Structured magnetic resonance imaging and endoanal ultrasound anal fistulas reporting template (SMART): An interdisciplinary Delphi consensus.

Twenty-six (26) transsphincteric anal fistulate with secondary high extension and sixteen (16) suprasphincteric anal fistulate with secondary high extensions have been treated successfully over a period of 3 years. The operative technique depends on exploration of the intersphincteric plane with removal of the primary source of the infection, together with excision of the primary tract, and drainage of he secondary high extensions. The patients have been followed for 2 years without recurrence. Continence for flatus and liquid feces was 92.1% and 96.15%, respectively, in the transsphincteric and 75% and 93.75%, respectively, in the suprasphincteric group but the continence for solid feces was 100% in both. Thus, the so-called excision technique for treatment of high fistula is safe and results are excellent.

To prospectively evaluate the relative accuracy of digital examination, anal endosonography, and magnetic resonance (MR) imaging for preoperative assessment of fistula in ano by comparison to an outcome-derived reference standard. Ethical committee approval and informed consent were obtained. A total of 104 patients who were suspected of having fistula in ano underwent preoperative digital examination, 10-MHz anal endosonography, and body-coil MR imaging. Fistula classification was determined with each modality, with reviewers blinded to findings of other assessments. For fistula classification, an outcome-derived reference standard was based on a combination of subsequent surgical and MR imaging findings and clinical outcome after surgery. The proportion of patients correctly classified and agreement between the preoperative assessment and reference standard were determined with trend tests and kappa statistics, respectively. There was a significant linear trend (P < .001) in the proportion of fistula tracks (n = 108) correctly classified with each modality, as follows: clinical examination, 66 (61%) patients; endosonography, 87 (81%) patients; MR imaging, 97 (90%) patients. Similar trends were found for the correct anatomic classification of abscesses (P < .001), horseshoe extensions (P = .003), and internal openings (n = 99, P < .001); endosonography was used to correctly identify the internal opening in 90 (91%) patients versus 96 (97%) patients with MR imaging. Agreement between the outcome-derived reference standard and digital examination, endosonography, and MR imaging for classification of the primary track was fair (kappa = 0.38), good (kappa = 0.68), and very good (kappa = 0.84), respectively, and fair (kappa = 0.29), good (kappa = 0.64), and very good (kappa = 0.88), respectively, for classification of abscesses and horseshoe extensions combined. Endosonography with a high-frequency transducer is superior to digital examination for the preoperative classification of fistula in ano. While MR imaging remains superior in all respects, endosonography is a viable alternative for identification of the internal opening.

