Listhesias x-rays

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spondylolisthesis x-ray radiograph

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Here is a comprehensive overview of listhesis (spondylolisthesis) on X-ray.

Listhesis — Radiographic Overview

Listhesis refers to the displacement of one vertebra relative to an adjacent one:

Anterolisthesis (spondylolisthesis) — forward displacement of the superior vertebra
Retrolisthesis — backward displacement of the superior vertebra

X-Ray Views Used

View	What It Shows
Lateral	Best view — directly shows the step-off/displacement
AP (anteroposterior)	Coronal alignment; less sensitive for slip
Oblique	Shows pars interarticularis defect ("Scotty dog" sign) — 15% of lysis lesions visible here that the lateral misses

Plain lateral radiographs demonstrate 80% of spondylolysis lesions; oblique views add another ~15%. — Miller's Review of Orthopaedics 9e

What to Look For on Lateral X-Ray

Step-off — anterior displacement of the vertebral body relative to the one below
Disc space narrowing — especially at the affected level
Facet joint degeneration — joint space loss, sclerosis (degenerative type)
Spinous process malalignment — in degenerative spondylolisthesis, the spinous process moves anteriorly with the slipped vertebra (distinguishes it from isthmic type)
Pars defect — lucency at the pars interarticularis (isthmic type)

Meyerding Grading System

The superior endplate of the lower vertebra is divided into four equal quarters:

Grade	Slip Amount
I	0–25%
II	25–50%
III	50–75%
IV	>75%
V (spondyloptosis)	>100%

Meyerding grading on lateral lumbar X-ray — the posterior edge of the upper vertebra is shown aligned at the Grade I/II boundary

Meyerding classification applied on lateral lumbar X-ray. The superior endplate of the lower vertebra is divided into quarters (I–IV); the arrow marks the posterior corner of the upper vertebra, indicating the grade of slip.

Two-View Example: Degenerative L4–L5 Spondylolisthesis

AP and lateral lumbar X-ray showing Grade I–II spondylolisthesis at L4-L5 with severe disc space narrowing

(A) AP view — coronal alignment; (B) Lateral view — yellow arrow shows anterior slip of L4 on L5 (Grade I–II); blue arrows indicate severe disc space narrowing at L4–L5.*

Types of Spondylolisthesis (Newman–Wiltse–McNab Classification)

Type	Cause	Key X-ray Feature
I — Dysplastic/Congenital	Abnormal articular processes	Slip at L5–S1, no pars defect
II — Isthmic	Pars interarticularis defect	Oblique view: "Scotty dog" collar sign
III — Degenerative	Facet joint OA	Intact neural arch; anterior spinous process shift
IV — Traumatic	Neural arch fracture	Fracture line on plain film
V — Pathologic	Bone disorder (Paget's, tumor)	Generalized bone disease features
VI — Iatrogenic	Post-laminectomy	Surgical history

Degenerative Type — Key Radiographic Points

Most common cause of lumbar spondylolisthesis over age 50
Most common level: L4–L5 (4× more common if L5 is sacralized)
Women 4× more affected than men
Lateral X-ray: anterolisthesis + facet joint narrowing/sclerosis + disc space narrowing
The neural arch is intact — even a small slip can cause canal stenosis/cauda equina syndrome
CT/MRI adds assessment of facet joint OA, foraminal narrowing, and ligamentum flavum hypertrophy

— Grainger & Allison's Diagnostic Radiology; Miller's Review of Orthopaedics 9e

Additional Measurements on Lateral X-Ray

Beyond the Meyerding grade, the lateral film also allows assessment of:

Slip angle (normally <0°, indicating lordosis at L5–S1)
Sacral inclination (normally >30°)
Pelvic incidence (normally ~50°) — used in surgical planning

Lateral lumbar X-ray showing sagittal translation and slip angle measurements

Sagittal Translation (ST) and Sagittal Angulation (SA/slip angle α) measured on lateral lumbar X-ray.

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