Cej. Sloots et al., Assessment and classification of fistula-in-ano in patients with Crohn's disease by hydrogen peroxide enhanced transanal ultrasound, INT J COL R, 16(5), 2001, pp. 292-297
Crohn's disease is well known for its perianal complications, among which f
istulas-in-ano are the most common abnormalities. Fistulas-in-ano in Crohn'
s disease tend to be complex and have a high recurrence rate. Therefore the
role of surgery is generally more conservative. Hydrogen peroxide enhanced
transanal ultrasound has proven superior to physical examination, fistulog
raphy, computed tomography, and conventional ultrasound in demonstrating th
e fistula tract. This study examined the fistula tracks in patients with Cr
ohn's disease. Forty-one patients with Crohn's disease and fistula-in-ano w
ere investigated using physical examination, sondage of the fistula, procto
scopy and transanal ultrasound. Hydrogen peroxide was infused via a small c
atheter into the fistula. The main track and the ramification of the fistul
a were classified according to the anatomical Parks' classification. Only 9
(22%) patients had a single inter- or transsphincteric fistula. In 5 (12%)
patients a single supra- or extrasphincteric fistula (high fistula) was fo
und, in 14 (34%) more than one fistula track (ramified), and in 13 (32%) an
anovaginal fistula. Thus 78% of patients had a surgically difficult to tre
at fistula. In the ramified fistula the main track follows the Parks' class
ification, but ramifications can have a bizarre pattern which is not in agr
eement with this classification. Optimal documentation by means of hydrogen
peroxide enhanced transanal ultrasound is therefore mandatory before surge
ry or before other therapies such as anti-tumor necrosis factor treatment.