Ning Liu1, Teng Lu2, Yibin Wang3, Zhongwei Sun4, Jialiang Li3, Xijing He5. 1. Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, China; Department of Spine Surgery, Hanzhong Central Hospital, Hanzhong, Shaanxi Province, China. 2. Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, China; Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. 3. Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, China. 4. Department of Research and Development, ZSFab, Inc., Boston, Massachusetts, USA. 5. Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, China. Electronic address: he_xijing@126.com.
Abstract
BACKGROUND: For multilevel cervical fusion, anterior corpectomy and fusion (ACCF) induces more implant-related complications than anterior diskectomy and fusion (ACDF), which implies that the biomechanical stability of ACCF may be insufficient. The aim of this study was to assess whether the optimization of the cage profiles could improve the biomechanical performance of multilevel ACCF. METHODS: Three finite element models were constructed and compared, including 3-level ACDF, 2-level ACCF using a conventional cage for reconstruction, and 2-level ACCF using a new cage for reconstruction. The ends of the new cage possessed additional end rings and emulated the end plate geometries. The ranges of motion (ROMs) of the surgical segments and the stress peaks in the end plate, fixation system, and screw-bone interface were compared. RESULTS: Compared with preoperative status, ACDF and ACCF reduced the segmental ROMs by 96.1%-98.2%. The end plate stress peaks were the highest in ACCF using the conventional cage (10.1-18.6 MPa), followed by ACCF using the new cage (7.7-14.3 MPa) and ACDF (5.3-9.1 MPa). ACDF induced the highest stress peaks in the fixation system and screw-bone interface (32.5-39.3 MPa and 12.1-12.7 MPa, respectively), followed by ACCF using the conventional cage (20.4-31.7 MPa and 10.3-13.6 MPa, respectively) and ACCF using the new cage (18.6-25.7 MPa and 9.7-12.6 MPa, respectively). CONCLUSIONS: The application of the new cage decreased the risks of cage subsidence and instrument-related complications in multilevel ACCF. Under the condition where cage subsidence was prevented, ACCF was superior to ACDF in terms of construct stability and avoiding instrument-related complications.
BACKGROUND: For multilevel cervical fusion, anterior corpectomy and fusion (ACCF) induces more implant-related complications than anterior diskectomy and fusion (ACDF), which implies that the biomechanical stability of ACCF may be insufficient. The aim of this study was to assess whether the optimization of the cage profiles could improve the biomechanical performance of multilevel ACCF. METHODS: Three finite element models were constructed and compared, including 3-level ACDF, 2-level ACCF using a conventional cage for reconstruction, and 2-level ACCF using a new cage for reconstruction. The ends of the new cage possessed additional end rings and emulated the end plate geometries. The ranges of motion (ROMs) of the surgical segments and the stress peaks in the end plate, fixation system, and screw-bone interface were compared. RESULTS: Compared with preoperative status, ACDF and ACCF reduced the segmental ROMs by 96.1%-98.2%. The end plate stress peaks were the highest in ACCF using the conventional cage (10.1-18.6 MPa), followed by ACCF using the new cage (7.7-14.3 MPa) and ACDF (5.3-9.1 MPa). ACDF induced the highest stress peaks in the fixation system and screw-bone interface (32.5-39.3 MPa and 12.1-12.7 MPa, respectively), followed by ACCF using the conventional cage (20.4-31.7 MPa and 10.3-13.6 MPa, respectively) and ACCF using the new cage (18.6-25.7 MPa and 9.7-12.6 MPa, respectively). CONCLUSIONS: The application of the new cage decreased the risks of cage subsidence and instrument-related complications in multilevel ACCF. Under the condition where cage subsidence was prevented, ACCF was superior to ACDF in terms of construct stability and avoiding instrument-related complications.
Authors: Charles Tatter; Oscar Persson; Gustav Burström; Erik Edström; Adrian Elmi-Terander Journal: Oper Neurosurg (Hagerstown) Date: 2020-12-15 Impact factor: 2.703