ICD-10-CM · Hip

M99.35

Osseous stenosis of the neural canal in the pelvic region caused by bony overgrowth or structural changes that narrow the canal and compress neural structures.

Verified May 8, 2026 · 5 sources ↓

Status: Billable
Chapter: 13
Related CPT: 6
Region: Hip

Drawn from CDCICD10DataAAPCCMSIlchiro

Documentation tips

What should appear in the chart to support M99.35.

Source · Editorial brief grounded in 5 cited references ↓

Document the precise anatomic region as 'pelvic' — distinguish from lumbar (L1–L5) or sacral segments so the 5th character is defensible on audit.
Record imaging findings explicitly: CT or MRI evidence of bony encroachment on the neural canal, including any measurements of canal diameter if available.
Note the neurological correlate — radiculopathy, neurogenic claudication, bowel/bladder symptoms — that links the osseous stenosis to the patient's presenting complaint.
If an underlying etiology (Paget disease, prior pelvic fracture, degenerative change) drives the osseous stenosis, document it separately so you can sequence codes correctly.
For chiropractic claims, confirm the treating provider has documented segmental dysfunction in the pelvic region alongside M99.35 to satisfy payer medical necessity edits.

Related CPT procedures

Procedure codes commonly billed with M99.35. Linking the right diagnosis to the right procedure is what establishes medical necessity.

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

72195 $227.46

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

72170 $28.06

Radiologic examination of the pelvis capturing one or two views, used to evaluate pelvic bones, sacrum, and coccyx for fractures, arthritis, or other structural abnormalities.

72190 $43.42

Radiologic examination of the pelvis requiring a minimum of three separate views, capturing the pelvic bones, hip joints, and surrounding structures.

27096 $175.69

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

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.

72197 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M99.35 and adjacent codes.

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

Using M99.35 when the stenosis is at the lumbar vertebral level (L1–L5) — that maps to M99.33 (lumbar) or spinal stenosis codes M48.06/M48.07, not the pelvic region code.
Defaulting to M99.35 when imaging reports say 'sacral canal stenosis' — that is M99.34 (sacral region), one digit up from pelvic.
Submitting M99.35 as the sole diagnosis without an accompanying symptom or functional code when payers require medical necessity justification beyond the biomechanical lesion alone.
Confusing osseous stenosis (M99.3x) with connective tissue stenosis (M99.5x) or intervertebral disc stenosis (M99.6x) of the same region — review the imaging report to confirm the stenosis mechanism is bony before assigning M99.35.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

M99.35 identifies bony (osseous) narrowing of the neural canal specifically at the pelvic region — sacrum, sacroiliac joints, and adjacent pelvic bony structures — as a biomechanical lesion. It sits under the M99.3x subgroup (osseous stenosis of neural canal), which runs from head (M99.30) through upper extremity (M99.37) by anatomic region. The 5th character '5' designates the pelvic region; do not use this code for lumbar (M99.33) or sacral (M99.34) stenosis if the documentation specifies those segments.

This code appears most often in chiropractic, physiatry, and orthopedic spine practices when imaging — CT or MRI — demonstrates bony narrowing of the pelvic neural canal and the treating provider attributes the patient's pain, radiculopathy, or neurogenic symptoms to that structural finding. Some payers (notably BCBS Illinois) have required M99-category codes alongside manipulation procedure codes to justify medical necessity; confirm payer-specific requirements before submitting.

M99.35 is a biomechanical lesion code, not a primary structural disease code. If a more specific underlying etiology is documented — such as Paget disease, degenerative spondylolisthesis, or post-traumatic deformity narrowing the canal — code the underlying condition first and use M99.35 as an additional code only if it adds clinical specificity not captured by the primary code. Do not use M99.35 as a stand-alone substitute for lumbar spinal stenosis (M48.06, M48.07) when the stenosis is clearly at the lumbar vertebral level.

Sibling codes

Other billable codes under M99.3 (laterality / anatomic variants).

M99.39

Osseous stenosis of neural canal of abdomen and oth regions

M99.30

Osseous stenosis of neural canal of head region

M99.37

Osseous stenosis of neural canal of upper extremity

M99.33

Osseous stenosis of neural canal of lumbar region

M99.32

Osseous stenosis of neural canal of thoracic region

M99.38

Osseous stenosis of neural canal of rib cage

M99.31

Osseous stenosis of neural canal of cervical region

M99.34

Osseous stenosis of neural canal of sacral region

Frequently asked questions

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

01What distinguishes M99.35 (pelvic) from M99.34 (sacral) and M99.33 (lumbar)?

The 5th character designates the anatomic region: '3' = lumbar, '4' = sacral, '5' = pelvic. Use the provider's documentation and imaging report to assign the correct region. When the stenosis spans multiple levels, code each applicable region separately.

02Can M99.35 be used as a primary diagnosis on an orthopedic or physiatry claim?

Yes — it is a fully billable code and can be listed as the primary diagnosis when osseous neural canal stenosis of the pelvic region is the condition driving the encounter. Add symptom codes (e.g., radiculopathy, pelvic pain) as secondary if they provide additional clinical context required by the payer.

03Is M99.35 appropriate for chiropractic claims, and do payers require additional codes?

M99.35 is used in chiropractic billing when osseous pelvic neural canal stenosis is documented. Some payers, including BCBS Illinois, have required concurrent segmental dysfunction codes (M99.05 for pelvic region) alongside M99 stenosis codes to support manipulation medical necessity. Verify payer-specific edit requirements before submitting.

04Does M99.35 require a 7th character extension?

No. M99 codes are musculoskeletal biomechanical lesion codes in Chapter 13 and do not use 7th-character extensions. Those extensions (A/D/S) apply to injury codes in Chapter 19 (S- and T-codes).

05When should M99.35 be secondary rather than primary?

When a documented underlying condition — such as Paget disease, degenerative joint disease, or post-traumatic pelvic deformity — is the root cause of the bony narrowing, sequence that condition first. M99.35 then adds specificity about the structural consequence at the neural canal.

06What imaging is typically cited to support M99.35?

CT or MRI of the pelvis demonstrating bony encroachment on the neural canal is the standard evidentiary basis. Plain radiographs showing osteophyte formation or bony deformity at the pelvic neural canal can supplement but are generally less definitive than cross-sectional imaging.

Sources & references

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

Mira AI Scribe

Mira's AI scribe captures the anatomic region (pelvic vs. lumbar vs. sacral), the stenosis mechanism (bony overgrowth, osteophyte, post-traumatic deformity), imaging modality and findings, and any neurological symptoms tied to the narrowing. That granularity prevents a drop to an unspecified biomechanical lesion code and defends the pelvic-region 5th character against payer queries.

See how Mira captures M99.35 documentation