ICD-10-CM > M00-M99 > M45-M49 > M48 > M48.5 > M48.51 M48.51 Collapsed vertebra, not elsewhere classified, occipito-atlanto-axial region Non-Billable/Non-Specific Codes M48.51XA..., initial encounter for fractureM48.51XD..., subsequent encounter for fracture with routine healingM48.51XG..., subsequent encounter for fracture with delayed healingM48.51XS..., sequela of fracture