Utility of Endoanal Ultrasonography in Assessment of Primary and Recurrent Anal Fistulas and for Detection of Associated Anal Sphincter Defects

Contemporary management of anorectal fistula

Anorectal fistula is a common, chronic condition, and is primarily managed surgically. Herein, we provide a contemporary review of the relevant etiology and anatomy anorectal fistula, treatment recommendations that summarize relevant outcomes and alternative considerations, in particular when to refer to a fistula expert.

Impact of Preoperative Three-Dimensional Endoanal Ultrasound on the Surgical Outcome of Primary Fistula in Ano. A Multi-Center Observational Study of 253 Patients

PURPOSE

To evaluate the impact of preoperative three-dimensional endoanal ultrasound (3D-EAUS) on the clinical outcome of anal fistula surgery.

METHODS

The research consisted of multi-center retrospective case-control study including 253 consecutive adult patients undergoing surgery for confirmed or suspected primary fistula in ano who had undergone preoperative 3D-EAUS evaluation between January 2011 and January 2021. Main outcome measures were the concordance (K value) between ultrasound results and surgery in the identification of fistulas internal openings, primary tracts and secondary extensions and the 6 and 12 months success rate in patients with concordant and discordant findings.

RESULTS

A good agreement in the identification of the main fistulas characteristics between ultrasound results and operative findings was found. A significant difference (P < .0001; Fisher's exact test) in the success rate was found between patients with concordant and discordant ultrasound results and operative findings in identification or location of internal opening. Particularly, all the 11 (4.8%) patients with discordant results experimented a failure of the surgical procedure at 6 months follow-up. At re-operation, the shift from discordant to concordant results was associated with an 81.8% 12 months success-rate.

CONCLUSION

The three-dimensional endoanal ultrasound preoperative evaluation may have a relevant impact on the outcome of a defined group of patients undergoing surgery for anal fistula, since the careful evaluation of ultrasound results could simplify the internal orifice intra-operative detection and improve the success rate.

Endorectal advancement flap compared to ligation of inter-sphincteric fistula tract in the treatment of complex anal fistulas: A meta-analysis of randomized clinical trials

BACKGROUND

Rectal advancement flap and ligation of intersphincteric fistula tract are common procedures for treating complex anal fistula. The present meta-analysis aimed to compare the surgical outcomes of advancement flap and ligation of intersphincteric fistula tract.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant systematic review of randomized clinical trials comparing the ligation of intersphincteric fistula tract and advancement flap was conducted. PubMed, Scopus, and Web of Science were searched through January 2023. The risk of bias was assessed using the Risk of Bias 2 tool and certainty of evidence with the Grading of Recommendations Assessment, Development and Evaluation approach. The primary outcomes were healing and recurrence of anal fistulas, and secondary outcomes were operative time, complications, fecal incontinence, and early pain.

RESULTS

Three randomized clinical trials (193 patients, 74.6% male) were included. The median follow-up was 19.2 months. Two trials had a low risk of bias, and 1 had some risk of bias. The odds of healing (odds ratio: 1.363, 95% confidence interval: 0.373-4.972, P = .639), recurrence (odds ratio: 0.525, 95% confidence interval: 0.263-1.047, P = .067), and complications (odds ratio: 0.356, 95% confidence interval: 0.085-1.487, P = .157) were similar between the 2 procedures. Ligation of intersphincteric fistula tract was associated with a significantly shorter operation time (weighted mean difference: -4.876, 95% confidence interval: -7.988 to -1.764, P = .002) and less postoperative pain (weighted mean difference: -1.030, 95% confidence interval: -1.418 to -0.641, 0.198, P < .001, I² = 3.85%) than advancement flap. Ligation of intersphincteric fistula tract was associated with marginally lower odds of fecal incontinence than advancement flap (odds ratio: 0.27, 95% confidence interval: 0.069-1.06, P = .06).

CONCLUSION

Ligation of intersphincteric fistula tract and advancement flap had similar odds of healing, recurrence, and complications. The odds of fecal incontinence and extent of pain after ligation of intersphincteric fistula tract were lower than after advancement flap.

