https://bmcsurg.biomedcentral.com/articles/10.1186/s12893-016-0174-x
https://bmcsurg.biomedcentral.com/articles/10.1186/s12893-016-0181-y
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https://bmcsurg.biomedcentral.com/articles/10.1186/s12893-016-0183-9
https://bmcsurg.biomedcentral.com/articles/10.1186/s12893-016-0182-x
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https://bmcsurg.biomedcentral.com/articles/10.1186/s12893-016-0184-8
https://bmcsurg.biomedcentral.com/articles/10.1186/s12893-016-0176-8
https://bmcsurg.biomedcentral.com/articles/10.1186/s12893-016-0179-5
https://bmcsurg.biomedcentral.com/articles/10.1186/s12893-016-0177-7