Successful Treatment of Atlantoaxial Subluxation in an Adolescent Patient with BrachytelephalangicChondrodysplasia Punctata

Abstract

Brachytelephalangic chondrodysplasia punctata (CDPX1) is characterized by brachytelephalangy and nasomaxillary hypoplasia, in addition to stippled epiphyses. Some reports have described infants with CDPX1 who exhibited cervical spinal stenosis. However, the natural course of cervical spinal lesions in this condition has not been elucidated. Here, we report a very rare adolescent case of CDPX1, which demonstrated progressive myelopathy caused by atlantoaxial subluxation and a subsequent retroodontoid pseudotumor, successfully treated with surgery. Our case highlights a new clinically important fact that upper cervical spinal lesions in CDPX1 can deteriorate even after childhood and thus need close monitoring.

Figure 1

(a, b) Lateral plain radiographs of the cervical spine in flexion and extension at the age of 5 years. Multiple dysplastic vertebral bodies and atlantoaxial instability with os odontoideum are evident (white arrows).

Figure 2

(a, b) Preoperative anterior-posterior and lateral plain radiographs of the cervical spine revealing multiple dysplastic vertebral bodies (white arrowheads). (c, d) Preoperative lateral plain radiographs of the cervical spine clearly demonstrating unstable atlantoaxial subluxation. (e) An anterior-posterior plain radiograph of the right hand revealing typical shortening of the distal phalanges (brachytelephalangy) of the thumb and middle and ring fingers. (f) Preoperative sagittal reconstructed computed tomography showing the segmented os odontoideum (white arrow). (g) Preoperative sagittal T2-weighted magnetic resonance (MR) images showing a severely compressed spinal cord at the C1/2 level with signs of myelomalacia inside the cord. A low-intensity retroodontoid mass is evident on the T2-weighted MR images. (h) Preoperative axial T2-weighted MR image at the C1/2 level revealing a severely compressed spinal cord. The white dotted lines in (g) indicate the level of (h).

Figure 3

(a, b) Lateral radiographs of the cervical spine in flexion and extension at 1 year after surgery demonstrating a stabilized O-C2 segment. (c) Sagittal reconstruction computed tomography taken at 1 year after surgery showing solid fusion between the grafted iliac bone and occipital bone (white arrow). (d) Sagittal T2-weighted magnetic resonance image taken at 1 year after surgery revealing a well-decompressed spinal cord with marked regression of the retroodontoid pseudotumor.