ICD-10-CM · Spine

M99.74

Narrowing of the intervertebral foramina in the sacral region caused by connective tissue changes, disc material, or both — classified as a biomechanical lesion under the M99 category.

Verified May 8, 2026 · 4 sources ↓

Status: Billable
Chapter: 13
Related CPT: 9
Region: Spine

Drawn from CDCICD10DataAAPC

Documentation tips

What should appear in the chart to support M99.74.

Source · Editorial brief grounded in 4 cited references ↓

Provider must explicitly name the sacral region (or sacrococcygeal/sacroiliac sub-site) — 'lower spine' or 'lumbosacral' without further specificity defaults to a less precise code.
Identify the stenotic mechanism: connective tissue fibrosis, disc material, or both. M99.74 covers either or a combination, but documentation should support why a more specific structural code (e.g., M51.1x for disc herniation) was not used instead.
Record imaging findings that confirm foraminal narrowing at the sacral level — MRI signal change, CT foraminal diameter measurement, or myelogram findings at S1–S4.
Note any prior conservative care (physical therapy, injections, manipulation) to support medical necessity, especially for pre-authorization or surgical referral encounters.
If sacroiliac or sacrococcygeal involvement is the sub-site, document it explicitly so reviewers understand why M99.74 applies rather than M99.75 (pelvic region).

Related CPT procedures

Procedure codes commonly billed with M99.74. Linking the right diagnosis to the right procedure is what establishes medical necessity.

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

72148 $191.72

Non-contrast MRI of the lumbar spine used to evaluate disc pathology, spinal stenosis, nerve root compression, and other structural abnormalities without administration of contrast material.

72158 $318.31

MRI of the lumbar spinal canal and its contents performed first without contrast, then repeated after contrast administration for enhanced visualization.

72100 $40.42

Radiologic examination of the lumbosacral spine capturing two or three views, used to evaluate the lumbar vertebrae and sacrum for injury, degeneration, or structural abnormality.

72120 $42.09

Radiologic examination of the lumbosacral spine using bending views only, minimum of four views, to assess spinal flexibility and alignment.

27096 $175.69

Injection into the sacroiliac joint with fluoroscopic or CT image guidance, including arthrography when performed.

63030 $898.15

Single-interspace lumbar laminotomy with nerve root decompression, including partial facetectomy, foraminotomy, and/or herniated disc excision performed via open surgical technique.

97110 $29.06

Therapeutic exercise billed per 15-minute unit, targeting strength, endurance, range of motion, or flexibility with direct one-on-one patient contact.

62323 View procedure details

98941 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M99.74 and adjacent codes.

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

Using M99.74 when a classifiable structural diagnosis exists: the M99 tabular note requires you to code the definitive diagnosis (e.g., herniated disc, spondylolisthesis) instead — M99.74 is a residual/biomechanical category.
Confusing foraminal stenosis (M99.74) with neural canal stenosis: connective tissue or disc stenosis of the sacral neural canal is M99.44 (connective tissue) or M99.54 (disc) — the foramen and the canal are anatomically and code-set distinct.
Defaulting to M99.74 for any sacral radiculopathy without imaging or clinical evidence of foraminal narrowing — this creates an unsupported diagnosis that will not survive audit.
Coding M99.74 when the stenosis is in the pelvic region foramen rather than the sacral segment; that encounter maps to M99.75.
Omitting a laterality or nerve root descriptor in the clinical note, which weakens medical necessity documentation even though the code itself does not require it.

Clinical context

Source · Editorial summary grounded in 4 cited references ↓

M99.74 captures foraminal stenosis at the sacral level when the mechanism is connective tissue fibrosis, disc encroachment, or a combination of both. This distinguishes it from osseous foraminal stenosis (M99.34, bony overgrowth) and subluxation-driven foraminal stenosis (M99.24). The sacral intervertebral foramina transmit sacral nerve roots; stenosis here can produce lower sacral radiculopathy, pelvic floor symptoms, or coccygeal pain patterns. The M99 category carries a critical tabular note: use M99.74 only if the condition cannot be classified elsewhere. If a definitive structural diagnosis is established — such as a herniated disc (M51.1x) or spondylolisthesis — code that condition first and evaluate whether M99.74 adds clinical specificity or becomes redundant.

