The study protocol was approved by the Institutional Review Board of New York Chiropractic College. It was also reviewed by the Health Insurance Portability and Accountability Act (HIPAA) compliance officer of the facility at which the data were gathered and was deemed to be in compliance with HIPAA regulations. All subjects signed informed consent forms, agreeing to have their data included in the study.
Cross-sectional data were gathered on consecutive patients seen at the Rhode Island Spine Center between 2/7/08 and 2/26/09.
All examinations were carried out by one of two chiropractic physicians, one with over 20 years experience and the other with nine years experience, or by a physical therapist with over 10 years experience. All had a minimum of 50 hours of postgraduate training in the McKenzie method. The physical therapist also had 80 hours of postgraduate training in manual therapy. Several discussions between the examiners took place over the course of five years prior to commencing data gathering on the application of the DBCDG. This occurred in the form of monthly clinical meetings in which the application of the DBCDG in particular patients was discussed as well as recent developments in the literature related to the evaluation and management of patients with NP. History and examination were performed according to the usual course of patient care at the Rhode Island Spine Center. These data, along with patient demographic data, and data from standardized outcome measurement instruments were then entered on a spreadsheet by a chiropractic intern. The standardized outcome measurement instruments were those tools used in the normal course of patient care at the facility at which the study was conducted to measure improvement in pain and perceived disability. These instruments were the Bournemouth Disability Questionnaire (BDQ) [14
] and Numerical Rating Scale [16
] for pain intensity.
Details of the proposed DBCDG are published elsewhere [8
] but the approach is based on three questions of diagnosis:
1. Are the symptoms with which the patient is presenting reflective of a visceral disorder or a serious or potentially life-threatening disease?
The purpose of this question is to identify signs and symptoms suggestive of non-musculoskeletal problems for which NP may be among the initial symptoms. Gastrointestinal and anterior neck disorders are included in addition to such "red flag" disorders as fracture, infection and malignancy.
2. From where is the patient's pain arising?
In the majority of cases it is not possible to know with absolute certainty what the pain generating tissue is. However there is evidence that characteristics of the pain generating tissue can be reliably identified [17
] and that treatment decisions can be made based on these characteristics [10
3. What has gone wrong with this person as a whole that would cause the pain experience to develop and persist?
With this question the clinician seeks to identify factors that serve to perpetuate the ongoing pain and suffering experience. These factors may be somatic, neurophysiological or psychological. Often more than one perpetuating factor is identified.
Following each new patient encounter the answers to the three questions of diagnosis were documented on a standardized form (see Additional File 1
). The combined answers to the three questions of diagnosis are formulated into a working diagnosis (Figure ) from which a management strategy is derived (Figure ). In many cases, the working diagnosis is multifactorial, leading to a multi-modal management strategy.
Figure 1 Diagnostic algorithm for the application of the DBCDG. Adapted with permission from: Murphy DR, Hurwitz EL. A theoretical model for the development of a diagnosis-based clinical decision rule for the management of patients with spinal pain. BMC Musculoskelet (more ...)
Figure 2 Management algorithm for the application of the DBCDG. Reprinted with permission from: Murphy DR, Hurwitz EL. A theoretical model for the development of a diagnosis-based clinical decision rule for the management of patients with spinal pain. BMC Musculoskelet (more ...)
In seeking an answer to the first question of diagnosis, standard history and examination procedures were used. In cases in which it was warranted, such as the presence of red flags for fracture, dislocation, infection or malignancy, profound motor loss, or signs and symptoms reflective of visceral disease, special tests such as radiographs, MRI or blood tests were ordered [25
In seeking the answer to the second question of diagnosis, four signs are considered:
a. Centralization signs, detected via the McKenzie end-range loading examination. Details of this examination can be found elsewhere [27
] however the approach involves moving the cervical spine, either by patient- or examiner-generated maneuvers, to the end of the range of motion in various directions. A typical centralization sign is detected if movement in a certain direction causes progressive "centralization" of the patient's symptoms, i.e., movement of the symptoms from the periphery (upper extremity and/or scapula) to the axial spine. Also considered a centralization sign would be a progressive decrease in pain intensity even if movement of the pain to the center was not perceived.
b. Segmental pain provocation signs, detected via segmental palpation as described by Jull, et al [19
]. This involved the patient lying prone and the examiner using the hands to move the overlying tissues lateral to medial and applying pressure as close to zygapophyseal joint as possible. The presence of segmental pain provocation signs was based on the examiner perceiving increased resistance to this pressure relative to other segments and the patient reporting reproduction of the NP [19
]. In cases in which there was a discrepancy between the amount of resistance perceived by the examiner and reproduction of pain perceived by the patient, pain reproduction was given priority.
