C H A P T E R

20

Degenerative Lesions

of the Spine:

Herniated
Intervertebral Disks

and Spondylosis

Marshall B. Alien, Jr.
J. Allan Goodrich

Hemiations of intervertebral disks result from trauma or
physical stress of varying degrees. Major trauma is usually
the cause in children and young adults. Hemiations in re-
sponse to trauma may occur throughout life, but most disk
hemiations are associated with varying degrees of degenera-
tion of the intervertebral disk and of the surrounding bony
elements.

Frequently, the trauma that initiates symptoms seems al-

most incidental. Thus, it is appropriate to discuss disk'her-
niations as a part of the overall degenerative processes of the
vertebral column. Approaches to diagnosis and treatment are
usually parallel, if not the same.

PATHOGENESIS OF DEGENERATIVE

CHANGES IN THE SPINE

Vertical strength of the spine is maintained by the column of

vertebral bodies with its interspersed disks. Located on
either side of the spinal canal are two columns of facets

which contribute to maintenance of the vertebral alignment
as well as vertical strength. The relationship of facets to
vertebral bodies is assured by the bony pedicles and laminae,
which also protect the neural elements. However, these fixed

bony parts and the intervertebral disks contribute to neuro-
logical deficits as degenerative processes of the skeleton and
the intervertebral disks develop.

Intervertebral disks are made up of a central core, the

nucleus pulposus, surrounded by bands of fibrous tissue, the

annulus fibrosis. (See Fig. 20-1.) Separating the soft parts of
the disks from the vertebral bodies above and below are
cartilaginous plates. Extending longitudinally along the ver-
tebral column are the anterior and posterior longitudinal
ligaments which blend with and strengthen the annulus
fibrosis.

In infancy, and early childhood, the nucleus pulposus is

gelatinous, containing hydrophilic polysaccharides, which
are responsible for a water content in excess of 80 percent.''

2

The annulus fibrosis is composed of concentric layers of
collagenous fibers that are attached to the adjacent verte-
brae.

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The fibers are directed obliquely between the verte-

brae in successive layers that are perpendicular to each other.
Elasticity of the intervertebral disks is provided in large
measure by the annulus fibrosis.

With aging, the intervertebral disk deteriorates. The struc-

ture of its polysaccharides undergoes change, and the disk
loses much of its hydrophilic property. This results in loss of

some of its water content. Fibers of the internal layers of the

annulus fibrosis grow progressively into the nucleus pulpo-
sus. The disk becomes amorphous, sometimes discolored,
and increasingly fibrotic.

2

(See Fig. 20-2.) It develops more

tears,

5

loses height, and frequently breaks through cartilagi-

nous plates into the vertebral body, protruding or expelling
fragments out of the intervertebral spaces into surrounding
areas. This results in pressure on adjacent structures and

contributes to the development of hypertrophy of adjacent
bone edges, producing osteophytes, a process that, in the i
extreme, results in "traction spurs."

5

As the spinal cord passes through the spinal canal, it gives

389

OA.)

Figure 20-1 Diagrammatic illustration of lumbar intervertebral
disk, showing central nucleus pulposus surrounded by annulus
fibrosis and anterior and posterior longitudinal ligaments (A).
Photograph of an autopsied spine showing multiple disks and their

relationships to the empty spinal canal, above, and the spinal cord,

below (B).

off nerve roots which exit through the neural foramina—
spaces delineated rostrally and caudally by pedicles, ven-
trally by the adjacent surfaces of the vertebral bodies and the
interspaced intervertebral disks, and dorsally by the facets.

Degenerative changes of intervertehral disks and the adja-

cent vertebral bodies, or of the bony facets, compromise the
spinal canal and the neural foramina. Disks protrude or
herniate. Osteophytes develop at the edges of the vertebrae,
or facets and bony malalignments occur. (See Fig. 20-3.)

Figure 20-2 Diagrammatic illustration of degenerated disk
showing the nucleus pulposus in the center surrounded by a
degenerating annulus fibrosis.

Disk hemiations and hypertrophy of bony elements appear
along the anterior and lateral surfaces of the spinal column.
ventral to the neural foramina. These produce dysphagia
when they present in the neck

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and back pain in lower

segments, along with a number of symptoms that are less
discrete than those related to compromise of the neural
elements in the spinal canal.

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Such changes are collectively

referred to as spondylosis.

Disk hemiations into the spinal canal may present medi-

ally, compressing the spinal cord or cauda equina, or later-
ally, under nerve roots approaching or in the neural fora-
mina. Lateral hemiations are notorious for producing pain
with loss of motor function in the distribution of the affected
nerve roots. Pain along the distribution of a compressed

nerve root may be in part a result of edema.

10

Spondylosis—most prominent at the epiphyseal plates of

the vertebral bodies and the facets—represents degenerative
changes that usually become apparent radiologically in
young adults" and prominent in later life.

Exostoses of vertebral bodies adjacent to intervertebral

disks are evident in areas of trauma or stress and thus more
likely to occur in the cervical and lumbar areas than in the
thoracic segments. Osteophytes may be related in part to the
elevation of periosteum, with consequent stretching or dis-
placement of the collagenous attachments to the vertebrae.
Facets are likewise subject to hypertrophy of bony edges as
well as degeneration of cartilaginous elements. Ligaments,
which provide structural stability in young individuals, be-
come lax as degeneration continues, partly a result of
stretching or tearing and also a result of reduction in the
height of intervertebral disks and degeneration of the carti-
laginous plates in the facets.

Hypertrophy of the posterior edges of the vertebral bodies

results in compromise of the anterior-posterior diameter of
the spinal canal. This may add to any compromise produced
by posterior protrusions of intervertebral disks. The anterior-
posterior diameter of the canal is usually most severely
compromised radiologically between the posterior-inferior
edge of a vertebral body and the anterior-superior edge of a
subjacent lamina. Narrowing of the canal may be further

DEGENERATIVE LESIONS OF THE SPINE: HERNIATED INTER VERTEBRAL DISKS AND SPONDYLOSIS 391

Figure 20-3 Diagrammatic illustration of sagittal view of spine
showing disk protrusion anterior anteriorly and posteriorly with
spondylosis posteriorly (A). Photograph of a sagittal segment of
the vertebral column shown by magnetic resonance imaging (MRI)
with degenerative disks and an extrusion at the L5-S1 interspace,
arrow (B).

potentiated by infolding of the ligamentum flavum (often
reported as "hypertrophy"), in large measure a result of
reduction of the interlaminar spaces resulting from the de-
generative changes described above.

Compromise of the lateral compartments of the spinal

canal results from hypertrophy of the posteriolateral edges of
the vertebral bodies and the facets.

12

Narrowing of the lateral

compartments of the spinal canal usually produces symp-
toms related to nerve roots. Such symptoms are accentuated
by soft disk protrusions whenever they are present. Conse-
quently, these symptoms may be relieved by removal of

small fragments of disk material, even though large osteo-

phytes may be the primary offending elements.

Compromise of the neural foramina by spondylosis is

often produced by derangements of the facets.

5

Hypertrophy

occurs in both the superior and inferior processes. In the
lumbar area, hypertrophy of the superior process is likely to
impinge on an exiting nerve root, while hypertrophy of the
inferior facet is more likely to compress the posterior com-
partment of the spinal canal and, consequently, the central
portion of the canal.

12

Malalignment of facets adds to the compromise of the lateral

compartments of the spinal canal, especially in the lumbar
area. When a superior facet process of a lower vertebra moves
cephalad to an inferior facet process of the superior vertebra, it
can directly impinge on an exiting nerve root.'

2

Such derange-

ment is accentuated by standing or walking and reduced by
sitting or lying down. Interestingly, there are usually very few
associated neurological deficits or stretch signs—making the
clinical diagnosis of this derangement difficult.

When degeneration of facets becomes severe and ligaments

lax, vertebrolisthesis may result. In the lumbar area, spondylo-

listhesis, as a result of degenerative processes, is most likely to

occur at the L4-L5 level, but it is also seen at the L5-S1 level.
Retrolisthesis may appear at an adjacent level, but it is most
likely to be found in the upper cervical levels, C3-C4 and
C4-C5.

