MR imaging classification of perianal fistulas and its implications for patient management

Quantifying 18F-Fluorodeoxyglucose Uptake in Perianal Fistulas on PET/CT: A Retrospective Analysis

RATIONALE AND OBJECTIVES

The use of 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT) in assessing inflammatory diseases has shown significant promise. Uptake patterns in perianal fistulas, which may be an incidental finding on PET/CT, have not been purposefully studied. Our aim was to compare FDG uptake of perianal fistulas to that of the liver and anal canal in patients who underwent PET/CT for hematologic/oncologic diagnosis or staging.

MATERIALS AND METHODS

We retrospectively identified patients who underwent FDG-PET/CT imaging between January 2011 and May 2023, where the report described a perianal fistula or abscess. PET/CTs of patients included in the study were retrospectively analyzed to record the maximum standardized uptake value (SUVmax) of the fistula, abscess, anal canal, rectum, and liver. Fistula-to-liver and Fistula-to-anus SUVmax ratios were calculated. We statistically compared FDG activity among the fistula, liver, and anal canal. We also assessed FDG activity in patients with vs. without anorectal cancer, as well as across different St. James fistula grades.

RESULTS

The study included 24 patients with identifiable fistulas. Fistula SUVmax (mean=10.8 ± 5.28) was significantly higher than both the liver (mean=3.09 ± 0.584, p < 0.0001) and the anal canal (mean=5.98 ± 2.63, p = 0.0005). Abscess fistula SUVmax was 15.8 ± 4.91. St. James grade 1 fistulas had significantly lower SUVmax compared to grades 2 and 4 (p = 0.0224 and p = 0.0295, respectively). No significant differences existed in SUVmax ratios between anorectal and non-anorectal cancer groups.

CONCLUSION

Perianal fistulas have increased FDG avidity with fistula SUVmax values that are significantly higher than the anal canal.

Cellular angiofibroma arising from the rectocutaneous fistula in an adult: A case report

BACKGROUND

Rectocutaneous fistulae are common. The infection originates within the anal glands and subsequently extends into adjacent regions, ultimately resulting in fistula development. Cellular angiofibroma (CAF), also known as an angiomyofibroblastoma-like tumor, is a rare benign soft tissue neoplasm predominantly observed in the scrotum, perineum, and inguinal area in males and in the vulva in females. We describe the first documented case CAF that developed within a rectocutaneous fistula and manifested as a perineal mass.

CASE SUMMARY

In the outpatient setting, a 52-year-old male patient presented with a 2-year history of a growing perineal mass, accompanied by throbbing pain and minor scrotal abrasion. Physical examination revealed a soft, well-defined, non-tender mass at the left buttock that extended towards the perineum, without a visible opening. The initial assessment identified a soft tissue tumor, and the laboratory data were within normal ranges. Abdominal and pelvic computed tomography (CT) revealed swelling of the abscess cavity that was linked to a rectal cutaneous fistula, with a track-like lesion measuring 6 cm × 0.7 cm in the left perineal region and attached to the left rectum. Rectoscope examination found no significant inner orifices. A left medial gluteal incision revealed a thick-walled mass, which was excised along with the extending tract, and curettage was performed. Histopathological examination confirmed CAF diagnosis. The patient achieved total resolution during follow-up assessments and did not require additional hospitalization.

CONCLUSION

CT imaging supports perineal lesion diagnosis and management. Perineal angiofibromas, even with a cutaneous fistula, can be excised transperineally.

Current update on the role of endoanal ultrasound: a primer for radiologists

Endoanal ultrasound (EAUS) is a valuable imaging modality for the evaluation of anal and perianal pathologies. It provides detailed information about the anatomy and physiology of the anorectal region and has been used in pre-and post-operative settings of anorectal pathologies. EAUS is not only useful in the evaluation of benign pathologies but also in loco-regional staging of anal and rectal tumors. EAUS has several advantages over MRI, including reduced cost, better patient tolerance, and improved scope of application in patients with contraindications to MRI. Despite its benefits, EAUS is not widely performed in many centers across the globe. This article aims to educate radiologists, trainees, and surgeons about the indications, contraindications, patient preparation, imaging technique, and findings of EAUS. We will also highlight the technical difficulties, diagnostic challenges, and procedural complications encountered during EAUS, along with a comparative analysis of EAUS with other imaging approaches.

Dynamic contrast-enhanced MR imaging in identifying active anal fistula after surgery

BACKGROUND

It is challenging to identify residual or recurrent fistulas from the surgical region, while MR imaging is feasible. The aim was to use dynamic contrast-enhanced MR imaging (DCE-MRI) technology to distinguish between active anal fistula and postoperative healing (granulation) tissue.

METHODS

Thirty-six patients following idiopathic anal fistula underwent DCE-MRI. Subjects were divided into Group I (active fistula) and Group IV (postoperative healing tissue), with the latter divided into Group II (≤ 75 days) and Group III (> 75 days) according to the 75-day interval from surgery to postoperative MRI reexamination. MRI classification and quantitative analysis were performed. Correlation between postoperative time intervals and parameters was analyzed. The difference of parameters between the four groups was analyzed, and diagnostic efficiency was tested by receiver operating characteristic curve.

RESULTS

Wash-in rate (WI) and peak enhancement intensity (PEI) were significantly higher in Group I than in Group II (p = 0.003, p = 0.040), while wash-out rate (WO), time to peak (TTP), and normalized signal intensity (NSI) were opposite (p = 0.031, p = 0.007, p = 0.010). Area under curves for discriminating active fistula from healing tissue within 75 days were 0.810 in WI, 0.708 in PEI, 0.719 in WO, 0.783 in TTP, 0.779 in NSI. All MRI parameters were significantly different between Group I and Group IV, but not between Group II and Group III, and not related to time intervals.

CONCLUSION

In early postoperative period, DCE-MRI can be used to identify active anal fistula in the surgical area.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: ChiCTR2000033072.

Comparing the Efficacy of a Combination of Diffusion-Weighted Imaging and T2-STIR (Short Tau Inversion Recovery) Imaging With Contrast-Enhanced MRI in the Evaluation of Perianal Fistula

BACKGROUND

Perianal fistula is clinically diagnosed and commonly characterized using magnetic resonance imaging (MRI). Diffusion-weighted imaging (DWI) and T2-weighted imaging are emerging techniques that can obviate the need for contrast injection in cases where contrast administration is not feasible or contraindicated. The main objective of our study was to compare the efficacy of the combination of DWI and T2 STIR (short tau inversion recovery) imaging with contrast-enhanced MRI for the diagnosis and characterization of perianal fistula.

METHODS

Sixty-nine patients with clinical perianal fistula with at least one external opening were evaluated with DWI, T2 STIR, and contrast MRI. A comparative cross-sectional study was conducted in the Department of Radiodiagnosis and Imaging, All India Institute of Medical Sciences, Bhopal, India. The chi-square test was done to find the association between categorical variables. The Kappa test was done to estimate the agreement between two different tests in measuring the outcome. The validity of tests was measured using sensitivity, specificity, positive predictive value, negative predictive value, and accuracy.

RESULTS

The combination of DWI and T2 STIR is equivalent to contrast-enhanced MRI in the evaluation of primary and complicated perianal fistula. The combination of DWI and T2 STIR is superior to DWI alone in the classification and characterization of perianal fistula. However, DWI is superior to T2 STIR in differentiating perianal inflammation with abscess from perianal inflammation without abscess and can be used as an alternative to post-contrast fat-suppressed T1-WI in the detection of perianal abscesses and disease activity.

