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Abstract

Transient kyphotic deformity arises in most infants with achondroplasia. In a minority, a fixed and angular kyphosis develops, which can cause serious neurologic sequelae later in life. We assessed a protocol for preventing development of such fixed kyphosis in a sequential, unselected series of 66 infants with achondroplasia. This study demonstrates the efficacy of early prohibition of unsupported sitting and, in those in whom such prohibition proves insufficient, use of bracing. When the proposed algorithm was followed, none of the infants had development of a progressive kyphotic deformity. On this basis, it appears that the secondary risks of angular kyphosis, previously estimated to be between 10 and 15% in individuals with achondroplasia, can be completely eliminated.

Achondroplasia: a comprehensive clinical review

“…This results in paradoxical movement with inspiration, which is often misinterpreted as being retractions reflecting respiratory distress. Thoracolumbar kyphosis. Virtually all infants develop a dynamic thoracolumbar kyphosis in infancy [64], but this is not present at birth. Lumbar hyperlordosis. Exaggerated lordosis (“swayback”) arises when walking begins. Limited elbow extension.…”

Optimal management of complications associated with achondroplasia

“…Flexible kyphotic curves have been reported in over 90% of infants with achondroplasia, although the majority of these curves spontaneously improve once ambulation commences. Progression to a fixed kyphotic deformity occurs in 15%–30% of adults 19,34,35. Progressive disruption of the vertebral epiphyseal ring that begins during childhood, combined with decreased growth in the anterior vertebral sections can create a progressive thoracolumbar kyphosis in adolescents, which is further exacerbated by age-related degenerative changes in the facet joints during adulthood 36.…”

“…This curve is then thought to contribute to adult onset spinal stenosis 19,36,37. The kyphosis is thought to be exacerbated by early sitting where the effects of trunk hypotonia, increased head weight, and increased ligamentous laxity combine with the effect of gravity to force the child into a slumped sitting position, which can contribute to permanent spinal damage by increasing the anterior wedging of the vertebra and subsequent narrowing of the spinal canal 4,25,27,35,36,38,39. This knowledge has led to the recommendation that sitting be restricted until the infant with achondroplasia is able to independently achieve this transition.…”

“…This knowledge has led to the recommendation that sitting be restricted until the infant with achondroplasia is able to independently achieve this transition. Furthermore, parents of infants with achondroplasia should avoid pieces of equipment that reinforce this characteristic kyphosis such as baby slings or umbrella strollers 35. When a kyphotic deformity is identified after commencement of independent ambulation, management may include education about positioning for nonfixed deformities, bracing,18,39,40 and/or operative correction, usually for progressive curves or anterior vertebral wedging associated with a fixed angular kyphosis 36,41.…”

“…When a kyphotic deformity is identified after commencement of independent ambulation, management may include education about positioning for nonfixed deformities, bracing,18,39,40 and/or operative correction, usually for progressive curves or anterior vertebral wedging associated with a fixed angular kyphosis 36,41. Pauli et al35 developed an algorithm for the monitoring and treatment of kyphosis in children, which they proposed could eliminate the neurological risks of angular kyphosis. However, the management of spinal kyphosis in achondroplasia is not consistent and requires further investigation to determine the optimal type and timing of management strategies.…”