13

Such severe derangements compromise the spinal

cord and nerve roots in the cervical area and nerve roots and
distal cauda equina in the lumbar area.

Even more extensive derangements may be associated

with scoliosis. (See Fig. 20-4.) In addition, the spinal canal
may be compromised by ossification of the posterior longi-
tudinal ligament, producing radiculopathies and/or myelo-
pathy.

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17

This lesion has been reported more frequently

in Asians, but it is also seen in Caucasians. It is most
commonly encountered in the neck but is reported at the
thoracic and lumbar levels as well.

18

Intervertebral disks can bulge or extrude fragments at any

age, but hemiations are most prevalent in the young to
middle-aged adult. Osteoarthritic lipping, although com-
monly seen in radiographs of young adults, becomes more
apparent in later years and is likely to be the primary basis
of symptoms beyond the age of 40.

Acute hemiations of intervertebral disks can occur at any

level in the vertebral column but are more common in the
lower lumbar and lower cervical levels. About 90 percent of
hemiations in the lumbar area occur at the L4-L5 and L5-S 1
levels, with most of the remainder occurring at the L3-L4
level. Thoracic disks also hemiate, but they do so less
commonly than in the lumbar and cervical areas. Spondylo-
sis occurs throughout the spinal canal; however, vertebral
osteophytes are most prominent at the levels mentioned.

Constrictions of the spinal cord and cauda equina may occur

throughout the spinal canal, but they are most often encoun-
tered at C3-C4 and C4-C5, and L4-L5, respectively.

13

Cases of diffuse constriction of the thoracic spinal cord are
also being reported.

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392 CHAPTER 20

(A) (B)

Figure 20-4 Photograph of x-ray of lumbar spine showing degenerative scoliosis of the lumbar spine.

A. Frontal view. B. Lateral view.

CLINICAL SIGNS AND SYMPTOMS

SIGNS ANT) SYMPTOMS OF HERNIATED
INTERVERTEBRAL DISKS AND SPONDYLOSIS OF
ADJACENT BONY ELEMENTS

Acutely hemiated intervertebral disks in the lateral compart-
ment of the spinal canal typically present with pain in the
area of the hemiation. with radiation in the distribution of
the affected nerve root. (See Fig. 20-5.) Thus, pain from a
hemiated cervical disk radiates into the adjacent upper ex-
tremity, and pain from ruptured disks in the lumbar spinal
canal radiates into the ipsilateral lower extremity. Onset of
symptoms frequently follows trauma, which may vary in
severity. A minor abnormal step or sudden rotation of the
head will often set off acute symptoms. Alternatively, symp-
toms may begin spontaneously, especially from lesions in
the cervical area. Another paradox is that pain in the site of
the hemiation may be insignificant or even absent in the face
of acute radiating pain.

Often there is localized pain for weeks or months prior to

the radiating pain, and the pain may radiate into the extrem-
ity episodically, extending further down the extremity with
each episode. There may be pain in the paraspinal area for a

few days or months, followed by pain radiating to the hip for
another period, then it begins to radiate to the back of the
knee and eventually to the ankle or foot. Symptoms are often
intermittent, with pain being present either locally or in the
distribution of the nerve root for a few days to weeks,
following which there is often relief for weeks to months.
The Valsalva maneuver usually exacerbates pain during
acute episodes. Pain is relieved—or at least lessened—by
bed rest. Persistent pain may demand aggressive therapy.

Signs of a laterally hemiated intervertebral disk include

hypalgesia in the cutaneous distribution of the nerve root,
with weakness of the muscles innervated by that root. Atro-
phy of the innervated muscles occurs when the root com-
pression persists. Specific signs related to hemiations at
common sites are described in subsequent paragraphs.

Major hemiations in the lateral spinal canal or hemiations

into the medial portion of the spinal canal are likely to result
from significant trauma. In the cervical area, the hemiation
may be the result of a vertebral dislocation. Major extrusions
into the spinal canal produce paralysis below the level of the
lesion. The spinal cord is compromised in the cervical area,
and the cauda equina is affected in the lumbar area.

The anterior portion of the spinal cord can be severely

compromised by extrusions in the cervical area. Such lesions
cause paresis, with loss of pain and temperature sensations

DEGENERATIVE LESIONS OF THE SPINE: HERNIATED INTERVERTEBRAL DISKS AND SPONDYLOSIS 393

(A) (B»

Figure 20-5 Diagrammatic illustrations of hemiated intCTvenebral <BA at lombar level. Note
relation of normal disk (A) compared to medial protrusion fragment (B).

below the level of the lesion. Sensations of vibration and
position are frequently retained. Compression of the cauda
equina will produce paresis below the level of the lesion and

loss of control of sphincters. Inability to urinate or defecate
may accompany smaller lateral hemiations because of the
resulting pain.

A few reports have called attention to hemiations of

intervertebral disks from the anterior or lateral surfaces of
the vertebral column. In the lumbar area, hemiations produce
symptoms by distortion of the fibers in the periphery of the

iimulus fibrosis and, perhaps, the sympathetic fibers.

9

Com-

plaints of pain in the back, with radiation into the inguinal
areas or the thighs, are common.

8

.

9

Spondylotic spurs are

frequent.

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In the cervical area, dysphagia may result from

either acute hemiation or spurs.

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Symptoms resulting from Spondylotic lesions in the spinal

canal often begin acutely, following injuries of varying
severity, as do symptoms following acute hemiations. How-
ever, symptoms of Spondylotic lesions are usually" more
•subtle in onset than those related to acute hemiations. Like-
wise, symptoms may be intermittent for months or years.
Signs of osteophytes located in lateral compartments of the
spinal canal are frequently similar to those of acute lesions.
However, signs of nerve root involvement in the lateral
recesses may also be negligible for prolonged periods.

12

Spondylotic lesions compromising the spinal cord of the

cervical and thoracic levels are often associated with mini-
mal or no pain, resulting in the subtle onset of paresis and
upper motor neuron signs below the level of the lesion.

23

In asymmetric lesions there may be Brown-Sequard signs

below the level of the lesion, with hyperactive reflexes on
the ipsilateral side and loss of sensations of pain and tem-
perature on the contralateral side below the lesion.

24

In other

cases, the sensations of vibration and position may be im-
paired.

25

Hyperextension injuries in the presence of Spondy-

lotic lesions of the neck cause the "central cord syndrome,"
with disproportionate weakness and impairment of sensation
in the upper extremities when compared to the lower ex-
tremities.

26

Frequently, there is quadriparesis, which may

involve all extremities, but the lower extremities recover
more rapidly than do the upper extremities.

Severe stenosis of the lumbar spinal canal usually causes

paresthesias and claudication, which may be difficult to
differentiate from claudication in the lower extremities due
to ischemia. Paresis eventually results if the cauda equina is
not decompressed.

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The history is most important in

differentiating vascular from neurogenic claudication. Vascu-
lar claudication is usually relieved almost immediately after
cessation of walking. Neurogenic claudication, on the other
hand, commonly requires 15 to 30 min of rest prior to
improvement in symptoms. Also, patients with neurogenic
claudication commonly find that a flexed posture relieves
their symptoms. This is thought to be due to anatomically
opening the neural foramina to their maximum capacity.

While spinal stenosis is divided into central and lateral

types, the two coexist more often than not. Physical findings
such as specific motor weakness and especially "stretch
signs" by straight leg raising are often absent. The diagnosis
should be suspected in the older patient with a history of
pain and numbness in either or both legs which is exacer-
bated by activity and improved after a prolonged period of
rest. The diagnosis is confirmed by appropriate x-rays, CT,
or MRI scans, as well as by myelography.

SYMPTOM AND SIGN COMPLEX ASSOCIATED
WITH THE MORE COMMONLY OCCURRING
HERNIATED CERVICAL DISKS

The most commonly hemiated disks in the neck are at the
C5-C6 and C6-C7 levels. Laterally hemiated disks at the
C5-C6 level usually compress the C6 nerve root and pro-
duce paresthesias and numbness in its distribution. In the
distal portion of the extremity, this includes the thumb and
index finger. There is frequently demonstrable weakness of
the biceps muscle, and the biceps and radial periosteal
reflexes may be diminished or absent.

