Objective: To describe how clinical practice in those who underwent carpal tunnel release (CTR) matched the American Association of Electrodiagnostic Medicine (AAEM) 1993 practice parameters for electrodiagnostic evaluation of carpal tunnel syndrome (CTS).
Design: Cohort study using 1998-1999 Medicare billing data.
Setting: Washington State.
Participants: State Medicare beneficiaries who underwent CTR in 1999 (N=1567) Interventions Not applicable.
Main outcome measures: Compliance with the AAEM practice parameters.
Results: Of the 1567 [corrected] receiving surgery, 324 [corrected] (20.7%) did not have any electrodiagnostic testing before surgery. One hundred seventy-one (10.9%) had testing performed that did not lead to the diagnosis of CTS. One thousand seventy-two (68.4%) patients were diagnosed with CTS through electrodiagnostic testing; 155 (9.9%) had less than 2 sensory nerves studied, 114 (7.3%) had less than 2 motor nerves studied, and 65 (4.2%) of the studies met neither the standard (sensory nerve testing) nor guideline (motor nerve testing). In a multivariate analysis, neurologists were more likely than physiatrists not to meet the AAEM standards (adjusted relative risk [adj RR]=1.61; 95% confidence interval [CI], 1.13-2.31) and patients living in rural areas were more likely to have no or inadequate testing (adj RR=1.6; 95% CI, 1.3-1.9).
Conclusions: Over one third of Medicare patients undergoing CTR in Washington State in 1999 may have had an inappropriate electrodiagnostic workup before the surgery. Policymakers should consider mandating an appropriate electrodiagnostic test before approving CTR.