up to the

vertebral

these

two

are

the

vertebrae.

from

2).

that a

annulus.

: they

to anchor

spongiosa

into

intervertebral

functions

vertebral

changes

body

vessels

are

interrupts the lamella of calcified cartilage. which may break down under stress, giving

material

may

characteristic

the combined

of the

blood

scar which weak areas vessels

pulposus

surfaces

the

degenerative

intimately

have

and

the

nucleus

(Bohmig

of nuclear

blood

its of

1) ; they

by

pulposus

and

nature

components

vertebral bodies (Fig. the nucleus pulposus

microscopic herniations to some of the structural

World,

and

they leave a striated represent structurally

to microscopic

main

plates,

cranial These

cartilage

and

disc the

three

cartilage the

cartilage.

the

eight,

the

are

hyaline

of the immature barrier” between

into

rise

: the

intervertebral

understanding

There

plales-On

of hyaline

zone as a age

unit

cartilage

plates

of the in

occur.

functional The

anatomy

importance

enter

into

the of an

the

disc ageing

of the Orthopaedic

vertebral

from disc.

the

bodies.

Through

spongiosa

and

Occasionally

Associations

large

of the

these

give

rise

amounts

English-speaking

1952. TIlE

JOURNAL

OF

BONE

AND

JOINT

SURGERY

STRUCTURAL

of

nuclear

material

loss

of nuclear

This The

;,uclt’zis

vater

to

a large

of a loose

a few

cells

plays an intercellular

through

nucleus hvgroscopic

extent

on

these

role

and

disc The

(Schmorl’s

irregularly feature

is a viscid

function

material nutrition ma play

disc. in

has

in the

‘hole

pulposus of which

of intercellular l)ut

With

a

meshes

amount

a high

as

nucleus

understood,

of the a part

It disc

the

large

is poorly

gel.

of the

arranged, is the

nodes).

joint.

Histologically

strands

the this

facilitating

ill

growing

30:-

1)ISCS l)lates

of the

1948).

A striking

intercellular

decreases

cartilage

properties.

fibrous

of the

the

mechanics

in the

physical

of fine

INTERVERTEBRAL

in

the

(Macnab

morphology.

function

important substance

with

pulposus

is very network

LUMBAR

defects

interferes

of variable

The

5u1)stanCe.

THE

IN

escape

pit/posits-The and

consists are

may substance

content

depends

CHANGES

it

prol)al)ly

increasing age the degenerative

initiatillg

the

changes. i’/ze

aiz;iulus

The

annulu5

is

fibrosus-There

consists

of

no

sharp

lamellae

of

dividing

coarse

line

collagen

between fibres

the

nucleus

running

;ul

ol)liqueh’

;Lllnulus.

between

the

p.

C

-!.



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.

.

.

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11G.

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Figure coluiiinar liiiibar

arrangenent vertebra of

vertebral in

l)Odies.

the

the

annulus

alid

the

fibres one

The

occurs

the

vertebral W’hen

l)On\’ the the

observation \‘OL.

36B,

13(4)

annulus margins, spinal

has NO.

2,

to which

they

are

form

ring

rise

MAY

1954

three

and

enters with are

the the

deeply the

the

statement

that

so

the

doing

sul)jected.

groups.

One

vertebral

a

firm

that

into

l)lte

by

fan

from

their

stream

about to

the

nucleus pulposus

three

alignment

year.

millimetres (Beadle

possesses

the

ligaments; ring

pulposus

of

to meet

sixteenth

l)one

to

attachment

spinal

peripheral

the

able fibres ol)liquelv

the

downwards

the

about

in

‘ ‘

longitudinal

hone the

out

curves

above

nucleus

of the

hi’aline



chaliges

l)etter

the

at

anchorage the

attachment

the

body body

longitudinally

The

ful)res

are

fibres

group with

of the

hl)res

librosus

to blend vertebral

direction the

The into

annulus

imhedded disc

is divided to

vessels.

deeply

of the

outwards

fuses

column

given

into

giving

in a newborn child s1ioving the of a growing cpiphvsis. Figure 2 Fourth perforations of tln cartilage l)lat(’ for the

is of interest.

be folloved fibres

jasses

fibres this

plate

The

group

UJ)wards

turns

1)eripheral

by

2

plate

be shown

can

and

can

3).

and

one

it preselit,

cartilage

(Fig.

phtte

below;

group

this

hyaline

cells

cartilage from

stresses

of attachnient

cartilage

to the

are

cartilage

cells characteristic showing iianv passage of blood

dissection

that

the

direction

of the

careful

rotational to

vertel)ral

cartilage infant

newborn

layers

the

\Vithstalld

of

of the a

By

maiy

FI(;.

section

of

bone. \Vhen above

1931). protrudes. turgor.

