What Does Local Tenderness Say About the Origin of Pain? An Investigation of Cervical Zygapophysial Joint Pain

Testing Biological and Psychological Pathways of Emotion Regulation as a Primary Mechanism of Action in Yoga Interventions for Chronic Low Back Pain: Protocol for a Randomized Controlled Trial

BACKGROUND

Interventions that promote adaptive emotion regulation (ER) skills reduce pain in patients with chronic pain; however, whether the effects of yoga practice on chronic low back pain (CLBP) are due to improvements in ER remains to be examined.

OBJECTIVE

This study will test whether the effects of yoga on CLBP (improved pain severity and interference) are mediated by improved ER, the extent to which effects are related to specific aspects of ER, and the role of pain sensitization as a mediator or moderator of effects. In this study, pain sensitization will be assessed by quantitative sensory testing and gene expression profiles to examine whether pain sensitization moderates yoga's effects on pain or whether yoga and ER abilities reduce pain sensitization, leading to decreased pain severity and interference.

METHODS

For this 2-arm parallel group blinded randomized controlled trial, we will enroll 204 adults with CLBP who will be randomized to receive the yoga (n=102) or a control stretching and strengthening (n=102) intervention, which are delivered via web-based synchronous biweekly 75-minute sessions over 12 weeks. Participants are encouraged to practice postures or exercises for 25 minutes on other days using accessible prerecorded practice videos that are sent to participants digitally. Participants will be assessed at 5 time points: baseline, midintervention (6 weeks), postintervention (12 weeks), and 3- and 6-month follow-ups. Assessments of ER, pain severity and interference, pain sensitivity including somatosensory and gene expression profiles, and physical strength and flexibility will be conducted at each visit. The fidelity of the interventions is assessed using a manualized checklist to evaluate recorded group sessions to ensure consistent instructor delivery.

RESULTS

The primary outcome will be the mean change in pain severity as measured by the Brief Pain Inventory-Short Form at 12 weeks. The primary mechanism of action is ER measured by change in the Difficulties in Emotion Regulation Scale total score. Secondary outcomes include pain sensitivity, physical strength and flexibility, pain interference, and quality of life. A mediation path analysis and series of moderated mediation path analyses will be conducted to test the study hypotheses. As of January 2024, we have enrolled 138 participants. We expect the study to be completed by May 2025.

CONCLUSIONS

The study will provide important data for evaluating whether improvements in ER are responsible for reduced pain perception and pain sensitivity as well as increased quality of life in the context of chronic pain. The study findings have important implications for determining the mechanism of action for yoga and possibly other mind-body interventions as nonpharmacological therapies for pain management. The results of the study will inform the content, delivery, and measures for intervention trials involving yoga as a modality for relieving pain and improving function.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04678297; https://clinicaltrials.gov/study/NCT04678297.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/56016.

An unusual presentation of acute myocardial infarction in physiotherapy direct access: findings from a case report

BACKGROUND

Shoulder pain (SP) may originate from both musculoskeletal and visceral conditions. Physiotherapists (PT) may encounter patients with life-threatening pathologies that mimic musculoskeletal pain such as Acute Myocardial Infarction (AMI). A trained PT should be able to distinguish between signs and symptoms of musculoskeletal or visceral origin aimed at performing proper medical referral.

CASE PRESENTATION

A 46-y-old male with acute SP lasting from a week was diagnosed with right painful musculoskeletal shoulder syndrome, in two successive examinations by the emergency department physicians. However, after having experienced a shift of the pain on the left side, the patient presented to a PT. The PT recognized the signs and symptoms of visceral pain and referred him to the general practitioner, which identified a cardiac disease. The final diagnosis was acute myocardial infarction.

CONCLUSION

This case report highlights the importance of a thorough patient screening examination, especially for patients treated in an outpatient setting, which allow distinguishing between signs and symptoms of musculoskeletal from visceral diseases.

