Impact of three-dimensional endoanal ultrasound on the outcome of anal fistula surgery: a prospective cohort study

Fistula development after anal abscess drainage-a multicentre retrospective cohort study

PURPOSE

Anal abscesses are common and, despite correct treatment with surgical drainage, carry the risk of developing fistulas. Studies identifying risk factors for the development of anal fistulas are sparse. This study aimed to identify the risk factors for anal fistulas after anal abscess surgery.

METHODS

This was a multicentre, retrospective cohort study of patients undergoing acute surgery for anal abscesses in the Capital Region of Denmark between 2018 and 2019. The patients were identified using ICD-10 codes for anal abscesses. Predefined clinicopathological factors and postoperative courses were extracted from patient records.

RESULTS

A total of 475 patients were included. At a median follow-up time of 1108 days (IQR 946-1320 days) following surgery, 164 (33.7%) patients were diagnosed with an anal fistula. Risk factors for developing fistulas were low intersphincteric (OR 2.77, 95CI 1.50-5.06) and ischioanal (OR 2.48, 95CI 1.36-4.47) abscesses, Crohn's disease (OR 5.96, 95CI 2.33-17.2), a history of recurrent anal abscesses (OR 4.14, 95CI 2.47-7.01) or repeat surgery (OR 5.96, 95CI 2.33-17.2), E. coli-positive pus cultures (OR 4.06, 1.56-11.4) or preoperative C-reactive protein (CRP) of more than 100 mg/L (OR 3.21, 95CI 1.57-6.71).

CONCLUSION

Several significant clinical risk factors were associated with fistula development following anal abscess surgery. These findings are clinically relevant and could influence the selection of patients for specialised follow-up, facilitate expedited diagnosis, and potentially prevent unnecessarily long treatment courses.

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.

Preoperative Assessment of Perianal Fistulas with Combined Magnetic Resonance and Tridimensional Endoanal Ultrasound: A Prospective Study

BACKGROUND

we designed a prospective study of diagnostic accuracy that compared pelvic MRI and 3D-EAUS with pelvic MRI alone in the preoperative evaluation and postoperative outcomes of patients with perianal fistulas.

METHODS

the sample size was 72 patients and this was divided into two imaging groups. MRI alone was performed on the first group. Both MRI and 3D-EAUS were performed in parallel on the second group. Surgical exploration took place after two weeks and was the standard reference. Park's classification, the presence of a concomitant abscess or a secondary tract, and the location of the internal opening were recorded. All patients were re-evaluated for complete fistula healing and fecal incontinence six months postoperatively. All of the collected data were subjected to statistical analysis.

RESULTS

the MRI group included 36 patients with 42 fistulas. The MRI + 3D-EAUS group included 36 patients with 46 fistulas. The adjusted sensitivity and negative predictive value were 1.00 for most fistula types in the group that underwent combined imaging. The adjusted specificity improved for intersphincteric fistulas in the same group. The adjusted balanced accuracy improved for all fistula types except rectovaginal. The combination of imaging methods showed improved diagnostic accuracy only in the detection of a secondary tract. The healing rate at six months was 100%. Fecal incontinence at six months did not present a statistically significant difference between the two groups (Fisher's exact test p-value > 0.9). Patients with complex perianal fistulas had a statistically significant higher probability of undergoing a second surgery (x2 test p-value = 0.019).

CONCLUSIONS

the combination of pelvic MRI and 3D-EAUS showed improved metrics of diagnostic accuracy and should be used in the preoperative evaluation of all patients with perianal fistulas, especially those with complex types.

A Systematic Review of Epidemiology and Outcomes Associated with Local Surgical and Intersphincteric Ligation Procedures for Complex Cryptoglandular Fistulas

INTRODUCTION

This systematic literature review (SLR) assessed incidence/prevalence of cryptoglandular fistulas (CCF) and outcomes associated with local surgical and intersphincteric ligation procedures for CCFs.

METHODS

Two trained reviewers searched PubMed and Embase for observational studies evaluating the incidence/prevalence of cryptoglandular fistula and clinical outcomes of treatments for CCF after local surgical and intersphincteric ligation procedures for CCF.