The American Society of Colon and Rectal Surgeons (ASCRS) is dedicated to ensuring high-quality patient care by advancing the science and prevention and management of disorders and diseases of the colon, rectum, and anus. The Clinical Practice Guidelines Committee is composed of ASCRS members who are chosen because they have demonstrated expertise in the specialty of colon and rectal surgery. This committee was created to lead international efforts in defining quality care for conditions related to the colon, rectum, and anus and develop clinical practice guidelines based on the best available evidence. Although not proscriptive, these guidelines provide information on which decisions can be made and do not dictate a specific form of treatment. These guidelines are intended for the use of all practitioners, health care workers, and patients who desire information on the management of the conditions addressed by the topics covered in these guidelines. These guidelines should not be deemed inclusive of all proper methods of care nor exclusive of methods of care reasonably directed toward obtaining the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician considering all the circumstances presented by the individual patient. STATEMENT OF THE PROBLEM A generally accepted explanation for the cause of anorectal abscess and fistula-in-ano is that an abscess results from obstruction of an anal gland and that a fistula is caused by chronic infection and epithelialization of the abscess drainage tract.1–4 Anorectal abscesses are described by the anatomic space in which they develop; ischiorectal (also called ischioanal) abscesses are the most common followed by intersphincteric, supralevator, and submucosal locations.5–8 Anorectal abscess occurs more often in males than females, and although an abscess may develop at any age, the peak incidence is among 20- to 40-year-olds.4,8–12 In general, an abscess is treated with prompt incision and drainage.4,6,10,13 The diagnosis and treatment of necrotizing soft tissue infections and Fournier’s gangrene are beyond the scope of this guideline. Fistula-in-ano is an epithelialized tract that connects the perianal skin with the anal canal. In patients with an anorectal abscess, 30% to 70% present with a concomitant fistula-in-ano, and, of those who do not, approximately 30% to 50% will ultimately be diagnosed with a fistula in the months to years after abscess drainage.2,5,8–10,13–16 Although an anorectal abscess is described by the anatomic space in which it forms, a fistula-in-ano is classified in terms of its relationship with the internal and external anal sphincters (eg, the Parks classification; Table 1).16 In general, intersphincteric and transsphincteric fistulas are more frequently encountered than suprasphincteric, extrasphincteric, and submucosal tract locations.9,17–19 Anal fistulas may also be classified as “simple” or “complex.”20,21 Complex anal fistulas include transsphincteric fistulas that involve greater than 30% of the external sphincter, suprasphincteric, extrasphincteric, or horseshoe fistulas and anal fistulas associated with IBD, radiation, malignancy, preexisting fecal incontinence, or chronic diarrhea.20–22 Recurrent or branching fistulas may also be described as complex. Given the attenuated nature of the anterior sphincter in women, anterior fistulas deserve special consideration and may also be considered complex. Simple anal fistulas have none of these complex features and, in general, include intersphincteric and low transsphincteric fistulas that involve less than 30% of the external sphincter. TABLE 1. - Parks classification of fistula-in-ano Fistula type Description Submucosal Superficial fistula tract. Does not involve any sphincter muscle. Intersphincteric Crosses the internal sphincter and then has a tract to the perianal skin. Does not involve any external anal sphincter muscle. Transsphincteric Tracks from the internal opening at the dentate line via the internal and external anal sphincters and then terminates in the perianal skin or perineum. Suprasphincteric Courses superiorly into the intersphincteric space over the top of the puborectalis muscle and then descends through the iliococcygeus muscle into the ischiorectal fossa and into the perianal skin. Extrasphincteric Passes from the perineal skin through the ischiorectal fossa and levator muscles and then into the rectum and lies completely outside the external sphincter complex. Adapted from Parks et al.16 Distinct from cryptoglandular processes, anorectal abscess and fistula-in-ano can be manifestations of Crohn’s disease. Among patients with Crohn’s disease, fistula-in-ano has an incidence rate of 10% to 20% in population-based studies and 50% in longitudinal studies; meanwhile, nearly 80% of patients with Crohn’s disease who were cared for at tertiary referral centers may have a history of fistula-in-ano.23,24 In Crohn’s disease, anorectal abscesses and fistulas seem to result from penetrating inflammation rather than from infection of an anorectal gland.25 Patients with fistulas related to Crohn’s disease are typically managed with a multidisciplinary approach.26 Rectovaginal fistulas (RVFs), a unique subset of fistulas in many respects, may be classified as “low,” with a tract between the distal anal canal (at or below the dentate line) and the inside of the posterior fourchette; “high,” with a tract connecting the upper vagina (at the level of the cervix) with the rectum; and “middle” with a tract that lies in between these levels.27–29 The terms “anovaginal fistula” and “low rectovaginal fistula” may be used interchangeably. RVFs may also be classified as “simple” or “complex.” Simple RVFs have a low, small-diameter (<2 cm) communication between the anal canal and vagina and typically result from obstetrical injury or infection.29 “Complex” RVFs involve a higher tract between the rectum and vagina, are of a larger diameter, or result from radiation, cancer, or complications of pelvic surgical procedures.30–33 RVFs most commonly occur as a result of obstetric injury29 but may also occur in the setting of Crohn’s disease,25 malignancy, or infection,32 or as a complication of a failed colorectal anastomosis,33 an anorectal operation,34 or radiation therapy.35 The surgical treatment of a particular fistula is influenced by the patient’s presenting symptoms, unique anatomy of the fistula tract, quality of the surrounding tissues, and previous attempts at fistula repair.36 This guideline addresses the management of cryptoglandular fistulas, RVFs, and anorectal fistulas in the setting of Crohn’s disease. MATERIALS AND METHODS These guidelines were built on the last clinical practice guidelines for the management of anorectal abscess and fistula-in-ano published in 2016.37 An organized search was performed of MEDLINE, PubMed, Embase, and the Cochrane Database of Systematic Reviews between December 1, 2015, and November 5, 2021. Key word combinations using MeSH terms included abscess, fistula, fistula-in-ano, anal, rectal, perianal, perineal, rectovaginal, anovaginal, seton, fistulotomy, stem cell, advancement flap, ligation of intersphincteric fistula tract (LIFT), fistula plug, fistula glue, video-assisted anal fistula treatment (VAAFT), fistula laser closure (FiLaC), over-the-scope clip (OTSC) device, and Crohn’s disease. The search was restricted to English-language articles and studies of adult patients. Directed searches using embedded references from primary articles were performed in selected circumstances, and other sources including practice guidelines and consensus statements from relevant societies were also reviewed. The 841 screened articles were evaluated for their level of evidence, favoring clinical trials, meta-analysis/systematic reviews, comparative studies, and large registry retrospective studies during single-institutional series, retrospective reviews, and peer-reviewed, observational studies. A final list of 269 sources was evaluated for methodologic quality, the evidence base was analyzed, and a treatment guideline was formulated by the subcommittee for this guideline (Fig. 1). The final grade of recommendation and level of evidence for each statement were determined using the Grades of Recommendation, Assessment, Development, and Evaluation system (Table 2). When the agreement was incomplete regarding the evidence base or treatment guideline, consensus from the committee chair, vice chair, and 2 assigned reviewers determined the outcome. Members of the ASCRS Clinical Practice Guidelines Committee worked in joint production of these guidelines from inception to final publication (Table 3). The entire Clinical Practice Guidelines Committee reviewed the recommendations formulated by the subcommittee. Final recommendations were approved by the ASCRS Executive Council. In general, each ASCRS Clinical Practice Guideline is updated every 5 years. No