IX./4.: Spondyloepiphyseal dysplasia

IX./4.: Spondyloepiphyseal dysplasia
This chapter will describe etiology and pathogenesis of
spondyloepiphyseal dysplasia, after reading this chapter the reader will
we be able to recognize this congenital deformity.
IX./4.1.: Definition
Spondyloepiphyseal dysplasia is the impairment of enchondral bone development
which primarily affects the vertebrae but may also be seen on the epiphysis of
long bones. Two types are known: congenital and late-onset (tarda).
IX./4.2.:Etiology, inheritance
Incidence is 1:100.000. The congenital type shows autosomal dominant
inheritance, while the late-onset appears to be X-chromosome linked recessive.
Because of this late-onset type affects boys, but it has also been found in girls
when inheritance proved to be autosomal dominant.
IX./4.3.: Etiology
The impairment of epiphyseal bone development is due to the abnormal synthesis
of type II collagen in the congenital form, due to the mutation of the COL2A1
gene on the 12th chromosome.
IX./4.4.: Clinical presentation, symptoms
Figure 1. Dwarfism
characterized by short limbs
and trunk is easy to
recognize in the early
post-natal period in the
congenital form. We
frequently see flat vertebral
bodies
Figure 2. The dens axis isn’t fused with the body of the axis, (os
odontoideum), which may lead to atlantoaxial instability, causing
neurological symptoms (myelopathy, hypotonia, increasing muscle
weakness, impairment of ventilation).
The late onset form manifests in childhood and is characterized by
disproportionate dwarfism : patients have a short trunk with relatively long limbs.
Both types are associated with platyspondylia (flat vertebral bodies), dysplasia of
the epiphysis of the femoral head, and early-onset degenerative joint diseases
especially in the hips, knees and shoulders. This leads to painful limitation of
range of motion. Pathological spinal curves are frequent (kyphosis, scoliosis),
coxa vara, acetabulum protrusion and genu valgum or varum.
IX./4.5.: Radiology
Figure 3. Flat vertebral bodies with
narrowing of the proximal side.
Figure 4. Dorsolumbar kyphosis is frequent.
Figure 5. Long bones appear to have irregular epiphyses.
IX./4.6.: Treatment
When treating patients suffering from spondyloepiphyseal dysplasia, the
following problems must be considered: Atlantoaxial instability which may be
solved by dorsal atlanto-occipital fusion. Deformity of the spine may be treated
with corsettes or dorsal spondylodesis, similar to the treatment protocol of
idiopathic scoliosis. Coxa vara should be treated by intertrochanteric valgus
osteotomy, Deformities around the knee should also be treated by correctional
osteotomies.
Figure 6. The implantation of a prosthesis is necessary in adult patients with severe osteoarthritis.