3.1. Search results and study characteristics
The systematic literature review from 1981 to 2019 provided the following results: 581 reports and, after duplicates removal, 261 were screened. After screening of titles and abstract, 92 papers were excluded. The full texts of the remaining 169 articles were evaluated, and 137 studies were excluded with reasons. A total of 32 articles (observational studies and case series, no randomized controlled trial), including 1191 patients, were enrolled [29-60]. A PRISMA flow diagram of the study selection process can be found in Figure 1. The quality assessment of the included studies is reported in Supplementary Tables 2-5. Pooled patient data are presented in Table 1. All studies, patients’ characteristics, main surgical strategies and early outcome results were summarized in Table 2.