Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 73 pot

a b cCase Introduction Female patient with a 22-year history of low back pain and a de novo scoliosis primary degenerative scoliosis exemplify-ing the natural history of this scoliosis t

a b c

Case Introduction

Female patient with a 22-year history of low back pain and a de novo scoliosis (primary degenerative scoliosis) exemplify-ing the natural history of this scoliosis type The patient first sought medical help for low back pain at the age of 33 years The radiograph exhibited a short left-convex lumbar scoliosis (8°), which in retrospect can be attributed to a disc degen-eration of L3/4 (disc space narrowing) and an asymmetry at the L2/3 level (a) At that time, the patient was treated with NSAIDs and physiotherapy with some improvement However, she was never really pain-free When she was 50 years old, she had increasing back pain with radiating pain mostly into the right anterior thigh In the meantime, the patient entered menopause, and the curve now measured a Cobb angle of 25° with a lateral translation and rotation of L3 toward the left side (b) Five years later the curve measured 40°, an average 3° curve increase per year The curve was now clearly identifiable as a short, left-convex curve from L2–L4 (end vertebrae) (c) The overall frontal balance was still more

or less in equilibrium However, the sagittal profile converted toward a lumbar kyphosis The patient now complained not only about difficulty of controlling back pain, but also about classical claudication symptoms when walking

400 – 500 m The pain disappeared when resting The back pain was much less when resting in bed, but increased when standing up in the vertical position The translation/rotation of the apical vertebra L3 had also increased compared to

5 years previously This curve demonstrates a truly progressive degenerative de novo adult scoliosis, which ended with the complete set of symptoms and signs which finally necessitate surgery This process involves a mechanical deteriora-tion of the lumbar spine, which expresses itself in clinical signs and symptoms related to instability, mostly axial-vertical instability with some translational component, central canal and/or foraminal neurocompression, fatigue of unbalanced paravertebral muscles and finally curve progression The understanding of the natural history and behavior of such a pri-mary degenerative scoliotic curve may help to make a decision for or against relatively early surgery In the case of early surgery, the intervention may be more limited and simple, both for the patient and the surgeon.

The prevalence

of degenerative scoliosis

is increasing

Degenerative scoliosis seems to be becoming more frequent in an increasingly aging society for several reasons, which may include the more aggressive and pre-cise diagnosis than was possible 20 years ago, a different perception of pain in a modern urbanized society, and the desire of a large component of our society to be active in sports and to pursue leisure activities also after retirement It seems,

how-ever, that degenerative scoliosis is not a characteristic disease of industrialized

society, since the same pathology can be observed in other, less developed

socie-ties [7]

Pathogenesis

Primary (de novo) degenerative scoliosis results from segmental degeneration

Primary degenerative adult scoliosis, specifically in the lumbar spine, is

charac-terized by a quite uniform pathomorphology and pathomechanism [1] The

asymmetric degeneration of the disc and/or the facet joint leads to an

asymmet-ric loading of the spinal segment and consequently of a whole spinal area This

again leads to an asymmetric deformity, for example scoliosis and/or kyphosis

[6, 14] Such a deformity again triggers asymmetric degeneration and induces

asymmetric loading, creating a vicious circle ( Fig 1a) The destruction of discs,

facet joints and joint capsules usually ends in some form of uni- or

multisegmen-tal sagitmultisegmen-tal and/or fronmultisegmen-tal latent or obvious instability There may not only be a

spondylolisthesis, meaning a slip in the sagittal plane, but also translational

dis-locations in the frontal plane or rather three-dimensionally when the instability

expresses itself in a rotational dislocation [15]

