The Best Surgical Treatment for Fistula-in-ano Dr John Wong PYNEH

Etiology Cryptoglandular theory Trauma Foreign body Iatrogenic Malignancy Crohn’s disease Tuberculosis HIV Suspected secondary cause: Known Hx of crohn, TB Proctitis Complex fistula (recurrent after adequate Tx, multiple track, high fistula) J.G.Williams et al. Colorectal Disease 2007

Classification Park’s classification (1976) Inter-sphincteric (~45%) Trans-sphincteric (~30%) Supra-sphincteric (~20%) Extra-sphincteric (~5%) J.G.Williams et al. Colorectal Disease 2007

Goodsall’s rule 49% 90% J.G.Williams et al. Colorectal Disease 2007 Exception: Horseshoe fistula Long track that extend to the anterior quadrant of the anal canal Crohn’s Iatrogenic 90% J.G.Williams et al. Colorectal Disease 2007

Investigation

Investigation Indications: Complex fistula Impaired sphincter function Suspicious of secondary cause

Investigation Anatomy Physiology Cause Endoanal Ultrasound, MRI Anorectal manometry Cause Inflammatory marker, colonoscopy, rectal biopsy

Endoanal Ultrasound High accuracy (93%) to identify the internal opening Injection of hydrogen peroxide can increase the detection rate 3 criteria for identification of internal opening by USG - contact of the sphincter by the intersphincteric track Apparent defect of the internal sphincter A defined subepithelial track associated with a localized sphincter defect 7-10 MHz ANZ J. Surg. 2005; 75: 64-72 J.G.Williams et al. Colorectal Disease 2007

Endoanal Ultrasound Disadvantage: Pain and discomfort Operator dependent Limit field ~2cm from probe Limited use for trans-sphincteric or more complex FIA! High frequency probe -> limited fied Not for trans-sphincteric fistula

MRI Gold standard Multi-planar image Show the fistula system in relation to the underlying anatomy High sensitivity Primary track: 86% Secondary track: 91% Horseshoe extesion 97% ANZ J. Surg. 2005; 75: 64-72 J.G.Williams et al. Colorectal Disease 2007

Treatment

Principles of management To drain abscess To deal with the secondary track if any Definitive treatment of the primary track Efficacy Continence

Fistulotomy Lay-opening of the fistula track from external opening to internal opening Inter-sphincteric fistula Recurrence rate 0-21% Disturbance in continence: 0 to 82% Extent of external sphincter division: <30% Other risks factor for incontinence Females, anterior fistula, association with Crohn’s disease and prior fistula surgery J.G.Williams et al. Colorectal Disease 2007

Fistulectomy Excision of the entire fistula track Low lying fistula No advantage in both recurrence and incontinence rate compared with fistulotomy High lying fistula ‘Core out’ technique + internal sphincterotomy For patho assessment Excision of the extra-sphincteric part of the trans-sphincteric fistula Surgical intervention for anorectal fistula. The Cochrane Collaboration 2010

Fistulectomy + Internal Sphincterotomy

Seton Loose seton Achieve drainage of the fistula track Allow any secondary track to heal As part of staged fistulotomy J.G.Williams et al. Colorectal Disease 2007

Staged fistulotomy Low recurrence rate Significant rate in incontinence Major incontinence rate up to 42% J.G.Williams et al. Colorectal Disease 2007

Seton Tight (cutting) seton Commonly used in high transphincteric fistula Divide the muscle slowly to produce a gradual fistulotomy Recurrence rate 0-18% Disturbance of fine control is common Major incontinence rate ~10% J.G.Williams et al. Colorectal Disease 2007

Disturbance of fine control is common Low recurrence rate Disturbance of fine control is common Major incontinence rate >10% (up to 43%) Recurrence rate 0-18% Disturbance of fine control is common Major incontinence rate ~10% J.G.Williams et al. Colorectal Disease 2007

Fibrin Glue Fibrin clot to seal the track Stimulate the migration, proliferation and activation of the fibroblasts Sphincter-sparing method Activated mixture of fibrinogen, factor XIII, fibronectin & aprotinin (Tisseel, Viguard and Beriplast) A.I. Malik & R.L. Nelson; Colorectal Disease 2008

Fibrin Glue High recurrence rate Long term healing rate(~14% - 60%) A.I. Malik & R.L. Nelson; Colorectal Disease 2008

