Kinematische Untersuchung des Wirbelsäulensegments C4/C5 mittels Rotationsachsen vor und nach Einbau von Bandscheibenprothesen
by Constantin Alexander Hemprich
Date of Examination:2024-11-22
Date of issue:2024-10-11
Advisor:Prof. Dr. Lukas Weiser
Referee:Prof. Dr. Lukas Weiser
Referee:Prof. Dr. Christian von der Brelie
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Abstract
English
Cervical disc herniations and degenerative changes in the cervical spine are common causes of neck pain and hold significant medical relevance. In addition to conservative treatment methods, anterior cervical discectomy and fusion (ACDF) is considered the gold standard surgical treatment. This procedure involves removing the affected disc and fusing the segment, which, however, carries the risk of adjacent segment disease (ASD), a degenerative change in neighboring segments. As an alternative, motion-preserving disc prostheses (total disc arthroplasty, TDA) have been developed, aiming to maintain physiological kinematics and reduce the risk of ASD. The present study investigates the biomechanical effects of two prosthesis types, Baguera®C Cervical Disc Prosthesis (Spineart, Plan-les-Ouates, Switzerland, TDA-BAG) and Rhine® Cervical Disc System (K2M Inc., Leesburg, Virginia, USA, TDA-RHI), on the kinematics of the C4/C5 vertebral segment. Using ten human cervical spine specimens, the instantaneous helical axis (IHA) was analyzed under intact conditions and after TDA including the impact of decentralized preloads. The results show that both prostheses alter the segment's kinematics, particularly under lateral preload, with the TDA-RHI showing greater deviations from natural kinematics than the TDA-BAG. Despite preserving some range of motion after TDA, a complete imitation of natural segment kinematics is not achievable, suggesting potential long-term consequences such as ASD.
Keywords: cervical spine; instantaneous helical axis; total disc arthroplasty; cervical disc; range of motion; functional spinal unit