CONCLUSION

DWI can be used as an adjunct to T2 STIR, and the combination of DWI and T2 STIR can replace the post-contrast fat-suppressed T1 MRI sequence in the classification and characterization of perianal fistula.

Can Short Tau Inversion Recovery (STIR) Imaging Be Used as a Stand-Alone Sequence To Assess a Perianal Fistulous Tract on MRI? A Retrospective Cohort Study Comparing STIR and T1-Post Contrast Imaging

INTRODUCTION

Perianal fistulas demand precise preoperative assessment for optimal surgical outcomes. MRI, using Short Tau Inversion Recovery (STIR) and T1-post contrast sequences, plays a crucial role in this evaluation.This retrospective cohort study compared STIR imaging's diagnostic efficacy with T1-post contrast sequences in identifying perianal fistulous tracts. The study investigated whether STIR imaging could serve as the sole diagnostic sequence, simplifying clinical practice.

METHODS

In a tertiary care hospital, 100 patients underwent pelvic MRI for suspected perianal fistulas. Radiologists independently evaluated STIR and T1-post contrast sequences for internal openings, tract extent, distinction, abscess presence, and tract type. Sensitivity, specificity, area under the curve (AUC), and Cohen's kappa analysis were used for diagnostic assessment.

RESULTS

STIR imaging showed notable sensitivity (79.8-97.9%) and specificity (100%) for identifying internal openings and tracts. Combined with T1-post contrast, diagnostic accuracy improved significantly, with near-perfect AUC values. Kappa values indicated moderate to substantial agreement between radiological assessments and clinical diagnosis. The combined sequences achieved 100% sensitivity and specificity for tract visualization.

CONCLUSION

STIR imaging presents promise as a singular diagnostic tool for perianal fistulas, especially when combined with T1-post contrast sequences. While offering potential clinical diagnosis simplifications, further studies are warranted to validate its utility and ensure comprehensive diagnostic accuracy.

Contemporary management of anorectal fistula

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

The Role of Magnetic Resonance Imaging in Pre-operative Assessment of Anorectal Fistula With Surgical Correlation

Background Anorectal fistulas are chronic inflammations of peri-anal tissues that form a connection between the perineal skin and the anal canal. Accurate preoperative evaluation of the main fistula's trajectory and pelvic tissues is essential for effective surgical treatment of anal fistulas. The inability to detect concealed lesions may result in the recurrence of fistulas and the conversion of a simple fistula into a complex fistula. Magnetic resonance imaging (MRI) imaging can detect concealed pathways and abscesses, thereby exposing the intricate connection between the fistula and anal-sphincter complex. This data serves as a roadmap for making surgical decisions, thereby reducing the likelihood of illness recurrence and complications after surgery. Aim To evaluate the role of MRI in pre-operative assessment of an anorectal fistula, compare its findings with surgical results. Materials and methods The research was conducted at the Radiology Department, Apollo Hospital, Hyderabad. It was a prospective observational study. IBM SPSS Statistics for Windows, Version 17 (released 2008; IBM Corp., Armonk, New York, United States) was utilized for data analysis. The mean and standard deviation were computed. We further applied appropriate statistical tests to determine the significance of MRI features with pre-operative findings. Results MRI accurately detects features like abscesses (sensitivity-100%, specificity-97.06%), secondary tracts of the fistula (sensitivity-93.55%, specificity-94.12%), horseshoe appearance, and supralevator extension (sensitivity-100%, specificity-97.50%, and 97.62%, respectively). Conclusion When comparing our results with intraoperative findings, MRI showed high sensitivity and specificity in detecting abscesses, secondary tracts, horseshoe appearances, and supralevator extensions. Our findings suggest that MRI can offer anatomical and pathological information for the pre-operative care and surgical planning of perianal fistulas.

Fistula-in-Ano with Broomsticks: An Unusual Etiology

ABSTRACT

Fistula-in-ano is caused by idiopathic infection of the cryptoglands located in the anal intersphincteric plane when the resultant cryptoglandular abscess drains internally and externally. It is a common surgical disease that responds well to surgical intervention. In cases of recurrent non-healing fistula-in-ano, an underlying cause should be suspected and searched for. We present a 29-year-old man who had recurrent complex fistula-in-ano caused by broomsticks of an unknown source. Fistulotomy, tactile wound exploration, extraction of the broomsticks, and wound debridement were done. The wound healed well by secondary intention. Few cases of recurrent complex fistula-in-ano had been reported in the literature. However, this is the first time to the best of our knowledge that broomsticks causing non-healing, complex fistula-in-ano that is being reported. We suggest the use of a bending machine instead of mashing broom bunch in the preparation of Ewedu soup which is a delicacy for the Yoruba tribe in Nigeria to eliminate the chances of inadvertent ingestion of broomsticks when eating Ewedu soup.

Typical MR features and interpretation of perianal fistulas in patients with Crohn's disease

Perianal fistulas in Crohn's disease (CD) are a poor prognostic phenotype requiring a combination of medical and surgical management. Perianal fistulas in CD are characterized by more complex and multi-branched fistulas, association with skin tags, and frequent presence of proctitis. A comprehensive approach with clinical examination, endoscopic and MR assessment is required, and in particular, MR interpretation provides detailed information on the type of fistula with its internal component and activity, secondary tracts and extension, internal, external openings, associated abscess, and presence of proctitis. Structured reporting of these items would be recommended for further discussion and management planning both at initial diagnosis and for disease monitoring during treatment follow-up. Management strategy would be individualized for each patient, and control of luminal disease activity could be an important determinant in the selection of treatment options. In this review, we provide an overview of the MRI evaluation of perianal fistulas in CD with a proposed structured MR report.

A case report of anal fistula-associated mucinous adenocarcinoma developing 3 years after treatment of perianal abscess

BACKGROUND

A long-standing (over 10 years) anal fistula is considered a fundamental cause of fistula-associated mucinous adenocarcinoma (FAMC). Perianal abscesses and anal fistulas are two sequential phases of the same anorectal infectious process. We experienced a case of FAMC which developed 3 years after the treatment of a perianal abscess.

CASE PRESENTATION

A 68-year-old woman was admitted to our hospital because of progressive anal pain and a palpable tumor. She had a history of undergoing a drainage operation for a perianal abscess 3 years previously. A 15 × 15-mm tumor at the former drainage site was identified; transanal ultrasonography showed an intersphincteric fistula connecting to the tumor. A biopsy taken from the tumor demonstrated mucinous adenocarcinoma; the tumor was diagnosed as FAMC. Laparoscopic abdominoperineal resection was performed. Histopathology showed highly dysplastic cells lining the lumen of the anal fistula and poorly differentiated mucinous adenocarcinoma proliferating in the dermis and epidermis in the distal aspect of the fistula.

CONCLUSIONS

FAMC can develop within fewer than 3 years after the development of a perianal abscess and anal fistula.

Management of Perianal Fistulizing Crohn's Disease

Perianal fistulizing Crohn's disease (CD) represents a severe phenotype of CD that is associated with significant morbidity and reduction in quality of life. Perianal fistulizing CD is caused by a complex interplay of genetic predisposition, immune dysregulation, gut dysbiosis, and various unknown physiological and mechanical factors. A multidisciplinary approach is hence required for optimal management . A detailed anatomical description and classification of perianal fistula, including comprehensive clinical, endoscopic, and radiological diagnostic workup, is an important prerequisite to treatment. For simple perianal fistulas, use of antibiotics and immunomodulators, with or without fistulotomy, are appropriate measures. The medical management of complex perianal fistula, on the other hand, requires adequate control of infection before initiation of therapy with immunomodulators. In active complex perianal fistula, anti-tumor necrosis factors remain the most accepted therapy, with concomitant use of antibiotics or immunomodulators enhancing the efficacy. For patients refractory to anti-tumor necrosis factors, treatment with anti-integrins, anti-interleukins, and small molecules is being evaluated. Mesenchymal stem cells, hyperbaric oxygen therapy, and exclusive enteral nutrition have also been investigated as adjunct therapies. Despite the expansion of the medical armamentarium, a large proportion of the patients require surgical interventions. In this review, we provide an up-to-date overview of the pathophysiology, clinical presentation, diagnosis, and medical management of perianal fistulizing CD. A brief overview of the surgical management of perianal fistulizing CD is also provided.