Medial Branch Blocks for Diagnosis of Facet Joint Pain Etiology and Use in Chronic Pain Litigation

A commonly disputed medicolegal issue is the documentation of the location, degree, and anatomical source of an injured plaintiff’s ongoing pain, particularly when the painful region is in or near the spine, and when the symptoms have arisen as result of a relatively low speed traffic crash. The purpose of our paper is to provide health and legal practitioners with strategies to identify the source of cervical pain and to aid triers of fact (decision makers) in reaching better informed conclusions. We review the medical evidence for the applications and reliability of cervical medial branch nerve blocks as an indication of painful spinal facets. We also present legal precedents for the legal admissibility of the results of such diagnostic testing as evidence of chronic spine pain after a traffic crash. Part of the reason for the dispute is the subjective nature of pain, and the fact that medical documentation of pain complaints relies primarily on the history given by the patient. A condition that can be documented objectively is chronic cervical spine facet joint pain, as demonstrated by medial branch block (injection). The diagnostic accuracy of medial branch blocks has been extensively described in the scientific medical literature, and evidence of facet blocks to objectively document chronic post-traumatic neck pain has been accepted as scientifically reliable in courts and tribunals in the USA, Canada and the United Kingdom. We conclude that there is convincing scientific medical evidence that the results of cervical facet blocks provide reliable objective evidence of chronic post-traumatic spine pain, suitable for presentation to an adjudicative decision maker.

A description of the primary studies of diagnostic test accuracy indexed on the DiTA database

BACKGROUND AND PURPOSE

PEDro (the Physiotherapy Evidence Database) is a widely used, comprehensive, freely available, online database that indexes studies of the effectiveness of physiotherapy interventions. We have recently built another database, called DiTA, on the same platform as PEDro. DiTA provides a comprehensive index of studies of the accuracy of diagnostic tests used by physiotherapists. This study aims to describe the number and scope of such studies.

METHODS

A comprehensive search was conducted for studies of the accuracy of diagnostic tests. The search was conducted on the MEDLINE, EMBASE and CINAHL databases from their inceptions to November 2018. Subsequently, monthly searches have updated the database. To be included on DiTA, studies need to investigate (a) both a pathology and patients that a physiotherapist could assess in clinical practice, and (b) an index test that a physiotherapist would perform themselves rather than one which they would request.

RESULTS

To date, the searches have yielded 44,884 titles. Screening has identified 1,419 reports that meet the inclusion criteria. The most frequently studied subdisciplines are "musculoskeletal" (1,050/1,419; 74.0%) and "cardiothoracics" (241; 17.0%); the most frequently studied categories of pathologies are joint pathologies (463; 32.6%) and nervous system pathologies (175; 12.3%); and the most frequently studied body part is the "lower leg or knee" (232; 16.3%). Most studies investigate index tests which are "physical examination" procedures (851; 60.0%); fewer investigate "questions or questionnaires" (420; 29.6%) and "health technologies" (351; 24.7%).

DISCUSSION

There is a rapidly growing body of evidence on the accuracy of diagnostic tests relevant to most physiotherapy subdisciplines. While the volume of evidence is substantial, it is not yet clear how much of the evidence is of good enough quality to support clinical decision-making.

Local and Widespread Pressure Pain Hyperalgesia Is Not Side Specific in Females with Unilateral Neck Pain that Can Be Reproduced during Passive Neck Rotation

Current evidence for widespread hyperalgesia in non-specific neck pain (NSNP) is unclear. It is currently recommended to group NSNP patients according to pain-provoking movements. The aim of this study was to investigate local and widespread pain sensitivity in females with unilateral NSNP that is reproducible during passive neck rotation compared with matched controls, and to compare the side specific effect of pain location on pressure pain sensitivity among females with unilateral NSNP. Thirty-six females with unilateral NSNP evoked during passive ipsilateral (n = 20) or contralateral (n = 16) rotation toward the painful side were compared with 20 controls. Participants reported their pain intensity at rest and during passive neck rotation and completed the Neck Disability Index. Pressure pain thresholds (PPTs) were assessed bilaterally over the anterior scalene; the sternocleidomastoid; the levator scapulae; lateral to the spinous process of C6; the median, ulnar, and radial nerves; and the tibialis anterior. The ANOVA revealed lower PPTs in females with unilateral NSNP compared with the controls (all at p < 0.001), but no differences were found between the sides, nor was there any Group × side interaction. Among females with NSNP, those with higher pain intensity during ipsilateral rotation toward the painful side showed lower PPTs over the anterior scalene, median nerve, ulnar nerve, and tibialis anterior (all, p < 0.05) than females with higher pain intensity during contralateral rotation toward the painful side. These findings demonstrated bilateral local and widespread pressure pain hyperalgesia in females with unilateral NSNP that was reproducible during passive neck rotation compared with controls. There was no side specific effect of pain location on PPTs among females with unilateral NSNP.

