Crohn's disease IBD IBS Medicine anti-TNF bio-naïve biologic therapy biologic treatment chronic intestinal pseudo-obstruction colorectal motility combination inflammatory bowel disease inflammatory bowel diseases lymphocyte migration microbiota myopathy neuropathy parenteral nutrition pediatrics postoperative complications preoperative therapy pro-inflammatory cytokines surgery treatment ulcerative colitis ustekinumab vedolizumab visceral hypersensitivity