Diagnosis and classification of chronic low back pain disorders: Maladaptive movement and motor control impairments as underlying mechanism

Low back pain (LBP) is a very common but largely self-limiting condition. The problem arises however, when LBP disorders do not resolve beyond normal expected tissue healing time and become chronic. Eighty five percent of chronic low back pain (CLBP) disorders have no known diagnosis leading to a classification of ‘non-specific CLBP’ that leaves a diagnostic and management vacuum. Even when a specific radiological diagnosis is reached the underlying pain mechanism cannot always be assumed. It is now widely accepted that CLBP disorders are multi-factorial in nature. However the presence and dominance of the patho-anatomical, physical, neuro-physiological, psychological and social factors that can influence the disorder is different for each individual. Classification of CLBP pain disorders into sub-groups, based on the mechanism underlying the disorder, is considered critical to ensure appropriate management. It is proposed that three broad sub-groups of CLBP disorders exist. The first group of disorders present where underlying pathological processes drive the pain, and the patients’ motor responses in the disorder are adaptive. A second group of disorders present where psychological and/or social factors represent the primary mechanism underlying the disorder that centrally drives pain, and where the patient's coping and motor control strategies are mal-adaptive in nature. Finally it is proposed that there is a large group of CLBP disorders where patients present with either movement impairments (characterized by pain avoidance behaviour) or control impairments (characterized by pain provocation behaviour). These pain disorders are predominantly mechanically induced and patients typically present with mal-adaptive primary physical and secondary cognitive compensations for their disorders that become a mechanism for ongoing pain. These subjects present either with an excess or deficit in spinal stability, which underlies their pain disorder. For this group, physiotherapy interventions that are specifically directed and classification based, have the potential to impact on both the physical and cognitive drivers of pain leading to resolution of the disorder. Two case studies highlight the different mechanisms involved in patients with movement and control impairment disorder outlining distinct treatment approaches involved for management. Although growing evidence exists to support this approach, further research is required to fully validate it.