funding was received for preparing this guideline, and the authors have declared no competing interests related to this material. This guideline conforms to the Appraisal of Guidelines for Research and Evaluation checklist. TABLE 2. - The GRADE system: grading recommendations Description Benefit versus risk and burdens Methodologic quality of supporting evidence Implications 1A Strong recommendation, high-quality evidence Benefits clearly outweigh risks and burdens or vice versa RCTs without important limitations or overwhelming evidence from observational studies Strong recommendation, can apply to most patients in most circumstances without reservation 1B Strong recommendation, moderate-quality evidence Benefits clearly outweigh risks and burdens or vice versa RCTs with important limitations (inconsistent results, methodologic flaws, indirect or imprecise) or exceptionally strong evidence from observational studies Strong recommendation, can apply to most patients in most circumstances without reservation 1C Strong recommendation, low- or very-low quality evidence Benefits clearly outweigh risks and burdens or vice versa Observational studies or case series Strong recommendation but may change when higher-quality evidence becomes available 2A Weak recommendation, high-quality evidence Benefits closely balanced with risks and burdens RCTs without important limitations or overwhelming evidence from observational studies Weak recommendation, best action may differ depending on circumstances or patients’ values or societal values 2B Weak recommendation, moderate-quality evidence Benefits closely balanced with risks and burdens RCTs with important limitations (inconsistent results, methodologic flaws, indirect or imprecise) or exceptionally strong evidence from observational studies Weak recommendation, best action may differ depending on circumstances or patients’ values or societal values 2C Weak recommendation, low- or very-low quality evidence Uncertainty in the estimates of benefits, risks, and burdens; benefits, risks, and burdens may be closely balanced Observational studies or case series Very weak recommendations; other alternatives may be equally reasonable GRADE = Grades of Recommendation, Assessment, Development, and Evaluation; RCT = randomized controlled trial.Adapted from Guyatt et al.38 Used with permission. TABLE 3. - What is new in the 2022 ASCRS Clinical Practice Guidelines for the management of anorectal abscess, fistula-in-ano, and rectovaginal fistula? 2022 New recommendations 11. Minimally invasive approaches to treat fistula-in-ano that use endoscopic or laser closure techniques have reasonable short-term healing rates but unknown long-term fistula healing and recurrence rates. Grade of recommendation: weak recommendation based on low-quality evidence, 2C. 19. Anorectal fistula associated with Crohn’s disease is typically managed with a combination of surgical and medical approaches. Grade of recommendation: strong recommendation based on moderate-quality evidence, 1B. 25. Local administration of mesenchymal stem cells is a safe and effective treatment for selected patients with refractory anorectal fistulas in the setting of Crohn’s disease. Grade of recommendation: weak recommendation based on moderate-quality evidence, 2B. 2022 Updated recommendations 5. Antibiotics should typically be reserved for patients with an anorectal abscess complicated by cellulitis, systemic signs of infection, or underlying immunosuppression. Grade of recommendation: weak recommendation based on moderate-quality evidence, 2C→2B. 9. A cutting seton may be used selectively in the management of complex cryptoglandular anal fistulas. Grade of recommendation: weak recommendations based on low-quality evidence, 2B→2C. 10. The anal fistula plug and fibrin glue are relatively ineffective treatments for fistula-in-ano. Grade of recommendation: strong recommendation based on moderate-quality evidence, 2B→1B. 21. Draining setons are typically useful in the multimodality therapy of fistulizing anorectal Crohn’s disease and may be used for long-term disease control. Grade of recommendation: strong recommendation based upon moderate-quality evidence, 1C→1B. 22. Symptomatic, simple, low anal fistulas in carefully selected patients with Crohn’s disease may be treated by lay-open fistulotomy. Grade of recommendation: weak recommendation based on low-quality evidence, 1C→ 2C. 23. Endorectal advancement flaps and the LIFT procedure may be used to treat fistula-in-ano associated with Crohn’s disease. Grade of recommendation: strong recommendation based on moderate-quality evidence, 2B→1B. ASCRS = American Society of Colon and Rectal Surgeons; LIFT = ligation of intersphincteric fistula tract. FIGURE 1.: PRISMA literature search flow sheet. PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses.Initial Evaluation of Anorectal Abscess and Fistula 1. A disease-specific history and physical examination should be performed evaluating symptoms, relevant history, abscess and fistula location, and presence of secondary cellulitis. Grade of recommendation: strong recommendation based on low-quality evidence, 1C. Anorectal abscess is usually diagnosed on the basis of a patient’s history and physical examination. Anorectal pain and swelling are common with superficial abscesses, whereas spontaneous drainage and fever occur less often.8–10,38 Deeper abscesses, including those in the supralevator or high ischiorectal spaces, may present with pain referred to the perineum, lower back, or buttocks.6,39,40 Evaluation of the anus and perineum may reveal erythema, calor, fluctuance, cellulitis, or tenderness on palpation or may be relatively unrevealing, particularly in patients with intersphincteric or deeper abscesses,6,10,40,41 and digital rectal examination and anoscopy/proctoscopy are occasionally needed to clarify the diagnosis. The differential diagnosis of anorectal abscess may include fissure, hemorrhoid thrombosis, pilonidal disease, hidradenitis, anorectal neoplasia, Crohn’s disease, and sexually transmitted infections.6,42,43 Patients who present with anal fistula typically report intermittent anorectal swelling and drainage. Relevant information about baseline anal sphincter function, history of anorectal operations, family history of IBD, obstetric history, and associated GI, genitourinary, or gynecologic pathology should typically be included in the patient’s history. Inspection of the perineum should involve noting the specific findings of an abscess, surgical scars, anorectal deformities, signs of possible anorectal Crohn’s disease, and the presence of an external fistula opening. Gentle probing of an external opening, when tolerated, may help confirm the presence of a fistula tract but should be done with care to avoid creating false tracts.43 Goodsall’s rule, that an anterior fistula-in-ano has a radial tract and a posterior fistula has a curvilinear tract to the anus, has generally proven to be accurate for anterior fistulas but is less accurate in cases with a posterior fistula.44–47 2. Routine use of diagnostic imaging is not typically necessary for patients with anorectal abscess or fistula. However, imaging may be considered in selected patients with an occult anorectal abscess, recurrent or complex anal fistula, immunosuppression, or anorectal Crohn’s disease. Grade of recommendation: strong recommendation based on moderate-quality evidence, 1B. In a retrospective study of 113 patients with anorectal abscess, the overall sensitivity of CT for detecting an abscess was 77% and the sensitivity of CT in immunosuppressed patients was 70%.48 An advantage of MRI over CT is its ability to identify anorectal abscesses and associated fistula tracts. In a study of 54 patients with anorectal Crohn’s disease, in which MRI and operative/clinical findings were compared, all the abscesses and 82% of the fistulas were correctly identified by MRI.49 In a 2014 prospective study of 50 patients with suspected anorectal fistula, MRI had a 95% sensitivity, 80% specificity, and 97% positive predictive value in detecting and grading the primary fistula tract.50 In a retrospective study of 136 patients specifically looking at the role of MRI in the preoperative assessment of fistula patients, Konan et al51 found that MRI identified “significant” findings defined as secondary (blind) tracts, horseshoe abscesses, or abscesses undiagnosed by physical examination or examination under anesthesia in 34% of patients. In this study, MRI provided significant findings more frequently for complex fistulas than for simple fistulas (54% vs 5%; p < 0.001). Additionally, the proportion of patients who had significant MRI contributions increased with increasing Parks grade (5% for grade 1; 48% for grade 2; 86% for grade 3; 87.5% for grade 4). A prospective trial published in 2019, including 126 patients, assessed the utility of 3-dimensional