Klippel-Feil Syndrome

Pathogenesis and Association with Sprengel Deformity

Klippel-Feil syndrome rarely occurs in isolation. In most cases, it is combined with the most common congenital anomaly of the shoulder girdle — Sprengel deformity (Sprengel deformity), or congenital high scapula.

Normally, between the 6th and 8th weeks of gestation, the fetal scapula should descend from its initial mid-cervical position to its definitive mid-thoracic position. In this syndrome, this process is disrupted.

• The pathology occurs with equal frequency in both boys and girls.
• In unilateral cases, the anomaly more frequently affects the left scapula.
• Specialists suggest an autosomal dominant inheritance pattern for this combined defect.

Impact on the Spine and Scoliosis Development

Impaired development and segmentation of the spine in Klippel-Feil syndrome is a direct risk factor for the development of congenital scoliosis (congenital scoliosis) — a lateral curvature of the spinal column greater than 10 degrees.

Congenital scoliosis in this syndrome is often associated with other major vertebral structural anomalies:

• Formation of hemivertebrae (hemivertebrae).
• Block vertebrae (block vertebrae).
• Appearance of butterfly vertebrae (butterfly vertebrae).

In addition to Klippel-Feil syndrome, congenital scoliosis can be associated with other genetic defects, such as spondylocostal and spondylothoracic dysostoses, Goldenhar syndrome (Goldenhar), and VACTERL association. Spinal deformities can also be triggered by connective tissue disorders (Marfan and Ehlers-Danlos syndromes) or neurological pathology (cerebral palsy, tethered cord syndrome).

For reference: The risk of progression for any scoliotic deformity depends on the patient's sex (the prognosis is usually worse in girls), the initial severity of the curvature, and the child's growth potential, which is assessed radiographically using the Risser grade (Risser grade).

Diagnostic Imaging and Specific Signs

CT and MRI are the primary and most informative imaging modalities for visualizing deformities in Klippel-Feil syndrome. They allow for a detailed assessment of upper thoracic and cervical segmentation defects, as well as the exclusion of occult spinal cord pathologies (e.g., syringomyelia or tumors). Indications for advanced cross-sectional imaging when scoliosis is detected include left thoracic curvature, pain syndrome, or abnormal neurological symptoms.

For example, a frontal CT scan (bone window) clearly demonstrates the high position of the left scapula alongside segmentation defects.

Key Radiologic Findings:

1. High scapular position: it is rotated such that the inferior pole of the glenoid (glenoid) is directed toward the spine.
2. Shape alteration: the superomedial angle of the scapula protrudes and is positioned abnormally high, and the affected bone itself is larger than normal.
3. Omovertebral bone (omovertebral bone): a specific sign representing a osseous or fibrous connection between the superomedial angle of the scapula and the lamina (lamina) or spinous process of a vertebra.

Class and exam questions

What else to study on this topic

• Congenital and idiopathic scoliosis: classification, Cobb angle measurement, and assessment of growth potential using the Risser scale.
• Radial ray dysplasia and its association with genetic syndromes (VACTERL, Holt-Oram syndrome, Fanconi anemia).
• Neurocutaneous syndromes in pediatrics: skeletal, neurological, and thoracoabdominal manifestations of tuberous sclerosis.
• Juvenile idiopathic arthritis: definition, subtype classification, and systemic manifestations.
• Radiographic diagnosis of congenital foot deformities: assessment of varus, valgus, and equinus alignments.

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.