Case reportThe use of a mechanism-based classification system to evaluate and direct management of a patient with non-specific chronic low back pain and motor control impairment—A case report
Introduction
Low back pain (LBP) is one of the most common and costly musculoskeletal pain syndromes, affecting up to 80% of people at some point during their lifetime (Katz, 2002; van Tulder et al., 2002; Ehrlich, 2003; Woolf and Pfleger, 2003). It is reported that in spite of the large number of pathological conditions that can give rise to LBP, 85% of these are without a detected patho-anatomical/radiological abnormality. This population is classified as having ‘non-specific’ (NS) LBP (Waddell, 1987, Waddell, 2004; Dillingham, 1995) which often develops into a chronic fluctuating problem with intermittent flares (Croft et al., 1998; Burton et al., 2004).
Optimal treatment for patients with NS-CLBP remains largely enigmatic. Randomized Controlled Trials (RCTs) have failed to find consistent evidence for improved outcomes (Goldby et al., 2000; Cairns et al., 2002; Assendelft et al., 2004; Frost et al., 2004). One explanation offered for the inability to identify effective treatments is the lack of success in defining sub-groups of patients who are most likely to respond to a specific treatment approach (Leboeuf-Yde et al., 1997; Borkan et al., 1998; Bouter et al., 1998). Indeed, it has been proposed that the ‘LBP-group’ conceals a large heterogeneous group of patients (McKenzie, 1981; Spitzer, 1987; Borkan et al., 1998; Bouter et al., 1998; Leboeuf-Yde and Manniche, 2001). Any specific treatment applied to a falsely assumed homogenous sample may result in improvement, failure to respond or aggravation of the disorder (Binkley et al., 1993; Fritz et al., 2000; Leboeuf-Yde and Manniche, 2001; Fritz et al., 2003).
The shift from thinking about LBP as a patho-anatomical disorder, to viewing LBP as a multi-factorial bio-psycho-social disorder is now well accepted (Borkan et al., 2002; McCarthy et al., 2004; Waddell, 2004). Consequently, the different dimensions relevant to classifying the domain of LBP include patho-anatomical, signs and symptoms, psychological and social (Waddell, 1987; Ford et al., 2003). For LBP, several classification systems (CSs) from a multitude of perspectives have been proposed. A recent review highlights that the multi-dimensional nature of LBP is not reflected in most CSs (Ford et al., 2003; McCarthy et al., 2004).
While it is well recognized that altered motor control exists with LBP disorders, the changes in motor control in this population are highly variable (O’Sullivan et al., 1997; Hodges and Moseley, 2003; van Dieen et al., 2003). O’Sullivan reported that in general all disorders involving pain in the lumbar region are associated with movement or control impairment. The mere presence of these impairments does not imply that they represent the underlying basis for the disorder, or that correcting these impairments will result in resolving the disorder (O’Sullivan, 2004, O’Sullivan, 2005).
O’Sullivan's approach to classification is based on a process of ‘diagnostics’ (Elvey and O’Sullivan, 2004) to make a clinical determination as to whether the patient presents with a classification of motor control impairment (MCI) or whether the MCI is simply a secondary effect of another process. This process of diagnostics places a strong emphasis on the correlation between the subjective history, radiology, pain behaviour, physical examination findings and screens for serious pathology (‘red flags’) and psycho-social factors (‘yellow flags’).
According to O’Sullivan motor responses present with LBP can be classified into three distinct broad groups (O’Sullivan, 2005). The first group consists of subjects whose motor response is secondary (and adaptive) to an underlying pathological process. The second group consists of subjects where the motor response is secondary to a dominance of psychological and/or social (non-organic) factors. O’Sullivan (2005) proposed that a third group exists where maladaptive motor responses result in chronic abnormal tissue loading leading to ongoing pain and distress.
Five distinct (direction based) patterns of MCI have been previously described in detail (O’Sullivan, 2000, O’Sullivan, 2004). These sub-groups of MCI consist of the; flexion pattern, active extension pattern, passive extension pattern, lateral shifting pattern and a multi-directional pattern (Table 1).
Recently, Dankaerts et al. (2006a) showed that these sub-groups could be reliably identified by trained clinicians (physiotherapists and medical doctors). There is also growing support for the validity of these sub-groups with recent studies revealing altered spinal repositioning sense (O’Sullivan et al., 2003), different spinal posture, kinematics and muscle activation patterns among sub-groups consistent with the CS (Burnett et al., 2004; Dankaerts et al., 2006b, Dankaerts et al., 2006c; O’Sullivan et al., 2006). Despite this growing evidence, there is a lack of longitudinal studies documenting outcome on these specific sub-groups following a targeted intervention.
