ICD-10-CM 2027
ICD-10 code for thoracolumbar region flatback syndrome
From the official ICD-10-CM alphabetic index entry “Flatback syndrome › thoracolumbar region”. Page updated September 29, 2026.
About coding thoracolumbar region flatback syndrome
The ICD-10-CM code for thoracolumbar region flatback syndrome is M40.35 (Flatback syndrome, thoracolumbar region).
Within M40.3 (Flatback syndrome), M40.35 is specifically for Flatback syndrome, thoracolumbar region. Related codes cover site unspecified (M40.30), lumbar region (M40.36) and lumbosacral region (M40.37).
Code first: underlying disease.
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
Common questions about thoracolumbar region flatback syndrome ICD-10 codes
What is the ICD-10 code for thoracolumbar region flatback syndrome?
- M40.35 — Flatback syndrome, thoracolumbar region.
Is M40.35 billable?
- Yes. M40.35 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can M40.35 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict M40.35 as a principal diagnosis.
Is M40.35 a CC or MCC?
- No. M40.35 is neither a CC nor an MCC under MS-DRG v44.0.