2.1. Study selection

A Medline (PubMed), Embase, Ovid, CBM, and Cochrane database were used to perform the search for studies that compared the transperitoneal with extraperitoneal approach in LRP (including pure and robotic-assisted LRP) between 2000 and 2017. MeSH search headings used were: “laparoscopic,” “radical prostatectomy,” “robotic-assisted,” “extraperitoneal,” and “transperitoneal” and their combinations were also searched. The function of “related articles” was applied to enlarge the search. The references of each included study were also seriously reviewed. To ensure that any relevant studies were not missed, many scholars in the field of endourological surgery were consulted. This analysis included only comparative clinical full-text studies, and the final articles included in the study were agreed upon by all authors in this manuscript.