Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 74 docx

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
Theolderthepatient,thelessnecessitythereistocorrectthedeformity.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.
724 Section Spinal Deformities and Malformations
Cardinal Symptoms and Imbalance
Curve correction is indicated
inthepresenceofsignificant

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 osteotomy) 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 canbeachievedthroughmobilizationandosteotomiesofthe
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)maybe
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
ab
Figure 6. Smith-Peterson arch osteotomy
This technique creates lordosis and is usually applied to one or multiple levels. a The 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.

b These 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 posterior approach and using a unilateral cage or t ricortical bone graft
by either an anterior lumbar interbody fusion (ALIF)oraposteriorlumbarinter-
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
canstillbeaugmentedby,e.g.,granulartricalciumphosphate.
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
Debatecontinuesontheindicationsforalumbosacral 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
ordertopreventiliosacraljointdegenerationoranearlyhipproblem.Itisalso
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
726 Section Spinal Deformities and Malformations
a
b
cd
Figure 7. Pedicle reduction osteotomy
a The osteotomy is started by removing the posterior arch including the facet joints until only the pedicle stump at the
transition to the posterior wall ofthe vertebral body is left with also thetransverse process removed.
b The pedicle stump
is then excavated continuously into the vertebral body, which is emptied by means of an “eggshell” procedure.
c The
remaining posterior bridge between the two wholes of the pedicle stumps is then resected by a large Kerrison rongeur.
d The 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
caneitherbedonebyananterior(ALIF)oraposterior(PLIF)approach(
Case
Study 2
).
Degenerative Scoliosis Chapter 26 727
abcd
e

f
Case Study 1
A young female teacher presented with progressive idio-
pathic scoliosis. At the age of 35 years the curve measured
62° (
a).Threeyearslaterthecurvehadprogressedto75°(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 ( -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).
728 Section Spinal Deformities and Malformations
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 degenerationof 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)Theadultscoliosis.EurSpineJ14(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,orthe
sacrum? Instr Course Lect 45:101 – 7
This articles highlights the many aspects which must be weighed and discussed with the
patientbeforedecidingonalongfusiondowntothemiddleordistallumbarspine.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
Theauthorsreviewed21patientswith the diagnosisof degenerativescoliosis.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.
730 Section Spinal Deformities and Malformations
Key Articles
Swank S, Lonstein JE, Moe JH, Winter RB, Bradford DS (1981)Surgicaltreatmentof
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
1. Aebi M (2005) The adult scoliosis. Eur Spine J 14(10):925–948
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
4. Ali RM, Boachie-Adjei O, Rawlins BA (2003) Functional and radiographic outcomes after
surgery for adult scoliosis usingthird-generation instrumentation techniques. Spine 28(11):
1163–1169
5. Ascani E, Bartolozzi P, Logroscino CA, Marchetti PG, Ponte A, Savini R, Travaglini F, Binazzi
R, Di Silvestre M (1986) Natural history of untreated idiopathic scoliosis after skeletal matu-
rity. Spine 11(8):784–789
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7. Boachie-Adjei O, Gupta MC (1999) Adult scoliosis + deformity. AAOS Instructional Course

Lectures 48(39):377–391
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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
10. Deviren V, Berven S, Kleinstueck F, Antinnes J, Smith JA, Hu SS (2002) Predictors of flexibil-
ity and pain patterns in thoracolumbar and lumbar idiopathic scoliosis. Spine 27(21):
2346–2349
11. Deyo RA, Cherkin DC, Loeser JD, Bigos SJ, Ciol MA (1992) Morbidity and mortality in asso-
ciation with operations on the lumbar spine. The influence of age, diagnosis, and procedure.
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12. Edwards CC, Bridwell KH, Patel A, Rinella AS, Jung Kim Y, Berra A, Della Rocca GJ, Lenke
LG (2003) Thoracolumbar deformity arthrodesis to L5 in adults: The fate of the L5–S1 disc.
Spine 28(18):2122–2131
13. Glassman SD, Bridwell K, Dimar JR, Horton W, Berven S, Schwab F (2005) The impact of
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
16. Grubb SA, Lipscomb HJ, Suh PB (1994) Results of surgical treatment of painful adult scolio-
sis. Spine 19:1619–1627
17. Guillaumat M (1993) Les scolioses lombaires de l’adulte. In: SOFCOT, Chirurgie du Rachis
de l’Adulte. Expansion Scientifique Fran¸caise, Paris, pp 199–222
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pathic scoliosis: How it organizes curve patterns as a template to perform selective fusions
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22. Marchesi DG, Aebi M (1992)Pedicle fixation devices in the treatment of adult lumbar 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. RinellaA,BridwellK,KimY,RudzkiJ,EdwardsC,RohM,LenkeL,BerraA(2004)Latecom-
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ment of adults with idiopathic scoliosis. J Bone Joint Surg Am 69(5):667–675
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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Am 19:339–345
732 Section Spinal Deformities and Malformations
27

Spondylolisthesis
ClaytonN.Kraft,RüdigerKrauspe
Core Messages
✔
Spondylolisthesis is the end result of various
distinct causes
✔
Spondylolisthesis is a disorder of the entire
lumbosacral junction and spondylolysis is a
result of a stress fracture
✔
Not every radiographically evident slippage
causes clinical symptoms
✔
Standard radiographs are the imaging modality
of choice for a first assessment
✔
Oblique radiographs may demonstrate a pars
defect not visible on the lateral view
✔
In the presence of neurologic deficit, MRI is the
imaging modality of choice
✔
Multi-slice CT with image reformation detects
pars defects not visible on standard radio-
graphs
✔
Treatment rationale is based on the etiology of
the disorder, degree of slippage, intensity of
pain, and neurologic symptoms

✔
The vast majority of patients with spondylolis-
thesis can be treated non-operatively
✔
The primary aim of all surgical options is to
achieve stability, prevent progression and
decompress neurologic structures
✔
The surgical technique (posterolateral fusion in
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
✔
Reduction of low-grade spondylolisthesis is not
the primary aim of surgery but may be neces-
sary to decompress foraminal stenosis
✔
There is continuing debate on the subject of
reduction of high-grade spondylolisthesis
✔
The L5 nerve root is at high risk when reducing
high-grade spondylolisthesis because of a tether-
ing effect
✔
Anterior buttressing (interbody fusion) is
needed when a slipped vertebra is reduced
and/or distracted
✔
Frequent complications after spondylolisthesis

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
ofspondylolysisislessthan4.4%forchildrenundertheageof6yearsand
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
occurrence of pars defects.
Sports with intensive
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