Wearable Sensor-Based Estimation of Spinal Loading in the Sagittal Plane during Fluoroscopic Procedures

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Brost, Samuel
Wearable Sensors , Spine Modelling , Fluoroscopic Procedures , Spine Equivalent Beam , Cumulative Loading
Back injuries are one of the most common injuries and lead to significant amounts of lost work and years spent living with disability. It is essential to understand back-related work injuries by understanding the loading that exists within the spine. Unfortunately, within the healthcare sectors where there are high rates of back injury, there is no method to measure the loading. In fluoroscopic procedures, which require the use of X-rays, healthcare workers wear heavy protective equipment for long periods, while often in poor postures. The objective of this thesis was the design and development of a system capable of measuring sagittal plane spinal kinematics using inertial measurement units and modelling the spine based on the kinematics and limited individual-specific inputs to estimate cumulative spinal loading of healthcare staff performing fluoroscopic procedures. We first developed a wearable inertial measurement unit-based sagittal plane kinematic model that uses four inertial measurement units placed on the spine. We then developed a cervical spine model based on a thoracolumbar spine equivalent beam model. After developing the cervical model, the thoracolumbar model was modified to allow for the two sections to be combined. To verify the performance of the model in the desired environment, we performed, to our knowledge, the first estimations of cumulative spinal loading during fluoroscopic interventional and operative procedures. Ten healthcare workers from cardiology and orthopaedics were recorded performing fluoroscopic procedures. They were found to have quasi-static peak compression loading less than the 3400 N limit set by the National Institute for Occupational Safety and Health. A modified Mainz-Dortmund Dose model [1] was applied to calculate the daily cumulative load dose and found that eight participants exceeded recommended sex-based limits for daily loading at the L4/L5 intervertebrae region. The primary contribution of this work is the development of a sagittal plane spinal loading model capable of estimating cumulative loads through the entire spine from L5 to C1 using inertial measurement units and a spine equivalent beam method. This model allowed for the first investigation of cumulative loading of healthcare workers during live fluoroscopic procedures.
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