I Have Been Told I Need An Ileorectal Anastomosis For

I have been told I need an ileorectal anastomosis for slow transit constipation; the nerves in my large intestine are non-functional, and I have to rely on painful laxative medications in order for my bowels to move. How successful is IRA for slow transit syndrome, and will I have to wear some kind of colonostomy bag? I look forward to your response.
Kind regards,
Susan