Kinematics and paraspinal muscle activation patterns during walking differ between patients with lumbar spinal stenosis and controls

BACKGROUND

The narrowing of the spinal canal due to degenerative processes may lead to symptomatic lumbar spinal stenosis (sLSS) and impairments in the patients' gait. Changes in lower extremity joint kinematics and trunk flexion angles have been reported, yet less is known about muscle activation patterns of paraspinal and gluteal muscles in patients with sLSS compared to healthy participants.

RESEARCH QUESTION

Do muscle activation patterns together with sagittal joint kinematics differ between patients with sLSS and healthy controls and do these differences-quantified using gait scores-correlate with clinical scores?

METHODS

In 20 patients with sLSS scheduled for surgery and 19 healthy participants, gait was assessed using seven inertial sensors and muscle activation of gluteus medius, erector spinae and multifidus using wireless surface electromyography (EMG). Differences in joint kinematics and EMG patterns were assessed using statistical parametric mapping with non-parametric independent sample t tests (P < 0.05). Gait scores that describe the overall deviation in joint angles (mGPS) and muscle activation patterns (EMG-Profile Score) were calculated as root mean square distances between patients and healthy participants and their associations with clinical scores (pain, Oswestry Disability Score (ODI)) were analyzed using Spearman's correlation coefficients rho (P < 0.05).

RESULTS

Patients had larger mGPS (+1.9°) and EMG-Profile Scores (+50%) and walked on average slower (-0.26 m/s) than controls. EMG patterns revealed higher activation of multifidus, erector spinae and gluteus medius during midstance in patients compared to controls. Clinical scores (pain, ODI) did not correlate with mGPS or EMG-Profile Scores within patients.

SIGNIFICANCE

Observed differences in gait and muscle activation patterns and in the summary scores of gait and EMG deviations between patients with sLSS and healthy controls may represent additional functional outcomes reflecting the functional status of patients that can be measured using wearable sensors and hence is suitable for application in clinical practice.

A Meta-Analysis on the Clinical Significance of Redundant Nerve Roots in Symptomatic Lumbar Spinal Stenosis

OBJECTIVE

Symptomatic lumbar spinal stenosis (LSS), which leads to severe socioeconomic consequences and places a heavy burden on global healthcare system, is a relatively frequent spine disorder. Redundant nerve roots (RNRs) are a relatively common finding in which slender, serpiginous, or tortuous nerve roots are found in the subarachnoid space of the lumbar spine. Previous studies that evaluated the prognostic assessment of RNRs in patients with symptomatic LSS are composed of doubtful results. Therefore, the clinical significance of RNRs in symptomatic LSS is still uncertain. The aim of this meta-analysis is a systematic assessment of the clinical significance of RNR syndrome in symptomatic LSS.

METHODS

This study used a highly sensitive search strategy to identify all published studies in multiple databases up to January 1, 2017. All identified trials were systematically evaluated using specific inclusion and exclusion criteria. Cochrane methodology was also applied to the results of this study.

RESULTS

This study identified 4 relevant studies involving 297 patients. Compared with a non-RNR group, the RNR group results included worse clinical outcomes that were assessed using the Japanese Orthopedic Association scores after surgery (weighted mean difference [WMD], -0.78; 95% confidence interval [CI], -1.26 to -0.29; P = 0.002; I² = 0%), for recovery rate (WMD, -9.87; 95% CI, -15.07 to -4.67; P = 0.0002; I² = 0%), and for older age (WMD, 2.51; 95% CI, 0.45-4.57; P = 0.02; I² = 43%).

CONCLUSIONS

RNR is an entity in association with symptomatic LSS, which may be viewed as a potentially powerful prognostic indicator of worse postoperative functional recovery for symptomatic LSS.