Thoracolumbar spine trauma

ACR AC Acute Spinal Trauma (2024); ACR AC Suspected Spine Trauma-Child

The bony question, and the one place in the lumbar spine where CT is the right first study rather than a substitute for MRI. Adults with a significant mechanism or clinical findings go straight to thin-section CT with reformats; children go to radiographs first, because their injury pattern and their dose stakes are both different; and MRI enters afterwards for the cord, the disc and the posterior ligamentous complex, which decide stability and which CT cannot see.

Blunt trauma with thoracolumbar midline tenderness, a high-energy mechanism, a distracting injury, an unassessable patient, or a neurological deficit — or a low-energy mechanism in a patient with osteoporosis or an ankylosing spinal condition, where the threshold to image is far lower.

Referenced decision support — confirm against your local protocol.

Decision support, not a directive. Protocols and timings shown are typical published ones — your local protocol takes precedence, and the vetting radiologist decides.

The request in front of you

Everything is optional. Leave a field alone and the answer assumes nothing — the verdict updates as you go.

Study requested

What the referrer actually asked for. It is evidence of intent, not a constraint on the right answer.

Contrast as written

What the request form says, not what it should say.

Age

Pick a band, or type an exact age if it matters.

years

Pregnancy status

Haemodynamic state

The fact that lets a pathway waive its own requirements. A crashing patient does not wait for a score.

GCS

Red flags

These accumulate rather than exclude. Back pain with one of these is a different question from back pain.

Renal risk factors

The question a vetter can actually answer from the request. An explicit “none known” is a real answer, and it removes checks rather than deferring them.

Previous contrast reaction

The pathway — tap anything already done

Marking a study complete moves the answer on. A patient arrives partway through a pathway far more often than at the start of one.

Accept as requested

CT Lumbar Spine — Unenhanced, Thin Section

CT Lumbar Spine

What we'd amend, and why

This is the indication in which CT of the lumbar spine is the reference study rather than a compromise, and it is worth being explicit about why, because two other cards in this file redirect a lumbar CT request away. There the question is neural — cauda equina compression, a disc fragment against the thecal sac — and CT cannot resolve soft tissue against cerebrospinal fluid well enough to fail safely. Here the question is bony, and bone is what CT is best at in all of radiology. Radiographs miss a clinically significant proportion of thoracolumbar fractures, particularly posterior element and endplate injuries and particularly at the thoracolumbar junction where bowel gas, the diaphragm and endplate obliquity defeat plain films — and it is exactly those injuries that determine whether the fracture is stable. Thin-section acquisition with sagittal and coronal reformats resolves them reliably, defines vertebral body height loss, canal retropulsion and interpedicular widening, and feeds directly into the classification the surgeon uses. Check first for an existing trauma or staging acquisition: reformats from a dataset already on the system answer the question without a second exposure.

Nothing needs resolving before this goes ahead. Routine checks below are owned downstream.

How was this decided?

pathwayadult — Adults
rulerule-paeds-dose — Child-sized technique and contrast dose; checked by Radiographer at the scanner
rulerule-pregnancy-ionising — Pregnancy status before an ionising exposure; checked by Radiographer at the scanner

Decision support only. Local protocol takes precedence.

Handled at the scanner(2)nothing for you to do

Settled and owned downstream. Each returns to a radiologist only on the stated trigger.

Child-sized technique and contrast dose
Confirm that a size- or weight-based protocol is selected — child-sized kV and mAs against size-based diagnostic reference ranges — and that contrast volume is calculated by weight rather than taken from an adult default. Weight-based iodinated contrast volumes of roughly 1.5–2.0 mL/kg are widely used in paediatric CT.
Radiographer at the scannerAt the scanner
Flags back if: No paediatric or size-based protocol exists on the scanner for the requested examination, or the requested coverage or number of phases exceeds what the clinical question needs — for example a multiphase study where a single phase answers it, or whole-body coverage for a focal question.
Pregnancy status before an ionising exposure
Make the pregnancy enquiry immediately before the exposure and record the answer. In the UK this is a statutory operator duty discharged at the time of exposure under the employer’s written procedures required by IR(ME)R 2017 — it is not something the vetting radiologist can perform or pre-empt, and a request is complete without it.
Radiographer at the scannerAt the scanner
Flags back if: The patient states that she is, or may be, pregnant AND the uterus is in or near the primary beam. The exposure is then paused for re-justification by the IR(ME)R practitioner before it proceeds.

