Diverticulitis: Inflammation of a DIVERTICULUM or diverticula.Diverticulitis, Colonic: Inflammation of the COLONIC DIVERTICULA, generally with abscess formation and subsequent perforation.Colon, Sigmoid: A segment of the COLON between the RECTUM and the descending colon.Sigmoid Diseases: Pathological processes in the SIGMOID COLON region of the large intestine (INTESTINE, LARGE).Diverticulum, Colon: A pouch or sac opening from the COLON.Intestinal Perforation: Opening or penetration through the wall of the INTESTINES.Diverticulosis, Colonic: A pathological condition characterized by the presence of a number of COLONIC DIVERTICULA in the COLON. Its pathogenesis is multifactorial, including colon aging, motor dysfunction, increases in intraluminal pressure, and lack of dietary fibers.Diverticulum: A pouch or sac developed from a tubular or saccular organ, such as the GASTROINTESTINAL TRACT.Colectomy: Excision of a portion of the colon or of the whole colon. (Dorland, 28th ed)Colonic Diseases: Pathological processes in the COLON region of the large intestine (INTESTINE, LARGE).Jejunal Diseases: Pathological development in the JEJUNUM region of the SMALL INTESTINE.Colostomy: The surgical construction of an opening between the colon and the surface of the body.Urinary Bladder Fistula: An abnormal passage in the URINARY BLADDER or between the bladder and any surrounding organ.Barium Sulfate: A compound used as an x-ray contrast medium that occurs in nature as the mineral barite. It is also used in various manufacturing applications and mixed into heavy concrete to serve as a radiation shield.Appendicitis: Acute inflammation of the APPENDIX. Acute appendicitis is classified as simple, gangrenous, or perforated.Enema: A solution or compound that is introduced into the RECTUM with the purpose of cleansing the COLON or for diagnostic procedures.Intestinal Fistula: An abnormal anatomical passage between the INTESTINE, and another segment of the intestine or other organs. External intestinal fistula is connected to the SKIN (enterocutaneous fistula). Internal intestinal fistula can be connected to a number of organs, such as STOMACH (gastrocolic fistula), the BILIARY TRACT (cholecystoduodenal fistula), or the URINARY BLADDER of the URINARY TRACT (colovesical fistula). Risk factors include inflammatory processes, cancer, radiation treatment, and surgical misadventures (MEDICAL ERRORS).Digestive System Surgical Procedures: Surgery performed on the digestive system or its parts.Surgical Procedures, Elective: Surgery which could be postponed or not done at all without danger to the patient. Elective surgery includes procedures to correct non-life-threatening medical problems as well as to alleviate conditions causing psychological stress or other potential risk to patients, e.g., cosmetic or contraceptive surgery.Anastomosis, Surgical: Surgical union or shunt between ducts, tubes or vessels. It may be end-to-end, end-to-side, side-to-end, or side-to-side.Appendix: A worm-like blind tube extension from the CECUM.Watchful Waiting: Clinical management approach wherein immediate therapy is not provided but there is a period of observation during which periodic tests monitor patient and the progression of the illness. (Driffield T, Smith PC Med Decis Making. 2007 Mar-Apr;27(2):178-88)Meckel Diverticulum: A congenital abnormality characterized by the outpouching or sac formation in the ILEUM. It is a remnant of the embryonic YOLK SAC in which the VITELLINE DUCT failed to close.Peritonitis: INFLAMMATION of the PERITONEUM lining the ABDOMINAL CAVITY as the result of infectious, autoimmune, or chemical processes. Primary peritonitis is due to infection of the PERITONEAL CAVITY via hematogenous or lymphatic spread and without intra-abdominal source. Secondary peritonitis arises from the ABDOMINAL CAVITY itself through RUPTURE or ABSCESS of intra-abdominal organs.Pneumoperitoneum: A condition with trapped gas or air in the PERITONEAL CAVITY, usually secondary to perforation of the internal organs such as the LUNG and the GASTROINTESTINAL TRACT, or to recent surgery. Pneumoperitoneum may be purposely introduced to aid radiological examination.Laparoscopy: A procedure in which a laparoscope (LAPAROSCOPES) is inserted through a small incision near the navel to examine the abdominal and pelvic organs in the PERITONEAL CAVITY. If appropriate, biopsy or surgery can be performed during laparoscopy.Peritoneal Lavage: Washing out of the peritoneal cavity. The procedure is a diagnostic as well as a therapeutic technique following abdominal trauma or inflammation.Cecal Diseases: Pathological developments in the CECUM.Intestinal Obstruction: Any impairment, arrest, or reversal of the normal flow of INTESTINAL CONTENTS toward the ANAL CANAL.Abdominal Pain: Sensation of discomfort, distress, or agony in the abdominal region.Abdomen, Acute: A clinical syndrome with acute abdominal pain that is severe, localized, and rapid in onset. Acute abdomen may be caused by a variety of disorders, injuries, or diseases.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Colonoscopy: Endoscopic examination, therapy or surgery of the luminal surface of the colon.Gastrointestinal Hemorrhage: Bleeding in any segment of the GASTROINTESTINAL TRACT from ESOPHAGUS to RECTUM.Acute Disease: Disease having a short and relatively severe course.Abdominal Abscess: An abscess located in the abdominal cavity, i.e., the cavity between the diaphragm above and the pelvis below. (From Dorland, 27th ed)Colon: The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON.Anastomotic Leak: Breakdown of the connection and subsequent leakage of effluent (fluids, secretions, air) from a SURGICAL ANASTOMOSIS of the digestive, respiratory, genitourinary, and cardiovascular systems. Most common leakages are from the breakdown of suture lines in gastrointestinal or bowel anastomosis.Recurrence: The return of a sign, symptom, or disease after a remission.Therapeutic Irrigation: The washing of a body cavity or surface by flowing water or solution for therapy or diagnosis.Laparotomy: Incision into the side of the abdomen between the ribs and pelvis.Fistula: Abnormal communication most commonly seen between two internal organs, or between an internal organ and the surface of the body.Foreign-Body Reaction: Chronic inflammation and granuloma formation around irritating foreign bodies.