Hemiation of an intervertebral disk at the C6-C7 level

usually irritates the C7 nerve root and may produce hypalge-

sia and paresthesias in the middle finger. Objective evidence

of involvement of the index finger, as well as the thenar side
of the ring finger, is variable. The triceps muscle receives a

394 CHAPTEK ;

large portion of its innervation through the C7 nerve root. Tt
is often weak, a finding which is usually demonstrable if the
reflex is depressed or absent.

A herniated disk at the C7-T1 level compresses the C8

nerve root and may be responsible for hypalgesia in the
hypothenar portion of the ring and the fifth digits. Sensory
changes extend up the forearm to about the junction of the
middle and distal thirds. Hypalgesia in this distribution is
helpful in distinguishing deficits resulting from compression
of the C8 nerve root from those resulting from compression
of the ulnar nerve at the elbow.

Signs may be absent or nonlocalizing.

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One example

relates to sensory changes in the C8 distribution, sometimes

seen in association with herniated disks at higher levels.

They may be the result of pressure on elements of the
brachial plexus by muscles or bony structures in the area and
could account for some cases of the "thoracic outlet syn-
drome." Some cases clearly resolve with treatment of her-
niated disks at higher levels. Muscle spasm is thought to be
the cause. Apical lung tumors (Pancoast tumors) may also
present with paresthesia in this distribution and should be
considered, especially in patients with a long history of
smoking. Chest x-rays with apical-lordotic views are helpful

_in the diagnosis of Pancoast tumor

SIGNS AND SYMPTOMS OF COMMONLY
HERNIATED LUMBAR INTER VERTEBRAL DISKS

The most commonly herniated disks in the lumbar area are
at the L4—L5 and L5-S1 levels, with a smaller number of

hemiations at higher levels, usually at L3-L4.

A laterally herniated disk at the L3-L4 level usually

impinges on the L4 nerve root, producing some weakness of
extension of the knee and hypalgesia of the skin over the
anterior surface of the knee which extends into the anterior
and medial surfaces of the leg, frequently about halfway
down the leg.

The knee jerk is usually diminished or absent. Since

extension of the knee relaxes the nerve fibers to the extensor
muscles of the thigh and sensory fibers crossing over the
knee, straight leg raising may not produce pain. However, if
the patient is placed in the lateral decubitus position with the
affected side up, the hip hyperextended and the knee flexed,
or if the patient is placed in the prone position and the knee
flexed, pain may be severe, reproducing the patient's symp-
toms ("the reverse straight leg raising test" or "femoral
stretch test"). Femoral neuropathy due to diabetes and retro-
peritoneal masses leading to compression of the L4 nerve
root are to be considered in the differential diagnosis.

A disk hemiation at the L4-5 level impinges upon the L5

nerve root, which usually produces decreased sensation to
pinprick over the great toe and the medial one half to
two-thirds of the dorsum of the foot. The pattern of hypalge-
sia over the anterior surface of the leg may vary. There is
usually weakness of dorsiflexion of the great toe, and there
may be atrophy of the intrinsic muscles of the foot. Walking

(A)

(B)

Figure 20-6 Examination of patient for pain on straight leg

raising in sitting position (A) and while lying supine (B).

on the heels may be impaired. Raising the leg, extended at
the knee, usually reproduces the pain. (See Fig. 20-6A and
B.) The pain can be exaggerated by dorsiflexion of the foot.
There may be tenderness to palpation over the ipsilateral
paraspinal muscles in the area of the L4-L5 interspace.

A herniated disk at the L5-S1 level usually compresses

the first sacral nerve root and produces hypalgesia over the

396 CHAPTER ;

Figure 20-7 Plain radiograph and myelogram of cervical spine;
lateral views showing positive osteophytes at the C5-C6
interspace.—. ;,»<•

nodes, calcification of intervertebral disks, and gas within
intervertebral disks are indications of degenerative change.
(See Fig. 20-8A lo C.)

CT demonstrates fractures, stenosis of the spinal canal,

hypertrophic changes in the facets, calcification »f the poste-
rior longitudinal ligament, and evidence of disk protrusions
and/or disk extrusions. Reconstructions may be made to
demonstrate malalignments.

The application of CT scanning to investigate degenera-

tive lesions of the spine has emphasized the need for corre-
lation with clinical signs and symptoms. (See Fig. 20-9.)
One review of scans made in asymptomatic patients demon-
strated abnormalities in over a third of all patients exam-
ined.

34

Nearly 20 percent of patients below the age of 40 had

evidence of hemiated disks, and half of the patients exam-
ined above the age of 40 had various degenerative lesions,
including hemiated disks, degeneration of facets, and steno-
sis of the spinal canal.

MM has proved to be even more definitive than CT in the

demonstration of defects of the vertebral column.

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(See

Fig. 20-10.) The vertical sagittal images demonstrate long

segments of the spinal column, outlining the vertebral bodies
and the intervertebral disks. (See Fig. 20-11A and B.) Cross
sections reveal the relationships of the disks to the thecal sac
and nerve roots. Even though bony elements are not as well

delineated as on CT, evaluation of alignment is better.
Spinal stenosis and arachnoiditis are also well outlined.

37

The administration of gadolinium to patients having

previously undergone surgery helps to differentiate disk her-
niations from scarring.

38

Dynamic MRI has revealed expla-

nations for the development ofmyelopathy by demonstrating
compression of the spinal cord when the neck is extended."''
MRI, as well as CT, has emphasized the importance of
clinical correlation. A recent study demonstrated progres-
sively increasing numbers of degenerative lesions in the
spine with increasing age.

40

Myelography was developed over 70 years ago. Its clini-

cal application was first reported a couple of years later.

36

I;

remains the standard for investigating etiologies of degener-
ative lesions of the spinal column. (See Fig. 20-12.) Initial
myelograms were performed with air. Oil contrast media
remained the standard for many years, but now most exami-
nations are performed with water-soluble contrast media.
These media are less toxic and provide discrete outlines of
very small lesions. A disadvantage of water-soluble contrast
media is that they are dissipated within a few minutes.
However, CT imaging performed after the contrast material
has been injected will show enhanced images for a longer
period of time, and may reveal disk herniations isolated to
the midportion of the spinal canal that can be missed without
tomography. (See Fig. 20-13.)

Diskography, in which water-soluble contrast media is

injected into intervertebral disks suspected of degeneration.
was very popular in the 1960s, but the demonstration that
degenerated disks were common and might not be associated
with radiculopathics led to considerable skepticism regard-
ing the examination. There has been a resurgence of interest
in more recent years, probably at least in part as a result of
the realization that the disks that received excessive quanti-
ties of dye and revealed extrusion into the epidural space
were abnormal even though they were not associated with
radiculopathies. Diskography is now performed in many
centers, but a major part of the diagnostic evaluation is

based on reproduction of the patient's symptoms by injec-
tion of contrast media into the affected disk space.

41

Diskitis

is a known complication of the investigation, probably a
result of organisms from the skin introduced via the needle
used to inject contrast media.

42

TREATMENT OF HERNIATED

INTEVERTEBRAL DISKS

The treatment for intervertebral disk disease has been subject
to controversy. Opinions vary as to whether nonsurgical
(conservative) or surgical treatment should be instituted and
when. If surgical treatment is selected, there is consideration
as to which form of surgery should be applied.

Early symptoms of hemiated disks frequently begin with

localized pain in the back or neck. These are common
complaints, and the causes of such pain may be many.
Often, episodes of localized pain have been diagnosed as

"mechanical," "musculoskeletal strain," or "fascitis." Pain

DBCtNHtATlVE LESIONS Of-ME SKSE- HERMAIED INTER VERTEBRAL DISKS AND SPONDYLOSIS

( A )

(B)

(C)

Figure 20-8 Spondylitic degenerarive
changes in lumbar spine. Note lateral
osteophytes at each level but most marked at
L2-L3 and L3-L4 in the frontal view. with
narrowing of the disk space, most marked at
L2-L3 in the frontal view (A). The lateral view
shows narrowing and irregularity of the disk
spaces, large osteophytes anteriorly at L2-L5,
and some in vertebrolisthesis views (B). Gas
shadows are identified by the arrows in C.

