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Case Study Discussion
K.S. is a 3–year, 10–month–old
girl with multiple congenital anomalies of her thoracolumbar
spine. She was first evaluated at age 1 year, 3 months when her
left shoulder was noted to be lower than the right. Her birth
history was notable only in that she was born by Cesarean section
due to extended labor. There is no family history of spinal congenital
anomalies. At the initial evaluation, radiographs revealed a
mid–thoracic right hemivertebra with probable fusion of
ribs on the left side in the same region, creating a 21°
right thoracic curve. A second hemivertebra on the left at the
thoracolumbar junction and a third hemivertebra between L3 and
L4 were also noted. Initial management consisted of observation
with interval radiographic studies. At 2 years, 5 months of age,
her right shoulder was 2 cm higher than the left and radiographs
demonstrated a 38° right thoracic curve. At age 3 years,
8 months the right upper thoracic curve had increased to 43°
(Fig 1).
To better delineate the complex
anatomy of her congenital anomalies, a CT scan of the thoracolumbar
spine with 3–D reconstruction was obtained (Fig 2a, b).
This demonstrated a hemivertebra at approximately the T7 level,
and another hemivertebra at the T11 level. A third unincarcerated
hemivertebra was noted at the T12–L1 junction on the left
(opposite side from hemivertebra noted above) (Fig 3). Congenital
fusion of ribs at the T6 through T8 level on the left was clearly
identified. Also, an isolated hemivertebra was noted at the L3
level. Management options include:
1. Continued observation.
2. Application of a thoracolumbar spinal orthosis.
3. In–situ fusion of the levels of progressive deformity
to prevent curve progression.
4. Hemi–epiphysiodesis of the convexity of the deforming
regions both anteriorly and posteriorly, to stabilize the curve
and perhaps achieve partial correction with growth.
Progressive Congenital Spinal
Deformity: Discussion
Keith H. Bridwell, MD
Washington University School of Medicine St. Louis, MO
The authors have documented progression
from a 21° curve to a 43° curve. The pathology of the
congenital curve with an apex at T7 appears to be the following:
On the left side there is an unsegmented bar with three ribs
fused together. On the right side there appears to be a large
congenital block. At the top of that block is a hemivertebra
which appears to be fused into two segments below. This block
is taller on the right side than the left.
The most malignant combination
of congenital deformities is that of an unsegmented bar on the
concave side and unincarcerated hemivertebra on the convex side.3,5
Because the hemivertebra seems to be fused into the two segments
below in this case, we are not dealing with such a malignant
combination. No sagittal x–rays have been provided. If the
spine is in kyphosis, this suggests that the hemivertebra is
the principal deforming force. If the spine is in lordosis, this
usually suggests that the unsegmented bar is the principal deforming
force.
There are three hemivertebra
below the area of principal deformity. Two are at the thoracolumbar
junction and the third one is in the mid–lumbar spine. Two
of those hemivertebrae are incarcerated and the left hemivertebra
at T12/L1 is unincarcerated. The hemivertebra at T12/L1 probably
has the greatest potential for progression in the future. But
to date, the three hemivertebrae below seem to balance each other
out. Continued observation is therefore appropriate for them.
Clearly for the major deformity
centered on T7, continued observation and application of orthosis
will not be helpful. The spine is growing faster on the right
side than the left, and the deformity is starting to wedge the
growth plates just above and below.
There appear to be open disc
spaces and, therefore, open growth plates at the few segments
above and below the principal congenital deformity. The best
treatment would be a hemi–epiphysiodesis of the convexity,
both anteriorly and posteriorly. By including one or two segments
below and two or three segments above the area of principle deformity,
we will hopefully slow down the convexity and allow the concavity
to catch up. The main potential for "catch–up"
will be the included fusion segments immediately above and below
the congenital block. The greatest potential for correction with
growth exists if the procedure is performed in a patient under
the age of five years.1,4
Hopefully, with this approach,
we would not see too much "adding on" to the deformity.
With a posterior fusion alone, we would not have any hope of
seeing correction of the deformity and it would be more likely
that we would see "adding on" from continued wedging
of the segments above and below. With an unsegmented bar on one
side and essentially a block vertebra on the other side, the
potential for crankshaft should not be as great as in cases that
are purely caused by failure of formation. However, in recently
reviewing our patients2 who experienced crankshaft phenomenon,
we did find that there was a significant incidence of crankshaft
in congenitals with the same combination that this patient has.
In conclusion, based on the available
information, I would recommend a convex anterior and posterior
hemi–epiphysiodesis. T6 to T8 should be included, and I
would probably include three or four segments above and one segment
below that block.
References
1. Andrew T, Piggott H. Growth arrest for progressive scoliosis.
Combined anterior and posterior fusion of the convexity. J Bone
Joint Surg. 1985;67B(2):193–197.
