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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6030_Библиотеки_им_академика_М_И_Перельмана.pdf
AB
C
Figure 22–6
A 36-year-old man with structural hyperkyphosis, reduced with the innovative posterior technique. (A) Preoperative standing lateral radiograph. (B) Standing lateral
radiograph 40 months after surgery. A compression system from T1 to L1, consisting of two 4.8-mm threaded rods and 24 laminar hooks, achieved correction by closing 12
intersegmental gaps resulting from wide osteotomies. Note the narrowing of posterior disc spaces. An improvement to optimal physiologic ranges has been obtained
without any anterior surgery, and maintained at long-term follow-up. In an incorrect but widespread way of assessment, it corresponds to a 61% gain. (C) Standing antero-
posterior radiograph showing the fully segmental construct. Two cranial hooks are partially out of the picture.
A, B, C
Figure 22–7
A 42-year-old woman with severe thoracic kyphosis, operated on with the innovative posterior technique. A progression of 10 degrees had occurred during the 8 years prior
to surgery. (A) Preoperative standing lateral radiograph, showing marked wedging and structural changes in the apical region. (B) Standing lateral radiograph, 31 months
after surgery. The 4.8-mm rod/hook compression construct with 24 laminar hooks, obtained the closure of 12 intersegmental osteotomies. The implant system, with corrective forces acting directly on every single motion segment, achieved a harmonious correction to optimal physiologic ranges, which is maintained at follow-up. A strong
posterior fusion mass can be seen. (C) Standing anteroposterior radiograph showing the fully segmental construct, extending from T1 to L1.
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Figure 22–8
A 56-year-old woman with thoracic hyperkyphosis from postmenopausal osteoporosis. A rapid progression to a severity interfering with function had occurred
during the years prior to surgery, causing pain that was unresponsive to conservative measures. Correction and stabilization was obtained with the innovative
posterior technique, followed by a second-stage augmentation fusion after 4
months. (A) Preoperative standing lateral radiograph, showing a high thoracic kyphosis of great magnitude. (B) Standing lateral radiograph, 36 months after
surgery. The rod/hook compression construct consists of 22 laminar hooks and
two 3.2-mm threaded rods (the 4.8-mm rods had not yet been produced at that
time). Severity, rigidity, and osteoporotic bone did not prevent a stable correction
A
B
to optimal physiologic ranges, with a 63% gain. The restoration of a normal sagittal profile and balance coincided with a nearly complete relief of pain.
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22 POSTERIOR COLUMN SHORTENING FOR SCHEUERMANN’S KYPHOSIS
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ABC
Figure 22–9
(Courtesy of Juergen Harms, Germany.) Scheuermann’s kyphosis in a 16-year-old boy, operated on with the innovative posterior technique, without any anterior surgery.
An alternative instrumentation, consisting of segmentally placed transpedicular screws instead of laminar hooks, was utilized. (A) Preoperative standing lateral radio-
graph. (B) Postoperative standing lateral radiograph. The Moss-Miami compression construct consists of two 4-mm threaded rods and 30 pedicle screws, acting on 14
levels of intersegmental resection. Five-millimeter rods have been used by Harms in all more recent cases. (C) Standing anteroposterior radiograph showing the fully
segmental compression implant, extending from T1 to L3.
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SECTION II THE THORACIC SPINE
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3. Osteotomies: Resections of spinous processes, wide facetectomies, and
partial laminectomies of both the inferior and superior laminar borders
are performed at every intersegmental level of the entire fusion area,
obtaining gaps of 4 to 6 mm (Figs. 22–1 and 22–2). An angled, doubleaction rongeur and/or a Kerrison is used. A generous resection of the
facet joints, as far as the pedicles, is an essential step of this technique.
All bony contacts are largely interrupted. The ligamentum flavum is
entirely removed at all levels. The gaps extend uniformly over the entire width of the posterior spine (Figs. 22–2, 22–3, and 22–4). Any bony
spikes could act as hinges during the phase of closure of gaps and alter
the mechanics of correction.
A hypermobility in extension has thus been established at every
segment over the entire curve and will be utilized for the correction.
