Early detection of cervical spine disorder in industrial and job related injuries

Background. There has been growing awareness among occupational health professionals worldwide over the past several years of the large number of musculoskeletal disorders (MSDs), in particular, neck and upper limb pain. Purposes. The first aim of this study was to develop a set of criteria (cervical spine tests) for subjects at high risk for cervical spine disorders. The criteria included electromyography (EMG), clinical and biomechanical assessment tools. The second aim was to develop normal values using the criteria. The third aim was to objectively evaluate the use of the criteria measures in subjects employed in ergonomic workplace environments. Methods. A total of 45 subjects participated in the study, 15 normal subjects (male and female), ages 30–50 years. Fifteen subjects with neck pain and another 15 without neck pain (male and female) who were consistent computer workers for three years were tested using the criteria. Neck ROMs were tested using the cervical range of motion (CROM) device. Muscle strength of the neck extensors and the upper trapezius muscles were tested using load cells transducer. Multi-channel surface EMG (Noraxon) was used to test the EMG parameters including the initial median frequency, median frequency slope values of the neck, at 80% and 50% of maximum voluntary isometric strength. Three repetition of each test were carried out. Data Analysis. Three one-way MANOVA were used with a post hoc analysis. This was followed by a discriminant function analysis to determine the most sensitive criteria measures that predict possible future neck disorders and could discriminate among the groups. Results. Computer workers with neck pain developed limited neck ROM in side-bend and retraction, reduced neck extensors and upper trapezius muscle strength, and increased fatigability of the neck extensors and upper trapezius muscles. Computer workers without neck pain, results showed limited ROM of neck side-bend, reduced neck extensors muscle strength, and increased fatigability of the upper trapezius muscle. The criterion discriminates successfully among the groups. EMG test of muscle fatigability of upper trapezius muscle was the most sensitive discriminate measure for detecting future neck disorders.