Indications
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Fixed sagittal deformity secondary to previous surgery with an anterior fusion mass, traumatic deformity, neoplastic disease, or congenital anomalies
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The need to introduce up to 35 degrees of lumbar lordosis, the need to introduce 10 cm of posterior trunk translation, or correction of a sharp angular kyphosis or flat back syndrome
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Symptoms including inability to maintain horizontal gaze, severe fatigue on standing and ambulation, intractable back pain, disfigurement, generalized decreased functional capacity, and radicular symptoms
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Failure of conservative nonsurgical treatment and documented progression of deformity
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Progression of deformity after a previous surgery either secondary to pseudarthrosis or adjacent to a previous fusion
Planning and positioning
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Standing 36-inch anteroposterior and lateral x-ray projections are obtained to assess global and regional alignment of the spine. For the lateral x-ray, the spinal deformity is most accurately represented with the knees and hips fully extended.
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Flexion and extension x-rays allow assessment of the flexibility of the deformity. The flexibility of the deformity plays a significant role in surgical planning.
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Anteroposterior images are obtained to evaluate scoliotic abnormalities.
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Magnetic resonance imaging (MRI) is performed to assess the full dimensions of the spinal canal and the degree of foraminal and central canal stenosis. This assessment is particularly important because manipulation of the spine into lordosis may significantly advance the level of stenosis leading compression of the neural elements. Under these circumstances, the surgeon may consider a decompression of the neural elements before correction of sagittal deformity.
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Patients should be examined for a hip flexion contracture, which may be the cause of sagittal plane malalignment. Using the Thomas test, patients may be evaluated for flexion contracture of the hip. The modified Thomas test can differentiate between tightness of the iliopsoas versus the rectus femoris.
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In patients with a sagittal deformity localized to the spine, it is imperative to localize the deformity to the cervical, thoracic, or lumbar spine. In patients whose deformity is localized to the cervical spine, as the patients lay in the supine position, their heads and upper thoracic spines remain elevated from the table.
Figure 76-1:
The patient is positioned prone on a spinal Jackson table.
Planning and positioning
- •
Standing 36-inch anteroposterior and lateral x-ray projections are obtained to assess global and regional alignment of the spine. For the lateral x-ray, the spinal deformity is most accurately represented with the knees and hips fully extended.
- •
Flexion and extension x-rays allow assessment of the flexibility of the deformity. The flexibility of the deformity plays a significant role in surgical planning.
- •
Anteroposterior images are obtained to evaluate scoliotic abnormalities.
- •
Magnetic resonance imaging (MRI) is performed to assess the full dimensions of the spinal canal and the degree of foraminal and central canal stenosis. This assessment is particularly important because manipulation of the spine into lordosis may significantly advance the level of stenosis leading compression of the neural elements. Under these circumstances, the surgeon may consider a decompression of the neural elements before correction of sagittal deformity.
- •
Patients should be examined for a hip flexion contracture, which may be the cause of sagittal plane malalignment. Using the Thomas test, patients may be evaluated for flexion contracture of the hip. The modified Thomas test can differentiate between tightness of the iliopsoas versus the rectus femoris.
- •
In patients with a sagittal deformity localized to the spine, it is imperative to localize the deformity to the cervical, thoracic, or lumbar spine. In patients whose deformity is localized to the cervical spine, as the patients lay in the supine position, their heads and upper thoracic spines remain elevated from the table.
