Klippel-Feil Syndrome describes congenital fusion of at least two of the seven vertebrae in the cervical-spine. In addition there may be fusion or anomalies of vertebrae in the thoracic or lumbar-spine.
Estimated frequency of occurrence varies widely from 1 in 100 to 1 in 42,000 births, females about 65% of the cases. Many people actually have the syndrome but are never diagnosed because their symptoms may be so minor.
The defect occurs around the 5th to 8th week of gestation. The exact cause is unknown at this time, but there does appear to be a mix of both inherited and sporadic cases. Genetic testing is being done at this time to isolate the gene which may be responsible for causing KFS.
Shortness of the neck, reduced cervical range-of-motion, and a low posterior hairline are the most common features of the syndrome. Sudden neurologic injury or death after minor trauma is possible in persons with certain high-risk patterns of cervical fusion and spinal motion.
Depending on the extent and levels of fusion, a small percentage of persons will develop cervical or craniocervical instability due to the larger relative load placed on the normal unfused sections of the cervical-spine. In the event of instability, these sections may need to be surgically fused to prevent serious injury. Surgery is also useful to relieve constriction of the spinal cord in persons with stenosis (narrowing) of the spinal canal.
If Scoliosis is present it will often need to be surgically corrected, as progressive Ccoliosis of the thoracic spine may lead to very serious breathing difficulties.
In addition a large percentage of persons will develop osteoarthritis due to hypermobility of the unfused vertebrae adjacent to a fused segment. Various Non-Steroidal-Anti-Inflammatory-Drugs may be used to lessen the associated pain.
Physical therapy may be useful in reducing the involuntary mirror movements of the hands in patients with synkinesis.
Minimally involved persons can lead a normal life with the exception that activities that could injure the neck should be avoided. Many severely involved patients enjoy a good prognosis if early and appropriate treatment is instituted when needed. For the more detailed information on which this summary was based.