The one piece colostomy bag system does not require assembly of the wafer, also known as the skin barrier and colostomy bag. It is a system that is attached directly to the skin. This type of system can be used with an open or closed ended bag. However, when the bag needs to be changed, the entire system has to be removed from the skin. Because this system does not need any assembly, it may be ideal for patients who have hand problems, such as arthritis.
The two piece colostomy bag system is made of the skin barrier and the bag--which could be closed or open ended. To use this system, the skin barrier is applied first and then the bag is attached to it. The advantage of this system is that it can be used with different types of bags because the bag can be removed and changed. A small bag could be worn for activities like swimming and a closed ended bag could be used to facilitate disposal of the colostomy bag after one use only. Also, to change bags, the entire system does not have to be removed. Instead, the wafer is left on the skin while the bag is replaced.