Klippel-Feil syndrome (KFS) is a rare disorder involving the abnormal fusion of two or more cervical vertebrae. The severity of KFS can vary significantly among affected individuals.
Understanding Klippel-Feil Syndrome
This congenital condition involves fusion of two or more cervical vertebrae in the neck. This fusion occurs during early fetal development, specifically between the third and eighth weeks of gestation, when the cervical somites fail to segment properly. While historically considered extremely rare, with an estimated incidence of about 1 in 40,000 to 42,000 live births, more recent research suggests a higher prevalence in asymptomatic individuals, possibly ranging from 1 in 172 to 1 in 83. Females are reported to be affected slightly more often than males.
The condition was first described in 1912 by Maurice Klippel and André Feil. They observed patients with a short, webbed neck, limited neck movement, and a low hairline at the back of the head. Not all individuals with KFS exhibit these classic features, and the syndrome can present with a wide range of other abnormalities throughout the body. The extent of vertebral fusion can vary, impacting the specific symptoms and their severity.
How Klippel-Feil Syndrome Develops
Genetic factors play a role in the development of KFS, with identified mutations in specific genes. For instance, mutations in the GDF6, GDF3, and MEOX1 genes have been linked to the condition. The proteins produced by the GDF6 and GDF3 genes are involved in the formation of bones and joints, including those in the spine, while the MEOX1 gene regulates the separation of vertebrae during early development. While some cases are inherited in an autosomal dominant pattern (one copy of the altered gene is sufficient) or an autosomal recessive pattern (both copies of the gene must have mutations), many cases occur sporadically without a clear family history.
Common Symptoms and Related Health Issues
The symptoms associated with Klippel-Feil syndrome can vary widely in severity and presentation. The classic triad of symptoms includes a short neck, a low hairline at the back of the head, and restricted neck movement. However, fewer than 50% of individuals with KFS display all three of these features. The specific symptoms depend on the location and extent of the vertebral fusion.
Beyond the classic triad, KFS is frequently associated with abnormalities in other body systems. Orthopedic issues are common, such as scoliosis, which is an abnormal side-to-side curvature of the spine, often involving the thoracic and lumbar regions. Sprengel’s deformity, a condition where one shoulder blade is positioned higher than the other, can also occur in about 30% of cases. Individuals may also experience chronic headaches and neck muscle pain due to the altered spinal mechanics.
Additional associated health issues can include:
Congenital heart defects, such as ventricular septal defects, affecting approximately 15% to 30% of individuals.
Kidney problems, including aplasia (absence of a kidney) or horseshoe kidney, observed in up to 33% of cases.
Hearing loss, sometimes part of Wildervanck syndrome, reported in about 30% of individuals.
Neurological issues, such as nerve damage, spinal stenosis (narrowing of the spinal canal), or even mirror movements (involuntary mimicking of one hand’s movement by the other), which can develop due to spinal cord compression or abnormalities.
Other potential anomalies including spina bifida, rib anomalies, cleft palate, and facial asymmetry.
Diagnosis and Treatment Approaches
Diagnosing Klippel-Feil syndrome typically involves a thorough evaluation, beginning with a detailed medical history and physical examination. During the physical exam, a doctor will assess the head, neck, shoulders, and spine for any apparent abnormalities, including the range of neck motion. Imaging techniques are then employed to confirm the diagnosis and assess the extent of vertebral fusion and any associated anomalies.
Plain X-rays of the cervical spine, including anteroposterior, lateral, and flexion-extension views, are typically the initial imaging studies to identify fused vertebrae and evaluate spinal stability. Computed tomography (CT) scans provide more detailed images of the bony structures, which is particularly useful for visualizing the specific patterns of fusion and detecting conditions like canal stenosis. Magnetic resonance imaging (MRI) is often used to assess soft tissues, identify any spinal cord compression or nerve damage, and detect associated neurological conditions such as Chiari malformation. If at least two cervical vertebrae are fused and other signs indicate a congenital origin, KFS is diagnosed. Genetic testing may also be considered in some cases.
Treatment for Klippel-Feil syndrome is primarily symptomatic and supportive, focusing on managing specific issues and preventing complications. Non-surgical interventions often include physical therapy to improve neck mobility, strengthen surrounding muscles, and manage pain. Pain management may involve over-the-counter medications like NSAIDs or, for more severe pain, prescription medications. Activity modification, such as avoiding contact sports or activities that stress the cervical spine, is also often recommended, especially for individuals with higher cervical fusions.
In some situations, surgical interventions become necessary. Surgery is typically performed to stabilize the cervical spine, correct spinal deformities like scoliosis, or relieve pressure on nerves or the spinal cord. Procedures might include cervical fusion to stabilize unstable segments or decompression surgeries to alleviate nerve compression. Given the varied presentation and potential for multiple associated conditions, a multidisciplinary approach involving various medical specialists, such as orthopedic surgeons, neurologists, and physical therapists, is beneficial for comprehensive care. Regular, long-term monitoring is important to address any new symptoms or complications that may arise.