ICD-10-CM · Spine

M43.18

Acquired forward displacement (slippage) of a vertebra in the sacral or sacrococcygeal spinal region, not congenital in origin and not due to acute trauma.

Verified May 8, 2026 · 6 sources ↓

Status: Billable
Chapter: 13
Related CPT: 15
Region: Spine

Drawn from CDCICD10DataAAPCOutsourcestrategiesNIH

Documentation tips

What should appear in the chart to support M43.18.

Source · Editorial brief grounded in 6 cited references ↓

Specify the exact spinal level in the report (e.g., S1-S2 or sacrococcygeal junction) — 'lower spine' or 'lower back' is insufficient to support M43.18 over M43.17 or M43.16.
Document the type of spondylolisthesis (degenerative, isthmic/lytic, etc.) and grade (Meyerding I–IV) to support medical necessity for surgical or advanced imaging workup.
Record whether the condition is acquired, to distinguish from congenital spondylolisthesis (Q76.2), which is explicitly excluded from M43.18.
Include imaging modality and findings (standing lateral X-ray, CT, or MRI) confirming vertebral translation at the sacral or sacrococcygeal level.
If radiculopathy or neurogenic claudication is present, code it separately — M43.18 does not capture associated nerve root compromise.

Related CPT procedures

Procedure codes commonly billed with M43.18. Linking the right diagnosis to the right procedure is what establishes medical necessity.

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

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.

72110 $53.44

Radiologic examination of the lumbar spine (lumbosacral) with a minimum of four views, including oblique and/or bending views.

72114 $61.79

Radiologic examination of the lumbosacral spine, complete series with bending (flexion/extension) views — minimum of 6 views total.

72148 $191.72

Non-contrast MRI of the lumbar spine used to evaluate disc pathology, spinal stenosis, nerve root compression, and other structural abnormalities without administration of contrast material.

72158 $318.31

MRI of the lumbar spinal canal and its contents performed first without contrast, then repeated after contrast administration for enhanced visualization.

27279 $758.53

Minimally invasive arthrodesis of the sacroiliac joint using a transfixing implant device placed percutaneously across the joint.

22533 $1,547.80

Spinal fusion of a lumbar vertebral segment performed through a lateral extracavitary approach, including minimal discectomy to prepare the interspace (not performed solely for decompression).

22558 $1,423.88

Anterior interbody arthrodesis of the lumbar spine using an anterior or anterolateral approach, including the minimal discectomy required to prepare the interspace for fusion.

22612 $1,467.64

Posterior or posterolateral lumbar arthrodesis of a single interspace, performed via a posterior approach with bone graft and typically pedicle screw fixation to achieve vertebral segment fusion.

22630 $1,510.72

Posterior interbody arthrodesis of a single lumbar interspace, including laminectomy and/or discectomy performed to prepare the interspace for fusion rather than for decompression.

22633 $1,700.11

Single-level lumbar arthrodesis combining posterior or posterolateral technique with posterior interbody technique, including laminectomy and/or discectomy sufficient to prepare the interspace — performed as one surgical session at one lumbar interspace.

72131 View procedure details

72132 View procedure details

72133 View procedure details

72149 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M43.18 and adjacent codes.

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

Assigning M43.18 when the documented level is lumbosacral (L5-S1) — that slippage belongs at M43.17, not M43.18.
Using M43.18 for acute traumatic sacral spondylolisthesis — acute trauma codes (S-series fracture codes) apply instead; M43.18 is for acquired, non-traumatic displacement.
Defaulting to M43.10 (site unspecified) when imaging clearly identifies the sacral region — specificity is available and should be captured.
Confusing spondylolysis (M43.08, defect in the pars interarticularis) with spondylolisthesis (M43.18, actual vertebral displacement) — these are distinct diagnoses with their own code families.
Failing to code concomitant radiculopathy or spinal stenosis as a secondary diagnosis, leaving clinical severity underdocumented on the claim.

