Patient characteristics
Nineteen cases of PSF in [removed for blind peer review] Prefecture in [removed for blind peer review] had been completely resected from 1997 to 2011 in the following six hospitals by a single chief surgeon (YY): [removed for blind peer review] University Hospital with 10 cases, [removed for blind peer review] Hospital with three cases, [removed for blind peer review] Hospital with two cases, [removed for blind peer review] Hospital with two cases, [removed for blind peer review] Hospital with one case, and [removed for blind peer review] Hospital with one case. The Institutional Review Board in [removed for blind peer review] University approved this study (No. 2017-196). Patient characteristics are summarized in Table 1. All fistulas were preoperatively detected by fluoroscopy and CT. Although some patient data were missing because this is a multicenter study, all cases, except one, were located on the left side. All cases were euthyroid and did not show high thyroglobulin level. One of the patients was in remission phase of acute megakaryoblastic leukemia.