The It

is

:30(5

R.

doubtful,

of

if this

however,

disc

is divided the

turgor

horizontally

nucleus

seen

the

on

vertical

I.

HARRIS

AND

is an inherent

property

nucleus

not

does

section

may

the

remaining

frozen

adjacent

vertebral

l)etweefl

them.

took

of

of

The

body

and

increase

the

in

part

compress

of

range

of

changes

that

coiled

spring,

are

pulling

nucleus

of

the

its

components,

seen

The

substance

by

herniation

equivalent

to

experimental

of by

they

consequent the

nucleus

the

spine can

no

into

through longer

give a trivial

resist

plate

by

of

cartilage. plate,

the

alignment

A spine

does no

not

Two

was

the

possible

nucleus

fixed

pulposus

vertebrae

elasticity

was

protrude.

movement of

rigidly

of

(Fig.

the

fibres

These

observations

disc of will

4).

of

to

posterior abnormal Similarly

the

unit

adversely

the

deformation

joints

may and

movements when of THE

on

posterior add

be

the

to

integrity

of

of the

cartilage

plate Desiccation

fibres

the

nucleus

by

the BONE

damage lose body AND

all

nuclear

ligaments.

annulus

a

resistance

movements

the

is

the

likened

resilient

the

to

OF

increased

in excessive

the

JOURNAL

direction,

an

Loss

in

result

and

one understand

can

others.

In it

displacement.

to

the

depends the

annulus.

in

annulus

nucleus. diameter

extension

such

easier

a defect

and

the in

permits

against on

through

nucleus

it

The

coupling

of

annulus

make plates

body

by and

the

vertical

movement

the

cartilage

react

of the

injury.

efficiently

the

vertebral

annulus,

rise

excessive

degeneration.

and

its

prevented degree

in

of

reduce

posteriorly

excessive

allows

stability the

an

displacement to

is

displaced

incision

of which

the

tends

deformation

annulus

bodies

to the

also

protrusion

experimentally.

the

resist

a small with

extirpation

damage can

of

vertebral to one

hyaline cartilage

that

to

and

is

limits

directions.

damage

the

contraction

the hyaline

nucleus

the

is to

pulposus This

through

pulposus.

an intervertebral that

unopposed

Protrusion

due

annulus

pulposus

in association the

tested

a manner

between

disc

to the

the

thaw.

is largely

the

segments

all

in

the

cartilage

been

the

annulus

nucleus

movement

to

annulus with

state

to

nucleus

nucleus The

the

has in such

diameter.

the

\Vhen

suggests

it. of the

horizontal

of

at

due

the cells.

allowed

pulposus

functions

division

removal

with

except

into

frozen

transfixed

nucleus

spine

Experimental

hypothesis

then

be

of the blended

be followed of the cartilage

the

nucleus. This

3

junction intimately

In

were

anteriorly.

and

This

compresses

its

displaced

can

level

main

the

fibres

was

the

weight of

flexion

are

spine

which

fibrosus

One

fibres

fibres. bodies

‘ ‘

the

longitudinally.

every

turgor

annulus

of the

The

at

place ‘ ‘

of

annulus

annulus divided

and

The

appearance

of the

protrude.

FIG.

The histological Notice how the and the direction

I. MACNAB

is

sustained

their

elasticity

weight JOINT

or SURGERY

by

(‘HANGES

STRUCTURAL

movement. in

If there

volume

of the

height.

This

is a uniform nucleus

will

loss

the

occur

IN

THE

LUMBAR

of elasticity

annulus

throughout

protrudes

whenever

the

the

around

patient

its

assumes

that

of fibrous the

a local

tissue

nucleus

loss

of elasticity,

replacement

.

The

I 945,

(Figs.

5 and

Piischel

1 930,

Beadle

inspissation into

of

destruction

of

the

disc

found

when so. called

associated in

the

disc

position.

It

loses

is

quite

through vertebrae. not bulge

hyalinisation

give

rise

or

to

a localised

a localised

area

herniation

of

the

of

6).

The

disc

can

the

degenerative

process

is a complex

be

summarised

with

increasing

with

this

metaplasia

be

properly in

of with

regarded

the

body.

found

in

of thirt’.

degeneration

increasing

there the

end

of the

are

annulus

second

become (Coventry

saving

that

it consists

conversion

of

brown

degeneration

into

decade.

nature

phe1omenon by

microscopic

To

denote

changes

the

the

sixth

normal

the

ground and

fibrocartilage,

herniation

of

is nothing distinguish

avoid

and

the

nuclear

ageing,

could

upon

be about

them the either

which

coml)arabie

intervertebral

specific

confusion showing

ageing

an decade

that

those of

as

However,

There “

age. to

structural

at or

it may

plate

DISCS

retrogressive

associated

cartilage

commonly

paper

development a

ageing

) but

I 931

INTERVERTEBRAL

spongiosa.

elsewhere

this

greatest

components,

in a man

with

retained

of

could

THE

Associated

hyaline

disc



its

the

vertebral

seen changes

degree

the

variations

changes

structural of

all

IN

changes

elements.

the

into

Such age

of

formed

hyalinisation substance

reaches

structural

evident

a gradual

substance

disc

onwards

increasingly of

upright

pins passing between these levels but does vertebrae.

area

ilijury

CHANGES

intervertebral

then

ci al.

from

or a decrease

and

pulposus. DEGENERATIVE

From

a localised

resulting

fibres

4

FIG.

