Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 74 docx

Whether a degenerative scoliosis should be corrected or not, depends on sev-eral factors: age cardinal symptoms coronal balance sagittal alignment curve rigidity rigidity of the ad

Decompression Procedure

Decompression alone may

result in curve compression

The type of decompression used depends on the extent of necessary decompres-sion There is the option to decompress microsurgically the lateral recess and/or the foramen or to perform a more extensive canal enlargement by laminotomy, hemilaminectomy, or laminectomy to address the crucial compressive lesion If two adjacent segments need to be decompressed, a laminectomy can be consid-ered, specifically when a surgical stabilization is foreseen Whether maintenance

of the integrity of the vertebral arches is necessary in a stabilized and fused spine

is not clear, but it may prevent scarring of the dural sac.

Besides the direct decompression as mentioned above, there is the possibility

of indirect decompression occurring on correction of deformity and

realign-ment of the spine The older the patient and the longer lasting the degenerative scoliosis is, the more carefully this concept has to be applied Adhesion of the dural sac due to scarring between the dura and the hypertrophied ligamentum flavum and facet joint capsules, and sometimes directly to the bone, may induce traction and/or compression of neural elements with consecutive neurological The pros and cons of direct

of indirect decompressions

must be carefully weighed

deficit The benefits of correction of the curve therefore have to be carefully weighed against the direct decompression The idea that osteophytes and bony spurs may disappear over time in a stabilized and fused segment may leave the patient with sometimes persistent symptoms for quite a long time The recom-mendation is to explore the crucial roots after a corrective measure by small fen-estration of the spinal canal in order not to miss a possible persistent compres-sion or traction of a neural element.

Correction Procedures

Sagittal balance

is most important

Whether or not a degenerative scoliosis should be corrected remains a crucial and complex question The treatment of a degenerative scoliosis has different goals than the treatment of adolescent scoliosis While in the latter the goal is pre-vention of curve progression and cosmetic improvement, degenerative scoliosis requires the relief of back and leg as well as claudication symptoms Correction has to address spinal imbalance, which is mainly in the sagittal plane [1].

Whether a degenerative scoliosis should be corrected or not, depends on sev-eral factors:

) age ) cardinal symptoms ) coronal balance ) sagittal alignment ) curve rigidity ) rigidity of the adjacent spine

Age

The need for curve

correc-tion decreases with age

The older the patient, the less necessity there is to correct the deformity Correc-tion may induce diffuse back pain in elderly patients, which may be due to the age-related inability to adapt to a new muscle balance A correction may be nec-essary if there is a clear frontal imbalance The correction may, however, rather consist in a localized osteotomy than in an overall correction of the curve An additional sagittal imbalance needs to be corrected in most cases of chronic back pain in the context of a degenerative deformity [13, 20] The correction has to reach the plumb line falling from the projection of the outer auricular canal onto the femoral head.

Cardinal Symptoms and Imbalance

Curve correction is indicated

in the presence of significant coronal or sagittal imbalance

A curve correction is indicated in patients with chronic back pain without a

localized pathomorphology (e.g., painful facet joints) and a clear coronally and

sagittally unbalanced spine In younger patients, treatment consists of an

overall curve correction A localized osteotomy is more appropriate in elderly

patients.

Curve Rigidity

Rigid severe curves require anterior release

In a completely rigid curve, specifically in elderly patients, a correction usually is

not necessary except if the back pain is related to the imbalance of the curve The

correction of a rigid curve may be achieved either by a localized corrective

osteo-tomy (transpedicular reduction osteoosteo-tomy) preferentially in elderly patients, or

alternatively by a multilevel release and mobilization of the facet joints with

oste-otomies in the joints and an overall correction through reduction of the

mobi-lized spine to a pre-contoured rod A rigid thoracolumbar curve > 70° usually

needs a combined approach [19, 20] (Case Study 1).

Rigidity of the Adjacent Spine

Postoperative coronal imbalance is a risk

In the case of a lumbar or thoracolumbar degenerative curve which is adjacent to

a rigid (fused or ankylosed) idiopathic thoracic curve, any correction of the

lum-bar spine has to be well thought through Because of the rigid thoracic curve, the

spine may fall completely out of balance following a lumbar correction In

youn-ger patients rarely it may be necessary to add a mobilizing osteotomy to the

upper curve to effect a necessary lumbar correction.