c. Neurodynamic signs, detected by tests designed to compress, decompress or stretch the cervical nerve roots [22
]. The cluster of tests that formed the core of this examination was a) the brachial plexus tension test, in which stretch is applied to the neural structures of the cervical spine and upper extremity to determine whether this reproduces the patient's pain (with localizing and sensitizing maneuvers applied for confirmation) [30
]; b) rotation to the side of symptoms being limited due to reproduction of pain; c) the cervical distraction test in which the head of the seated patient is move superiorward to distract the cervical spine and the patient is asked if this relieves pain, and d) the maximum cervical compression test in which the cervical spine of the seated patient is moved into lateral flexion toward the side of symptoms and slightly extended and pressure is applied to the top of the head to determine if this reproduces the patient's pain. Wainner, et al [22
] found that the presence of positive findings on three of these tests indicated at least a 65% probability of the presence of cervical radiculopathy. The presence of positive findings in all four tests increased the probability to 90%. This was reinforced by neurologic examination looking for nerve root-specific neurologic deficit although neurologic deficit was not necessary for the determination of the presence of neurodynamic signs.
d. Myofascial signs, detected by palpation [20
] in which the examiner searches for a taut band within a muscle and a nodular formation within the taut band (a trigger point). Pressure is applied to the nodule to determine if this reproduces the patient's pain. Trigger points can occur in latent form in individuals without pain and as such it is considered important to not only identify the presence of a trigger point but to determine whether it is diagnostically relevant in any given patient [33
]. Thus, these signs were only recorded if the clinician felt they were diagnostically relevant to the patient's NP.
In seeking answers to the third question of diagnosis, four factors were considered [8
1. Dynamic instability, detected through clinical tests of motor control for the cervical spine [34
]. Impairment of the motor control system has been theorized to lead to perpetuation of pain and disability as a result of ongoing microtrauma to the tissues of the spine [38
]. The primary test used for this purpose was the cervical stability test in which the head of the supine patient is held with the upper cervical spine slightly flexed and it is determined if the patient can maintain this position when the examiner lets go of the head [35
2. Oculomotor dysfunction. This is commonly associated with pain that occurs after cervical trauma in patients who experience delayed recovery [42
]. There is some evidence of a correlation between oculomotor dysfunction and findings on tests of head repositioning [45
] however the sensitivity and specificity are not very high [46
]. Other clinical tests have been proposed [47
] but these have not been assessed for reliability and validity. Thus, there is currently no clinical examination procedure that has been shown to have high clinical utility in detecting oculomotor dysfunction. However as oculomotor exercises have been shown to be effective [48
] it was felt that a decision-making criterion was needed by which to determine which patients should at least be suspected of potentially having oculomotor dysfunction. As oculomotor dysfunction has been associated with cervical trauma, this factor was recorded as positive in any patient whose NP arose from trauma.
3. Central pain hypersensitivity (CPH), detected through observation of pain behavior in response to stimuli as well as through cervical nonorganic signs [50
]. This was based on the findings of Fishbain, et al [51
] who reviewed the literature on nonorganic signs in patients with low back pain and found that these signs, in addition to predicting poor functional abilities and poor outcome to treatment, were associated with greater pain levels and that the majority of these signs can be explained on the basis of pain intensity. Intensity of chronic pain is thought to reflect central nervous system processes (termed here central pain hypersensitivity) in addition to peripheral processes [52
]. Because of this, these signs were only used in chronic NP patients and not in acute NP patients. However, the sensitivity and specificity of the use of nonorganic signs for suspected CPH is not known.
4. Psychological factors such as fear [53
], catastrophizing [54
], passive coping [55
], depression [56
] and poor self-efficacy [57
]. There is evidence that at least some of these factors co-exist in individual patients [57
] and that while it is likely best to measure more than one factor, it is not necessary to detect all of them in order to identify a significant psychological component to the clinical picture [61
]. Based on this, and consistent with the need to obtain quality information in the context of a busy clinical environment with minimal burden to the patient, measurement of all these factors, which would have necessitated each patient completing multiple questionnaires, was not undertaken. Three measures were used for the purpose of identifying fear beliefs, coping strategies and depression. Fear beliefs were measured using the 11-item Tampa Scale for Kinesiophobia (TSK) [62
]. A score of 27 was considered indicative of clinically meaningful fear beliefs. This number was adapted from Vlaeyen, et al [63
] who used a cutoff score 40 using a previous 17-item version of the TSK and Woby (personal communication 3 August, 2009) whose unpublished data suggested a score of 26 to 27 to be associated with clinically meaningful fear beliefs. In addition, two questions from the Coping Strategies Questionnaire [64
] which have previously been found to be predictive of changes in disability in LBP patients [65
] were used to measure patients' perception of their control over the pain. At the time of data collection, no data were available regarding whether a particular score with these questions constitutes a threshold for clinically meaningful difficulty with coping strategies, i.e., that score that represents a reasonable cutoff between the presence or absence of coping strategies that may perpetuate ongoing pain, suffering and disability. The depression subscale of the BDQ [15
] was used to measure depression. In the development of the BDQ, the question related to depression was found to correlate well with the Zung Depression scale [14
] and the Mental Health scale of the SF36 instrument [15
]. As with the coping strategies questions, no data are available by which to determine a threshold for clinically meaningful depression with this question.
Patients also completed the BDQ [15
] and the Numerical Rating Scale for pain intensity (NRS) [16