The biological reaction to an unstable joint or, in the case of the spine, an

unstable segment, is the formation of osteophytes at the facet joint

(spondylart-hritis), and at the vertebral endplates (spondylosis), both contributing to the

increasing narrowing of the spinal canal together with the hypertrophy and

calci-fication of the ligamentum flavum and joint capsules, creating central and

reces-sal spinal stenosis (Fig 2) The pathomorphological and pathomechanical

rela-tionship directly relates to the clinical presentation of an adult degenerative

scoli-The progressive degenera-tion and deformity often leads to central and foraminal stenosis

osis (Fig 1b) The osteophytes of the facet joints and the spondylotic osteophytes,

however, may not sufficiently stabilize a diseased spinal segment Such a

condi-tion leads to a dynamic, mostly foraminal stenosis with radicular pain or

claudi-cation type pain, specifically when the spine is loaded vertically

Figure 1 Pathogenesis of degenerative scoliosis

aDegenerative scoliosis results from a close interaction of asymmetric loading, degeneration and deformity.bThe

clini-cal symptoms are closely related to the pathomorphology.

Figure 2 Degenerative changes

Deformity and spinal imbalance lead to secondary degeneration, i.e., facet joint arthrosis (hypertrophy), disc degenera-tion, spondylosis spurs and osteophytes, and calcified ligaments as a biological reaction with the goal of stabilizing the spine As a consequence spinal stenosis develops When decompression is performed destabilization results.

Classification

Degenerative scoliosis forms a major part of the adult scoliosis group This group comprises a wide spectrum of different pathologies, which may look very similar

at the end-stage, when many patients are seeking help from a spine surgeon for the first time [15] These patients usually have a long history of back pain and spi-nal discomfort and have undergone all the possible symptomatic treatment modalities such as exercise, acupuncture, braces and other complementary med-ical measures as well as pain medication

There is no established classification system for degenerative scoliosis [1, 7] However, the most important distinction is between primary degenerative scoli-osis and secondary degenerative scoliscoli-osis (Table 1)

Table 1 Classification of degenerative scoliosis

Primary (de novo) degenerative scoliosis Secondary degenerative scoliosis

) develops de novo after skeletal maturity ) results from degenerative alterations of

curves existing prior to skeletal maturity

Classification systems

or degenerative idiopathic

scoliosis is inadequate to

describe de novo scoliosis

Several attempts have been made to elucidate some systematic structure in this kind of pathology A classification on the basis of the curve type, very much as in the idiopathic scoliosis classification by Lenke [21], has been proposed This clas-sification may be able to cover the adult idiopathic scoliosis group with second-ary degeneration but is not necessarily adequate for the primsecond-ary degenerative scoliosis type Another attempt at classification has recently been presented by Schwab et al [13, 27], who distinguished three groups based on measurements of the endplate obliquity of L3 in the frontal plane, and of the lumbar lordosis mea-sured between the L1 and S1 superior endplates in the sagittal plane of a standard X-ray

This is obviously a classification which can be applied solely to primary

degener-ative lumbar scoliosis The three distinct types with increasing severity from

Type 1 to Type 3 are:

) Type 1 – lordosis > 55°, L3 obliquity < 15°

) Type 2 – lordosis 35 – 55°, L3 obliquity 15 – 25°

) Type 3 – lordosis < 35°, L3 obliquity > 25°

The interesting characteristic of this classification is the attempt to correlate the

objective radiological findings with the self-reported pain and disability

We have recently proposed an etiological classification which basically

distin-guishes three types, Type 3 being subdivided into two subtypes [1]:

) Type 1 – primary degenerative scoliosis (“de novo” form), mostly located in

the lumbar or thoracolumbar spine

) Type 2 – progressive idiopathic scoliosis in adult life of the thoracic,

thora-columbar and/or lumbar spine A rough distinction can be made between

adult idiopathic scoliosis in patients less than 40 years of age and those aged

over 40 years

) Type 3 – secondary degenerative scoliosis comprising:

