ENDOSCOPIC VERSUS OPEN CARPAL-TUNNEL RELEASE - A COST-EFFECTIVENESS ANALYSIS

Endoscopic carpal tunnel release is a controversial procedure used in the treatment of carpal tunnel syndrome. Although endoscopic carpal tu nnel release is associated with less incisional pain and faster recove ry time than the open carpal tunnel release, opponents of endoscopic c arpal tunnel release suggest that its benefits are outweighed by its h igher complication rates from median nerve transection and transient n umbness of the fingers. Because of the huge economic and social impact of carpal tunnel syndrome in this country, we performed a cost-effect iveness analysis comparing endoscopic carpal tunnel release and open c arpal tunnel release using guidelines established by the Panel on Cost -Effectiveness in Health and Medicine of the U.S. Public Health Servic e. A decision analytic model was used to measure differences in cost a nd effectiveness-expressed as quality-adjusted life-years (QALYs)-betw een endoscopic carpal tunnel release and open carpal tunnel release. T he societal perspective was chosen, and probabilities for various outc omes for the two procedures were obtained from published randomized-co ntrolled trials. Cost data were derived from the Medicare Resource-Bas ed Relative Value Units published in the Federal Register. QALYs were obtained from two groups of health care providers using a utility-asse ssment questionnaire. Using probabilities for various outcomes from th e two published randomized-con trolled trials comparing endoscopic car pal tunnel release and open carpal tunnel release, we constructed a de cision tree to derive both the cost and the QALYs for the two procedur es. The incremental cost difference between endoscopic carpal, tunnel release and open carpal tunnel release was $46, using Medicare cost an d probabilities of various outcomes derived from a study by Brown et a l. in 1993. We calculated QALYs for five age groups-25, 35, 45, 55, 65 -assuming a life expectancy of 75 years. The marginal effectiveness (Q ALY of endoscopic carpal tunnel release minus QALY of open carpal tunn el release) ranged from 0.235 QALY for the 25-year-old age group to 0. 066 QALY for the 65-year-old age group, giving a cost-effectiveness ra tio of $195/QALY and $693/QALY, respectively. When compared with other accepted medical interventions such as breast cancer screening ($4836 /QALY) and exercise to prevent coronary heart disease ($13,508/QALY), endoscopic carpal tunnel release seems to be cost-effective. However, our sensitivity analysis indicated that the cost-effectiveness ratio w as very sensitive to a major complication such as median nerve injury. For endoscopic carpal tunnel release to be a cost-effective procedure , the incidence of median nerve injury must be one percentage point le ss for endoscopic carpal tunnel release than for open carpal tunnel re lease. Based on the data from the randomized-controlled trials, endosc opic carpal tunnel release seems to be a cost-effective procedure; how ever, before it can be recommended, greater emphasis must be given to the training of surgeons in this new technique, so that major complica tions such as median nerve injuries can be avoided. In addition, futur e studies must better define the actual incidence of nerve injuries fo r both endoscopic carpal tunnel release and open carpal tunnel release in the community setting.