Should I use a left aligned scroll bar?

Usually, users expect scroll bars to be at the right side of the content they want to scroll. My page menu is located on the left side of the page however and is intended to be scrolled separately (navigations layout looks like roughly like this.

Can I risk putting my scroll bar left to the menu instead of right? It might make my page layout more balanced (one progress bar to the left, one to the right). I wonder if users would feel too unconfortable with it though so I went here.