Two-finger digital rectal examination for the diagnosis of anal fistula: protocol for a randomized controlled trial.

Background: Anal fistula is an anorectal infectious disease caused by a perianal abscess or perianal disease. Accurate anorectal examinations are of great significance. The two-finger digital rectal examination (TF-DRE) has been used in clinical practice, with a lack of comprehensive research on the value of the TF-DRE in the diagnosis of anal fistula. This study will compare the difference in the diagnostic value of the TF-DRE, traditional digital rectal examination (DRE), and anorectal ultrasonography in the diagnosis of anal fistula.

Methods: For patients who meet the inclusion criteria, a TF-DRE will be performed to explore the number and location of the external and internal orifices, the number of fistulas, and the relationship between the fistula and the perianal sphincter. A DRE and anorectal ultrasonography will also be performed, and the same data will be recorded. To make a comparison, the final diagnosis results of the clinicians during the operation will be taken as the gold standard, the accuracy of the TF-DRE in diagnosing anal fistula will be calculated, and the significance of the TF-DRE in the preoperative diagnosis of anal fistula will be studied and analyzed. All the statistical results will be analyzed using SPSS22.0 (IBM, USA), and a P value <0.05 will be considered statistically significant.

Discussion: The research protocol details the advantages of the TF-DRE compared to the DRE and anorectal ultrasonography in the diagnosis of anal fistula. This study will provide clinical evidence of the diagnostic value of the TF-DRE in the diagnosis of anal fistula. Currently, there is a lack of high-quality research using scientific methods on this innovative anorectal examination method. This study will provide rigorously designed clinical evidence on the TF-DRE.

Registration: Chinese Clinical Trials Registry ChiCTR2100045450.