Decortication of areas later covered by rods can now be performed.
1. Instrumentation: The construct consists of two rods (threaded or
smooth), 24 to 26 closed laminar hooks with blades of 5-mm width and
two transverse connectors (Fig. 22–5). Constructs using 4.8- or 5-mmdiameter semirigid rods proved to have the best mechanical properties
for this technique, that is, sufficient intraoperative adaptability and
adequate postoperative strength. Moreover, corrections to optimal
physiologic ranges significantly increase the stiffness of the construct
and decrease the strain on the apex of the rods.
2. Insertion of instrumentation: The downward supralaminar hook immediately above the apex is the first one to be inserted (Fig. 22–4). The
first rod is then passed through the hook and advanced cranially
through the whole series of closed supralaminar hooks, until reaching
T1. There is no need for prebending if semirigid rods are used.
Threaded rods require nuts with each hook. Below the apex the upward infralaminar hooks are preloaded on the rod and inserted together as a unit. The apical vertebra is the only one that is left uninstrumented (Figs. 22–4 through 22–7). This does not alter the principle of
fully segmental fixation or change the absolute control of intersegmental correction at apical levels.
A minimal compression force is now applied, just enough to keep the
hooks in place. Any corrective tightening would narrow the gaps and make
the placement of hooks for the second rod difficult. The same sequence is
then repeated with the second rod.
1. Correction: Compressive forces, convergent to the apex, are now ap-
plied on both rods, beginning with the two opposing hooks facing the
apex, and continuing sequentially to the cranial and caudal ends
(Fig. 22–5C). These maneuvers are repeated alternately on both sides
and several times, always beginning at the apex. As compression
proceeds, the rods will gradually straighten out and the intersegmental
gaps (12 to 14) will close. At thoracic levels the opposite laminar
borders from partial resections will usually come into contact. Creating small notches for the hook blades will prevent their interference
with a complete closure of the gaps. Lumbar lordosis, initiating at the
T12-L1 interspace, is obtained by appropriate tightening of the hooks
on L1 and on L2. An intraoperative radiograph is taken to assess the
magnitude of correction and, most important, its distribution. This is
done to determine the segmental levels requiring adjustments. Finetuning is made easy by a complete and direct control of every single
motion segment. An absolutely harmonious distribution of intersegmental correction is an essential and distinctive step of this technique. It greatly influences the final result, and the incidence of instrument-related complications. Two transverse connectors can now be secured. With threaded rods the hooks are crimped to the rods for increased stability and for making any potential loosening of the nuts insignificant. This is done after a wake-up test.
2. Fusion: An iliac bone graft is harvested through a separate incision.
Decortication is then completed and morselized iliac bone added.
Alternative Instrumentations
Other types of instrumentation can be used, provided that the essential
principles of the technique (see above) are applied. Pedicle screws at all
levels instead of hooks have been successfully used in recent years, obtaining equally good results (Fig. 22–9).
Technical Points and Pitfalls
Correction is obtained exclusively by axial compression forces. There is no
cantilever action in this technique that could push the hooks into the
canal. All the hooks are constantly pulled away from the spinal cord, due
to the elasticity of semirigid rods and to constant compression and axial
loading (Fig. 22–5C). The use of hooks with narrow 5-mm blades prevents
the potential overlapping of blades inside the canal at the upper thoracic
levels and in small patients. Unnoticed overcorrection of a segment of the
curve (apical or other), or of the entire kyphosis, that is a correction to
values below physiologic ranges (15 degrees or less) is a possible pitfall
with this technique, even in rigid and severe deformities. It is due to the extremely favorable moment arm for posterior corrective forces and to their
fully segmental distribution. Awareness of this pitfall, and reliance on
final, postcorrection intraoperative radiographs, will help avoid this mistake.
Complications
Cranial or caudal junctional kyphosis is prevented:
1. By an appropriate extent of fusion/instrumentation levels (see above).
2. By avoiding excessive stress concentrations on the more mobile ends
of the curve (typical of corrections by cantilever action).
