Correlation between Elbow Flexor Muscle Strength and Needle Electromyography Parameters after Musculocutaneous Nerve Injury.
10.12116/j.issn.1004-5619.2022.221104
- Author:
Dong GAO
1
;
Pei-Pei ZHUO
2
;
Dong TIAN
3
;
Dan RAN
1
;
Qing XIA
1
;
Wen-Tao XIA
1
Author Information
1. Shanghai Key Laboratory of Forensic Medicine, Key Laboratory of Forensic Science, Ministry of Justice, Shanghai Forensic Service Platform, Academy of Forensic Science, Shanghai 200063, China.
2. Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Center for Forensic Science of Shanghai Medical College, Fudan University, Shanghai 200032, China.
3. Department of Hand Surgery, Huashan Hospital, Fudan University, Shanghai 200040, China.
- Publication Type:Journal Article
- Keywords:
biceps brachii;
compound muscle action potential;
forensic medicine;
maximal voluntary contraction;
muscle strength;
musculocutaneous nerve injury;
needle electromyography;
recruitment potential
- MeSH:
Humans;
Elbow;
Electromyography;
Musculocutaneous Nerve;
Elbow Joint/physiology*;
Muscle, Skeletal;
Muscle Strength;
Peripheral Nerve Injuries
- From:
Journal of Forensic Medicine
2023;39(2):137-143
- CountryChina
- Language:English
-
Abstract:
OBJECTIVES:To explore the changes of elbow flexor muscle strength after musculocutaneous nerve injury and its correlation with needle electromyography (nEMG) parameters.
METHODS:Thirty cases of elbow flexor weakness caused by unilateral brachial plexus injury (involving musculocutaneous nerve) were collected. The elbow flexor muscle strength was evaluated by manual muscle test (MMT) based on Lovett Scale. All subjects were divided into Group A (grade 1 and grade 2, 16 cases) and Group B (grade 3 and grade 4, 14 cases) according to their elbow flexor muscle strength of injured side. The biceps brachii of the injured side and the healthy side were examined by nEMG. The latency and amplitude of the compound muscle action potential (CMAP) were recorded. The type of recruitment response, the mean number of turns and the mean amplitude of recruitment potential were recorded when the subjects performed maximal voluntary contraction. The quantitative elbow flexor muscle strength was measured by portable microFET 2 Manual Muscle Tester. The percentage of residual elbow flexor muscle strength (the ratio of quantitative muscle strength of the injured side to the healthy side) was calculated. The differences of nEMG parameters, quantitative muscle strength and residual elbow flexor muscle strength between the two groups and between the injured side and the healthy side were compared. The correlation between elbow flexor manual muscle strength classification, quantitative muscle strength and nEMG parameters was analyzed.
RESULTS:After musculocutaneous nerve injury, the percentage of residual elbow flexor muscle strength in Group B was 23.43% and that in Group A was 4.13%. Elbow flexor manual muscle strength classification was significantly correlated with the type of recruitment response, and the correlation coefficient was 0.886 (P<0.05). The quantitative elbow flexor muscle strength was correlated with the latency and amplitude of CMAP, the mean number of turns and the mean amplitude of recruitment potential, and the correlation coefficients were -0.528, 0.588, 0.465 and 0.426 (P<0.05), respectively.
CONCLUSIONS:The percentage of residual elbow flexor muscle strength can be used as the basis of muscle strength classification, and the comprehensive application of nEMG parameters can be used to infer quantitative elbow flexor muscle strength.