Worth asking the referrer (3)

None of these hold the request up. They sharpen the protocol or the plan that follows.

Is there any motor, sensory or sphincter deficit, and is it progressing?
A deficit adds MRI to the plan rather than replacing the CT, and it changes the timescale from routine trauma workup to same-day. It is also what makes the difference between a fracture that is characterised electively and one whose cord consequences have to be defined before an operating list is booked.
Is there known ankylosing spondylitis or diffuse idiopathic skeletal hyperostosis?
It lowers the threshold to image to almost nothing, and it widens the coverage: a trivial mechanism can produce an unstable transverse fracture through fused bone, and non-contiguous injuries mean the whole spine rather than the painful segment is at risk.
Has a trauma or body CT already been performed in this episode?
If it has, dedicated thin reformats through the spine usually answer the question with no further exposure. A second acquisition over the same anatomy is dose without information.

Pathways

Big forks are separate pathways; the first whose conditions match is the one used.

Unassessable, unstable or a high-energy mechanism — CT first at any age

Role	Study & protocol	Why this answers the question
First line	CT Lumbar Spine CT Lumbar Spine — Unenhanced, Thin Section usually appropriate	The paediatric preference for radiographs rests on an examinable child with a low-energy mechanism, and none of the three states here is that: a high-energy mechanism, a Glasgow Coma Scale of 12 or less and haemodynamic instability are the situations the ACR itself excepts, in which CT is the first study rather than the second, in the child as much as in the adult. A radiograph in a patient who cannot be examined clears nothing, and the second acquisition it leads to costs more dose than starting correctly. Check first for an existing trauma or body CT: thin reformats from a dataset already on the system answer the spinal question with no further exposure, and in an unstable patient they are usually the only acquisition that should be happening at all. Resuscitation precedes imaging; the spine is not the reason this patient is unstable.
First line	CT Thoracic Spine CT Thoracic Spine — Unenhanced, Thin Section	Co-equal with the lumbar block for the same reason it is co-equal on the adult arm: the injuries cluster at the thoracolumbar junction, which sits in the overlap of the two, and a request written either way is asking the same question. In a high-energy mechanism review the whole thoracolumbar spine rather than stopping at the first fracture — non-contiguous injuries at a second level are common and are exactly what gets missed once attention has landed somewhere.
Second line	MRI Whole Spine MRI Whole Spine — suspected metastatic cord compression	After the CT and once the patient is stable enough to be in a magnet: the cord and conus, the disc, an epidural haematoma and the posterior ligamentous complex whose integrity moves an injury across the operative threshold. In a child with a deficit and normal bony imaging it is the study that finds the injury, because the immature spine transmits force to the cord without fracturing. It is slow and hard to deliver safely in a ventilated or unstable patient, which is why it follows rather than replaces the CT.

This arm is the escape hatch for the paediatric ladder below it, not a licence to scan children with minor injuries. It fires only on a stated high-energy mechanism, a depressed conscious level or haemodynamic instability.

Children

Role	Study & protocol	Why this answers the question
First line	Spinal radiograph Spinal radiograph — AP and lateral usually appropriate	The trade-off runs the other way in children. Thoracolumbar CT irradiates active haematopoietic marrow along the whole length of the trunk, and in a girl it irradiates breast tissue and ovaries, at an age where the lifetime attributable risk per unit dose is at its highest. Against that, the paediatric injury pattern is dominated by the compression fracture and by ligamentous and physeal injury, and the compression fracture is the injury radiographs are best at. The ACR accordingly makes radiography the preferred initial study in this group, with CT reserved for the abnormal, inadequate or clinically discordant film — and for the child with a high-energy mechanism, a deficit or an unassessable conscious level, in whom CT is the first study rather than the second.
Second line	CT Lumbar Spine CT Lumbar Spine — Unenhanced, Thin Section	Indicated where the radiographs are abnormal, technically inadequate or discordant with a significant clinical concern, and as the first study in a child with a high-energy mechanism, a neurological deficit or an unassessable conscious level. Where a trauma body CT has already been performed, reformats from it serve this purpose and no separate acquisition should be added.
Problem solving	MRI Whole Spine MRI Whole Spine — suspected metastatic cord compression	The study for the child with a neurological deficit and normal bony imaging — a recognised and characteristically paediatric pattern in which the elastic immature spine transmits injury to the cord without fracturing. It is also what assesses the posterior ligamentous complex and the physes when instability is suspected despite an unremarkable CT.