Imaging the levator ani and the puborectalis muscle: implications in understanding regional anatomy, physiology and pathology

Purpose:To review the findings of recent dynamic imaging of the levator ani muscle in order to explain its function during defecation. Historical anatomical studies have suggested that the levator ani initiates defecation by lifting the anal canal, with conventional dissections and static radiologic imagery having been equated with manometry and electromyography.Materials and methods:An analysis of the literature was made concerning the chronological development of imaging modalities specifically designed to assess pelvic floor dynamics. Comparisons are made between imaging and electromyographic data at rest and during provocative manoeuvres including squeeze and strain.Results:The puborectalis muscle is shown distinctly separate from the levator ani and the deep external anal sphincter. In contrast to conventional teaching that the levator ani initiates defecation by lifting the anus, dynamic illustration defecography (DID) has confirmed that the abdominal musculature and the diaphragm instigate defecation with the transverse and vertical component portions of the levator ani resulting in descent of the anus. Current imaging has shown a tendinous peripheral structure to the termination of the conjoint longitudinal muscle, clarifying the anatomy of the perianal spaces. Planar oXy defecography has established patterns of movement of the anorectal junction that separate controls from those presenting with descending perineum syndrome or with anismus (paradoxical puborectalis spasm).Conclusions:Dynamic imaging of the pelvic floor (now mostly with MR proctography) has clarified the integral role of the levator ani during defecation. Rather than lifting the rectum, the muscle ensures descent of the anal canal.

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

Background and Aims

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

Methods

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

Results

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

Conclusion

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

[Perianal Fistula: An Overview]

Perianal fistula is a common inflammatory condition in the general population and affects the area around the anal canal. Although most cases are benign, they cause serious morbidity and require surgical treatment due to a high risk of recurrence. MR imaging is a gold standard technique for the evaluation of perianal fistulas and provides accurate information on the anatomy of the anal canal, its relationship to the anal sphincter complex, accurate identification of secondary tracts or abscesses, and reporting associated complications. MR imaging can help monitor treatment effects and determine treatment methods. Crohn's disease-related fistulas often require medical rather than surgical treatment. The radiologist is required to know the anatomy and MR imaging findings of the perianal fistula to present an accurate diagnosis to the clinician.

Magnetic resonance imaging in the workup of patients with perianal fistulas

Background

Perianal sepsis and fistulas are common lesions. Fistula-in-ano is a tedious problem because of high recurrence rates and severe unexpected complications postoperatively. Many imaging modalities are used to evaluate this area. Magnetic resonance imaging (MRI) has been considered the gold standard procedure for perianal fistula assessment, i.e., it provides the surgeon with an accurate roadmap to select the best surgical approach, determines the extent of sphincter division, and estimates the risk of postoperative incontinence. We carried out a prospective diagnostic accuracy study involving 50 patients (mean age, 42.44 years) with perianal fistulas who underwent pelvic MRI with a 1.5 Tesla scanner using multiple sequences, including diffusion and post-contrast series that were either local or systemic. This study aimed to evaluate the diagnostic validity of pelvic MRI/MR fistulogram in perianal fistula assessment, identify perianal fistula-associated findings by MRI, and optimize the MRI technique with maximum technical safety.

Results

Intersphincteric fistulas were the most common type of perianal fistula observed based on Parks’ classification. Intersphincteric, trans-sphincteric, extrasphincteric, and suprasphincteric fistulas were found in 30 (60%), 12 (24%), 4 (8%), and 4 (8%) patients, respectively. According to St. James’ classification, 21 (42%), 9 (18%), 8 (16%), 4 (8%), and 8 (16%) patients had perianal fistula grades I, II, III, IV, and V, respectively. The combination of variable MR sequences and MR fistulogram increased the diagnostic validity of MRI examinations. Our results correlated with surgical results (reference standard) with perfect interobserver reliability.

Conclusions

Of all imaging modalities, MRI has become a prerequisite for a successful surgery of a perianal fistula. MRI can identify: (a) fistula morphological details, (b) the relationship between the fistulous tract and the anal sphincter, (c) fistula wound healing, (d) an active versus chronic scarred fistula, (e) postoperative stigmata, and (f) a perianal fistula from its mimics. MRI with variable sequences and MRI fistulogram are successful combinations that increase diagnostic efficiency with technical safety by avoiding both ionizing radiation and systemic gadolinium.

Surgery of Simple and Complex Anal Fistulae in Adults: A Review of the Literature for Optimal Surgical Outcomes

Anal fistulas are common anorectal conditions, and surgery is the primary treatment option. In the last 20 years of literature, there exist a large number of surgical procedures, especially for the treatment of complex anal fistulas, as they present more recurrences and continence problems than simple anal fistulas. To date, there are no guidelines for choosing the best technique. We conducted a recent literature review, mainly the last 20 years, based on the PubMed and Google Scholar medical databases, with the goal of identifying the surgical procedures with the highest success rates, lowest recurrence rates, and best safety profiles. Clinical trials, retrospective studies, review articles, comparative studies, recent systematic reviews, and meta-analyses for various surgical techniques, as well as the latest guidelines of the American Society of Colon and Rectal Surgeons, the Association of Coloproctology of Great Britain and Ireland, and the German S3 guidelines on simple and complex fistulas were reviewed. According to the literature, there is no recommendation for the optimal surgical technique. The etiology, complexity, and many other factors affect the outcome. In simple intersphincteric anal fistulas, fistulotomy is the procedure of choice. In simple low transsphincteric fistulas, the patient's selection is crucial in order to perform a safe fistulotomy or another sphincter-saving technique. The healing rate in simple anal fistulas is higher than 95% with low recurrence and without significant postoperative complications. In complex anal fistulas, only sphincter-saving techniques should be used; the optimal outcomes are obtained by the ligation of the intersphincteric fistulous tract (LIFT) and rectal advancement flaps. Those techniques assure high healing rates of 60-90%. The novel technique of the transanal opening of the intersphincteric space (TROPIS) is under evaluation. The novel sphincter-saving techniques of fistula laser closure (FiLac) and video-assisted anal fistula treatment (VAAFT) are safe, with reported healing rates ranging from 65% to 90%. Surgeons should be familiar with all sphincter-saving techniques in order to face the variability of the fistulas-in-ano. Currently, there is no universally superior technique that can treat all fistulas.

Crohn's Disease-Associated and Cryptoglandular Fistulas: Differences and Similarities

Perianal fistulas are defined as pathological connections between the anorectal canal and the perianal skin. Most perianal fistulas are cryptoglandular fistulas, which are thought to originate from infected anal glands. The remainder of the fistulas mainly arises as complications of Crohn's disease (CD), trauma, or as a result of malignancies. Fistulas in CD are considered as a consequence of a chronic and transmural inflammatory process in the distal bowel and can, in some cases, even precede the diagnosis of CD. Although both cryptoglandular and CD-associated fistulas might look similar macroscopically, they differ considerably in their complexity, treatment options, and healing rate. Therefore, it is of crucial importance to differentiate between these two types of fistulas. In this review, the differences between CD-associated and cryptoglandular perianal fistulas in epidemiology, pathogenesis, and clinical management are discussed. Finally, a flow chart is provided for physicians to guide them when dealing with patients displaying their first episode of perianal fistulas.

