ICD-10-CM > S00-T88 > S30-S39 > S31 > S31.0 > S31.05 S31.05 Open bite of lower back and pelvis Non-Billable/Non-Specific Applicable To Bite of lower back and pelvis NOS Type 1 Excludes superficial bite of lower back and pelvis (S30.860, S30.870) Codes S31.050Open bite of lower back and pelvis without penetration into retroperitoneumS31.050A..., initial encounterS31.050D..., subsequent encounterS31.050S..., sequelaS31.051Open bite of lower back and pelvis with penetration into retroperitoneumS31.051A..., initial encounterS31.051D..., subsequent encounterS31.051S..., sequela