ICD-10-CM · Spine

M99.70

M99.70 identifies stenosis of the intervertebral foramina of the head region caused by connective tissue changes or disc encroachment — a biomechanical lesion classified under the M99 block rather than structural spinal stenosis (M48).

Verified May 8, 2026 · 3 sources ↓

Status: Billable
Chapter: 13
Related CPT: 11
Region: Spine

Drawn from CDCCMS

Documentation tips

What should appear in the chart to support M99.70.

Source · Editorial brief grounded in 3 cited references ↓

Specify 'head region' or 'occiput/C1-C2' explicitly in the clinical note — generic 'cervical' language defaults to M99.71, not M99.70.
Distinguish the mechanism: document connective tissue thickening or disc encroachment as the cause of foraminal narrowing, not osteophytes or subluxation, to justify M99.70 over M99.60.
Reference imaging (MRI or CT) findings that identify foraminal narrowing at the craniocervical level attributable to soft tissue or disc pathology, including slice level and degree of stenosis if graded.
If billing under a chiropractic or OMT encounter, confirm the LCD (e.g., CMS A56273) requires this code in the secondary position with an M99.0x somatic dysfunction code as primary.
Document conservative care history (prior manipulation, physical therapy, analgesics) to support medical necessity for ongoing or interventional management.

Related CPT procedures

Procedure codes commonly billed with M99.70. Linking the right diagnosis to the right procedure is what establishes medical necessity.

Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis

99203 $117.57

New patient office or outpatient visit requiring a medically appropriate history and/or examination with low-complexity medical decision-making, or 30–44 minutes of total provider time on the date of the encounter.

99204 $177.36

New patient office or outpatient visit requiring moderate medical decision making, or 45–59 minutes of total provider time on the date of the encounter.

99205 $236.81

New patient office or outpatient visit requiring high-complexity medical decision making, or 60–74 minutes of total time on the date of encounter.

99213 $95.19

Established patient office or outpatient visit requiring 20–29 minutes of total time or low-complexity medical decision-making.

99214 $135.61

Office visit for an established patient requiring moderate-complexity medical decision making (MDM), or 30–39 minutes of total provider time on the date of service.

99215 $192.39

Highest-level office or outpatient E/M visit for an established patient, qualifying via high-complexity medical decision making or 40–54 minutes of total provider time on the date of service.

98940 View procedure details

98941 View procedure details

98942 View procedure details

99202 View procedure details

99212 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M99.70 and adjacent codes.

Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓

Confusing M99.70 (connective tissue/disc foraminal stenosis, head region) with M99.60 (osseous/subluxation foraminal stenosis, head region) — the mechanism drives the code choice, not just the location.
Defaulting to M99.71 (cervical region) when documentation says 'cervical' but the clinical finding is at the occiput-C1-C2 level — the head region has its own distinct code.
Using M48.01 (spinal stenosis, occipito-atlanto-axial region) interchangeably with M99.70 — M48 codes reflect structural/degenerative stenosis; M99.70 reflects biomechanical/connective tissue pathology.
Leaving M99.70 as a standalone code without supporting symptom or radiculopathy codes, which can trigger medical necessity denials from payers requiring clinical context.

Clinical context

Source · Editorial summary grounded in 3 cited references ↓

M99.70 applies when connective tissue thickening or disc material narrows the intervertebral foramina at the craniocervical junction (occiput-C1-C2 region), restricting nerve root passage. It is distinct from osseous/subluxation foraminal stenosis (M99.60, same region) and from neural canal stenosis (M99.50). The underlying mechanism — connective tissue restriction or discogenic narrowing rather than bony overgrowth or subluxation — must be documented to justify this code over its siblings.

This code appears most frequently in chiropractic and osteopathic manipulative treatment (OMT) billing contexts, where CMS LCD policy (A56273) explicitly lists M99.70 as a supporting diagnosis for long-term chiropractic care. Orthopedic spine practices may assign it when imaging or clinical assessment confirms foraminal compromise at the head region attributable to disc or connective tissue pathology, and when the M48.0x (structural spinal stenosis) family does not accurately reflect the biomechanical nature of the finding.

