Electromyographic Discrepancy in Paravertebral Muscle Activity Predicts Early Curve Progression of Untreated Adolescent Idiopathic Scoliosis

Study Design This study adopted a prospective cohort study design. Purpose This study aimed to examine electromyogram (EMG) discrepancy in paravertebral muscle activity and scoliosis progression, determine how vertebral morphology and EMG discrepancy evolve during scoliosis progression, and identify...

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Main Authors: Yunli Fan, Michael Kai-Tsun To, Eric Hiu Kwong Yeung, Guan-Ming Kuang, Ruixin Liang, Jason Pui Yin Cheung
Format: Article
Language:English
Published: Korean Spine Society 2023-10-01
Series:Asian Spine Journal
Subjects:
Online Access:http://www.asianspinejournal.org/upload/pdf/asj-2023-0199.pdf
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author Yunli Fan
Michael Kai-Tsun To
Eric Hiu Kwong Yeung
Guan-Ming Kuang
Ruixin Liang
Jason Pui Yin Cheung
author_facet Yunli Fan
Michael Kai-Tsun To
Eric Hiu Kwong Yeung
Guan-Ming Kuang
Ruixin Liang
Jason Pui Yin Cheung
author_sort Yunli Fan
collection DOAJ
description Study Design This study adopted a prospective cohort study design. Purpose This study aimed to examine electromyogram (EMG) discrepancy in paravertebral muscle activity and scoliosis progression, determine how vertebral morphology and EMG discrepancy evolve during scoliosis progression, and identify differences in EMG activity between individuals with and without adolescent idiopathic scoliosis (AIS). Overview of Literature Higher EMG activity is observed in the convex side of scoliotic curves, but not in populations without scoliosis, suggesting that higher EMG activity is a causative factor for curve progression. Methods In this study, 267 matched pairs of AIS and controls were recruited. The participants underwent EMG measurements at their first presentation and did not receive any treatment for 6 months at which point they underwent EMG and radiographs. Early curve progression was defined as >5° in Cobb angle at 6 months. The root mean square of the EMG (rms-EMG) signal was recorded with the participants in sitting and back extension. The rms-EMG ratio at the upper end vertebrae, apical vertebrae (AV), and lower end vertebrae (LEV) of the major curve was calculated. Results The rms-EMG ratio in the scoliosis cohort was high compared with that in the controls (sitting: 1.2±0.3 vs. 1.0±0.1, p<0.01; back extension: 1.1±0.2 vs. 1.0±0.1, p<0.01). An AV rms-EMG ratio in back extension, with a cutoff threshold of ≥1.5 in the major thoracic curve and ≥1.3 in the major lumbar curve, was a risk factor for early curve progression after 6 months without treatment (odds ratio, 4.1; 95% confidence interval, 2.8–5.9; p<0.01). Increases in side deviation (SD) (distance between the AV and the central sacral line) were related to a higher rms-EMG ratio in LEV of the major thoracic curve (baseline: rs=0.2, p=0.03; 6 months: rs=0.3, p<0.01). Conclusions An EMG discrepancy was detected in the scoliosis cohort, which was related to increases in SD in the major thoracic curve. The AV rms-EMG ratio in back extension was correlated with curve progression after 6 months of no treatment.
