Despite normal neurological bedside and electrodiagnostic, some patients with non-specific neck arm pain (NSNAP) have heightened nerve mechanosensitivity upon neurodynamic testing [1, 2]. It remains however unclear whether this is associated with a minor nerve injury. The aim of this study was to evaluate potential differences in somatosensory function among patients with unilateral NSNAP with and without positive neurodynamic tests and healthy controls.
Quantitative sensory testing was performed in 40 patients with unilateral NSNAP; 23 with positive upper limb neurodynamic tests (ULNTPOS) and 17 with negative neurodynamic tests (ULNTNEG). The protocol comprised thermal and mechanical detection and pain thresholds as well as mechanical pain sensitivity, wind-up ratio and dynamic mechanical allodynia. All parameters were measured in the maximal pain area on the affected side as well as over the corresponding area on the unaffected side. Symptom severity, functional deficits, psychological parameters, quality of life and sleep disturbance were also recorded.
Fifty-seven percent of patients with NSNAP had positive neurodynamic tests despite normal bedside neurological integrity tests and nerve conduction parameters. Clinical profiles did not differ between patient groups. Somatosensory profiling revealed a more pronounced loss of function phenotype in ULNTPOS patients compared to healthy controls. Hyperalgesia (cold, heat and pressure pain) was present bilaterally in both NSNAP group. The ULNTNEG subgroup represented an intermediate phenotype between ULNTPOS patients and healthy controls in both thermal and pressure pain thresholds as well as mechanical detection thresholds.
In conclusion, heightened nerve mechanosensitivity was present in over half of patients with NSNAP. Our data suggest that NSNAP presents as a spectrum with some patients showing signs suggestive of a minor nerve dysfunction.
[1] Elvey RL. Physical evaluation of the peripheral nervous system in disorders of pain and dysfunction. J Hand Ther 1997;10:122-129.
[2] van der Heide B, Bourgoin C, Eils G, Garnevall B, Blackmore M. Test-retest reliability and face validity of a modified neural tissue provocation test in patients with cervicobrachial pain syndrome. J Man Manip Ther 2006;14:30-36.
Relationship of QST measures between low back and leg sites in people with radicular leg pain
(2019)
Background and Aims
Clinicians and researchers often rely on altered neurological integrity tests in the leg to identify radicular pain, however neurological integrity is often not tested in the low back region even in the presence of pain in this region. There have been suggestions that the low back pain itself could be neuropathic in nature in some patients (Baron et al., 2016). This study aims to explore the relationship between quantitative sensory testing (QST) measures in the leg and low back in participants with radicular leg pain to consider if sensory testing should be performed in both areas in clinical practice.
Methods
13 participants (mean age 48.2 SD 13.8, gender (female) 8) with radicular leg pain were recruited from National Health Service spinal clinics in the UK. After assessment with the clinician, a full QST profile was taken from each participant’s affected leg and low back. Z scores were calculated using data from age matched healthy controls. Correlations using Pearson’s if the data was normally distributed or Kendall’s Tau-b if not, were undertaken between QST scores of the low back and leg. Paired t tests or Mann Whitney tests were performed to assess differences in QST scores between the leg and low back regions.
Results
There were no significant correlations (P>0.05) in any of the QST measures between the leg and the low back regions. However, only vibration detection threshold measures showed statistically significant differences between the leg and low back (p<0.001), with the low back region showing greater loss of function (mean -2.84) than the leg (mean -0.61).
Conclusions
Significantly lower vibration thresholds were found in the back compared to the leg. This may suggest some alteration in posterior primary ramus large diameter afferent nerve function, and indicate that the low back pain itself may indeed have a neuropathic component. Our findings suggest that sensory testing of the lumbar spine may be advisable in this group of individuals. The small sample size means that these results must be taken with some caution, however these results warrant further investigation in people with radicular leg pain.
Entrapment neuropathies such as carpal tunnel syndrome, radiculopathies, or radicular pain are the most common peripheral neuropathies and also the most common cause for neuropathic pain. Despite their high prevalence, they often remain challenging to diagnose and manage in a clinical setting. Summarising the evidence from both preclinical and clinical studies, this review provides an update on the aetiology and pathophysiology of entrapment neuropathies. Potential mechanisms are put in perspective with clinical findings. The contemporary assessment is discussed and diagnostic pitfalls highlighted. The evidence for the noninvasive and surgical management of common entrapment neuropathies is summarised and future areas of research are identified.
Entrapment neuropathies are a heterogenous condition reflecting distinct underlying pathomechanisms. A contemporary assessment aimed at identifying potential mechanisms may help target management for these patients.
