Differences in the performance of commercially available 10-g monofilaments

OBJECTIVE - This independent study was designed to determine the accuracy o f 10-g monofilaments manufactured and supplied by popular commercial compan ies. RESEARCH DESIGN AND METHODS - A total of 160 new 10-g monofilaments (30 Sem mes-Weinstein monofilaments [North Coast Medical], 30 Timesco/Sensory Testi ng Systems monofilaments, 50 Owen Mumford Neuropens, and 50 Bailey Instrume nts monofilaments) were tested using a calibrated load cell. Each monofilam ent was subjected to 10 mechanical bucklings of 10 mm while the load cell d etected the maximum buckling force, Longevity testing was performed on a su bset of the monofilaments by subjecting them to continuous compressions unt il the buckling force was <9 g. RESULTS - The accuracy of monofilaments to produce a buckling force of 10 g varies among manufacturers. Bailey Instruments and Owen Mumford filaments were the most accurate with 100% buckling within +/-1.0 g of 10 g. Only 70% of the Semmes-Weinstein monofilaments from North Coast Medical buckled wit hin +/-1.0 g of 10 g. A total of 80% of Timesco filaments buckled at <8 g. Longevity tests on Bailey Instruments and Owen Mumford monofilaments demons trated that 80% continued to buckle within 10% of 10 g after 100 compressio ns, but only 50% were within this range after 200 compressions. The maximum amount of recovery achieved in any monofilament occurred within 24 h. CONCLUSIONS - Monofilaments made by either Bailey Instruments or Owen Mumfo rd are recommended for use in clinical practice. North Coast Medical monofi laments may operate differently in the U.S. because of different environmen tal conditions such as differences in humidity. Timesco/Sensory Testing Sys tems monofilaments were neither accurate enough nor Conformity European mar ked to recommend their use in the U.K. Longevity and recovery testing sugge st that each monofilament will survive usage on similar to 10 patients befo re needing a recovery time of 24 h before further use.