Ligation of Intersphincteric Fistulous Tract vs Endorectal Advancement Flap for High-Type Fistula in Ano: A Randomized Controlled Trial

BACKGROUND

This study aimed to compare the postoperative outcomes and success rate of the endorectal advancement flap and ligation of intersphincteric fistulous tract (LIFT) in high-type fistula in ano.

STUDY DESIGN

This randomized control trial included patients with high-type fistula in ano of cryptoglandular origin. The primary endpoint was complete fistula healing at the end of 6 months. However, the patients were followed up for 2 years. Other parameters studied were perioperative complications, duration of surgery, postoperative pain, hospital stay in hours, continence, and quality of life at 6 months.

RESULTS

A total of 84 patients were recruited (42 in each group). The healing rate in the LIFT arm was better than that in the endorectal advancement flap arm (76.2.% vs 54.7%, p = 0.039). Four patients in the endorectal advancement flap group and two in the LIFT group had flatus incontinence at the end of 6 months, but all were continent at 2 years. At the end of the first week, the Visual Analog Scale score and quality of life at 6 months were better in the LIFT arm (3.7 ± 1.16 vs 4.7 ± 0.81 and 0.7 vs 0.6, p < 0.05). The mean duration of surgery was significantly less in the LIFT group (46.43 ± 9.32 vs 89.29 ± 10.90 minutes). None had any postoperative complications, and >80% were discharged within 24 hours.

CONCLUSIONS

The shorter operative duration, better quality of life at 6 months, and higher healing rate make LIFT a superior treatment option for high fistula in ano. However, studies with a large sample size will be needed to verify these results.

A Case of Human Mpox with Isolated Perianal Ulcers Development in Convalescent Phase

A 35-year-old man who returned from Germany developed fever, generalized pain, severe anal pain, and generalized skin rash, confirmed to be monkeypox (mpox). While he was previously confirmed to be human immunodeficiency virus infected, antiretroviral therapy ensured his immunocompetence. The mpox-related prodromal symptoms disappeared before isolation, and subsequent several vesicular skin lesions healed after admission. While moderate anal pain persisted for a few days, it improved during hospitalization. The mpox virus was no longer detected in samples taken from the upper respiratory tract and skin by polymerase chain reaction upon admission. However, isolated perianal ulcers developed after admission without any other mpox-related symptoms or signs, and a viable mpox virus was isolated from these ulcers. Considering the novel feature of asynchronous mucocutaneous lesion development in the current mpox epidemic, meticulous physical examination of newly developing lesions, especially in anogenital areas, should be performed during mpox management.

MRI of Recurrent Fistula-in-Ano: Is it Different from Treatment-Naïve Fistula-in-Ano and How Does it Correlate with Anal Sphincter Morphology?

Objectives  The main aim of this study was to compare magnetic resonance imaging (MRI) findings of recurrent and treatment-naïve fistula-in-ano and to correlate imaging findings with anal sphincter morphology in recurrent fistula-in-ano. Methods  This is a retrospective study of adult patients who underwent MRI for suspected fistula-in-ano in 2018. After excluding patients with alternative diagnosis, patients were stratified into recurrent ( n  = 103) and treatment-naïve ( n  = 106) fistula-in-ano groups. Two blinded radiologists reread MRI scans in consensus for fistula characteristics and anal sphincter morphology. We compared imaging features of recurrent and treatment-naïve fistula-in-ano, assessed the incidence of anal sphincter scarring among patients with recurrent fistula-in-ano, and studied its association with fistula features. Results  Two-hundred nine patients (187 males) with mean age of 40.6 (standard deviation: 12.2) years were included. Trans-sphincteric, inter-sphincteric, extra-sphincteric, and supra-sphincteric fistula-in-ano were seen in 63.6, 33, 2.9, and 0.5%, respectively. There were secondary tracts, supralevator extension, and secondary cause for fistula in 49.3, 12.9, and 14.8%, respectively. There was no difference between the fistula features of recurrent and treatment-naïve fistula-in-ano, except for significantly fewer external openings among recurrent fistula-in-ano ( p  = 0.005). Among patients with recurrent fistula-in-ano, MRI detected anal sphincter defect/scarring was seen in 53.4% ( n  = 55) and was significantly associated with posterior fistula-in-ano ( p  = 0.031), collections and/or supralevator extension ( p  = 0.010), and secondary tracts ( p  = 0.015). Conclusion  Fistula features of recurrent and treatment-naïve patients were mostly similar. There was high incidence (53.4%) of MRI-identified anal sphincter scarring/defect among recurrent fistula-in-ano, which was significantly associated with posterior fistula, collections, supra or translevator extension, and secondary tracts. Key Points MRI-identified anal sphincter scarring is very common among patients with recurrent fistula-in-ano and seen in more than half of them.There was significantly higher incidence of sphincter scarring among patients who had posterior fistula, collections, supralevator/translevator extension, and secondary tracts.

Acute supralevator abscess: the little we know

INTRODUCTION

Acute supralevator abscess (SLA) is an uncommon and complicated form of anorectal sepsis. Its correct management is crucial to avoid complex iatrogenic fistula formation. A comprehensive review of the literature was conducted to determine the incidence of SLA and the surgical outcome with particular reference to the direction of drainage.

METHODS

A search of Medline, PubMed and the Cochrane Library was performed to identify all studies reporting surgical drainage of SLA.

FINDINGS

A total of 19 studies were identified, including 563 patients. The only two prospective studies reported an incidence of SLA of 10% and 3% in 68 and 100 patients, respectively, with anorectal sepsis. In 17 retrospective studies, the incidence ranged from 0% to 28%. Magnetic resonance imaging (MRI) was performed routinely in only one study. The surgical anatomical classification of the abscess was described in six studies diagnosed at surgery. The direction of surgical drainage whether 'inwards' (into the lumen) or 'outwards' (into the ischioanal fossa) was stated in only six studies. In two of these, the direction of drainage was contradictory to the recommendation made by Parks et al. Recurrent sepsis was reported in eight studies and ranged from 0% to 53%.

CONCLUSIONS

Detailed and prospective data on acute SLA are lacking. Its real incidence is unclear and it is not possible to analyse surgical outcomes conclusively according to different direction of drainage. The routine use of MRI in complicated anorectal sepsis would specify the surgical anatomy of SLA before any drainage is carried out.

Colonic Acquired Fistulae: The Potential of CT Colonography

The diagnosis of colonic fistulae is crucial in defining the best therapeutic approach. Fistulae can be suspected from clinical history or specific symptoms, but imaging plays a key role in confirming the diagnosis. Previous studies described conventional studies with barium as methods of choice for the diagnosis; more recently intestinal ultrasound, CT and MR have been considered promising tests. CT Colonography is the best radiologic test to evaluate the colon, but only few case reports described its role in this setting. Aim of this paper is to highlight the potentials of CT colonography in evaluating patients with suspected colonic fistulae.

