Chronic Post-Traumatic Neck Pain

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Whiplash is a compressive injury. It is not a flexion/extension or acceleration/deceleration injury. Following impact, the trunk is thrust upwards, against the inertia of the head. This causes compression into a sigmoid deformation of the cervical spine at about 110ms after impact. During the deformation, the lower cervical segments undergo abnormal rotation into extension. The anterior annulus fibrosis is strained, and the facet joints are impacted. Extension is completed as the base of the neck descends.

Anatomy

Main article: Cervical Spine Anatomy

The cervical disc are very different to lumbar discs. The annulus is non-concentric, and only well-developed in the anterior aspect of the disc. It is more of an interosseous ligament which is non-load bearing.

Epidemiology

Studies have consistently shown that the facet joints are implicated 50-60% of the time in chronic post-traumatic neck pain when identified via concordant comparative medial branch blocks.

The cervical disc is implicated 16% of the time when evaluated by provocative discography.

Pathophysiology

Specific tissue damage seen are tears of the anterior anulus fibrosis, strain or tears of the facet joint capsules (rim lesions and avulsions), and impaction injuries of the facet joints. Impaction injuries include contusions of the intra-articular meniscoids with intra articular haemorrhage, and subchondral and transarticular fractures.

History

Assess for red flags.

Examination

There is no proven diagnostic value in the physical examination. There is good reliability of tenderness over the facet joints, but it lacks validity. Testing for gross range of motion has not been tested for reliability and lacks validity. Provocation of neck pain with various movements may be seen but this is also not diagnostic of a specific pain source.

Imaging

Imaging will often be normal or show "cervical spondylosis." This does not exclude a nociceptive source of pain. Osteoarthritis of the facet joints may be seen. Cervical degenerative disease refers to the combination of cervical spondylosis and facet joint osteoarthritis.

In general there is no link between cervical degenerative joint disease and pain. However, there is a slight clinical significance with degenerative disc (but not facet osteoarthritis) findings at the C5/6 level. There is also an association with marked (level 3) degenerative changes and neck pain.

CT scintigraphy is used a lot in New Zealand. It is good for picking up small occult fracture and tumours etc. It does not however show pain, only increased blood flow. It tends to miss cases where there is pain arising from soft tissue damage for example capsular tears.

Medial Branch Blocks

Main article: Cervical Facet Joint Precision Treatment

Provocative Discography

There is a very high false positive rate with disc stimulation. Discography should never been done unless medial branch blocks have been done and are negative.

The diagnosis of cervical discogenic pain can be made when all the following criteria are met:

1. Cervical facet joint pain has been excluded with medial branch blocks
2. Disc stimulation has been performed with correct technique
3. Disc stimulation reproduces concordant pain
4. Disc stimulation reproduces pain of at least 7/10 in intensity
5. Disc stimulation of adjacent discs does not reproduce pain.

Prognosis

There is good recovery after the first year, but then it tails off. At 24 months 14% have not fully recovered, and 4% are severely affected.

Important Artciles

• {{#l:Bogduk2011 - On Cervical Zygapophysial Joint Pain After Whiplash.pdf}}

References

• Kaneoka, K., Ono, K., Inami, S., Ochiai, N., & Hayashi, K. (2002). The Human Cervical Spine Motion During Rear-Impact Collisions. Journal of Whiplash & Related Disorders, 1(1), 85–97. doi:10.3109/j180v01n01_08
• Kaneoka et al.. Motion analysis of cervical vertebrae during whiplash loading. Spine 1999. 24:763-9; discussion 770. PMID: 10222526. DOI.