This issue is dedicated towards the subject of back pain. One needs to understand basic biomechanical and structural principles such as; The Three Joint Complex and the Three Phases of the Degenerative Process.
The Three Joint Complex
Each spinal motion segment (vertebrae) is composed of three joints, two synovial posterior facet joints and an interveterbral disc. Injuring one component of the three-joint complex affects its function and also the other two components. The fourth component of the spinal segment is the paraspinal musculature, which originates and inserts on the vertebrae and have direct and indirect influence on the function of the spinal segment.
The three phases of the degenerative process
1. Dysfunctional Phase
The majority of patients seen in low back pain clinics suffer from dysfunction. During this phase, the pathological changes are relatively minor and perhaps reversible. The term dysfunction implies that at one anatomical level, (usually L4-L5 or L5-S1 in low back cases), that the three components of a joint are not functioning well (dysfunctional).
The two mechanisms responsible for the changes in the three-joint complex are rotational strains and compressive forces during flexion. Each episode of back pain causes posterior joint (facet) and annular (disc) strain. This leads to splinting of the posterior joints by the inherent musculature. Eventually, the muscles become ischemic (oxygen depletion) from acquired fatigue and this cause more pain by altering the muscular metabolism.
Because of small capsular (facet) and annular (disc) tears, a small degree of joint dysfunction takes place. Sustained facets dysfunction also leads to capsular synovitis (inflammation of the capsule of the facet joints), thus complicating matters even further.
2. Instability Phase
With each successive episodes of trauma, healing of capsular tears of the posterior joint and annular tears of the disc is less complete because the collagen of scar tissue is not as strong as normal collagen. The three parts of the three-joint complex are thus increasingly at risk.
During this phase, there is a tendency for the problem to reoccur, and on each occasion, the instability becomes more marked. The result is increased altered biomechanics through augmented structural degeneration of the cartilage surfaces of the facet joints leading to their deformation. This also yields to further joint laxity from capsular attenuation and ligamentous failure.
From a discal perspective, sustained segmental dysfunction leads to a coalescence of annular tears resulting in a loss of the nuclear integrity within the disc. With continued internal disruption of a disc, bulging or a herniation of the disc is anticipated over time.
3. Stabilization Phase
The end of the spectrum of spinal degeneration. In this phase, three mechanisms are at work. Stiffness of the posterior joints is increased because of destruction of the articular cartilage, fibrosis (scar tissue formation) within the joint occurs, with subsequent enlargement and locking of the facets. Periarticular fibrosis couple with osteophytosis (bone spurs) also contributes to spinal hypomobility and subsequent fusion.
Frequently, patients with back pain that was severe over past years becomes less incapacitating as a result of further structural stabilization and decreased spinal loading from reduced activity from advanced age groups. Appreciating how the three-joint complex is affected by the phases of degeneration is a fundamental concept and a natural bridge to the selection of treatment options.
Prevention is the key in minimizing the degenerative effects of the three joint complex. While maintaining optimized biomechanics through skilled chiropractic procedures coupled with regular exercise, this remains imperative to the maintenance of good spinal health. With repeated back pain episodes, one will migrate from a dysfunction phase to an instability phase and vice-versa.
The stabilization phase is usually attained later in life with advanced age groups. Consequently, it is important to monitor the evolution of the degenerative spondylosis in view of minimizing its progression through proper spinal correction and active rehabilitation. Sustained altered function within the three-joint complex leads to inevitable functional pathology.
Periodic assessment in the dysfunctional phase provides means to assess the three-joint complex and offers corrective measures without progression to the instability phase (advanced form of degenerative process). Chronic back pain patients are among the most difficult and challenging patients to manage. With an understanding of the three-joint complex, along with the three phases of the degeneration process, treatment options are simplified and this will avoid unnecessary therapeutic measures, thus favouring a better outcome for the long-term prognosis.