S31.65AA Open bite of abdominal wall, unspecified flank with penetration into peritoneal cavity, initial encounter

Billable ICD-10-CM code, FY2026.

Built from S31.65A with 7th character A (initial encounter).

Applies from S31 Open wound of abdomen, lower back, pelvis and external genitals

Excludes1 (never code together)

• traumatic amputation of part of abdomen, lower back and pelvis (S38.2-, S38.3)

Excludes2 (not included here)

• open wound of hip (S71.00-S71.02)
• open fracture of pelvis (S32.1--S32.9 with 7th character B)

Code also

• any associated:
• spinal cord injury (S24.0, S24.1-, S34.0-, S34.1-)
• wound infection

7th character note

• The appropriate 7th character is to be added to each code from category S31

7th character required

• A — initial encounter
• D — subsequent encounter
• S — sequela

Applies from S31.65 Open bite of abdominal wall with penetration into peritoneal cavity

Excludes1 (never code together)

• superficial bite of abdominal wall (S30.861, S30.871)

Applies from S31.65A Open bite of abdominal wall, unspecified flank with penetration into peritoneal cavity

Applicable to

• Open bite of abdominal wall, flank NOS, with penetration into peritoneal cavity

Medicare Code Edits (MCE v43.1 (April 2026))

• Unspecified code (laterality): Unspecified codes for which a more specific code identifying laterality (right, left, bilateral) exists within the same code family.

Code annotations containing back-references to S31.65AA

Back-references to S31.6

• Type 2 Excludes: S31.1 Open wound of abdominal wall without penetration into peritoneal cavity ("open wound of abdominal wall with penetration into peritoneal cavity (S31.6-)")

Back-references to S31

• Code Also: S33.1 Subluxation and dislocation of lumbar vertebra ("open wound of abdomen, lower back and pelvis (S31)")
• Code Also: S34 Injury of lumbar and sacral spinal cord and nerves at abdomen, lower back and pelvis level ("open wound of abdomen, lower back and pelvis (S31.-)")
• Code Also: S35 Injury of blood vessels at abdomen, lower back and pelvis level ("any associated open wound (S31.-)")
• Code Also: S36 Injury of intra-abdominal organs ("any associated open wound (S31.-)")
• Code Also: S37 Injury of urinary and pelvic organs ("any associated open wound (S31.-)")
• Use Additional: S38.1 Crushing injury of abdomen, lower back, and pelvis ("open wound of abdominal wall (S31.-)")
• Code Also: S39 Other and unspecified injuries of abdomen, lower back, pelvis and external genitals ("any associated open wound (S31.-)")

Diagnosis Index entries for S31.65AA

• Bite (s) (animal) (human) › flank › with penetration into peritoneal cavity

Nearby codes

• S31.659 Open bite of abdominal wall, unspecified quadrant with penetration into peritoneal cavity
• S31.659A Open bite of abdominal wall, unspecified quadrant with penetration into peritoneal cavity, initial encounter
• S31.659D Open bite of abdominal wall, unspecified quadrant with penetration into peritoneal cavity, subsequent encounter
• S31.659S Open bite of abdominal wall, unspecified quadrant with penetration into peritoneal cavity, sequela
• S31.65A Open bite of abdominal wall, unspecified flank with penetration into peritoneal cavity
• S31.65AA Open bite of abdominal wall, unspecified flank with penetration into peritoneal cavity, initial encounter (this code)
• S31.65AD Open bite of abdominal wall, unspecified flank with penetration into peritoneal cavity, subsequent encounter
• S31.65AS Open bite of abdominal wall, unspecified flank with penetration into peritoneal cavity, sequela
• S31.8 Open wound of other parts of abdomen, lower back and pelvis
• S31.80 Open wound of unspecified buttock
• S31.801 Laceration without foreign body of unspecified buttock