Just to correct a typo in the first answer: the total number of nodes for a tree of depth L is (N^(L+1)-1) / (N-1)... (that is, to the power L+1 rather than just L). This can be shown as follows. First, take our theorem: 1 + N^1 + N^2 + ... + N^L = (N^(L+1)-1)/(N-1) Multiply both sides by (N-1): (N-1)(1 + N^1 + N^2 + ... + N^L) = N^(L+1)-1.
Malignancy is the most common cause of large bowel obstruction in older patients. Colon carcinoma without obstruction does not usually cause acute abdominal pain. Diverticulitis and colonic volvulus (i.e., narrowed, twisted lumen with a birdâs beak appearance) are less common causes of large bowel obstruction.4,5,14,35.
An interesting, yet rare, cause for small bowel obstruction in the elderly is gallstone ileus. This is caused by the passage of a large biliary calculus from the gallbladder to the distal iliem through a cholecystenteric fistula. This disorder carries an overall mortality rate of 15%.