ICD-10-CM > S00-T88 > S20-S29 > S21 > S21.4 > S21.45 > S21.459 S21.459 Open bite of unspecified back wall of thorax with penetration into thoracic cavity Non-Billable/Non-Specific Codes S21.459A..., initial encounterS21.459D..., subsequent encounterS21.459S..., sequela