Anterior vertebral slippage at the lumbosacral junction, specifically the L5-S1 level, classified as an acquired or degenerative condition rather than a traumatic fracture or congenital defect.
Verified May 8, 2026 · 6 sources ↓
- Status
- Billable
- Chapter
- 13
- Related CPT
- 10
- Region
- Spine
Documentation tips
What should appear in the chart to support M43.17.
Source · Editorial brief grounded in 6 cited references ↓
- Specify the vertebral level explicitly — 'L5-S1 spondylolisthesis' — not just 'lumbosacral' or 'lower back slip', to support M43.17 over M43.16 or M43.10.
- Record the Meyerding grade (I–IV) or percentage of anterior translation on standing lateral radiograph; this supports medical necessity for surgical referral or fusion.
- Note whether the spondylolisthesis is isthmic (pars defect), degenerative, or dysplastic, as etiology affects surgical planning and payer authorization even though the ICD-10 code is the same.
- Document whether flexion-extension films show dynamic instability, which differentiates stable from unstable slippage and drives step-therapy requirements for many payers.
- If the patient has a prior fusion at L5-S1, note that separately; adjacent-level disease changes the surgical CPT code selection and may require an additional diagnosis code.
- Confirm the condition is not acute traumatic or congenital before assigning M43.17 — Excludes1 conditions are coding errors, not just documentation gaps.
Related CPT procedures
Procedure codes commonly billed with M43.17. 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 M43.17 and adjacent codes.
Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓
- Assigning M43.17 when the imaging report says 'lumbar spondylolisthesis at L4-L5' — that is M43.16, not M43.17; the lumbosacral code is L5-S1 only.
- Using M43.17 for acute traumatic lumbosacral slippage — that is an Excludes1 violation; code to S33.1xx with the appropriate 7th character (A, D, or S) instead.
- Defaulting to M43.10 (site unspecified) when the physician note references 'lumbosacral' but query would confirm L5-S1 — specificity is billable and should not be abandoned without querying.
- Confusing spondylolisthesis (M43.17) with spondylolysis (M43.07); spondylolysis is a pars defect without forward slip — if both are documented, both codes may be reported.
- Omitting M43.17 entirely when a spinal fusion is coded, assuming the diagnosis is captured in the procedure — payers require the ICD-10 diagnosis code on the claim regardless of procedure specificity.
Clinical context
Source · Editorial summary grounded in 6 cited references ↓
M43.17 applies exclusively to spondylolisthesis at the lumbosacral region — the L5-S1 junction. If the slip is documented at L4-L5, use M43.16 (lumbar region). If the note reads 'lumbar spondylolisthesis' without specifying the level, query the provider before defaulting to unspecified M43.10; L5-S1 is the most common site but specificity must come from the provider, not the coder.
Three Excludes1 conditions must be ruled out before using M43.17. Acute traumatic spondylolisthesis of the lumbosacral region codes to S33.1 (fracture category). Acute traumatic slippage at other spinal sites codes to the appropriate fracture code for that region. Congenital spondylolisthesis codes to Q76.2. M43.17 is reserved for acquired, degenerative, or isthmic (lytic) presentations that are not acute traumatic and not congenital.
Common clinical scenarios that generate M43.17 include isthmic spondylolisthesis from a pars interarticularis defect at L5, degenerative spondylolisthesis at L5-S1, and pre- or post-operative documentation of L5-S1 slippage in fusion workups. The Meyerding grade (I through IV) and percentage slip documented on standing lateral radiographs or flexion-extension films support medical necessity for conservative care, injections, or surgical intervention.
Sibling codes
Other billable codes under M43.1 (laterality / anatomic variants).
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 6 cited references ↓
01What is the difference between M43.16 and M43.17?
02Can M43.17 be used for isthmic (pars defect) spondylolisthesis at L5-S1?
03What code replaces M43.17 for an acute traumatic lumbosacral slippage?
04Is M43.17 appropriate when both L4-L5 and L5-S1 slippage are documented?
05Which CPT codes for lumbar fusion commonly pair with M43.17?
06Does M43.17 require a 7th character?
07Should congenital spondylolisthesis at L5-S1 be coded to M43.17?
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/M43-/M43.17
- 03aapc.comhttps://www.aapc.com/codes/icd-10-codes/M43.17
- 04icdcodes.aihttps://icdcodes.ai/diagnosis/lumbar-spondylolisthesis/documentation
- 05aapc.comhttps://www.aapc.com/blog/42504-medical-diagnosis-spondylolisthesis/
- 06outsourcestrategies.comhttps://www.outsourcestrategies.com/blog/how-to-document-spondylolisthesis-with-accurate-icd-10-codes/
Mira AI Scribe
Mira captures the vertebral level (L5-S1), Meyerding grade or slip percentage from standing lateral imaging, presence or absence of pars defect, and any instability noted on flexion-extension films. That documentation locks in M43.17 over the unspecified M43.10, prevents Excludes1 conflicts with traumatic or congenital codes, and satisfies payer medical necessity criteria for fusion or injection procedures.
See how Mira captures M43.17 documentation