3. By a fully segmental distribution of load (unfeasible with constructs
using multilevel fixations).
4. By uniformly distributing the correction over the entire curve.
5. By starting off lumbar lordosis correctly.
6. By preserving the ligamentous structures between instrumented endvertebrae and adjacent motion segments.
Neurologic
Surgical correction of kyphosis, by whichever type of technique, carries an
increased risk of early or delayed neurologic complications from spinal
cord ischemia. Intraoperative monitoring (somatosensory and motor
evoked potentials, a postcorrection wake-up test) is used for early detection. An intensive postoperative watch for delayed neurologic symptoms
(at least 72 hours) is an absolute necessity. Great attention should also be
given to prevent a drop in postoperative blood pressure. A preoperative
MRI screening should become routine in all cases.
Postoperative Care
1. Patients start sitting and walking on the first postoperative day.
2. No need for external support.
3. Physical activities are restricted for 6 months.
4. Radiographic assessment of fusion at 6 months; gradual return to full
activities thereafter.
5. Osteopenic spines and overweight or noncompliant patients may require a plastic brace until fusion is solid.
Suggested Reading
Ponte A, Siccardi GL. Scheuermann’s kyphosis: posterior shortening pro-
cedure by segmental closing wedge resections. J Pediatr Orthop
1995;15:404.
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22 POSTERIOR COLUMN SHORTENING FOR SCHEUERMANN’S KYPHOSIS
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23
Anterior Release and Posterior Instrumentation and Fusion for Scheuermann’s Kyphosis
Thomas G. Lowe
Goals of Treatment
1. To balance and provide correction and stabilization of kyphosis of the
spine, and maintain maximum flexibility.
2. Final correction of thoracic kyphosis should be between 40 and 60
degrees.
3. Lumbar lordosis should be 20 to 30 degrees greater than thoracic kyphosis.
4. The sagittal plumb line should include the bodies of T1, T12, and the
sacral promontory.
Diagnosis
The diagnosis is based on clinical examination and radiographic criteria.
Clinical examination is based on the presence of a sharp, structural kyphosis of the thoracic or thoracolumbar spine, which is most visible in the for-
ward-bending position (Adam’s test). It is frequently associated with a flexible kyphosis of the cervicothoracic junction and a hyperlordosis of the
lumbar spine. Tight hamstrings are also commonly found.
Radiographic criteria of Scheuermann’s disease are based on the criteria of Sorenson, which include wedging of greater than 5 degrees of three
contiguous vertebrae. Commonly associated findings include disc narrowing, end-plate irregularity, and Schmorl’s nodes. Radiographs should include standing 36-inch posteroanterior (PA) and lateral as well as a hyperextension lateral utilizing a bolster over the apex of the kyphotic deformity.
Indications for Surgery
1. Skeletally mature patients with recalcitrant thoracic or thoracolumbar
back pain, severe cosmetic deformity, and occasionally pulmonary
compromise.
2. The above indications would generally include patients with thoracic
kyphosis (T1-T12) greater than 80 degrees or patients with thoracolumbar kyphosis (T10-L2) greater than 50 degrees.
Contraindications
1. Patients with severe osteopenia where adequate fixation may not be
achievable
2. Patients with abnormal PFTs who may not tolerate a thoracotomy
Advantages
1. It allows for preservation of segmental vessels, which contribute to the
blood supply of the spinal cord.
2. Includes the use of anterior structural support (structural graft or
cages) at the thoracolumbar junction, which helps to preserve normal
sagittal profile and to prevent pseudarthrosis and rod breakage postoperatively.
3. Provides for rigid internal fixation, which under normal circum-
stances eliminates the need for bracing.
Disadvantages
1. The need for a combined anterior-posterior approach as opposed to a
posterior alone approach, which has a higher failure rate. The use of a
thoracoscopic anterior release and fusion may offer some advantages
in the future, but at the present time this requires a longer operative
time and does not shorten the hospital stay.
2. Increased risk of complications associated with need for a thoracotomy
(incisional pain, atelectasis, pneumothorax, or pneumonitis).