endoanal ultrasound (EAUS) and MRI in both simple (n = 68) and complex (n = 58) anal fistulas and reported comparable accuracy for the 2 modalities in cases of a simple fistula; however, MRI had significantly higher sensitivity evaluating secondary extensions in complex fistulas (97% vs 74%; p = 0.04).52 Endoanal ultrasound, in 2 or 3 dimensions and with or without peroxide enhancement, may be useful in the management of patients with abscess or fistula, and studies demonstrate concordance between EAUS and operative findings in 73% to 100% of cases.53–55 Tantiphlachiva et al56 found that preoperative EAUS may help preserve anorectal function in patients undergoing anal fistula surgery. This study retrospectively evaluated pre- and postoperative Fecal Incontinence Severity Scores in 109 patients who underwent preoperative EAUS and in 230 patients without preoperative imaging and found significantly worse Fecal Incontinence Severity Scores in the group that did not undergo preoperative EAUS at a mean follow-up of 34 weeks. The potential added value of combining diagnostic modalities to enhance the accuracy of anal fistula assessment was exemplified in a 2001 blinded study of 34 patients with anorectal Crohn’s disease in which EAUS was accurate in 91% of patients, MRI was accurate in 87% of patients, and examination under anesthesia was accurate in 91% of patients, whereas 100% accuracy was achieved when any 2 techniques were combined.57 The sensitivity, accuracy, and utility of transperineal ultrasound (TPUS), a noninvasive alternative to EAUS, have also been studied in patients with anorectal abscess, anoperineal fistulas, and RVFs.58–61 A prospective study of 23 patients with Crohn’s disease comparing the diagnostic accuracies of EAUS, TPUS, and MRI with operative findings found that the diagnostic accuracy of all 3 modalities was nearly identical.62 The authors concluded that TPUS might be considered first-line imaging because of its availability, low cost, and noninvasive nature, yet because of its operator dependency and lack of high-quality supporting data, this imaging technique has not gained widespread popularity. Anorectal Abscess 3. Patients with acute anorectal abscess should be treated promptly with incision and drainage. Grade of recommendation: strong recommendation based on low-quality evidence, 1C. The primary treatment of anorectal abscess remains surgical drainage. In general, the incision should be made large enough to provide adequate drainage while taking care not to injure the anal sphincter complex. The perianal incision should be kept as close as possible to the anal verge to minimize the length of a subsequent fistula tract should one develop. Alternatively, a surgical drain (eg, Pezzer, Malecot) can be placed into the abscess cavity63,64 if this provides adequate drainage, although this technique typically does not address loculations within an abscess cavity and generally omits primary fistulotomy. Small comparative analyses have shown comparable efficacy and higher patient satisfaction with drain placement compared to incision and drainage.65–67 Once an abscess has been drained, randomized trials report equivalent or superior abscess resolution rates with less pain and faster healing in patients whose wounds were left unpacked.68,69 After drainage, abscesses may recur in up to 44% of patients, most often within 1 year of initial treatment.2,10,70 Inadequate drainage, the presence of loculations or a horseshoe-type abscess, and not performing a primary fistulotomy are risk for recurrent abscess fistulotomy is addressed in recommendation Abscess generally a patient should have internal versus external drainage. Intersphincteric abscesses should typically be through the intersphincteric or into the anal canal via an internal it is usually to drain supralevator abscesses from the complicated of an intersphincteric abscess by the rectal to fistula supralevator abscesses because of of an ischiorectal abscess should typically be through the perianal These approaches to abscess drainage may help complex fistula that the can be to These abscesses most often involve the space and into the ischiorectal these circumstances, primary lay-open fistulotomy should typically be because these fistulas to be The a technique that the space and to address the ischiorectal spaces, is effective in the setting of a horseshoe although it may anal sphincter A technique using a posterior to the space seton placement has a high rate of abscess resolution and has been reported to preserve anorectal function compared to other operative Abscess drainage with concomitant fistulotomy may be performed in selected patients with simple anal fistulas. Grade of recommendation: weak recommendation based on moderate-quality evidence, 2B. Although 30% to 70% of patients with anorectal abscesses present with a concomitant the role of primary fistulotomy at the of abscess drainage remains Although a fistulotomy may address the and inflammation from the may the risk of a false tract when probing a fistula and can it to the the to the of sphincter randomized studies evaluating primary fistulotomy have reported results with to fistula recurrence and fecal and in a randomized controlled found that of patients treated with primary and internal had whereas reported postoperative sphincter at a follow-up of meanwhile, of 34 patients treated with incision and drainage had recurrence and reported postoperative and in a retrospective of patients treated with fistulotomy or sphincter found that after was significantly more common in patients who had a complex fistula compared to those who had a simple fistula A Cochrane that included patients from randomized controlled trials demonstrated that sphincter fistulotomy or at the of incision and drainage was associated with a significantly of abscess of fistula or abscess, or for subsequent 95% but an not incidence of at the randomized trials included in this patients with complex fistulas, recurrent abscesses, IBD, preexisting incontinence, or history of anorectal and included patients with low fistulas. Given the potential of a fistulotomy, have performing a fistulotomy with placement of a seton through the tract. A retrospective evaluated the of patients with low transsphincteric fistulas who underwent fistulotomy and then seton placement patients were patients who had anal sphincter function underwent a fistulotomy. This study reported that at 1 all patients who underwent fistulotomy reported no fistula or abscess recurrence or incontinence, supporting the of seton placement followed by fistulotomy in selected patients with a low transsphincteric When a simple fistula is encountered during incision and drainage of an anorectal abscess, fistulotomy may be performed in selected patients provided that the of healing the potential risk of fecal However, a seton to treat a fistula at the of incision and drainage patients to with a procedure to address their 5. Antibiotics should typically be reserved for patients with an anorectal abscess complicated by cellulitis, systemic signs of infection, or underlying immunosuppression. Grade of recommendation: weak recommendation based on moderate-quality evidence, 2B. In general, after performing an incision and drainage of a anorectal abscess in a patient does not healing or the recurrence rate and is typically not However, may be used selectively in patients with an anorectal abscess complicated by cellulitis, systemic or underlying Given the available evidence, the grade of this clinical practice guideline recommendation was from a 2C grade in to a 2B A retrospective study of patients with anorectal abscess who underwent incision and drainage with (n = or without (n = subsequent therapy for 5 to reported that of all patients related to anorectal infection, but was no significant between the in this Patients with surrounding cellulitis, or signs of systemic who did not had a in the rate of recurrent abscess compared with patients who received although this did not The authors also concluded that abscesses does not management or A study evaluated the of postoperative on fistula after incision and drainage of an anorectal In this randomized trial by and patients were treated with incision and drainage with or without a postoperative of and of patients in the treatment group an anal fistula versus 30% in the group < 0.001). to this study, et studied patients in a trial who no of with to anal fistula Although anorectal abscesses is not considered has been reported in up to of When is from an anorectal abscess, a combination of abscess drainage and directed the is typically for patients with systemic signs of or should also be considered in cases of recurrent infection or that an important role in treatment for or immunosuppressed patients with an anorectal Although patients with a higher and on examination typically have high resolution

