• Monchai Ruangchainikom, Michael D Daubs, Akinobu Suzuki, Tetsuo Hayashi, Gil Weintraub, Christopher J Lee, Hirokazu Inoue, Haijun Tian, Bayan Aghdasi, Trevor P Scott, Kevin H Phan, Areesak Chotivichit, and Jeffrey C Wang.
• *Department of Orthopaedic Surgery, University of California Los Angeles, Santa Monica, CA; and †Department of Orthopaedic Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand. Dr. Wang is now with the Department of Orthopaedic and Neurological Surgery, University of Southern California, Los Angeles, CA.
• Spine. 2014 May 20; 39 (12): 932-8.

Study DesignRetrospective analysis of kinematic magnetic resonance images.ObjectiveTo provide baseline data on the segmental angular and translational motion of the degenerated cervical spine by subtype of kyphotic cervical deformity and to elucidate the relationship between motion and degree of spinal cord compression.Summary Of Background DataKyphotic deformities of the cervical spine are relatively common and are classified as either global or focal. Nevertheless, the effects of kyphotic subtype on cervical segmental motion and degree of spinal cord compression are unknown.MethodsA total of 1171 symptomatic patients (618 females, 553 males) underwent cervical kinematic magnetic resonance imaging in the neutral, flexion, and extension positions. Cervical spines demonstrating kyphosis were included and classified into 3 groups: (1) "global kyphotic deformity" (C-type) (n = 54); (2) "sigmoid deformity" (S-type) with kyphotic upper and lordotic lower cervical segments (n = 29); and (3) "reverse sigmoid deformity" (R-type) with lordotic upper and kyphotic lower cervical segments (n = 39). Translational motion, angular motion, and degree of spinal cord compression were evaluated for each cervical level along with the changes associated with flexion and extension.ResultsIn the C- and R-types, angular motion with extension was increased in the upper cervical spine, where there was kyphosis; when compared with the S-type, in which there was lordosis in the upper segments. The results were opposite for flexion angular motion. R-type displayed more translational motion at C3-C4 and C5-C6. Degree of static spinal cord compression of R-type was higher than the others at C3-C4. The dynamic spinal cord compression increased in extension more than flexion in all subtypes.ConclusionCervical spine studies that aim to investigate kyphotic deformities should make efforts to discern the different subtypes of kyphotic deformities to more accurately characterize and study the effects that the sagittal alignment has on the kinematics of the spine and the degree of spinal cord compression.

23 keywords...

hide…