title: [The biomechanics of hyperextension injuries of the subaxial cervical spine].
abstract: Hyperextension injuries of the subaxial cervical spine are potentially hazardous due to relevant destabilization. Depending on the clinical condition, neurologic or vascular damage may occur. Therefore an exact knowledge of the factors leading to destabilization is essential. In a biomechanical investigation, 10 fresh human cadaver cervical spine specimens were tested in a spine simulator. The tested segments were C4 to 7. In the first step, physiologic motion was investigated. Afterwards, the three steps of injury were dissection of the anterior longitudinal ligament, removal of the intervertebral disc/posterior longitudinal ligament, and dissection of the interspinous ligaments/ligamentum flavum. After each step, the mobility was determined. Regarding flexion and extension, an increase in motion of 8.36 % after the first step, 90.45 % after the second step, and 121.67 % after the last step was observed. Testing of lateral bending showed an increase of mobility of 7.88 %/27.48 %/33.23 %; axial rotation increased by 2.87 %/31.16 %/45.80 %. Isolated dissection of the anterior longitudinal ligament led to minor destabilization, whereas the intervertebral disc has to be seen as a major stabilizer of the cervical spine. Few finite-element studies showed comparable results. If a transfer to clinical use is undertaken, an isolated rupture of the anterior longitudinal ligament can be treated without surgical stabilization.
authors.affiliation: Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Köln, Kerpener Str. 62, 50937, Köln, Deutschland. gregor.stein@uk-koeln.de.
authors.forename: G
authors.initials: G
authors.lastname: Stein
authors.affiliation: Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Köln, Kerpener Str. 62, 50937, Köln, Deutschland.
authors.forename: C
authors.initials: C
authors.lastname: Meyer
authors.affiliation: Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Köln, Kerpener Str. 62, 50937, Köln, Deutschland.
authors.forename: L
authors.initials: L
authors.lastname: Ingenhoff
authors.affiliation: Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Köln, Kerpener Str. 62, 50937, Köln, Deutschland.
authors.forename: J
authors.initials: J
authors.lastname: Bredow
authors.affiliation: Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Köln, Kerpener Str. 62, 50937, Köln, Deutschland.
authors.forename: L P
authors.initials: LP
authors.lastname: Müller
authors.affiliation: Klinik und Poliklinik für Orthopädie und Unfallchirurgie, Universitätsklinikum Köln, Kerpener Str. 62, 50937, Köln, Deutschland.
authors.forename: P
authors.initials: P
authors.lastname: Eysel
authors.affiliation: Abteilung Unfallchirurgie, Handchirurgie und Orthopädie, Vinzenz-Palotti-Hospital, Bergisch-Gladbach, Deutschland.
authors.forename: G
authors.initials: G
authors.lastname: Schiffer
mesh_terms: D001696:Biomechanical Phenomena / Q000502:physiology*; D002574:Cervical Vertebrae / Q000293:injuries* / Q000503:physiopathology* / Q000601:surgery; D020342:Finite Element Analysis; D007403:Intervertebral Disc / Q000503:physiopathology / Q000601:surgery; D007405:Intervertebral Disc Displacement / Q000503:physiopathology / Q000601:surgery; D017846:Longitudinal Ligaments / Q000503:physiopathology / Q000601:surgery; D016059:Range of Motion, Articular / Q000502:physiology; D012307:Risk Factors; D013123:Spinal Fusion; D014911:Whiplash Injuries / Q000503:physiopathology* / Q000601:surgery
keywords: Cervical spine; Extension injury; Intervertebral disc rupture; Spine simulator; Ventral spondylodesis