A pilot randomized controlled trial on ligation of intersphincteric fistula tract (LIFT) versus modified parks technique and two-stage seton in treatment of complex anal fistula

Complex anal fistula (CAF) is a challenging condition for surgeons. This randomized trial aimed to compare ligation of the intersphincteric fistula tract (LIFT), modified Parks technique, and two-stage seton in the treatment of complex anal fistula in terms of the success of treatment and complications. This was a pilot randomized trial conducted in the period of January 2019 to December 2019 on adult patients with CAF who were allocated to one of three groups: LIFT, modified Parks technique, and two-stage seton. The main outcome measures were healing rates, time to healing, complications, operation time, and quality of life. Sixty-six patients (75.7% males) of a mean age of 45.2 years were included. Mean operation time of LIFT was significantly shorter than the other two procedures (p < 0.0001). There was a significant difference between the three groups in terms of success rate (p = 0.04) but not in regard to complications (p = 0.59). The modified Parks technique had a significantly higher success rate than LIFT (95.2% vs 68.1%, p = 0.045) whereas the success rates of two-stage seton and LIFT were not significantly different (86.9% vs 68.1%, p = 0.16). The average time to healing after LIFT was significantly shorter than the other two procedures. The quality-of-life scores were comparable among the three groups. There was a significant difference in healing rates after the three procedures as the modified Parks technique achieved the highest success rate followed by two-stage seton and then the LIFT procedure. Time to complete healing after LIFT was significantly shorter than the other two procedures. The three procedures achieved similar quality of life and complication rates.

Using preoperative three-dimensional endoanal ultrasound to determine operative procedure in patients with perianal fistulas

AIM

Accurate preoperative identification of perianal fistula tracts and internal openings can facilitate the choice of surgical procedure and may lead to improved healing rates. Our aim was to explore the effectiveness of three-dimensional endoanal ultrasound (3D-EAUS) in determining the type of perianal fistula and planning operative management.

METHOD

This was a cohort longitudinal study. Patients with perianal fistulas from January 2017 to January 2018 who underwent 3D-EAUS and subsequent surgery were included. Intra-operative findings were considered as standard for comparison with clinical examination and 3D-EAUS findings. The primary outcome measure was to evaluate the concordance between 3D-EAUS and intra-operative findings and the secondary outcome measure was healing rates.

RESULTS

Sixty-eight patients with a mean age of 43.1 ± 14.1 years were included. Twenty-eight patients had inter-sphincteric (41.2%) and 40 (14 high and 26 low) trans-sphincteric fistulas (58.8%). 3D-EAUS, clinical examination and intra-operative exploration could predict the location of internal openings in 62/68 (91.2%), 48/68 (70.5%) and 56/68 (82.4%) patients, respectively. Hydrogen peroxide (H₂O₂)-enhanced 3D-EAUS accurately predicted the location of internal openings when compared with 3D-EAUS without H₂O₂ (concordance K = 0.963, P = 0.05). High concordance rates were seen between intra-operative and 3D-EAUS findings on the type of perianal fistula. No significant difference was seen between the suggested surgical treatment based on 3D-EAUS and the eventual surgical treatment (P > 0.05). Study limitations were the small sample size and lack of randomization.

CONCLUSION

3D-EAUS may be considered as a first-line investigation for patients with perianal fistulas because of high concordance with intra-operative assessment and facilitation of surgical planning.

Recurrent anal fistulas: When, why, and how to manage?

Anal fistula is a commonly encountered anal condition in the surgical practice. Despite being a benign condition, anal fistula remains to represent a surgical challenge, particularly the complex type of fistulas. One of the common complications of anal fistula surgery is the persistence or recurrence of the pathology, both defined as failure of surgery. Recurrent anal fistulas after previous surgery represent an even more challenging problem since they are usually associated with a higher risk of re-recurrence and continence disturbance. The present review aimed to shed light on various aspects of recurrent anal fistulas, including the different definitions of failure after surgery, risk factors of recurrence, problems associated with management of recurrent fistulas, and assessment and treatment of recurrent anal fistulas.

