Howard Vernon

The Neck Disability Index: State-of-the-Art, 1991-2008

BACKGROUND Published in 1991, the Neck Disability Index (NDI) was the first instrument designed to assess self-rated disability in patients with neck pain. This article reviews the history of the NDI and the current state of the research into its psychometric properties--reliability, validity, and responsiveness--as well as its translations. Focused reviews are presented into its use in studies of the prognosis of whiplash-injured patients as well as its use in clinical trials of conservative therapies for neck pain. SPECIAL FEATURES The NDI is a relatively short, paper-pencil instrument that is easy to apply in both clinical and research settings. It has strong psychometric characteristics and has proven to be highly responsive in clinical trials. As of late 2007, it has been used in approximately 300 publications; it has been translated into 22 languages, and it is endorsed for use by a number of clinical guidelines. SUMMARY The NDI is the most widely used and most strongly validated instrument for assessing self-rated disability in patients with neck pain. It has been used effectively in both clinical and research settings in the treatment of this very common problem.

A Randomized Clinical Trial of Exercise and Spinal Manipulation for Patients With Chronic Neck Pain

Study Design. A randomized, parallel-group, single-blinded clinical trial was performed. After a 1-week baseline period, patients were randomized to 11 weeks of therapy, with posttreatment follow-up assessment 3, 6, and 12 months later. Objectives. To compare the relative efficacy of rehabilitative neck exercise and spinal manipulation for the management of patients with chronic neck pain. Summary of Background Data. Mechanical neck pain is a common condition associated with substantial morbidity and cost. Relatively little is known about the efficacy of spinal manipulation and exercise for chronic neck pain. Also, the combination of both therapies has yet to be explored. Methods. Altogether, 191 patients with chronic mechanical neck pain were randomized to receive 20 sessions of spinal manipulation combined with rehabilitative neck exercise (spinal manipulation with exercise), MedX rehabilitative neck exercise, or spinal manipulation alone. The main outcome measures were patient-rated neck pain, neck disability, functional health status (as measured by Short Form-36 [SF-36]), global improvement, satisfaction with care, and medication use. Range of motion, muscle strength, and muscle endurance were assessed by examiners blinded to patients’ treatment assignment. Results. Clinical and demographic characteristics were similar among groups at baseline. A total of 93% of the patients completed the intervention phase. The response rate for the 12-month follow-up period was 84%. Except for patient satisfaction, where spinal manipulative therapy and exercise were superior to spinal manipulation with (P = 0.03), the group differences in patient-rated outcomes after 11 weeks of treatment were not statistically significant (P = 0.13). However, the spinal manipulative therapy and exercise group showed greater gains in all measures of strength, endurance, and range of motion than the spinal manipulation group (P < 0.05). The spinal manipulation with exercise group also demonstrated more improvement in flexion endurance and in flexion and rotation strength than the MedX group (P < 0.03). The MedX exercise group had larger gains in extension strength and flexion–extension range of motion than the spinal manipulation group (P < 0.05). During the follow-up year, a greater improvement in patient-rated outcomes were observed for spinal manipulation with exercise and for MedX exercise than for spinal manipulation alone (P = 0.01). Both exercise groups showed very similar levels of improvement in patient-rated outcomes, although the spinal manipulation and exercise group reported greater satisfaction with care (P < 0.01). Conclusions. For chronic neck pain, the use of strengthening exercise, whether in combination with spinal manipulation or in the form of a high-technology MedX program, appears to be more beneficial to patients with chronic neck pain than the use of spinal manipulation alone. The effect of low-technology exercise or spinal manipulative therapy alone, as compared with no treatment or placebo, and the optimal dose and relative cost effectiveness of these therapies, need to be evaluated in future studies.

Effects of inflammatory irritant application to the rat temporomandibular joint on jaw and neck muscle activity