398 CHAPTER 2

Figure 20-9 Computerized tomography of lumbosacral junction

with contrast material in the spinal canal indicating hemiated
intervertebral disk.

area. Recent innovations have questioned whether diskecto-
mies should be performed by needle aspiration, by open
laminectomy, with magnification,

43

or with the use of an

enzyme that digests the intervertebral disk.

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47

In addi-

tion, with degenerative lesions of the vertebral column.
questions arise as to (1) whether spondylitic lesions in the
cervical area should be attacked through an anterior or
posterior approach, (2) whether laminectomies in the lumbar
area for spinal stenosis should be limited to one or two
levels, and (3) whether such laminectomies should be ac-
companied by a fusion and/or the use of instrumentation to
maintain alignment. Similarly, in the cervical area, contro-
versies exist as to whether some form of prosthesis should

be inserted to improve the structural integrity of the verte-
bral column.

For the purposes of this discussion, we will present the

basically accepted techniques and mention some of the
various alternatives that have been recommended.

may result from fracture, infection, arthritic involvement, or
even vertebral abnormalities. Pain is often temporary and the

symptoms will resolve with time, with or without bed rest,
heat, massage, analgesics, sedation, or anti-inflammatory

medications.

In the past, invasive techniques for investigating com-

plaints referable to pain in the spine were performed only
after the complaints had been unremitting for prolonged
periods or neurological deficits were encountered. Imaging
is currently done using much more liberal criteria. Degener-
ative changes of intervertebral disks that may be the basis
for such complaints are often demonstrated.

Imaging reveals degenerative lesions of intervertebral

disks and vertebrae in the spine even in the absence of
symptoms, but it must be emphasized that pain in the back
and neck often resolves, given time, even when radicular
signs are present. Therefore, conservative treatment of such
lesions must remain a serious consideration, even in the
presence of a positively imaged lesion, unless symptoms

persist or neurological deterioration is progressive. It must
be emphasized that hemiation of an intervertebral disk is not
a life-threatening problem. Surgery should be considered

only for severe or persistent pain, or neurological deficits.

Once a definitive lesion of an intervertebral disk or its

adjacent bony elements has been demonstrated and a surgi-
cal procedure is indicated, controversies develop as to
whether diskectomies in the neck should be performed
through an anterior or posterior approach or whether, in
association with an anterior approach, a fusion should be

performed. Similarly, opinions vary on surgical approaches
to the lumbar area as to whether fusion should be performed
in association with diskectomies, and, if so, whether the
fusion should be performed between the posterior or lateral
elements of the spinal column or between the vertebral
bodies.

Even the mechanism by which the disk is removed is

subject to question in the lumbar area. Most diskectomies in

the lumbar area are performed through laminotomies. This

approach is used by many neurosurgeons in the cervical

CONSERVATIVE TREATMENT

A period of rest seems clearly indicated following the onset
of acute pain in the neck or back before considering surgical
therapy—unless there is indication of infection, vascular
disease, tissue destruction, or significant neurological deficit.
Opinions may differ as to the types of therapy that should be
included during this period.

Pain is clearly a component of the muscle strain that

occurs in association with strenuous exercise or blunt injury
to a muscle. After a few days of rest, the pain resolves.

Bed rest is the mainstay of conservative treatment for pain

in the neck or back, which could be temporary; pain and
minor neurological deficits often resolve with time. Edema
may play a significant role in radicular pain seen in associa-
tion with hemiated disks.

10

Reduction of edema of nerve

roots could explain the remarkable clinical results that are
often seen after the administration of steroids.

The administration of heat and massage provides some

temporary relief of pain, and there does not appear to be any
contraindication to their use in the treatment of radiculopath-
ies. The authors have discouraged the use of vertebral ma-
nipulations in such cases, fearing the possibility of disk
extrusions.

It has generally been our policy to maintain a period of

bed rest for 2 weeks. During this time, radiographs of the

structures in question can be obtained along with any ancil-
lary laboratory studies where indicated, such as sedimenta-

tion rates and evaluation for arthritis. During this time,
imaging is accomplished. Even if hemiated intervertebral
disks are demonstrated, we continue to rely on rest if pain is
resolving.

In the past, the use of head halter or pelvic traction as a

supplemental treatment for bed rest has been used, but
anatomical justification cannot be demonstrated for the use
of pelvic traction, and many patients abhor the use of head
halters required for traction on the neck. As a result, the use

DEGENERATIVE LESIONS OF THE SPINE: HERNIATED INTERVERTEBRAL DISKS AND SPONDYLOSIS 399

(A)

Figure 20-10 Magnetic resonance images of disk
hemiation in lumbar spinal canal after gadolinium
sagittal view (A), axial view (B), and fragment
removed (C).

(B)

(C)

of traction as a form of therapy for temporary back and neck
pain has been discontinued in many institutions.

The use of analgesics as a supplement to rest is often

indicated, but one must be selective in the types of analge-
sics used. Narcotics are rarely necessary when patients re-
main at rest and should be avoided when treating chronic
pain of benign etiology. Peripherally acting analgesics and
nonsteroidal anti-inflammatory drugs are usually adequate.
A temporary course of steroids may be helpful.

Sedatives have been administered in many cases when the

pain is acute, especially if the patient is anxious. The admin-
istration of such drugs should be kept to a minimum.

Use of local anesthetics injected adjacent to nerve roots or

into trigger points and in the epidural space has been advo-
cated for many years. Infections in the epidural space can
occur in conjunction with the administration of epidural
anesthetics. The use of steroids has also been advocated, but
while occasional administration of steroids may not be
harmful, osteoporosis is exacerbated by their use. Cuckler
concluded from his well-controlled, double-blind study that
epidural steroid injections are of no value in the treatment of
lumbar radicular pain.

48

White reported that variable results

from epidural steroid injections were due to the finding that
as many as 25 percent of injections were misplaced.

49

He

400 CHAPTER an

( A )

(B

)

Figure 20-11 Sagittal MRI of cervical spine showing hemiated

cervical disk at the C5-C6 tewsl in (be sagittal (A) and axial (B)
planes.

recommended injection under fluoroscopic control, using a

small amount of contrast media to document location.

When definitive neurological deficits are apparent and

imaging has demonstrated a protruding intervertebral disk as
a cause and ruled out the presence of extruded fragments,
some have suggested this is an indication for percutane-
ous diskectomy as the ultimate form of conservative
care.

50

'

51

'

52

-

53

The authors' experience with this practice is

limited, and we have met with limited success.

The procedure is carried out through a needle inserted

through a cannula introduced about 10 cm lateral to the mid-
line, directed toward the intervertebral space under fluorosco-
pic control. A curved cannula has been especially devised for
insertion of a needle into the L5-S1 interspace. A diskogram

may exclude disruption of the annulus and posterior long;---
dinal ligament. Once the needle has been put in place, the d: -A
material is aspirated with an ultrasonic aspirator. Many ••;---

geons report a success rate for the relief of pain in the range :'i
70 to 80 percent; however, the authors' long-term success IE i
very small group of patients has been considerably less. A lc"«
rate of success has been reported in patients older than 5
years, and most authors have reported that pain from extruc;
fragments is exacerbated by such procedures.

In summary, it appears that patients seen with acute onset

of pain in the neck or lumbar back—with or without -
radicular component radiating into an upper or lower ex
tremity—should be given a period of rest for at least ;
weeks. This may be done at home but is better administered
in a controlled environment. We do not advocate use o:
traction but do use nonnarcotic analgesics and nonsteroida-
anti-inflammatory drugs as well as, in some cases, mild
sedation. We have not used injectable steroids. Heat and
muscle massage are given to supplement bed rest, but we do
not advocate manipulative therapy. If the symptoms appear
to be resolving after 2 weeks, this conservative therapy is
continued. Physical therapy along with muscle strengthening

exercises is instituted as the pain resolves. If the pain per-

sists despite therapy or if patients demonstrate neurological
deficits, imaging is performed to determine indications for
surgical therapy.