Effects of preoperative endoanal ultrasound on functional outcome after anal fistula surgery

Objective

Endoanal ultrasound (EAUS) is a recommended preoperative investigation for fistula-in-ano (FiA) which aims to provide the best chance of healing and preservation of continence function. This study aims are (1) to assess effect of EAUS on functional outcome and (2) to determine factors associated with clinical outcomes after FiA surgery.

Design

Retrospective analysis of subjects with cryptogenic FiA between January 2011 and December 2016, in a tertiary hospital, was performed by comparing EAUS and no-EAUS groups. Postoperative change in St. Mark’s faecal incontinence severity score (cFISS=FISS at 6 months after surgery–FISS before surgery) were compared. General linear model was used to determine factors associated with cFISS. Binary logistic regression was used to assess factors related to clinical outcomes. A p-value of <0.05 is considered significant.

Results

We enrolled 339 subjects; 109 (M:F 91:18, mean age 41.7±13.6 years) of 115 in EAUS group and 230 in no-EAUS group (M:F 195:35, mean age 42.6±13.0 years). There were higher proportions of recurrent cases (24.8% vs 13.9%, p=0.014) and complex FiA (80.7% vs 50.4%, p=0.001) in EAUS group. Postoperative FISS (mean±SE) were increased in both groups; preoperative versus postoperative FISS were 0.36±0.20 versus 0.59±0.25 in EAUS group (p=0.056) and 0.31±0.12 versus 0.76±0.17 in no-EAUS group (p<0.001). EAUS had significant effects on cFISS in both univariate analysis, F(1,261)=4.053, p=0.045; and multivariate analysis, F(3,322)=3.147, p=0.025, Wilk’s Lambda 0.972. Other associated factors included recurrent fistula (F(3,322)=0.777, p=0.007, Wilk’s Lambda 0.993) and fistula classification (F(3,322)=16.978, p<0.001, Wilk’s Lambda 0.863). After a mean follow-up of 33.6±28.6 weeks, success rate was 63.3%(EAUS) and 60% (no-EAUS), p=0.822. Factors associated with clinical outcomes were fistula complexity, number of tracts, recurrence, number of previous surgery and type of operations. Accuracy of EAUS was 90.8% and not related to clinical outcomes (p=0.522).

Conclusion

EAUS had favourable effects on functional outcome after FiA surgery while multiple factors were associated with clinical outcomes. EAUS is useful, accurate, inexpensive and can be the first tool for planning of complex and recurrent FiA.

Preoperative assessment of simple and complex anorectal fistulas: Tridimensional endoanal ultrasound? Magnetic resonance? Both?

PURPOSE

The purpose of the study is to evaluate the diagnostic value of tridimensional endoanal ultrasound (3D-EAUS) and magnetic resonance (MR) in the preoperative assessment of both simple and complex anorectal fistulas.

METHODS

All the patients referred for the treatment of anal fistulas were enrolled in this study and underwent, as preoperative assessment, anamnestic evaluation, clinical examination, and unenhanced and H2O2-enhanced 3D-EAUS and MR. The results of imaging evaluation were compared with surgical findings, considered as reference standard.

RESULTS

During the study period, 124 patients operated on for anal fistulas underwent complete preoperative imaging assessment. Perfect agreement between 3D-EAUS and surgery in the anal fistulas' severity grading was found (K = 1). The fistulas were classified as simple in 68/126 (53.9%) and complex in 58/126 (46.03%) cases, according to fistulas' Parks' classification and the most recent American Guidelines. In both simple and complex anal fistulas, 3D-EAUS did not show a significantly higher accuracy in the evaluation of internal openings, if compared with MR (P = 0.47; McNemar's Chi-square test). In the complex anal fistulas, MR showed a significantly higher accuracy in the evaluation of secondary extensions if compared with 3D-EAUS (P = 0.041; McNemar's Chi-square test), whereas in the simple anal fistulas, no significant difference was found.

CONCLUSION

In the preoperative work-up of patients with anorectal fistulas, 3D-EAUS may represent the first-line diagnostic tool. In cases of fistulas classified as complex by 3D-EAUS, MR may be indicated as adjunctive diagnostic imaging examination, to more carefully describe the fistulas' complete anatomy.