Clinical Diagnostic Tests versus Medial Branch Blocks for Adults with Persisting Cervical Zygapophyseal Joint Pain: A Systematic Review and Meta-Analysis

Purpose: A systematic review and meta-analysis were performed to identify clinical tests for diagnosing cervical zygapophyseal joint pain (CZP) and to determine their diagnostic accuracy. Method: A search strategy was carried out to find relevant evidence published in CINAHL, Embase, MEDLINE, and PEDro from 1980 to January 1, 2015, pertaining to the clinical diagnosis of CZP. Quality assessment was completed using the Quality Assessment of Diagnostic Accuracy Studies-2. Results were analyzed to pool sensitivity and specificity and clarify diagnostic value. Results: Seven articles (n=463) were included for data synthesis and review. Intersegmental mobility tests were found to have the highest diagnostic accuracy, with pooled sensitivity of 0.91 (95% CI: 0.85, 0.94) and specificity of 0.74 (95% CI: 0.65, 0.81). The pooled sensitivity for mechanical sensitivity (palpation) was 0.88 (95% CI: 0.78, 0.95), and specificity was 0.61 (95% CI: 0.50, 0.71). Conclusion: Limited studies are available that discuss the clinical diagnosis of CZP, and significant heterogeneity is present in the available data. In this review, intersegmental mobility tests were found to be the most accurate. Clustering of tests, agreement on a reference standard, and further exploration of CZP referral patterns are recommended.

Contextual modulation of pain sensitivity utilising virtual environments

BACKGROUND

Investigating psychological mechanisms that modulate pain, such as those that might be accessed by manipulation of context, is of great interest to researchers seeking to better understand and treat pain. The aim of this study was to better understand the interaction between pain sensitivity, and contexts with inherent emotional and social salience - by exploiting modern immersive virtual reality (VR) technology.

METHODS

A within-subjects, randomised, double-blinded, repeated measures (RM) design was used. In total, 25 healthy participants were exposed to neutral, pleasant, threatening, socially positive and socially negative contexts, using an Oculus Rift DK2. Pressure pain thresholds (PPTs) were recorded in each context, as well as prior to and following the procedure. We also investigated whether trait anxiety and pain catastrophisation interacted with the relationship between the different contexts and pain.

RESULTS

Pressure pain sensitivity was not modulated by context (p = 0.48). Anxiety and pain catastrophisation were not significantly associated with PPTs, nor did they interact with the relationship between context and PPTs.

CONCLUSION

Contrary to our hypothesis, socially and emotionally salient contexts did not influence pain thresholds. In light of other research, we suggest that pain outcomes might only be tenable to manipulation by contextual cues if they specifically manipulate the meaning of the pain-eliciting stimulus, rather than manipulate psychological state generally - as per the current study. Future research might exploit immersive VR technology to better explore the link between noxious stimuli and contexts that directly alter its threat value.

