ICD-10-CM > S00-T88 > S20-S29 > S21 > S21.2 > S21.25 > S21.259 S21.259 Open bite of unspecified back wall of thorax without penetration into thoracic cavity Non-Billable/Non-Specific Codes S21.259A..., initial encounterS21.259D..., subsequent encounterS21.259S..., sequela