RESULTS

In total 148 studies met a priori eligibility criteria for all cryptoglandular fistulas and all intervention types. Of those, two assessed incidence/prevalence of cryptoglandular fistulas. Eighteen reported clinical outcomes of surgeries of interest in CCF and were published in the past 5 years. Prevalence was reported as 1.35/10,000 non-Crohn's patients, and 52.6% of non-IBD patients were found to progress from anorectal abscess to fistula over 12 months. Primary healing rates ranged from 57.1% to 100%; recurrence occurred in a range of 4.9-60.7% and failure in 2.8-18.0% of patients. Limited published evidence suggests postoperative fecal incontinence and long-term postoperative pain were rare. Several of the studies were limited by single-center design with small sample sizes and short follow-up durations.

DISCUSSION

This SLR summarizes outcomes from specific surgical procedures for the treatment of CCF. Healing rates vary according to procedure and clinical factors. Differences in study design, outcome definition, and length of follow-up prevent direct comparison. Overall, published studies offer a wide range of findings with respect to recurrence. Postsurgical incontinence and long-term postoperative pain were rare in the included studies, but more research is needed to confirm rates of these conditions following CCF treatments.

CONCLUSION

Published studies on the epidemiology of CCF are rare and limited. Outcomes of local surgical and intersphincteric ligation procedures show differing success and failure rates, and more research is needed to compare outcomes across various procedures. (PROSPERO; registration number CRD42020177732).

Comparison of the Diagnostic Accuracy of Percutaneous Fistula Contrast-Enhanced Ultrasound Combined with Transrectal 360° 3-D Imaging and Conventional Transrectal Ultrasound in Complex Anal Fistula

This study compared the diagnostic accuracy of percutaneous fistula contrast-enhanced ultrasound (CEUS) combined with 360° 3-D transrectal ultrasound (TRUS) imaging (CEUS + 360°-TRUS) with that of conventional transrectal ultrasound in the diagnosis of complex anal fistulas. A total of 156 patients clinically diagnosed with complex anal fistula from January 2020 to December 2021 were studied and randomly divided into an experimental group (n = 82) and a control group (n = 74). Patients in the experimental group were examined by percutaneous fistula CEUS combined with CEUS + 360°-TRUS, while patients in the control group were examined using TRUS. The detection of fistulas (main tract, branch and internal orifice) and the accuracy of Parks classification were compared between the two groups. Recurrences were followed up at 1, 3 and 6 mo after the surgery. A total of 156 patients were included, aged 23-68 y (average: 37.7 ± 18.2 y). In both groups, the course of disease was &lt;1 mo in 128 cases, 1-2 mo in 22 cases and &gt;3 mo in 6 cases. A total of 474 fistulas were confirmed by surgery in the aforementioned patients, including 224 main fistulas, 250 branch pipes and 254 internal orifices. The CEUS + 360°-TRUS group had 96.87%, 90.41% and 90.14% diagnostic accuracy for the main tract, branch and internal orifice, which was statistically significant (p &lt; 0.001) compared with the 85.00%, 70.00% and 72.46% for the TRUS group, respectively. The overall accuracy of Parks classification of anal fistula in the CEUS + 360°-TRUS group was significantly higher than that in the TRUS group (90.24% vs. 78.38%, p &lt; 0.001). After 6 mo of follow-up, the recurrence rate in the CEUS + 360°-TRUS group was 4.87%, and the recurrence rate in the TRUS group was 18.91%. Percutaneous fistula CEUS combined with transrectal 360° 3-D imaging has significantly higher accuracy than conventional TRUS in the diagnosis of complex anal fistula, especially for anal fistula branches, internal openings and Parks classification and is beneficial in reducing post-operative occurrence of complex anal fistulas.

Perianal fistulas: A review with emphasis on preoperative imaging

PURPOSE

We aim to present a comprehensive literature review which focuses on the preoperative imaging of perianal fistulas.

MATERIAL/METHODS

Pelvic magnetic resonance imaging (MRI) and endoanal ultrasound (EAUS) are the two first-line imaging modalities for the preoperative evaluation of patients with perianal fistulas. We conducted a search in PubMed, Scopus and Google Scholar concerning articles comparing pelvic MRI with EAUS, which were published from 1994 until 2019.

RESULTS

In most articles, pelvic MRI is superior to EAUS for the evaluation of perianal fistulas (especially for supralevator and extrasphincteric ones). Preoperative pelvic MRI is associated with statistically significant better results and prognosis after surgical treatment of the disease. Preoperative EAUS poses high sensitivity and specificity in identifying intersphincteric and transsphincteric perianal fistulas, as well as the internal opening of a fistula-in-ano. There is only one meta-analysis which compares the diagnostic accuracy of the two mentioned imaging modalities in preoperative fistula detection. Sensitivity of both - pelvic MRI and EAUS, is acceptably high (0.87). Specificity of pelvic MRI is 0.69 in comparison to EAUS (0.43), but both values are considered low.

