Treatment of Anal Fistulas by Partial Rectal Wall Advancement Flap or Mucosal Advancement Flap: a Prospective Randomized Study

This study comprises a prospective study of 40 patients with transphincteric anal fistula. They were referred to our colorectal surgery unit, Mansoura University Hospital during the period from May 2005 to May 2008. Patients with acute sepsis, specific cause of fistula, strictured anorectum, and any degree of incontinence were excluded from the study.

All patient were evaluated by digital examination, procto-sigmoidoscopy, fistulography and MRI fistulography without contrast media, using a 1.5 Tesla super conducting magnet (Magnetom Symphony MRease VA12 Siemens medical system), (either STIR or SPIR in addition to T1 weighted or T2 weighted sequences). Axial, coronal and sometimes sagittal planes were used. Preoperative assessment of anal sphincter dysfunction was done by conventional manometry using a standard low compliance water perfusions system and eight-channels catheters with pressure transducer connected to 5.5 mm manometric probe with spirally located ports at 0.5cm interval, which measured along the length of the anal canal, as well as inflatable rectal balloon. The protocol of performance is stationary pull through technique with recording the functional length of the anal canal (FL), mean maximum resting pressure in the anal canal (MRP), mean maximum squeeze pressure in the anal canal (MSP). Pressure was recorded using a computerized recording device (MMS ;Holland) which included menu-driven software to aid with data acquisition. Data were analyzed with the use of a complied software package that automatically produced numeric reports and graphs.

The patients were then classified into 2 groups. After carefully explaining the purpose of the study, an informed consent was taken from every patient. Group I: Fistulectomy, closure of internal sphincter with loose vicryl 3(0) suture and rectal advancement flap (the length 5cm of the flap is twice its width) includes mucosa, submucosa, circular muscle layer sutured 1cm below the level of internal opening. Group II: The same as group one but the flap includes only mucosa and submucosa.

Surgical technique:

Fleet enema was used for preoperative bowel preparation in all cases. Operation was done under general anesthesia in the lithotomy position. Prophylactic antibiotics were used with ciprofloxacin 500 mg and metronidazole 500 mg preoperatively and twice daily for 5 days. Examination under anaesthesia (EUA) was firstly performed and the extent of the disease was established by cannulating the fistulas with probes and by laying open all primary tracts, extensions, and abscesses. All the incisions and dissections were made by electrocautery. The standard procedure was to perform core fistulectomy and traversing the external sphincter until the internal sphincter was exposed the track was then transected. The crypt-bearing tissue around the internal opening of the fistula is excised, if there is difficulty in excising the main tract, the granulation tissue of the remaining tract is scraped with a curette. Advancement flap was constructed in both group.