Complex sentence: Surgery is usually recommended for most types of hernias in order to prevent complications like obstruction of the bowel or strangulation of the tissue, although umbilical hernias and hiatus hernias are usually left to heal on their own, or are treated with medication, respectively.
Split into simpler sentences: Surgery is usually recommended for most types of hernias in order to prevent complications like obstruction of the bowel or strangulation of the tissue. Although umbilical hernias and hiatus hernias are usually left to heal on their own, or are treated with medication, respectively.