ICD-10-CM · Spine

M99.55

Narrowing of the neural canal in the pelvic region caused by intervertebral disc pathology, classified under biomechanical lesions of the musculoskeletal system.

Verified May 8, 2026 · 5 sources ↓

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

Drawn from CDCICD10DataAAPCFindacodeCMS

Documentation tips

What should appear in the chart to support M99.55.

Source · Editorial brief grounded in 5 cited references ↓

Provider must document 'pelvic region' as the anatomic site — 'sacral' maps to M99.54 and 'lumbar' maps to M99.53; do not use M99.55 interchangeably with either.
Note must support a biomechanical disc etiology for the neural canal stenosis; if pathology is degenerative or structural, M48.0x or M51.x series may be more appropriate.
Imaging findings (MRI or CT) identifying disc-related narrowing of the pelvic neural canal strengthen medical necessity and support this code against payer audit.
Document associated neurological or radicular symptoms referable to the pelvic region to justify clinical significance and support necessity for any ordered imaging or interventional procedure.
If multiple spinal regions are involved, assign a separate M99.5x code for each documented region rather than defaulting to an unspecified code.

Related CPT procedures

Procedure codes commonly billed with M99.55. 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.

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.

72196 View procedure details

72197 View procedure details

72198 View procedure details

64450 View procedure details

97001 View procedure details

98940 View procedure details

98941 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M99.55 and adjacent codes.

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

Confusing pelvic region (M99.55) with sacral region (M99.54) — these are distinct 6th-character designations; 'sacral' and 'pelvic' are not interchangeable in the M99.5x series.
Defaulting to M99.55 when lumbar disc stenosis is the actual finding — lumbar maps to M99.53, not M99.55.
Assigning M99.55 for documented degenerative disc disease or herniation; those conditions belong in the M51.x series, not the biomechanical M99 category.
Using the parent code M99.5 (non-billable) instead of the fully specified M99.55 — M99.5 does not pass claim edits as it lacks the required 6th character.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

M99.55 captures intervertebral disc stenosis of the neural canal specifically localized to the pelvic region. This code sits under the M99.5x family (Intervertebral disc stenosis of neural canal), which maps region by the 6th character: M99.50 (head), M99.51 (cervical), M99.52 (thoracic), M99.53 (lumbar), M99.54 (sacral), M99.55 (pelvic), and M99.59 (abdomen and other). The pelvic designation is distinct from the sacral (M99.54) and lumbar (M99.53) designations — use M99.55 only when documentation explicitly identifies the pelvic region as the site of disc-mediated canal narrowing.

This code falls under the M99 category of biomechanical lesions not elsewhere classified, which is commonly used in chiropractic, osteopathic, and physiatric practice, but is also valid in orthopedic settings when the clinical picture involves mechanical disc-related compromise of the neural canal at the pelvis. It does not capture frank disc herniation (see M51.x series) or spinal stenosis coded as a structural disease process (M48.0x) — M99.55 is specifically for biomechanical lesion classification. Confirm the treating provider's documentation explicitly supports a biomechanical etiology and pelvic regional localization before assigning this code.

Sibling codes

Other billable codes under M99.5 (laterality / anatomic variants).

M99.59

Intvrt disc stenos of neural canal of abd and oth regions

M99.57

Intervertebral disc stenosis of neural canal of up extrem

M99.56

Intervertebral disc stenosis of neural canal of low extrm

M99.54

Intvrt disc stenosis of neural canal of sacral region

M99.58

Intervertebral disc stenosis of neural canal of rib cage

M99.50

Intervertebral disc stenosis of neural canal of head region

M99.51

Intvrt disc stenosis of neural canal of cervical region

M99.52

Intvrt disc stenosis of neural canal of thoracic region

Frequently asked questions

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

01What is the difference between M99.55 and M99.54?

M99.54 is intervertebral disc stenosis of the neural canal of the sacral region; M99.55 is the same pathology localized to the pelvic region. The treating provider must document which region is affected — coders should not infer one from the other.

02Can M99.55 be used for degenerative disc disease causing canal narrowing at the pelvis?

No. M99.55 is a biomechanical lesion code (M99 category). Degenerative or structural disc pathology maps to the M51.x series. Use M99.55 only when the provider documents a biomechanical etiology.

03Is M99.55 valid for orthopedic practice billing, or only chiropractic/osteopathic?

M99.55 is a valid ICD-10-CM billable code for any provider who documents the applicable diagnosis. It is commonly used in chiropractic and osteopathic contexts but is not restricted to those specialties — orthopedic coders may assign it when documentation supports it.

04What happens if the provider documents 'pelvic and sacral' disc stenosis?

Assign both M99.55 and M99.54. Code each documented region separately within the M99.5x family rather than collapsing to a single unspecified code.

05Does M99.55 require a 7th character?

No. M99.55 is a 5-character code under Chapter 13 (Musculoskeletal). The 7th-character extension convention applies to injury S-codes, not M-codes.

06Which imaging studies best support M99.55 for payer documentation purposes?

MRI of the pelvis or lumbosacral spine with documented findings of disc-mediated narrowing of the neural canal at the pelvic level is the strongest support. CT with contrast is an alternative when MRI is contraindicated. Document the specific finding (e.g., disc protrusion, disc height loss with canal compromise) and the regional localization in the radiology report.

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 provider's explicit regional designation (pelvic vs. sacral vs. lumbar), the biomechanical nature of the disc pathology, any neurological symptoms referable to that region, and supporting imaging findings such as MRI-documented neural canal narrowing. Capturing this specificity prevents downcoding to a non-billable parent code (M99.5) or miscoding to an adjacent region like M99.54 (sacral), either of which can trigger a claim rejection or audit flag.

See how Mira captures M99.55 documentation