Letter to the Editor, Reply to “Commentary on Meta-analysis of Prospective Randomized Studies Comparing Single-Incision Laparoscopic Cholecystectomy (SILC) and Conventional Multiport Laparoscopic Cholecystectomy (CMLC)” by Pisanu et al. (J Gastrointest Surg 2012; 16:1790–1801)

Abstract

Sir, Thank you very much to Dr. Christensen for the interest in our meta-analysis comparing the outcomes of single-incision laparoscopic cholecystectomy (SILC) and conventional multiport laparoscopic cholecystectomy (CMLC), which has been published in the Journal of Gastrointestinal Surgery in July 2012. For the aim of this meta-analysis, variables were considered only if evaluated by three or more studies in order to reduce the occurrence of a type II error related to the small number of cases, as data could also be combined from only two studies. All outcomes of interest were tested for heterogeneity and adjusted for small sample bias. Those studies that not reported data about the outcomes of interest were excluded from the meta-analysis. The case of major biliary injury after SILC cholecystectomy, however, is a different matter. As you surely noticed, data about major biliary injury have not been summarized in a forest plot because, fortunately, no cases of this feared complication occurred in the included trials. Thus, the impossibility to meta-analyze data about major biliary injury was related to the absence of this complication rather than to the small number of pooled patients or to the unreported data. The absence of major biliary injury in cholecystectomies performed in the setting of randomized studies and in specialized centers must not create a false sense of security in the community of surgeons until the processes of SILC standardization will be completed. The uncontrolled diffusion of SILC has been considered as responsible for an increased number of bile duct injuries that have been reported with prevalence as high as 0.7 %, which is an unacceptable complication rate. Our pooled analysis included 12 clinical trials for a total of 892 patients randomized for both SILC and CMLC techniques. At the time of the survey, these were the best possible summarized results from the literature. We are aware that this is not enough to consider the processes of SILC standardization as completed. Indeed, we concluded that SILC cholecystectomy is a safe and effective procedure for the treatment of uncomplicated benign gallbladder disease andmay be proposed as an alternative for cholecystectomy in “properly selected patients and in experienced hands.” The need for new larger prospective multicenter studies to better assess the SILC technique has also been advocated at the end of our paper. The overall morbidity rate was higher in the SILC group (13.1 vs. 9.8 %), and it was mainly represented by the surgical site infection and postoperative incisional hernia at the umbilical site. This difference did not reach statistically significant difference. Meta-analysis increases the statistical power of the outcomes by pooling data from several studies, as the size of individual clinical trial is often too small to detect outcome consistency. In the case of overall morbidity, there was no heterogeneity among the included trials and the weighted summary OR 1.16 was calculated under the fixed effects model. This means that all included trials were homogeneous with regard to the assessment of overall morbidity, and if all studies were infinitely large, they would yield identical estimate of the effect. The too short follow-up suggests approaching the result A. Pisanu : I. Reccia :G. Porceddu :A. Uccheddu Department of Surgery, Clinica Chirurgica, University of Cagliari, Monserrato, Italy