Abstract Aim: To compare the effectiveness and safety of laparoscopic and conventional “open” appendectomy in the treatment of acute appendicitis. Methods: Meta-analy- sis of randomised controlled trials available by May 1998 that compared both techniques. Within each trial and for each outcome an effect size was calculated; the effect sizes were then pooled by a random-effects model. Results: We summarised outcome data of 2877 patients included in 28 trials. Operating time was +16 min (95% confidence inter- val +12–20 min) longer for laparoscopic appendectomy. Overall complication rates were comparable, but wound infections were definitely reduced after laparoscopy [rate difference –4.2%, (–2.3% to –6.1%)]. Intra-abdominal abscesses, however, occurred slightly more frequently [+0.9%, (–0.4% to +2.3%)]. Hospital stay after laparos- copic appendectomy was 15 h (8–23 h) shorter, and pa- tients returned to full fitness or work 7 days (5–9 days) earlier. Pain intensity on day 1 was slightly less. Hetero- geneity was present for some outcome measures due to methodological differences among the primary studies. Conclusion: Laparoscopic appendectomy reduces wound infections and eases postoperative recovery. Nevertheless, the various differences among the primary studies and their partly flawed methodology make it difficult to generalise from these findings. Key words Appendectomy · Laparoscopy · Meta-analysis · Randomized controlled trials Introduction Since its introduction by McBurney in 1894, appendec- tomy is the treatment of choice for acute appendicitis [1]. It soon became one of the most frequently performed sur- gical procedures. Today, in developed countries, about 8% of the population is appendectomised for acute appendi- citis at some point during their lifetime [2]. The surgical technique remained mostly unchanged for over a century, as it combined therapeutic efficacy with low morbidity and mortality rates [3]. The evolution of endoscopic surgery led to the idea of performing appendectomy via laparos- copy; this was first described by Semm in 1983 [4]. Nev- ertheless, the new method has only gained partial accep- tance, because the advantages of laparoscopic appendec- tomy are not as obvious as for laparoscopic cholecystec- tomy. For example, while some studies claimed laparos- copic appendectomy to be superior to open appendectomy in terms of a quicker and less painful recovery, less post- operative complications, and better cosmesis, other stud- ies either found no such advantages or even favoured the traditional approach. The randomised controlled trial is generally considered the most reliable method of assessing the efficacy of dif- ferent treatment options. For the comparison of surgical procedures, randomised trials are difficult to conduct, be- cause of patients’ or physicians’ preferences for one ther- apy, the learning-curve bias of the surgeon performing the new procedure, and the difficulties in blinding patients and investigators when assessing outcome measures [5]. This resulted in a methodologically inferior and delayed evalu- ation of laparoscopic appendectomy. However, the large number of high-quality trials published now and the still- ongoing debate has prompted us to undertake a meta-anal- ysis of all randomised trials that have compared both tech- niques. Langenbeck’s Arch Surg (1998) 383: 289–295 © Springer-Verlag 1998 Received: 25 May 1998 Stefan Sauerland · Rolf Lefering · Ulla Holthausen Edmund A. M. Neugebauer Laparoscopic vs conventional appendectomy – a meta-analysis of randomised controlled trials EVIDENCE-BASED SURGERY An earlier version of this paper was presented as a poster at the 115th Congress of the German Society for Surgery, Berlin, 28 April–2 May 1998 S. Sauerland · R. Lefering · E. A. M. Neugebauer () Biochemical and Experimental Division, 2nd Department of Surgery, University of Cologne, Ostmerheimer Str. 200, D-51109 Cologne, Germany Tel.: +49 221 989570; Fax: +49 221 893864; e-mail: k.nasskau@uni-koeln.de U. Holthausen Surgical Clinic, 2nd Department of Surgery, University of Cologne, Cologne, Germany