1. Current Management of Fistula-in-ano
Dr. Leung Tak Lun Canice
Department of Surgery
North District Hospital

2. Case Presentation M/47 Hx of perianal abscess
On and off perianal discharge
P/E
FIA with external opening at 4 oc position, 3cm from anal verge
Internal opening at 4 oc, above dentate line

3. EUA and Rigid sigmoidoscopy
Transpincteric FIA with ext. opening at 4 oc
Internal opening at 4 oc, above dentate line
External tract at left ischorectal fossa excised
Seton inserted
Plan for tightening of seton in 4/52

4. At 2nd operation Seton already broken and lost
Basically healed fistula
Curettage of granulation tissue done

5. Recurrence!!
4 months later
c/o persistent discharge
MRI offered

6. MRI finding -> transphincteric type of FIA with bifurcation tract near the anus and ending at 5 and 7 o’clock position

7. Reoperation Intra-op finding
Transphincteric FIA with external opening at 4 oc
Internal opening at 4cm from anal verge just below level of levator ani but at the top of internal sphinter
Curettage of the track done and seton inserted again

8. Follow up
Well and no discharge

9. Etiology Pre-existing abscess Anal gland theory
Anal glands 8 or more in number
Form small abscess at interspincteric plane when infected
Other causes include congenital, pelvic sepsis, trauma, hidradenitis suppurativa, haemorrhoid, iatrogenic, inflammatory bowel disease, TB, maligancy

10. Parks Classification

11. Clinical presentation
Anal discharge preceded by episode of pain and perianal swelling
Repeated episode of perianal sepsis

12. Clinical assessment History Physical examination
Palpation of the perineum
Digital examination

13. Clinical assessment EUA Light GA Palpation
Methylene blue, hydrogen peroxide injection
probing

14. Imaging modality
Fistulogram
Endoanal ultrasound
MRI

15. Fistulography Disappointing Accuracy 16% only
Difficult to relate the track to the sphincter and levator ani
The acute track are just column of inflamed granulation tissue without a lumen

16. Endoanal ultrasound
High accuracy (93%) of predicting the site of internal opening of an anal fistula
Overall concordance for type of fistula is 82%
Colorectal Disease, 4,

17. Hydrogen peroxide improve the concordance with type of fistula from 80% to 89%
Colorectal Disease, 4,

18. Endoanal ultrasound

19. MRI Advantage of MRI Multiplanar imaging
High soft tissue differentiation to show the track system in relation to the underlying anatomy in a projection relevant to surgical exploration

20. MRI
Concordance rate with surgical exploration of 86% to 88% in initial reports
Currently
Up to 100% sensitivity for primary tract
96% for abscess
100% for horse extension
96% for internal opening

21. Axial / Coronal view

22. T1 axial T2 axial

23. T1 coronal T2 coronal

24. Gadolinium enhancement with fat suppression – axial view

25. Gadolinium enhancement with fat suppression – coronal view

26. Role of Imaging FIA has significant recurrence rate up to 25%
Due to part of the track system not being recognised at surgery
Inadequate drainage of sepsis
False communication found by injudicious probing

27. Radiology can demonstrate clinically undetected sepsis, can guide initial surgery and reveal the site of residual sepsis

28. In one prospective study of MRI in primary fistula (BJS 2002)
30 patients
MRI led to further exploration in 2 cases
1 patient require further surgery at a median FU of 12 months

29. Other prospective study (Lancet 2002; 360: 1661-2)
71 patients
Agreement between MRI and surgery in 25 cases -> 12% recurrence
MRI led to further surgery in 15 cases -> 13.3% recurrence
Disagreement in 31 cases but no further surgery undertaken -> 51.6% recurrence

30. Recurrence rate for individual surgeons who always, sometimes or never acted on the discrepant MRI finding were 16%, 30%, 57% respectively

31. Treatment outcome
Low FIA

32. Low FIA

34. Fibrin glue injection

35. The End