Subtype 3a: degeneration of secondary curves following idiopathic or other

forms of scoliosis or occurring in the context of a pelvic

obliq-uity due to a leg length discrepancy, hip pathology or a

lumbo-sacral transitional anomaly, mostly located in the

thoracolum-bar, lumbar or lumbosacral spine

Subtype 3b: scoliosis secondary to metabolic disease (mostly osteoporosis)

[18] combined with asymmetric arthritic disease and/or

verte-bral fractures

There is no classification gold standard

The clinical entity of an adult degenerative scoliosis can indeed be present since

childhood or adolescence and can become progressive and/or symptomatic only

in adult life [5, 24], or a scoliosis may appear de novo in adult life only without

any precedence in early life In this chapter we deal predominantly with Type 1

scoliosis, partially with Type 3a and only marginally with Type 2 The chapter is

not closed over the classification issue, since an ideal classification must be

sim-ple, easy to apply and imply treatment options that are designed to correlate well

with the clinical picture and outcome

Clinical Presentation

History

Patients with adult degenerative scoliosis seek medical help for four major

rea-sons [1, 6, 7, 16, 23], which also present as cardinal symptoms:

) back pain

) claudication symptoms and/or radicular pain

) neurological deficits

) increasing deformity (curve progression)

Cosmesis does not have the same significance as in adolescent scoliosis;

neverthe-less recent studies show that the self-perception of scoliotic adult patients plays an

important role in a health assessment analysis [13] The clinical picture as

out-lined above can be substantially aggravated by concomitant osteoporosis [18]. Patients have a long history

of back pain before they complain of claudication symptoms

Usually these patients have a long history of back pain and only in a second

stage do they complain about leg pain, claudication symptoms and difficulty, for

instance, climbing or descending stairs Most of these patients experience pain

when in an upright position under an axial load and are more or less pain free when lying down Most of them report loss of height over time and some patients have increased pain when turning in bed or twisting during physical activity, which relates to a certain instability of the deformed and mechanically weakened spine

Back Pain

Back pain is often related to instability

Back pain is the most frequent clinical problem of adult scoliosis, and presents

itself with a multiform mosaic of symptoms Back pain at the site of the curve can

be localized either at the apex or in its concavity, and facet joint pain can be local-ized in the counter curve from below the curve to above the curve [32, 33] Back pain can be combined with radicular leg pain, and can be the expression of mus-cular fatigue or of a real mechanical instability Unbalanced, overloaded and stressed paravertebral back muscles may become very sore and in return will not contribute to balance the muscle play, consequently becoming part of a vicious circle This is especially true when the lumbar curve is accompanied by the loss

of lumbar lordosis [10, 15, 20] This muscular pain is rather diffuse, is distributed over the lower back and is often permanent at the insertion of the muscle tendons

at the iliac crest, sacrum, os coccyx and bony process of the spine The back pain can be constant and non-specific, which is a bad prognostic sign regarding the treatment outcome The pain, however, can be present only when the patient is upright, especially when standing and sitting, presenting itself as a so-called Patients often complain

of axial back pain due to

segmental instability

axial pain or only during certain movements or physical activities, pointing

rather to a mechanical unstable segment or a whole spinal region Patients often indicate that they can control their pain well when lying down flat or on their side and when the axial load is taken off the spine

Spinal Claudication Claudication is the second most important symptom of adult degenerative

scoli-osis and may express itself as:

) radicular claudication ) central claudication Central, lateral and recess

stenosis are frequent

The symptoms become worse when standing or walking The patient can have a true radicular pain due to a localized compression or root traction The roots are compressed not necessarily on the concave side due to a narrow foramen, but

often on the convex side, rather expressing a dynamic overstretch of the root [20,

