Original researchPopulation level analysis of diagnostic laparoscopy versus normal appendicectomy for acute lower abdominal pain

- Evidence surrounding removal of a macroscopically normal appendix at laparoscopy is single-centred and small numbered.
- Current international practice is fragmented, where two-thirds of surgeons remove the appendix and one-third leave it.
- Planning a randomised trial without data to inform design and sample size is not possible.
- Removing a normal appendix was associated with reduced emergency readmission for abdominal pain at one year.
- This study provides guidance for power calculations for an international randomised trial.

Background: There is virtually no evidence to guide surgeons and patients when faced with an absence of pathology for acute lower abdominal pain. This study aimed to compare diagnostic laparoscopy alone to laparoscopic removal of a normal appendix in patients with acute lower abdominal pain but an absence of pathology. Method: Retrospective analysis of routinely collected hospital data from all English acute hospitals performing emergency appendicectomy between 01/04/2002 and 31/03/2012. Patients admitted as emergencies with lower abdominal pain undergoing diagnostic laparoscopy (with no other procedure or associated diagnosis) were compared to those undergoing laparoscopic normal appendicectomy. The primary outcome measure was emergency readmission for abdominal pain during the 12 period after index surgery. Multivariable binary logistic regression was used to produce adjusted odds ratios (OR and bootstrapped 95% confidence intervals). Result: 10,072 patients undergoing diagnostic laparoscopy were compared to 9665 undergoing laparoscopic normal appendicectomy. Overall, 32.9% (n = 6499/19,737) were readmitted as an emergency for abdominal pain during the 12 months after index surgery. Following risk-adjustment, laparoscopic normal appendicectomy was associated with 44% reduced odds of readmission (adjusted OR 0.56, 0.50-61). In the diagnostic laparoscopy group, 2.1% of patients (213) required subsequent appendicectomy, which was abnormal in 47.4% (101/213) cases. Conclusion: This study suggests that removal of a laparoscopically normal appendix, when no other pelvic pathology is visible, may reduce one-year readmission rates. Although limited through selection bias from routinely collected data, this study provides evidence for practicing surgeons and information for methodologists to power a future trial.