Fistula in Ano-A 2-Year Prevalence Study on North Indian Rural Population

Perianal fistula (PF) is a common inflammatory condition affecting the perianal region including the sphincter muscles, ischioanal fossae, and the perianal skin. It is notorious to recur and, as a result, causes significant morbidity in both urban and rural population. Magnetic resonance imaging (MRI) has revolutionized imaging in PFs as it provides excellent anatomical visualization of the fistulous tracts, their origin, course, number, chronicity, opening in the external and internal anal sphincter, length of sphincter, evidence of active disease and abscess formation along the tract. It is also very useful in presurgical mapping and reduce the chances of recurrence. Most of the studies done on PFs are based on the urban population. Rural population have a completely different lifestyle which makes them susceptible to various diseases, less prevalent in the urban population. Hence, the purpose of this article is to find the prevalence of different grades in North Indian rural region close to the NCR (National Capital Region). In the study including 98 patients, the maximum number of patients were classified into grade 1 and grade 4 by MRI according to St. James' University Hospital MRI classification. This is the second reported study on prevalence of different grades of PFs in rural population in India. The higher prevalence of grade 4 PFs in our study might be secondary to illiteracy, social stigma, poor hygiene, or higher recurrence rate. Closely understanding the difference in dynamics of urban and rural population, our goal of the study is to determine the prevalence of different grades of PFs in the rural population. We also aim to familiarize physicians, radiologists, and surgeons with the MRI evaluation and grading of PF to help in presurgical mapping and thus, reducing the chances of recurrence. We also recommend further studies to evaluate psycho-social factors as a barrier in seeking early medical care in rural population.

Development and Validation of a Pediatric MRI-Based Perianal Crohn Disease (PEMPAC) Index-A Report from the ImageKids Study

BACKGROUND

As part of the prospective multicenter ImageKids study, we aimed to develop and validate the pediatric MRI-based perianal Crohn disease (PEMPAC) index.

METHODS

Children with Crohn disease with any clinical perianal findings underwent pelvic magnetic resonance imaging at 21 sites globally. The site radiologist and 2 central radiologists provided a radiologist global assessment (RGA) on a 100 mm visual analog scale and scored the items selected by a Delphi group of 35 international radiologists and a review of the literature. Two weighted multivariable statistical models were constructed against the RGA.

RESULTS

Eighty children underwent 95 pelvic magnetic resonance imaging scans; 64 were used for derivation and 31 for validation. The following items were included: fistula number, location, length and T2 hyperintensity; abscesses; rectal wall involvement; and fistula branching. The last 2 items had negative beta scores and thus were excluded in a contending basic model. In the validation cohort, the full and the basic models had the same strong correlation with the RGA (r = 0.75; P < 0.01) and with the adult Van Assche index (VAI; r = 0.93 and 0.92; P < 0.001). The correlation of the VAI with the RGA was similar (r = 0.77; P < 0.01). The 2 models and the VAI had a similar ability to differentiate remission from active disease (area under the receiver operating characteristic curve, 0.91-0.94). The PEMPAC index had good responsiveness to change (area under the receiver operating characteristic curve, 0.89; 95% confidence interval, 0.69-1.00).

CONCLUSIONS

Using a blended judgmental and mathematical approach, we developed and validated an index for quantifying the severity of perianal disease in children with CD. The adult VAI may also be used with confidence in children.

Anorectal pathology in the HIV population: a guide for radiologists

Patients with human immunodeficiency virus (HIV) can present with a wide range of different acute and chronic pathologies. Anorectal conditions are particularly common in this unique patient population, including pathologies, such as proctitis, anorectal abscess, anorectal fistula, and anal squamous cell carcinoma. The radiologist plays a critical role in the assessment of these common forms of anorectal disease, as these conditions can present with various findings on imaging assessment. Pelvic CT, MRI, and FDG-PET/CT are among the most common modalities used for assessment of anorectal disease in the HIV patient population. Knowledge of the fundamental clinical and imaging findings associated with these pathologies in HIV patients is critical for radiologists.

Role of Transcutaneous Perianal Ultrasonography in Evaluation of Perianal Fistulae with MRI Correlation

Purpose: The aim of this study was to evaluate the role of transcutaneous perianal ultrasonography (TPUS) in patients with perianal fistula and to correlate the findings with magnetic resonance imaging (MRI) as gold standard.

Materials and Methods: This prospective study included patients who presented with suspicion of perianal fistula. After clinical examination, TPUS and MRI of perianal region were performed on each of them. Clockwise position of internal opening of the fistula was described. The entire length of the tract was evaluated up to the external opening. Also, any ramifications along the primary tract were described. Parks et al and St James's University Hospital MR Imaging Classification of Perianal Fistulas were used for classifying the fistulas.

Results: Out of total 37 patients, the most common age group of presenting individuals was 45 to 60 years with male to female ratio of 6.4:1. There was excellent agreement between TPUS and MRI for detecting primary fistulous tract with kappa correlation coefficient of 1. The kappa correlation coefficient for detecting secondary fistulous tracts and abscess on TPUS and MRI was 0.839 and 0.937 showing excellent agreement. Moderate agreement was seen with kappa correlation coefficient of 0.839 in the detection of internal opening on TPUS and MRI.

Conclusion: TPUS showed promising results in diagnosis and classification of perianal fistulae with MRI as gold standard. A wide availability, cost-effectiveness, and better tolerability of TPUS can make it an imaging modality of first choice for evaluating perianal fistulae.

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 Multi-Disciplinary Approach to Perianal Fistulizing Crohn's Disease

Perianal fistulizing Crohn's disease represents a severe phenotype associated with significant morbidity. Patients with perianal fistulizing disease are more likely to have a severe disease course and have significant reductions in quality of life. Moreover, these patients are at risk for the development of distal rectal and anal cancers. Given the complexity and severity of this patient group, the management of perianal Crohn's disease must be undertaken by a multidisciplinary team. The gastroenterologist and colorectal surgeon play a critical role in the diagnosis and management of perianal fistulizing disease. An examination under anesthesia provides critical information and is an essential part of the work-up of complex perianal fistulas. The radiologist also plays a central role in characterizing anatomy and assessing response to treatment. Several imaging modalities are available for these patients with magnetic resonance imaging as the imaging modality of choice. Perianal disease developing after ileal pouch-anal anastomosis represents a particularly challenging form of fistulizing disease and requires a multidisciplinary clinical and radiologic approach to differentiate surgical complications from recurrent Crohn's disease.

A Novel Modification of the Endorectal Advancement Flap for Complex Anal Fistulas: Surgical Technique and Outcomes

Objective

A modification of the endorectal advancement flap (EAF) procedure is described with outcomes in a single-center, large retrospective cohort study.

Summary of background data

Fistula-in-ano is a common problem encountered by surgeons that can be classified as either simple or complex. Complex fistulas (CFs) cause higher morbidity and are much more challenging to treat. Although numerous treatment options are available for CF, none are proven to be 100% effective. The endorectal advancement flap (EAF) procedure was developed as an alternative to conventional surgical treatments for CF.

Methods

Charts were reviewed of patients with CF who underwent EAF between 2004 and 2019. The conventional EAF procedure was modified by performing transverse imbrication of the internal sphincter over the internal fistula opening. The incidence of new-onset fecal incontinence and recurrence were analyzed at the last available date of in-person follow-up.

Results

With a median follow-up of 6.6 months (range, 3.3–24 months), 99 patients with CFs underwent a modified EAF. Of these, 93% (92 of 99) had resolution of fistula without adverse outcomes, 7% (7 of 99) experienced recurrence, and 1% (1 of 99) experienced new-onset fecal incontinence. Systemic steroid or immunomodulatory therapy use (P = 0.001) and patients with diagnosed inflammatory bowel disease (P &lt; 0.0001) were associated with increased rate of recurrence.

