TY - JOUR
T1 - A Lateral Expandable Cage with Independently Adjustable Anterior and Posterior Heights Can Improve the Pressure Distribution at the Cage-Endplate Interface
T2 - A Biomechanics Study
AU - Kusins, Jonathan
AU - Uyekawa, Scott
AU - Singh, Gurpreet
AU - Peng, Yun
AU - McQuarrie, Chase
AU - Holman, Paul
AU - Cheng, Ivan
AU - Jekir, Michael
N1 - Funding Information:
Conflict of interest statement: J. Kusins, S. Uyekawa, G. Singh, Y. Peng, C. McQuarrie, and M. Jekir are employees of NuVasive. P. Holman reports consulting fees from DePuy Synthes and NuVasive, fellowship support from Medtronic, and speaking fees and/or teaching arrangements from Medtronic. I. Cheng reports consulting fees from Surgalign; private investments in Cytonics and Spinalcyte; royalties from Globus Medical, NuVasive, and Spine Wave; and scientific advisory board membership at SeaSpine.
Publisher Copyright:
© 2023 Elsevier Inc.
PY - 2024/1
Y1 - 2024/1
N2 - OBJECTIVE: To investigate how the expansion trajectory of a lateral expandable cage affects pressure distribution at the cage-endplate interface under well-controlled biomechanical loading conditions.METHODS: Three unique vertical height expansion trajectories used by clinically relevant lateral expandable cages were evaluated: craniocaudal, fixed-arc, and independently adjustable anterior and posterior height expansion. Two biomechanical loading scenarios were performed. The first scenario used custom bone foam test blocks to assess resultant pressure distribution at varying test block lordotic angles and expansion heights. The second scenario simulated expansion using synthetic spine units and compared the pressure distribution following expansion.RESULTS: For an expandable cage with craniocaudal expansion, the pressure distribution at the cage-endplate interface was found to depend heavily on the lordotic angle of the test block (P < 0.001), but not expansion height (P = 0.634). The greatest maximum pressure occurred at higher test block lordotic angles. For an expandable cage with fixed-arc expansion, the pressure distribution shifted anteriorly throughout expansion. In the simulated expansion trials, an expandable cage with adjustable anterior and posterior height expansion was found to improve the pressure distribution at the cage-endplate interface, reducing the maximum pressure measurements by 22% and 14% in the craniocaudal and fixed-arc expansion, respectively.CONCLUSIONS: Of the cage designs evaluated in this study, an expandable cage with independently adjustable anterior and posterior heights lowered the maximum pressure measured at the cage-endplate interface and alleviated the potential of cage edge loading, both of which are important considerations that are fundamental for a successful fusion procedure and the mitigation of implant subsidence risk.
AB - OBJECTIVE: To investigate how the expansion trajectory of a lateral expandable cage affects pressure distribution at the cage-endplate interface under well-controlled biomechanical loading conditions.METHODS: Three unique vertical height expansion trajectories used by clinically relevant lateral expandable cages were evaluated: craniocaudal, fixed-arc, and independently adjustable anterior and posterior height expansion. Two biomechanical loading scenarios were performed. The first scenario used custom bone foam test blocks to assess resultant pressure distribution at varying test block lordotic angles and expansion heights. The second scenario simulated expansion using synthetic spine units and compared the pressure distribution following expansion.RESULTS: For an expandable cage with craniocaudal expansion, the pressure distribution at the cage-endplate interface was found to depend heavily on the lordotic angle of the test block (P < 0.001), but not expansion height (P = 0.634). The greatest maximum pressure occurred at higher test block lordotic angles. For an expandable cage with fixed-arc expansion, the pressure distribution shifted anteriorly throughout expansion. In the simulated expansion trials, an expandable cage with adjustable anterior and posterior height expansion was found to improve the pressure distribution at the cage-endplate interface, reducing the maximum pressure measurements by 22% and 14% in the craniocaudal and fixed-arc expansion, respectively.CONCLUSIONS: Of the cage designs evaluated in this study, an expandable cage with independently adjustable anterior and posterior heights lowered the maximum pressure measured at the cage-endplate interface and alleviated the potential of cage edge loading, both of which are important considerations that are fundamental for a successful fusion procedure and the mitigation of implant subsidence risk.
KW - Edge loading
KW - Expandable spinal fusion cage
KW - Fusion
KW - Lateral lumbar interbody fusion
KW - Pressure distribution
KW - Subsidence
KW - Biomechanical Phenomena
KW - Humans
KW - Prostheses and Implants
KW - Lordosis
KW - Lumbar Vertebrae
KW - Spinal Fusion/methods
UR - http://www.scopus.com/inward/record.url?scp=85178643908&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85178643908&partnerID=8YFLogxK
U2 - 10.1016/j.wneu.2023.10.118
DO - 10.1016/j.wneu.2023.10.118
M3 - Article
C2 - 37898279
AN - SCOPUS:85178643908
SN - 1878-8750
VL - 181
SP - e722-e731
JO - World neurosurgery
JF - World neurosurgery
ER -