As Rock said, you need a diagnosis. To see if your colon is the problem (colonic inertia means your colon does not work) you have to do a sitzmark test. That means you swallow a pill with tiny markers in it and every few days you get an xray to see how fast (or how slow) they are going through your small intestine and your colon. If they end up all spread out and not moving too fast in your colon, then you have a colon that does not work well.
If the markers are all down near your rectum, I think it means your constipation issue is called outlet obstruction, meaning poop travels along OK through your colon, but then cannot get out. Either way, you need to find out.
Keep asking. You need a lot of tests. If anyone want to operate without sitzmark test, defecogram, pudental nerve test, and anorectal manometry and balloon expulsion test, then you are not dealing with the right doc. Those are the tests you need. You need to move on this as you have been suffering for a really long time. Any surgery can create an adhesion. BUT if done laporoscopically especially with a spray adhesion barrier, then you will likely not be bothered by adhesions. Plus, you can get adhesions that are asymptomatic. That means they do not cause pain or obstruction. Usually a first and only surgery will not give you bothersome type adhesions as long as the surgery is done well and not super extensive. Good luck, Rosemary