&NA; An electromyographic (EMG) study was carried out in 40 anaesthetized rats to determine if the activity of jaw and neck muscles could be influenced by injection of the small‐fibre excitant and inflammatory irritant mustard oil into the region of the temporomandibular joint (TMJ). Injection of a vehicle (mineral oil, 20 &mgr;l) did not produce any significant change in EMG activity. In contrast, injection of mustard oil (20 &mgr;l, 20%) evoked increases in EMG activity in the jaw muscles but not in the neck muscles. The increased EMG activity evoked by mustard oil was reflected in 1 or 2 phases of increased activity. The early EMG increase occurred soon after the mustard oil injection (mean latency ± SD: 3.5 ± 2.3 sec), peaked within 1 min, and then subsided (mean duration: 7.5 ± 5.2 min). The later EMG increase occurred at 14.6 ± 10.0 min after the mustard oil injection and lasted 14.3 ± 12.3 min. These excitatory effects of mustard oil on the EMG activity of jaw muscles appear to have a reflex basis since they could be abolished by pre‐administration of local anaesthetic into the TMJ region. These results document that TMJ injection of mustard oil results in a sustained and reversible activation of jaw muscles that may be related to the reported clinical occurrence of increased muscle activity associated with trauma to the TMJ.

Systematic review of randomized clinical trials of complementary/alternative therapies in the treatment of tension-type and cervicogenic headache

OBJECTIVES To conduct a systematic review of the randomized controlled clinical trials (RCTs) of complementary/alternative (CAM) therapies in the treatment of non-migrainous headache (i.e. excluding migraine, cluster and organic headaches). DESIGN Systematic review with quality scoring and evidence tables. MAIN OUTCOME MEASURES Number of RCTs per therapy, quality scores, evidence tables. RESULTS Twenty-four RCTs were identified in the categories of acupuncture, spinal manipulation, electrotherapy, physiotherapy, homeopathy and other therapies. Headache categories included tension-type (under various names pre-1988), cervicogenic and post-traumatic. Quality scores for the RCT reports ranged from approximately 30 to 80 on a 100 point scale. CONCLUSION RCTs for CAM therapies of the treatment of non-migrainous headache exist in the literature and demonstrate that clinical experimental studies of these forms of headache can be conducted. Evidence from a sub-set of high quality studies indicates that some CAM therapies may be useful in the treatment of these common forms of headache.

Chiropractic Management of Myofascial Trigger Points and Myofascial Pain Syndrome: A Systematic Review of the Literature

OBJECTIVES Myofascial pain syndrome (MPS) and myofascial trigger points (MTrPs) are important aspects of musculoskeletal medicine, including chiropractic. The purpose of this study was to review the most commonly used treatment procedures in chiropractic for MPS and MTrPs. METHODS The Scientific Commission of the Council on Chiropractic Guidelines and Practice Parameters (CCGPP) was charged with developing literature syntheses, organized by anatomical region, to evaluate and report on the evidence base for chiropractic care. This article is the outcome of this charge. As part of the CCGPP process, preliminary drafts of these articles were posted on the CCGPP Web site www.ccgpp.org (2006-8) to allow for an open process and the broadest possible mechanism for stakeholder input. PubMed, Excerpta Medica Database, Cumulative Index to Nursing and Allied Health Literature, and databases for systematic reviews and clinical guidelines were searched. Separate searches were conducted for (1) manual palpation and algometry, (2) chiropractic and other manual therapies, and (3) other conservative and complementary/alternative therapies. Studies were screened for relevance and rated using the Oxford Scale and Scottish Intercollegiate Guidelines Network rating system. RESULTS A total of 112 articles were identified. Review of these articles resulted in the following recommendations regarding treatment: Moderately strong evidence supports manipulation and ischemic pressure for immediate pain relief at MTrPs, but only limited evidence exists for long-term pain relief at MTrPs. Evidence supports laser therapy (strong), transcutaneous electrical nerve stimulation, acupuncture, and magnet therapy (all moderate) for MTrPs and MPS, although the duration of relief varies among therapies. Limited evidence supports electrical muscle stimulation, high-voltage galvanic stimulation, interferential current, and frequency modulated neural stimulation in the treatment of MTrPs and MPS. Evidence is weak for ultrasound therapy. CONCLUSIONS Manual-type therapies and some physiologic therapeutic modalities have acceptable evidentiary support in the treatment of MPS and TrPs.

