Autosomal recessive inheritance, where both copies of a gene contain mutations, is especially associated with C5-C6 fusion. Another autosomal dominant form (mapped on locus 8q22.2), known as KFS with laryngeal malformation, has been identified. It is also known as segmentation syndrome 1. Diagnosis
The heterogeneity of KFS has made it difficult to outline the diagnosis as well as the prognosis for this disease. Classification
In 1912, Maurice Klippel and Andre Feil independently provided the first descriptions of KFS. They described patients who had a short, webbed neck; decreased range of motion (ROM) in the cervical spine; and a low hairline. Feil subsequently classified the syndrome into 3 categories:
Type I—Fusion of C2 and C3 with occipitalization of the atlas. In 1953, further complications were later reported by McRae; flexion and extension is concentrated within the C1 and C2 vertebrae. As with aging, the odontoid process can become hypermobile, narrowing the space where the spinal cord and brain stem travel (spinal stenosis). Type II—Long fusion below C2 with an abnormal occipital-cervical junction. Similar to the C2-C3 fusion of McRae and could be viewed as a more elaborate variation. Flexion, extension, and rotation are all concentrated in the area of an abnormal odontoid process or poorly developed ring of C1 which cannot withstand the effects of aging. Type III—A single open interspace between two fused segments. Cervical spine motion is concentrated at single open articulation. This hypermobility may lead to instability or degenerative osteoarthritis.
This pattern can be recognized as the cervical spine is often seen to be at an angle or hinge at this open segment.A classification scheme for KFS was proposed in 1919 by Andre Feil, which accounted for cervical, thoracic, and lumbar spine malformations.However, in 2006, Dino Samartzis and colleagues proposed three classification-types that specifically addressed the cervical spine anomalies and their associated cervical spine-related symptoms, with additional elaboration on various time-dependent factors regarding this syndrome. Treatment
Treatment for KFS is symptomatic and may include surgery to relieve cervical or craniocervical instability and constriction of the spinal cord, and to correct scoliosis.If symptomatic treatment fails, spinal surgery may provide relief. Adjacent segment disease and scoliosis are two examples of common symptoms associated with Klippel–Feil syndrome, and they may be treated surgically. The three categories treated for types of spinal cord deficiencies are massive fusion of the cervical spine (Type I), the fusion of 1 or 2 vertebrae (Type II), and the presence of thoracic and lumbar spine anomalies in association with type I or type II Klippel–Feil syndrome (Type III).Adjacent segment disease can be addressed by performing cervical disc arthroplasty using a device such as the Bryan cervical disc prosthesis. The option of the surgery is to maintain range of motion and attenuate the rate of adjacent segment disease advancement without fusion. Another type of arthroplasty that is becoming an alternate choice to spinal fusion is Total Disc Replacement. Total disc replacement objective is to reduce pain or eradicate it.