The reliability of cecal landmarks during colonoscopy.

Confirming colonoscopic intubation of the cecum can be a laborious, time-consuming, and often frustrating endeavor. Anatomic landmarks may offer visual clues of cecal intubation, but the predictability of this evidence is unclear. The presence of three cecal landmarks, alone and in combination, were evaluated to precisely define their reliability. Between February and October of 1991, 601 of 708 (85%) consecutive colonoscopic examinations were able to be completed to the cecum as confirmed by fluoroscopy. All three cecal landmarks studied were present in 64% (386/601), two cecal landmarks in 32% (189/601), and one cecal landmark in 4% (26/601) of the patients. Therefore, at least two cecal landmarks were identified in 96% (575/601) of the patients. The ileocecal sphincter was identified in 98% (591/601) of patients overall, in 98% (185/189) of patients and 2 cecal landmarks, and in 77% (20/26) of patients with 1 cecal landmark. The appendiceal orifice was seen in 87% (524/601) of patients overall and in 72% (137/189) of patients with 2 cecal landmarks. Transillumination through the abdominal wall was possible in 74% (447/601) of patients overall and in 30% (56/189) of patients with 2 cecal landmarks. In summary, the ileocecal sphincter is the most reliable cecal landmark and is invariably visualized, even when all other landmarks are obscure. While other cecal landmarks, such as the appendiceal orifice and transillumination, are consistently identified, they are most valuable when found in association with the ileocecal sphincter.