ICD-10-CM · Spine

M99.44

Narrowing of the sacral neural canal caused by abnormal connective tissue — fibrosis, ligamentous hypertrophy, or other non-osseous soft-tissue changes — that encroaches on neural structures at the sacral level.

Verified May 8, 2026 · 5 sources ↓

Status: Billable
Chapter: 13
Related CPT: 7
Region: Spine

Drawn from CDCICD10DataCMSNIH

Documentation tips

What should appear in the chart to support M99.44.

Source · Editorial brief grounded in 5 cited references ↓

Explicitly state 'sacral region' in the clinical note — M99.44 is site-specific and cannot be inferred from general low back or pelvic descriptions.
Identify the tissue type causing stenosis: document 'fibrosis,' 'ligamentous hypertrophy,' or 'connective tissue thickening' to distinguish M99.44 from osseous stenosis (M99.34) or disc stenosis (M99.54).
Record imaging findings — MRI signal changes, ligamentum flavum thickening, or post-surgical fibrosis visible at the sacral canal level — to support medical necessity.
Note any prior sacral surgery or injections if fibrotic scar tissue is the suspected mechanism; payers may require this context to justify the diagnosis.
Confirm that no more specific ICD-10-CM code covers the underlying cause before assigning M99.44, per the M99 category exclusion note.

Related CPT procedures

Procedure codes commonly billed with M99.44. Linking the right diagnosis to the right procedure is what establishes medical necessity.

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

63011 $1,010.71

Laminectomy of one or two sacral vertebral segments to explore or decompress the spinal cord and/or cauda equina — without facetectomy, foraminotomy, or discectomy.

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.

63042 $1,219.80

Lumbar laminotomy or hemilaminectomy performed as a reexploration at a single interspace, including nerve root decompression with partial facetectomy, foraminotomy, and/or herniated disc excision at a previously operated level.

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.

72295 View procedure details

98925 View procedure details

98926 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M99.44 and adjacent codes.

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

Assigning M99.44 when a more specific code exists — degenerative lumbar/sacral conditions (M47.816, M51.17) or post-procedural adhesions must be coded first; M99 codes are residual by definition.
Confusing M99.44 (connective tissue stenosis, sacral neural canal) with M99.34 (osseous stenosis, sacral neural canal) — the mechanism documented in the note must drive code selection, not just the region.
Using the parent code M99.4 on a claim — it is non-billable; M99.44 is the required billable child code for the sacral site.
Conflating the sacral neural canal with the sacral intervertebral foramina — foraminal connective tissue stenosis at the sacrum codes to M99.74, not M99.44.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

M99.44 classifies connective tissue-mediated stenosis of the neural canal specifically at the sacral region. Unlike osseous stenosis (M99.34), which involves bony encroachment, this code targets soft-tissue pathology — thickened ligaments, fibrotic scar tissue, or hypertrophied connective tissue — as the primary mechanism compressing sacral nerve roots or the cauda equina at that level. It sits within the M99.4x family of connective tissue neural canal stenosis codes, which span the head through abdomen; sacral is the 4th-site subcode (M99.44).

The M99 category carries a critical instructional note: use these biomechanical lesion codes only when the condition cannot be classified elsewhere. If the stenosis is attributable to a more specific pathology — degenerative disc disease, spondylolisthesis, a neoplasm, or a post-surgical fibrosis with its own code — assign the more specific code first or instead. M99.44 is appropriate when the connective tissue stenosis is documented as the primary or standalone finding without a more specific underlying etiology already captured by another code.

This code appears in osteopathic, chiropractic, and orthopedic spine contexts. It is used by osteopathic physicians billing OMT to sacral regions, spine surgeons documenting preoperative diagnoses for sacral decompression, and physiatrists managing sacral radiculopathy driven by soft-tissue canal narrowing. Verify that the operative or clinical note explicitly names the sacral region and identifies connective tissue (not bone or disc) as the stenotic mechanism before assigning M99.44.

Sibling codes

Other billable codes under M99.4 (laterality / anatomic variants).

M99.48

Connective tissue stenosis of neural canal of rib cage

M99.40

Connective tissue stenosis of neural canal of head region

M99.45

Connective tissue stenosis of neural canal of pelvic region

M99.43

Connective tissue stenosis of neural canal of lumbar region

M99.47

Connective tiss stenosis of neural canal of upper extremity

M99.42

Connective tiss stenosis of neural canal of thoracic region

M99.46

Connective tiss stenosis of neural canal of lower extremity

M99.49

Conn tiss stenos of neural canal of abdomen and oth regions

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01What distinguishes M99.44 from M99.34?

M99.34 is osseous stenosis of the sacral neural canal — bony encroachment. M99.44 is connective tissue stenosis — soft-tissue pathology such as fibrosis or ligamentous hypertrophy. The operative or imaging report must name the stenotic tissue type to justify one over the other.

02Can M99.44 be used as a primary diagnosis for surgical decompression?

Yes, if connective tissue stenosis of the sacral neural canal is the operative indication and no more specific ICD-10-CM code (e.g., a degenerative disc or spondylolisthesis code) captures the pathology. The M99 category note requires you to rule out more specific codes first.

03Is M99.44 valid for chiropractic and OMT billing?

Yes. M99-series codes are used for OMT and chiropractic diagnoses. M99.44 is billable and appropriate when a chiropractor or osteopathic physician documents connective tissue neural canal stenosis at the sacral level as the basis for treatment.

04What is the difference between M99.44 and M99.74?

M99.44 describes stenosis of the sacral neural canal itself. M99.74 describes connective tissue and disc stenosis of the sacral intervertebral foramina — the exit points for nerve roots. Canal versus foraminal location must be specified in documentation.

05Does M99.44 require a 7th character?

No. M99.44 is a 5-character M-code. The 7th-character A/D/S extension applies to injury S-codes, not M-codes. M99.44 is complete as coded.

06Should I code M99.44 alongside a lumbar stenosis code if both levels are affected?

Yes. ICD-10-CM Chapter 13 guidelines instruct coders to assign multiple codes when more than one site is involved and no combination code exists. Use M99.43 for lumbar and M99.44 for sacral if both are documented.

07What imaging supports M99.44 in an audit?

MRI is the standard — look for ligamentum flavum thickening, epidural fibrosis, or other soft-tissue changes narrowing the sacral canal. Document the specific finding and level in the impression; vague 'stenosis' without tissue characterization weakens the code selection.

Sources & references

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

Mira AI Scribe

Mira captures the treating provider's explicit documentation of the sacral region, the connective tissue mechanism (e.g., fibrosis, ligamentous hypertrophy), and supporting imaging findings such as MRI-confirmed ligamentum flavum thickening or post-surgical fibrotic change at the sacral canal. This prevents downcoding to the unspecified biomechanical lesion level and blocks audit flags triggered by assigning M99.44 when a more specific degenerative or post-procedural code should lead.

See how Mira captures M99.44 documentation