[Identification of internal fistolous orifice: evolution of methylene blue technique with a mini-probe]

Often perianal fistulas can be difficult typing and traditional anatomical classifications do not help the surgeon in accurate diagnosis of the fistula as an outpatient procedure and therefore does not allow a timely surgical currettage. The aim of our study was to introduce in the management of anal fistulas performed on an outpatient injection with methylene blue of the fistula through a small polyethylene catheter in order to detect in real time the internal opening of the fistula and drive so the next currettage surgery.

A total of 50 consecutive patients 21 female and 29 male, relating to our clinic with symptoms suggestive of colon proctology perianal fistula, aged between 36 and 69 years were selected for our study. After running the news-gathering medical history, physical examination, digital examination through examination anoscope, using a polyethylene catheter in a small scale, of methylene blue was injected through the external fistula orifice looking inside the spreading of liquid. Subsequently, the patient was started on specillazione currettage and possible surgery.

62 outpatients were treated intramural fistulas, diagnosed with the injection technique with methylene blue running always probing and practiced a wide dish made of the mucosa, submucosa and circular muscle layer of the internal drainage with sphincterotomy. In particular, the technique injection of methylene blue was sufficient to diagnose 42 out of 62 cases examined (67.7%). In the remaining 20 cases it was necessary to integrate diagnosis with MRI-defecates on the complexity of fistulas (10 horseshoe, 6 trans sphincteric and 4 intersphincteric.

Methylene blue injection is a low-cost screening technique, simple to perform on an outpatient basis and in the case of suprasphincteric fistulas also a simple diagnostic technique is sufficient to allow the closure of the fistula.