Anorectal Abscess and Fistula-in-Ano: Evidence-Based Management

The role of multiparametric MRI (mpMRI) in prostate cancer setting is increasingly consolidated and, as a result, its usage in clinical practice is in exponential growth. However, beyond the prostate gland, several key structures are included in the field of view of mpMRI scans. Consequently, various extra-prostatic incidental findings (IFs) belonging to different anatomical systems can be accidentally recognized. Therefore, it is mandatory for a radiologist to be familiar with the wide range of pathologies potentially encountered, to guide management and avoid patient anxiety and costs due to additional work-up prompted by clinically insignificant extra-prostatic findings. With this pictorial review, we aim to illustrate a wide range of IFs that can be detected when performing mpMRI of the prostate, focusing on their imaging characteristics, differential diagnosis, and clinical relevance. Additionally, we propose the CheckDEEP, the Checklist for DEtection of ExtraProstatic findings, to be used for a thorough evaluation of target areas within each anatomical system.

The management of anal fistula remains a source of frustration for patients and surgeons alike. The continued challenge posed by this condition has led to considerable innovation and investigation with the ongoing refinement of surgical techniques, the development of new technologies, and the application of advanced biomaterials. This article will describe recent, ongoing, and future developments in the treatment of anal fistula.

Treatment of anorectal abscesses continues to revolve around early surgical drainage and control of perianal sepsis. Yet even with prompt drainage, abscess recurrence and postoperative fistula formation rates are as high as 40% within 12 months. These complications are thought to be associated with inadequate drainage, elevated bacterial load, or a noncryptoglandular etiology of disease. Postoperative antibiotics have been used to account for these limitations, but their use is controversial and only weakly supported by current guidelines due to low-quality evidences. The aim of the present study was to perform a systematic review and meta-analysis of the current literature to determine the role of antibiotics in prevention of anal fistula following incision and drainage of anorectal abscesses.

Literature search was conducted using Medline, EMBASE, Scopus, the Cochrane Library, and Web of Science databases from 1946 to April 2018. Search terms were “perianal OR anal OR fistula-in-ano OR ischiorectal OR anorectal AND abscess AND antibiotics” and was limited to human studies in the English language. Literature review and data extraction were completed using PRISMA guidelines. A total of six studies with 817 patients were included for systematic review. The weighted mean age was 37.8 years, 20.4% of patients were female, and the follow up ranged from one to 30 months. Antibiotic courses varied by study, and duration ranged from five to 10 days. Of included patients, 358 (43.8%) underwent management without antibiotics while 459 (56.2%) patients were treated with antibiotics. Fistula rate in subjects receiving antibiotics was 16% versus 24% in those not receiving postoperative antibiotics. Meta-analysis revealed a statistically significant protective effect for antibiotic treatment (3 studies, OR 0.64; CI 0.43–0.96; P = 0.03).

Antibiotic therapy following incision and drainage of anorectal abscesses is associated with a 36% lower odds of fistula formation. An empiric 5–10-day course of antibiotics following operative drainage may avoid the morbidity of fistula formation in otherwise healthy patients, although quality of evidence is low. Further randomized trials are needed to fully clarify the role, duration, and type of antibiotics best suited for postoperative prevention of fistula following drainage of anorectal abscesses.

Anorectal abscess and fistula are a common clinical problem. In the majority of cases, caused by infection of the anal gland, surgical treatment is usually required. In a minority, when related to Crohn's disease, medical treatment is the mainstay. The aim of treatment is to maximize the healing rate and minimize the risk of incontinence. To achieve these goals, preoperative investigation is necessary for classification and planning. Selection of the technique should be based on the disease (classification and etiology), the patient (physical and continence status), and the surgeon (technique and technology). This chapter provides a review of these conditions, classification, investigation, and treatment options.