This study aimed to evaluate the accuracy of a 3-dimensional volume render mode endoanal ultrasonography in the assessment of anal abscesses and fistulas. Three-dimensional endoanal ultrasonography was performed preoperatively in 62 patients with clinical diagnoses of an anal abscess and/or an anal fistula. The accuracy of a volume render mode endoanal ultrasonography was evaluated blindly by 2 observers through a retrospective analysis of all the stored images of anal abscesses and fistulas. Differences in classification of the type of anal abscesses and in determination of the type and location of internal openings of anal fistulas were assessed. In classification of the primary tract, the agreement between the volume render mode endoanal ultrasonography and surgery was much higher than that for the 3-dimensional endoanal ultrasonography (marginal homogeneity test P > .1, κ = 0.96, and marginal homogeneity test P = .0048, κ = 0.28, respectively). In localizing the internal openings and in classifying anal abscesses, the agreement for both methods with surgery was identical. The interobserver agreement showed complete agreement (100%) with regard to luminance and thickness parameters and very high accuracy for the opacity and filter parameters. This study demonstrated that volume render mode endoanal ultrasonography is a useful adjunct method to the 3-dimensional endoanal ultrasonography, showing better classification results of the types of anal fistulas.

Objective To investigate the imaging features of surgical complications of Crohn′s disease (CD). Methods The retrospective cross-sectional study was conducted. The clinical data of 128 CD patients with surgical complications who were admitted to the Sixth Affiliated Hospital of Sun Yat-sen University from January 2014 to December 2015 were collected. All the patients underwent computed tomography enterography (CTE), magnetic resonance enterography (MRE), magnetic resonance imaging (MRI) of anal tube and X-ray examination. The patients underwent surgical therapies after examinations. Observation indicators: (1) clinical characteristics of surgical complications of CD: occurrence of surgical complications of CD, correlation between preoperative complications and Montreal types of CD, (2) diagnostic accuracy of surgical complications and perianal lesions through CTE, MRE and MRI of anal tube, (3) imaging findings of preoperative complications of CD, (4) treatment and follow-up situations. Follow-up using telephone interview and outpatient examination was performed to detect the postoperative recovery and reoperations of patients up to March 2016. Count data were represented as frequency or percentage. The correlation between preoperative complications and Montreal types of CD was represented as the odds ratio (OR) and 95% confidence interval (CI). The features of diagnostic indexes were described as the sensitivity and specificity. Results (1) Clinical characteristics of preoperative complications of CD: all the 128 patients had preoperative complications, including 71 with anal fistula or anal fistula combined with perianal abscess, 26 with intestinal fistula, 24 with intestinal obstruction, 23 with abdominal abscess, 3 with digestive tract perforation, 1 with kidney stone and 1 with hydronephrosis. Of 128 patients, 12 had intestinal fistula combined with abdominal abscess, 1 had intestinal fistula combined with intestinal obstruction, 3 had intestinal fistula combined with abdominal abscess and intestinal obstruction, 1 had intestinal fistula combined with digestive tract perforation and 1 had intestinal fistula combined with hydronephrosis. There was a correlation between lesion location of CD and type of complications. Thirty-five of 51 patients had strictures or penetration-type lesions, with a correlation between strictures or penetration-type lesions and ileal CD [OR=6.23, 95% confidence interval (95%CI) : 2.86-13.61, P<0.05]. Fifty-six of 77 patients had anal fistula, showing a correlation between combined anal fistula and colonic lesions of CD (OR=6.40, 95%CI: 2.92-14.01, P<0.05). (2) Diagnostic accuracy of CTE, MRE and MRI of anal tube: with intraoperative exploration findings as the standard, the sensitivity and specificity of surgical complications of CD were 84% and 95% through CTE or MRE, and the sensitivity and specificity of anal fistula were 100% and 100% through MRI of anal tube. (3) Imaging findings of surgical complications of CD. ① Of 71 patients with anal fistula, 65 had 2 or more internal openings or fistula tract of complex anal fistula. The internal opening was a starting point of the fistula tract, and enhanced scans of MRI displayed punctate, shredded or small round abnormal strengthening signals between under mucous membrane of the anal canal and sphincter. The tubular and striped fistula tract was horizontal or vertical distribution, with a lightly high-high signal on T2 weighted-images (WI). The results of enhanced scans of MRI showed that there was an obvious homogeneous enhancement in the fistula tract or enhancement in the fistula tract wall, and no enhancement in the cavity of fistula tract. MRI findings in 38 patients combined with perianal abscess included a obvious high-signal on T2WI, and enhanced scans of MRI showed circular enhancement and no internal enhancement. ② Of 26 patients with intestinal fistula, 17 had intestinal fistula, imaging findings included multiple thickened intestinal walls and more obvious enhancement compared with normal intestinal canal. There was gathering and adhesions among intestinal canals, showing mash connections and petal-like changes. Fourteen patients had enterocutaneous fistula (6 combined with intestinal fistula and 1 patient combined with intestinal fistula and intestine-bladder fistula). Four patients had intestine-bladder fistula (2 combined with intestinal fistula and 1 combined with intestinal fistula and enterocutaneous fistula). One patient had intestine-vagina fistula. The results of CTE and MRE examinations showed that thickened intestinal canals and intestinal walls in the lesions, and shadows of intestinal canals communicated with the abdominal, bladder wall and vagina, with a high signal on T2WI and enhancement of intestinal wall by enhanced scan. The partial intestinal canals were physically close to other organs, without a connection between them, and anomalous enhancement or local pneumatosis among the adjacent organs were detected. ③ CTE findings of intestinal obstruction included constriction of intestinal canal combined with dilatation of proximal intestinal canal. There were 3 enhancement methods of thickened intestinal wall in 24 patients with intestine obstruction. Imaging findings of 12 patients included enhancement in the intestinal mucosa and no enhancement in the submucosa and muscularis mucosa. Imaging findings of 4 patients included enhancement of intestinal mucosa and muscularis mucosa and no enhancement in the submucosa. Imaging findings of 8 patients included homogenous and heterogeneous enhancements in the intestinal walls. ④ Twenty-three patients were complicated with abdominal abscess, including 15 combined with intestine fistula. The scans of CTE showed that there was a round-like or oval mass in the abdomen, with a high signal on T2WI, fluid-dominated inflammatory exudation around the mesentery, the enhancement of annular wall of mesentery and no enhancement of pus within the mesentery. ⑤ Three patients were combined with digestive tract perforation, including 1 combined with intestine fistula. CTE and X-ray detections showed there was a shadow of free gas in the intestinal mesentery and under abdominal diaphragm. ⑥ Two patients were combined with kidney stone and hydronephrosis. X-ray findings of kidney stone included the deposition of multiple and sharp-edged dense shadows within the renal calices. CTE findings of hydronephrosis included inflammatory thickening of ureteric wall with proximal ureter dilatation. (4) Treatment and follow-up situations: 128 patients underwent successful operation and were followed up for 4-27 months. Of 10 patients undergoing reoperations due to postoperative complications, MRI detection of 7 patients with recurrence of anal fistula showed fistula tract or abscess located at the previous loci was incompletely healed or progressed, morphous and location of lesions were roughly the same as the preoperative situations. The scans of CTE in 2 patients with anastomotic stricture showed that there were the thickening of intestinal wall and obstruction and dilatation at the proximal anastomotic-site. The enhanced scan of CTE in 1 patient with anastomotic fistula showed that there were irregularly cavity-like lesion beside the metal anastomotic ring, and effusion was seen within the lesions, with an edge enhancement. The other 118 patients recovered well without intestinal fistula or intestinal obstruction on CTE or MRE examination. Conclusions Anal fistula is the most common surgical complication of CD, and intestinal fistula, intestinal obstruction and abdominal abscess are also relatively common. The early postoperative complications consist of the recurrence of anal fistula. Location of lesions in CD is associated with the type of complications. CTE or MRE and anal MRI findings have different imaging characteristics for CD combined with different complications, with a certain value in the assessment of abdominal and perianal complications. Key words: Crohn′s disease; Surgical complications; Tomography, X-ray computed; Magnetic resonance imaging