A child who can be examined, is alert, has no midline tenderness, no distracting injury and no deficit may need no imaging at all, and that remains the highest-value output of this pathway.

Adults

Matches your inputsDefault

Role	Study & protocol	Why this answers the question
First line	CT Lumbar Spine CT Lumbar Spine — Unenhanced, Thin Section usually appropriate	This is the indication in which CT of the lumbar spine is the reference study rather than a compromise, and it is worth being explicit about why, because two other cards in this file redirect a lumbar CT request away. There the question is neural — cauda equina compression, a disc fragment against the thecal sac — and CT cannot resolve soft tissue against cerebrospinal fluid well enough to fail safely. Here the question is bony, and bone is what CT is best at in all of radiology. Radiographs miss a clinically significant proportion of thoracolumbar fractures, particularly posterior element and endplate injuries and particularly at the thoracolumbar junction where bowel gas, the diaphragm and endplate obliquity defeat plain films — and it is exactly those injuries that determine whether the fracture is stable. Thin-section acquisition with sagittal and coronal reformats resolves them reliably, defines vertebral body height loss, canal retropulsion and interpedicular widening, and feeds directly into the classification the surgeon uses. Check first for an existing trauma or staging acquisition: reformats from a dataset already on the system answer the question without a second exposure.
First line	CT Thoracic Spine CT Thoracic Spine — Unenhanced, Thin Section usually appropriate	Deliberately co-equal with the lumbar acquisition rather than ranked below it, because in practice this is one request and one reconstruction task: the injuries cluster at the thoracolumbar junction, which sits in the overlap of the two blocks, and a request written as either "CT thoracic spine" or "CT lumbar spine" for a thoracolumbar mechanism is asking the same clinical question. Ranking them would produce a sequencing correction where none is warranted. What does matter is coverage: the study must run from a countable landmark above the suspected level to below it, and where the mechanism is high-energy or a fracture is found, the whole thoracolumbar spine should be reviewed, because non-contiguous injuries at a second level are common and are missed when attention stops at the first fracture.
Second line	MRI Whole Spine MRI Whole Spine — suspected metastatic cord compression	What CT cannot see is what MRI is added for, and the list is short and decisive: the spinal cord and conus, the disc, an epidural haematoma, and the posterior ligamentous complex. The ligamentous assessment is the one that changes operative decisions, because most thoracolumbar classification schemes weight posterior ligamentous integrity heavily and CT infers it from bony surrogates — interspinous widening, facet diastasis — rather than seeing it. MRI is also what dates a vertebral collapse and what identifies an underlying pathological lesion when the mechanism does not fit the injury, which in an older patient is frequently the real question. It follows the CT rather than replacing it: MRI is slow, hard to deliver safely in an unstable or ventilated patient, and poor at cortical bone, so a request for MRI before any CT in acute trauma is out of sequence rather than out of place.

Radiographs are off the adult ladder for the same reason they are off the cervical one: they miss the posterior element and endplate injuries that decide stability, and at the thoracolumbar junction they are frequently uninterpretable. A normal thoracolumbar radiograph does not clear the spine.
A neurological deficit does not change the first study — it adds MRI to the plan and compresses the timescale. Neither the deficit nor known ankylosing spinal disease can be read from the request, so both are asked explicitly on this card.
In known ankylosing spondylitis or diffuse idiopathic skeletal hyperostosis, image the whole spine rather than the painful segment, and treat a trivial mechanism as sufficient. The fracture is often a subtle transverse lucency through fused bone and is highly unstable.
This card is about the bony injury. A patient with saddle anaesthesia, bilateral radicular symptoms or new sphincter dysfunction is asking the cauda equina question, where CT cannot fail safely and MRI is the study.

