Improving the evaluation of benign low back pain.

STUDY DESIGN: A prospective, blind study was conducted to investigate the factors underlying the decisions of expert clinicians in diagnosis of acute, benign low back pain, compared with results obtained with an automated physical examination by machine. From the results, a strategy to significantly improve clinical diagnosis in cases of discordance was determined.

OBJECTIVES: To identify factors in the clinical assessment of low back pain that indicate when independent diagnostic testing would be useful.

SUMMARY OF BACKGROUND DATA: The clinical evaluation of low back pain is often dominated by subjective reports of pain. Published medical literature has underscored several inherent weaknesses of the clinical examination, and concerns have been raised about its effectiveness for assessing patients with low back pain. Thus, it has been proposed that objective measures to complement the clinician's examination would be beneficial in the formulation of dependable diagnoses.

METHODS: Randomly designated subjects, who in describing their conditions were objective or role playing, were assessed by clinicians and a machine for diagnosis of low back pain assessment versus normal backs. Each subject's pain assessment was compared with a gold standard that was established by experts in low back pain. Components of the clinical examination were analyzed to assess which were the most informative in making a reliable diagnosis. The information content of the machine assessment was also analyzed and a strategy to complement the clinical diagnosis with the machine diagnosis determined.

RESULTS: Discordance among the various components of the clinical examination was a strong indicator of when the efficacy of the clinical examination dropped below a random level of decision making. When there was discordance, incorporating the functional evaluation by machine into the clinical diagnosis improved the performance of the clinician. Notably, in nonobjective subjects, the accuracy of diagnosis was enhanced by as much as 69%.

CONCLUSIONS: It is possible to improve the accuracy of clinical diagnosis by incorporating a functional evaluation by machine when there is discordance between physical examination findings and reported pain.