CONCLUSIONS

Future well-designed prospective studies are needed to investigate the diagnostic accuracy of pelvic MRI and EAUS in the preoperative assessment of patients with perianal fistulas. Moreover, the combination of pelvic MRI and EAUS should also be studied, since several published articles suggest that it could lead to improved diagnostic accuracy. A novel treatment algorithm for perianal fistulas could arise from this study.

A Multicenter Randomized Controlled Trial Comparing Safety, Efficacy, and Cost-effectiveness of the Surgisis Anal Fistula Plug Versus Surgeon's Preference for Transsphincteric Fistula-in-Ano: The FIAT Trial

OBJECTIVE

To undertake a randomized comparison of the Biodesign Surgisis anal fistula plug against surgeon's preference in treating cryptoglandular transsphincteric fistula-in-ano.

SUMMARY BACKGROUND DATA

The efficacy of the Biodesign Surgisis anal fistula plug in healing anal fistulae is uncertain.

METHODS

Participants were randomized to the fistula plug with surgeon's preference (advancement flap, cutting seton, fistulotomy, Ligation of the Intersphincteric Fistula Tract procedure). The primary outcome was faecal incontinence quality of life (FIQoL) at 12-months. Secondary outcomes were fistula healing, incontinence rates, and complication and reintervention rates.

RESULTS

Between May 2011 and March 2016, 304 participants were randomized to fistula plug or surgeon's preference. No differences were seen in FIQoL between the 2 groups at 12 months. Clinical fistula healing was reported in 66/122 (54%) of the fistula plug and 66/119 (55%) of the surgeon's preference groups at 12 months. Fecal incontinence rates improved marginally in both the groups. Complications and reinterventions were frequent, with significantly more complications in the fistula plug group at 6-weeks (49/142, 35% vs 25/137, 18%; P=0.002). The mean total costs were £2738 (s.d. £1151) for the fistula plug and £2308 (s.d. £1228) for the surgeon's preference group (mean difference +£430, P=0.0174). The average total quality adjusted life years (QALYs) gained was marginally higher in the fistula plug group. The fistula plug was 35% to 45% likely to be cost-effective across a willingness to pay threshold of £20,000 to £30,000 / QALY.

CONCLUSIONS

The Biodesign Surgisis anal fistula plug is associated with similar FIQoL and healing rates to surgeon's preference at 12 months. Higher costs and highly uncertain gains in QALYs mean that the fistula plug may not be considered as a cost-effective treatment in the UK NHS.

Treatment Strategy for Perianal Fistulas in Crohn Disease Patients: The Surgeon's Point of View

Perianal fistula is a frequent complication and one of the subclassifications of Crohn disease (CD). It is the most commonly observed symptomatic condition by colorectal surgeons. Accurately classifying a perianal fistula is the initial step in its management in CD patients. Surgical management is selected based on the type of perianal fistula and the presence of rectal inflammation; it includes fistulotomy, fistulectomy, seton procedure, fistula plug insertion, video-assisted ablation of the fistulous tract, stem cell therapy, and proctectomy with stoma creation. Perianal fistulas are also managed medically, such as antibiotics, immunomodulators, and biologics including anti-tumor necrosis factor-alpha agents. The current standard treatment of choice for perianal fistula in CD patients is the multidisciplinary approach combining surgical and medical management; however, the rate of long-term remission is low and is reported to be 50% at most. Therefore, the optimum management strategy for perianal fistulas associated with CD remains controversial. Currently, the goal of management for CD-related perianal fistulas are controlling symptoms and maintaining long-term anal function without proctectomy, while monitoring progression to anorectal carcinoma. This review evaluates perianal fistula in CD patients and determines the optimal surgical management strategy based on recent evidence.

Three-dimensional virtual reconstruction as a tool for preoperative planning in the management of complex anorectal fistulas

The making of three-dimensional virtual models is a promising technology in preoperative planning, but that is not used in the treatment of anorectal fistulas. The objective of this work is to describe the development and initial experience of the construction of a virtual three-dimensional model of the pelvic anatomy of a patient, allowing the exact identification of the relationships between the fistulous tracts of complex anorectal fistulas and the other pelvic structures. An MRI was performed on this patient, and the images were exported to the Vitrea fX Workstation® software. A radiologist did the analysis and segmentation of the images that were then sent to a three-dimensional image processor (Meshlab v. 1.3.3 – ISTI – CNR Research Center, Pisa University, Italy). The final 3D color image was analyzed by the surgeon and used to guide the catheterization of the fistulous pathways, the internal orifice and to assist in the identification of adjacent structures. The final three-dimensional model presented a high correlation with the intraoperative findings and facilitated the surgical planning.

