Outcome after surgery for perianal fistula: predictive value of MR imaging.

Abstract

OBJECTIVE. The purposeof thisstudywasto determineif MR findingsarepredictiveof long-term outcome in a cohort of patients whose initial surgery was performed without access to the findings of MR imaging. SUBJECTS AND METHODS. Forty patientswith surgicallyprovenperianal fistulasunderwent preoperative dynamic contrast-enhanced MR imaging. The MR and surgical find ings were independently recorded on an identical anatomic form. Three patients were subse quently lost to follow-up. The outcome for the remaining 37 patients was determined from surgical review, case notes, and questionnaires. Minimum follow-up period was 14 months (range, 14â€"39 months).Outcomewas determinedby one observerwho was unawareof the initial MR grading and had not been present during surgery. Outcome was considered unsatis factory if further surgery was required. RESULTS. MR imagingwasbetterthansurgical explorationin predictingoutcome(for MR imaging:positivepredictivevalue,73%; negativepredictivevalue,87%; sensitivity, 89%; and specificity, 68%; for surgical exploration: positive predictive value, 57%; negative predictive value, 64%; sensitivity, 73%; and specificity, 47%). MR classification of fistulas was signifi cantlyassociated with outcome(p = .0004), andsurgical classification wasnot significantlyas sociated with outcome (p = .22, chi-square test). Also MR grades differed significantly for patientswith satisfactory and unsatisfactoryoutcomes(p < .001, Mann-Whitney U test).CONCLUSION. MR imaging is valuablein the managementof patientswith perianal fistulas.MR imagingaccuratelyrevealssurgicalanatomyandcanbe usedto makebetterpre dictionsregardingpatientoutcomethansurgicalfindings.

Ideal combination of sequences for perianal fistula classification and evaluation of additional findings for readers with varying experience

“…The location of the internal opening with respect to a clock face (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), the presence or absence of sinus tracks, abscesses, a horseshoe component and coexisting inflammation and the distance of the internal opening to the anal orifice (in mm) were noted for each of the MRI sequences listed above. It was also noted if no decision could be made.…”

“…These findings are consistent with the results of Spencer et al (6), who suggested that axial and coronal contrast-enhanced T1W and axial T2W sequences should provide adequate information to guide surgery. In our study, however, we evaluated a more detailed classification of fistulas and internal openings, the positions of which were indicated by reference to a clock face (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Also, additional findings, such as the presence of a horseshoe extension or inflammation, were evaluated separately.…”

MRI of Crohn?s Anoperineal Disease

“…At present, two classifications are most commonly used: a classification proposed by Parks in 1976, which was created for surgical use [29], and the St James University Hospital classification, which was developed based on a MRI examination [28,30] (Tables 1 and 2 …”

“…A study has shown that MR imaging is better than initial surgical exploration in the prediction of patient outcome [30]. When the St James's University Hospital classification was used, the MR imaging grading of fistulas was significantly associated with outcome: MR imaging grades 1 and 2 were associated with a satisfactory outcome (i.e.…”

Magnetic Resonance Imaging; The Best Imaging Technique in Detection of Perianal Fistulas With Diagnostic Accuracy

“…Some studies have suggested that MRI is even more sensitive than surgical exploration of the tracts. 15 Detection of branching fistulas is a diagnostic challenge because missed extension is the commonest cause of recurrence. MRI is especially helpful in such cases 11 and thus very helpful in guiding surgeons towards complete surgical cure, like in cases of chron's disease.…”