Fecal Matter in Colon

I had my thyroid removed last August and immedately became constipated, however still  had the urge to go. In march I had a hystercomy and have not had the urge to go to the bathroom since. I recently had an upper GI and it showed large amount of fecal matter in my colon most likely due to constipation. I have tried Fleet, tea and Go lighlty and still have not had much a bowel movement. How do they remove the fecal matter if you can't do it through fiber or laxatives. I am afraid to have a colonic in case there is somthing else wrong.

Thank you for responding.