Definition
- Vertebral anomalies that causes sagittal plane growth asymmetry
Classification of congenital vertebral anomalies
- Usually located at the apex of the curve
- Winter et al.
- Type I - failure of formation
- Failure of vertebral body formation
- Hemivertebrae
- most commonly in the thoracolumbar transition area of T11–L2
- Wedge vertebrae
- Butterfly vertebrae
- More common
- More serious
- because they lead to a sharp angular kyphosis that may cause paraplegia.
- Type II - failure of segmentation
- Failure of vertebral segmentation
- Block vertebrae
- Bar (Unilateral longitudinal)
- The presentation is typically in childhood with worsening kyphosis and neurologic deficits such as neurogenic bladder, lower-extremity weakness, and paresthesias.
- Spinal fusion is the treatment of choice.
- Type III - mixed failure of formation and segmentation
(B) failure of segmentation (B1: Bar; B2: Vertebral block)
(C) mixed deformities.
Natural history
- Congenital kyphosis is encountered less often than scoliosis.
- Kyphosis may progress at 2– 7° per year.
- Most kyphotic anomalies are in the lower thoracic or thoracolumbar region.
- If left untreated, some patients with congenital kyphosis may become paraplegic
Treatment
- Conservative
- Bracing does not prevent deformity progression or provide long-term correction of a congenital kyphotic deformity.
- Nonsurgical management does not play a role in the treatment of congenital kyphosis.
- Congenital kyphosis does not respond to non-operative treatment.
- Surgery
- Preoperative evaluation
- Cardiopulmonary assessment
- Evaluation of the genitourinary system
- Detailed neurologic examination
- MRI of the neural axis
- CT scan to define osseous abnormalities
- Principles
- Halo gravity traction:
- Uses the viscoelastic biomechanical properties of the spine
- Pros
- A traction-induced decrease in deformity has been shown to reduce preoperative patient risk scores along with the complexity and duration of the subsequent surgery.
- Gradual correction allows the spinal cord and its blood supply to adjust to the increased length and shape of the spine → reducing the risk of neurological insult as in acute correction.
- Severe deformity may be complicated by respiratory dysfunction, and traction has also shown substantial benefit for improving preoperative respiratory function in these cases.
- Age and fusion
- Before 8 years old thoracic fusion can cause thoracic insufficiency syndrome
- After 8 years old thoracic fusion causes a cosmetic defect only (Thoracic short)
- Osteotomy
- When doing PVCR makes sure to remove one lamina above and below to prevent kinking of the cord
- If the spine is scoliotic it makes it easier to resected the vertebrae as the
- Vertebrae body is curved towards the convex side
- The large vessels will be pushed away
- Level of fusion:
- from stable vertebrae to stable vertebrae
- Stable on the sagittal plane when the Sacral (CSVL) line cuts the midpoint of the vertebral
- Approach
- Most cases can be done with a posterior approach only
- Decompression
- with fusion
- Posterior in situ fusion
- Indication
- A young child (1-5 years old) with a kyphosis < 50°.
- 360 fusion
- Indication
- Kyphosis > 50° + older children
- Indication for
- Symptomatic neural compression at the apex of the kyphosis
- Technique
- Posterior only
- Circumferential decompression
- may be achieved through a single-stage posterior surgical approach.
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