Anorectal: Lateral Internal Anal Sphincterotomy

Procedure

• Small Radial Incision Over the Intersphincteric Groove
• Site of Incision: Right Lateral
  • Between Anterior/Posterior Columns
  • Avoid Left Lateral Column
  • Posterior Incisions Result in “Keyhole Deformity” with Incontinence & Seepage
• Technique:
  • Open Technique:
    • Separate Internal Anal Sphincter from the Anal Mucosa
    • Partially Divide the Sphincter with Scissors
  • Closed Technique:
    • Insert a No. 11 Blade Scalpel Parallel to the Sphincter
    • Rotate the Scalpel 90 Degrees Medially and Partially Divide the Sphincter
• Cut Distal IAS
  • Proximal Extent of Incision: Proximal Extent of Fissure

Complications

• Failure to Heal
  • Cause: Inadequate Division of the Internal Anal Sphincter
• Fecal Incontinence
  • Risk:
    • Temporary: 44-50%
    • At Two Years: 15%
  • No Difference Between Open or Closed Technique
  • Higher Risk with Greater Length of Sphincter Division