Cervical HIVD Related to Long-Term Whole Body Vibration and Awkward Posture / 대한산업의학회지

BACKGROUND: The relationship between whole body vibration and awkward neck posture to cervical herniated intervertebral disc (HIVD) has been rarely reported. In this report, we present the case of an overhead crane operator, that had no known history of neck injury, but had long-term exposure to whole body vibration and improper neck posture, who developed cervical HIVD, which raises concerns over the possibility of occupational causation. CASE: A patient, operating an overhead crane since Dec 26th 1986, began to suffer from a neck pain and developed cervical HIVD in 1998. He had been frequently treated in an outpatient clinic, but the symptom was not improve. Eventually, he got HIVD surgery in Sep 6th 2007, and then the symptom was relieved. There were 4 groups and 3 shift system in the patient's overhead crane operation. He worked eight hours a day and 5 days a week. Actual crane work time was about 6 hours a day. The crane was located at 20 meters above the work field so that the crane operator had to look downward and the neck was bent by more than 20degrees for nearly the entire working day. Daily vibration exposure was expressed in terms of an 8-hour energy-equivalent frequency-weighted acceleration magnitude (A(8)) and vibration dose value (VDV). The daily A(8) was measured to be 0.23 m/s2 and the daily VDV was 7.4 m/s(1.75). Although these levels were below the action level recommended by the International Organization for Standardization (ISO) and European Commission (EC), it cannot be ignored that whole body vibration in addition to an awkward neck posture may be related to an increased risk for neck disease. A long-term awkward posture can adversely impact the prevalence of neck disease. In addition, occupational exposure to whole body vibration along with an awkward neck posture seems to exacerbate these effects. CONCLUSION: An overhead crane operator may have acquired cervical HIVD due to an occupational causation. Therefore, to elucidate the causal relationship of an improper neck posture and whole body vibration to neck diseases, further investigations need to be conducted for lager sample of overhead crane operators that were exposed to a long-term awkward neck posture and whole body vibration.

The Cervical Herniated Intervertebral Disc Presenting with False Localizing Thoracic Sensory Levels

Symptoms of compressive cervical myelopathy classically include spasticity and weakness, predominantly involving the lower extremities. Sensory abnormalities are reportedly common in the upper extremities, but are often vague or misleading. The sensory findings are usually localized 2-3 spinal segments below the actual spinal cord compression. In our current series, 3 patients presented with progressive symptoms of weakness and hyperreflexia involving the lower extremities without upper extremity symptoms and with a distant thoracic sensory level ranging from T10 to T12. All 3 patients were eventually found to have a cervical herniated intervertebral disc. The direct physical effects of compression and vascular compromise in the central cervical cord compression may be responsible for the reported abnormality at a distinct thoracic sensory level. Failure to diagnose cervical myelopathy because of the presence of a thoracic sensory level can delay appropriate treatment or lead to incorrect therapy.