ICD-10-CM · Other

M99.45

Narrowing of the neural canal in the pelvic region caused by abnormal connective tissue, classified as a biomechanical lesion under the M99 category.

Verified May 8, 2026 · 5 sources ↓

Status: Billable
Chapter: 13
Related CPT: 5
Region: Other

Drawn from CDCICD10DataAAPCCMSPainphysicianjournal

Documentation tips

What should appear in the chart to support M99.45.

Source · Editorial brief grounded in 5 cited references ↓

Specify 'pelvic region' explicitly in the clinical notes — documentation that only says 'sacral' or 'lumbar' will not support M99.45.
Identify the tissue type causing stenosis as connective tissue (e.g., ligamentous hypertrophy, fibrosis, scar tissue); osseous or disc etiology shifts the code to M99.35 or M99.55.
Include imaging findings (MRI or CT) that demonstrate neural canal narrowing in the pelvic region, including any reference to soft tissue encroachment.
If conservative care has been attempted, document the modalities used and duration — payers may require this to justify advanced imaging or interventional procedures linked to this diagnosis.
Note any associated neurological symptoms (radiculopathy, bladder/bowel involvement) that support the clinical significance of the stenosis.

Related CPT procedures

Procedure codes commonly billed with M99.45. Linking the right diagnosis to the right procedure is what establishes medical necessity.

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

27096 $175.69

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

72195 $227.46

MRI of the pelvis performed without contrast material, producing soft-tissue images of pelvic structures without intravenous dye administration.

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.

72197 View procedure details

98925 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M99.45 and adjacent codes.

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

Using M99.45 when documentation specifies sacral region — that maps to M99.44, not M99.45.
Selecting M99.45 when the stenosis is osseous in origin — osseous pelvic neural canal stenosis is M99.35.
Confusing M99.45 (neural canal stenosis) with M99.65 (connective tissue and disc stenosis of intervertebral foramina of pelvic region) — these are structurally distinct; canal stenosis and foraminal stenosis are not interchangeable.
Appending a 7th-character extension (A, D, S) to M99.45 — M99 codes do not carry 7th-character injury encounter designators.
Using a nonspecific parent code like M99.4 on a claim when M99.45 is documentable — M99.4 is a non-billable header code and will reject.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

M99.45 identifies connective tissue stenosis of the neural canal specifically localized to the pelvic region. It sits within the M99.4 subcategory (Connective tissue stenosis of neural canal) and is distinguished from adjacent codes by region: M99.44 covers the sacral region, M99.46 covers the lower extremity. The distinction between pelvic and sacral is clinically meaningful — do not use M99.45 when documentation specifies sacral involvement.

This code falls under M99 (Biomechanical lesions, not elsewhere classified), meaning it is appropriate when the stenosis mechanism is connective tissue-driven rather than osseous (M99.35), disc-related (M99.55), or subluxation-related (M99.25). If imaging or operative notes identify the causative tissue type as bone or disc, the corresponding M99.3x or M99.5x code applies instead. When the mechanism is unspecified, query the treating provider before defaulting to M99.45.

M99.45 is commonly encountered in osteopathic, chiropractic, and physiatry settings, and may appear alongside OMT procedure codes. It is also relevant to pelvic pain workups, sacroiliac joint dysfunction evaluations, and pre-operative documentation for pelvic decompression procedures. There are no 7th-character extensions required — M99 codes are not injury codes and do not use A/D/S designators.

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

M99.43

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

M99.44

Connective tissue stenosis of neural canal of sacral 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 M99.45 from M99.44?

M99.44 is connective tissue stenosis of the neural canal of the sacral region; M99.45 is the pelvic region. The treating provider must specify which anatomic region is affected — do not infer one from the other.

02Can M99.45 be used for osseous pelvic canal stenosis?

No. Osseous stenosis of the neural canal of the pelvic region is M99.35. M99.45 is reserved for connective tissue as the identified causative mechanism.

03Is M99.45 appropriate for foraminal stenosis in the pelvic region?

No. Foraminal stenosis (connective tissue and disc type) in the pelvic region maps to M99.65, not M99.45. Neural canal stenosis and intervertebral foraminal stenosis are coded separately in the M99 system.

04Does M99.45 require a 7th-character extension?

No. M99 codes are biomechanical lesion codes, not injury S-codes. There are no 7th-character extensions (A/D/S) for M99.45.

05Is M99.45 used in osteopathic or chiropractic billing?

Yes. M99.45 is within the M99 biomechanical lesions category, which is frequently paired with OMT and chiropractic manipulation procedure codes. It is a valid primary or secondary diagnosis in those contexts when pelvic connective tissue neural canal stenosis is documented.

06What ICD-9-CM code does M99.45 crosswalk from?

M99.45 crosswalks approximately from ICD-9-CM 724.09 (spinal stenosis, other region) — there is no exact one-to-one legacy equivalent given the increased specificity of ICD-10-CM's regional and tissue-type distinctions.

07Can M99.45 be coded alongside M48.4x spinal stenosis codes?

Potentially, if both conditions are independently documented and clinically distinct. M48.4x covers structural spinal stenosis while M99.45 is a biomechanical classification. Query the provider if the same anatomic finding is being described twice — dual coding the same stenosis under both categories is a common audit flag.

Sources & references

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

Mira AI Scribe

The Mira AI Scribe captures the anatomic region (pelvic), the identified tissue type causing canal compromise (connective tissue, e.g., ligamentous hypertrophy or fibrosis), and any supporting imaging findings showing neural canal narrowing. This prevents a downcode to a nonspecific biomechanical lesion or misassignment to the sacral or foraminal stenosis codes, both of which trigger payer scrutiny and potential claim rejection.

See how Mira captures M99.45 documentation