32, 33] There may, however, be a single or multilevel spinal stenosis which can be central or more in the lateral recess creating claudication symptoms Root com-pressions can occur at the bottom of the curve or at the transition to the sacrum and can be linked to a hypermobility of an overloaded bottom segment, espe-cially in cases of stiff curves Short lumbosacral or lumbar curves as counter curves to long fused thoracolumbar scoliosis often show a severe spinal stenosis

at the transition from the stiff upper spinal area to the lower lumbosacral area

Neurological Compromise

Neurological deficits

occur late

Neurological deficit is the third most important clinical presentation and may include individual roots, several roots or the whole cauda equina with apparent bladder and rectal sphincter problems An objective neurological deficit, how-ever, is rare and when present is due to a significantly compressed space in the spinal canal with a relatively acute aggravation and decompensation A

seques-Figure 3 Neurological compromise

Sequestrated disc with neurological radicular deficit in a

severely degenerated lumbar scoliosis in a 79-year-old frail

female patient at the concave side of level L4/5 Since the

decompression needed to be done within the curve close

to the apex, an additional stabilization of the L4/5 joint has

been done in order to avoid a possible progression of the

curve and the deterioration of the neurological findings.

tered or calcified disc within the curve may be the cause of such an acute

neuro-logical deficit It can be accentuated or only become clinically relevant due to a

latent or obvious segmental instability (Fig 3)

Increasing Deformity

Osteoporosis accelerates curve progression

Finally, increasing deformity due to curve progression is a relevant sign of

degen-erative scoliosis [23, 24] Curve progression may be an issue from the moment

the curve occurs in younger age It may, however, only become relevant when the

curve has reached a certain size and/or when osteoporotic asymmetric collapse

may contribute significantly to the curve [18] Once a curve has reached a certain

extent of curve degrees, the progression will automatically follow due to the axial

Larger curves tend to progress faster than small curves for biomechanical reasons

mechanical overload of individual facet joints and/or osteoporotic vertebral

bodies The progression of the curve may well be an indication for surgical

treat-ment Surgeons need to be aware of the amount of aggravation which may occur

when no surgery is done The increasing age of patients should be borne in mind

along with all the medical consequences which automatically increase the risk of

a surgical intervention [25, 26, 29, 31] Therefore, a surgical intervention may

occasionally be indicated in order to avoid further progression and degeneration

in a patient with potential medical risks

Physical Findings

The clinical examination usually easily demonstrates a patient with a deformed

back or trunk once the curve has progressed beyond about 35° Examination

with the patient in the standing position may reveal:

) an oblique pelvis

) a lumbar or thoracic hump

) an unequal shoulder level

) an asymmetric lumbar triangle

) loss of lordosis (flatback)

) loss of sagittal and coronal balance

The hump is often already visible in the standing position but more so when the

patient is bending forward A counter rib hump is an expression of a primary or

compensatory thoracic or thoracolumbar scoliosis Severely deformed patients

may stand with flexed knees to shift their anterior trunk in balance back into a Note sagittal and coronal

imbalance position over the center of the pelvis This out-of-balance position in the sagittal

plane is due to the lumbar flat back or kyphosis Usually, patients are still quite mobile in spite of a radiologically relatively stiff curve The lumbar triangle is usually accentuated on the concave side and flat on the convex side The side bending as well as flexion and extension of the lumbar curve is usually very lim-ited in progressed curves Neurological deficits are rare and can vary from some sensory radicular signs to paraparesis due to a complete stenosis of the spinal canal or rarely a multilevel radicular syndrome Reflex anomalies may occur in isolation or in combination with other neurological deficits Sometimes the dis-tinct neurological deficit has to be correlated with the target muscles of the spe-cific lumbar roots

Diagnostic Work-up

The relevant diagnostic measures in patients with degenerative scoliosis consist

of both imaging studies and interventional radiological studies Laboratory tests are only necessary as a preoperative evaluation for patients planned to undergo surgery

Imaging Studies

Very often the whole armentarium of imaging studies is necessary to understand the complexity of a curve and specifically, if present, the concomitant neurologi-cal signs or deficits