The index cross-references sacrococcygeal and sacroiliac foraminal stenosis of connective tissue or disc origin to M99.74, so encounters involving those sub-sites within the sacral region land on the same code. Note the distinction from M99.75 (pelvic region foraminal stenosis) — if documentation specifies the pelvic foramen rather than the sacral segment, the correct code shifts to M99.75.

M99.74 appears frequently in chiropractic and osteopathic encounter billing (OMT claims), physical medicine contexts, and pain management workups for sacral nerve root compression. Orthopedic coders encounter it in spine surgery pre-authorization documentation and in evaluation of patients presenting with S1–S4 radicular patterns not explained by more specific structural pathology.

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

M99.70

Conn tiss and disc stenosis of intvrt foramin of head region

M99.77

Conn tiss and disc stenosis of intvrt foramina of up extrem

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 4 cited references ↓

01When should I use M99.74 instead of a disc herniation code like M51.17?

Use M99.74 only when the foraminal stenosis cannot be attributed to a classifiable structural lesion. If imaging and clinical documentation support a sacral disc herniation as the stenotic cause, M51.17 (or applicable disc degeneration code) is the correct primary diagnosis. M99.74 is a biomechanical residual — the tabular note explicitly restricts its use to conditions not classifiable elsewhere.

02Does M99.74 cover both sacroiliac and sacrococcygeal foraminal stenosis?

Yes. The ICD-10-CM Alphabetic Index routes connective tissue or disc stenosis of the sacral, sacrococcygeal, and sacroiliac foramina to M99.74. Document the specific sub-site in the note so reviewers understand the anatomical basis.

03What is the difference between M99.74 and M99.44 or M99.54?

M99.44 is connective tissue stenosis of the sacral neural canal; M99.54 is disc stenosis of the sacral neural canal. M99.74 applies to the intervertebral foramen — the opening through which nerve roots exit — not the central canal. Use the correct anatomical structure as documented by imaging.

04Is M99.74 appropriate for chiropractic or OMT encounter billing?

Yes, M99.74 is used in chiropractic and osteopathic manipulative treatment billing when foraminal stenosis of connective tissue or disc origin at the sacral level is the documented diagnosis. Ensure the diagnosis is supported by clinical findings and not superseded by a more specific structural code.

05What imaging documentation best supports M99.74?

MRI demonstrating foraminal narrowing at the sacral level with signal change suggesting disc or connective tissue encroachment is the strongest support. CT measurements of foraminal diameter or myelogram findings at S1–S4 are also acceptable. Document the specific level and the radiologist's or provider's interpretation of the stenotic tissue type.

06Can M99.74 be used as a primary diagnosis on a surgical pre-authorization?

It can appear in pre-authorization documentation, but payers will scrutinize whether a more specific structural code should lead. If the surgical indication is foraminal decompression driven by connective tissue or disc stenosis at the sacral level without a classifiable primary structural diagnosis, M99.74 may appropriately lead — pair it with clinical and imaging documentation that explains why no more specific code applies.

Sources & references

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

01CDC ICD-10-CM Tabular List 2026 (effective Oct 1, 2025)
02
icd10data.com
https://www.icd10data.com/ICD10CM/Codes/M00-M99/M99-M99/M99-/M99.74
03
aapc.com
https://www.aapc.com/codes/icd-10-codes/M99.74
04
icd10data.com
https://www.icd10data.com/ICD10CM/Codes/M00-M99/M99-M99/M99-

Mira AI Scribe

Mira AI Scribe captures the sacral region localization, the provider's characterization of the stenotic mechanism (connective tissue, disc, or combined), and any imaging findings documenting foraminal narrowing at S1–S4. It also flags whether a more specific structural diagnosis (herniated disc, spondylolisthesis) was ruled out or addressed separately — preventing the most common audit vulnerability for M99.74, which is applying a biomechanical residual code when a classifiable structural code should lead.

See how Mira captures M99.74 documentation