Abstract

While lumbar kinematics can be measured in vivo, most measurements are invasive (such as percutaneous bone pins), provide high doses of radiation (such as biplane fluoroscopy), or are taken with the patient in a static position (such as MRIs). Recent work suggests that lumbar kinematics can be determined by dynamic measurements of epidermal strain in the lower back. This work aims to develop and examine a method of examining lumbar kinematics via optoelectronic motion capture utilizing skin-mounted markers in the lumbar region. Two studies were performed. One study examined lumbar epidermal strain in 28 asymptomatic subjects during diagnostic movements, while the second study used fresh/frozen cadavers to compare segmental lumbar kinematics as measured by both an optoelectronic motion capture system utilizing skin-mounted markers and an electromagnetic motion capture system utilizing sensors mounted to percutaneous bone pins inserted into the spinous processes. In the first study, participants had a grid-like marker set adhered to their lower back. They were instructed to perform 17 diagnostic movements, with data from three trials of each exercise being captured. Data was analyzed in MATLAB to examine segmental lumbar kinematics. Analysis shows trends consistent with expected movement patterns for asymptomatic individuals with measurement values consistent with those found in previous studies. Trends of symmetry in motion for left versus right motions were observed, as well as a trend for the return motion in a movement to be faster than the outgoing motion. In the second study, three fresh/frozen cadavers were outfitted with electromagnetic motion tracking sensors mounted to bone pins which were placed in the spinous processes of L1-S2. Each cadaver also had a similar grid-like marker set of optical motion tracking markers adhered in the lumbar region. The cadavers were moved through 10 of the same diagnostic exercises with data from seven trials from each exercise being captured. Data was analyzed in MATLAB to compare the end range of motion as measured by the optical system to the same measurements by the electromagnetic system. End ROM values showed statistically different measurements for five of the twelve segment measurements compared. Data collected in this work contributes to the establishment of normative dynamic kinematics of the lumbar spine in the asymptomatic population. It also outlines the strengths and weaknesses of the methodology utilized.

Degree

College and Department

Ira A. Fulton College of Engineering; Mechanical Engineering

Rights

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