How to Size the Anal Canal Circumference When Implanting a Magnetic Anal Sphincter for Fecal Incontinence. Evolution and Update of a New Surgical Technique.

Abstract

Magnetic anal sphincter augmentation improves function and quality of life of patients with severe fecal incontinence substantially. Measuring the anal circumference exactly with a sizing tool represents a crucial step of the procedure because it determines the correct size and success of the definite implant. This study aims to illustrate the consequent development of 3 different sizing models and the use of the recent sizing tool. After dissection of a tunnel around the anal canal through a ventral perineal incision, the sizing tool is inserted by using a specially designed introducer to measure the circumference for the appropriate size of implant. First- and second-generation sizing tools could only approximate the final implant size and impeded standardization. The latest sizing model resembles the actual implant with magnetic beads, it is nonstretchable, and it is closable end-to-end. The development of 3 measuring tools has progressively improved the accuracy of estimating the correct size of the definitive implant, and the application of the latest sizer seems easy, comfortable in use, and accurate as experienced in our first cases. The latest device contributes to standardization of the procedure and therefore facilitates the learning curve for newcomers of the method and could avoid the need for radiological on-table control in the near future.