Pitfalls

Rescanning anatomy already covered by a trauma or staging acquisition. The reformats are the study; a second pass is dose without information.
Treating a normal CT as excluding injury. It does not exclude cord injury, disc herniation, epidural haematoma or posterior ligamentous complex disruption, and the ligamentous injury is the one that decides whether the fracture is operative.
Stopping at the first fracture. Non-contiguous injuries at a second level are common, and the second level is the one that gets missed.
Missing a fracture through an ankylosed segment, where the abnormality is a subtle transverse lucency in fused bone that looks trivial and is highly unstable — and where the mechanism is often described as minor.
Miscounting levels, particularly with transitional lumbosacral anatomy. State the convention used; the surgeon operates on the level named in the report.
Poor sagittal reformat quality from a thick primary acquisition, which hides exactly the endplate and posterior element fractures the study was done to find.
Assuming a vertebral collapse in an older patient is osteoporotic. Marrow replacement, a soft-tissue component or posterior element involvement point elsewhere, and CT dates a fracture poorly — the fluid-sensitive MRI sequence is what says whether it is acute.
Defaulting a child to CT because that is what the adult pathway does, which irradiates trunk marrow, breast and gonads for a small gain in sensitivity for an injury pattern radiographs handle well.
Requesting MRI before any CT in acute trauma. It is out of sequence rather than out of place: MRI is slow, difficult to deliver safely in an unstable or ventilated patient and poor at cortical bone, so the CT comes first and usually answers the bony question on its own.
Reading this card across to the cauda equina or non-traumatic back pain questions. There the question is neural, CT cannot exclude the diagnosis, and a lumbar CT request is redirected rather than protocolled.

Priors — what to pull first

Prior imaging is what separates an old healed collapse from an acute injury, and in the elderly and in ankylosing conditions that distinction is the whole report.
A trauma or staging CT performed earlier in the same episode very often already contains the spine; review it for reformats before adding an acquisition.
Documented baseline alignment matters for judging subtle translation, particularly in a spine that is already deformed.

What makes a good request

Most thoracolumbar injuries cluster at the thoracolumbar junction, between roughly T11 and L2, where the stiff rib-splinted thoracic segment meets the mobile lumbar spine. That is also the region worst served by radiographs, because of overlying bowel gas, the diaphragm and the obliquity of the endplates.
The ACR makes CT the primary modality for suspected thoracolumbar trauma in adults, and radiography the preferred initial study in children. The adult recommendation rests on the poor sensitivity of radiographs for posterior element and endplate fractures, which are precisely the injuries that determine stability.
Where a trauma or staging body CT has already been acquired, dedicated thin reformats from that dataset usually answer the spinal question with no further exposure. Rescanning a region already covered is one of the more common avoidable exposures in a trauma department, and the reformats — not a second acquisition — are the study.
CT establishes the fracture; MRI establishes what it means. The posterior ligamentous complex is the component of most classification schemes that CT infers rather than sees, and in an injury sitting near the operative threshold the ligamentous assessment is what moves it across.
Non-contiguous injuries at a second spinal level are common enough that finding one fracture is a reason to look harder at the rest of the spine, not a reason to stop.
Ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis change everything: a trivial mechanism produces a highly unstable transverse fracture through fused bone, the abnormality can be a subtle lucency that looks trivial, radiographs are unreliable, and the whole spine rather than the painful segment is at risk.
In an older patient the question is often not whether there is a collapse but whether it is acute, and CT answers that poorly. Marrow oedema on a fluid-sensitive MRI sequence is what dates a vertebral fracture, and it is also what identifies the underlying pathological lesion when the mechanism does not fit the injury.

Scoring this once it is done

The classification and risk tools this question ends in.

TLICS — Thoracolumbar Injury Classification & Severity Score AO Spine Thoracolumbar Injury Classification Denis Three-Column Classification ASIA Impairment Scale (AIS) with Frankel Mapping SLICS — Subaxial Injury Classification & Severity Score NEXUS Cervical Spine Criteria Ottawa Ankle / Knee / Foot Rules Garden Classification (Femoral Neck Fractures)Salter-Harris Classification (Physeal Fractures)

How these studies are acquired

Contrast, phases and timing for every study on the pathways above.

CT Lumbar Spine — Unenhanced, Thin Section CT Thoracic Spine — Unenhanced, Thin Section MRI Whole Spine — suspected metastatic cord compression Spinal radiograph — AP and lateral

Confirm locally

CT Lumbar Spine — Unenhanced, Thin Section: timings are typical — confirm against local protocol.
Timings, contrast volumes and rates above are typical published values. Your department's protocol, scanner and patient population decide the actual numbers.
Safety thresholds and premedication policy follow local policy where it differs from the cited guidance.

References

Implemented from the cited published sources. Educational and workflow support only; confirm against current guidelines and local policy before clinical use.