ICD-10 Code for Synostosis
Also indexed as (congenital)
The ICD-10-CM code for synostosis is Q78.8 — Other specified osteochondrodysplasias. This is the code the Alphabetic Index gives for synostosis with no further qualifier, valid for FY2027 (October 1, 2026 – September 30, 2027).
Q78.8 is billable but unspecified. If the documentation names a type, site or cause, one of the more specific codes below is likely expected.
Which synostosis code should you use?
The Alphabetic Index lists 3 codes under Synostosis. Which one applies depends on the qualifier documented in the record — the type, site, cause, or associated condition. Find the qualifier below, then verify the code in the Tabular List before using it.
Index terms and codes are reproduced from the official ICD-10-CM FY2027 release. The Alphabetic Index is a finding aid — a code must always be verified in the Tabular List before it is reported. Data sources