Hydrogen peroxide enhanced ultrasound- fistulography in the assessment of enterocutaneous fistulas complicating Crohn's disease

Abstract

Background/aims: Proper management of enterocutaneous fistulas complicating Crohn's disease largely depends on the anatomical characteristics of the sinus tracks as well as the coexistence of complications such as abscesses and distal bowel stenosis. The aim of this prospective study was to evaluate the accuracy of a new technique (hydrogen peroxide enhanced ultrasound (US)-fistulography) compared with conventional x ray fistulogram and/or surgical findings in the detection of Crohn's disease associated enterocutaneous fistulas.

Methods: Patients with known Crohn's disease and a suspicion of enterocutaneous fistulas were prospectively studied with this novel technique, conventional x ray fistulogram, and barium radiography as well as with computed tomography whenever an abdominal abscess was suspected at US. In those undergoing surgery, intraoperative findings were also compared.

Results: Seventeen of 502 (3.4%) consecutive patients with Crohn's disease seen over a ten month period had associated enterocutaneous fistulas and were enrolled. Hydrogen peroxide enhanced US-fistulography visualised the extent and configuration of fistula in all cases: 13 patients had a fistula arising from the ileum and two from the sigmoid colon, whereas in two there was no evidence of communication with intestinal loops; in contrast, conventional x ray fistulography missed a correct definition of the fistulous branches or communication with intestinal loops in 50% (4/8) and 36% (4/11) of patients respectively; barium radiography showed fistulas in two cases only. The presence of abscesses along or close to the sinus track, as well as the coexistence of intestinal stenosis, was correctly detected at US in all patients.

Conclusions: Hydrogen peroxide enhanced US-fistulography could be considered the diagnostic procedure of choice in Crohn's disease associated enterocutaneous fistulas, as it is at least as accurate, simple, and safe as conventional x ray fistulogram, does not miss coexisting abdominal complications, and also provides information on the diseased bowel segments. In addition, it can be easily repeated over time in order to monitor the course of fistulas undergoing conservative treatment.

Figure 1

Enterocutaneous fistula which appears to be simple (arrow) at conventional US (A). Injection of the hydrogen peroxide solution into the sinus track discloses a complex sinus track (B, C), with two major branches (arrow) and a clear communication with an ileal loop (arrow) (C). Conventional x ray fistulogram shows only a simple sinus track (arrow) apparently not in communication with the bowel (D, E).