Anal fistula plug versus surgeon's preference for surgery for trans-sphincteric anal fistula: the FIAT RCT

BACKGROUND

The aim of fistula surgery is to eradicate the disease while preserving anal sphincter function. The efficacy of the Surgisis^® anal fistula plug (Cook Medical, Bloomington, IN, USA) in the treatment of trans-sphincteric fistula-in-ano has been variably reported.

OBJECTIVES

To undertake a randomised comparison of the safety and efficacy of the Surgisis anal fistula plug in comparison with surgeon's preference for the treatment of trans-sphincteric anal fistulas.

DESIGN

A randomised, unblinded, parallel-arm, prospective, multicentre clinical trial.

SETTING

Hospitals in the UK NHS involving colorectal surgeons accredited by the Association of Coloproctology of Great Britain and Ireland.

PARTICIPANTS

Adult patients suffering from trans-sphincteric fistula-in-ano of cryptoglandular origin.

INTERVENTIONS

Patients were randomised on a 1 : 1 basis to either the fistula plug or the surgeon's preference [e.g. fistulotomy, cutting seton, advancement flap or ligation of intersphincteric fistula tract (LIFT) procedure].

MAIN OUTCOME MEASURES

The primary outcome measure was quality of life as measured by the Faecal Incontinence Quality of Life (FIQoL) questionnaire at 12-month follow-up. Secondary outcome measures included clinical and radiological fistula healing rates, faecal incontinence rates, complications rates, reintervention rates and cost-effectiveness.

RESULTS

Between May 2011 and March 2016, 304 participants were recruited (152 fistula plug vs. 152 surgeon's preference). No difference in FIQoL score between the two trial groups was seen at the 6-week, 6-month or 12-month follow-up. Clinical evidence of fistula healing was reported in 66 of 122 (54%) participants in the fistula plug group and in 66 of 119 (55%) participants in the surgeon's preference group at 12 months. Magnetic resonance imaging (MRI) showed fistula healing in 54 of 110 (49%) participants in the fistula plug group and in 63 of 112 (56%) participants in the surgeon's preference group. Variation in 12-month clinical healing rates was observed: 55%, 64%, 75%, 53% and 42% for fistula plug, cutting seton, fistulotomy, advancement flap and LIFT procedure, respectively. Faecal incontinence rates were low at baseline, with small improvement in both groups post treatment. Complications and reinterventions were frequent. The mean total costs were £2738 [standard deviation (SD) £1151] in the fistula plug group and £2308 (SD £1228) in the surgeon's preference group. The average total quality-adjusted life-years (QALYs) gain was much smaller in the fistula plug group (0.829, SD 0.174) than in the surgeon's preference group (0.790, SD 0.212). Using multiple imputation and probabilistic sensitivity analysis, and adjusting for differences in baseline EuroQol-5 Dimensions, three-level version utility, there was a 35-45% chance that the fistula plug was as cost-effective as surgeon's preference over a range of thresholds of willingness to pay for a single QALY of £20,000-30,000.

LIMITATIONS

Limitations include a smaller sample size than originally calculated, a lack of blinding that perhaps biased patient-reported outcomes and a lower compliance rate with MRI at 12-month follow-up.

CONCLUSIONS

The Surgisis anal fistula plug is associated with similar FIQoL score to surgeon's preference at 12-month follow-up. The higher costs and highly uncertain and small gains in QALYs associated with the fistula plug mean that this technology is unlikely to be considered a cost-effective use of resources in the UK NHS.

FUTURE WORK

Further in-depth analysis should consider the clinical and MRI characteristics of fistula-in-ano in an attempt to identify predictors of fistula response to treatment.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN78352529.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 21. See the NIHR Journals Library website for further project information.

Risk Factors for Recurrence after anal fistula surgery: A meta-analysis

BACKGROUND

Despite a burgeoning literature during the last two decades regarding perioperative risk management of anal fistula, little is known about its risk factors that influence postoperative recurrence. We performed a meta-analysis to summarize and assess the credibility of evidence of potential risk factors for anal fistula recurrence (AFR) after surgery.