Synchronized recording of surface electromyography (sEMG) and spinal kinematics have been reported frequently in the literature as objective measurement methods in non-outcome LBP research (McGill et al., 1997; Callaghan et al., 1998; Peach et al., 1998; Callaghan and McGill, 2001; Green et al., 2002). This methodological approach has been shown to be sensitive to quantify parameters of motor control and to sub-classify NS-CLBP patients with MCI during sitting (Dankaerts et al., 2006b, Dankaerts et al., 2006c). An advantage of this form of measurement is that unlike simple range of motion (ROM), measures of sEMG and spinal kinematics have the capacity to quantify the quality and pattern of movement of the spinal-pelvic region through ROM.
The aim of this case report is to investigate the use of O’Sullivan's CS to evaluate and direct management of a patient with NS-CLBP and MCI. An objective laboratory-based assessment (using sEMG and spinal kinematics) was performed on a LBP patient and a matched pain-free control subject. The aim of the laboratory testing was to evaluate its capacity to lend support to the classification of MCI and to quantify the clinical changes in motor control secondary to a specific motor learning intervention.
Section snippets
Subjective and physical examination
A comprehensive subjective and physical examination was first performed on the patient in order to classify her disorder. This information is summarized in Table 2, Table 3, respectively.
Classification based on history and physical examination
It is acknowledged that rather than relying on one test, classification of a disorder should be based on information of the history taking examination and a ‘cluster of tests’ in combination with a reasoning process (Elvey and O’Sullivan, 2004). In this way, several key features of the physical examination findings (not one single test) consistent with the history, helped to formulate the hypothesis of a classification of multi-directional pattern of MCI disorder (O’Sullivan, 2004). The
Laboratory testing
An objective laboratory-based assessment (surface EMG and spinal kinematics) was performed on the patient and a matched control subject. The method of this laboratory testing has been described in detail elsewhere (Dankaerts et al., 2006b, Dankaerts et al., 2006c). This case study reports on the lumbo-sacral kinematics and the sEMG activity of superficial Lumbar Multifidus (sLM) and transverse fibres of Internal Oblique (trIO) during forward bending. This test was selected since it is
Intervention
The patient's management consisted of a motor learning intervention based on a cognitive behavioural model. It was progressed over a 14-week period (total of 8 visits, the first 3 were spaced 1 week apart, with subsequent sessions once every 2–3 weeks) to address the impairments in motor control of this patient in a functionally specific manner. The choice of this treatment approach was based on the diagnosis and classification assigned to this patient. Each session included re-evaluation and
Clinical outcome
The patient progressed well during the intervention with a gradual decrease in pain and an increase in functional ability. At 14 weeks (end of intervention) she reported to be pain-free with an ability to perform work and household-related tasks. This was associated with a normalization of her movement patterns and absence of pain, improved spinal proprioception, adoption of neutral zone postures and reduced tissue sensitivity. The Revised-Oswestry Disability Questionnaire (Hudson-Cook et al.,
Forward bending: range of motion
The patient's lumbar spine ROM into forward bending was 48° at the intake examination and 47° at 6-month follow-up. This confirms the clinically observed absence of any movement impairment into forward bending being related to her LBP. This is consistent with the CS.
Forward bending: kinematic pattern
Fig. 1 shows the lumbar curvature (L×C) in degrees as measured by the Fastrak™ in standing and per quartile as the subject bends forward. Negative values represent a lordotic posture. Fig. 1a represents a matched (age and parity)
Discussion
The patient described in this case report would be ‘classically’ diagnosed as having NS-CLBP based on the absence of any abnormal radiological findings linked to the clinical presentation (Waddell, 1987, Waddell, 2004; Dillingham, 1995). Based on the CS (O’Sullivan, 2004) this patient was classified as having a multi-directional pattern of MCI.
The use of a CS to guide management of patients with LBP and MCI has been reported previously (Maluf et al., 2000; Van Dillen et al., 2003). There are
Conclusion
This case study illustrates the use of O’Sullivan's CS to guide physiotherapy intervention for a patient with a classification of multi-directional MCI. The kinematic and EMG data support the classification and demonstrated pre-intervention an impairment in the control of the spine during functional movement tasks. Following a motor learning intervention the altered motor control was normalized and was associated with reductions in pain disability and movement-based fear. Ultimately, further
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