Clinical context

Source · Editorial summary grounded in 6 cited references ↓

M43.18 codes spondylolisthesis specifically localized to the sacral and sacrococcygeal region. This is the most distal segment of the spine and is anatomically distinct from the lumbosacral junction (M43.17) and the lumbar region (M43.16). Use M43.18 only when imaging and clinical documentation explicitly identify the sacral or sacrococcygeal level as the site of vertebral slippage — not as a default when the lumbosacral level is ambiguous.

This code sits under parent code M43.1 (Spondylolisthesis) and carries two critical excludes: congenital spondylolisthesis maps to Q76.2, and acute traumatic spondylolisthesis of the lumbosacral region maps to S33.1. For acute trauma at sites other than lumbosacral, code to the appropriate vertebral fracture code by region. M43.18 is reserved for acquired, non-traumatic displacement at the sacral/sacrococcygeal level.

In practice, true isolated sacral-level spondylolisthesis is uncommon compared to lumbar or lumbosacral presentations. When a provider documents slippage at or near the sacrum without specifying the exact level, query for clarification before defaulting to M43.18 — the distinction between M43.17 (lumbosacral) and M43.18 (sacral/sacrococcygeal) hinges on imaging-confirmed level documentation.

Sibling codes

Other billable codes under M43.1 (laterality / anatomic variants).

M43.19

Spondylolisthesis, multiple sites in spine

M43.14

Spondylolisthesis, thoracic region

M43.12

Spondylolisthesis, cervical region

M43.17

Spondylolisthesis, lumbosacral region

M43.15

Spondylolisthesis, thoracolumbar region

M43.16

Spondylolisthesis, lumbar region

M43.10

Spondylolisthesis, site unspecified

M43.11

Spondylolisthesis, occipito-atlanto-axial region

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01What is the difference between M43.17 and M43.18?

M43.17 codes spondylolisthesis at the lumbosacral region (the L5-S1 junction), while M43.18 codes displacement at the sacral and sacrococcygeal region proper. The distinction requires imaging documentation of the specific level — do not use M43.18 when the slippage is at L5-S1.

02Can M43.18 be used for congenital sacral spondylolisthesis?

No. Congenital spondylolisthesis is excluded from M43.18 by a Type 1 Excludes note and maps to Q76.2. M43.18 applies only to acquired (non-congenital) displacement.

03Is M43.18 appropriate after acute sacral trauma?

No. Acute traumatic spondylolisthesis requires fracture or dislocation codes from the S-series (e.g., S32.1xx for sacral fracture). M43.18 is for acquired, non-traumatic vertebral slippage — not acute injury presentations.

04Should I code radiculopathy separately when using M43.18?

Yes. M43.18 does not capture nerve root involvement. If the provider documents radiculopathy or neurogenic symptoms, add the appropriate radiculopathy or myelopathy code as a secondary diagnosis to fully represent the clinical picture and support medical necessity.

05What imaging is needed to support M43.18?

Standing lateral plain films (X-ray), CT, or MRI confirming anterior vertebral translation at the sacral or sacrococcygeal level. Grade (Meyerding classification) should be documented. Flexion-extension views are useful when instability or dynamic slippage is suspected.

06What is the ICD-10-CM parent code for M43.18, and does it matter for billing?

The parent code is M43.1 (Spondylolisthesis), which is non-billable. M43.18 is the billable, most-specific child code for the sacral/sacrococcygeal region. Always bill the billable child code — submitting M43.1 alone will result in claim rejection.

07Can M43.18 and M43.08 (spondylolysis, sacral region) be coded together?

Only if both conditions are independently documented. Spondylolysis (M43.08) is a defect in the pars interarticularis without displacement; spondylolisthesis (M43.18) is actual vertebral slippage. They are distinct diagnoses — verify with the treating provider before coding both.

Sources & references

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

Mira AI Scribe

Mira captures the imaging-confirmed vertebral level (sacral or sacrococcygeal), displacement grade, condition type (degenerative vs. isthmic), and any associated nerve root symptoms from the encounter note — preventing a downcode to M43.10 (unspecified site) or a miscoded M43.17 (lumbosacral) that could trigger a payer audit or medical necessity denial.

See how Mira captures M43.18 documentation