Involvement of NMDA receptor mechanisms in jaw electromyographic activity and plasma extravasation induced by inflammatory irritant application to temporomandibular joint region of rats

&NA; The aim of this study was to examine the possible role of N‐methyl‐ d‐aspartate (NMDA) receptor mechanisms in responses induced by the small‐fibre excitant and inflammatory irritant mustard oil injected into the temporomandibular joint (TMJ) region of rats. The effects of the non‐competitive NMDA antagonist MK‐801 were tested on the mustard oil‐evoked increases in electromyographic (EMG) activity of the masseter and digastric muscles and Evans Blue plasma extravasation. Five minutes before the mustard oil injection, MK‐801 or its vehicle was administered systemically (i.v.), into the third ventricle (i.c.v.), or locally into the TMJ region. Compared with control animals receiving vehicle, the rats receiving MK‐801 at an i.v. dose of 0.5 mg/kg (n = 5) showed a significant reduction in the incidence and magnitude of EMG responses as well as in the plasma extravasation evoked by mustard oil; MK‐801 at an i.v. dose of 0.1 mg/kg (n = 5) had no significant effect on plasma extravasation or on the incidence and magnitude of EMG responses but did significantly increase the latency of EMG responses. An i.c.v. dose of 0.1 mg/kg (n = 5) or 0.01 mg/kg (n = 5) had no significant effect on plasma extravasation or incidence of EMG responses but did significantly reduce the magnitudes of the masseter EMG response; the 0.01 mg/kg dose also significantly increased the latency of the digastric EMG response. The magnitudes of both the masseter and digastric EMG responses were also significantly reduced by MK‐801 administered into the TMJ region at a dose of 0.1 mg/kg (n = 5) but not by 0.01 mg/kg (n = 5); neither dose significantly affected the incidence of EMG responses or the plasma extravasation. These data suggest that both central and peripheral NMDA receptor mechanisms may play an important role in EMG responses evoked by the small‐fibre excitant and inflammatory irritant mustard oil, but that different neurochemical mechanisms may be involved in the plasma extravasation induced by mustard oil.

Excitatory effects on neck and jaw muscle activity of inflammatory irritant applied to cervical paraspinal tissues

&NA; A study was carried out in 19 anaesthetized rats to determine if the electromyographic (EMG) activity of jaw and neck muscles could be influenced by injection of the inflammatory irritant mustard oil into deep paraspinal tissues surrounding the C1‐3 vertebrae. The EMG activity was recorded ipsilaterally in the digastric, masseter and trapezius muscles and bilaterally in deep neck muscles (rectus capitis posterior). In comparison with control (vehicle) injections, mustard oil (20 &mgr;l, 20%) injected into the deep paraspinal tissues induced significant increases in EMG activity in the neck muscles in all the animals and in the jaw muscles in the majority of the animals; the effects of mustard oil were more prominent in the former. The EMG response evoked by mustard oil injection was frequently reflected in two phases of enhanced activity. The early phase of the increase in EMG activity was usually initiated immediately following mustard oil injection (mean latency: 20.4 ± 17.7 sec) and lasted 1.6 ± 1.1 min. The second phase occurred 11.3 ± 7.6 min later and lasted 11.0 ± 8.1 min. Evans Blue extravasation was apparent in the deep paraspinal tissues surrounding the C1‐3 vertebrae after mustard oil injection, and histological examination showed that mustard oil injection induced an inflammatory reaction in the rectus capitis posterior muscle. These results document that injection of the inflammatory irritant mustard oil into deep paraspinal tissues results in a sustained and reversible activation of both jaw and neck muscles. Such effects may be related to the reported clinical occurrence of increased muscle activity associated with trauma to deep tissues.

Translation of the Neck Disability Index and validation of the Greek version in a sample of neck pain patients

BackgroundNeck pain is a highly prevalent condition resulting in major disability. Standard scales for measuring disability in patients with neck pain have a pivotal role in research and clinical settings. The Neck Disability Index (NDI) is a valid and reliable tool, designed to measure disability in activities of daily living due to neck pain. The purpose of our study was the translation and validation of the NDI in a Greek primary care population with neck complaints.MethodsThe original version of the questionnaire was used. Based on international standards, the translation strategy comprised forward translations, reconciliation, backward translation and pre-testing steps. The validation procedure concerned the exploration of internal consistency (Cronbach alpha), test-retest reliability (Intraclass Correlation Coefficient, Bland and Altman method), construct validity (exploratory factor analysis) and responsiveness (Spearman correlation coefficient, Standard Error of Measurement and Minimal Detectable Change) of the questionnaire. Data quality was also assessed through completeness of data and floor/ceiling effects.ResultsThe translation procedure resulted in the Greek modified version of the NDI. The latter was culturally adapted through the pre-testing phase. The validation procedure raised a large amount of missing data due to low applicability, which were assessed with two methods. Floor or ceiling effects were not observed. Cronbach alpha was calculated as 0.85, which was interpreted as good internal consistency. Intraclass correlation coefficient was found to be 0.93 (95% CI 0.84–0.97), which was considered as very good test-retest reliability. Factor analysis yielded one factor with Eigenvalue 4.48 explaining 44.77% of variance. The Spearman correlation coefficient (0.3; P = 0.02) revealed some relation between the change score in the NDI and Global Rating of Change (GROC). The SEM and MDC were calculated as 0.64 and 1.78 respectively.ConclusionThe Greek version of the NDI measures disability in patients with neck pain in a reliable, valid and responsive manner. It is considered a useful tool for research and clinical settings in Greek Primary Health Care.