Anal Fistula Plug Sphincter-sparing method Bioprosthetic plug Internal opening must be identified Initally rehydrated for 1-2min Plug pull through the track from the internal opening Sutured in the int opening Ext opening lay open Excessive plug cut Advise to avoid heavy lifting / straining for 2wk

Anal Fistula Plug Controversial results from different centre Low success rate Controversial results from different centre(14%-87%) Shawki S et al. World Journal of Gastroenterology 2011 P. Garg et al. Colorectal Disease 2010 PYNEH 11 5 45% P. Garg et al. Colorectal Disease 2010 HYS Cheung et al. Surgical Practice 2009

Advancement Flap + core out fistulectomy Sphincter-sparing method Pre-op bowel prep and antibiotics cover Internal opening must be identified +/- temporary diverting stoma U-shaped muco-muscular flap Fistula track is cored out Closure of the internal defect Suture the flap with absorbable stitches Ext opening lay open

Advancement Flap + core out fistulectomy Low long term success rate ~ 13%-56% High recurrence due to: Small flap Excessive tension Low long term success rate High recurrence due to: Small flap Excessive tension J.G.Williams et al. Colorectal Disease 2007

LIFT Ligation of Intersphincteric Fistula Tract Rojanasakul in 2007

LIFT Short term success rate was encouraging (~57-94%) Long term result still unknown Arch Surg. 2011;146(9):1011-1016

Conclusion No single best treatment for FIA Treatment for FIA must be individualized Types of the fistula Premorbid sphincter function

Recommendation Fistulotomy Inter-sphincteric fistula (High / low lying, with or without internal opening) Fistulotomy

Trans-sphincteric / Supra-sphincteric fistula No internal opening Fibrin Glue Core out fistulectomy + exploration of inter-sphincteric plane +/- internal sphincterotomy

Trans-sphincteric / Supra-sphincteric fistula With internal opening High risk of incontinence AFP Advancement Flap Core out fistulectomy + internal sphincterotomy Cutting seton / Staged Fistulotomy Low risk of incontinence

Recommendation Extra-sphincteric fistula Usually associated with an underlying cause Treat the underlying cause Drain any sepsis Never disrupt or explore the sphincter

Thank you!

Exception for Goodsall’s rule Horseshoe fistula Long track that extend to the anterior quadrant of the anal canal Crohn’s disease Iatrogenic

Fistulogram Accuracy ~16-50% only Difficult to relate the track to the sphincter anatomy The acute track are just column of granulation tissue without a lumen Need external opening Painful

Fistulotomy in acute anorectal sepsis Pros: decrease the rate of recurrent anorectal sepsis Cons: increase risk of impair continence Some individuals would have unnecessary surgery Fisulotomy should be performed when internal opening can be found and the fistula is submucosal or intersphincteric (low lying) J.G.Williams et al. Colorectal Disease 2007

Radiofrequency fistulotomy Use of radio-wave as energy source Less bleeding Less pain Quicker recovery No difference in recurrence and incontinence rate Surgical intervention for anorectal fistula. The Cochrane Collaboration 2010

Fistulotomy with marsupialization Suturing the edge of the track to its base Less bleeding Shorter healing time No difference in recurrence and incontinence rate Surgical intervention for anorectal fistula. The Cochrane Collaboration 2010

Fistulotomy vs Fistulectomy No difference in recurrence and incontinence rate A.I. Malik & R.L. Nelson; Colorectal Disease 2008

Chemical seton Coated with layers of latex and plant extracts Strong alkaline outer layer Cut through tissue at a rate of 1cm every 6 days More painful Evidence on recurrence and healing rate remain inconclusive A.I. Malik & R.L. Nelson; Colorectal Disease 2008

Anal fistula plug Better outcome in : Deep trans-sphincteric fistula Long track fistula Narrow-gauge fistula

Advancement Flap Contra-indications: Presence of proctitis Undrained sepsis Malignant / radiation related fistula Stricture of the anorectum Severe sphincter defect Severe peripheral scaring due to previous surgery J.G.Williams et al. Colorectal Disease 2007

FIA with Crohn’s disease Medical treatment, eg. Anti TNF-alpha Infliximab Emergency treatment Incision and drainage of the fistula Stabilization Insertion of seton to optimize drainage and medical therpay J.G.Williams et al. Colorectal Disease 2007

Incontinence scale Flatus, mucus, liguid, solid stool The Cleveland Clinic (Wexner) Incontinence Score sum of 5 parameters is on a scale from 0 (=absent) to 4 (daily) frequency of incontinence to gas, liquid, solid, of need to wear pad, and of lifestyle changes.