Pharmacological and Interventional Management of Pain After Whiplash Injury

Synopsis Whiplash-associated disorder (WAD) is a group of symptoms and clinical manifestations resulting from rear-end or side impact. Despite the wide use of medications in WAD, the published research does not allow recommendations based on high evidence level. It may be meaningful to use nonsteroidal anti-inflammatory drugs in the acute posttraumatic phase. In chronic WAD, the use of nonsteroidal anti-inflammatory drugs is more concerning due to potential gastrointestinal and renal complications with prolonged use and lack of evidence for long-term benefits. Antidepressants can be used in patients with clinically relevant hyperalgesia, sleep disorder associated with pain, or depression. Anticonvulsants are unlikely first-choice medications, but can be considered if other treatments fail. The use of opioids in patients with chronic pain has become the object of severe concern, due to the lack of evidence for long-term benefits and the associated risks. Extreme caution in prescribing and monitoring opioid treatment is mandatory. Nerve blocks of the zygapophyseal (facet) joints have validity for the diagnosis of facet joint pain, which is one of the possible manifestations of WAD. One randomized sham-controlled trial and several high-quality prospective studies support the efficacy of radiofrequency neurotomy for the treatment of facet joint pain. The efficacy of trigger point treatments is uncertain. They can be offered due to possible efficacy and limited risks. Any medication or procedure has to be considered in the frame of a comprehensive patient evaluation. As for any chronic pain condition, concomitant consideration of rehabilitation and psychosocial interventions is mandatory. J Orthop Sports Phys Ther 2016;46(10):845-850. Epub 3 Sep 2016. doi:10.2519/jospt.2016.6906.

Cervical zygapophysial (facet) joint pain: effectiveness of interventional management strategies

Diagnostic facet joint nerve blocks have been utilized in the diagnosis of cervical facet joint pain in patients without disk herniation or radicular pain due to a lack of reliable noninvasive diagnostic measures. Therapeutic interventions include intra-articular injections, facet joint nerve blocks and radiofrequency neurotomy. The diagnostic accuracy and effectiveness of facet joint interventions have been assessed in multiple diagnostic accuracy studies, randomized controlled trials (RCTs), and systematic reviews in managing chronic neck pain. This assessment shows there is Level II evidence based on a total of 11 controlled diagnostic accuracy studies for diagnosing cervical facet joint pain in patients without disk herniation or radicular pain utilizing controlled diagnostic blocks. Due to significant variability and internal inconsistency regarding prevalence in a heterogenous population; despite 11 studies, evidence is determined as Level II. Prevalence ranged from 36% to 67% with at least 80% pain relief as the criterion standard with a false-positive rate ranging from 27% to 63%. The evidence is Level II for the long-term effectiveness of radiofrequency neurotomy and facet joint nerve blocks in managing cervical facet joint pain. There is Level III evidence for cervical intra-articular injections.

Effectiveness of intra-articular steroid injection for atlanto-occipital joint pain

OBJECTIVES

The aims of this study were to evaluate the role of intra-articular joint injection for atlanto-occipital (AO) joint pain and to determine pain referral sites from that joint.

DESIGN

Prospective observational study.

METHOD

We evaluated 29 patients with chronic refractory neck pain and/or headache, and limited range of lateral bending with rotation at the AO joint on physical examination. Of the 24 patients who consented to undergo diagnostic injections, 20 patients had at least 50% relief from pain and underwent two AO intra-articular injections of mixture of local anesthetic and steroid approximately 1 week apart. Patients completed pain drawings, visual analog scales (VASs) for pain, and neck disability index (NDI) for level of function. Patients were evaluated for 2 months after the first injection.

RESULT

There was headache in 14/20 (70%), posterior neck pain (PNP) in 20, and referred pain in 17 (85%). The average VAS values for headache, PNP, and other referred pains were reduced significantly from 5.64, 5.70, and 5.41, respectively, before treatments to 0.64, 2.30, and 1.71, respectively, two months after injection (P < 0.01). The average NDI value was reduced significantly from 39.95% at pretreatment to 20.40% at 2 months after treatment (P < 0.01).

CONCLUSION

AO intra-articular steroid injection appears effective for the short-term control of chronic refractory pain arising from the AO joint.

Frequency of discordance between facet joint activity on technetium Tc99m methylene diphosphonate SPECT/CT and selection for percutaneous treatment at a large multispecialty institution

BACKGROUND AND PURPOSE

The clinical impact of facet joint bone scan activity is not fully understood. The hypothesis of this study is that facet joints targeted for percutaneous treatment in clinical practice differ from those with reported activity on technetium Tc99m methylene diphosphonate SPECT/CT.

MATERIALS AND METHODS

All patients with a technetium Tc99m methylene diphosphonate SPECT/CT scan of the lumbar or cervical spine who underwent subsequent percutaneous facet joint steroid injection or comparative medial branch blocks at our institution between January 1, 2008, and February 19, 2013, were identified. Facet joints with increased activity were compared with those treated. A chart review characterized the clinical reasons for treatment discrepancies.