Conclusions

EAF with transverse imbrication of the internal opening using interrupted, absorbable suture is an effective technique to treat complex or recurrent anal fistulas. It is associated with a low risk of recurrence (7%) and fecal incontinence (1%) and is a valid treatment option for CFs.

CT and MRI Evaluations in Crohn's Complications: A Guide for the Radiologist

Inflammatory bowel diseases (IBD) are a group of chronic inflammatory intestinal conditions with unknown etiology. Crohn's disease (CD) and ulcerative colitis (UC) are the two main types of IBD and they have some interchangeable and some different clinical and pathological characteristics. When diagnosis is performed for the first time, the majority of CD patients have a predominant inflammatory condition. As the disease progresses most patients experience the development of complications, such as abscesses, fistulas, perforation, strictures, and others. Both computed tomography (CT) and Magnetic Resonance Imaging (MRI) allow great view of the whole length of the intestinal tract together with the eventual extra-and intra-intestinal complications. MR enterography (MRE) and CT enterography (CTE), performed after oral administrations of contrast medium, have similar diagnostic accuracy for the diagnosis of CD and its complications. Even though CT is still the most familiar diagnostic technique used for studying CD worldwide, MRE have several important benefits that are leading to rapid increase in its employment in the last years. In particular, MRE allows a superior soft tissue contrast resolution compared to CT, offering a better visualization of bowel wall and its inflammatory and fibrotic characteristics. Moreover, Pelvic Magnetic Resonance is the principal technique in patients with perianal disease due to its ability of providing precise and fine detail images of the sphincter complex, which are crucial for evaluating pelvic disease. In this paper we describe common and uncommon complications in patients with CD, and explain how to identify their findings in CT and MR exams.

Perianal Imaging in Crohn Disease: Current Status With a Focus on MRI, From the AJR Special Series on Imaging of Inflammation

Fistulizing perianal disease is a frequent, chronic, and often debilitating manifestation of Crohn disease (CD) in adults and children, which in the past was relatively refractory to treatment. The advent of biologic agents such as anti-tumor necrosis factor-α and cellular therapies, used in conjunction with a range of surgical interventions, has greatly improved disease outcomes, although complete remission can still be elusive. This review considers current perianal imaging options, specifically pelvic MRI and endoanal and transperineal ultrasound, and their roles in diagnosis, management, and assessment of treatment response. Pelvic MRI is the first line technique for imaging of perianal CD given the complexity of fistulas encountered in CD. MRI technical acquisition parameters for adults and children and an approach to MRI interpretation and reporting are provided. Anatomic classification systems for fistulising perianal disease are presented. We also explore the history, current landscape, and future developments of MRI features of perianal disease as imaging biomarkers to quantify activity and severity, and consider CD MRI-based inflammatory activity scores. We discuss the reliability and validation of a number of indices (including PEMPAC, MAGNIFI-CD, mVAI, and Van Assche Index), their potential to quantify treatment response, and possible prognostic capabilities.

The new pathways of spread of anal fistula and the pivotal role of MRI in discovering them

Conventionally, in the pathophysiology of anal fistulas, there is only one space considered significant for the spread of pus in the sphincter complex: the intersphincteric space. However, with increasing experience in the high-resolution MRI, and more focus being given on managing fistulas through the intersphincteric space, two additional pathways of fistula spread have been identified. First is a newly described space labelled as the outer-sphincteric space. Second is a known anatomical space (inner intersphincteric space), but this space was considered as irrelevant from the point of view of fistula spread. The conventional intersphincteric space is present in between these two spaces and is referred as 'middle intersphincteric space' in this paper. These three distinct spaces have significant clinical implications as the pattern of spread of pus is quite different in each space, and the management also differs for fistula tract in each of these spaces.

Magnetic Resonance Imaging of Perianal Fistulas in Clinically Symptomatic Patients and the Correlation Among Plain, Contrast, and Post Jelly MRI Fistulography

Objectives To evaluate different types of perianal fistulas and their complications on magnetic resonance imaging (MRI) and to compare plain, contrast, and jelly magnetic resonance fistulography findings.

Materials and Methods This prospective study was performed in 30 patients who presented with perianal pus discharge or external fistulous opening. Magnetic resonance imaging of the perianal region before and after giving intravenous contrast and after injecting jelly through a percutaneous opening was performed on a 3T scanner and the results were correlated.

Results The mean age of the patients was 40.13 ± 13.88 years (range 19–75 years). The male to female ratio was 14:1. The most common type of fistula was St. James classification type I, which was seen in 13 patients (43%), followed by type IV in 30%, type III in 16%, type II in 6.66%, and type V in 3.33% of the patients. Using agreement analysis, we compared the number of primary and secondary tracts, internal openings, and horseshoe tracts and found a significant agreement between plain and post Jelly MRI fistulography (kappa statistic close to 1). When comparing plain and contrast MRI, there was significant agreement in the primary and secondary tracts, while statistically insignificant results were obtained (p > 0.05) for the horseshoe tract and internal openings. Contrast injection was helpful in 7 subjects (23.3%) as peripheral enhancement of abscesses were better delineated.

Conclusion Magnetic resonance imaging is the one stop diagnostic modality for perianal fistulas. Acquisition of axial (Ax) T2, axial T2 FS, coronal T2 and coronal T2 FS sequences without administering intravenous contrast or jelly is usually sufficient for the diagnosis of fistulas and their complications.

Getting the most out of MRI in perianal fistula: update on surgical techniques and radiological features that define surgical options

Perianal fistulas affect approximately 2 in 10,000 people, causing symptoms such as pain and discharge, which can have a debilitating effect on a patient's quality of life. Surgical treatment, which can offer a potential cure or palliation of symptoms, must be considered carefully in cases with extensive sphincter involvement. In complex cases, the use of preoperative magnetic resonance imaging (MRI) can help to determine the best course of operative action. This review describes common and contemporary surgical procedures for perianal fistula, highlighting technical features, as well as important surgical considerations associated with each method and how these can be assessed radiologically. We focus on the anatomical features and MRI findings that take procedural elements into account and help determine the most appropriate method of treatment. The aim of this article is to provide a basis for informed and focused discussion between surgeons and radiologists to ensure the most appropriate procedure is selected for each case, with the ultimate aim of obtaining the most favourable outcomes for patients.

Role of Diffusion-Weighted Imaging in the Evaluation of Perianal Fistulae

Background  Magnetic resonance imaging (MRI) is the imaging modality of choice for evaluating perianal fistulae, due to its ability to show the relationship of perianal fistulae with anal sphincters, fistula extensions, secondary ramifications and associated complications.

Aim  To evaluate the role of diffusion-weighted MRI in the evaluation of perianal fistulae.

Settings and Design  A hospital-based cross-sectional study.

Materials and Methods  The study group composed of 47 patients of perianal fistula. MRI with diffusion-weighted imaging (DWI) was performed with Philips 0.5 T Ingenia scanner. DWI with different b -values ( b = 50, b = 400, and b = 800 smm ² ) were obtained. The MRI findings were correlated with local clinical examination and or surgical findings.

Statistical Analysis Used  Chi-square test, independent samples t -test, and receiver operating characteristic curve analysis.

Result  Fifty-nine perianal fistulas in 47 patients were included in the study sample. The visibility of perianal fistula on DWI was less than T2-weighted (T2W) and combined DWI-T2W images. Distinctly visualized (visibility score 2) perianal fistulas were observed in 47 fistulas (79.6%) on DWI, 54 (91.5%) on T2W, and 58 (98.3%) on DWI-T2W images. The mean of apparent diffusion coefficient (ADC) values of active fistula was 0.972 ± 0.127 [SD] 10 ⁻³ mm ² /s and inactive was 1.232 ± 0.185 [SD] 10 ⁻³ mm ² /s with a significant difference ( p -value < 0.0005). A cut-off mean ADC value of 1.105 × 10 ⁻³ mm ² /s was used to differentiate active from the inactive fistula with a sensitivity of 87.5% and specificity of 73.3%.