A definitive workup is indicated: for patients evaluated

with symptoms that have persisted for several months, in
patients who have evidence of spinal stenosis, long tract
signs or lesions in the cervical or thoracic areas, or in
patients who have claudication or pain on standing or walk-
ing with relief on sitting. This includes appropriate electro-
diagnostic studies and imaging with surgical therapy as the
ultimate objective.

SURGICAL THERAPY

Many factors enter into a decision as to whether, when, and
what type of surgical therapy is indicated in a patient with a
known hemiated intervertebral disk. While a cure rate ap-
proaching 90 percent in patients with symptoms due to
hemiated disks has been reported in the past, residual pain
persists for years in at least a third of patients treated
surgically. Pain from compression of a nerve root is relieved
in a high percentage of cases, but even when it is, there may
be residual paresthesias, and relief of back pain is far from
routine. Definitive indications for surgery are: (1) persistent
pain of such a nature that the patient cannot pursue his or her
livelihood or (2) a significant neurological deficit which is
ascribed to the hemiated disk.

OPERATIVE TECHNIQUE: LUMBAR

The standard surgical procedure for an uncomplicated her-
niated nucleus pulposus in the lumbar area is accomplished
through a unilateral hemilaminotomy.

DEGENERATIVE LESIONS OF THE SPINE: HERNIATED INTERVERTEBRAL DISKS AND SPONDYLOSIS 401

(A) (B)

(C)

Figure 20-12 Myelograms showing lateral defects from
hemiated intervertebral disks at L5-S 1 in the frontal view
(A), oblique view (B), and a lateral defect in the frontal view
at the L4-L5 level (C).

CHAPTER 20

Figure 20-13 Computerized tomogram of lumbar spinal canal

containing contrast media and showing laterally hemiated nucleus
pulposus.

The appropriate interspace is approached through a mid-

line or paramedian incision. After the paraspinal muscles are

separated from the adjacent spinous processes and laminae,

the inferior margin of the lamina above the interspace is
removed by rongeuring. The ligamentum flavum and medial
margin of the adjacent facet may be removed, but the
structural integrity of the facet should be preserved.

The spinal dura and the subjacent nerve root are usually

retracted medially. In some instances, the disk hemiation
may present in the axilla between the nerve root and the
adjacent dura, in which case the nerve root must be retracted
laterally. (See Fig. 20-14.) Extruded fragments of disk mate-
rial are removed with pituitary rongeurs. In the event of
significant protrusions when the external fibers of the annu-
lus are still intact, the annulus is incised or opened in a

circular manner.

The inner portion of the disk is removed wittf rongeurs.

The intervertebral disk space is curetted and fragments

within the interspace removed, minimizing chances of extru-
sion of another fragment- The nerve root should be thor-
oughly decompressed- a search being made for additional

fragments of disk material which might lie anterior to the
nerve root and for osteophytes that might impinge on the
nerve root in the neural foramen.

_ The presence of osteophytes that are likely to compromise

Figure 20-14 Schematic illustration of intervertebral disk

impinging on the nerve root from directly anteriorly (A), medially

(B), and laterally (C). Disk excision is most often accomplished
after moving the nerve root medially.

the neural foramen from the edges of the vertebral bodies or
the facet may require a foraminotomy, that is, resection of
the anterior and medial segments of the facet. If the stenosis
compromises the spinal canal, a laminectomy must be per-
formed. Intraoperative sonography may help locate disk
fragments or osteophytes located anterior to the dura or
nerve root.

54

Variations of diskectomy from a posterior

approach have included use of the surgical microscope and
resection through a large-bore needle.

43

Instability following laminotomy or laminectomy in the

lumbar area has been a concern for years.

55

In the past—and

even continuing into the present on many services—fusions
between adjacent posterior elements have been performed.
often routinely, in association with diskectomies in the lum-
bar area.

56

'

57

This technique has been replaced by interbody

fusion on many neurosurgical services.

58

-

59

A radical diskectomy incorporating removal of the facet

joints on either side may be followed by insertion of struts

of bone between the adjacent vertebrae for an interbody
fusion. When struts of bone are implanted, one must make
certain that cartilaginous plates have been removed at the
sties where struts are being incorporated. Fusions may be
accomplished with bone removed from the iliac crest of the

patient, or bank bone may be used with a high degree of

success. Stabilization of sites of fusion is improved by the

use of compression rods. (See Fig. 20-15.)

Excision of intervertebral disks hemiated anteriorly or

laterally to the vertebral column requires radical resection
from a posterior, anterior, or lateral approach.

9

-

21

'

60

When imaging studies have indicated that free fragments

do not lie in the spinal canal, portions of the nucleus
pulposus between the vertebrae can he removed by chemo-
nucleolysis

44

-

45

-

46

'

47

or by percutaneous aspiration.

50

-

51

-

52

-'"

The authors' persona] experience with these techniques has
met with limited success. Diskitis is the most commonly
reported complication;

61

it is a well-known complication of

diskectomy by any approach.

62

OPERATIVE TECHNIQUE FOR HERNIATED
CERVICAL DISKS

Laminotomy and resection of disk fragments has been ap-
plied in the cervical as well as the lumbar area. The tech-
nique meets with the highest incidence of pain relief when
there are uncomplicated hemiations of soft disk material.
Since disk hemiations are commonly associated with osteo-
phytic formations of the adjacent vertebral bodies and of the
posteriorly placed facets, an anterior diskectomy with resec-
tion of adjacent segments of vertebrae above and below the
disk space, as well as fusion of the adjacent vertebrae, is

preferred for many lesions in the cervical area.

58

-

59

-

63

-

64

-

65

For anterior cervical diskectomy, a transverse incision is

usually made through a crease in the neck. An alternate
incision may be made along the medial edge of the stemo-
cleidomastoid muscle. After either incision, dissection sepa-
rates the body of the stemocleidomastoid muscle and the

DEGENERATIVE LEaONS OF THE SPWE: HERNIATED INTER VERTEBRAL DISKS AND SPONDYLOSIS

403

(B)

(A)

Figure 20-15 Recurrent hemiated intervertebral disk at L4-L5
treated by excision and fusion, the latter aided by Harrington

compression rods. Plain x-rays (A, B). For comparison with similar
films after surgery (C, D).

404 CHAPTER 31'

(A) (B)

Figure 20-16 Magnetic resonance image A. Sagittal view of hemiated disk, C5-C6. B. Lateral

view of x-ray neck after surgery, showing bone graft in place.

strap muscles of the neck. The stemocleidomastoid and
subjacent jugular vein, carotid artery, and vagus nerve are
retracted laterally, while the strap muscles,, trachea, and
esophagus are retracted to the contralateral side. This bares
the anterior surface of the vertebral column with its inti-
mately adherent longus coli muscles.

A lateral x-ray taken with a needle inserted into the

intervertebral disk identifies the level. After the vertebral
column has been bared of its soft tissues—including the
longus coli muscles on either side—a transverse incision is
made in the anterior longitudinal ligament and subjacent
annulus, and portions of the disk material are removed.

Varying techniques have been described for removing the

disk material and various portions of the adjacent vertebral
bodies by Cloward, by Smith and Robinson, and, more
recently, by other surgeon s.

63

'

64

-

65

Variations include: the use of a gas-powered burr for

removal of the adjacent portions of the vertebral bodies,
curettage and rongeuring of adjacent surfaces of the two
vertebral bodies, or simply curetting the disk material

without subsequent fusion. By any method, the nerve roots
are decompressed, care being taken not to injure the verte-
bral arteries or spinal cord. Through this approach, osteo-

phytes on the adjacent vertebrae may be removed. (See Fig.
20-16.)

OPERATIVE TECHNIQUES FOR RESECTION OF
HERNIATED THORACIC DISKS

For diskectomies in the thoracic area, alternative techniques
have been described. A direct approach through laminotomy
has met with complicating paresis in a high percentage of
cases. Therefore, an approach through thoracotomy has
gained popularity.

