Klippel-Feil syndrome presents with an abnormal fusion of 2 or more bones in the cervical spine. This creates a characteristic appearance of a short neck with resulting facial asymmetry, low hairline, and limited neck mobility. This can lead to chronic headaches, limited range of neck motion, and neck muscle pain. More importantly, it can also result in spinal stenosis, neurologic deficit, cervical spinal deformity, instability, and spinal stenosis. Patients can be poly-syndromic in their presentation as well.
Etiology is unknown. It can co-present with fetal alcohol syndrome, Goldenhar syndrome, as well as Sprengel’s deformity.
Mutations in the GDF6, GDF 3, and MEOX1 genes can cause Klippel-Feil syndrome. GDF6 is involved in proper bone formation while GDF3 is involved in bone development. MEOX1 gene creates the homeobox protein MOX1 that regulates the separation of vertebrae. GDF6 and GDF3 abnormalities are inherited in an autosomal dominant pattern while MEOX1 mutations are autosomal recessive.
It was initially reported in 1912 by Maurice Klippel and Andre Feil. Klippel-Feil syndrome occurs in approximately 1 in 40,000 to 42,000 newborns worldwide with a slight preference to females. Nouri et al. illustrated 2.0% incidence of Klippel-Feil syndrome on MRI in a global cohort of 458 patients. Brown et al. reviewed 1400 skeletons and put the incidence at 0.71%. It is important to recognize that pediatric unsymptomatic patients, that never undergo cervical imaging and who do not present with obvious physical deformity, are likely to graduate into adulthood unaware of their condition.
Faulty segmentation occurs during embryo development 3 to 8 week of gestation. This is a failure of normal segmentation or formation of the cervical somites.
A thorough and complete history and physical should be entertained. This should include all major systems as well as a detailed family genetic history. It is also important to recognize that patients with Klippel-Feil syndrome may be predisposed to congenital spinal stenosis. As such, a relatively low impact or low energy injury may induce a significant neurologic deficit.
Physical exam findings include a shortened neck stature and low-lying hairline. Neurologic symptoms may include radiculopathy and myelopathy. Formal assessment for related sequence should also be entertained. A strict neurologic exam including cranial nerves, sensory, motor, and rectal tone (for acute neurologic changes) is mandatory.
The classic complete clinical triad of the low hairline, short neck, and restricted neck motion is only present 50% of patients with Klippel-Fiel.
Physical examination should be complete and detailed. The presentation may occur simultaneously with Sprengel’s deformity, Duane syndrome, renal agenesis, Wildervanck syndrome, and other vascular and cardiac abnormalities. Approximately 50% of patients with Klippel-Feil will present with concurrent scoliosis. Fifty percent may have atlantoaxial instability. Approximately 30% will present renal disease and 30% with deafness. All systems need to properly detailed and examined.
Laboratory tests may be done as appropriate. The concern should be given to the possible presence of cardiac, gastrointestinal (GI), and urinary disorders.
Radiographic evaluation of the cervical spine in patients with Klippel-Feil includes plain radiographs, CT, and MRI.
Overall, treatment is conservative and symptom driven.
Those with a 1 or 2 level fusions below C3 are monitored and treated conservatively. They may play contact sports such as hockey and rugby.
Patients who are high risk due to spinal deformity can undergo activity modification. Those with a fusion above C3, especially to the occiput, should avoid contact sports and are more likely to be symptomatic. This also true for those patients with long fusions of the cervical spine.
Importance should also be placed on the poly-syndromic presentation of patients. Pediatricians can link a variety of specialists into the care cycle for cardiac, renal, or gastrointestinal congenital abnormalities. This interdisciplinary care becomes even more vital if patients are considered to be operative candidates.
Patients with persistent neurological pain, myelopathy, new onset muscle group weakness, and documented spinal instability can be considered operative candidates.
Surgical decision making is driven by both spinal deformities as well as instability. Cervical fusion can occur from either anterior or posterior approaches secondary to evaluation.
Anterior approach can include anterior cervical fusion or corpectomy with the placement of either synthetic or bone graft. Cervical total disc arthroplasty is being investigated as a surgical option. This modality has shown some positive benefit regarding the quality of life outcomes and prevention of adjacent level disease in the degenerative adult population. Posterior approaches can also be used including decompression and fusion through a variety of instrumentation procedure options. In certain cases of severe deformity, a combined anterior-posterior approach can also be used.
Surgical or bracing intervention may be indicated for associated compensatory thoracic scoliosis.
Those with fusion above C3 tend to be more symptomatic.
By definition, Klippel-Feil is a heterogeneous presentation. Prognosis can be related to the Samartzis classification system.
Samartzis et al. noted that over an eight-year period approximately two-thirds of patients with Klippel-Feil syndrome had no symptoms. Those with a type-I deformity had more axial symptoms while those with type II and type III were the patients who developed myelopathy and radiculopathy.
Patients can present with obvious physical abnormalities, but nearly 50% of the patients will not present with the typical physical exam findings and features. Great care must be taken in the advising of patients with high cervical fusions. X-ray is a very reasonable and moderately safe modality to trend patient deformity.