Conclusion  Combined DWI-T2W evaluation had a better performance in the detection of fistula than DWI or T2W alone. DWI with mean ADC calculation had a good performance in differentiating active from the inactive fistulas.

Current concepts in the pathogenesis of cryptoglandular perianal fistula

Cryptoglandular perianal fistula is a common benign anorectal disorder that is managed mainly with surgery. A fistula is typically defined as a pathological communication between two epithelialized surfaces. More specifically, perianal fistula manifests as an abnormal tract between the anorectal canal and the perianal skin. Perianal fistulas are often characterized by significantly decreased patient quality of life. The cryptoglandular theory of perianal fistulas suggests their development from the proctodeal glands, which originate from the intersphincteric plane and perforate the internal sphincter with their ducts. Involvement of proctodeal glands in the inflammatory process could play a primary role in the formation of cryptoglandular perianal fistula. The objective of this narrative review was to investigate the current knowledge of the pathogenesis of cryptoglandular perianal fistula with the specific aims of characterizing the potential role of proinflammatory factors responsible for the development of chronic inflammation. Further studies are crucial to improve the therapeutic management of cryptoglandular perianal fistulas.

MRI of Perianal Crohn Disease: Technique and Interpretation

ABSTRACT

Magnetic resonance imaging (MRI) has emerged as the imaging method of choice for evaluation of perianal fistulizing disease. As treatment of Crohn disease and associated perianal fistulas has evolved to include a combination of systemic treatments and surgical interventions, perianal MRI provides critical information to guide treatment selection and timing. Radiologists need to be familiar with the normal regional anatomy to accurately describe perianal fistulas and any associated complications which can then be used to classify fistulas based on several available classification systems. Following treatment, MRI can provide information that suggests treatment success or failure. We propose a perianal fistula reporting template that includes the necessary information to convey fistula complexity, guide treatment, and evaluate treatment response. This review article will also discuss the postoperative appearance of many treatments currently used for management of perianal fistulizing disease and some associated complications.

Lessons learned from an audit of 1250 anal fistula patients operated at a single center: A retrospective review

BACKGROUND

A complex anal fistula is a challenging disease to manage.

AIM

To review the experience and insights gained in treating a large cohort of patients at an exclusive fistula center.

METHODS

Anal fistulas operated on by a single surgeon over 14 years were analyzed. Preoperative magnetic resonance imaging was done in all patients. Four procedures were performed: fistulotomy; two novel sphincter-saving procedures, proximal superficial cauterization of the internal opening and regular emptying and curettage of fistula tracts (PERFACT) and transanal opening of intersphincteric space (TROPIS), and anal fistula plug. PERFACT was initiated before TROPIS. As per the institutional GFRI algorithm, fistulotomy was done in simple fistulas, and TROPIS was done in complex fistulas. Fistulas with associated abscesses were treated by definitive surgery. Incontinence was evaluated objectively by Vaizey incontinence scores.

RESULTS

A total of 1351 anal fistula operations were performed in 1250 patients. The overall fistula healing rate was 19.4% in anal fistula plug (n = 56), 50.3% in PERFACT (n = 175), 86% in TROPIS (n = 408), and 98.6% in fistulotomy (n = 611) patients. Continence did not change significantly after surgery in any group. As per the new algorithm, 1019 patients were operated with either the fistulotomy or TROPIS procedure. The overall success rate was 93.5% in those patients. In a subgroup analysis, the overall healing rate in supralevator, horseshoe, and fistulas with an associated abscess was 82%, 85.8%, and 90.6%, respectively. The 90.6% healing rate in fistulas with an associated abscess was comparable to that of fistulas with no abscess (94.5%, P = 0.057, not significant).

CONCLUSION

Fistulotomy had a high 98.6% healing rate in simple fistulas without deterioration of continence if the patient selection was done judiciously. The sphincter-sparing procedure, TROPIS, was safe, with a satisfactory 86% healing rate for complex fistulas. This is the largest anal fistula series to date.

Video demonstration of the modified Parks' technique for treatment of trans-sphincteric anal fistula

BACKGROUND

Trans-sphincteric anal fistula (TAF) is a common type of anal fistula that can be divided into low and high subtypes. Sphincter-sparing surgery is usually used for treatment of high TAF to avoid any compromise of the anal continence.

METHODS

A 38-year-old male patient with recurrent Grade III TAF was treated with the modified Parks' technique. This technique can be summarized as three main steps; each addresses a component of the anal fistula. (1) The extra-sphincteric component, which lies outside the external anal sphincter (EAS), is laid open with electrocautery. (2) The intersphincteric component is laid open, starting from the internal opening, dividing the internal anal sphincter, until the EAS fibers were reached. (3) The trans-sphincteric component that traverses the EAS was carefully curetted from the anal and the outer sides with a surgical curette. An important step of the procedure is to close the defect through which the fistula tract passed through the EAS with interrupted sutures.

RESULTS

The operation time was 35 min. Complete healing was achieved in 5 weeks with no persistence or recurrence of the anal fistula after a follow-up of 6 months. No affection of the continence state was recorded.

CONCLUSION

The modified Parks' technique is a simple and convenient operation for TAF. Further prospective studies are needed to substantiate the efficacy and safety of the procedure.

Modification of Parks Classification of Cryptoglandular Anal Fistula

BACKGROUND

The Parks classification has been used for the classification of anal fistula for several years, but it does not allow for risk factors for failure after surgery.

OBJECTIVE

This study aimed to describe a modification of the Parks classification of anal fistula and examine its predictive validity in the assessment of the outcome of anal fistula in terms of failure of healing and fecal incontinence.

DESIGN

This is a retrospective review of a prospective database.

SETTING

This study was conducted in the Colorectal Surgery Unit, Mansoura University Hospitals.

PATIENTS

Adult patients with anal fistula who underwent surgery were included.

INTERVENTIONS

Five risk factors for failure after fistula surgery were identified from the literature and were examined by multivariate analysis of our patients. Four risk factors proved to be significant independent predictors of failure: secondary extensions, horseshoe fistula, previous fistula surgery, and anterior anal fistula in women. We modified the Parks classification by dividing the transsphincteric type into high and low and by grouping supra- and extrasphincteric anal fistulas into 1 group. The first 3 stages were subdivided according to the absence or presence of predictors of failure.

MAIN OUTCOME MEASURES

The primary outcome measured was the validity of the modified Parks classification with regard to the rates of failure and fecal incontinence after surgical treatment of each stage of anal fistula.

RESULTS

A total of 665 patients with cryptoglandular anal fistula were included. Failure rates increased from 2.3% (95% CI, 0.9%-4.7%), to 17.4% (95% CI, 10.8%-25.9%), 19.5% (95% CI, 15%-24.6%), and 30.7% (95% CI, 9.1%-61.4%) across the 4 stages. The area under the receiver operating characteristic curve was 0.90 (95% CI, 0.85-0.94) indicating the strong discriminative ability of the final multivariable predictive model. The increase in failure and incontinence rates across the fistula stages was significant.

LIMITATIONS

This is a retrospective, single-center study.

CONCLUSION

Inclusion of predictors of poor outcome into the modified classification helped differentiate simple and complex fistulas within each stage and between the different stages, which can help in assessment and decision making for anal fistula. See Video Abstract at http://links.lww.com/DCR/B441.