66

'

67

-

68

An alternative procedure is to re-

move a medial segment of the rib and transverse process,
exposing the appropriate intervertebral disk.

69

Using either

approach, a segment of rib is often implanted into the disk
space after the disk and cartilaginous plates have been re-
moved.

70

(See Fig. 20-17.)

SPONDYLITIC LESIONS

OF THE SPINE

Spondylosis, the degeneration of bony and ligamentous ele-
ments of the spinal column, progresses with age. As with
lesions of intervertebral disks, neurological complications
may be related to involvement in the central portion of the
spinal canal, which impairs function of the spinal cord or

cauda equina, as distinct from involvement along the lateral
portions of the canal where lesions produce radicular signs

DEGENERATIVE LESIONS OF THE SPINE: HKRNIATED INTERVERTEBRAL DISKS AND SPONDYLOSIS 405

Figure 20-17 Herniatcd thoracic disk at T6-T7 seen on sagittal MRI (A) and axial views (B).

and symptoms. In addition, severe derangement of the align-
ment of the spinal canal—which can be the result of defor-
mation (compression) by part of a vertebral body, failure of
pedicles or facets, or relaxation of ligaments—is oftetl asso-
ciated with pain locally. These are not necessarily associated
with identifiable neurological deficits. (See Fig. 20-18.)

Hypertrophic changes of the superior and inferior edges of

the vertebral bodies increase with age. Such changes arc
more prevalent in the cervical and lumbar areas than in the
thoracic area, although they occur throughout the vertebral
column. (See Fig. 20-19.) Hypertrophy is also a common
degenerative feature of the facets.

Spondylitic spurs at the lateral parts of the vertebral

bodies located within the spinal canal and hypertrophy of the
superior facet are likely to impinge on exiting nerve roots.
Hypertrophy of the more medial parts of the posterior verte-
bral bodies and hypertrophy of the inferior facet processes

—at least in the lumbar area—decrease the volume of the
spinal canal. Playing a role in ultimately determining the
size of the spinal canal is the length of the pedicles and
laminae as determined by development, as well as the pres-

. ence of metabolic changes, which may result in thickening

of all of these bony parts.

Relaxation of ligaments that may be a result of stretching

or tears or, more often, degenerative processes may allow for
malalignment and compromise in the diameter of the canal

or compromise of the neural foramina. Another feature that
may add to compromise of the spinal canal is thickening of
the posterior elements and thickening of the posterior longi-
tudinal ligaments, which may be associated with calcifica-

SPINAL STENOSIS

Stenosis of the spinal canal in the cervical and thoracic areas
results in compressing the spinal cord, causing myelopathy
that produces weakness and upper motor neuron signs. (See

Fig. 20-20.) There are often posterior column signs as well,
especially when there is retrolisthesis. Stenosis of the lumbar

spinal canal is more likely to be associated with claudication
on standing or walking, relieved by sitting with the back in a
flexed position or by lying down. There are usually numb-

ness and dysesthesias in the lower extremities. The symp-
toms of spondylotic lesions of the lateral parts of the spinal
canal have been described earlier, and their treatment, dis-
cussed earlier, is primarily that of decompressing the lateral
compartments of the spinal canal. It seems appropriate now
to discuss treatment of lesions that affect the internal diame-
ter of the canal.

(A) (C) (B)

(D) (E)

Figure 20-18 Severe spondylosis of the lumbar spine, showing
narrowing of disk spaces, osteophyte formation, and scoliosis on
the frontal views of the plain radiographs (A). The myelogram

shows narrowing of the spinal canal (stenosis) with indentations at

every level (B, C). The patient's pain was greatly reduced by
internal fixation and fusion despite minimal anatomical
improvement (D, E).

(A) (B)

(C) (D)

Figure 20-19 Cervical spondylosis with stenosis of the spinal
canal and myelopathy treated by multiple diskectomies and fusion,
and subsequent fixation with a Caspar plate. Note the osteophytic
narrowing of the spinal canal (A) illustrated more graphically by

the sagittal MRI (B). A lateral radiograph (C) shows the multiple
diskeetomies and interbody fusions, held and internally fixed by
the Caspar plates and screws (D).

(A)

(B)

(C)

(D)

Figure 20-20 Cervical spondylosis and spinal stenosis, illustrated by a lateral plain radiograph
(A) and myelogram (B). Fixation with Caspar plates and screws is illustrated (C, D).

DEGENERATIVE LESIONS OF THE SPINE: HERNIATED INTERVERTEBRAL DISKS AND SPONDYLOSIS 409

TREATMENT OF SPINAL STENOSIS

Slenotic lesions occur at one or two levels or are more

generalized, sometimes affecting an entire section of the
spinal canal. Almost all of the cervical or lumbar spinal
canal may be involved. On occasion, especially in achondro-

plastic patients or those with hypochondroplasia, the entire
spinal canal is implicated.

OPERATIVE TECHNIQUE: CERVICAL AND
THORACIC

In the cervical area, when one or two segments are involved,
the spinal canal is usually decompressed by removing the
offending hypertrophic bony lesions through diskectomy and
fusion via an anterior approach. This proceeds in the same
way it is described for performing an anterior diskectomy,
but taking care to remove the offending osteophyles by
drilling or rongeuring.

When multiple levels are involved, a laminectomy appears

more appropriate, thus avoiding the need to immobilize a
major part of the spinal canal. This is usually accomplished by
exposing the spinous processes and laminae from C2 to C7 and
drilling a trough through the lateral edge of the laminae with a
power drill and burr. Such a technique allows the removal of
spinous processes and laminae without compromising the spi-
nal canal by the introduction of instruments.

Usually there is more space around the spinal cord at the

levels of C2 and C7. When laminectomy has been extended
to these limits, it has often gone beyond the area of constric-
tion, and the normal lordotic curve tends to allow the spinal
cord to move away from any ventral osteophytes. The facets
should be preserved wherever possible in order to minimize
the chances for deformity.

71

-

72

-

73

'

74

'

75

On occasion, disk her-

niations may occur after a decompressive laminectomy, in
which case an anterior diskectomy might be required. How-
ever, such occurrences have been rare and limited to a single
level in the authors' experience.

A refinement which has recently been recommended for

use in cervical stenosis is the suspension luminotomy, in

which the laminae are divided and separated from the lateral
elements by fragments of bone held in place by sutures.

76

This technique adds significantly to the surgical procedure
but reportedly reduces the incidence of complicating defor-
mities, and the long-term neurological outcome is reportedly
improved.

77

(See Fig. 20-21.)

For power drilling in laminectomy or laminotomy, a dia-

mond burr is usually used to drill through the laminae in
order to avoid leaving bits of metal in the wound. Retained
metal produces artifacts on images performed with magnetic

resonance.

Stenosis in the thoracic canal was thought to be rare in the

past, but reports of such lesions have appeared in recent
years.

19

'

20

It may be that more sophisticated and frequent imag-

ing has resulted in better diagnosis of this entity. Treatment is
similar to the treatment for stenosis in the cervical area.

Stenosis at a single level due to osteophytes is best treated

by a diskectomy through an anterolateral approach through
the chest, while narrowing over several segments is probably
best treated by laminectomy through a posterior approach as
described for the cervical area.

Stenosis in the lumbar area is usually limited to one or

two levels—most commonly L4-L5 and, perhaps, L3-L4 or
L5-S1. Decompressive laminectomy at the appropriate
levels is the treatment of choice.

29

Fusion will reduce the

chances for spondylolisthesis but is not routinely performed.
Interbody fusions may be performed at one or two levels.

56

'

57

Lateral fusions, between the transverse processes may be
used, or fusions may be performed in conjunction with use
of screws inserted into the vertebral bodies through the
associated pedicles and plates or rods.

69

-

70

'

78

'

79

SPONDYLOLISTHESIS

Spondylolisthesis is malalignment of vertebral bodies where
an upper body slips forward on its subjacent neighbor. The

malalignment may be asymptomatic, but there may also be
compression of nerve roots or the cauda equina with resul-
tant severe pain- The pain is often localized, but it may be

radicular, involving: the nerve root exiting at the level of the

defect, the nerve root exiting at the level below the defect, or
roots still retained within the cauda equina and located
within the center of the spinal canal that are being com-
pressed by the anteriorily displaced lamina.

