Safe and Painless Insertion in Colonoscopy

Background and Aims: Colonoscopy is a superior tool for detection, diagnosis and treatment of colorectal neoplasia. However, it is frequently difficult to insert the colonoscopy because of a long colon, diverticular disease, or history of abdominal surgery. When the colonoscope is not inserted straightly in passing through rectosigmoid (RS) or sigmoid-descending colon (S-D) junction, patients often have abdominal pain. The aim of this prospective study is to assess the relationships between the passage patterns and presence of pain, insertion time from anal verge to cecum, the history of abdominal surgery, presence of diverticular disease, age, body mass index (BMI), or gender. Materials and Methods: Two colonoscopists with extensive experience performed total colonoscopy in 329 patients without complaint of abdominal pain at Showa University Hospital from April 2005 through November 2005. The passage patterns in colonoscopic insertion were defined according to whether loops are formed in passing through the RS or S-D junction. We classified passing pattern into push insertion pattern which made loops such as N-loop, alpha-loop or double loop to pass through RS or S-D junction and straight insertion pattern which passed up the S-D junction within scope length of approximately 30 cm as a result of making no loops. Results: The straight insertion pattern and push insertion pattern were found in 214 patients (65%) and 115 patients (35%), respectively. The frequency of painlessness was significantly higher in straight insertion group (205 of 214: 96%) than in push insertion group (47 of 115: 41%, p < 0.0001). The mean insertion time from anal verge to cecum was significantly shorter in straight insertion group (4.9 ± 2.4 minutes) than in push insertion group (11.2 ± 5.2 minutes, p < 0.0001). The frequency of history of abdominal surgery was significantly higher in push insertion group (45 of 115: 39%) than in straight insertion group (60 of 214: 28%, p = 0.04). The frequency of female gender was significantly higher in push insertion group (54 of 115; 47%) than in straight insertion group (68 of 214: 32%, p = 0.006). No significant differences were seen in age, BMI and the presence of diverticular disease between push and straight insertion groups. We observed no serious complication during or immediately after colonoscopy in all patients. Conclusions: It is important for safe and painless colonoscopy to prevent loop formation and to keep the scope axis straight in the RS and S-D junction. Colonoscopists should pay attention to female patients or patients with history of abdominal surgery.