Marzia Stella Yousif [Faculty of Medicine and Surgery, Department of Clinical Sciences and Translation Medicine, University of Rome Tor Vergata, Rome, Italy]
Giuseppe Occhipinti [Freelance Physiotherapist at H.T. Clinic, Ragusa, Italy]
Filippo Bianchini [Istituti Clinici Scientifici Maugeri IRCCS, Occupational Therapy and Ergonomics Unit, Montescano, 27040, Italy]
Daniel Feller [Provincial Agency for Health of the Autonomous Province of Trento, Trento, Italy; Centre of Higher Education for Health Sciences of Trento, Trento, Italy]
Annina Schmid [Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, OX39DU, UK]
Firas Mourad [Department of Physiotherapy, LUNEX International University of Health, Exercise and Sports, 4671 Differdange, Luxembourg; Luxembourg Health & Sport Sciences Research Institute A.s.b.l., 50, Avenue du Parc des Sports, 4671 Differdange, Luxembourg]
Peripheral nerve compression and/or irritation within narrow anatomical spaces are known as entrapment neuropathies. Although aetiology remains largely unknown, cervical radiculopathy (CR) is one entrapment neuropathy CR prevalence variability (from 1.07 to 1.76 per 1,000 and 0.63 to 5.8 per 1,000 for males and females, respectively) is likely attributable to the differing diagnostic criteria, the geographical population location, and occupational features. Our understanding of CR is still limited and based on early studies, reporting a heterogeneity of pathomechanisms and various clinical presentations. Indeed, the definition of CR is not universally accepted among guidelines which commonly define CR by symptoms (e.g., pain or paraesthesia) radiating into the arm. However, according to the IASP definition, radiculopathies are not defined by pain/symptoms, but by action potential conduction slowing or block of a spinal nerve or its roots, leading to loss of sensory and/or motor function. Pain and paraesthesia are indicative of gain of nerve function while neurological deficit is indicative of loss of nerve function and therefore a core sign of CR. This clinically manifests as dermatomal sensory loss, myotomal weakness, and/or deep tendon reflex (DTR) changes.
Traditionally, clinicians and researchers diagnose CR performing a physical examination which include, neural mechanosensitive testing (e.g., upper limb neurodynamic tests) and provocative neck manoeuvres (e.g., spurling test). However, these commonly used have limited clinical use in identifying loss of nerve function but are designed to detect predominantly gain of nerve function. Diagnostic imaging (e.g., Magnetic Resonance Imaging (MRI)) and, neurophysiological testing (e.g., electromyography (EMG)) , were also suggested to optimize diagnostic accuracy. However, their clinical significance of findings remains contentious due to the high frequency of false positive and false negative results.
Among the clinical tests routinely used to identify loss of nerve function, the bedside neurological examination (BNE) (i.e., sensory loss (light touch, pinprick, cold/worm), myotomal weakness, reduced DTR) for the assessment of peripheral sensory and motor responses has historically played a role in the differential diagnosis and in the prognostic profile of radiculopathy. Therefore, to diagnose CR in line with the IASP definition, signs of neurological deficits have to be examined with the BNE. However, it is unclear what is the evidence about the diagnostic accuracy of the BNE in diagnosing CR: one recent review didn’t find studies while other studies reported little literature. Also, no standardised guidance exists about the component and performance of the BNE for CR. This may lead to an increased risk of misdiagnosis and inappropriate treatment, resulting in delayed recovery and poor health outcomes. For these reasons, a scoping review was conducted to systematically map the research done in this area, to identify any existing gaps in knowledge, and to inform future studies. The following research questions was formulated: What is known from the literature about the diagnostic criteria, components, and performance of the BNE in diagnosing CR?
Our scoping review was performed following the 6-stage methodology suggested by Arksey and O’Malley. It was conducted following the extensions to the original framework recommended by the Joanna Briggs Institute methodology (JBI) for scoping reviews. The PRISMA extension for Scoping Reviews Checklist was used for reporting .
Eligibility criteria
We followed the framework of Population, Concept and Context (PCC):
Search strategy
The research group developed a three-step approach.
The PRISMA literature search extension was used to report the search strategies.
Study selection and data extraction/synthesis
Titles and abstracts to identify potentially eligible records were screened. Endnote (Clarivate Analytics, PA, USA) was used to remove duplicates. If a full-text could not be retrieved, we contacted authors with a maximum of two attempts on a weekly basis. Subsequently, full-texts were assessed for eligibility; any reasons for exclusions were recorded. We used the Rayyan platform for the selection process.
Data extraction was conducted using an ad‐hoc data extraction form which was developed a priori, based on the JBI data extraction tool. A third researcher resolved unreconciled disputes. Extracted information included author(s), year of publication, study location, study population and size, aims of the study, study design, reference test to diagnose CR, details of the BNE including information on its performance, diagnostic accuracy, and relevant results and considerations. Any modifications to the data extraction strategy were reported in the results section. When diagnostic accuracy values were missing, we calculated them based on true positives, false positives, true negatives, and false negatives when reported. In case likelihood ratios (LR) were not provided, we calculated them using the sensitivity and specificity values when reported. Records selection and data extraction process were performed independently by 2 blinded reviewers. Discrepancies were discussed with another reviewer
Descriptive analyses were performed, and the results were presented numerically. Included studies were reported as frequency and percentage. In addition, extracted data were summarized in tables. The performance and components of the BNE were reported qualitatively. Diagnostic accuracy were reported by sensitivity/specificity and +/- LRs according to the reference standard. Index test and nerve root were detailed when available. Missing data was gathered by contacting the corresponding author with a maximum of two attempts on a weekly basis.