Two vertebral bodies have been fixed by Roger-Anderson them in such a manner that no movement is possible Notice how the nucleus pulposus bulges at all other in the disc between the rigidly fixed

conceival)le

annulus

circumference an

307

I)ISCS

INTERVERTEBRAL

from

term

disc described the

be

changes

structural or

to

changes “

an

superimposed

the

a degenerate

degeneration

prematurely may

as pathological

the

“disc

with

presenting

will

be

exaggerated the

effects

of

injury. When normal voL.

the

structural

stresses 36

B,

xo.

aIld 2,

MAY

changes

strains 194

inflicted

of

age on

occur the

prematurely

unstable

segment

during

an

max’

damage

active the

period

of

disc

severely.

life,

N.

The

annulus

tears

show

may

may

occur

tears

(Figs.

HARRIS

running

anywhere

postero-laterally

I.

on 7 and

MACNAB

I.

concentrically

the

8).

ANI)

periphery,

or more but

Sometimes

they

commonly

they

are

are

section

of twenty. the annulus

The

radial

extrusion

or

of nuclear

5

intervertebral disc taken from a man pulposus is er gelatinous and the fibres of ill defined. l’he nucleus blends into the fibres

of

a lumbar

nucleus

fibrosus

an

The posteriorly

.-

FIG.

horizontal

radially. common

with

associated

‘cv’-.

.\

most

are

of

the

annulus.

A

.

FIG. Horizontal

section

thirty-five.

This

which

is

annulus

of

disc

relatively become

a

lumbar

shows

intervertebral

the

smaller

in

increasingly

prominent.

invariably

material.

Although

The

extravasated

into

the

spongiosa

The

posterior

these blood of the and

tears is derived vertebral postero-lateral

occur

ill

from

disc

characteristic size. It also

These

found

with

an

avascular

taken

from

inspissation shows how are

the

the

increasing

changes

a man of the nucleus, fibres of the that

are

age.

area

a concomitant

of

they

injury

are to

frequently

the

haemorrhagic.

cartilage

plate,

opening

body. tears

are

of

clinical THE

significance. JOURNAL

In OF

BONE

the

region

AND

JOINT

of such SURGERY

STRUCTURAL tears age

displacement group

of the

in which

character

and

CHANGES nucleus

these

tears

spontaneous

IN

THE

is resisted are

most

extrusion

LUMBAR solely

section

of a lumbar

by

frequently

the

However,

intervertebral

weak

found,

is unlikely.

FIG.

Horizontal

INTERVERTEBRAL

7 disc

showing

DISCS

posterior

the

nucleus

even

when

a posterior

ligament. has

the

tear

309

lost

In

its

nucleus

of the

the

gelatinous has

become

annulus.

p

8

FIG.

Horizontal

section

annulus.

Note

of the

a lumbar small

size

intervertebral of

the

disc nucleus

developed

inspissated and

and

extension

to extrusion

@f such

Deposits VOL.

36 B,

contains of the

NO.

many spine. a nucleus

of

calcium

2,

MAY

are 1954

formed

the

an dark

antero-lateral

tear

discoloration

of the

that

has

in it.

elements

in its

It is conceivable

that

unprotected

posteriorly.

occasionally

showing and

found

substance

a sudden in

prematurely

it is still unguarded aged

displaced

on

flexion

could

discs.

Such

flexion give deposits

rise

310 are

R.

seen

grallular The from

in 9).

the

nucleus

blood

grown disc

both (Fig.

of

a

pigments

through ma

annulus

and

in

in

degenerate deposited

defects

result

I. HARRIS

in

the

plate

(Figs. the

FIG.

9

repeated and tissue

the

injury

fragmentation

nucleus

is barely

surrounding

THE

The

EFFECTS

vertebral

is lipping

several

or

bodies-A osteophyte

of the

cavities

OF

DISC

the

at

the

(Fig.

represented

bottom

observed of

either

brownish

8).

nucleus

lumbar into the

occur

DEGENERATION

commonly formation

may being

be

or

discoloration from

Severe

(Fig.

amorphous

injury

10).

derived

vessels to

With

that a

have

degenerate

constant

and

disc pulposus.