Our objective was to assess if contrast-enhanced (CE) anal endosonography (AES) with hydrogen peroxide is useful in the diagnosis of anal and ano-vaginal fistulas. A Bruel and Kjaer scanner with a 7.0-MHz transducer was used. After visualization of the fistula tract in non-contrast (NC) AES, hydrogen peroxide was introduced into the fistula tract through the external opening in 22 patients with different types of anal fistulas. Both CE and NC AES revealed 13 transsphincteric, 3 intersphincteric, 2 suprasphincteric and 4 ano-vaginal fistulas. Simple tracts were found in 16 cases and complex in 6 cases in non-contrast AES. The CE AES revealed 19 simple and 3 complex fistulas. Fifteen internal openings visible in NC AES were confirmed in CE AES in 6 cases, which additionally found 11 more internal openings. Surgery confirmed all types of fistulas found in NC and CE AES; however, the latter two found 18 simple and 4 complex fistulas, and 21 internal openings. Both NC and CE AES are able to correctly differentiate types of anal fistulas and are of comparable value in differentiating simple from complex fistulas, although a false-negative result was found in CE AES. In the preoperative assessment of the internal opening, CE AES is superior to NC AES.

PurposeTo retrospectively assess the accuracy of magnetic resonance imaging (MRI) in defining dentate line in anal fistula.Materials and methodsSeventy patients with anal fistulas were assessed by dynamic contrast-enhanced MRI. The distance from the dentate line to the anal verge for all patients was measured by MRI. To mitigate interference, 35 patients with anal fistulas whose internal openings were located on the dentate line were excluded from this study. Two observers independently judged the positional relationship between the internal opening and the MRI-defined dentate line, and compared with the results observed by surgeon to assess the accuracy.ResultsThe distance between the MRI-defined dentate line and the anal verge depended on the location of the internal opening and the morphology of the anal canal mucosa. The distance based on the location the internal opening and the morphology of the anal canal mucosa was 18.2 ± 8.1 mm and 20.0 ± 5.3 mm on oblique coronal T2WI, respectively. Compared with the results observed by the surgeon, the accuracy of evaluating the positional relationship between the internal opening and the dentate line from the morphology of the anal canal mucosa on MRI exceeded 89.9%. Taking 18.2–20.0 mm as the distance between the dentate line and the anal verge on the MRI image, the accuracy of evaluating the relationship between the position of the internal opening and the dentate line was over 85.7%. Considering both the dentate line and the anal canal mucosa, the accuracy of evaluating the relationship between the internal opening and the dentate line was over 91.5%. The results of MRI-defined dentate line were in good agreement with the results of intraoperative surgeon evaluation, and the κ values were 0.70, 0.63, and 0.78, respectively.ConclusionMRI has high accuracy in defining the dentate line in anal fistulas.