Procedure
Anterior Release and Fusion
The thoracotomy is usually performed on the right side (to avoid the vena
cava) at the uppermost level of the release and fusion. This part of the procedure may be eliminated in skeletally immature individuals where remaining anterior growth will often fill in anterior column deficiencies according to Wolf’s law, similarly to what is seen with brace treatment.
Selection of anterior fusion levels: Anterior fusion levels should include all “fixed” levels on the hyperextension lateral radiograph along
with all thoracolumbar levels extending to the distal end of the anticipated
posterior instrumentation and fusion levels.
Use of structural grafts or cages: Structural support should be used at all
levels below T10 to preserve the sagittal profile of the spine and help prevent rod breakage and pseudarthrosis. All other levels should be packed
with morselized rib graft.
Use of single lung ventilation: The procedure is greatly facilitated by
the use of a double-lumen endotracheal tube, which allows collapse of the
ipsilateral lung for better exposure.
Segmental vessels: Segmental vessels may either be sacrificed or
spared. If sacrificed, they should be ligated over the midportion of the
vertebral body. Electrocautery should never be used to control bleeding
near the foramina because of the possibility of compromising the blood
supply to the spinal cord. If the vessels are to be spared, which is my preference, they should be mobilized and isolated with vessel loops. Small
malleable brain retractors fit nicely between the isolated segmentals, allowing easy access to the intervertebral discs (Fig. 23–1A).
Disc space preparation: It is usually not necessary to remove the rib
heads unless the kyphosis is extremely rigid. End plates should be exposed
back to the posterior annulus and decorticated down to bleeding bone except under the cages or structural grafts where cortical bone should be left
intact to provide support. Morselized autograft should be tightly packed
throughout the disc spaces above T10 and around the cages or structural
cages below T10 (Fig. 23–1B). A chest tube is always inserted prior to closure of the thoracotomy.
Posterior Instrumentation and Fusion
Instrumentation levels: Levels to be instrumented are based on the Cobb
method of measurement. Levels to be included within the instrumentation
are the upper Cobb level proximally and one level distal to the lower Cobb
level distally, that is, the first lordotic level. If there is an associated scoliosis that requires surgical treatment and extends beyond the kyphotic deformity, it will determine the length of the construct either distally or proximally rather than the kyphosis.
Approach: A midline posterior incision is made the length of the anticipated posterior fusion/instrumentation. The paraspinous musculature is
stripped subperiosteally to the tips of the transverse processes and held
laterally with cerebellar and Adson-Beckman retractors.
Insertion of instrumentation: First, pedicle screws are inserted at the
two distal levels of the anticipated posterior instrumented fusion. Next,
hook purchase sites are created. Above the apex of the kyphosis two
double-level pediculotransverse claws are used bilaterally. The upper
hook of each claw is a lumbar laminar hook placed around the transverse
process, and the lower hook of the claw is a pedicle hook directed upward
gripping the pedicle. Just below the apex, an additional pedicle hook is inserted on each side.
Next, the rod is pre-bent to the projected sagittal profile of the segments
to be instrumented based on the hyperextension lateral radiograph. The
rod is then inserted into the uppermost hook of the construct and is then
sequentially delivered into the hooks above the apex of the deformity and
the hook plugs are loosely inserted (Fig. 23–2A-C). Next, compression is
applied to each claw, and the set screws (plugs) are tightened. The rod is
then delivered into the pedicle screw below the apex and finally the
pedicle screws distally. Segmental compression is then applied toward the
apex of the deformity and final tightening of the hook and screw plugs.
This completes the corrective maneuvers of the construct. Finally, infralaminar hooks are added at the same level as the distal screw for protection of the screws against pullout. This construct thus provides four anchors above the apex of the kyphosis on each side and four anchors below
the apex on each side (Fig. 23–2C). Transverse connectors are applied near
the proximal and distal ends of the construct for additional security of the
construct (Fig. 23–2D).
Fusion: A separate small incision is usually made for the iliac bone
graft. Morselized autograft is then placed over the entire fusion area after
decortication and facet excision.