Surgical Techniques

The armentarium of surgical techniques for the correction of degenerative

scoli-osis consists of:

) posterior release

) anterior release

) wedge osteotomies

) transpedicular reduction osteotomies

Posterior release can be achieved through mobilization and osteotomies of the

facet joints This procedure may be accompanied by an anterior release when

sig-nificant osteophytes and intervertebral disc calcifications exist If posterior

release and facet joint osteotomies are not sufficient, wedge osteotomies of the

arches (Fig 6) may provide further correction For a significant localized

correc-tion, a bilateral or unilateral transpedicular reduction osteotomy (Fig 7) may be

necessary at one, two or three levels The correction of the lordosis in severe flat

back syndrome can best be achieved by a pedicular reduction osteotomy when an

anterior and posterior release is not sufficient.

In all the above-mentioned methods a posterior pedicle-based

instru-mentation is necessary [2, 8, 12, 22, 32] The correction is done by contouring

the rod in the desired shape and by pulling and/or pushing the pedicle

anchorage toward the rod One possibility is to adapt the rod to the curve – in

the lumbar spine on the convex side – and to rotate the rod, which is inserted

in the pedicle anchorage (screws or pedicle-based hook screws) into the

lor-dosis An alternative is to bend and adapt the rod in situ to the best possible

contour.

Degenerative Scoliosis Chapter 26 725

a b

Figure 6 Smith-Peterson arch osteotomy

This technique creates lordosis and is usually applied to one or multiple levels.aThe interspinous ligament and the adjoining spinous process are resected with a rongeur and the interlaminar ligamentum flavum is removed in the mid-line, from where lateral osteotomies are carried out bilaterally, through the facet joints in the direction of the interspinal foramina.bThese osteotomies are directed laterocranially, at an angle of 30 – 40 degrees to the horizontal The desired slot width of 5 – 7 mm is obtained by using a suitably wide rongeur If there is a lateral overhang, the osteotomies are made slightly larger on the convex side The osteotomy gap is closed by a tension banding pedicular fixation one or two levels above or below With one single osteotomy approximately 10 degrees of correction can be achieved

Unilateral cage insertion

facilitates segmental

correction

A further methodology to achieve specifically short distance correction in the lumbar spine without performing osteotomies consists of complete mobilization

of a deformed segment with complete removal of the disc through either an

ante-rior or a posteante-rior approach and using a unilateral cage or tricortical bone graft

by either an anterior lumbar interbody fusion (ALIF) or a posterior lumbar inter-body fusion (PLIF) procedure.

In the case of a uniquely posterior procedure, a posterolateral intertransverse fusion is done by autologous bone graft, either collected from laminar bone dur-ing the decompression procedure and/or the iliac crest, or by an allogeneic bone graft from a bone bank or a combination of autologous/allogeneic bone, which can still be augmented by, e.g., granular tricalciumphosphate.

An isolated anterior release and stabilization is seldom applicable and may work in younger patients at the thoracolumbar junction by sparing segments from inclusion into the fusion In cases where anterior surgery is done, it is mostly a combined front and back procedure [19].

Avoid fusion to the sacrum

in young patients

Debate continues on the indications for a lumbosacral fusion Only general

recommendations can be given [9, 12, 30] In young patients with secondary degenerative scoliosis, it is better to omit L5/S1 from fusion whenever possible in order to prevent iliosacral joint degeneration or an early hip problem It is also usually preferable to stop at L4 in a lumbar curve whenever possible However, a fusion to the L5 vertebra is necessary when the condition of the L4/5 facet joint is poor (Case Study 1) This obviously leads to an overload of the L5/S1 segment However, it is difficult to predict the time when the secondary facet arthritis will occur, and possibly a good sagittal alignment will delay this substantially The

a b

Figure 7 Pedicle reduction osteotomy

aThe osteotomy is started by removing the posterior arch including the facet joints until only the pedicle stump at the

transition to the posterior wall of the vertebral body is left with also the transverse process removed.bThe pedicle stump

is then excavated continuously into the vertebral body, which is emptied by means of an “eggshell” procedure.cThe

remaining posterior bridge between the two wholes of the pedicle stumps is then resected by a large Kerrison rongeur

dThe created “empty” wedge is then closed under compression by means of a posterior pedicle-based tension banding

system

Add an interbody fusion when fusion to the sacrum

is intended

patient, however, needs to be informed that secondary surgery may become

nec-essary later [9, 12, 30] When fusion to the sacrum cannot be avoided, it is

important to add an interbody fusion to decrease the risk of a non-union This

can either be done by an anterior (ALIF) or a posterior (PLIF) approach (Case

Study 2).

