Ultrasound as a first-line test in the diagnosis of carpal tunnel syndrome: a cost-effectiveness analysis.

BACKGROUND

The American Academy of Orthopaedic Surgeons (AAOS) recommends that surgeons obtain a confirmatory test in patients for whom carpal tunnel surgery is being considered. The AAOS, however, does not specify a preferred test. Ultrasound reportedly causes less patient discomfort and takes less time to perform, while maintaining comparable sensitivity and specificity to electrodiagnostic testing (EDX).

QUESTIONS/PURPOSES: We determined whether ultrasound as a first-line diagnostic test is more cost-effective than using EDX alone or using ultrasound alone: (1) when used by a general practitioner; and (2) when used by a specialist.

METHODS

A fictional population of patients was created and each patient was randomly assigned a probability of having true-positive, false-positive, true-negative, and true-positive ultrasound and EDX tests over an expected range of sensitivity and specificity values using Monte Carlo methods. Charges were assigned based on Medicare charges for diagnostic tests and estimates of missed time from work.

RESULTS

The average charge for the use of ultrasound as a first-line diagnostic test followed by EDX for confirmation of a negative ultrasound test was $562.90 per patient in the general practitioner scenario and $369.50 per patient in the specialist scenario, compared with $400.30 and $428.30 for EDX alone, respectively.

CONCLUSIONS

The use of diagnostic ultrasound as a first-line test for confirmation of a clinical diagnosis of carpal tunnel syndrome is a more cost-effective strategy in the specialist population and results in improved false-negative rates in the generalist population despite increased cost.

LEVEL OF EVIDENCE: Level III, economic and decision analyses. See the Guidelines for Authors for a complete description of levels of evidence.