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 . 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 . Anal fistulas in HIV-positive patients arise from the dentate line in similar locations to human immunodeficiency virus-negative patients . 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 . 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 . 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.
Tips and tricks
We believe that in the present case we had a successful closure of the fistula due to tips and tricks that we have extracted from our experience both in simple anal fistulas and fibrin glue application. Patients' history and old hospitalizations have to be considered carefully in order to determine, if possible, the aetiology of the fistula and the predisposing factor. The visualization of fistulas' canal is of prime importance before any intervention -either surgical or not-. The preoperative evaluation includes colonoscopy, fistulography and MRI of the pelvis. In that way, the tract of the fistula is known before any intervention. Once the fistula is a "complex" one, then adequate treatment is applied after considering the general condition of the patient. In case of fibrin glue application, we perform no pre-operative bowel preparation. This strategy is in the same context as for all colonic operations in our department: intact colonic flora offers better healing . Immediately, before the fibrin glue application we like to perform a new fistulography. Once the fistula tract is visualized we perform blunt curettage. Mechanical curettage stops when blood exits the external orifice of the fistula. After that, chemical cleansing with hydrogen peroxide follows aiming both in introducing oxygen radicals in the fistula (bactericide) and in achieving haemostasis. Following that, catheterization of the fistula tract is achieved with a catheter that has a slightly smaller in diameter than the fistula. A small quantity of radioopaque material is introduced into the catheter in order to assure that its tip is placed in proximity to the internal orifice. The fibrin glue is then prepared by an assistant and a plastic double-lumen Y-connector joins the two syringes. The connector is connected to the catheter introduced in the fistula and secured. Coordination is primordial in the last phase of application since with one hand we should push the glue through the syringe into the fistula, while with the other we slowly retract the catheter tip through the fistula. To our opinion this is the most important phase since it is the only one requiring familiarization with the material. Failure to coordinate the two movements will lead to misplacement of the glue and failure of the procedure. A large drop of glue should be reserved to seal the external orifice of the fistula. Antibiotics and immobilization of the patient -in our opinion- offer nothing as post-interventional measures.