High failure rates following ligation of the intersphincteric fistula tract for transsphincteric anal fistulas: are preoperative MRI measurements of the fistula tract predictive of outcome?

A controlled study of MR DWI, FS-PDW, and CE-T1W imaging for the evaluation of the internal opening of anal fistulas

BACKGROUND

Anal fistula (AF) is an abnormal tunnel under the skin connecting the anal canal in the colon to the skin of buttocks. Fat-suppressed (FS) proton density-weighted (PDW) imaging is mainly used for the diagnosis of diseases involving bones and joints. Until now, its value in the diagnosis of anal fistula has been rarely reported.

PURPOSE

To compare three magnetic resonance imaging (MRI) sequences - diffusion-weighted imaging (DWI), FS-PDW), and contrast-enhanced (CE) T1-weighted (T1W) imaging - for the diagnostic value of the internal opening of AF.

MATERIAL AND METHODS

MRI scans of 132 patients suspected of having AF between December 2021 and April 2023 were retrospectively analyzed. In total, 65 patients who underwent preoperative MRI and were treated surgically were included. The lesion conspicuity and accuracy for featuring AF were calculated by evaluating the three imaging datasets DWI, FS-PDW, and CE-T1W imaging, with surgical findings serving as the reference standard for the presence of fistulas. The statistical analysis included the application of the chi-square test and Kruskal-Wallis test.

RESULTS

In 65 patients with AF, 87 internal openings of AF were confirmed. In terms of the diagnostic accuracy of the internal openings, both FS-PDW and CE-T1W imaging sequences were significantly better than DWI sequences, and the difference was statistically significant (P < 0.05).

CONCLUSION

The FS-PDW imaging sequence showed comparable diagnostic performance of the internal opening of AF to CE-T1W imaging, which can provide an important diagnostic basis for clinical procedures.

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.

Predictors of outcome in cryptoglandular anal fistula according to magnetic resonance imaging: A systematic review

Background and Aims

Anal fistula (AF) with cryptoglandular origin tends to recur, and multiple risk factors are implicated. Recently, some magnetic resonance imaging (MRI) findings with predictive value for disease outcomes have been proposed. These intrinsic anatomic features include those of the AF and its surrounding structures. This study aims to clarify the prognostic role of MRI in AF.

Methods

We performed a systematic search of PubMed, Embase, and EBSCO databases. Two independent reviewers conducted the search and screened the articles. We selected studies that used MRI to assess AF and reported its relationship to disease outcome. We extracted data regarding the study design, type of intervention, outcome, MRI-measured items, and their significance.

Results

Out of 1230 retrieved articles, 18 were eligible for final inclusion, and a total of 4026 patients were enrolled in the selected studies. For preoperative MRI, the significant items affecting the outcome were the length of the fistula, horseshoe type, presence of multiple tracts, supralevator extension, and apparent diffusion coefficient (ADC) value. Other studies investigated the healing process using postoperative MRI.

Conclusion

This review found that MRI can be useful in the management of AF, both preoperatively and postoperatively. Factors, such as fistula length, horseshoe type, presence of multiple tracts, supralevator extension, and ADC value were found to be significantly associated with treatment outcomes. The presence of the fistula tract and the development of new abscesses on postoperative MRI was found to hinder the healing process. Further studies are needed to confirm these findings.

Sphincter-Preserving Fistulectomy Is an Effective Minimally Invasive Technique for Complex Anal Fistulas

Background

The optimal treatment of complex anal fistulas remains unclear, though many different sphincter-preserving procedures have been described. A minimally invasive technique with a better outcome is desired. The purpose of this study was to present a new technique—sphincter-preserving fistulectomy (SPF) and its clinical outcomes.

Materials and Methods

A retrospective study was performed to compare the efficacy and outcomes of SPF with ligation of the intersphincteric fistula tract (LIFT) in the management of complex anal fistulas in regards to postoperative pain, complications, wound healing time, recurrence, overall success rate, fecal continence function, and quality of life. Continence function was evaluated using the Wexner incontinence scale and anal manometry. The fecal incontinence quality of life (FIQL) scale was used to assess patients' quality of life.

Results

From June 2020 to July 2021, 41 patients with 43 SPF procedures and 35 patients with 35 LIFT procedures were included. Postoperative pain was comparable between two groups. The morbidity rate and the mean wound healing time in the SPF group were lower than those in the LIFT group (2.3% vs. 48.6%, p < 0.001; 1.4 ± 0.3 vs. 1.7 ± 0.4 months, p = 0.001). At a mean follow-up duration of 11.4 ± 3.5 months in the SPF group and 10.7 ± 4.3 months in the LIFT group, SPF achieved a better overall success rate than LIFT (97.7% vs. 77.1%, p = 0.014). Three patients in the SPF group and 4 patients in the LIFT group who all underwent a simultaneous fistulotomy procedure complained new incontinence of flatus. There was no statistical difference between the two groups in regards to the Wexner scores (p = 0.790), the maximum resting anal canal pressure (p = 0.641), the maximum squeeze pressure (p = 0.289), and the FIQL scores including lifestyle (p = 0.188), coping (p = 0.188), depression (p = 0.850), and embarrassment (p = 0.910).

Conclusions

SPF is a novel, safe, and effective minimally invasive technique for the management of complex anal fistulas, with a promising success rate and negligible impairment on continence. Future prospective studies are needed to evaluate the long-term outcomes of SPF.