Teng Lu1, Yi Lu2. 1. Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Department of Orthopedics, Xi'an Jiaotong University School of Medicine, Xi'an, China. 2. Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. Electronic address: yilu1945@gmail.com.
Abstract
OBJECTIVE: We compared the biomechanical differences among posterolateral fusion (PLF) and transforaminal, extreme, and oblique lumbar interbody fusion (TLIF, XLIF, and OLIF, respectively) procedures. METHODS: An intact finite element (FE) model of the L3-L5 lumbar spine was constructed. The PLF, TLIF with a banana-shaped cage, TLIF with a straight cage, XLIF, and OLIF procedures were simulated at the L4-L5 level. The range of motion (ROM) and stress peaks in the cortical endplate, cancellous bone, and posterior instrument were compared among the 5 constructs. RESULTS: The PLF construct had much greater ROM than did the other constructs (0.44°-1.05° vs. 0.28°-0.72°). The TLIF with a straight cage induced the greatest stress peaks in the endplate and cancellous bone (24.94-60.03 MPa and 0.72-1.96 MPa, respectively), followed by the TLIF with a banana-shaped cage (23.73-44.8 MPa and 0.6-1.36 MPa, respectively). The OLIF construct (16.76-32.41 MPa and 0.54-1.07 MPa, respectively) and XLIF construct (17.01-35.34 MPa and 0.56-1.12 MPa, respectively) induced much lower stress peaks in the endplate and cancellous bone. In the PLF construct, the stress peaks in the posterior instrument ranged from 244.6 to 377.4 MPa, significantly greater than those in the other constructs (123.9-237.4 MPa). CONCLUSION: The PLF had less stability than the other 3 fusion procedures owing to the greater ROM and stress peaks in the posterior instrument. The OLIF and XLIF induced fewer stress peaks in the cortical endplate and cancellous bone than did the TLIF procedure, which was beneficial for subsidence resistance and disc height and segmental angle maintenance.
OBJECTIVE: We compared the biomechanical differences among posterolateral fusion (PLF) and transforaminal, extreme, and oblique lumbar interbody fusion (TLIF, XLIF, and OLIF, respectively) procedures. METHODS: An intact finite element (FE) model of the L3-L5 lumbar spine was constructed. The PLF, TLIF with a banana-shaped cage, TLIF with a straight cage, XLIF, and OLIF procedures were simulated at the L4-L5 level. The range of motion (ROM) and stress peaks in the cortical endplate, cancellous bone, and posterior instrument were compared among the 5 constructs. RESULTS: The PLF construct had much greater ROM than did the other constructs (0.44°-1.05° vs. 0.28°-0.72°). The TLIF with a straight cage induced the greatest stress peaks in the endplate and cancellous bone (24.94-60.03 MPa and 0.72-1.96 MPa, respectively), followed by the TLIF with a banana-shaped cage (23.73-44.8 MPa and 0.6-1.36 MPa, respectively). The OLIF construct (16.76-32.41 MPa and 0.54-1.07 MPa, respectively) and XLIF construct (17.01-35.34 MPa and 0.56-1.12 MPa, respectively) induced much lower stress peaks in the endplate and cancellous bone. In the PLF construct, the stress peaks in the posterior instrument ranged from 244.6 to 377.4 MPa, significantly greater than those in the other constructs (123.9-237.4 MPa). CONCLUSION: The PLF had less stability than the other 3 fusion procedures owing to the greater ROM and stress peaks in the posterior instrument. The OLIF and XLIF induced fewer stress peaks in the cortical endplate and cancellous bone than did the TLIF procedure, which was beneficial for subsidence resistance and disc height and segmental angle maintenance.