Standard Radiographs

Full body standing radiographs are indispensable

Whole spine X-rays where the center of the skull and the pelvis are visible are necessary in both the frontal and the lateral planes Spot views predominantly of

the lumbar spine are necessary to analyze the affection by the scoliosis in the

dif-ferent segments Oblique radiographs are helpful in exploring facet joint alter-ations and foramina Functional views including side bending as well as flexion/ extension films are necessary Functional radiographs are better performed with

the patient in the supine position than under axial load If performed with the patient in the supine position, there is a need for the physician to attend the X-ray capture of the patient On standard radiographs there may be clues [14, 15] as to whether a scoliosis is truly a primary degenerative scoliosis or rather a secondary Radiographs sometimes

exhibit clues to the etiology

of the curve (primary

vs secondary)

degenerative scoliosis (Fig 4) It is important to look at earlier radiographs to

understand the natural history and therefore the etiology of the curve The sagit-tal contour of the lumbar spine is important in terms of pain and outcome since

curves with a loss of lordosis < 25° are usually painful and have a more complex treatment requirement [13]

Magnetic Resonance Imaging

Magnetic resonance imaging is the imaging modality of choice to explore neural

compromise and disc degeneration Coronal views are very helpful in assessing

neural compromise in relation to the curve However, degenerative scoliosis is often very polymorphic with MRI due to the complex pathology, parts of which may still be difficult to understand and may leave us uncertain as to what the leading pathology is For example, deformity may be interpreted on one of the MRI cuts as spinal stenosis since the whole deformity is not in the same plane; however, the patient has no signs of spinal stenosis at all

a b c d

Figure 4 Primary and secondary degenerative scoliosis

a,bSecondary degenerative scoliosis on the basis of an idiopathic scoliosis is usually more strongly expressed,c,dless

osteoporotic and longer than a primary degenerative scoliosis In both end stages there are translational and rotational

dislocations of individual vertebrae.

Computed Tomography

Computed tomography with or without a myelogram is the diagnostic imaging

method of choice in the case of diagnostic uncertainties related to the

three-dimensional curve pattern, precise localization of root compressions and their

correlation with clinical findings

Interventional Radiological Procedure

In the context of the evaluation of the pain source, spinal injection studies (see

Chapter 10) are especially helpful since their findings may change the

therapeu-tic approach [1, 20, 33] Helpful interventional studies are:

) provocative discography

) facet joint blocks

) nerve root blocks

) epidural blocks

Injection studies are sometimes helpful in identifying the pain source

It is important, for instance in lumbar curves, to find out whether the pain occurs

within the curve or below the main curve, or whether it usually involves L4/5 and

L5/S1, or rarely whether it is above the curve at the thoracolumbar junction

Since the pain can be generated in one or several segments, it is recommended to

perform the discograms or the facet blocks sequentially in order to isolate the

really painful segment In addition, discography can be used as a pain

provoca-tion test as well as a pain eliminaprovoca-tion test (i.e., injecting local anesthestic possibly

with some steroids) The test is double positive when pain is first elicited during

injection and disappears shortly after the injection The selective use of epidural

blocks at stenotic levels or selective nerve root blocks is another helpful tool to

identify the level clinically relevant to the symptomatology on the one hand and

as a therapeutic tool on the other hand in case surgery is not feasible or is decided

to be delayed

Additional Diagnostic Tools

A temporary immobilization

cast can reveal mechanical

back pain

If, despite all of these tests, the pain remains unexplained, it may in rare cases be

helpful to put on a temporary immobilization cast in the form of a

thoracolum-bar orthosis (TLO) or thoracolumbosacral orthosis (TLSO) to see whether an overall stabilization and fusion of the whole scoliotic spinal area could be benefi-cial for the patient, specifically in cases of an overall tendency of the spine to stat-ically collapse

