scholarly journals Screws Fixation for Oblique Lateral Lumbar Interbody Fusion (OL-LIF): A Finite Element Study

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Qinjie Ling ◽  
Huanliang Zhang ◽  
Erxing He

Background. The combination of screw fixation and cage can provide stability in lumbar interbody fusion (LIF), which is an important technique to treat lumbar degeneration diseases. As the narrow surface cage is developed in oblique lateral lumbar interbody fusion (OL-LIF), screw fixation should be improved at the same time. We used the finite element (FE) method to investigate the biomechanics response by three different ways of screw fixation in OL-LIF. Methods. Using a validated FE model, OL-LIF with 3 different screw fixations was simulated, including percutaneous transverterbral screw (PTVS) fixation, percutaneous cortical bone trajectory screw (PCBTS) fixation, and percutaneous transpedical screw (PPS) fixation. Range of motion (ROM), vertebral body displacement, cage displacement, cage stress, cortical bone stress, and screw stress were compared. Results. ROM in FE models significantly decreased by 84-89% in flexion, 91-93% in extension, 78-89% in right and left lateral bending, and 73-82% in right and left axial rotation compared to the original model. The maximum displacement of the vertebral body and the cage in six motions except for the extension of model PTVS was the smallest among models. Meanwhile, the model PTVS had the higher stress of screw-rods system and also the lowest stress of cage. In all moments, the maximum stresses of the cages were lower than their yield stress. Conclusions. Three screw fixations can highly restrict the surgical functional spinal unit (FSU). PTVS provided the better stability than the other two screw fixations. It may be a good choice for OL-LIF.

2008 ◽  
Vol 20 (03) ◽  
pp. 145-151 ◽  
Author(s):  
Heng-Liang Liu ◽  
Ming-Tsung Sun ◽  
Chun-Li Lin ◽  
Hsin-Yi Cheng ◽  
Kou-Chen Wei ◽  
...  

This study investigates and compares the mechanical response of interbody and posterolateral fusion along with the transpedicular screw fixation for the degenerative spondylolisthesis under different load conditions using finite element (FE) analysis. Image processing, computer aided design (CAD), and computer aided engineering techniques were applied to build a three-dimensional model of a functional spinal unit (L4–L5) with transpedicular screw fixation for the posterolateral fusion FE model. Additionally, the intervertebral disc was replaced by two cages to represent the interbody fusion FE model. A unit moment of 1 Nm was applied on the top of L4 in different directions to simulate the flexion, extension, lateral bending, and axial rotation, respectively. The lower of L5 was fixed in all directions for constraint. The simulated results revealed that using cages obviously decreased (13%–58%) the stress imposed upon the instrumentations. The stress concentration occurred at the locking nut on the transpedicular screw head, the middle part of the bone plate, and the thread of transpedicular screw near the head. These findings were comparable to clinical observations. With the limited data, our results suggested interbody fusion in combination with transpedicular screw fixation demonstrated less stress on the instrumentations than the posterolateral fusion with only transpedicular screw fixation.


2016 ◽  
Vol 25 (5) ◽  
pp. 591-595 ◽  
Author(s):  
Hironobu Sakaura ◽  
Toshitada Miwa ◽  
Tomoya Yamashita ◽  
Yusuke Kuroda ◽  
Tetsuo Ohwada

OBJECTIVE Several biomechanical studies have demonstrated the favorable mechanical properties of the cortical bone trajectory (CBT) screw. However, no reports have examined surgical outcomes of posterior lumbar interbody fusion (PLIF) with CBT screw fixation for degenerative spondylolisthesis (DS) compared with those after PLIF using traditional pedicle screw (PS) fixation. The purposes of this study were thus to elucidate surgical outcomes after PLIF with CBT screw fixation for DS and to compare these results with those after PLIF using traditional PS fixation. METHODS Ninety-five consecutive patients underwent PLIF with CBT screw fixation for DS (CBT group; mean followup 35 months). A historical control group consisted of 82 consecutive patients who underwent PLIF with traditional PS fixation (PS group; mean follow-up 40 months). Clinical status was assessed using the Japanese Orthopaedic Association (JOA) scale score. Fusion status was assessed by dynamic plain radiographs and CT. The need for additional surgery and surgery-related complications was also evaluated. RESULTS The mean JOA score improved significantly from 13.7 points before surgery to 23.3 points at the latest follow-up in the CBT group (mean recovery rate 64.4%), compared with 14.4 points preoperatively to 22.7 points at final follow-up in the PS group (mean recovery rate 55.8%; p < 0.05). Solid spinal fusion was achieved in 84 patients from the CBT group (88.4%) and in 79 patients from the PS group (96.3%, p > 0.05). Symptomatic adjacent-segment disease developed in 3 patients from the CBT group (3.2%) compared with 9 patients from the PS group (11.0%, p < 0.05). CONCLUSIONS PLIF with CBT screw fixation for DS provided comparable improvement of clinical symptoms with PLIF using traditional PS fixation. However, the successful fusion rate tended to be lower in the CBT group than in the PS group, although the difference was not statistically significant between the 2 groups.


2020 ◽  
Author(s):  
gufang Fang ◽  
SG Chen ◽  
wda zhuang ◽  
WH Huang ◽  
Hongxun Sang

Abstract Background: The most common complication of oblique lumbar interbody fusion (OLIF) is cage subsidence. OLIF combined with internal fixation could help decrease the cage subsidence and increase the fusion rate. The aim of this study was to evaluate the biomechanical feasibility and safety in the patients undergoing OLIF surgery with anterolateral screw fixation (ASF). Methods: Based on our previous validated model , L4-L5 functional surgical models corresponding to the ASF and Bilateral pedicle screw fixation(BPSF) methods were created. A 500 N compression force was applied to the superior surface of the model to represent the upper body weight, and a 7.5 Nm moment was applied to simulate the six movement directions of the lumbar spinal model: flexion/extension, right/left lateral bending and right/left axial rotation. Finite element (FE) models were developed to compare the biomechanics of the ASF and BPSF groups. Results: Compared to the range of motion (ROM) of the intact lumbar model, that of the ASF model was decreased by 82.0% in flexion, 60.0% in extension, and the BPSF model was decreased by 86.7% in flexion, 77.3% in extension. Compared to the BPSF model, the maximum stresses of the L4 inferior endplate (IEP) and L5 superior endplate (SEP) were greatly increased in the ASF model; The contact surface between vertebrae and screw (CSVS) in the ASF model produced nearly100% more stresses than the BPSF model in all moment .Conclusions: OLIF surgery with ASF could not reduce the maximum stresses on the endplate and CSVS, which may be a potential risk factor for cage subsidence and screw loosening.


2017 ◽  
Vol 60 (6) ◽  
pp. 755-762 ◽  
Author(s):  
Young Hoon Choi ◽  
Shin Won Kwon ◽  
Jung Hyeon Moon ◽  
Chi Heon Kim ◽  
Chun Kee Chung ◽  
...  

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