Physiological considerations in functional 3-D lumbar diagnosis: Non-physiological tests

Lumbar spine function may be clinically assessed by subjective physician findings or by a more sophisticated mean such as 3-D dynamometric system. This system was developed to differentiate objectively between physiologic and non-physiological behavior of LBP patients. The same system is used, concurrently, to categorize the physiologic tests according to functional limitation. The four major parameters used for assessing spinal disability are: range of motion, maximal isometric torque, maximal velocity and maximal torque in the secondary axis. Six other independent parameters were used in order to assess non-cooperative or non-physiologic behavior. For the study, 108 non-symptomatic subjects and 595 LBP patients were tested. All patients had a physical examination before being tested on the dynamometric device (the IsoStation B-200). One hundred and ten patients were classified as non-physiological and 91 were classified in the gray zone. The results support the use of 3-D dynamometry to objectively classify the patient's performance reliability. The measured parameters are objective and reliable indicators of the patient's physical condition and credibility that should influence both the patient's assessment and treatment.