How to measure vessel caliber in microsurgery and super-microsurgery? Metrological study of three methods applicable in clinical practice

Abstract

The microsurgical literature reports the vascular calibers of the vessels studied even though the method of measurement of these vessels is very rarely reported. We performed a metrological study evaluating three methods to measure the external calibers of catheters corresponding to microsurgical and super-microsurgical vessels (1.2mm, 0.8mm, and 0.6mm). Six evaluators measured 15 catheters of three different hidden diameters by each of the three methods applicable in clinical practice: standard graduated ruler, Shinwa® micrometric ruler, and ImageJ® software from a photograph. Accuracy and reliability of the measurements were assessed by studying the inter- and intra-rater and inter-method coefficients (variants of the intra-class coefficient (ICC)) and analysis of the IC95% of the ICCs. Intra class correlation ICC "intra-rater" coefficient finds for the standard rule 0.81 [0.65-0.93], Shinwa® rule 0.86 [0.67-0.96], and for the ImageJ® software 0.97 [0.94-0.99]. The "Inter-rater" ICC shows respectively the coefficient 0.51 [0.23 and max 0.93], 0.87 [0.75-0.95], and 0.95 [0.89-0.98]. It appears that the graduated decimeter is the least reliable method of measurement, the Shinwa® ruler presents acceptable reliability but requires the purchase of equipment. The reliability of ImageJ® software is the best and appears to be the most reliable method. Our original study, with no equivalent in the scientific literature, demonstrates objectively the great accuracy and reliability of a method of measurement of vascular calibers in micro and super microsurgery using intraoperative photography and the use of free computer software.