INTRODUCTION: In patients with lumbar spinal canal stenosis (LCS), postural collapse has been observed in many cases, and its relation to quality of life (QOL) has been pointed out. Although previous studies have examined the relationship between QOL and the parameters measured on X-ray images in a static standing position, it must be taken into account that symptoms in patients with LCS often occur in a dynamic condition such as walking. The purpose of the current study was to investigate the relationship between QOL and dynamic spinopelvic alignment on walking in LCS patients.

METHODS: This is a cross-sectional study in a single hospital. We examined patients who admitted to our hospital as a surgical candidate between December 2016 and April 2021. This study was approved by institutional review board (approval number: general 29263). The Oswestry Disability Index (ODI) was used to evaluate QOL. The ODI consists of 10 items related to functional impairment. Then, trunk flexion/ extension and hip extension/ abduction muscle strength were measured as physical function using Mobie (Sakai Medical Co., Ltd., JAPAN) which is a hand-held dynamometer (HHD). Spinal mouse® (Index Ltd., Japan), a device which can calculate the curvature and inclination of particular segments of the spine, was used to measure the static alignment of the spine. A three-dimensional (3-D) motion analysis system, VICON MX (Vicon Motion Systems, Oxford, UK) was used to measure the dynamic spinopelvic alignment on walking. The data were collected for one gait cycle. For statistical analysis, we examined the relationship between the ODI score and above-mentioned items using Spearman's rank correlation coefficient. Furthermore, in order to investigate the influential factors on the ODI score, a stepwise multiple regression analysis was performed. SPSS statistics 26 (IBM, Chicago, IL, USA) was used for statistical processing. Statistical significance was set at p < 0.05.

RESULTS: A total of 30 subjects with LCS were participated in this study. ODI score significantly correlated with trunk extension strength (r = -0.559, p = 0.002), hip extension strength (r = -0.473, p = 0.011), maximum flexion angle of spine on walking (r = -0.551, p = 0.002) and maximum anterior tilt angle of pelvis (r = 0.528, p = 0.004). Multiple regression analysis showed that trunk extension strength (standardized β; - 0.35), maximum spinal flexion angle (standardized β; - 0.51) and hip extension strength (standardized β; - 0.40) significantly affected the ODI score, with adjusted coefficient of determination of 0.62.

DISCUSSION: The current study was the first to investigate the relationship between dynamic spinopelvic alignment and QOL in LCS patients. Our study suggested that both physical function and dynamic spinopelvic alignment play an important role to affect the QOL in the patients with LCS. Our findings may provide many insights to manage the symptom such as neurogenic intermittent claudication in the patients with LCS.