ICD-10-CM > S00-T88 > S30-S39 > S31 > S31.0 > S31.00 S31.00 Unspecified open wound of lower back and pelvis Non-Billable/Non-Specific Codes S31.000Unspecified open wound of lower back and pelvis without penetration into retroperitoneumS31.000A..., initial encounterS31.000D..., subsequent encounterS31.000S..., sequelaS31.001Unspecified open wound of lower back and pelvis with penetration into retroperitoneumS31.001A..., initial encounterS31.001D..., subsequent encounterS31.001S..., sequela