Can you get a mandible implant to make the jaw wider without it lowering the ramus/angle of the mandible?

Jaw angle implants come in several shapes and sizes.  Most of them that widen the jaw on front view significantly would lower the jaw at the angle a couple of millimeters (this is subtle)...you probably won't notice.  If you literally want zero ramus lowering you could talk to your surgeon and they might be willing to modify the implant to remove the part that lowers the ramus.  This part you would want removed helps stabilize the implant in the right location and helps ensure symmetry and so you may want to ask your surgeon if they do modify the implant are they going to put a screw or extra screws in to hold the implant in place, and do they think there is a higher chance of asymmetry if the implant(s) are modified.  Best of luck!

Jaw angle implants or custom implants can be placed top enhance the jaw angle and not lengthen the mandible.  These implants are made from silicone or medpore.  

Some types of standard jaw angle implants only make the jaw angle wider not longer. Or they can be custom designed for that effect if for some reason standard implants will not work in your case.