Craniofacial inputs to upper cervical dorsal horn: Implications for somatosensory information processing

The aim of this study was to characterize the properties of somatosensory neurons in the first 2 cervical spinal dorsal horns (C1 and C2 DHs) and compare them with those previously described for the rostral subnucleus caudalis (rVc). A total of 74 nociceptive neurons classified as wide-dynamic-range (WDR) or nociceptive-specific (NS), as well as 72 low-threshold mechanoreceptive (LTM) neurons, was studied in urethane/chloralose-anesthetized rats. The majority of LTM neurons were located in laminae III/IV and had a small mechanoreceptive field (RF) that included the posterior face and cervical tissues. In contrast, the nociceptive neurons were located in laminae I/II or V/VI, and the RF of each C1 and C2 DH nociceptive neuron included a part of the face and in 47% of them the RF included a region supplied by upper cervical afferents. There was a gradual caudal shift in the neuronal RF from nasal/intraoral tissues towards the neck as recording sites progressed from rVc to C1 and C2 DHs. In contrast to LTM neurons, many C1 and C2 DH nociceptive neurons received mechanosensitive convergent afferent inputs from cervical and craniofacial deep tissues (e.g., tongue muscles or temporomandibular joint), and over 50% could be activated by hypoglossal (XII) nerve electrical stimulation. We propose that C1 and C2 DHs represent part of the caudal extension of the Vc, and that Vc and C1 and C2 DHs may act together as one functional unit to process nociceptive information from craniofacial and cervical tissues, including that from deep craniofacial tissues.

A RANDOMIZED, PLACEBO-CONTROLLED CLINICAL TRIAL OF CHIROPRACTIC AND MEDICAL PROPHYLACTIC TREATMENT OF ADULTS WITH TENSION-TYPE HEADACHE: RESULTS FROM A STOPPED TRIAL

OBJECTIVES Tension-type headache (TTH) is the most common headache experienced by adults in Western society. Only 2 clinical trials of spinal manipulation for adult tension-type headache have been reported, neither of which was fully controlled. In 1 trial, spinal manipulation was compared to amitriptyline. There is an urgent need for well-controlled studies of chiropractic spinal manipulation for TTH. This trial was stopped prematurely due to poor recruitment. The purposes of this report are (1) to describe the trial protocol, as it contained several novel features, (2) to report the limited data set obtained from our sample of completed subjects, and (3) to discuss the problems that were encountered in conducting this study. METHODS A randomized clinical trial was conducted with a factorial design in which adult TTH sufferers with more than 10 headaches per month were randomly assigned to four groups: real cervical manipulation + real amitriptyline, real cervical manipulation + placebo amitriptyline, sham cervical manipulation + real amitriptyline, and sham cervical manipulation + placebo amitriptyline. A baseline period of four weeks was followed by a treatment period of 14 weeks. The primary outcome was headache frequency obtained from a headache diary in the last 28 days of the treatment period. RESULTS Nineteen subjects completed the trial. In the unadjusted analysis, a statistically significant main effect of chiropractic treatment was obtained (-2.2 [-10.2 to 5.8], P = .03) which was just below the 3-day reduction set for clinical importance. As well, a clinically important [corrected] effect of the combined therapies was obtained (-9 [-20.8 [corrected] to 2.9], P = .13), but this did not achieve statistical significance. In the adjusted analysis, neither the main effects of chiropractic nor amitriptyline were statistically significant or clinically important; however, the effect of the combined treatments was -8.4 (-15.8 to -1.1) which was statistically significant (P = .03) and reached our criterion for clinical importance. CONCLUSION Although the sample size was smaller than initially required, a statistically significant and clinically important effect was obtained for the combined treatment group. There are considerable difficulties with recruitment of subjects in such a trial. This trial should be replicated with a larger sample.