Neurological Deficits in Congenital Kyphosis

INTRODUCTION:
Neurological deficits are a known complication of congenital kyphosis. The role of the type of anomaly is documented, but the role of canal diameter is not documented.

PURPOSE:
To investigate the relationship between the anomaly and canal size in congenital kyphosis and the occurrence of neurological deficits.

METHODS:
A retrospective chart and radiographic review was performed on all cases of congenital kyphosis seen. The canal diameter narrowing was expressed as the percent of the adjacent normal level, where a is the antero posterior (AP) size of the canal at the level above the apex of the kyphosis and b is the AP size of the canal at the apex of the kyphosis.

RESULTS:
Twelve of the 61 cases had neurological loss due to the kyphosis, ranging from reflex changes to paraparesis. The Type 1 kyphosis was divided into three subcategories - complete vertebral agenesis; a rudimentary vertebra (hypogenesis) and a wedged vertebra (hypoplasia).

The average stenosis increased sharply if the kyphosis was >50°, with kyphosis of 60° being accompanied by canal narrowing of 50%. In addition the number of cases of neurological loss increased if the kyphosis was >60°.

SUMMARY:
The occurrence of neurological loss in congenital kyphosis is related to the type of anomaly, the degree of kyphosis and the canal stenosis at the apex of the deformity.