The role of posterior screw fixation in single-level transforaminal lumbar interbody fusion during whole body vibration: A finite element study.

The role of posterior screw fixation in single-level transforaminal lumbar interbody fusion during whole body vibration: A finite element study.

World Neurosurg. 2018 Mar 29;:

Authors: Fan W, Guo LX

Abstract
OBJECTIVE: Very few studies have evaluated the need for supplementary instrumentation after lumbar interbody fusion under the condition of whole body vibration (WBV) that is typically present in vehicles. This study aimed to determine the effect of posterior pedicle screw fixation on dynamic response of the whole lumbar spine to vertical WBV after transforaminal lumbar interbody fusion (TLIF).
METHODS: A previously validated non-linear, osteoligamentous finite element (FE) model of the intact L1-sacrum human lumbar spine was modified to simulate single-level (L4-L5) TLIF without and with bilateral pedicle screw fixation (BPSF). Transit dynamic analysis was performed on the two developed models under a sinusoidal vertical vibration load of ±40 N and a compressive follower preload of 400 N, and then the obtained dynamic response results for the two models in terms of stresses and deformations were recorded and compared.
RESULTS: When compared with no fixation, BPSF decreased dynamic responses of the spinal levels to the vertical vibration after TLIF. At the fused level (L4-L5), vibration amplitudes of the von-Mises stresses in L4 inferior endplate and L5 superior endplate decreased due to BPSF by 48.0% and 46.4%, respectively. At other disc levels (L1-L2, L2-L3, L3-L4 and L5-S1), vibration amplitudes of the disc bulge, von-Mises stress in annulus ground substance and intradiscal pressure also produced 4.2-9.0%, 2.3-8.9% and 3.4-8.8% deceases respectively due to BPSF.
CONCLUSIONS: After TLIF, application of BPSF may be helpful in prevention of spine injury during vertical WBV.

PMID: 29605701 [PubMed - as supplied by publisher]

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