DYNAMIC TRUNK ALIGNMENT DURING GAIT IMPROVED AFTER EXTREME LATERAL INTERBODY FUSION IN THREE CASES WITH DEGENERATIVE LUMBAR KYPHOSCOLIOSIS

H. Matsuo¹, H. Nakajima², H. Naruse¹, K. Shoji¹, M. Kubota³, A. Takahashi^1,2, M. Tsubokawa^1,2, A. Matsumine², S. Shimada¹

Background: In patients with degenerative lumbar kyphoscoliosis (DLKS), dynamic trunk alignment during gait is worse than static trunk alignment during standing. Dynamic trunk alignment during gait would expect to improve after the extreme lateral interbody fusion (XLIF), which underwent to correct the static alignment. However, it is unclear how dynamic trunk alignment during gait in DLKS patients alters before and after XLIF.

Purpose: The purpose of the present case series is to examine how dynamic trunk alignment in DLKS patients alters before and after XLIF.

Methods: Three patients with DLKS (all females, mean age ± standard deviation [SD]: 71.0 + 7.0 years) underwent gait analysis using a three-dimensional motion analysis system before and after XLIF. Gait analysis after XLIF was performed at a month postoperatively. Five age-matched healthy females (mean age ± SD: 70.4 + 5.5 years) also performed gait analysis. A three-dimensional motion analysis system (VICON-MX; Vicon Motion Systems, Oxford, UK) consisted of ten T10 cameras (Vicon Motion Systems, Oxford, UK) and four synchronized force plates (AMTI, Watertown, MA, USA) and placed in the middle of a 10-meter walkway. Thirty-five retro-reflective markers were attached to each patient on anatomical landmarks following the Plug-in-Gait marker set. We instructed all patients to walk at their comfortable speed. The trunk alignment in the global reference frame was also obtained during both standing and gait using the software (Vicon NEXUS, Polygon 3: Vicon Motion Systems Ltd., Oxford, UK). We compared these parameters before and after XLIF. Additionally, respectively before and after XLIF, we compared trunk alignment during standing with gait.

Results: Before XLIF, the trunk was tilted anteriorly and tilted to the right (the concave side in one case and the convex side in two cases) in all cases in the standing. Furthermore, in two of the three cases, the trunk during gait showed an increased anterior tilt compared to standing. The increase in anterior trunk tilt during walking in these two cases was higher than that of the mean +2 SD in healthy female subjects. After XLIF, trunk alignment during standing and gait improved to be similar alignment of healthy female subjects in both the sagittal and frontal planes. However, in the same two cases as before XLIF, the trunk during gait remained in an increased anterior tilt compared to the standing. The increase in anterior trunk tilt during gait in these two cases was also higher than the mean + 2 SD in healthy female subjects.

Conclusion(s): We confirmed that dynamic trunk alignment during gait in all cases improved after XLIF. On the other hand, two cases were observed with residual exacerbation of anterior trunk tilt during gait compared to standing even after XLIF.

Implications: It was suggested that XLIF might improve not only static trunk alignment during standing but also dynamic trunk alignment during gait. Even after XLIF, since there are cases of exacerbated dynamic trunk alignment in gait than in standing, it was inferred that there is a need to train dynamic trunk stability in post-XLIF rehabilitation.

Funding, acknowledgements: Any funding does not support this case series.

Keywords: Degenerative lumbar kyphoscoliosis, extreme lateral interbody fusion, gait analysis

Topic: Orthopaedics

Did this work require ethics approval? No

Institution: N/A

Committee: N/A

Reason: Because, in Japan, case reports are exempt from the ethical guidelines for medical research involving human subjects.