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Int Orthop. 2016 Jun;40(6):1239-46. doi: 10.1007/s00264-016-3173-8. Epub 2016 Apr 18.

Long-term effects of placing one or two cages in instrumented posterior lumbar interbody fusion.

Author information

1
Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, Peoples Republic of China.
2
State Key Laboratory of Virtual Reality Technology and Systems, Beihang University, No. 37 Xueyuan Road, Haidian District, Beijing, 100191, Peoples Republic of China.
3
Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, Peoples Republic of China. wangyu@buaa.edu.cn.
4
Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, Peoples Republic of China. yubofan@buaa.edu.cn.
5
State Key Laboratory of Virtual Reality Technology and Systems, Beihang University, No. 37 Xueyuan Road, Haidian District, Beijing, 100191, Peoples Republic of China. yubofan@buaa.edu.cn.

Abstract

PURPOSE:

Posterior lumbar interbody fusion (PLIF) is an established surgical procedure for spine stabilization after the removal of an intervertebral disc. Researches have shown that inserting a single oblique cage has a similar immediate effect to coupled cages, and it has been proposed that single-cage PLIF is a useful alternative to traditional two-cage PLIF. However, it is not clear whether placing one or two cages represents the best choice for long-term fusion. The aim of this study is to examine how cage placement affects bone remodeling after PLIF surgery, and how this consequently impacts the long-term fusion process.

METHODS:

A finite element model of a L3-L4 lumbar spine with PLIF was developed. The spinal segment was modeled with a partial laminectomy and a discectomy with partial facetectomy, and implanted with posterior pedicle screws. Two models were analyzed, one with coupled parallel cages and one with a single oblique cage. Adaptive bone remodeling was simulated according to Huiskes' criterion.

RESULTS:

The results showed that in the initial state prior to any bone remodeling, cage stress, cage subsidence and cage dislodgement in the single cage model were all greater than in the coupled cage model. In the final state after significant bone remodeling had taken place, these parameters had decreased in both models and the differences between the two models were reduced. Also, the single cage model demonstrated superior bone development in the bone graft when placed under a constant 400 N axial compressive load.

CONCLUSION:

Based on the long-term results, instrumented PLIF with a single cage could also be encouraged in clinical practice.

KEYWORDS:

Bone remodeling; Finite element analysis (FEA); Lumbar spine model; Posterior lumbar interbody fusion (PLIF); Spinal cage

PMID:
27087626
DOI:
10.1007/s00264-016-3173-8
[Indexed for MEDLINE]

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