METHODS

Pubmed and EMBASE without language restriction were searched from inception to April 2018 that reported risk factors which predisposed recurrence after anal fistula surgery. We excluded studies that involved patients with anal fistula associated with Crohn's disease. MOOSE guidelines were followed when this meta-analysis was performed. We used random-effects models to pool relative risks (RRs) with 95% confidence intervals (CIs). Evidence from observational studies was graded into high-quality (Class I), moderate-quality (Class II/III) and low-quality (Class IV) based on Egger's P value, total sample size and between-study heterogeneity.

RESULTS

Of 3514 citations screened, 20 unique observational studies comprising 6168 patients were involved in data synthesis. High-quality evidence showed that AFR was associated with high transsphincteric fistula (RR, 4.77; 95% CI, 3.83 to 5.95), internal opening unidentified (RR, 8.54; 95% CI, 5.29 to 13.80), and horseshoe extensions (RR, 1.92; 95% CI, 1.43 to 2.59). Moderate-quality evidence suggested an association with prior anal surgery (RR, 1.52; 95% CI, 1.04 to 2.23), seton placement surgery (RR, 2.97; 95% CI, 1.10 to 8.06), and multiple fistula tract (RR, 4.77; 95% CI, 1.46 to 15.51). High-quality evidence demonstrated no significant association with gender or smoking; moderate-quality evidence also suggested no association with age, tertiary referral, alcohol use, diabetes mellitus, obesity, preoperative seton drainage, high internal opening, postoperative drainage, mucosal advancement flap surgery, supralevator extensions, location or type of anal fistula.

CONCLUSION

Several patient, surgery and fistula-related factors are significantly associated with postoperative AFR. These findings strengthen clinical awareness of early warning to identify patients with high-risk disease recurrence for AFR.

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.

EFSUMB Recommendations for Gastrointestinal Ultrasound Part 3: Endorectal, Endoanal and Perineal Ultrasound

This article represents part 3 of the EFSUMB Recommendations and Guidelines for Gastrointestinal Ultrasound (GIUS). It provides an overview of the examination techniques recommended by experts in the field of endorectal/endoanal ultrasound (ERUS/EAUS), as well as perineal ultrasound (PNUS). The most important indications are rectal tumors and inflammatory diseases like fistula and abscesses in patients with or without inflammatory bowel disease (IBD). PNUS sometimes is more flexible and convenient compared to ERUS. However, the technique of ERUS is quite well established, especially for the staging of rectal cancer. EAUS also gained ground in the evaluation of perianal diseases like fistulas, abscesses and incontinence. For the staging of perirectal tumors, the use of PNUS in addition to conventional ERUS could be recommended. For the staging of anal carcinomas, PNUS can be a good option because of the higher resolution. Both ERUS and PNUS are considered excellent guidance methods for invasive interventions, such as the drainage of fluids or targeted biopsy of tissue lesions. For abscess detection and evaluation, contrast-enhanced ultrasound (CEUS) also helps in therapy planning.

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.

The treatment of anal fistula: second ACPGBI Position Statement - 2018

It is over 10 years since the first ACPGBI Position Statement on the management of anal fistula was published in 2007. This second edition is the result of scrutiny of the literature published during this time; it updates the original Position Statement and reviews the published evidence surrounding treatments for anal fistula that have been developed since the original publication.

3D high-resolution anorectal manometry in patients with perianal fistulas: comparison with 3D-anal ultrasound

BACKGROUND

Perianal fistula surgery can damage the anal sphincters which may cause faecal incontinence. By measuring regional pressures, 3D-HRAM potentially provides better guidance for surgical strategy in patients with perianal fistulas. The aim was to measure regional anal pressures with 3D-HRAM and to compare these with 3D-EUS findings in patients with perianal fistulas.

METHODS

Consecutive patients with active perianal fistulas who underwent both 3D-EUS and 3D-HRAM at a clinic specialised in proctology were included. A group of 30 patients without fistulas served as controls. Data regarding demographics, complaints, previous perianal surgical procedures and obstetric history were collected. The mean and regional anal pressures were measured with 3D-HRAM. Fistula tract areas detected with 3D-EUS were analysed with 3D-HRAM by visual coding and the regional pressures of the corresponding and surrounding area of the fistula tract areas were measured. The study was granted by the VUmc Medical Ethical Committee.