RESULTS

Of 74 patients meeting inclusion criteria, 52 (70%) had discrepant imaging findings and treatment selection of at least 1 facet joint, whereas 34 patients (46%) had a side (right vs left) discrepancy. Only 92 (70%) of 132 facet joints with increased activity were treated, whereas 103 (53%) of 195 of treated facet joints did not have increased activity. The most commonly documented clinical rationale for discrepancy was facet joint activity that was not thought to correlate with clinical findings, cited in 18 (35%) of 52 patients.

CONCLUSIONS

Facet joints undergoing targeted percutaneous treatment were frequently discordant with those demonstrating increased technetium Tc99m methylene diphosphonate activity identified by SPECT/CT at our institution, in many cases because the active facet joint(s) did not correlate with clinical findings. Further prospective double-blinded investigations of the clinical significance of facet joint activity by use of technetium Tc99m methylene diphosphonate SPECT/CT and comparative medial branch blocks are needed.

A simulated passive intervertebral motion task: observations of performance in a cross-sectional study

INTRODUCTION

Passive motion palpation is an integral component in examination, diagnosis or classification, and treatment of persons with mechanical disorders of the cervical spine. If the magnitude of force application during passive movement assessment is associated with greater palpatory accuracy has not been established.

METHODS

This investigation used a novel mechanical model as a basis for assessing the palpatory force of students and clinicians. The model included multiple palpable resistance and displacement levels similar to that observed in humans. The ability of the subjects to discriminate the various levels of resistance and displacement offered by the model was concurrently measured.

RESULTS

Large variability occurred in the amount of force applied by the subjects in completing the palpatory examination. The data indicated no major differences in palpatory accuracy across the student and clinician groups with different training and experience levels beyond basic competency. Those subjects applying less force in the palpatory exam demonstrated greater accuracy of palpatory assessment with one measure.

DISCUSSION

The data indicate training and experience had minimal relationship to palpatory interpretation precision beyond the basic level and individual natural discriminatory ability may be a factor in accuracy of palpatory skill. The results demonstrate remarkable inconsistency in palpatory force among examiners and suggest that palpatory accuracy may be related to less force application.

Relationship between quantitative sensory testing and pain or disability in people with spinal pain-a systematic review and meta-analysis

Sensitization of the nervous system can present as pain hypersensitivity that may contribute to clinical pain. In spinal pain, however, the relationship between sensory hypersensitivity and clinical pain remains unclear. This systematic review examined the relationship between pain sensitivity measured via quantitative sensory testing (QST) and self-reported pain or pain-related disability in people with spinal pain. Electronic databases and reference lists were searched. Correlation coefficients for the relationship between QST and pain intensity or disability were pooled using random effects models. Subgroup analyses and mixed effects meta-regression were used to assess whether the strength of the relationship was moderated by variables related to the QST method or pain condition. One hundred and forty-five effect sizes from 40 studies were included in the meta-analysis. Pooled estimates for the correlation between pain threshold and pain intensity were -0.15 (95% confidence interval [CI]: -0.18 to -0.11) and for disability -0.16 (95% CI: -0.22 to -0.10). Subgroup analyses and meta-regression did not provide evidence that these relationships were moderated by the QST testing site (primary pain/remote), pain condition (back/neck pain), pain type (acute/chronic), or type of pain induction stimulus (eg, mechanical/thermal). Fair correlations were found for the relationship between pain intensity and thermal temporal summation (0.26, 95% CI: 0.09 to 0.42) or pain tolerance (-0.30, 95% CI: -0.45 to -0.13), but only a few studies were available. Our study indicates either that pain threshold is a poor marker of central sensitization or that sensitization does not play a major role in patients' reporting of pain and disability. Future research prospects are discussed.

Head pain referral during examination of the neck in migraine and tension-type headache

OBJECTIVE

To investigate if and to what extent typical head pain can be reproduced in tension-type headache (TTH), migraine without aura sufferers, and controls when sustained pressure was applied to the lateral posterior arch of C1 and the articular pillar of C2, stressing the atlantooccipital and C2-3 segments respectively.

