Abstract: Objective To explore the application value of endoscope in probing the chronic wound with sinus tract in clinic. Methods Twenty-eight chronic wounds with sinus tracts from 27 patients conforming to the inclusion criteria admitted to Outpatient Department of Wound Healing Center of Ruijin Hospital from December 2017 to March 2018 were investigated in a prospective and self-controlled trial. After being cleaned, the diameter of the opening of sinus tract was measured with a rule. A probe was used to measure the depth of a sinus tract according to the touch from the probe extremity in operation, and to measure the depth of a sinus tract that could be observed with naked eyes with the help of a pair of hemostatic forceps. Five minutes later, a probe was inserted deeply into the sinus tract to measure the depth under the endoscopic view combined with touch from the probe extremity in operation. Afterwards, the sinus tract was observed with endoscope, and the depth of the tract which could be observed under the endoscopic view was measured using a probe inserted deeply into the sinus tract. After completion of the above exploration, the sinus tract was infused with contrast agent Omnipaque 350 and scanned by computed tomography (CT) later to obtain its depth. The following indicators were calculated: the ratio of the depth of the sinus tract measured by CT to the diameter of the opening of the sinus tract (hereinafter referred to as the depth/diameter ratio of the sinus tract), the deviation rate comparing the depth of the sinus tract measured by conventional method (measured by probe only) and by endoscope (measured by probe under the endoscope view) with the depth of the sinus tract measured by CT (hereinafter referred to as the deviation rate of the measured depth of the sinus tract), the deviation rate comparing the depth of the sinus tract that could be observed measured by conventional method and by endoscope with the depth of the sinus tract measured by CT (hereinafter referred to as the deviation rate of the depth of the sinus tract that could be observed). Data were processed with paired t test. Pearson correlation analysis was applied to analyze the correlation between the depth/diameter ratio of the sinus tract and the deviation rate of the measured depth of the sinus tract and the deviation rate of the depth of the sinus tract that could be observed by conventional method and by endoscope. Results The depth/diameter ratio of the sinus tract of this group of wounds was 1-32 (8±7). The deviation rate of the measured depth of the sinus tract and the deviation rate of the depth of the sinus tract that could be observed by conventional method were (19±14)% and (79±18)%, respectively, both obviously larger than (9±9)% and (25±25)% by endoscope (t=3.837, 13.626, P<0.01). Positive correlation existed between the depth/diameter ratio of the sinus tract and the deviation rate of the measured depth of the sinus tract by conventional method, and between the depth/diameter ratio of the sinus tract and the deviation rate of the depth of the sinus tract that could be observed by conventional method and by endoscope (r=0.514, 0.585, 0.651, P<0.01). However, there was no obvious correlation between the depth/diameter ratio of the sinus tract and the deviation rate of the measured depth of the sinus tract by endoscope (r=0.113, P>0.05). Conclusions Compared with the conventional method, application of endoscope is able to get more accurate data of chronic wounds with sinus tracts and observe the wounds with wider range.