Rules for anal fistulas with scrotal extension

Abstract

Abstract:Objectives: To evaluate the rules for anal fistulas with scrotal extension, in particular, whether a high transsphincteric or suprasphincteric fistula, of which internal openings are usually located posteriorly, would extend into the scrotum. Methods: We retrospectively analyzed 446 consecutive male patients who underwent definitive anal fistula surgery. We compared fistulas with scrotal extension according to the location of the internal opening and divided them into anterior and posterior groups. Results: Forty-six (82.1%) of the 56 anal fistulas with scrotal extension had anterior internal openings. After excluding recurrent fistulas, 42 (87.5%) of the 48 anal fistulas with scrotal extension had anterior internal openings. The relative risk of scrotal extension in the anterior group was 14.22 times higher than that in the posterior group (95% CI: 7.43-27.21; p<0.0001). After excluding recurrent fistulas, this relative risk rose to 18.67 (95% CI: 8.18-42.58), (p<0.0001). Conclusions: Anal fistulas with scrotal extension are mostly low transsphincteric or intersphincteric with anterior internal openings. High transsphincteric or suprasphincteric fistulas rarely extend into the scrotum, except in recurrent cases.

Preoperative magnetic resonance imaging of anal fistulas with scrotal extension

“…We observed a signi cant correlation between the location of internal opening (anterior or posterior to the transverse anal line) and the stula type (p < 0.05). This is consistent with the previous reported [7,18] which showed that the majority of anal stulas extending into the scrotum were low transsphincteric stulas with the anterior internal opening. Also, high transsphincteric and suprasphincteric stulas usually had posterior internal openings.…”

“…Goodsall's rule for predicting the trajectory of anal stulas is popular; however, the long-tract anterior stula, which may include stulas with scrotal extension, is an exception to this rule [7]. Magnetic resonance (MR) is extremely useful in these cases thanks to its capability to provide precise anal canal anatomy and the relation of the stula to perineal structures.…”

Long anterior anal fistula with an external opening in the medial raphe of the scrotum is likely to open radially inside the anal canal: an addition to the Goodsall’s rule

“…The authors conjectured that all exceptions of the GR, wherein a long anterior fistula opening anteriorly will possibly be of a low variety, either intersphincteric or trans-sphincteric. In their series, there was no case of long anterior high suprasphincteric fistulas with anterior internal openings 1. Taken together, the above shows that anal fistulas opening in the midline raphe of the scrotum are rarely reported, are primarily of the low variety with no suprasphincteric extensions and open anteriorly in the anal canal.…”

“…Goodsall’s rule (GR) states that if the external opening of an anal fistula is anterior to a transverse line across the anus will open radially into the anterior wall of the anal canal provided it is less than 3 cm from the anal verge, else it will open in the midline posteriorly 1. Exceptions to this rule have been reported for long anterior fistulas which instead of opening posteriorly in the midline as per the GR, opens anteriorly 2.…”

Analysis of Deep Posterior Anal Fistulas by Magnetic Resonance Imaging: Site of Primary Abscess and Extension Patterns According to the Primary Abscess Depth

“…The drainage seton band was removed 4-6 weeks after the operation. Healing of the anal fistula was confirmed when the wound was completely epithelialized, with no fluid collection apparent on MRI after the fistula was transected and the seton removed 8) . We named these procedures "MRI navigating seton" surgery.…”