2. Hamill CL, Bridwell KH, Lenke,
LG, et al. Posterior arthrodesis in the skeletally immature patient:
Assessing the risk for crankshaft. Is an open triradiate cartilage
the answer? Abstract submitted March 1995 to the Scoliosis Research
Society.
3. McMaster MJ, Ohtsuka K. The
natural history of congenital scoliosis. A study of two hundred
and fifty–one patients. J Bone Joint Surg. 1982;64A(8):1128–1147.
4. Winter RB, Lonstein JE, Denis
F, Sta–Ana de la Rosa H. Convex growth arrest for progressive
congenital scoliosis due to hemivertebrae. J Pediatr Orthop.
1988;8:633–638.
5. Winter RB, Moe JH. The results
of spinal arthrodesis for congenital spinal deformity in patients
younger than five years old. J Bone Joint Surg. 1982;64A(3):419–432.
Progressive Congenital Spinal
Deformity: Discussion
Maurice Bergoin, MD
Department of Pediatric Orthopaedics
CHU Nord, Marseille, France
This complex congenital spine
deformity must be divided into three problems.
I. The Upper Right Thoracic
Curve
In this area we observe one hemivertebra on T7 on the right side,
as well as rib fusion on the left side from T6 through T8 and
from T3 to T5. This deformity looks like a unilateral unsegmented
bar with a controlateral hemivertebra as described by Nasca in
1975. The unsegmented vertebrae are suspected on the 3–D
reconstruction.
The natural history of the deformity
usually indicates a progression of 8š to 10š each year.
In this case the progression between 1 year, 3 months and 3 years,
8 months is 22°. Waiting with continued observation is contraindicated
because this deformity is one of the more progressive.
Rib resections and osteotomies
of the bar itself are hazardous and are not able to induce growth
on the concave side. The safer solution is to reduce the growth
on the convex side by a hemi–epiphysiodesis of the convexity,
including four vertebrae above and three vertebrae under the
T7 right hemivertebra. The hemi–epiphysiodesis should be
performed by anterior and posterior approaches (in one or two
stages). A short–compression instrumentation on the convex
side during the posterior approach should be considered.
A post–operative cast is
necessary for six months. We recommend a partial wearing of a
Milwaukee™ brace.
II. The Thoracolumbar Area
There are two alternate hemivertebrae: one on T11 on the right
side and one between T12 and L1 on the left side. At present
the two hemivertebrae appear balanced but this will not continue.
The hemivertebra on T11 is semi–segmented
and the progression on this level is usually very small. The
hemivertebra between T12 and L1 is fully segmented in this area
(thoraco&endash;lumbar junction). The progression is usually
important.
When hemiepiphysiodesis is obtained
on the upper thoracic level (one year later) it will be necessary
by a simultaneous approach to fuse in situ the left thoracolumbar
hemivertebra anteriorly and posteriorly. The lower rib can be
resected and used as a bone graft. This must be followed by cast
immobilization for six months.
The left thoracolumbar hemivertebra
is surgically altered to an unsegmented hemivertebra, to induce
a balanced growth with the right T11 hemivertebra. No surgery
is required on the T11 hemivertebra.
III. Hemivertebra Between
L3 and L4 on Left Side
On the x–ray we are not
able to determine if it is a semi–segmented or a full–segmented
hemivertebra. Currently there is no deformity and no need for
early surgery. Observation is appropriate, and perhaps in the
future a hemivertebral in situ fusion will be required.
Conclusion
All management options are valuable on different levels:
Hemiepiphysiodesis on the right
upper thoracic curve;
In situ fusion on left thoracolumbar hemivertebra;
Spinal orthosis (Milwaukee brace™) after surgery during
the growth; and
Continued observation of the lumbar left hemivertebra.
References
1. Bergoin M, Bollini G. Spinal surgery before age 5 years. Editorial
Round Table. J Pediatr Orthop. 1993(pt B):1:93–94.
2. Bergoin M, Bollini G, Gennari
JM, One stage hemivertebral excision and arthrodesis on congenital
oblique take off in children aged less than five years. J Pediatr
Orthop. 1993(pt B);1:108–112.
3. Bollini G, Bergoin M, and
Coll., Hemivertebrae excision and fusion in children aged less
than five years. J Pediatr Orthop. 1993(pt B);1:95–101
4. Dubousset J, Katti E, Serine
R. Epiphyseodesis of the spine in young children for congenital
spinal deformations. J Pediatr Orthop. 1993(pt B);1:292;123–130.
5. McMaster M, and Ohtsuka K.
The natural history of congenital scoliosis. J Bone and Joint
Surg. 1982;64A:1128–1147.
6. Nasca RJ, Stelling FH, Steek
HH. Progression of congenital scoliosis due to hemivertebrae
and hemivertebrae with bars. J Bone and Joint Surg. 1975;57A:45–46.
7. Winter RB, Moe, JH. The results
of spinal arthrodesis for congenital spinal deformity in patient
younger than five years old. J Bone and Joint Surg. 1982;64A:419–432.
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