Avoiding Pitfalls and Instrument-Related Complications
1. Proximal junction kyphosis may result if the instrumentation is
stopped short of the upper Cobb level or if the kyphosis is overcorrected, that is, to less than 40 degrees.
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SECTION II THE THORACIC SPINE
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Segmental vessels
intact with vessel
loops
Partially
collapsed lung
Malleable
scoop
7
8
9
10
Rongeur
removing bony
end plate
11
12
L1
A
Morselized graft
packed into
disc space
7
8
9
T10
Lung partially
collapsed
Harms cages at
disc spaces T10 - L1
11
12
L1
B
Figure 23–1
(A) Exposure of spine through a transthoracic retroperitoneal approach. The ipsilateral lung has been collapsed using a double-lumen endotracheal tube to facilitate the
exposure. Segmental vessels have been preserved and mobilized with vessels loops. Discectomies are performed with Cobb elevators, rongeurs, and curets, and utilize
malleable retractors between the pleura and discs. The bony end plates are removed at levels above T10 and left in place below T10. (B) Morselized rib graft is packed
tightly into all disc spaces above T9. At the T9–10 disc spaces and below, titanium mesh cages are filled with graft and impacted into the posterior half of the disc space.
The end plates of the anterior half of the interspaces are then decorticated and autograft is packed into the anterior half of the disc spaces.
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23 ANTERIOR RELEASE FOR SCHEUERMANN’S KYPHOSIS
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Figure 23–2
(A) The anterior cages in place. (B) Two double-level pedicle transverse process hooks in a claw configuration are inserted bilaterally above the apex of the kyphosis. Just
below the apex a pedicle hook is placed on each side, and at the three lowest levels pedicle screws are inserted bilaterally. The rods are contoured to the anticipated residual kyphosis to be achieved. The rod on each side is inserted into the hooks; above the apex the hook plugs are inserted and compression is applied to each claw. The
distal ends of the rods are cantilevered to the hooks just below the apex and finally the distal screws. The screw plugs are partially tightened, and compression is applied
toward the apex of the kyphosis and plugs are tightened completely. (C,D) The completed construct consisting of interbody cages below T9 and double rods with hooks pro-
ximally and screws distally. Transverse connectors proximally and distally complete the construct.
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SECTION II THE THORACIC SPINE
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2. Distal junctional kyphosis can occur if the instrumentation is stopped
short of the first lordotic level, that is, one level distal to the lower
Cobb level or if structural support is not provided at the distal end of
the construct.
3. If cages or structural grafts are not used anteriorly below T10, “load
transfer” to the posterior instrumentation may result in rod failure and
pseudarthrosis distally as well as distal junctional kyphosis.
Non−Instrument-Related Complications
1. Respiratory complications (atelectasis, pneumothorax, and pneumoni-
tis) related to the thoracotomy
2. Neurologic complications related to cord ischemia: somatosensory
evoked potential (SSEP) and multimodality evoked potential (MEP)
monitoring and a “wake-up” test should all be used to provide early
assessment of possible neurologic problems.
Postoperative Care
1. Patient sitting and standing 24 hours postoperative
2. Incentive spirometer q3–4 hours while awake for 6 weeks
3. Chest tube out when output 쏝 50 cc q12h
4. No use of nonsteroidal antiinflammatory drugs (NSAIDs) for 8 weeks
5. No postoperative orthosis (unless osteopenia or compromised fixa-
tion)
6. Walking program for first 6 weeks
7. Back and aerobic exercise program begins 6 to 12 weeks
8. Gradual return to full activities
9. Erect PA and lateral radiographs at 6 weeks, 3 months, 6 months, and 1
year
Suggested Readings
Cobb JR. Outline for the study of scoliosis. In: Edwards JW, ed. In-
structional Course Lectures. Vol. 5. Ann Arbor, MI: American
Academy of Orthopaedic Surgeons; 1948:261–275.
Lowe T. Biomechanics of kyphosis correction. In: Haher T, Merola A, eds.
State of the Art Reviews: Spinal Biomechanics II. Philadelphia: Hanley
& Belfus; 1996:530–540.