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spelling doaj.art-128a06d3d08b479f9a137c43688b19622023-10-31T08:19:30ZengKorean Spine SocietyAsian Spine Journal1976-19021976-78462023-10-0117592293210.31616/asj.2023.01991563Electromyographic Discrepancy in Paravertebral Muscle Activity Predicts Early Curve Progression of Untreated Adolescent Idiopathic ScoliosisYunli Fan0Michael Kai-Tsun To1Eric Hiu Kwong Yeung2Guan-Ming Kuang3Ruixin Liang4Jason Pui Yin Cheung5 Department of Physiotherapy, The University of Hong Kong–Shenzhen Hospital, Shenzhen, China Department of Orthopaedics & Traumatology, The University of Hong Kong, Hong Kong SAR, China Department of Physiotherapy, The University of Hong Kong–Shenzhen Hospital, Shenzhen, China Department of Orthopaedics, The University of Hong Kong–Shenzhen Hospital, Shenzhen, China Laboratory for Artificial Intelligence in Design, Hong Kong SAR, China Department of Orthopaedics & Traumatology, The University of Hong Kong, Hong Kong SAR, ChinaStudy Design This study adopted a prospective cohort study design. Purpose This study aimed to examine electromyogram (EMG) discrepancy in paravertebral muscle activity and scoliosis progression, determine how vertebral morphology and EMG discrepancy evolve during scoliosis progression, and identify differences in EMG activity between individuals with and without adolescent idiopathic scoliosis (AIS). Overview of Literature Higher EMG activity is observed in the convex side of scoliotic curves, but not in populations without scoliosis, suggesting that higher EMG activity is a causative factor for curve progression. Methods In this study, 267 matched pairs of AIS and controls were recruited. The participants underwent EMG measurements at their first presentation and did not receive any treatment for 6 months at which point they underwent EMG and radiographs. Early curve progression was defined as >5° in Cobb angle at 6 months. The root mean square of the EMG (rms-EMG) signal was recorded with the participants in sitting and back extension. The rms-EMG ratio at the upper end vertebrae, apical vertebrae (AV), and lower end vertebrae (LEV) of the major curve was calculated. Results The rms-EMG ratio in the scoliosis cohort was high compared with that in the controls (sitting: 1.2±0.3 vs. 1.0±0.1, p<0.01; back extension: 1.1±0.2 vs. 1.0±0.1, p<0.01). An AV rms-EMG ratio in back extension, with a cutoff threshold of ≥1.5 in the major thoracic curve and ≥1.3 in the major lumbar curve, was a risk factor for early curve progression after 6 months without treatment (odds ratio, 4.1; 95% confidence interval, 2.8–5.9; p<0.01). Increases in side deviation (SD) (distance between the AV and the central sacral line) were related to a higher rms-EMG ratio in LEV of the major thoracic curve (baseline: rs=0.2, p=0.03; 6 months: rs=0.3, p<0.01). Conclusions An EMG discrepancy was detected in the scoliosis cohort, which was related to increases in SD in the major thoracic curve. The AV rms-EMG ratio in back extension was correlated with curve progression after 6 months of no treatment.http://www.asianspinejournal.org/upload/pdf/asj-2023-0199.pdfspinescoliosiselectromyography
spellingShingle Yunli Fan
Michael Kai-Tsun To
Eric Hiu Kwong Yeung
Guan-Ming Kuang
Ruixin Liang
Jason Pui Yin Cheung
Electromyographic Discrepancy in Paravertebral Muscle Activity Predicts Early Curve Progression of Untreated Adolescent Idiopathic Scoliosis
Asian Spine Journal
spine
scoliosis
electromyography
title Electromyographic Discrepancy in Paravertebral Muscle Activity Predicts Early Curve Progression of Untreated Adolescent Idiopathic Scoliosis
title_full Electromyographic Discrepancy in Paravertebral Muscle Activity Predicts Early Curve Progression of Untreated Adolescent Idiopathic Scoliosis
title_fullStr Electromyographic Discrepancy in Paravertebral Muscle Activity Predicts Early Curve Progression of Untreated Adolescent Idiopathic Scoliosis
title_full_unstemmed Electromyographic Discrepancy in Paravertebral Muscle Activity Predicts Early Curve Progression of Untreated Adolescent Idiopathic Scoliosis
title_short Electromyographic Discrepancy in Paravertebral Muscle Activity Predicts Early Curve Progression of Untreated Adolescent Idiopathic Scoliosis
title_sort electromyographic discrepancy in paravertebral muscle activity predicts early curve progression of untreated adolescent idiopathic scoliosis
topic spine
scoliosis
electromyography
url http://www.asianspinejournal.org/upload/pdf/asj-2023-0199.pdf
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