An investigation of a cluster of cervical herniated discs among container truck drivers with occupational exposure to whole-body vibration.

OBJECTIVE This study aimed to determine if occupational exposure to whole-body vibration is associated with cervical intervertebral disc herniation among container truck drivers. METHODS We conducted a walk-through survey among container truck drivers and unexposed workers. We also measured the vibration hazard of the container truck over the driver's back and seat when the driver was loading a container and driving the loaded truck. RESULTS AND DISCUSSION Among the 38 workers interviewed, 32 were container truck drivers. Four of them reported cervical herniated discs, and all of these individuals were container truck drivers with a job tenure of greater than 10 years. Self-reported cervical herniated disc, nuchal pain, nocturia, arm/forearm weakness, arm/forearm numbness, and finger numbness were significantly more prevalent as the driver's duration of exposure increased (all p values of test for trend <0.05). The vibration of the truck during and after loading a container was considered the main cause of herniated disc. When a container truck was driven with a loaded container, both the vertical and horizontal vibrating acceleration over the seat and back sites exceeded the 8-hr exposure level based on the ISO 2631-1 criteria. The transient vibration dose values (VDVs) measured during misaligned or unsmooth loading operations were usually greater than the upper bounds of the health guidance caution zone for the 8-hr VDV. CONCLUSIONS Our investigation disclosed a cluster of cervical intervertebral disc herniation that was associated with the vibration hazard during long-term container truck driving under full load and possibly aggravated by misaligned loading operations.