Incomplete flexible sigmoidoscopy insertion after cesarean section.

Cesarean section (C/S) is one of the most commonly undertaken operations e no fewer than 18.5 million C/S are annually performed worldwide. However, the high rate of C/S births has become a global public health concern. Taiwan has one of the highest rates of C/S births, comprising approximately 33% of all births over the last 10 years. In this issue, a team of investigators from Kaohsiung Veterans General Hospital tried to identify the risk factors of incomplete flexible sigmoidoscopy. They found that only prior pelvic surgery was an independent risk factor for incomplete flexible sigmoidoscopy insertions, with a high odds ratio (OR) of 3.54, based on the fact that both C/S and hysterectomy were main components of the prior surgery. They concluded that both hysterectomy and C/S, individually, can predict incomplete flexible sigmoidoscopy among individuals with prior abdominal or pelvic surgery. We congratulate the authors for their successful work, which has been published in this issue. However, are their conclusions realities or only a myth? Some questions and issues require our attention. First, in terms of the role of C/S in the current study, no statistically significant difference was noted between incomplete insertion and complete insertion (24% vs. 25%, p 1⁄4 1.00). We wonder why the authors would conclude that C/S contributed to one of the two main causes of incomplete flexible sigmoidoscopy insertions. A possible reason was that there were too many C/S patients (n 1⁄4 26). However, by enrolling these women with a history of C/S, the significantly unbalanced sex distribution that resulted might have led to a palpable selection bias (male vs. female, 39% vs. 61%). One study found that female sex was significantly related to a limited flexible sigmoidoscopy examination [OR 1⁄4 1.83, 95% confidence interval (CI) 1⁄4 1.60e2.10], and female sex predicting a limited examination was more powerful than was previous pelvic or abdominal surgery (OR 1⁄4 1.29, 95% CI 1⁄4 1.12e1.49). C/S was assumed to be a predictor of incomplete flexible sigmoidoscopy insertion in the current study. This observation might be biased, and it would have been better not to enroll women with a previous C/S in the current study. After excluding those patients with previous C/S, a revised total of 80 patients would be more appropriate study representatives, because of the improved sex distribution (male vs. female, 51% vs. 49%). In addition, the results might be more convincing, and less prone to second guessing.