Individuals with diseases that reduce the body's immunity -such as AIDS or cancer- are at a higher risk of anal abscess and fistula formation [1]. However, despite the higher incidence of fistula formation, no differences were observed concerning the healing time in simple fistulas [2]. On the contrary, healing and complication rates were altered in complex fistulas [3].

In all individuals, definitive treatment of a fistula aims to control the purulent discharge and prevent its recurrence. Treatment depends mainly on the trajectory of the fistula and the underlying disease leading to the fistula formation [4, 5]. The standard treatments that can be used are various, mostly surgical in nature, including fistulotomy, excision of the external fistula tract, closure of the internal opening, curettage, endorectal advancement flap, a cutting seton or immediate reconstruction [6].

Fibrin glue pluging is a method explored in recent years in various types of fistulas with great success [7–9]. Recently, fibrin glue has been applied in perianal fistulas with diverse success rates [4, 5, 10].

We present a special case of a HIV-positive patient with a complex extrasphincteric anal fistula who was treated successfully with fibrin glue application. We further, discuss tips and tricks when applying fibrin glue as plugging material in fistulas.

Anal fistulas are divided into 4 categories, with the suprasphincteric category being the rarest and representing approximately 1% of the total number of fistulas. The present fistula additionally, enters in the category of "complex" fistulas after the definition given by Loungnarath et al [11]. By this definition "complex" annals fistulas are those in which treatment by simple fistulotomy would result in significant impairment of continence. This category generally consists of high transsphincteric, suprasphincteric and extrasphincteric fistulas. The treatment of complex anal fistulas is one of the most challenging aspects of coloproctology and colorectal surgery.

The complexity of the present case is aggravated by the fact that the patient is HIV-positive. Approximately 30% of patients with HIV develop anorectal abscesses and fistulas [3]. Anal fistulas in HIV-positive patients arise from the dentate line in similar locations to human immunodeficiency virus-negative patients [12]. Anorectal procedures (for anal condylomata, fistula in ano, hemorrhoids, and perirectal abscess) are the most common operations performed in HIV-patients. No prospective data are available on operative morbidity and mortality in HIV-positive and HIV-negative patients. In retrospectives studies, investigators found a high incidence of serious wound complications after anorectal surgery and urged non-operative treatment for most anorectal diseases in HIV-infected patients [2, 3]. Although there is currently no scientific data on the prevalence of surgical complications among HIV patients compared to non-infected patients in colorectal surgery, it is more safely to avoid any type of major surgical treatment, as these patients have a weakened immune system. In this perspective, alternatives to conventional surgery were considered to the present patient.

Alternative to conventional surgery in complex anal fistulas are considered the use of fibrin glue (autologous or commercial) and the use of a biologic fistula plug (Surgisis^®AFP™). Among those two choices we chose the first. Our choice was based on the fact that we had no experience with Surgisis and that all studies employing this material date less than 5 years, not permitting to evaluate the long-term results [13, 14]. On the other hand, fibrin glue application is a safe, cheap, reproducible, pain-free procedure, which eliminates the possibility of anal incontinence and can be performed under local anaesthesia [15]. The fibrin glue application in the treatment of anal fistula is the guaranteed preservation of the sphincters, so it avoids the risk of incontinence, and creates minimal stress for the patient [4, 5, 10]. However, a final question arises -mainly theoretically- when coming to fibrin glue application: autologous or commercial? To our opinion commercial sealants have an advantage over autologous ones. Our impression seems to correlate well with the meta-analysis of Hammond et al [10]. According to this meta-analysis commercial sealants have been shown to bond more consistently -by up to 10 times stronger than autologous when compared in vitro-, take less time to prepare and do not require autologous blood transfusion. This was the reason why commercial fibrin glue was employed for plugging the anal fistula in the present case.

The best treatment for a disease is the one that gives at least the same result with the others with minimised risk for the life of the patient and minimal application effort. Conservative closure of fistula with fibrin tissue sealant is simple and especially in recurrent and difficult cases. Although anal fistula surgery is associated with considerable morbidity, mainly related to anal incontinence, our patient was successfully treated with the minimally invasive method by using fibrin glue, without endangering his life despite his precarious medical state. Despite the fact that not everybody believes in the effectiveness of fibrin glue application on anal fistulas, we suggest considering this solution in cases of complex fistulas at least as primary procedure in special populations such as the immunosupressed.

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.