For details on Neurofibromatosis Type 1 (NF-1), I will refer
you to Wikipedia: https://en.wikipedia.org/wiki/Neurofibromatosis_type_I
As this blog focuses on spinal deformity in children and adolescents
following is a brief summary as it relates to the musculoskeletal system (spine
and extremities):
1. NF-1 causes tumors along nervous system which
can grow anywhere on the body.
2. Musculoskeletal abnormalities:
a. Spine: Meningocoeles, dural ectasia, scoliosis,
kyphosis
b. Skeletal muscle weakness
c. Long bones: pseudarthrosis (most commonly
tibia), limb hypertrophy
3. Approximately 20% of NF-1 patients will have
spinal deformity.
4. There are two types of spinal deformity in NF-1
a.
Idiopathic-like: looks and behaves more like
idiopathic scoliosis
b. Dystrophic
i. Sharp, angulated spine deformity (kyphosis, scoliosis and kyphoscoliosis)
ii. More common in the thoracic spine
iii. Spines can start out having a more idiopathic-like deformity, which can change into a dystrophic type.
iv. Causes penciling or thinning of the rib heads which can migrate into the spinal canal
9 year old female
5. Dural Ectasia: Circumferential enlargement or
ballooning of the thecal sac, nerve root sleeves and spinal canal.
a.
More common in lumbar spine
b.
Causes vertebral body scalloping
c.
Also thins the pedicles
6. Treatment
a.
For the idiopathic-like deformities, lower
magnitude deformities are amenable to bracing. Surgical treatment mirrors
guidelines for idiopathic scoliosis.
b.
For the dystrophic deformities:
i. Bracing
is limited in effectiveness
ii. Surgery
is performed for lower magnitude deformities due to the sharper-angulated
deformities, increasing difficulty in achieving necessary spinal fixation and
the risk of neurologic changes (such as weakness, sensory changes,
bowel/bladder dysfunction).
Next several blog posts actual surgical cases of NF-1 will be presented.