Adequate Restoration of Disc Height and Segmental Lordosis by Lumbar Interbody Fusion Decreases Adjacent Segment Degeneration

Haijun Tian; Aimin Wu; Mingke Guo; Kai Zhang; Chen Chen; Xunlin Li; Xiaofei Cheng; Tangjun Zhou; Samuel S Murray; Xiaojiang Sun; Jie Zhao

doi:10.1016/j.wneu.2018.07.075

Adequate Restoration of Disc Height and Segmental Lordosis by Lumbar Interbody Fusion Decreases Adjacent Segment Degeneration

World Neurosurg. 2018 Oct:118:e856-e864. doi: 10.1016/j.wneu.2018.07.075. Epub 2018 Jul 18.

Authors

Haijun Tian¹, Aimin Wu¹, Mingke Guo², Kai Zhang¹, Chen Chen¹, Xunlin Li¹, Xiaofei Cheng¹, Tangjun Zhou¹, Samuel S Murray³, Xiaojiang Sun⁴, Jie Zhao⁵

Affiliations

¹ Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
² Department of Orthopaedic Surgery, PLA 260 Hospital, Shijiazhuang, China.
³ Department of Medicine, University of California, Los Angeles, Los Angeles, USA; Research Service, VA Greater Los Angeles Healthcare System, North Hills, California, USA; Geriatric Research, Education and Clinical Center, VA Greater Los Angeles Healthcare System, North Hills, California, USA.
⁴ Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Electronic address: sxj603@126.com.
⁵ Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Electronic address: profzhaojie@126.com.

PMID: 30031179
DOI: 10.1016/j.wneu.2018.07.075

Abstract

Objective: This study aimed to investigate the effects of lumbar interbody fusion-induced biomechanical changes on the adjacent segments, especially disc height and segmental lordosis restoration, and to provide more information for proper surgical strategy selection.

Methods: The medical records of 528 patients who underwent posterior lumbar interbody fusion were retrospectively reviewed, and a total of 89 patients were included. Surgical indications included degenerative spondylolisthesis (nonspondylolytic), marked disc herniation, or lumbar spinal stenosis requiring extensive decompression at L4/5. Postoperative adjacent segment degeneration (ASD) was assessed based on X-rays and functional status. Disc height, foraminal height, segmental lordosis, lumbar lordosis, and cage geometry were compared between the ASD and non-ASD patients. To identify the possible risk factors for radiographic ASD, univariate analysis was performed first, followed by multivariate logistic regression using variables with P < 0.20.

Results: Univariate analysis revealed that the postoperative disc height in the non-ASD group were significantly greater than in the ASD group. The postoperative segmental lordosis in the non-ASD group was significantly greater than that in the ASD group, and the lumbar lordosis in the non-ASD group was also significantly greater than that in the ASD group at the final follow-up visit. Four variables were identified as independent risk factors for ASD by subsequent multivariate logistic regression: postoperative relative disc height of L4/5 (P = 0.011), postoperative segmental lordosis (P = 0.046), lumbar lordosis at the final follow-up visit (P = 0.007), and cage height (P = 0.038).

Conclusions: Improved lumbar lordosis is correlated with a lower incidence of ASD, and adequate disc height and segmental lordosis restoration are essential for ASD prevention.

Keywords: Adjacent segment degeneration; Degenerative lumbar disorder; Disc height; Lumbar interbody fusion; Segmental lordosis.

MeSH terms

Adult
Aged
Female
Follow-Up Studies
Humans
Intervertebral Disc / diagnostic imaging
Intervertebral Disc / surgery*
Intervertebral Disc Displacement / diagnostic imaging
Intervertebral Disc Displacement / surgery*
Lordosis / diagnostic imaging
Lordosis / surgery*
Lumbar Vertebrae / diagnostic imaging
Lumbar Vertebrae / surgery*
Male
Middle Aged
Retrospective Studies
Spinal Fusion / methods*