Received: 14 June 2021
Accepted: 30 August 2021
First Online: 7 September 2021
: The authors declare that they have no conflict of interest.
: The study was approved by Keio university’s ethics committee (20150051).
: All patients signed the institution informed consent for colorectal surgery. No specific consent for this type of study is required.
: Consent to submit the present paper has been received explicitly from all co-authors, as well as from Keio university’s ethics committee.
: This article does not contain any studies with animals performed by any of the authors.