Which of the following statement(s) is/are true concerning the etiology of intestinal obstruction?

d. Ninety percent of adult cases of intussusception are associated with a pathologic process, most commonly a tumor

Peritoneal adhesions account for more than half of the cases of small bowel obstruction in the United States. Obstruction in the immediate postoperative period following abdominal surgery, however, is uncommon, occurring in only 1% of patients in the four weeks following laparotomy. Hernias of all types are second only to adhesions as the most frequent cause of obstruction. External hernias such as inguinal or femoral hernias may present with symptoms of obstruction. Femoral hernias are particularly prone to incarceration and bowel necrosis, due to the small size of the hernia inlet. One important consideration is the Richter’s hernia. In this variant, only a portion of the bowel wall is incarcerated. These most frequently occur in association with femoral or inguinal hernias. Complete obstruction can occur if more than half to two-thirds of the bowel circumference is incarcerated. About 5% of intussusception cases occur as adults. Intussusception occurs when one segment of bowel telescopes into an adjacent segment, resulting in obstruction and ischemic injury to the intussuscepting segment. Ninety percent of adult cases are associated with pathological processes. Tumors, benign and malignant, can act as a lead point against the sussesception in over 65% of adult cases.