Final answer:
Removal of feces and flatus through a colostomy is often the result of natural peristaltic movements and bacterial activity in the colon, but the Valsalva's maneuver may be used to assist when necessary. Surgical interventions like a fecal pouch or ileostomy might be required for some conditions.
Step-by-step explanation:
The technique used to remove feces and flatus from the bowel through a colostomy is typically not a manual process, but rather a result of the normal functioning of the intestinal flora and peristaltic movements. In cases where assistance is needed, individuals might use a process similar to the Valvsalva's maneuver, where they voluntarily increase intra-abdominal pressure to facilitate the removal of waste. This is done by contracting the diaphragm and abdominal wall muscles and closing the glottis. In some situations, a more direct intervention, such as irrigation, may be used to clean the colon through the colostomy.
Additionally, there are surgical techniques such as the construction of a fecal pouch or an ileo- or colostomy for those who require an alternative way for eliminating digestive waste due to various medical conditions. The residue of chyme that enters the large intestine contains little nutrients, and after the extraction of water, the feces are moved towards the rectum by peristaltic movements and ultimately eliminated. In the case of a colostomy, the feces will exit through a surgically created opening in the abdomen instead of the rectum.