Background: Range of motion (ROM) is a parameter of prime importance for clinical assessment of spinal function. Many spinal ROM assessment techniques of varying reliability are currently in use. Immobilization of the pelvis and lower extremities improves control of the neutral position and decreases the error resulting from compensatory hip motion during measurement. To present a prototypic station for active 3-dimensional spinal ROM assessment; to analyze repeatability of measurements and reproducibility of the neutral position.
Methods: A quintuple 3-dimensional measurement of the lumbar and thoracic active range of motion in 12 healthy volunteers.
Results: The series of results obtained for each subject fulfilled the criteria of a normal distribution. The mean values of thoracic ROM were as follows: sagittal 40.1 degrees (SD=5.56 degrees; mean coefficient of variation CV=13.88%); horizontal 75.2 degrees (SD=6.01 degrees; CV=7.99%); frontal 34.0 degrees (SD=3.01 degrees; CV=8.84%). The mean values of lumbar ROM were as follows: sagittal 112.0 degrees (SD=4.13; CV=3.68%); horizontal 14.8 degrees (SD=3.77 degrees; CV=25.45%); frontal 67.6 degrees (SD=2.72 degrees; CV=4.03%). Inter-class correlation coefficients for particular subjects ranged between 0.95 and 0.99 (p<0.0001). Mean reproducibility of the neutral position was 1.08 degrees-2.63 degrees in thoracic spine and 1.23 degrees-2.31 degrees in lumbar spine. Comparison of the results with literature data revealed good neutral position reproducibility and high values of inter-class correlation coefficients in the present study. Potential reasons for assessment errors are discussed. Recommendations for the construction of an improved immobilizer for diagnostic purposes are presented.
Conclusions: Validated spinal ROM measurements are useful in monitoring patients with musculoskeletal disorders. Immobilization of the pelvis and lower limbs improves repeatability of thoracic and lumbar ROM assessment and reproducibility of a neutral position. The prototype enables highly repeatable measurements, but requires technical improvements.