This article provides a detailed account of how surgeons perceived and used a device-procedure that caused widespread patient harm: transvaginal mesh for the treatment of pelvic floor disorders in women. Drawing from interviews with 27 surgeons in Canada, the UK, the United States and France and observations of major international medical conferences in North America and Europe between 2015 and 2018, we describe the commercially driven array of operative variations in the use of transvaginal mesh and show that surgeons' understanding of their hands-on, sensory experience with these variations is central to explaining patient harm. Surgeons often developed preferences for how to manage actual and anticipated dangers of transvaginal mesh procedures through embodied operative adjustments, but collectively the meaning of these preferences was fragmented, contested and deferred. We critically reflect on surgeons' understandings of their operative experience, including the view that such experience is not evidence. The harm in this case poses a challenge to some ways of thinking about uncertainty and errors in medical sociology, and calls for attention to a specific feature of surgical work: the extent and persistence of operative practices that elude classification as right or wrong but are still most certainly better and worse.