In a patient with torticollis whose cervical spine X‑ray shows pseudo‑subluxation of C2, C3 and C4, what does this finding indicate and how should the torticollis be managed?

Pseudosubluxation of C2-C4 in Torticollis: Interpretation and Management

Pseudosubluxation of C2, C3, and C4 on cervical spine X-ray in a patient with torticollis is most likely a normal physiological variant in children under 8 years of age, but requires careful clinical correlation and potentially advanced imaging to definitively exclude true ligamentous injury, particularly if there is a history of trauma.

Understanding Pseudosubluxation

What This Finding Represents

• Pseudosubluxation of C2 on C3 is a well-recognized normal anatomical variant occurring in approximately 40% of children under 8 years of age 1.
• This physiological finding represents normal ligamentous laxity in the developing pediatric cervical spine, not pathological instability 1.
• The finding can extend to multiple levels (C2-C3-C4) and is significantly more common in younger children 2.

Critical Distinction: Physiological vs. Pathological

The key to distinguishing pseudosubluxation from true injury is evaluating the spinolaminal line (Swischuk line) 1:

• Draw a line between the anterior aspects of the C1 and C3 spinous processes 1.
• In pseudosubluxation, this line should pass within 1-2 mm of the anterior cortex of the C2 spinous process 1.
• If the C2 spinous process lies >2 mm posterior to this line, true subluxation should be suspected 3.

When to Suspect True Injury

High index of suspicion is required when 3, 4:

• There is a clear history of significant trauma (trampoline accidents, motor vehicle collisions, falls from height) 3, 1.
• The patient has persistent neck pain beyond what would be expected for simple torticollis 3.
• Clinical examination reveals neurological deficits or signs of spinal cord injury 5.
• The patient is an adult (pseudosubluxation is rare after age 8 and extremely uncommon in adults) 4.

Management Algorithm

Initial Clinical Assessment

Use the PINCH assessment tool to evaluate torticollis etiology 5:

• Posture: Assess head tilt and rotation pattern
• Inspection: Look for masses, asymmetry, or skin changes
• Neurology: Evaluate for focal deficits or upper motor neuron signs
• Cervical spine: Palpate for tenderness, assess range of motion
• History: Determine onset, trauma history, associated symptoms

Imaging Decision-Making

If pseudosubluxation is identified on X-ray 6, 3, 4:

• In children <8 years without trauma history and normal neurological examination: Pseudosubluxation can be considered a benign variant requiring no additional imaging 2.
• In children with trauma history or persistent symptoms: CT cervical spine without IV contrast is indicated to evaluate for fractures or true subluxation 6, 3.
• If CT shows reversal of lordosis, anterolisthesis, or equivocal findings: MRI cervical spine without IV contrast is the definitive study to evaluate ligamentous injury 6, 4.

MRI is superior to CT and flexion-extension radiographs for identifying cervical spine ligament injuries 6:

• MRI correctly predicts 88% of lesions requiring surgical intervention 6.
• Flexion-extension radiographs are inadequate in 30-95% of cases due to limited motion and carry real danger of producing neurologic injury 6.
• Flexion-extension radiographs should NOT be performed in the acute setting 6.

Treatment Based on Etiology

For congenital muscular torticollis (CMT) without true cervical spine injury 7:

• Physical therapy is first-line treatment, with 96.1% of patients receiving PT for an average of 13.3 months 8.
• Conservative treatment leads to resolution in 51.2% and improvement in 45.5% of cases 8.
• Botulinum toxin injection may be considered for recalcitrant cases 8.
• Surgical release of the sternocleidomastoid is reserved for failure of conservative therapy with persistent fibrosis, marked shortening, or >15° restriction in rotation or lateral flexion 9.

For true C2-C3-C4 subluxation confirmed on advanced imaging 3:

• Halo traction may be required for 8-10 weeks to achieve anatomic alignment 3.
• Surgical stabilization is necessary in approximately 1% of cases with unstable cervical spine injury 6.

Critical Pitfalls to Avoid

Do not dismiss pseudosubluxation findings without proper clinical correlation 3, 4:

• A case report documented a 6-year-old with true C2-C3 and C3-C4 subluxation initially misinterpreted as pseudosubluxation, requiring halo traction 3.
• Adult patients with pseudosubluxation after trauma require MRI to definitively exclude pathological injury 4.

Do not obtain flexion-extension radiographs in the acute setting 6:

• These studies are inadequate in 28-97% of cases 6.
• They carry real danger of producing neurologic injury 6.
• They fail to reveal most ligament injuries identified on MRI 6.

Do not assume all torticollis is muscular in origin 10:

• Cervical vertebral anomalies (hemivertebrae, fusion anomalies) can present as congenital torticollis 10.
• Misdiagnosis leads to prolonged inappropriate treatment with significant financial and psychosocial burden 10.