ObjectiveTo evaluate the value of the Goodsall rule in predicting internal opening of anal fistula and the value in locating the internal opening of anal fistula using biplane transrectal ultrasonog raphy.

MethodsThe clinical data of 52 patients(70 anal fistulas) who underwent surgical treatment were retrospectively analyzed.The internal opening of anal fistula of each patient was predicted according to the Goodsall rule before surgery, and the internal fistula was simultaneously explored by biplane transrectal ultrasonography.Both results were compared with surgical exploration results via a consistency test.

ResultsThe consistency rate of the Goodsall rule and operation diagnosis was 87.1%, and the Kappa value in the consistency test was 0.657, showing strong consistency(P < 0.01).The consistency rate of ultrasonic exploration and surgical diagnosis was 88.6%, and the Kappa value in the consistency test was 0.676, showing strong consistency(P < 0.01).Results of ultrasonic exploration of 70 anal fistulas were listed as follows: 12 superficial subcutaneous fistulas, 43 intersphincteric fistulas, 10 transsphincteric fistulas, 2 superior sphincteric fistulas and 3 horseshoe fistulas.The Goodsall rule had a high coincidence with ultrasonic exploration for superficial subcutaneous, intersphincteric anal fistulas and ultrasonic probe(90.1%).However, the prediction rate of the Goodsall rule for the internal opening of transsphincter type, horseshoe type, and suprasphincter type was not high(46.9%), and the Kappa value of consistency test was 0.486, showing moderate consistency(P < 0.05).

ConclusionsThe value of the Goodsall rule in predicting the internal opening is highly consistent with surgery or biplane transrectal ultrasonography, showing a certain clinical value, especially for superficial subcutaneous fistula and intersphincteric anal fistulas, whereas there are some limitations in predicting the location of fistulas in front of the transverse line and the internal opening of horseshoe, transsphincter, and suprachincter fistulas.In ultrasound examination and clinical treatment, the Goodsall rule can be effectively combined with biplane transrectal ultrasonography to improve the diagnosis and treatment effect.