Degenerative Scoliosis Chapter 26 727

a b c d

Case Study 1

A young female teacher presented with progressive

idio-pathic scoliosis At the age of 35 years the curve measured

62° (a) Three years later the curve had progressed to 75° (b)

With curve progression, the patient developed

incapacitat-ing back and leg pain and was unable to work The major

curve progression occurred during pregnancy All

conserva-tive treatment failed and the patient decided to undergo

surgery A left bending functional radiograph shows only

some correction of the curve (c) The patient presented with

lumbar kyphosis which needed to be addressed (d)

Com-bined anterior/posterior surgery was performed First, an

anterior release through a minimally invasive

thoracophreni-columbotomy from the left side was done and the

interver-tebral disc spaces of T12/L1, L1/L2, L2/L3 and L3/L4 were

released and filled with a hybrid of corticocancellous bone

combined with beta-tricalciumphosphate (q -TCP) for an

anterior fusion Second, for posterior release and facet joint

osteotomies, correction was done in conjunction with

recon-struction of the lumbar lordosis and a posterolateral fusion

from T9 to L5 Radiographs at 18 months follow-up show

res-toration of lumbar lordosis and coronal balance (e,f)

a b c d

Case Study 2

A 39-year-old female patient presented with incapacitating back pain due to a progression of adult idiopathic scoliosis

(Type 2) (a) There was no evidence of claudication symptoms or radicular pain Non-operative treatment did not result

in persistent pain relief The preoperative lateral radiograph shows a significant loss of lumbar lordosis (3°) (b)

The postoperative radiographs show a restoration of lordosis to 22° and circumferential fusion with PLIF at the

lumbosa-cral junction in order to avoid non-union Frontal correction of the scoliosis was satisfactory (c,d)

Recapitulation

Epidemiology. Primary degenerative scoliosis

de-velops de novo after skeletal maturity and needs to

be distinguished from the secondary degenerative

changes of a curve already present at the end of

growth The prevalence of scoliosis in patients

old-er than 50 years is about 6 % including both types.

Degenerative scoliosis is more prevalent in males

than in females The overall prevalence is increasing

due to the aging population.

Pathogenesis. Primary degenerative scoliosis results

from segmental instability and degeneration of

inter-vertebral discs and facet joints, often resulting in

ante-rior and lateral displacement The body counteracts

the instability by a thickening of the ligaments,

lum-bar spondylosis and facet joint hypertrophy causing

central and foraminal stenosis The clinical symptoms

closely relate to the pathomorphological alterations.

Secondary degenerative scoliosis results from

asym-metric loading and dysbalance of the spine.

Clinical presentation. The cardinal symptoms are

back pain, claudication symptoms, radicular pain,

neurological deficits and increasing deformity Back pain is often related to spinal instability Cosmetic aspects are not a predominant complaint in con-trast to adolescent scoliosis Claudication symp-toms are very frequent but neurological deficits ap-pear late The clinical assessment must focus on the

sagittal and coronal balance as well as on the

sagit-tal profile (flat back, thoracolumbar or lumbar ky-phosis) Concomitant osteoporosis must be as-sessed.

Diagnostic work-up. Standing whole body anterior and posterior radiographs are indispensable for a clear understanding of the curve and the etiology.

A differentiation of primary and secondary degen-erative scoliosis is difficult in advanced stages be-cause spinal rotation and lateral displacement can

be present in both types MRI is the imaging modal-ity of choice to show disc degeneration and neural compromise CT and combination with myelogra-phy are sometimes necessary to better demon-strate the three-dimensional character of the curve and neural impingement Provocative discography

Degenerative Scoliosis Chapter 26 729

as well as facet joints, nerve root and epidural

blocks often allow the identification of the source

of the pain Neurophysiologic studies and

osteo-densitometry are helpful in selected cases.

