Scroll click - Lock

I am a Radiologist and I often scroll through thousands of images for a single study. My preferred way to do this is a combination of scrolling and for the majority of the time, depressing the scroll wheel (programmed as scroll click) and just moving the mouse up and down the pad to scroll thru these vast number of images. After many years, my scroll finger that I use to constantly depress the scroll button for 9hrs is probably getting arthritic. Hyperscroll is not an option as I need to control very precisely the speed at which I move back and forth thru a set of images. What I NEED is for there to be a way to program buttons to LOCK the scroll click button, so I don’t have to be constantly pushing a button in. I have tried training other fingers to use as my scroll button and I have programmed every button on the mouse to have the same scroll click option. These are temporary solutions, to have other options. Does anyone know a way to have this the scroll click locked as an option. I have the Deathadder. Maybe another Razer mouse does this. I have asked Razer to add this as a new function request, but have not heard back from them. My tired 2nd finger thanks you for your help!