Alteration of gait characteristics in patients with adult spinal deformity

Abstract

Patients with Adult Spinal Deformity(ASD) have distorted spinal alignment altering their gait pattern [1–3]. However, the deformity may differ between patients previously known with adolescent idiopathic scoliosis(AIS) and ‘de novo’ or degenerative lumbar scoliosis. AIS patients often have normal sagittal alignment on static radiographs, but display postural malalignment in frontal plane [4], while DSc patients experience sagittal malalignment [2,3,5]. The purpose of this project is to compare spatiotemporal parameters(SPT) and 3D trunk kinematic waveforms of both adult patients with symptomatic idiopathic scoliosis(ISc) and adult ‘de novo’ scoliosis(DSc) patients with controls during walking. Are SPT and 3D trunk kinematic waveforms of ISc and DSc patients different from matched controls during walking? ASD patients(n=50) scheduled for long-segment spinal fusion surgery were included and divided into an ISc(n=24, median(Q1-Q3) age 20(19-27) years, leg length 0.9(0.85-0.93) m, BMI 23.1(20.7-26.7) kg/m2), and a DSc(n=26, median(Q1-Q3) age 60.5(55-66) years, leg length 0.89(0.83-0.93) m, BMI 28.1(25.1-30.1) kg/m2) group. Each patient was matched to an age-, gender-, weight- and height asymptomatic healthy control. Gait was measured while walking at comfortable speed on an instrumented treadmill with 3D motion capture system surrounded by a 180° projection screen displaying a virtual environment. The human body lower limb model with trunk markers was used[6]. 250 steps were recorded and averages over all measured steps per individual were used for analyses. SPT were presented as median(interquartile range). Independent t-test or Mann-Whitney U test was used to compare the patients with their control group. Statistical Parametric Mapping(independent t-test) was used to compare 3D trunk kinematics between the groups. Patients with ISc walked with comparable SPT to controls, whereas patients with DSc walked significantly slower(0.99(0.73-1.14) vs 1.30(1.13-1.39) m/s) with lower cadence (108.4(101.8-113.3) vs 118.3 (111.3-122.8) steps/min), smaller (1.08(0.84-1.28) vs 1.29(1.21-1.37) m) but wider steps (20(18-24) vs 16(14-20) cm), and increased stride- (1.11(1.07-1.18) vs 1.02(0.98-1.08) s), stance- (0.70(0.66-0.76) vs 0.61(0.58-0.66) s), and double support time (0.14(0.12-0.17) vs 0.11(0.09-0.13) s). Compared to their matched controls, DSc patients showed significantly increased anterior trunk tilt during the whole gait cycle, while ISc patients walked with significantly increased trunk lateroflexion during stance(0-52% gait cycle; Fig. 1). Both DSc and ISc patients had comparable trunk rotation compared to controls(Fig. 1). Fig. 1. 3D Trunk kinematic waveforms. Patients in green andcontrols in grey. Statistical Parametric Mapping statistics are presented.Download : Download high-res image (137KB)Download : Download full-size image ISc and DSc patients show different gait alterations compared to controls. ISc patients show decreased trunk lateroflexion, suggesting postural malalignment in frontal plane during walking, while DSc patients show increased anterior trunk tilt. Furthermore, DSc patients have a slower walking speed with increased stance time, smaller and wider steps, which can be linked to stability[7,8]. Future research involving dynamic spinal alignment parameters is needed to elucidate the effect of ASD on 3D kinematic waveforms.