BACKGROUND

Occipital and neck symptoms often accompany primary headache, suggesting involvement of cervical afferents in central pain processing mechanisms in these disorders. Referral of head pain from upper cervical structures is made possible by convergence of cervical and trigeminal nociceptive afferent information in the trigemino-cervical nucleus. Upper cervical segmental and C2-3 zygapophysial joint dysfunction is recognized as a potential source of noxious afferent information and is present in primary headache sufferers. Furthermore, referral of head pain has been demonstrated from symptomatic upper cervical segments and the C2-3 zygapophysial joints, suggesting that head pain referral may be a characteristic of cervical afferent involvement in headache.

METHODS

Thirty-four headache sufferers and 14 controls were examined interictally. Headache patients were diagnosed according the criteria of the International Headache Society and comprised 20 migraine without aura (females n = 18; males n = 2; average age 35.3 years) and 14 TTH sufferers (females n = 11; males n = 3; average age 30.7 years). Two techniques were used specifically to stress the atlantooccipital segments (Technique 1 - C1) and C2-3 zygapophysial joints (Technique 2 - C2). Two techniques were also applied to the arm--the common extensor origin and the mid belly of the biceps brachii. Participants reported reproduction of head pain with "yes" or "no" and rated the intensity of head pain and local pressure of application on a scale of 0 -10, where 0 = no pain and 10 = intolerable pain.

RESULTS

None of the subjects reported head pain during application of techniques on the arm. Head pain referral during the cervical examination was reported by 8 of 14 (57%) control participants, all TTH patients and all but 1 migraineur (P < .002). In each case, participants reported that the referred head pain was similar to the pain they usually experienced during TTH or migraine. The frequency of head pain referral was identical for Techniques 1 and 2. The intensity of referral did not differ between Technique 1 and Technique 2 or between groups. Tenderness ratings to thumb pressure were comparable between the Techniques 1 and 2 when pressure was applied to C1 and C2 respectively and across groups. Similarly, there were no significant differences for tenderness ratings to thumb pressure between Technique 1 and Technique 2 on the arm or between groups. While tenderness ratings to thumb pressure for Technique 2 were similar for both referral (n = 41) and non-referral (n = 7) groups, tenderness ratings for Technique 1 in the referral group were significantly greater when compared with the non-referral group (P = .01).

CONCLUSIONS

Our data support the continuum concept of headache, one in which noxious cervical afferent information may well be significantly underestimated. The high incidence of reproduction of headache supports the evaluation of musculoskeletal features in patients presenting with migrainous and TTH symptoms. This, in turn, may have important implications for understanding the pathophysiology of headache and developing alternative treatment options.

A descriptive study of pressure pain threshold at 2 standardized sites in people with acute or subacute neck pain

STUDY DESIGN

Cross-sectional convenience sample.

OBJECTIVES

To describe the distribution of scores for pressure pain threshold (PPT) at 2 standardized testing sites in people with neck pain of less than 90 days' duration: the angle of the upper trapezius and the belly of the tibialis anterior. A secondary objective was to identify important influences on PPT.

BACKGROUND

PPT may be a valuable assessment and prognostic indicator for people with neck pain. However, to facilitate interpretation of scores, knowledge of means and variance for the target population, as well as factors that might influence scores, is needed.

METHODS

Participants were recruited from community-based physiotherapy clinics and underwent PPT testing using a digital algometer and standardized protocol. Descriptive statistics (mean, standard deviations, quartiles, skewness, and kurtosis) were calculated for the 2 sites. Simple bivariate tests of association were conducted to explore potential moderators.

RESULTS

A positively skewed distribution was described for the 2 standardized sites. Significant moderators were sex (male higher than female), age (r = 0.22), and self-reported pain intensity (r = -0.24). Neither litigation status nor most symptomatic/least symptomatic side influenced PPT.

CONCLUSIONS

This manuscript presents information regarding the expected scores for PPT testing in people with acute or subacute neck pain. Clinicians can compare the results of individual patients against these population values, and researchers can incorporate the significant confounders of age, sex, and self-reported pain intensity into future research designs.