Because M99.70 sits in the 'Biomechanical lesions, not elsewhere classified' block, it should not be used if a more specific structural diagnosis fully captures the condition. Pair it with symptom codes (e.g., cervicogenic headache, upper cervical radiculopathy) to build medical necessity, and sequence it appropriately — primary or secondary — per payer LCD requirements.

Sibling codes

Other billable codes under M99.7 (laterality / anatomic variants).

M99.78

Conn tiss and disc stenosis of intvrt foramina of rib cage

M99.72

Conn tiss and disc stenos of intvrt foramin of thor region

M99.77

Conn tiss and disc stenosis of intvrt foramina of up extrem

M99.74

Conn tiss and disc stenos of intvrt foramin of sacral region

M99.76

Conn tiss and disc stenosis of intvrt foramina of low extrm

M99.79

Conn tiss & disc stenos of intvrt foramin of abd and oth rgn

M99.71

Conn tiss and disc stenosis of intvrt foramin of cerv region

M99.73

Conn tiss and disc stenos of intvrt foramin of lumbar region

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 3 cited references ↓

01What distinguishes M99.70 from M99.60?

M99.60 is osseous and subluxation stenosis of the intervertebral foramina of the head region — bony or positional narrowing. M99.70 is the same location but caused by connective tissue or disc pathology. Document the mechanism to pick the right code.

02What distinguishes M99.70 from M48.01?

M48.01 (spinal stenosis, occipito-atlanto-axial region) covers structural degenerative stenosis. M99.70 belongs to the biomechanical lesion block and is used when connective tissue or disc changes — rather than classic degenerative overgrowth — are narrowing the foramen. Payer LCDs for chiropractic explicitly list M99.70; M48.01 falls outside that covered group.

03Can M99.70 be the primary diagnosis on a chiropractic claim?

Under most Medicare chiropractic LCDs (e.g., CMS A56273), an M99.0x segmental and somatic dysfunction code must be primary for spinal manipulation. M99.70 typically serves as a supporting secondary diagnosis documenting the underlying foraminal pathology.

04Is M99.70 used in orthopedic spine practice or only in chiropractic?

It can be used by any provider — orthopedic spine, neurosurgery, osteopathic, or chiropractic — when the clinical picture matches connective tissue or disc foraminal stenosis at the head region. However, it appears most frequently in chiropractic and OMT billing contexts where CMS LCDs explicitly support it.

05Does M99.70 require a laterality designation?

No. M99.70 has no laterality sub-digits — the code is complete as a 5-character billable code. Foraminal involvement on the left, right, or bilaterally is not further specified within this code; document side in the clinical note for completeness.

06What imaging supports M99.70?

MRI is the preferred modality to document soft-tissue or disc foraminal narrowing at the craniocervical junction. CT can supplement bony versus soft-tissue differentiation. Reference the specific level (e.g., C0-C1 foramen) and characterize the tissue type causing stenosis in the impression to align documentation with the code's specificity.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

01CDC ICD-10-CM Tabular List 2026
02
cms.gov
https://www.cms.gov/medicare-coverage-database/view/article.aspx?articleId=56273
03
cms.gov
https://www.cms.gov/files/document/fy-2026-icd-10-cm-coding-guidelines.pdf

Mira AI Scribe

Mira AI Scribe captures the clinician's documented region (head/craniocervical junction vs. cervical), the identified tissue type causing foraminal narrowing (connective tissue or disc vs. bone/subluxation), and any imaging reference supporting soft-tissue foraminal compromise at that level. This prevents miscoding to M99.60 (osseous mechanism) or M99.71 (wrong region), either of which can trigger a claim edit or audit flag on payer systems that cross-reference mechanism specificity.

See how Mira captures M99.70 documentation