Abstract:Klippel Feil Syndrome (KFS) is a congenital disorder characterized by failure of segmentation of cervical vertebrae, resulting in “fusions” at any level of the cervical spine. Clinical diagnosis of KFS occurs at a mean age of 7.1 years, with children diagnosed with KFS often exhibiting reduced motion and function characterized by reduction of upward and downward motions of the head on the neck (flexion/extension), axial rotation, and tilting of the head side to side (lateral bending). More importantly, however, previous KFS studies have acknowledged possible compromises to the structural integrity and overall health of the cervical spine in the presence of abnormal fusion. Instances of instabilities such as fracture and large amounts of mobility at vertebral segments adjacent to fusion have been recorded, both posing significant neurological and physiological dangers to an individual afflicted with KFS. While fusion and instability appear to be interrelated, more intrinsic evaluation of KFS-related instabilities is needed. Current KFS studies, relying predominantly on static radiographic modalities, have been unsuccessful in identifying factors contributing to craniocervical (CC) destabilization in the presence of congenital vertebral fusion. It has been hypothesized that fusion of vertebral bodies induces abnormal stress distributions that catalyze instances of fracture along any KFS spine segment. Using Finite Element (FE) Modeling and Analysis to characterize motion alterations and irregular stress patterns associated with vertebral fusion, a high fidelity computational representation of a KFS affected cervical spine segment spanning the base of the occiput to C6 was constructed. Computer Tomography (CT) images were used for vertebral reconstruction with soft tissue components such as intervertebral discs (IVDs), articular cartilages (ACs), and the transverse ligament were modeled as homogenous solid components.