Background: Chronic neck pain is a common problem with a poorly understood pathophysiology. Often no
underlying structural pathology can be found and radiological imaging findings are more related to age than
to a patient’s symptoms. Besides its common occurrence, chronic idiopathic neck pain is also very disabling
with almost 50% of all neck pain patients showing moderate disability at long-term follow-up. Central
sensitization (CS) is defined as “an amplification of neural signaling within the central nervous system that elicits
pain hypersensitivity,” “increased responsiveness of nociceptive neurons in the central nervous system to their
normal or subthreshold afferent input,” or “an augmentation of responsiveness of central neurons to input
from unimodal and polymodal receptors.” There is increasing evidence for involvement of CS in many chronic
pain conditions. Within the area of chronic idiopathic neck pain, there is consistent evidence for the presence
and clinical importance of CS in patients with traumatic neck pain, or whiplash-associated disorders. However,
the majority of chronic idiopathic neck pain patients are unrelated to a traumatic injury, and hence are termed
chronic idiopathic non-traumatic neck pain. When comparing whiplash with idiopathic non-traumatic neck
pain, indications for different underlying mechanisms are found.
Objective: The goal of this article was to review the existing scientific literature on the role of CS in
patients with chronic idiopathic non-traumatic neck pain.
Study Design: Systematic review.
Setting: All selected studies were case control studies.
Methods: A systematic search of existing, relevant literature was performed via the electronic
databases Medline, Embase, Web of Science, Cinahl, PubMed, and Google Scholar. All titles and
abstracts were checked to identify relevant articles. An article was considered eligible if it met
following inclusion criteria: (1) participants had to be human adults (> 18 years) diagnosed with
idiopathic non-traumatic chronic (present for at least 3 months) neck pain; (2) papers had to report
outcomes related to CS; and (3) articles had to be full-text reports or original research (no abstracts,
case-reports, reviews, meta-analysis, letters, or editorials).
Results: Six articles were found eligible after screening the title, abstract and – when necessary –
the full text for in- and exclusion criteria. All selected studies were case-control studies. Overall, results
regarding the presence of CS were divergent. While the majority of patients with chronic traumatic neck
pain (i.e. whiplash) are characterized by CS, this is not the case for patients with chronic idiopathic neck
pain. The available evidence suggests that CS is not a major feature of chronic idiopathic neck pain.
Individual cases might have CS pain, but further work should reveal how they can be characterized.
Limitations: Very few studies available.
Conclusions: Literature about CS in patients with chronic idiopathic non-traumatic neck pain is rare and
results from the available studies provide an inconclusive message. CS is not a characteristic feature of
chronic idiopathic and non-traumatic neck pain, but can be present in some individuals of the population.
In the future a subgroup with CS might be defined, but based on current knowledge it is not possible to
characterize this subgroup. Such information is important in order to provide targeted treatment.
Key words: Central sensitization, hypersensitivity, chronic pain, neck pain, idiopathic, nontraumatic, pressure pain thresholds, review
NGF, Brain and Behavioral Plasticity
