Critical Questions for Radiologist Regarding Maigne Protocol X-Ray Evaluation
You should ask the radiologist to specifically measure and report the coccygeal angle change between standing and sitting positions, as this is the cornerstone of identifying luxation (>25% displacement) and hypermobility (>25° flexion) according to the Maigne protocol. 1
The Four Most Critical Questions:
1. What is the degree of coccygeal flexion between standing and sitting positions?
- Request specific measurement in degrees
- Hypermobility is defined as flexion exceeding 25 degrees when comparing standing to sitting films 1
- Some sources consider >35° as significant hypermobility 2
- This measurement is essential for distinguishing normal mobility from pathologic hypermobility
2. What is the percentage of posterior displacement/subluxation of the coccyx when sitting?
- Request specific measurement as a percentage
- Luxation is defined as displacement exceeding 25% of the coccyx length 1
- More than 35% posterior subluxation is considered significant 2
- This distinguishes luxation from hypermobility, which have different clinical presentations and treatment responses
3. What is the base angle of the coccyx in the standing position?
- This angle predicts the direction in which the coccyx moves when sitting 1
- The base angle helps determine whether the coccyx will flex anteriorly or posteriorly under load
- This measurement provides context for interpreting the dynamic changes
4. Are there any morphologic abnormalities visible, specifically Type II coccyx morphology, intercoccygeal joint subluxation, or bony spicules?
- Type II coccyx morphology is associated with coccydynia 2
- Presence of bony spicules correlates with better response to surgical intervention 3
- Intercoccygeal joint subluxation is a key morphometric feature linked to pain 2
- These structural findings complement the dynamic measurements and influence treatment decisions
Why These Questions Matter:
The distinction between luxation and hypermobility has significant clinical implications. Patients with luxation typically present with a history of initial trauma, shorter symptom duration, acute pain when transitioning from sitting to standing, higher body mass index, and better response to intradiscal steroid injection 1. The hypermobility group shows intermediate characteristics between luxation and normal mobility 1.
Dynamic radiography in standing and seated positions remains the gold standard for evaluating coccydynia, with superior accuracy compared to MRI or bone scans for detecting abnormal coccygeal mobility 4. Without these specific measurements, the radiologist has essentially performed a standard static X-ray rather than the Maigne protocol evaluation you requested 1, 2.