In elderly people with degenerative scoliosis, with plain predominant symp-toms of claudication, leg pain and multilevel stenotic segments in the imaging

studies, neurophysiologic studies (see Chapter 12) may be helpful to identify the level responsible for the clinical presentation A clear topographic diagnosis would certainly help to minimize the surgery in these patients

Osteodensitometry (DEXA) is indicated whenever there is a suspicion of

oste-oporosis because of the implications with regard to curve progression and poten-tial spinal fixation

Non-operative Treatment

The indication for or against surgery and, more specifically, the type of surgery

to be performed involves complex decision-making [1] Certainly, surgery is only

an option when the non-surgical measures have no effect or do not have the pros-pect of any relevant long-term help

The general objectives of treatment derive from the cardinal symptoms of degenerative scoliosis (Table 2):

Table 2 General objectives of treatment

) eliminate spinal claudication ) prevent curve progression

The non-surgical treatment options basically consist of:

) non-steroid anti-inflammatory drugs (NSAIDs) ) muscular relaxation

) pain medication ) muscle exercises

Figure 5 Therapeutic

options

) gentle traction (in selected cases)

) spinal injection studies

) orthosis

Manipulations should be avoided

Manipulations and physical activation should be avoided because they may

increase the pain Therapeutic epidural and selective nerve root blocks as well as

facet joint blocks may help to control the pain temporarily Sometimes, a

well-fit-ted brace to support the painful spine area may be necessary [23]

In order to plan the most promising therapeutic approach for each patient, a

clear understanding of the prominent symptoms or clinical signs is mandatory

The symptoms and clinical signs can be addressed by various therapeutic

treat-ment modalities (Fig 5)

Operative Treatment

The decision about treatment approach and type of surgery is complex

A surgical approach to degenerative adult scoliosis is obviously complex in terms

of decision-making, e.g., ascertaining the surgical indication and choosing the

patient and the procedure appropriately

The technical difficulties, however, are equally relevant The aggravating factors

and difficulties with this type of surgery are manifold Curve magnitude and age

of the patient are, for instance, significant predictors of curve flexibility [2, 4, 29,

31] The understanding of this association allows the treatment options over time

to be better addressed The possible surgical technique can be divided into:

) posterior procedures

) anterior procedures

) combined procedures

In all these procedures, a simple decompression or stabilization with pedicle

screws [2, 4, 8, 22, 28] can be done alone or in combination In some cases,

addi-tional correction may be considered, either by clearly defined osteotomies or by

sequential segmental corrections through instrumentation This is particularly

of interest in combined sagittal/frontal rigid deformities

The goals of the various treatments depending on curve type are summarized

inTable 3.

Table 3 Surgical treatment options

Scoliosis type Decompression Correction Posterior stabilization

and fusion

Anterior stabiliza-tion and fusion

Primary (de novo)

degenerative

scoli-osis (lumbar,

thora-columbar)

) rarely laminectomy, often necessary by laminotomy, en-largement of lateral recess and foramen

) not a primary objec-tive (depends on pain pattern and spinal balance)

) usually posterior stabili-zation and posterolat-eral fusion sufficient.

Occasionally selectively combined with PLIF in younger patients.

) usually not neces-sary

Secondary lumbar

or thoracolumbar

degenerative

sco-liosis (idiopathic

curves)

) often necessary in elderly patients with

a long-lasting his-tory, not so much in younger patients

) in younger patients correction possible

) usually posterior stabili-zation and posterolat-eral fusion sufficient.

Occasionally PLIF in younger patients

) usually not neces-sary As stand alone procedure possible in youn-ger patients

cave thoracic curve:

overall balance man-datory

Progressing

idio-pathic curve in

patients younger

than 40 years

(tho-racolumbar curves)

) rarely necessary ) younger patients:

cor-rection and balanced spine desired Com-bined anterior/poste-rior release often nec-essary

) posterior pedicle fixa-tion posterolateral fusion, pedicle based

) anterior stand alone surgery at the thoracolum-bar junction pos-sible