Nervenkompressionssyndrome („Engpass-Syndrome“) wie Karpaltunnelsyndrom, Radikulopathien oder radikulärer Schmerz sind die häufigsten peripheren Nervenläsionen und auch die häufigste Ursache für neuropathischen Schmerz. Trotz ihrer hohen Prävalenz stellen sie diagnostisch und therapeutisch weiterhin oft eine klinische Herausforderung dar. Die vorliegende Übersicht bietet aktuelle Informationen zur Ätiologie und Pathophysiologie von Nervenkompressionssyndromen; dafür wird die Evidenz aus präklinischen wie auch klinischen Studien zusammengefasst. Mögliche Mechanismen werden in den Kontext klinischer Befunde gestellt. Das aktuelle diagnostische Vorgehen wird erörtert, diagnostische Fallstricke werden beleuchtet. Zuletzt fasst der Beitrag die Evidenz für die nichtinvasive und chirurgische Therapie häufiger Nervenkompressionssyndrome zusammen und zeigt zukünftige Forschungsbereiche auf.
Wir kennen neurodynamische Tests und Behandlungsmethoden, nutzen diese alltäglich in der Praxis und gehen auf Kurse, um mehr darüber zu lernen. Aber was verstehen wir tatsächlich darunter? Kommen wir in unserem Verständnis darüber auf einen gemeinsamen Nenner? Dieser Artikel gibt einen Einblick in die Thematik Neurodynamik. Bisherige Überzeugungen stehen dabei auf dem Prüfstand.
Background:
The evaluation of somatosensory dysfunction is important for diagnostics and may also have implications for prognosis and management. The current standard to evaluate somatosensory dysfunction is quantitative sensory testing (QST), which is expensive and time consuming. This study describes a low-cost and time-efficient clinical sensory test battery (CST), and evaluates its concurrent validity compared to QST.
Method: Three patient cohorts with carpal tunnel syndrome (CTS, n=86), non-specific neck and arm pain (NSNAP, n=40) and lumbar radicular pain/radiculopathy (LR n=26) were included. The CST consisted of 13 tests, each corresponding to a QST parameter and evaluating a broad spectrum of sensory functions using mechanical and thermal detection and pain thresholds and testing both loss and gain of function. Agreement rate, significance and strength of correlation between CST and QST were calculated.
Results: Several CST parameters (cold and warm detection, cold pain, mechanical detection, mechanical pain for loss of function, pressure pain) were significantly correlated with QST, with a majority demonstrating >60% agreement rates and weak to relatively strong correlations. However, agreement varied among cohorts. Gain of function parameters showed stronger correlation in the CTS and NSNAP cohort, whereas loss of function parameters performed better in the LR cohort. Other CST parameters (vibration detection, heat pain, mechanical pain for gain of function, windup ratio) did not significantly correlate with QST.
Conclusion: Some, but not all tests in the CST battery can detect somatosensory dysfunction as determined with QST. The CST battery may perform better when the somatosensory phenotype is more pronounced.
Background
This study describes a low-cost and time-efficient clinical sensory test (CST) battery and evaluates its concurrent validity as a screening tool to detect somatosensory dysfunction as determined using quantitative sensory testing (QST).
Method
Three patient cohorts with carpal tunnel syndrome (CTS, n = 76), non-specific neck and arm pain (NSNAP, n = 40) and lumbar radicular pain/radiculopathy (LR, n = 26) were included. The CST consisted of 13 tests, each corresponding to a QST parameter and evaluating a broad spectrum of sensory functions using thermal (coins, ice cube, hot test tube) and mechanical (cotton wool, von Frey hairs, tuning fork, toothpicks, thumb and eraser pressure) detection and pain thresholds testing both loss and gain of function. Agreement rate, statistical significance and strength of correlation (phi coefficient) between CST and QST parameters were calculated.
Results
Several CST parameters (cold, warm and mechanical detection thresholds as well as cold and pressure pain thresholds) were significantly correlated with QST, with a majority demonstrating >60% agreement rates and moderate to relatively strong correlations. However, agreement varied among cohorts. Gain of function parameters showed stronger agreement in the CTS and LR cohorts, whereas loss of function parameters had better agreement in the NSNAP cohort. Other CST parameters (16 mN von Frey tests, vibration detection, heat and mechanical pain thresholds, wind-up ratio) did not significantly correlate with QST.
Conclusion
Some of the tests in the CST could help detect somatosensory dysfunction as determined with QST. Parts of the CST could therefore be used as a low-cost screening tool in a clinical setting.
Significance
Quantitative sensory testing, albeit considered the gold standard to evaluate somatosensory dysfunction, requires expensive equipment, specialized examiner training and substantial time commitment which challenges its use in a clinical setting. Our study describes a CST as a low-cost and time-efficient alternative. Some of the CST tools (cold, warm, mechanical detection thresholds; pressure pain thresholds) significantly correlated with the respective QST parameters, suggesting that they may be useful in a clinical setting to detect sensory dysfunction.
Entrapment neuropathies are the most prevalent type of peripheral neuropathy and often a challenge to diagnose and treat. To a large extent, our current knowledge is based on empirical concepts and early (often biomechanical) studies. This Viewpoint will challenge some of the current beliefs with recent advances in both basic and clinical neurosciences.