Clinical and radiological outcomes of dynamic cervical implant arthroplasty: A 5-year follow-up

Restoration of Range of Motion in the Cervical Spine through Single-Segment Artificial Disc Replacement Using the Baguera®C Prosthesis

Background: Anterior cervical discectomy and fusion (ACDF) is a standard procedure for degenerative diseases of the cervical spine, providing nerve decompression and spinal stabilization. However, it limits cervical spine motility, restricts fused segment activity, and may lead to adjacent degeneration. Cervical disc arthroplasty (CDA) is an accepted alternative that preserves the structure and flexibility of the cervical spine. This study aimed to explore the dynamic changes in the range of motion (ROM) of the cervical spine after CDA using a viscoelastic artificial disc, as well as the factors affecting mobility restoration. Methods: A retrospective analysis was conducted on 132 patients who underwent single-level anterior cervical discectomy and CDA from January 2015 to June 2022. Result: Analysis of data from 132 patients revealed a significant improvement in clinical outcomes. The mean ROM of C2-C7 and functional spinal unit (FSU) segments significantly increased from 2 to 36 months post-operatively. Cervical spine flexibility was preserved and enhanced after prosthesis implantation. However, it took six months for the cervical spine motility to stabilize. In addition, sex and age were found to impact motility restoration, with female and younger patients exhibiting larger ROMs post-surgery. Additionally, CDA at the C5-C6 level resulted in the greatest increase in ROM, potentially improving overall kinematic ability. Conclusions: Single-segment artificial disc arthroplasty effectively restores the ROM in degenerative cervical spine conditions.

Study on biomechanical analysis of two-level cervical Mobi-C and arthrodesis

OBJECTIVE

To investigate the range of motion (ROM) index of a two-level cervical arthroplasty.

METHODS

Seven human cadaveric spines were biomechanically examined from C2 level to T1 level under intact status and the following conditions: 2-level arthroplasty (C4-C6) employing Mobi-C devices (MM group), 2-level anterior cervical discectomy and fusions (2-ACDFs) (FF group), and both as a hybrid surgery (HS) (MF group and FM group). Multidirectional flexibility examination was conducted according to the Panjabi hybrid testing protocol. Unconstrained intact moments of ±1.5 NM were performed for axial rotation (AR) flexion/extension (FE), and lateral bending (LB).

RESULTS

No statistical differences were found between the intact spine and MM group at the operative- and adjacent-level kinematics in the three loading conditions, except that C4-C5 ROM significantly increased in the axial rotation loading (P<0.05). Compared with the intact spine, MF group led to a significant decrease at the arthrodesis segment ROM C5-C6 in the three loading (P<0.05), with corresponding significantly increased at C4-C5 in FE and AR (P<0.05). FM group resulted in a significant decrease in ROM C4-C5 (P<0.05) with corresponding significantly increased at C5-C6 in FE, AR and LB (P<0.05). There was not any difference for non-operative level kinematics between MF group and FM group and intact spine. Compared with the intact spine, FF group led to a significant decrease at the arthrodesis-levels (P<0.05) and marked increase at the non-operative level kinematics.

CONCLUSION

A two-level Mobi-C and Hybrid construct generated better biomechanical conditions. This study suggested that two-level cervical total disc replacement or HS could become an alternative approach for therapy of two-level consecutive cervical spondylosis.