Treatment. Non-operative treatment consists of

NSAIDs, physiotherapy, spinal injection studies and

orthosis However, conservative treatment cannot

prevent progression of the curve The general

goals of surgery derive from the cardinal

symp-toms: resolution of back pain and claudication

symptoms, reversal of neurological deficits, and

correction of deformity or prevention of curve

pro-gression In elderly patients, decompression may

suffice if the main symptom is spinal stenosis Care

must be taken not to further destabilize the spine.

The correction procedures consist of anterior,

pos-terior or combined interventions The choice of the

technique depends on age, cardinal symptoms,

coronal balance, sagittal alignment, curve rigidity,

and rigidity of the adjacent spine In elderly patients, posterior release is sufficient to realign the

spine A severely rigid curve in young individuals

usually requires a combined anterior/posterior release When anterior and/or posterior release is

insufficient, wedge osteotomies or transpedicular reduction osteotomies are indicated to rebalance

the spine Posterior pedicle screw fixation is the standard fixation technique Posterolateral fusion with autograft, allograft or bone substitutes accom-panies spinal instrumentation in almost all cases Only in young individuals with short segmental curves is anterior release and instrumented fusion

advisable Sagittal and coronal rebalancing as well

as reshaping the sagittal contours (flat back) are crucial for a good outcome Fusion to the sacrum should be avoided whenever possible in young

individuals However, if fusion to the sacrum can-not be avoided, an interbody fusion is mandatory

to reduce the risk of non-union.

Key Articles

Aebi M ( 2005) The adult scoliosis Eur Spine J 14(10):925–948

A recent review article which allows for further reading

Bridwell KH ( 1996) Where to stop the fusion distally in adult scoliosis: L4, L5, or the sacrum? Instr Course Lect 45:101–7

This articles highlights the many aspects which must be weighed and discussed with the patient before deciding on a long fusion down to the middle or distal lumbar spine Out-come of surgery is crucially dependent on how well the different aspects are addressed by surgery

Grubb SA, Lipscomb HJ, Coonrad RW ( 1988) Degenerative adult onset scoliosis Spine 13:241–245

The authors reviewed 21 patients with the diagnosis of degenerative scoliosis This review shows that patients can de novo develop progressive scoliosis and loss of lumbar lordosis with a resulting flat back deformity These patients commonly present in the 6th decade

of life with predominant claudication symptoms but often lack the classic feature of relief

in a sitting posture The number of male and female patients was approximately equal Roentgenogram findings show a high angle deformity over a short number of spinal seg-ments and an absence of bony features associated with idiopathic scoliosis such as lateral vertebral wedging and alterations of the lamina

Grubb SA, Lipscomb HJ ( 1992) Diagnostic findings in painful adult scoliosis Spine 17(5):518–527

Fifty-five adults with painful scoliosis were evaluated with regard to diagnostic findings The curves were 49 % adult degenerative onset and 44 % idiopathic The older degenera-tive patients had myelographic defects most commonly within the primary curve and multiple abnormal, not necessarily painful, discs throughout the lumbar spine on discog-raphy The idiopathic group had myelographic defects most commonly in a compensa-tory lumbar or lumbosacral curve On discography, all idiopathic patients had at least one abnormal, painful disc, and 88 % had their pain reproduced Pain-producing pathology was frequently identified in areas that would not have been included in the fusion area according to accepted rules for treatment of idiopathic scoliosis

Key Articles

Swank S, Lonstein JE, Moe JH, Winter RB, Bradford DS ( 1981) Surgical treatment of

adult scoliosis A review of two hundred and twenty-two cases J Bone Joint Surg Am

63:268–87

Classical case series which predominantly deals with secondary degenerative scoliosis

Ponseti IV ( 1968) The pathogenesis of adult scoliosis In: Zorab PA (ed) Proceedings of

Second Symposium on Scoliosis Causation E & S Livingstone, Edinburgh

A comprehensive treatise on the pathogenesis of adult scoliosis by one of the pioneers of

scoliosis surgery

References

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2 Aebi M (1988) Correction of degenerative scoliosis of the lumbar spine A preliminary

report Clin Orthop Related Res 232:80 – 86

3 Albert TJ, Purtill J, Mesa J, McIntosh T, Balderston RA (1995) Study design: Health outcome

assessment before and after adult deformity surgery A prospective study Spine 20:

2002 – 2004; discussion p 2005

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7 Boachie-Adjei O, Gupta MC (1999) Adult scoliosis + deformity AAOS Instructional Course