Spondylolisthesis is classified as dysplastic, isthmic, de-

generative, posttraumatic, or pathological.

910

Dysplastic cases

occur in children, most often at the lumbosacral junction;
there is a strong hereditary component. Isthmic spondylo-
listhesis is subdivided into (1) lytic, in which case there is a
separation of the pars from a fatigue fracture, (2) elongation
of the pars without separation, in which case there are

frequently found fine fractures within the pars, and (3) acute
fractures in the pars. Such lesions occur in young adults.
Degenerative spondylolisthesis is found in adults, almost
invariably above the age of 40, and cases are 6 times as
common among women as men. Posttraumatic spondylo-
listhesis occurs when there is severe trauma. The fractures
are found in structures other than the pars. Dislocations
occur gradually in these cases.

Our experience with spondylolisthesis has been almost

exclusively with adults of the isthmic type and in cases of
the degenerative type. Most cases of spondylolisthesis in
children are of the dysplastic variety, and the majority can
be treated conservatively. In degenerative spondylolisthesis,
pain is the indication for therapy. The pain follows a sciatic
distribution in 70 percent of cases and a pattern of neuro-
genic claudication in 30 percent of patients.

80

TREATMENT OF SPONDYLOLISTHESIS

Treatment consists of decompression and fusion using a
posterior lumbar interbody fusion or lateral spinal fusion.

CHAPTER 20

(A) (B)

Figure 20-21 Cervical spondylosis and stenosis producing
myelopathy, illustrated on the lateral MRI scan (A), treated by
suspension laminotomy. Postoperative radiographs are presented
(B, C).

(C)

DEGENERATIVE LESIONS OF THE SPINE: HERNIATED INTER VERTEBRAL DISKS AND SPONDYLOSIS 411

( A )

(B)

(C) (D)

Figure 20-22 Spondylolisthesis treated by posterior lateral inter- of the fusion at an outside hospital (A, B). The bone grafts were
body fusion and subsequent intraspinous wiring because of failure replaced and compression rods applied for greater stability (C, D).

(A) (B)

(C)

Figure 20-23 Degenerative spondylolisthesis L4-L5 known to
have been present at least 5 years in a 63-year-old male who began
experiencing severe back and radicular pain when retrolisthesis

occurred at L3-L4 level (A, B). Treated by distraction rods and
fusion with excellent relief for 2 years (C, D).

DEGENERATIVE LESIONS OF THE SPINE: HERNIATED INTERVERTEBRAL DISKS AND SPONDYLOSIS 413

(See Figs. 20-22 and 20-23.) Most of the authors' cases in
the past have been treated with posterior lumbar interbody
fusion obtaining solid fusions and often with some residual
localized back pain, which we ascribe to residual degenera-
tive processes at adjacent levels. More recent cases have
been treated with pedicle screws and rods. In his extensive
review, Wiltse, combining decompression with a posterior
lateral fusion, indicates that removal of all the posterior
elements was associated with adequate relief of pain in about
30 percent of cases, whereas good results were obtained in
about 70 percent of cases when the decompression was
limited to the midline structures.

80

There was no good expla-

nation for this paradoxical result.

A recently introduced procedure that is becoming a popu-

lar form of therapy for the treatment of spondylolisthesis of
the more limited grades, is insertion of transpedicular screws
in conjunction with segmental plates or rods.

78

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79

The screws

can be used to draw the vertebrae into alignment.

Patients may he amhulated very rapidly after spinal fusion

of the inlerbody or inlertransverse process variety or after
fixation with pedicular screws. It has been recommended that
if patients who have been fused by intertransverse process
fusion experience progressive deformity during the early post-
operative period, they should be returned to bed rest for 6 to 8
weeks. Progression of deformity is less likely following inter-
body fusions or treatment with pedicle screws.

DEGENERATIVE SCOLIOSIS

Degenerative processes throughout the lumbar spinal column
with relaxation of the ligaments may result in the develop-
ment of scoliosis. Patients frequently complain of severe"
radicular pain. (See Fig. 20-24.) Myelography reveals evi-
dence of stenosis and defects consistent with protrusions or
extrusions of intervertebral disks. There are usually degener-
ative disk lesions with protrusions at multiple levels. Neuro-
logical deficits are variable.

Diskectomy often fails to relieve pain or may result in

switching pain from one side to the other. Our most gratify-
ing experience in the treatment of this lesion or series of
lesions has been with the use of instrumentation (see Fig.
20-25), usually with distraction rods, although laminectomy

and segmental plating appears to be equally promising, if not
superior. Degenerative lesions of the spine can be expected
to be more common in the future with an aging population.
The salvage procedures described above show promise for
making life more enjoyable for patients with progressive
deterioration of the spinal column.

Figure 20-24 Lumbar spondylosis with stenosis and scoliosis seen in the
frontal radiograph and during myelography (A). Treated by distraction rods
and fusion with excellent relief of pain despite poor anatomical realignment
(B, C).

(A) (B)

Figure 20-25 Lumbar spondylosis and scoliosis seen in frontal Treated with pedicle screw fixation and
anrl latpra! views the lateral view from a mveloeram (A, B). fusion (C, D).

Figure 20-25 Continued

REFERENCES

1. Gower WE, Pedrini V: Age-related variations in proteinpoly-

saccharides from human nucleus pulposus, annulus fibrosus,
and costal cartilage. J Bone Jt Surg 51A: 1154-1162, 1969.

2. Hendry NGC: The hydration of the nucleus pulposus and its

relation to intervertebral disc derangement. J Bone Jt Surg
405:132-144,1958.

3. Markolf KL, Morris JM: The structural components of the

intervertebral disc. J Bone Jt Surg 56A:675-687, 1974.

4. Eyring EJ: The biochemistry and physiology of the interverte-

bral disk: A study of their contributions to the ability of the
disk to withstand compressive forces, din Orth Rel Res

67:16-28, 1969.

5. Kirkaldy-Willis WH, Wedge JH, Yong-Hing K, Reilly J: Pa-

thology and pathogenesis of lumbar spondylosis and stenosis.
Spine 3:319-328, 1978.

6. Bemardo KL, Grubb RL, Coxe WS, Roper CL: Anterior cervi-

cal disc hemiation: Case report. J Neurosurg 69:134—136,

1988.

7. Brandenburg G, Leibrock LG: Dysphagia and dysphonia sec-

ondary to anterior cervical osteophytes. Neurosurg 18:90-93,

1986.

8. Cloward, RB: Anterior hemiation of a ruptured lumbar inter-

vertebral disk. Arch Surg 64:457^63, 1952.

9. Jinkins JR, Whittemore AR, Bradley WG: The anatomic basis

of vertebrogenic pain and the autonomic syndrome associated
with lumbar disk extrusion. AJR 152:1277-1289, 1989.

10. Takata K, Inoue S, Takhashi K, Ohtsuka Y: Swelling of the

cauda cquina in patients who have hemiation of a lumbar disc.
A possible pathogenesis of sciatica. J Bone Jt Surg 70A:361-
368, 1988.

DEGENERATIVE LESIONS OF THE SPINE: HERNIATED INTER VERTEBRAL DISKS AND SPONDYLOSIS 417

58. Cloward RB: Posterior lumbar interbody fusion updated- din

Orthop 193:16-19, 1985.

59. Lin PM: Posterior lumbar interbody fusion technique: Compli-

cations and pitfalls, din Orthop 193:90-102, 1985.

60. Maroon JC, Kopitnik TA, Schulhof LA, et al: Diagnosis and

microsurgical approach to far-lateral disc hemiation in the
lumbar spine. J Neurnsurg 72:378-382, 1990.

61- Blankstein A, Rubinstein E, Ezra E, et al: Disc space infecrioB

and vertebral osteomyelitis as a complication of percutaneous
lateral discectomy. din Orthop 225:234-237, 1987.

62- Dall BE, Rowe DE, Odette WG, Batts DH: Postopcratm:

discitis. Diagnosis and management, din Orthop 224:138-

146, 1987.

