In 1912, Maurice Klippel and Andre Feil independently provided the first descriptions of Klippel-Feil syndrome in patients who manifested the following:
•Short, webbed neck
•Decreased range of motion (ROM) in the cervical spine
•Low hairline
Feil subsequently classified the syndrome into the following three types:
•Type I - Massive fusion of the cervical spine
•Type II - Fusion of one or two vertebrae
•Type III - Presence of thoracic and lumbar spine anomalies in association with type I or type II Klippel-Feil syndrome
Since the original description, other classification systems have been advocated to describe the anomalies, predict the potential problems, and guide treatment decisions.
In a series of articles, Samartzis et al suggested their own classification system, [1, 2] which stratified patients as follows:
•Type I - Single-level fusion
•Type II - Multiple, noncontiguous fused segments
•Type III - Multiple, contiguous fused segments
Gray et al described 462 patients with Klippel-Feil syndrome and found that the level of fusion did not greatly affect the incidence of neurologic symptoms. The most frequent level they identified was a defect of the occiput to C1, C2, and C3. These produced the most symptoms; lesions below C3 and 4 were slightly less likely to cause symptoms. Twenty-seven percent of symptoms occurred in the first decade.
Nagib et al described three types and related the incidence of neurologic symptoms to each type as follows:
•Type I - Two sets of block vertebrae with open intervening spaces that can sublux gradually or with acute trauma
•Type II - Craniocervical anomalies with occipitalization of the axis and basilar invagination; this causes increased mobility at the craniocervical level and can lead to foramen magnum encroachment; it can be associated with Arnold-Chiari malformation and syringomyelia
•Type III - Fusion of one or more levels with associated spinal stenosis
Patients with Klippel-Feil syndrome usually present with the disease during childhood, but they sometimes present later in life. The challenge to the clinician is to recognize the associated anomalies that can occur with Klippel-Feil syndrome and to perform the appropriate workup for diagnosis.