Researchers test reliability of implements used to measure osteoporotic spines

Scientists from McMaster University recently released a report addressing the reliability of two devices commonly used to measure the spines of patients with osteoporosis.

The study, which appears in the journal International Scholarly Research Network: Rheumatology, found that the reliability of digital inclinometers and flexicurve rulers remains consistent when used by one physician, and that use by more than one healthcare professional may increase their reliability, although minimally so and only to a point.

A digital inclinometer is an electronic device that measures the slope or tilt of an object - in this case, the spine - relative to the ground. A flexicurve ruler, on the other hand, measures the curves of the spine, in the way that measuring tape can be used to determine body dimensions.

The National Osteoporosis Foundation (NOF) states that an inclined or curved spine, especially one that has a pronounced stoop or hunch, is a fairly clear indicator of osteoporosis, particularly among the elderly.

This stoop occurs when the vertebrae in the spine begin to break or collapse under the pressure of an osteoporotic person's body weight. This process can be painful and significantly diminish quality of life, the NOF notes.

In the new study, researchers from McMaster's School of Rehabilitation Science used generalizability theory and classic test theory - two scientific frameworks for determining consistency - to evaluate the repeated accuracy of digital inclinometers and flexicurve rulers in measuring spine shape.

The team found that both implements are reliable when used by one diagnostician. When a single doctor used an inclinometer more than once or a ruler more than three times to measure the same spine, the instruments' consistency even improved slightly.

However, reliability could only be maintained so far once diagnoses were made by multiple professionals. Researchers noted that just two physicians could use the ruler before the consistency of its measurements began to decrease.

While the inclinometer performed better in this regard, its reliability also decreased after certain spine angles were measured by between two and five users.

The team concluded that multiple measurements by one physician may slightly increase the consistency of spinal measurements among patients with osteoporosis.