63. Cloward RB: The anterior approach for removal of raptmed

cervical disks. J Neurosurg 15:602-617, 1958.

64. Smith GW, Robinson RA: The treatment of cenam cemedi-

spine disorders by anterior removal of the iniervBletaal Sac
and interbody fusion. J Hone Jt Surg 40/1:607-624. 1958.

65. Robinson RA, Smith GW: Anterolateral cervical disc funcol

and interbody fusion for cervical disc syndrome- Butt Ja6»
Hopk Hosp 96:223-224, 1955.

66. Hedge S, Staas WE Jr: Thoracic disc bermation and spool

cord injury. Am J Phys Med Rehab 167:228-229, 1988.

67. Perot PL Jr, Munro DD: Transthoracic removal of midlinc

thoracic disc protrusions causing spinal cord compression. J
Neurosurg 31:452-458, 1969.

68. Ransohoff J, Spencer F, Siew F, Gage L: Transthoracic re-

moval of thoracic disc: Report of three cases. J Neurosurg

31:459-461, 1969.

69. Hulme A: The surgical approach to thoracic intervertebral disc

protrusions. J Neural Neurosurg Psychiatr 23:133-137, 1960.

70. Bohlman HH, Zdeblick TA: Anterior excision of hemiatt

discs. / Bone Jt Surg 70A: 1038-1047, 1989. <

71. Lonstein JE: Post laminectomy kyphosis. din Orthop 128:93—"

100,1977.

72. Lonstein JE: Post laminectomy kyphosis, in Chou SN, Seljes-

kog RL (eds): Spinal Deformities and Neurological Dysfunc-
tion. New York, Raven Press, 1978, pp 53-63.

73. Sim FH, Svien HJ, Bickel WH, James JM: Swan-neck defor-

mity following extensive cervical laminectomy. J Bone Jt Surg
5&4:564-580, 1974.

74. Yasuoka S. Peterson HA, Laws ER Jr, MacCarty CS: Patho-

gBBsis and prophylaxis of postlaminectomy deformity of the

fj—e after multiple level laminectomy: Difference between

dBldreB aad a&ilts. Neurosurgery 9:145-152, 1981.

75- Y—uka S, Peteisoo HA. MacCarty CS: Incidence of spinal

>,x!itoa«* deSssasay after multilevel laminectomy in children and
•Jol&.JJfalM—^ 57:441-145, 1982.

%. Ofe——s K, UMte Y. Sttzald K: Suspension Laminotomy: A

ark farzica^ .iBdiKpe fix compiEssion myclopathy. Neuro-

»»2l^SM187,l«7-

77. isteda Y. Sczaki K, Otamxi K. a al: Critical analysis of

extensive lanuaeciomy. .VMOOWV 24:215-224. 1989.

78. Sieffee AD. Biscup RS. Silfcc—sia DJ: S^srnenui spine plates

with pedicle screw fixaooB: A new iBternal feuooo device for
disorders of the lumbar and thoraco lumbar spine. CIm Orthop
203:45-53, 1986.

79. Steffee AD, Sitkowski DJ: Posterior lumbar inlcrtiody fusion

and plates, din Orthop 227:99-102, 1988.

80. Wiltse LL: Classification and treatment of spondylolisthesis, in

Evarts CM (ed): Surgery of the Musculoskeletal System. New
York, Churchill Livingstone, chap 19, pp 411^)-25.

D STUDY QUESTIONS

I. A 26-year-old policeman who has recently been ap-
pointed to the force is seen because of severe pafn in the
right lower extremity. The patient gives a history of having
had sudden onset of lumbar back pain when helping to lift a
refrigerator, while cleaning out his garage 2 years earlier.
The pain persisted for 2 weeks then subsided.

He had two other occurrences of localized pain, radiating

into the right hip in the interim, each resolving when he
went to bed for 2 days. The episodes occurred while he was
getting out of his automobile.

The latest episode of pain happened when he was taking

calisthenics in training for his new position on the police
force. On examination, the patient had hypalgesia over the
dorsum of the foot with sensation to pinprick becoming
normal at about the site of the metatarsal of the third toe.
Knee and ankle jerks were normal but the patient dragged
his right foot when he walked, and there was weakness of
dorsiflexion of the right foot and some atrophy of the
intrinsic muscles of the right foot.

1. What is the most likely diagnosis? 2. What studies, if

any, should be obtained? 3. What treatment should be ini-
tiated? 4. Should surgery be considered? If so, when?
5. What might one expect to find on nerve conduction

studies? On EMG the day after acute onset of pain? Two
weeks later?

II. A 42-year-old housewife is referred because of pain in
the neck and left upper extremity. The pain has been pro-
gressive for 6 months. The pain usually improves, although
it is not absent when she gets up in the morning. It becomes
worse as the day goes on. It is made much worse when she
drives, especially as she turns her head. Indeed, she is
unable to look behind her. Pain is exacerbated by coughing.

On examination, there is tenderness on palpation of the

lateral surface of the neck. The neck is held quite straight.
There is atrophy and weakness of the left biceps muscle, and
the biceps reflex is absent, as is the radial periosteal reflex.
There is hypalgesia over the thumb and index finger.

1. What is the most likely anatomical diagnosis? 2. What

might one expect to see on plain radiographs of the neck?
3. What treatment(s) might be considered? 4. What other
studies might be considered? 5. What might one expect to
see on an EMG when the patient is seen first? Why?

III. A 48-year-old male laborer is seen because of progres-

sive difficulty walking, which has worsened over the 3
months prior to his visit.

On examination, the patient has good strength in the upper

and lower extremities. Deep tendon reflexes at the biceps
and radial-periosteal sties are normal, but the triceps reflexes
are quite fast. Deep tendon reflexes at the knees and ankles
are brisk (4+), and clonus is present at each of these sites.
Vibratory and position senses are slightly reduced in the
lower extremities. The patient denies pain throughout the

examination.

1. Where might a lesion be localized? 2. What diagnoses

should be considered? 3. An MRI demonstrates a narrow
spinal canal in the cervical area and impingement on the
cord by slightly protruding disks at C3-C4, C4-C5, and
C5-C6. What surgical treatments might be considered?
4. Why is this patient not complaining of pain? 5. What
might one expect to be accomplished by surgery insofar as
neurological disability is concerned?

TV. A 60-year-old postman has to stop working because of

back pain and pain in the legs when he walks. While he has
localized back pain at all times, the pain is much worse
when he ambulates. Both the back and leg pain are much
improved when fee patient sits or lies down for 15 to 20
min. He always feels more comfortable when sitting in a
flexed position.

Neurological examination is normal. Pulses in both lower

extremities are normal. Plain x-rays of the lumbar spine
demonstrate loss of lordosis on the lateral views and a mild

CHAPTEr

scoliosis with concavity to the left on frontal views. T-: ;
are degenerative changes at every level, most marke;

L4-L5, with large osteophytes at that level.

1. What diagnoses should be entertained? 2. What further

studies should be considered? 3. Assuming a myeloerasr
shows failure of the contrast media to go below L4 when the
patient is upright and that changes are indicative of extr;
dural compression from anteriorly and laterally, what surg -
cal therapy might be considered? 4. What types of stabiliy-:-
tion might be considered? 5. Assuming that the patient hac
x-rays made 10 years earlier which show no evidence of
scoliosis, what might be some explanations for the scoliosis.'

V. A 35-year-old obese female nurse experiences mid-
thoracic back pain after lifting a patient. Over a period of ?
months, the pain begins to radiate around the chest into the
upper abdomen. She develops weakness and mild spasticir.
of her legs and decreased sensation to pinprick over the
lower abdomen and lower extremities.

Plain radiographs of the thoracic spine reveal hypertrophic

changes at the T8-T9 level and gas in the intervertebral disk
at that level.

1. What diagnoses should be entertained? 2. What inves-

tigations might be carried out? 3. Assuming a midline her-
niated intervertebral disk is demonstrated at the T8-T9 level.
how might it be treated? 4. What might explain the hyper-
trophic changes in the bone surrounding the disk space?
5. What nerve roots might be affected?