Fistula

• Abnormal connection between two epithelial surfaces

Classification

1. Simple / Complex (associated with abscess cavity)
2. Anatomy
   • Respiratory: Bronchopulmonary fistula, tracheo-oesophageal
   • GI tract: tracheo-oesophageal, enterocutaneous, perianal
   • Urinary tract: entero-vesical fistula, urethrocutaneous (in circumcision)
   • Reproductive tract: Entero-vaginal fistula
   • Circulation system: arterio-venous fistula, AAAs
   • Salivary gland fistula (following parotidectomy)
3. High output (>500mls/day) or Low output
   • Associated electrolyte disturbance / fluid disturbance
   • Associated malnutrition & sepsis
4. Aetiology
   • Trauma/iatrogenic (AV fistula, post surgery, tracheostomy, earings)
   • Inflammatory (IBD)
   • Sepsis (from anastamotic leaks, abscesses)
   • Malignancy
   • Radiotherapy

Examples

• Earings
• Perianal fistula
• Enteric fistula (Crohn's disease)

Factors controlling healing

1. Local
   • Persisting cause / material
   • Persisting sepsis
   • Persisting flow through fistula
   • Width of fistula
   • Ischaemia
   • Epidermidisation of track
   • Malignant change
2. Systemic
   • Nutrition, vitamin deficiency
   • Immunosuppression - DM, AID

Principles in Management

Hope Hospital protocol - SNAP - Sepsis / Nutrition / Anatomy / Proceed

1. Sepsis
   • Remove cause
   • Drain abscess cavities
   • Avoid antibiotics
   • Skin protection
2. Nutrition to promote healing
   • Restrict / control fluid intake (determines output of fistula)
   • Total Parenteral nutrition / distal enteral nutrition
3. Anatomy
   • Fistulography
   • Bowel enema
   • CT / MRI: define abscess cavities
4. Procedure (1) excision - karydakis procedure (2) laying open (3) seton to cut through tract