10

second haemorrhage

disc

a

first lumbar intervertebral calcium in the nucleus

the

recognisable,

may

haemorrhages 7 and

into

FIG.

of

they

shows

of minute

haemorrhage

section a massive

MACNAB

and

commonly

section of the a deposit of amorphous

Horizontal showing

I.

nucleus

a result

cartilage

massive

Horizontal showing

the

disc as

AND

vertebral

intervertebral nucleus pulposus.

11).

The

by

of which

ON

radiological bodies. THE

can

a

disc

annulus

fibres

loose

shreds

few

be seen

the

pitted

SURROUNDING

shredded

of brownish cartilage

plate.

STRUCTURES

manifestation Although JOURNAL

are

of disc our

OF

BONE

degeneration

investigations AND

JOINT

lead SURGERY

STRUCTURAL us

to

suppose

clinical

that

significance

investigation

being

lies

chiefly

the

type

in

involved

LUMBAR

lipping

is related

lipping

is not

at present.

that

they

that

The

posterior

that

is

to

joints.

not has

are

damage

to the

say,

senile

changes

will

when

damage

severe

with

mechanics

probable the

occasioned

and

occur

by

degenerative

In

roll

Once

and

flexion

1)odies

of an

of osteophvtes

degeneration

effect

on

the

subject

importance

of disc

the

but

Stabilit\’

many

in the

disc

also of

becomes in the

behind

the

found

arc

the

vertebral

of the

axis on

is so

flexion

cranial

through

posterior

are 14 and

36B,

body.

NO.

joints

associated

with

15).

It is partly

2,

1954

taking

rocking the

joint

ball-bearing; and

place

The give

the

stead’

rise

vertebral

the

I)etween

movement.

adjacent

remains of the

an

disc

constant

of the

the

spinal

that

in

position; joints,

trauma

occasioned

of disc

variability shift

degeneration

posterior

the

of

to a rocking

the

axis

when by

rise these

degeneration position

OccasioI1all\

rise

giving

change

h’pothesis

of the

is occurring.

it gives

every

immediately The

with

antero-posterior

with

disc

nucleus.

presence The

of movement commonly

with

In

alters the

is Compatil)le

unpredictable.

permits

extension through

in front and

pulposus.

and

and

passes

immediately

more

repeated

axis

movement

it

but

a guide

of flexion

the

type

Sometimes and

axis

nucleus

that 13)

as

movement the

irregular

12 and

a spinal

irregular.

irregular

pronounced

acts joints

extension

the

of

joints.

disc showing marked are fragmented and there of the nucleus pulposus.

pulposus

the

over

person,

zvgapophysial

component

theposterior

it passes

is most of the

(Figs.

vertebral the

extension

rock

axis

is indicative

irregularity

1)odies

flexion

full

throughout

bodies

behaviour the

; in full

is progressive

fibres

that

In

posterior

11

substance

and

the

of a young

component.

lumbo-sacral

and

experiment

the

and

disc

.

the

excessive

by

disc

the

general1’

coincidental;

--

nucleus

occurred,

to

-

annulus

gel

of movement.

nucleus

position the

has uneven,

been

change

the

the

in

are

is partly

in

found

one

other

the

in the

incompressible

degeneration

It has

of

clefts

1)0th

of

discs

relationship

damage

derangement

The

extension

overthis

segments

VOL.

instances,

is the

intervertebral

are

severe

section

the This

changes

changes

are

(Figs.

in most

the

its

concomitantly

correspondingly

disintegration.

the

and

in

FIG.

the

that

:31 1

I)ISCS

problem

presence

joints.

structural

Horizontal

of

This

place

posterior

r-

that

degeneration

changes

severe

associated

altered

the

disc clear.

only

taken

joints-Degenerative

with However,

they

of

to all

It seems

denote

degeneration

at

INTERVERTEBRAL

segment.

associated

to

THE

of vertebral fact

disc

IN

osteophytic conducted

the

of

CHANGES

the

vertel)ral

or tilting

of movement it does

so, flexion

to very

severe

irregular

of

passes and

damage

movements

312

N.

that

initiates

The

instal)ilitV

fractures

the

degenerative with

articular

HARRIS

changes

associated

of the

I.

facets.

AN1)

which

some

of

The

I.

are

these

MACNAB

seen

in the

structural

frequency

with

posterior

changes which

joints in

such

the

(Macnab

disc

fractures

1950).

predisposes

are

found

to

suggests

p.

FIG. Figure

in

extension.

Figure

lip

articular

may

are facet

Disc

L.3

13-On

on

L.4.

The

fiexion

of

well

be

not

uncommon,

can

degeneration

be

radiograph the

spine

has

the

been

body

taken

of L.3

can

the

patient

forward

on

FIG.

sustained found

with

moves

14

of the spine taken in full extension facet rocks open when the spine

they

dorsal

13

FIG.

of

FIG.

l

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