Identifiers Suggestive of Clinical Cervical Spine Instability
From Physical Therapy Vol. 85, No. 9, September 2005, pp. 895-906
Clinical cervical spine instability is controversial and difficult to diagnose. Within the literature, no clinical or diagnostic tests that yield valid and reliable results have been described to differentially diagnose this condition. The purpose of this study was to attempt to obtain consensus on symptoms and physical examination findings that are associated with Clinical cervical spine instability.
The symptoms that reached the highest consensus among respondents were intolerance to prolonged static postures, fatigue and inability to hold head up, better with external support, including hands or collar, frequent need for self-manipulation, feeling of instability, shaking, or lack of control, frequent episodes of acute attacks, and sharp pain, possibly with sudden movements. The physical examination findings related to cervical instability that reached the highest consensus among respondents included poor coordination/neuromuscular control, including poor recruitment and dissociation of cervical segments with movement, abnormal joint play, motion that is not smooth throughout range (of motion), including segmental hinging, pivoting, or fulcruming, and aberrant movement.
Neck pain is a common musculoskeletal condition reportedly affecting 70% of people within their lifetime. Instability is one element of cervical pain and may contribute to the clinical presentation of various conditions, including cervicogenic headaches, chronic whiplash dysfunction, rheumatoid arthritis, osteoarthritis, and segmental degeneration. Situations involving trauma, genetic predisposition, disk degeneration, and surgery may compromise the stabilizing mechanisms of the cervical spine.
It has been suggested that different categories of cervical instability exist. Radiographically appreciable cervical spine instability (RACSI) may lead to compression of neural or vascular structures, pain, and neurological signs and symptoms. In most cases, Radiographically appreciable cervical spine instability reflects marked disruption of passive osseoligamentous anatomical constraints and hypermobility.
Panjabi proposed that spinal stability is a component of 3 interactive subsystems: passive, active, and neural. The 3 systems work in concert to provide dynamic stability during the application of external forces. Instability may occur when the active and neural subsystems fail to maintain control within the intervertebral neutral zone of the cervical spine. Unlike Radiographically appreciable cervical spine instability, dysfunction of the active and neural subsystems is more appropriately described as an abnormality of movement rather than hypermobility and can present indicators of instability in the absence of passive system (osseoligamentous) pathology. These indicators may include cervical pain, aberrant cervical movements, referred shoulder pain, radiculopathy or myelopathy, paraspinal muscle spasms, decreased cervical lordosis, tinnitus, pain during sustained postures, complaints of catching or locking, and altered range of motion. In addition, a history of major trauma or repetitive microtrauma may predate report of symptoms.
Within the literature, instability associated with active and neural cervical subsystem failure is identified as clinical cervical spine instability, but it also has been characterized as nonradiographic or minor cervical instability. Clinical cervical spine instability may demonstrate only subtle symptoms and clinical examination features and frequently normal radiographic findings. At present, although numerous diagnostic identifiers are suggested for clinical cervical spine instability, a valid and effective criterion standard does not exist. Consequently, the condition is speciously associated with degeneration, kinematic measurements of anterior to posterior shear, abnormal or excessive coupling of the cervical spine, and unquantifiable physical examination findings.
The Delphi survey participants consensually selected symptoms that were qualitatively grouped by the work group members into 5 conceptually similar areas: (1) movements, (2) descriptive components, (3) postures, (4) neurological phenomena, and (5) headaches. Movement-related identifiers included sharp pain, possibly with sudden movements, neck gets stuck, or locks, with movement, and trivial movements provoke symptoms. In addition, unwillingness, apprehension, or fear of movement was identified, a finding supported by Klein et al, who reported an unwillingness of patients with whiplash-associated disorders to move their neck beyond comfort zones into ranges where higher muscle activity is engaged.
Descriptive components included identifiers that describe the type of pain or an action that modulates the pain. Within this category, the Delphi survey participants selected past history of neck dysfunction or trauma, better with external support, including hands or collar, frequent need for self-manipulation, feeling of instability, shaking, or lack of control, frequent episodes of acute attacks, head feels heavy, catching, clicking, clunking, and popping sensation, muscles feel tight or stiff, temporary improvement with clinical manipulation, and increased pain as day progresses. Several authors have identified the coexistence of trauma and cervical spine instability. Other authors have related cervical spine instability with comorbidities, such as spondylosis or spine degeneration, although these relationships appear less definitive. These studies did not determine whether the instability condition was radiographically appreciable.
Postural identifiers included intolerance to prolonged static postures and better in unloaded position such as lying down findings supported by other authors. Lying down may reduce intolerance to segmental physiological loading, as reported by Oxland and Panjabi Mid-postural position of the cervical spine displayed the highest area of load sensitivity. Hypothetically, mid-position is the posture that requires the most dynamic control of the neutral zone and is the position most prone to instability problems. Subjects with long-term rheumatologic-related instability show changes in muscle fibers, which can lead to losses of postural stability and decreased control of the neutral zone.
The Delphi survey respondents were undecided about spinal cord symptoms with neck movement or complaints of headache as specific identifiers of clinical cervical spine instability in our study. Past studies have suggested that cervical myelopathy and radiculopathy are associated with cervical spine instability. Most authors who have evaluated cord-related and radicular symptoms related to cervical spine instability have done so following severe trauma or dislocation of the cervical spine. Still, some symptomatic complaints may be related to repeated episodes of severe neck pain with minor provocation and may be less obviously deduced. Moreover, several authors have suggested the relationship between headaches and instability, most notably secondary to instability within the upper cervical spine as well as the C5–6 intervertebral disk.
