MRI-based Endplate Bone Quality score independently predicts cage subsidence following transforaminal lumbar interbody fusion

Qian Chen; Youwei Ai; Yong Huang; Qiujiang Li; Juehan Wang; Hong Ding; Ce Zhu; Ganjun Feng; Limin Liu

doi:10.1016/j.spinee.2023.07.002

MRI-based Endplate Bone Quality score independently predicts cage subsidence following transforaminal lumbar interbody fusion

Spine J. 2023 Nov;23(11):1652-1658. doi: 10.1016/j.spinee.2023.07.002. Epub 2023 Jul 11.

Authors

Qian Chen¹, Youwei Ai², Yong Huang², Qiujiang Li², Juehan Wang², Hong Ding², Ce Zhu², Ganjun Feng², Limin Liu³

Affiliations

¹ Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital, Sichuan University, No.37 Guoxue alley, Chengdu 610041, Sichuan, China; Department of Orthopaedics and Laboratory of Biological Tissue, Engineering and Digital Medicine, Affiliated Hospital of North Sichuan Medical College, No. 1 South Maoyuan Road, Nanchong 637000, Sichuan, China.
² Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital, Sichuan University, No.37 Guoxue alley, Chengdu 610041, Sichuan, China.
³ Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital, Sichuan University, No.37 Guoxue alley, Chengdu 610041, Sichuan, China. Electronic address: liulimin_spine@163.com.

PMID: 37442209
DOI: 10.1016/j.spinee.2023.07.002

Abstract

Background context: Cage subsidence following transforaminal lumbar interbody fusion (TLIF) has closely correlated with poor vertebral bone quality. Studies have shown better predictive value for cage subsidence by measuring bone density at specific site. However, few studies have been performed to examine the relationship between site-specific MRI bone assessment and cage subsidence in patients who have undergone lumbar interbody fusion. The association between MRI-based assessment of endplate bone quality and cage subsidence after TLIF remains unclear.

Purpose: To study the predictive value of MRI-based endplate bone quality (EBQ) score for cage subsidence following TLIF, using QCT bone densitometry as a reference standard.

Study design/setting: A retrospective study.

Patient sample: A total of 280 adult patients undergoing single-segment TLIF for degenerative lumbar spine disease from 2010 to 2020 at our institution who had preoperative T1-weighted MRIs.

Outcome measures: Cage subsidence, disc height, endplate bone quality (EBQ) score, bone mineral density, fusion rate.

Methods: The retrospective study reviewed patients who underwent TLIF at one institution between March 2010 and October 2020. Cage subsidence was measured with postoperative lumbar X-rays based on the cage protrusion through into the superior or inferior end plate or both by more than 2 mm. The EBQ score was measured from preoperative T1-weighted MRI in accordance with the previously reported method.

Results: Cage subsidence was observed in 42 of the 280 patients. Bone densitometry with quantitative computed tomography was visibly reduced in the subsidence group. The mean EBQ scores of the lumbar endplate bone was 4.3±0.9 in nonsubsidence and 5.0±0.6 in subsidence. On multivariate logistic regression, the difference between the two groups was remarkable. Risk of cage subsidence increases significantly with higher EBQ scores (odds ratio [OR]=2.063, 95% confidence interval [CI] 1.365-3.120, p=.001) and was an independent factor in predicting subsidence after TLIF. On receiver operating characteristic curve, the AUC for the EBQ score was 0.820 (95% confidence interval [CI]: 0.755-0.844) and the most suitable threshold for the EBQ score was 4.730 (sensitivity: 76.2%, specificity: 83.2%).

Conclusions: Higher EBQ scores measured on preoperative MRI correlated significantly with cage subsidence following TLIF. Performing EBQ assessment prior to TLIF may be a valid method of predicting the risk of postoperative subsidence.

Keywords: Bone mineral density; Cage subsidence; EBQ; Endplate; MRI; TLIF; VBQ.