To assess agreement between endoanal sonography, endoanal magnetic resonance (MR) imaging, and surgery in depiction and classification of fistula in ano. Twenty-eight consecutive patients with nonspecific, cryptoglandular fistula in ano were studied. The fistulas were classified with endoanal sonography, endoanal MR imaging, and surgery. Agreement between the modalities was also evaluated. Classification of fistulas was possible in 17 of 28 patients (61%) with sonography, in 25 of 28 (89%) with MR imaging, and in 26 of 28 (93%) with surgery. Concordance between endoanal sonography and MR imaging occurred in 46% of the cases (kappa = 0.27, poor agreement); between sonography and surgery in 36% (kappa = 0.09, no agreement); and between MR imaging and surgery in 64% (kappa = 0.43, moderate agreement). Endoanal MR imaging more accurately allows depiction and classification of fistula in ano than endoanal sonography.

Anal fistula is a benign inflammatory disease with unclear etiology which develops in approximately 10 in 100 000 adult patients. Surgical treatment of fistulae is associated with a risk of damaging anal sphincters. This usually happens in treating high fistulae, branched fistulae, and anterior ones in females. In preoperative diagnosis of anal fistulae, endosonography and magnetic resonance imaging play a significant role in planning the surgical technique. The majority of fistulae are diagnosed in endosonography, but magnetic resonance is performed when the presence of high fistulae, particularly branched ones, and recurrent is suspected.The aim of this paperThe aim of this paper was to compare the roles of the two examinations in preoperative assessment of high anal fistulae.Material and methodsThe results of endosonographic and magnetic resonance examinations performed in 2011–2012 in 14 patients (4 women and 10 men) with high anal fistulae diagnosed intraoperatively were subject to a retrospective analysis. The patients were aged from 23 to 66 (mean 47). The endosonographic examinations were performed with the use of a BK Medical Pro Focus system with endorectal 3D transducers with the frequency of 16 MHz. The magnetic resonance scans were performed using a Siemens Avanto 1.5 T scanner with a surface coil in T1, T1FS, FLAIR, T2 sequences and in T1 following contrast medium administration. The sensitivity and specificity of endosonography and magnetic resonance imaging were analyzed. A surgical treatment served as a method for verification. The agreement of each method with the surgery and the agreement of endosonography and magnetic resonance imaging were compared in terms of the assessment of the fistula type, localization of its internal opening and branches. The agreement level was determined based on the percentage of consistent assessments and Cohen's coefficient of agreement, κ. The integrity of the anal sphincters was assessed in each case.ResultsIn determining the fistula type, magnetic resonance imaging agreed with intraoperative assessment in 79% of cases, and endosonography in 64% of cases. Endosonography agreed with magnetic resonance in 57% of cases. In the assessment of internal opening, the agreement between endosonography and intraoperative assessment was 65%, between magnetic resonance and intraoperative assessment – 41% and between endosonography and magnetic resonance – 53%. In the assessment of fistula branches, endosonography agreed with intraoperative assessment in 67% of cases, magnetic resonance in 87% of cases, and the agreement between the two methods tested was 67%.ConclusionsMagnetic resonance is a more accurate method than endosonography in determining the type of high fistulae and the presence of branches. In assessing the internal opening, endosonography proved more accurate. The agreement between the two methods ranges from 53–67%; the highest level of agreement was noted for the assessment of branching.

Fistula is considered to be any abnormal passage which connects two epithelial surfaces. Parks fistula classification demonstrates the biggest practical significance and divides fistulae into inter-sphincteric, trans-sphincteric, supra-sphincteric, and extra-sphincteric. Diagnostic method options are retrograde (RTG) fistulography, computed tomography (CT) fistulography, and magnetic resonance imaging (MRI) of pelvic organs. The purpose of the study is to correlate clinical examination and operative findings with the findings of MRI and to draw efficacy of MRI as a preoperative diagnostic tool in the management of fistula in ano. This study was performed at the Surgery Department and MRI unit of the Radiology Department of JLNH and RC, Bhilai, from January 2014 to July 2015. Patients with perianal fistulae were included in our prospective study. All patients underwent high-spatial resolution MR imaging. MR imaging findings were correlated with the intraoperative surgical finding. MR imaging shows 7 fistulous patients with side branching and 16 with abscess cavity which was 100% intraoperatively correlated. Fifty-six patients out of 60 completely correlated with MRI for primary track which was clinically significant. MRI had 96% sensitivity and 100% specificity for primary tract and internal opening and 100% sensitivity and specificity for abscess and multiple tracks. MRI is useful in successful treatment of perianal fistulae by providing more accurate anatomical information about the amount of sphincter above the track and the position and level of the internal opening, thereby increasing the likelihood of successful surgical treatment. So, MRI is the very important preoperative investigation tool for fistula in ano.

Treatment of anal fistulas is still a challenging task because of high recurrence and risk of incontinence. Identification of internal fistula opening is paramount for successful treatment. Goodsall's rule is commonly used to predict the course of fistula and internal opening. However, its accuracy has been questioned by many investigators and its role became a controversial topic. This is a case series prospective study in which 320 consecutive patients with anal fistula with Mean age 48.9± 6 years ages (ranges from 16 to 64years) and mean body mass index 24.8± 5.5 average 18.5-30.6) were enroled. Goodsall's rule was applied to all fistulas according to the site of external fistula opening. Location of internal fistula opening as suggested by Goodsall's rule then compared to the exact location of internal opening identified by perineal or pelvic MRI and intraoperative findings. to assess the accuracy and positive predictive value of the Goodsall's rule in predicting the internal opening of the tract. The overall accuracy rate, positive predictive value (PPV), sensitivity and specificity of Goodsall's rule in this study were 74.75%, 77.1, 74.5, and 72.05, respectively. The accuracy in predicting the internal fistula opening was 52.4% in anterior tracts and 73% in posterior tracts. Goodsall's rule was found to be more accurate in posterior fistulas than anterior fistulas and in short superficial fistulas rather than in long and high fistulas. Goodsall's rule was accurate in 74.75% of anal fistulas. It was more accurate for posterior long fistulas and anterior short and superficial fistulas. Patients with long (>3cm) anterior fistulas defied Goodsall's rule when they found to have fistulas tracking to a midline anterior origin. Further, short posterior fistulas were found to open more commonly in a direct radial course rather to midline posteriorly.

