Infantile Kyphosis Secondary to Lumbar Hypoplasia: Six Cases with Excessive Upright Sleeping as a Possible Cause

Abstract

Abnormal thoracolumbar kyphosis in infants may be due to lumbar hypoplasia that resolves with development of upright posture. The cause of this deformity has not been previously identified. The goal of this study was to find whether excessive time in an upright posture while sleeping and sitting may play a role in the etiology of infantile thoracolumbar kyphosis. We retrospectively reviewed infants with the diagnosis of kyphosis from 2001 to 2005. Inclusion criteria were patients diagnosed prior to age 3 years without syndromic, neuromuscular, or congenital kyphosis and minimum 2-year follow-up. Serial radiographic evaluation was used to assess change in kyphotic deformity. Six infants with an average age of 7 months at the time of diagnosis were identified. All had marked thoracolumbar kyphosis with vertebral wedging and scalloping. Some had pseudosubluxation at the T12-L1 level. The initial average Cobb angle was 30° (normal, 0°-5°). Careful history revealed that all patients slept in an upright posture in addition to sitting while awake. All of the patients were observed following parental instruction in proper sleeping and sitting habits. At last follow-up, all patients had normal sagittal alignment with an average Cobb angle of 1.3°. Proper sleeping and sitting habits with good spine support is recommended for infantile thoracolumbar kyphosis with lumbar hypoplasia. Allowing "tummy time" during waking hours may help the paraspinal muscles gain strength to provide support to the spine. Radiographic evidence of vertebral body height restoration may be delayed for several years.