Lowe T. Scheuermann’s disease. In: Bridwell K, DeWald R, eds. Textbook
of Spinal Surgery. Philadelphia: Lippincott-Raven; 1997:1173–1198.
Lowe T, Kasten M. An analysis of sagittal curves and balance following
Cotrel-Dubousset instrumentation for Scheuermann’s disease. Spine
1994;19:1680–1689.
Sorenson KH. Scheuermann’s Juvenile Kyphosis: Clinical Appearances,
Radiography, Etiology, and Prognosis. Copenhagen: Munksgaard;
1964.
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24
A New Classification System of Adolescent Idiopathic Scoliosis
Lawrence G. Lenke
Goals of Surgical Treatment
1. To be comprehensive with all types of adolescent idiopathic scoliosis
(AIS) curves classified
2. To be two dimensional with applicability to three-dimensional assessment
3. To be treatment based
4. To separate out specific curve types by objective radiographic criteria
5. To be highly reliable
6. To be logical, easily understood, and useful to scoliosis surgeons
Curve Classification Triad
1. Curve type
2. Lumbar spine modifier
3. Sagittal thoracic modifier
Each of these three components should be identified separately, and
then combined together to create the complete classification. Classification begins by reviewing the long cassette upright posteroanterior (PA)and
lateral radiographs as well as right- and left-side bending radiographs. The
spinal columns are divided into three regions: proximal thoracic (PT),
main thoracic (MT), and thoracolumbar/lumbar (TL/L). One must also
keep in mind the regional apices of curve designation with a main thoracic
apex being located between the body of T2 inclusive to the T11-T12 disc;
thoracolumbar curves having apices from the body of T12 to the body of L1
including the T12-L1 disc; and lumbar curves having apices extending
from the L1-L2 disc to the body of L4 inclusive.
Curve Types 1 to 6
Regional curves are separated into major (largest Cobb) and minor curves.
Specific objective criteria in the coronal and sagittal planes determine
whether the minor curves are structural or nonstructural.
Structural criteria in the coronal plane include inflexibility on side
bending 욷 25 degrees; in the sagittal plane, proximal thoracic (T2-T5) and
thoracolumbar (T10-L2) kyphosis 욷 +20 degrees (Table 24–1). Thus, each
region of the spine—the PT, MT, and TL/L—is designated as either struc-
tural or nonstructural based on these criteria.
The largest Cobb measurement is considered the major curve and thus
is always structural in these operative cases. A template can thus be
created whereby six curve types are designated: type 1—main thoracic;
type 2—double thoracic; type 3—double major; type 4—triple major; type
5—thoracolumbar/lumbar; and type 6—thoracolumbar/lumbar—main
thoracic (Table 24–2). For curve types 5 and 6, the thoracolumbar/lumbar
component should always be a larger Cobb measurement.
These curve type designations are treatment-based, for by and large the
regions of the spine that are designated structural will require instrumentation and fusion, whereas those nonstructural regions will not. Thus, although not directly providing fusion levels, the curve type designation
does implicate appropriate regions of the spine to be included in the instrumentation and fusion, and those regions that should be left unfused
(Table 24–3).
Lumbar Spine Modifier
The lumbar spine is a mobile region of the spine and serves as the foundation of the spine and pelvis. The degree of lumbar deformity is an important determinant of spinal balance and success with scoliosis instrumentation and fusion. Therefore, we have included a lumbar spine modifier to
classify the severity of the lumbar deformity in each scoliosis curve and to
complement the specific curve types 1 to 6.
Lumbar spine modifiers, A, B, and C, are based on the relationship of
the center sacral vertical line (CSVL) to the lumbar spine on long cassette
upright radiographs. For the lumbar spine modifier A, the CSVL lies between the lumbar pedicles up to the stable vertebra. The curve must have a
thoracic apex (curve type 1–4), which excludes any thoracolumbar or lum-
bar curves (types 5 and 6) (Fig. 24–1).
