Lateral spinal curvature in the lumbar region that develops as a direct consequence of an underlying neuromuscular disorder, such as cerebral palsy, muscular dystrophy, or spina bifida.
Verified May 8, 2026 · 6 sources ↓
- Status
- Billable
- Chapter
- 13
- Related CPT
- 15
- Region
- Spine
Documentation tips
What should appear in the chart to support M41.46.
Source · Editorial brief grounded in 6 cited references ↓
- Name the underlying neuromuscular condition explicitly in the note — e.g., 'lumbar scoliosis secondary to cerebral palsy' — so the required secondary code is unambiguous and audit-defensible.
- Record the Cobb angle and apex vertebral level from standing full-spine radiographs; payers and surgical precertification reviewers expect this measurement to substantiate severity.
- Document pelvic obliquity if present — it is a hallmark of neuromuscular scoliosis and supports medical necessity for pelvic fixation instrumentation codes.
- Specify the lumbar region by name in the assessment; 'lumbar' distinguishes M41.46 from adjacent codes M41.45 (thoracolumbar) and M41.47 (lumbosacral).
- If the curve crosses two regions, document the apex location so the single most-specific regional code can be selected rather than defaulting to an unspecified site code.
Related CPT procedures
Procedure codes commonly billed with M41.46. Linking the right diagnosis to the right procedure is what establishes medical necessity.
Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis
Common coding pitfalls
The recurring mistakes coders make with M41.46 and adjacent codes.
Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓
- Assigning M41.46 without a secondary code for the underlying neuromuscular condition violates the M41.4 'Code also' instruction — claims may deny or be flagged on audit.
- Using M41.46 for idiopathic lumbar scoliosis discovered in an adult with a coincidental neuromuscular diagnosis; the etiology must be causal, not coincidental.
- Defaulting to M41.40 (site unspecified) when the physician documents the lumbar region — M41.46 is billable and more specific; use it.
- Confusing the lumbar region apex with a thoracolumbar or lumbosacral apex — review imaging to confirm the correct regional code before assigning.
- Applying M41.46 when the scoliosis is postradiation (M96.5) or postprocedural (M96.89) — both are Excludes2 to M41 and require their own code categories.
Clinical context
Source · Editorial summary grounded in 6 cited references ↓
M41.46 applies when lumbar scoliosis is causally linked to a neuromuscular condition — not idiopathic or structural. The curve originates from abnormal muscle tone, weakness, or paralysis driven by the underlying neurological or muscular disease. Common driver conditions include cerebral palsy, Friedreich's ataxia, poliomyelitis, muscular dystrophy, and spina bifida. Per the M41.4 parent code annotation, you must also code the underlying condition — M41.46 alone is incomplete without it.
Distinguish M41.46 from adjacent categories before assigning it. Postradiation scoliosis goes to M96.5. Postprocedural scoliosis goes to M96.89. Congenital scoliosis NOS maps to Q67.5 and congenital scoliosis due to bony malformation maps to Q76.3 — all are Excludes1 to M41. If the curve spans both the thoracic and lumbar spine, consider M41.45 (thoracolumbar) or M41.47 (lumbosacral) based on the apex of curvature documented on imaging.
For the lumbar region specifically, the Cobb angle measurement and apex vertebral level should be documented on standing full-spine radiographs. Neuromuscular curves frequently exhibit larger Cobb angles and greater pelvic obliquity than idiopathic curves, which affects surgical planning codes and justifies medical necessity for more extensive imaging and instrumentation. Document the underlying diagnosis explicitly — payers will audit for the secondary code linkage.
Sibling codes
Other billable codes under M41.4 (laterality / anatomic variants).
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 6 cited references ↓
01Do I need to code the underlying neuromuscular condition alongside M41.46?
02How do I choose between M41.46 (lumbar), M41.45 (thoracolumbar), and M41.47 (lumbosacral)?
03Can M41.46 be used for a patient whose lumbar scoliosis followed radiation therapy?
04Is M41.46 appropriate when the neuromuscular diagnosis is incidental rather than causal?
05What imaging documentation supports M41.46 for surgical precertification?
06Is there a 7th-character extension required for M41.46?
07Can M41.46 and M41.44 (neuromuscular scoliosis, thoracic) be coded together for a long curve spanning both regions?
Sources & references
Editorial content was developed using the following public sources. Last verified May 8, 2026.
- 01CDC ICD-10-CM Tabular List 2026 (effective October 1, 2025)
- 02icd10data.comhttps://www.icd10data.com/ICD10CM/Codes/M00-M99/M40-M43/M41-/M41.46
- 03aapc.comhttps://www.aapc.com/codes/icd-10-codes/M41.46
- 04clear-institute.orghttps://clear-institute.org/blog/icd-10-coding-for-scoliosis/
- 05icdcodes.aihttps://icdcodes.ai/diagnosis/scoliosis-lumbar/documentation
- 06cms.govhttps://www.cms.gov/files/document/fy-2025-icd-10-cm-coding-guidelines.pdf
Mira AI Scribe
Mira AI Scribe captures the named neuromuscular diagnosis, the documented Cobb angle and apex vertebral level from standing radiographs, pelvic obliquity notation, and the explicit lumbar region designation. This prevents the two most common audit flags for M41.46: missing the required secondary code for the underlying condition and defaulting to the unspecified-site parent code M41.40 when a billable regional code is available.
See how Mira captures M41.46 documentation