RESULTS

Forty patients (21 males, mean age 47) were included. Four patients had a primary fistula, 19 were previously treated with a seton/abscess drainage and 17 had a recurrence after previously performed fistula surgery. On 3D-HRAM, 24 (60%) fistula tract areas were good and 8 (20%) moderately visible. All but 7 (18%) patients had normal mean resting pressures. The mean resting pressure of the fistula tract area was significantly lower compared to the surrounding area (47 vs. 76 mmHg; p < 0.0001). Only 2 (5%) patients had a regional mean resting pressure < 10 mmHg of the fistula tract area. Using a Δ mean resting pressure ≥ 30 mmHg difference between fistula tract area and non-fistula tract area as alternative cut-off, 21 (53%) patients were identified. In 6 patients 3D-HRAM was repeated after surgery: a local pressure drop was detected in one patient after fistulotomy with increased complaints of faecal incontinence.

CONCLUSIONS

Profound local anal pressure drops are found in the fistula tract areas in patients normal mean resting pressures. Fistulotomy may affect local sphincter pressure. This might influence surgical decision making in future.

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

BACKGROUND

Tridimensional endoanal ultrasonography (3D-EAUS) has been used for the assessment of various anorectal lesions. Previous studies have reported good accuracy of 3D-EAUS in preoperative assessment of fistula-in-ano (FIA). This study aimed to assess the diagnostic utility of 3D-EAUS in preoperative evaluation of primary and recurrent FIA and its role in detection of associated anal sphincter (AS) defects.

PATIENTS AND METHODS

Prospectively collected data of patients with FIA who were investigated with 3D-EAUS were reviewed. The findings of EAUS were compared with the intraoperative findings, the reference standard, to find the degree of agreement regarding the position of the internal opening (IO) and primary tract (PT), and presence of secondary tracts using kappa (k) coefficient test. A subgroup analysis was performed to compare the accuracy and sensitivity of EAUS for primary and recurrent FIA.

RESULTS

Of the patients, 131 were included to the study. EAUS had an overall accuracy of 87, 88.5, and 89.5% in detection of IO, PT, and AS defects, respectively. There was very good concordance between the findings of EAUS and intraoperative findings for the investigated parameters (kappa = 0.748, 0.83, 0.935), respectively. Accuracy and sensitivity of EAUS in recurrent FIA were insignificantly lower than primary cases. EAUS detected occult AS defects in 5.3% of the patients studied.

CONCLUSION

The diagnostic utility of 3D-EAUS was comparable in primary and recurrent FIA. 3D-EAUS was able to detect symptomatic and occult AS defects with higher accuracy than clinical examination.

Three-dimensional endoanal ultrasound is accurate and reproducible in determining type and height of anal fistulas

AIM

Surgical treatment of high anal fistulas is associated with the potential risk of faecal incontinence and recurrence. The primary aim of this study was to determine the accuracy of three-dimensional endoanal ultrasound (3D-EAUS) in the assessment of height and type of anal fistulas, compared to the intra-operative findings (gold standard). The secondary aim was to evaluate the inter-observer reproducibility of 3D-EAUS.

METHOD

The study design was a prospective analysis of retrospective data. 299 patients (202 men), mean age 45.3 years, who underwent surgery for anal fistulas, were included. All patients were preoperatively assessed by 3D-EAUS. Two readers independently reviewed the volumes to determine the type and height of fistulas. Sensitivity, specificity, positive and negative predictive values, proportion of agreements and Cohen's kappa coefficient (κ) were calculated for both examiners. Ultrasound findings were compared with intra-operative data (reference standard), evaluated blindly by the surgeons.

RESULTS

At surgery, 201 (67%) were transsphincteric, 49 (16%) suprasphincteric, 47 (16%) intersphincteric and two (1%) extrasphincteric fistulas. Intra-operatively, 177 (59%) were low and 122 (41%) high fistulas. The overall accuracy of 3D-EAUS was 91% for fistula type (271/299 fistulas: 97% transsphincteric, 100% intersphincteric, 57% suprasphincteric, 0% extrasphincteric) and 92% for fistula height (275/299 fistulas: 80% high and 100% low). Both readers reported very good agreement with surgery in the assessment of fistula type (proportion of agreement 0.88, κ = 0.89) and height (proportion of agreement 0.90, κ = 0.91).

CONCLUSIONS

3D-EAUS is an accurate and reproducible modality for the assessment of type and height of anal fistulas.