EVOLUTION OF PATHOMORPHOLOGICAL CHANGES IN THE FISTULOUS TRACT IN PATIENTS WITH RECTAL FISTULAS

Abstract

AIM. To assess pathomorphological changes in perianal fistulas to estimate rationale for FILaC procedure. PATIENTS AND METHODS. Cohort study included 76 patients, 42 (55.3%) females, aged 23-72 (median 42.7) years. Traditional fistulectomy was performed in 37 (48.7%) of them, 39 (51.3%) underwent FILaC procedure (laser coagulation of fistula track with excision of extrasphincteric part of fistula and preservation of intershincteric part). Histological study was performed in all cases with hematoxylin-eosin staining. RESULTS. Fistula morphological structure varied depending of duration of the disease. No fibrous capsule was detected in fistulas track up to 6 weeks, young connective tissue was found within 8-12 weeks and prominent fibrous capsule - after 12 weeks. A depth of laser coagulation thermal impact was 1.5±0.5 mm in cases with duration of disease >12 weeks, in cases <6 weeks - 5.0±1.0 mm (p<0.0001). CONCLUSION. Depth of thermal impact of laser coagulation depends of duration of the disease and it is not safe in patients withfistula natural history less than 6 weeks.