Cervical facet-mediated pain

The cervical zygapophyseal joints, or facet joints, have long been implicated as a source of neck pain. This article examines the epidemiology of pain arising from these joints and relevant anatomy and histology. An emphasis on clinical findings, examination, and imaging are presented, as well as a focus on whiplash-associated pain.

Interpreting joint pain: quantitative sensory testing in musculoskeletal management

Pain is a common complaint among clients seeking physical therapy services, yet interpretation of associated sensory changes can be difficult for the clinician. Musculoskeletal injury typically results in nociceptive pain due to noxious stimuli of the damaged muscle or joint tissues. However, with progression from acute to chronic stages, altered nociceptive processing can give rise to an array of sensory findings. Specifically, patients with chronic joint injury may present with signs and symptoms typically associated with neuropathic injury, due to changes in nociceptive processing. Clinical presentation may include expansion of hyperalgesia into adjacent and remote areas, allodynia, dysesthesias, and perceptual deficits. Quantitative sensory testing (QST) may provide an objective method of examining sensation and, thereby, of recognizing potential changes in the nociceptive pathways. The purpose of this paper is to provide an overview of altered nociceptive processing and somatosensory changes that may occur following a musculoskeletal injury without associated neural injury. Recommendations are made on clinical uses of quantitative sensory testing in orthopaedic physical therapy practice, and supporting clinical and laboratory evidence are presented. Examples related to joint injury are discussed, specifically, osteoarthritis of the knee and low back pain. Quantitative sensory testing may be a useful clinical tool to aid clinical decision making and for determination of prognosis.

Diagnostic blocks for chronic pain

Many conditions associated with chronic pain have no detectable morphological correlate. Consequently, the source of pain cannot be established by clinical examination or medical imaging. However, for some such conditions, the source of pain can be established using diagnostic blocks. The aim of this paper is to review the available evidence concerning the validity and utility of diagnostic blocks, and to identify areas where research is needed. Diagnostic blocks for cervical and lumbar zygapophysial joint pain have been extensively studied. Single blocks are associated with about 30% false-positive responses. Patients can report relief of pain for reasons other than the effect of a local anaesthetic injected during a diagnostic block, e.g. as the result of placebo effect. Therefore, in order to be valid, diagnostic blocks must be controlled in each patient. Many practitioners find limitations in the clinical applicability of placebo-controlled blocks. Comparative blocks (comparison lidocaine-bupivacaine for each block within each patient) have been investigated as alternatives to placebo-controlled blocks. A positive response requires short-lasting relief when lidocaine is used, and long-lasting relief when bupivacaine is used. The validity of comparative blocks is high when the disease under investigation is common. This is the case for zygapophysial joint pain after whiplash injury. However, the validity of comparative blocks strongly decreases with decreasing prevalence of the condition. This is the case for lumbar zygapophysial joint pain in young subjects: in these patients, the expected false-positive rate with comparative blocks is unacceptably high. Diagnostic blocks for cervical and lumbar zygapophysial joint have therapeutic utility. When positive, radiofrequency denervation is expected to produce substantial pain relief in 60-80% of patients. For all other types of blocks, very little research has been conducted. The few studies that have been published did not use controlled blocks. This may have produced a high rate of false-positive responses. Some data on spinal nerve root blocks suggest that these procedures may be valid for the diagnosis of radicular pain and are perhaps predictive for the success of surgery. The validity of diagnostic sympathetic blocks and their prognostic value in relation to outcomes of sympathectomy are unclear. There is lack of data on the validity of diagnostic intra-articular blocks. Discogenic pain is typically diagnosed by provocative discography, but this procedure remains controversial. Intradiscal and sinuvertebral nerve blocks with local anaesthetics are possible alternatives to provocation discography. At present, the sparse data available on these procedures do not allow an estimation of their validity. In conclusion, nerve blocks have an important potential role in the management of chronic pain. These procedures are not suitable to identify the pathology that is the cause of the pain (e.g. inflammatory, neuropathic, etc.). However, they can reveal the anatomical source of pain, thereby allowing the development of targeted treatments. Unfortunately, there is currently very little research on the validity and prognostic value of blocks. The potential usefulness of this practice remains therefore largely unexplored.