kaylight, thank you so much for sharing your personal story with us, it is truly inspiring! You were indeed fortunate to find someone like Mia to help you.
While I personally use a closed system in my practice, I have received colonics from gravity flow open systems in the past and have posted here previously that you can achieve a good cleanse from either. I believe the most important factor that contributes to a successful cleanse is the skill, experience and motivation of the therapist.
You obviously found one with those attributes who spared you from the ordeal and dangers of surgery in bringing you back to good health.