MODIFICACIN DE LA CLASIFICACIN DE PARKS DE LA FSTULA ANAL CRIPTOGLANDULAR

ANTECEDENTES:La clasificación de Parks se ha utilizado para la clasificación de la fístula anal durante varios años, sin embargo, no tuvo en cuenta los factores de riesgo de fracaso después de la cirugía.OBJETIVO:Describir una modificación de la clasificación de Parks de fístula anal y examinar su validez predictiva en la evaluación de los resultados de la fístula anal en términos de fracaso de la cicatrización e incontinencia fecal.DISEÑO:Revisión retrospectiva de la base de datos prospectiva.AJUSTE:Unidad de Cirugía Colorrectal, Hospital Universitario de Mansoura.PACIENTES:Pacientes adultos con fístula anal intervenidos quirúgicamente.INTERVENCIONES:Se identificaron cinco factores de riesgo de fracaso después de la cirugía de fístula de la literatura y se examinaron mediante análisis multivariante de nuestros pacientes. Cuatro factores de riesgo demostraron ser importantes predictores independientes de fracaso: extensiones secundarias, fístula en herradura, cirugía de fístula previa y fístula anal anterior en mujeres. Modificamos la clasificación de Parks dividiendo el tipo transesfinteriano en alto y bajo y agrupando la fístula anal supraesfinteriana y extraesfinteriana en un grupo. Las tres primeras etapas se subdividieron según la ausencia o presencia de predictores de fracaso.PRINCIPALES MEDIDAS DE RESULTADO:Validez de la clasificación de Parks modificada con respecto a las tasas de fracaso e incontinencia fecal después del tratamiento quirúrgico de cada etapa de la fístula anal.RESULTADOS:Se incluyeron 665 pacientes con fístula anal criptoglandular. Las tasas de fracaso aumentaron del 2,3% (IC del 95%: 0,9-4,7%), al 17,4% (IC del 95%: 10,8 al 25,9%), 19,5% (IC del 95%: 15-24,6%) y 30,7% (95% IC: 9,1- 61,4%) en las cuatro etapas. El área bajo la curva característica operativa del receptor fue 0,90 (IC del 95%: 0,85-0,94), lo que indica una fuerte capacidad discriminativa del modelo predictivo multivariable final. El aumento en las tasas de fracaso e incontinencia en las etapas de la fístula fue significativo.LIMITACIONES:Estudio retrospectivo, unicéntrico.CONCLUSIÓN:La inclusión de predictores de mal resultado en la clasificación modificada ayudó a diferenciar las fístulas simples y complejas dentro de cada etapa y entre las diferentes etapas, lo que puede ayudar en la evaluación y toma de decisiones para la fístula anal. Consulte Video Resumen en http://links.lww.com/DCR/B441.

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

AIM

Treatment of transsphincteric fistulas (TSFs) with fistulotomy after an indwelling seton is tempered by risks of incontinence and litigation. Thus, ligation of the TSF tract has been popularized as an alternative option. We previously reported on 107 patients who underwent ligation of the intersphincteric fistula tract (LIFT), with a 46% failure rate. Posterior fistula was the only predictor of recurrence. The aim of the present work was to investigate whether the length, width or depth of the fistula measured on preoperative MRI was correlated with recurrence.

METHOD

Following institutional review board approval, a retrospective analysis of our prospective Complex Anal Fistula Database from 1 January 2011 to 31 August 2019 was performed. Patients with TSF who underwent preoperative MRI and LIFT were included. Fistula location was classified as anterior, posterior or lateral. MRI measurements of fistula length, width and depth (in the intersphincteric groove) were performed. The type and rate of postoperative recurrence were analysed.

RESULTS

173 patients underwent MRI for an anal fistula; of these 40 underwent LIFT and 22/40 (55%) had preoperative MRI. There was no difference in the length, width or depth of anterior (n = 9), posterior (n = 7) or lateral (n = 6) fistula tracts. The overall recurrence rate was 9/22 (41%). Posterior TSFs had the highest recurrence rate (5/7, 71%).

CONCLUSION

The mean length, width, and depth of the fistula tract, measured at the preoperative site of LIFT in the intersphincteric groove, did not correlate with recurrence regardless of fistula location.

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.

Best non-contrast magnetic resonance imaging sequence and role of intravenous contrast administration in evaluation of perianal fistula with surgical correlation

PURPOSE

To evaluate the best non-contrast magnetic resonance imaging (MRI) sequence and role of intravenous contrast administration in preoperative characterization and classification of perianal fistulae, keeping surgery as gold standard.

METHODS

This prospective study comprised of forty-five consecutive patients with actively draining external perianal opening. MRI was performed on a 1.5 T scanner using non-contrast and contrast enhanced sequences in multiple planes. St. James's University Hospital MRI based classification system was used to classify the fistulae into five grades. Taking surgery as gold standard, association between surgical and MRI findings was statistically analysed.

RESULTS

Of the 45 patients recruited, forty were deemed eligible for inclusion. Mean age was 39.7 ± 11.7 years with male preponderance (M: F = 8:1). Commonest type was Grade 1 (40%). The best sequences in terms of overall accuracy were axial & coronal planes of contrast enhanced fat suppressed (FS) T1W turbo spin echo (TSE) (95.7%) followed by FS T2W TSE (94.1%) while sagittal T2W TSE sequence with or without fat suppression had the lowest accuracy (90.13%). The difference in overall diagnostic accuracy of FS T2W TSE and contrast enhanced FS T1W TSE sequence for evaluating perianal fistula was not statistically significant (p = 0.52). However, contrast study had a better accuracy in detecting internal openings and secondary tract of recurrent/ post-operative cases.

CONCLUSION

Best non-contrast MRI sequence is FS T2W TSE (axial and coronal). Non-contrast MRI is equally efficient to contrast study while evaluating primary/previously unoperated cases thereby eliminating the role of contrast in such cases. However, intravenous contrast should be administered for evaluating post-operative cases with recurrence.

Management of perianal fistula in inflammatory bowel disease: identification of prognostic factors associated with surgery

PURPOSE

As one of the clinical manifestations of inflammatory bowel disease (IBD), perianal fistula disease (PFD) can potentially impact the patient quality of life. The management of PFD employs a multidisciplinary approach which includes antibiotics, biological therapies, immunomodulators, and surgery. We analyzed the outcome and prognostic factors of anal fistula surgery in IBD patients.

METHODS

We conducted a retrospective study of IBD patients undergoing elective surgery for anal fistula between January 2015 and December 2018 at our University Department of Surgery. We collated demographic factors, disease activity, imaging (MRI and endoanal ultrasound), surgical interventions, and medical treatment assessing the rate of fistula closure and fecal incontinence, 2 months and 1 year after surgery.

RESULTS

Thirty-five IBD patients with anal fistula underwent surgery (28 Crohn's disease, four ulcerative colitis, and three indeterminate colitis). Twenty-seven patients presented with complex fistulas and eight with simple fistulas with 10 patients undergoing single-stage surgery. In 25 patients, a two-stage surgical approach was planned and performed (draining seton plus medical treatment and then second-stage surgery with curative intent). At 1 year of follow-up, the fistula healing rate was 50% for single-stage surgery and 60% for two-stage surgery (P = 0.09). Overall, 19.2% of patients developed postoperative fecal incontinence. A time interval greater than 12 months between surgeries is a favorable prognostic factor for fistula healing with the two-stage approach (P = 0.002).

CONCLUSIONS

In our retrospective study, two-stage surgery in IBD patients presenting with complex perianal fistulous disease results in a better medium-term outcome with a longer time interval between surgeries.