Narrowing of the sacral neural canal caused by positional or segmental subluxation of sacral vertebral structures, classified as a biomechanical lesion under M99.
Verified May 8, 2026 · 5 sources ↓
- Status
- Billable
- Chapter
- 13
- Related CPT
- 10
- Region
- Spine
Documentation tips
What should appear in the chart to support M99.24.
Source · Editorial brief grounded in 5 cited references ↓
- Specify 'sacral region' or 'sacral segment' by name — M99.24 covers sacral, sacrococcygeal, and sacroiliac subluxation-stenosis presentations per the Alphabetic Index.
- Document the subluxation mechanism explicitly (e.g., segmental subluxation, positional instability) to distinguish M99.24 from osseous (M99.34), disc (M99.54), or connective tissue (M99.44) stenosis at the same level.
- Record neurological findings referable to sacral nerve roots (S1–S5): dermatomal sensory loss, bowel/bladder changes, lower extremity weakness — these support medical necessity for NCS/EMG under CMS Article A56619.
- Note any imaging findings: MRI or CT evidence of neural canal narrowing at the sacrum, foraminal compromise, or sacral subluxation on dynamic views strengthens coding and audit defense.
- Confirm that no more specific code (M48.08 sacral/sacrococcygeal spinal stenosis, sacral fracture, or disc pathology) better captures the primary structural diagnosis before assigning M99.24, per the M99 category note.
Related CPT procedures
Procedure codes commonly billed with M99.24. Linking the right diagnosis to the right procedure is what establishes medical necessity.
Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis
Common coding pitfalls
The recurring mistakes coders make with M99.24 and adjacent codes.
Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓
- Defaulting to M48.08 (spinal stenosis, sacral and sacrococcygeal region) when the mechanism is explicitly subluxation-driven — M99.24 is the correct code when subluxation is the documented cause of canal narrowing and no more specific code applies.
- Using M99.24 when a more specific diagnosis (sacral disc herniation, sacral fracture, osseous stenosis M99.34) is documented — the M99 category note prohibits its use if the condition can be classified elsewhere.
- Conflating M99.24 with M99.25 (pelvic region) or M99.64 (osseous and subluxation stenosis of intervertebral foramina, sacral region) — foraminal stenosis has its own separate code; M99.24 is strictly neural canal, not foraminal.
- Omitting the subluxation mechanism in documentation and submitting M99.24 anyway — payers auditing against clinical notes that describe only 'sacral stenosis' without subluxation attribution will downcode or deny.
Clinical context
Source · Editorial summary grounded in 5 cited references ↓
M99.24 applies when documented subluxation of sacral segments mechanically compresses or narrows the neural canal at the sacral level — a biomechanical mechanism distinct from osseous stenosis (M99.34), connective tissue stenosis (M99.44), or intervertebral disc stenosis (M99.54) at the same region. The M99 category is reserved for conditions that cannot be classified elsewhere; if a more specific structural diagnosis (e.g., spinal stenosis M48.08, sacral fracture, or disc herniation) accounts for the narrowing, that code takes priority.
In orthopedic and chiropractic-adjacent practice, M99.24 is most often applied when imaging or clinical assessment identifies sacral segmental subluxation with associated neural canal compromise producing sacral radiculopathy, bowel/bladder dysfunction, or lower extremity neurological symptoms referable to sacral nerve roots. The ICD-9-CM crosswalk maps M99.24 to the legacy code 724.09 (spinal stenosis, other region other than cervical), reflecting its functional overlap with stenotic conditions of the lower spine.
The Alphabetic Index routes sacrococcygeal and sacroiliac subluxation-stenosis presentations to M99.24 as well, so document sacral localization explicitly to support this code. CMS recognizes M99.24 as a covered diagnosis supporting medical necessity for nerve conduction studies and electromyography (NCS/EMG), making precise documentation of sacral localization and the subluxation mechanism directly relevant to procedural reimbursement.
Sibling codes
Other billable codes under M99.2 (laterality / anatomic variants).
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 5 cited references ↓
01When should I use M99.24 instead of M48.08?
02Does M99.24 cover sacrococcygeal and sacroiliac subluxation-stenosis?
03Can M99.24 be used as a primary diagnosis for NCS/EMG billing?
04What is the ICD-9-CM crosswalk for M99.24?
05Is M99.24 appropriate when both subluxation and osseous factors cause sacral canal stenosis?
06Does M99.24 require a 7th character extension?
Sources & references
Editorial content was developed using the following public sources. Last verified May 8, 2026.
- 01CDC ICD-10-CM Tabular List 2026
- 02icd10data.comhttps://www.icd10data.com/ICD10CM/Codes/M00-M99/M99-M99/M99-/M99.24
- 03cms.govhttps://www.cms.gov/medicare-coverage-database/view/article.aspx?articleId=56619&ver=30
- 04painphysicianjournal.comhttps://www.painphysicianjournal.com/current/pdf/MTUwMQ%3D%3D/63
- 05aapc.comhttps://www.aapc.com/codes/icd-10-codes/M99.24
Mira AI Scribe
Mira captures the sacral region localization, the subluxation mechanism, and associated neurological findings (dermatomal deficits, bowel/bladder involvement, radicular pain pattern) from the encounter note to support M99.24. This prevents downcoding to the nonspecific M99.29 or misassignment to M48.08, and preserves medical necessity documentation for NCS/EMG procedures covered under CMS Article A56619.
See how Mira captures M99.24 documentation