For lumbar modifier B, a major thoracic curve also exists, but the CSVL
falls on the apex of the lumbar spine between the medial border of the lum-
bar concave pedicle and the concave lateral margin of the apical vertebral
body or bodies (if the apex is a disc) because of the lateral deviation from
the midline of the lumbar spine (Fig. 24–2).
Table 24−1. Radiographic Surgical Structural Criteria
Coronal
(Side Bend)
(Degrees)
Proximal thoracic (PT) 욷 25 T2-T5 욷 +20
Main thoracic (MT) 욷 25 T10-L2 욷 +20
Thoracolumbar/lumbar
(TL/L)
Table 24−2. Curve Types 1 to 6
Type PT MT TL/L Curve Type
1 NS S (M) NS Main thoracic (MT)
2 S S (M) NS Double thoracic (DT)
3 NS S (M) S Double major (DM)
4 S S (M) S Triple major (TM)
5 NS NS S (M) Thoracolumbar/lumbar (TL/L)
6 NS S S (M*) Thoracolumbar/lumbar main
Surgical structural criteria:
PT, Proximal thoracic
MT, Main thoracic
TL/L, Thoracolumbar/lumbar
S, Surgical structural
NS, Surgical nonstructural
M, Major (largest curve)
M*, TL/L curve 욷 MT by 10 degrees
Table 27−3. Treatment Options as Designated by Curve Type
Curve Type
1-MT MT MT PSF or ASF
2-DT PT, MT PT, MT PSF or ASF
3-DM MT, TL/L MT-TL/L PSF
4-TM PT, MT, TL/L PT, MT, TL/L PSF
5-TL/L TL/L TL/L ASF or PSF
6-TL/L-MT TL/L, MT TL/L, MT PSF
ASF, anterior spinal fusion.
PSF, posterior spinal fusion.
And for the lumbar modifier C, the CSVL falls completely medial to the
concave lateral aspect of the thoracolumbar/lumbar apical vertebral body
or bodies (if the apex is a disc). Thus, lumbar modifier C may exist with any
of the curve types 1 to 6, with curve types 5 and 6 always having lumbar
curve modifier C because of the necessary deviation from the midline of
the apex of the major thoracolumbar/lumbar curve for the curve type 5 and
6 designation in operative cases (Fig. 24–3).
욷 25 T10-L2 욷 +20 쏜 I Nash-Moe
Structural
Regions
Sagittal
(Upright)
(Degrees)
Thoracic (TL/L-MT)
PT: Side bending Cobb 욷 25 degrees
T2-T5 kyphosis 욷 +20 degrees
MT: Side bending Cobb 욷 25 degrees
T10-L2 kyphosis 욷 +20 degrees
TL/L: Side bending Cobb 욷 25 degrees
T10-L2 kyphosis 욷 +20 degrees
Side bending residual apical
Nash-Moe rotation 쏜 1
Regions to be
Arthrodesed Approach
Axial
(Side Bend)
Sagittal Thoracic Modifier (−, N, +)
Thoracic sagittal alignment is crucial in the formation of scoliosis, the preoperative assessment of surgical indications, the specific operative approach, and instrumentation techniques utilized to correct the scoliosis.
Currently, instrumentation techniques are often principally guided by the
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SECTION II THE THORACIC SPINE
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A B
Figure 24–1
(A,B) Lumbar modifier A is depicted, in which the center sacral vertical line
(CSVL) lies between the pedicles up to the stable vertebra. Thus, no or minimal
scoliosis or rotation of the lumbar spine is present.
A B
Figure 24–2
(A,B) Lumbar modifier B position is depicted, in which the CSVL touches the apical vertebral body (bodies) or pedicle. Thus, minimal to moderate lumbar spine
deviation from the midline and rotation is present.
Apical
body
Apical
disc
A B
Eurostile
Figure 24–3
(A,B) Lumbar modifier C is depicted, in which the CSVL lies medial and does not
touch the apical vertebral body or the bodies immediately above and below the
apical disc. Thus, the lumbar spine demonstrates marked deviation from the midline and rotation.
24 ADOLESCENT IDIOPATHIC SCOLIOSIS
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