To explore the diagnostic value of magnetic resonance imaging(MRI) in anal fistula. A total of 2160 patients were clinically diagnosed with anal fistula at the Sixth Affiliated Hospital of Sun Yat-sen University from March 2010 to September 2015. Among them, 232 cases with operative history at other hospital, 218 with Crohn's disease, 6 with rectum cancer and 8 with other disease were excluded, and 1696 patients were finally enrolled and retrospectively analyzed. The saggital FSE T2WI imaging was confirmed based on the midline of body, and then the coronal and axial scanning line were confirmed. The key point was that the coronal scanning line must parallel and the axial scanning line must be perpendicular to the major axis of anal canal. The characteristics of anal fistula were recorded, and anal fistula were classified as five types, including intersphincteric, transphincteric, suprasphincteric, extrasphincteric and superficial fistula according to the Parks classification and our experience. The distribution of internal opening was described by using lithotomy position clock method. Of 1696 patients, 1456 were males and 240 females with median age of 26.5 (0.2 to 87.0) years. Age of 8.4% (143/1696) cases was under 20 years old, of 57.4%(973/1696) cases was between 20 to 40, of 28.4%(482/1696) cases was between 40 to 60, of 5.8%(98/1696) cases was over 60. The 1696 MR examinations included 1128 on 1.5T MR and 568 on 0.5T MR. Of all the anal fistulas was 29.0%(492) high position and 71.0%(1204) was low position. Among the 1696 patients, 1057 were intersphincteric fistulas(62.3%), 407 were transphincteric fistulas(24.0%), 68 were suprasphincteric fistulas(4.0%), 54 were extrasphincteric fistulas (3.2%), 67 were superficial fistulas(4.0%), and 43(2.5%) were difficult to classify. A total of 1996 internal openings were found and most of them were located around the dentate line of 5-7 o'clock in lithotomy position(47.7%, 952/1996). Anal fistula mainly occur in young men, and the most common type is intersphincteric fistula. MRI can accurately classify anal fistulas and clearly demonstrate internal openings, and provide reliable evidence for clinical treatment and surgery.

A commentary on “Risk factors for postoperative recurrence of anal fistula identified by an international, evidence-based Delphi consultation survey of surgical specialists” (Int J Surg 2021; 92:106038)

We assessed whether contrast-enhanced anal endosonography (AES) with hydrogen peroxide improves the identification of anal fistulas and their internal openings compared with non-contrast AES. The study group comprised 12 patients who had various types of anal fistulas with visible external openings. AES was performed before and about 15 seconds after injection of 1 ml of 3% hydrogen peroxide into the fistula tract through the external opening. Both contrast and non-contrast AES revealed 7 transsphincteric, 2 intersphincteric, 1 suprasphincteric, and 2 anovaginal fistulas. Simple tracts were found in 8 cases and complex tracts in 4 cases on non-contrast AES. Contrast-enhanced AES revealed 9 simple and 3 complex fistulas. One fistula that appeared complex on the non-contrast study appeared simple after contrast agent administration. Contrast-enhanced AES demonstrated more internal openings than non-contrast AES did. Surgery confirmed 11 of the fistulas; an internal opening could not be located surgically for the other tract. Contrast-enhanced AES appears to be superior to non-contrast AES in the preoperative assessment of anal and anovaginal fistulas and in demonstrating and locating their internal openings.

Aim: Fistula-in-ano is a well described disease but no definitive surgical technique has been developed. We conducted a retrospective cohort study in a single center to evaluate patients who underwent surgical treatment of a perianal fistula from 2012 to 2018 in our hospital. The aim of the study was to compare the outcome of different surgical techniques (Fistulotomy/fistulectomy and seton, Video-Assisted Anal Fistula Treatment (VAAFT), Micro-fragmented adipose tissue injection, Lipogems®).Methods: A cohort of 103 patients with anal fistula who qualified for elective surgery between 2012 and 2018 were recruited at Sant’Anna Hospital in Ferrara. All patients underwent a digital rectal examination and preoperative magnetic resonance imaging (MRI) to identify the fistula tract and internal opening. Patients were divided into 4 groups, one for each type of surgery they underwent: Fistulotomy/fistulectomy and seton, Video-Assisted Anal Fistula Treatment (VAAFT), Micro-fragmented adipose tissue injection, Lipogems®). Numerical rating scale (NRS) was used to assess subjective pain one week after surgery and documented. The scale ranged from 0 to 10, where 0 stands for no pain and 10 stands for worst pain ever faced. Primary end point was fistula recurrence at 1 year of follow-up. Secondary end point was evaluation of post-operative pain. Results: There were 71 males and 32 females, with a median age of 50 years (range 21-89 years). Among them, 79 patients were newly diagnosed, the other 24 patients had undergone previous surgery and had recurrence. In total, 118 surgical operation were performed for anal fistula. During the follow-up period, anal fistula recurrence was observed in 13 patients after VAAFT, 3 patients after Micro-fragmented adipose tissue injection, 4 after fistulotomy, 12 after fistulectomy, 10 after seton placement and 8 after Lipogems® technique. One week after surgery, pain was evaluated by all patients on a scale from 0 to 10. The mean scores of patients who underwent VAAFT, micro-fragmented adipose tissue injection, fistulotomy, fistulectomy, seton placement and Lipogems® technique were 1 (0-5), 1.5 (0-8), 5 (3-8), 6.8 (5-9), 4.2 (2-6) and 0 (0-2), respectively. Conclusion: This study presents the difficulties in managing anal fistulas and the variety of surgical options. VAAFT and Micro-fragmented adipose tissue injection appear to be safe and feasible options in the management of anal fistula, and short-term healing rates are acceptable with no sustained effect on continence. There is, however, a paucity of robust data with long-term outcomes. These techniques are thus welcome additions. Lipogems ® technique is a safe and reproducible procedure, unfortunately according to our experience, it does not promote fistula healing in patients with recurrent inter-sphincteric anal fistula. We do not suggest the use of this technique as a first-line treatment.