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8 Bradford DS, Tay BK, Hu SS (1999) Adult scoliosis: surgical indications, operative

manage-ment, complications and outcome Spine 24:2617 – 2629

9 Bridwell KH (1996) Where to stop the fusion distally in adult scoliosis: L4, L5, or the

sacrum? AAOS Instructional Course Lectures 45:101 – 107

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LG (2003) Thoracolumbar deformity arthrodesis to L5 in adults: The fate of the L5–S1 disc

Spine 28(18):2122 – 2131

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positive sagittal balance in adult spinal deformity Spine 30(18):2024 – 2029

14 Grubb SA, Lipscomb HJ, Coonrad RW (1988) Degenerative adult onset scoliosis Spine 13:

241 – 245

15 Grubb SA, Lipscomb HJ (1992) Diagnostic findings in painful adult scoliosis Spine 17(5):

518 – 527

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scolio-sis Spine 19:1619 – 1627

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de l’Adulte Expansion Scientifique Fran¸caise, Paris, pp 199 – 222

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19 Johnson JR, Holt RT (1988) Combined use of anterior and posterior surgery for adult

scolio-sis Orthop Clin North Am 19:361 – 370

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147:238 – 252

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idio-pathic scoliosis: How it organizes curve patterns as a template to perform selective fusions

of the spine Spine 28(20S):S199–S207

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scolio-sis Spine 17:S304 – 309

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Course Lectures 41:251 – 255

Degenerative Scoliosis Chapter 26 731

24 Ponseti IV (1968) The pathogenesis of adult scoliosis In: Zorab PA (eds) Proceedings of sec-ond symposium on scoliosis causation E & Livingstone, Edinburgh

25 Reindl R, Steffen T, Cohen L, Aebi M (2003) Elective lumbar spinal decompression in the elderly: is it a high-risk operation? Can J Surg 46(1):43 – 46

26 Rinella A, Bridwell K, Kim Y, Rudzki J, Edwards C, Roh M, Lenke L, Berra A (2004) Late com-plications of adult idiopathic scoliosis primary fusions to L4 and above: The effect of age and distal fusion level Spine 29(3):318 – 325

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30 Swank S, Lonstein JE, Moe JH, Winter RB, Bradford DS (1981) Surgical treatment of adult scoliosis A review of two hundred and twenty-two cases J Bone Joint Surg 63A:268 – 287

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Spondylolisthesis Clayton N Kraft, Rüdiger Krauspe

Core Messages

distinct causes

lumbosacral junction and spondylolysis is a

result of a stress fracture

causes clinical symptoms

of choice for a first assessment

defect not visible on the lateral view

imaging modality of choice

pars defects not visible on standard

radio-graphs

the disorder, degree of slippage, intensity of

pain, and neurologic symptoms

spondylolis-thesis can be treated non-operatively

achieve stability, prevent progression and decompress neurologic structures

situ, instrumentation and posterolateral fusion with or without interbody fusion) depends on the surgeon’s familiarity with the approach as well as on the deformity

the primary aim of surgery but may be neces-sary to decompress foraminal stenosis

reduction of high-grade spondylolisthesis

high-grade spondylolisthesis because of a tether-ing effect

needed when a slipped vertebra is reduced and/or distracted

surgery are non-union and postoperative nerve root compromise

Epidemiology

There is a gender and ethnic factor to spondylolysis and spondylolisthesis

Spondylolysis is not the only cause of spondylolisthesis, only the most intensively

studied one Lumbar spondylolysis occurs in the general population at the rate of

around 5 % [36, 49] Based on data published by Fredrickson et al [24], the rate

of spondylolysis is less than 4.4 % for children under the age of 6 years and

approximately 6 % for adults According to Grobler and Wiltse [27], Caucasian

males are significantly more frequently affected than black females, indicating

that there is a gender as well as an ethnic factor underlying the condition This

presumption is underlined by a recent study by Whitesides et al [115], who were

able to demonstrate that in different ethnic groups there is a genetically

deter-mined difference in the upper sacral tilt, which again is associated with the

hyperextension and rotation

of the spine may cause pars defects

Numerous studies have shown that young athletes engaged in strenuous

train-ing in sports that incorporate intensive hyperextension and rotation of the

lum-bar spine have a predisposition to spondylolysis and subsequent

spondylolis-Spinal Deformities and Malformations Section 733