The stabilizing effects of different orthoses in the intact and unstable upper cervical spine: A cadaver study

Background: Although cervical orthoses are frequently used in prehospital s tabilization and in the definitive treatment for lesions of the cervical sp ine, there is little information about the control of extension-flexion, la teral bending, and rotation given to individual segments by different desig ns. Methods: In an experimental in vitro study with four fresh frozen cadavers, the halo vest was compared with the soft collar, prefabricated Minerva bra ce, and Miami J collar, The controlling effects for the segments C1-2 and C 2-3 were tested for all four devices in the intact and the unstable spine w ith an Anderson type II fracture of the odontoid. Results: All four orthoses reduced the range of motion at both C1-2 and C2- 3 of the intact spine significantly, although none of the three semirigid d el ices provided a halo-like immobilization in the intact spine. The osteot omy of the odontoid increased the range of motion in the segment C1-2, The soft collar did not give any clinically relevant stability to the unstable spine. Miami J and Minerva brace provided a similar moderate control in the sagittal plane but a much better control of "torque" in the upper cervical spine. The halo vest did not allow any measurable motion in any plane with our experimental external loading. Conclusion: The halo vest seems to be the first choice for conservative tre atment of unstable injuries of the upper cervical spine, although pin track problems, accurate fitting of the vest, and a lack of patient compliance l ead to clinical failures.