The initial literature search yielded 11,516 records, with 11,512 from the database and 4 from citation searching. After preliminary screening and duplicate removal, 11,456 records were excluded. Of the remaining 60 records, 6 could not be retrieved, and 46 were excluded after full-text review due to not meeting inclusion criteria, providing redundant information, or lacking sufficient details on NE diagnostic accuracy and procedures. Four more articles were excluded because the authors did not respond to requests for additional data.
A second literature search identified 592 new articles, with 590 excluded after preliminary screening and duplicate removal. The remaining two articles were excluded after full-text review for not meeting inclusion criteria.
Ultimately, 6 articles were included based on the inclusion criteria outlined in the PRISMA 2020 flow diagram. These articles are summarized in Table 2. All included studies were cross-sectional and in English, representing five countries, with the United States having the highest representation (n=2; 33%). Three studies (50%) were published between 2000-2010, two (33%) between 2011-2020, and one (17%) in 2021. One study (17%) was conducted in a primary care setting, two (33%) in a secondary care setting, and three (50%) in tertiary care settings.
Examiners and NE Reporting
Participants with cervical radiculopathy (CR) were recruited based on clinical suspicion in 4 studies (67%) and a diagnosis by a consultant using MRI and electromyography (EMG) in 2 studies (33%). NE was performed by physicians without reported specialties in 2 studies (33%), EMG specialists in 1 study (17%), and physiotherapists in 3 studies (50%).
The reporting of NE procedures was generally poor and vague. Four studies (67%) did not report the procedures or any references to the NE used. One study conducted a bedside neurologic examination according to Butler (2000). Only one study described the NE procedure in detail, using the 3 components of NE (somatosensation, muscle function, and deep tendon reflexes).
Diagnostic Accuracy
The reference tests for diagnosing CR were heterogeneous. Most studies investigated the diagnostic accuracy of NE compared to electrodiagnostic tests (EDX) or MRI. Only three studies assessed the diagnostic accuracy of the entire bedside neurologic examination. One study reported sensitivity values alone.
Somatosensation
Somatosensation was typically assessed using soft brushes, soft balls, and pinpricks, following dermatomal maps. Sensitivity values ranged between 12% and 38%, with specificity values between 66% and 89%. The specificity was generally higher when compared with EDX than MRI, reflecting higher false positive rates with MRI.
Reflexes
Reduced deep tendon reflexes showed high specificity (93%-99%) but low sensitivity (3%-22%) when compared to EDX. The lowest specificity was found in studies comparing NE with MRI, showing a high sensitivity (up to 66.7%).
Muscle Function
Muscle weakness testing had sensitivity values ranging from 3% to 73%, and specificity values between 61% to 94% when compared to EMG. One study reported detailed diagnostic accuracy values for each muscle tested.
Combined Testing
Studies examining combined NE components found low sensitivity (9%-27%) but high specificity (74%-99%) for combinations of two components. Combining all three components resulted in high specificity (98%-99%) but low sensitivity (7%-14%).
Summary
Overall, the clinical presentation of acute CR is variable, with multiple-level distribution patterns of motor weakness, sensory changes, and diminished deep tendon reflexes. Motor changes were the most effective in detecting the damaged root, with sensory and reflex changes being less effective. The NE’s efficacy in predicting EDX test results was limited, with no significant relationship between NE and EDX outcomes. NE should guide EMG decisions, but a normal NE should not prejudice electrodiagnostic testing.
The primary challenge in diagnosing cervical radiculopathy (CR) is the absence of universally accepted definitions and diagnostic criteria. Many guidelines define CR as spine-related arm pain, which complicates clarity on the topic. This, coupled with limited research on conservative management, affects the effectiveness and replicability of care. The Neuropathic Pain Special Interest Group of the International Association for the Study of Pain has recommended specific terminology and identification criteria for neuropathic pain, emphasizing that neurological deficits are core clinical signs of radiculopathy. However, our review found a scarcity of studies evaluating the diagnostic performance of the neurological examination (NE) for CR, partly due to the lack of a reliable gold standard for comparison.
Most studies in our review used diagnostic imaging or electrodiagnostic tests (EDX) as reference standards. Routine imaging has a 30% false negative and false positive rate in detecting nerve root compromise when radiculopathy is suspected. Additionally, the patient’s position during imaging can influence the degree of nerve root compression observed, affecting interpretation. EDX examines only large myelinated fibers, representing about 20% of a peripheral nerve, and cannot detect small fiber damage. In our review, MRI showed higher sensitivity while EMG showed higher specificity compared to NE in identifying the relevant nerve root.
Loss of function signs, such as dermatomal hypoesthesia, myotomal weakness, and reduced reflexes, are critical for diagnosing CR. When CR is suspected, NE is used to identify loss of action potential conductivity. Standard NE includes examining muscle function, deep tendon reflexes, and somatosensation of both large (light touch) and small (cold/warm and pin-prick) fibers. However, evidence on how to perform a valid and reliable NE is lacking. Our review found that descriptions of NE were often vague and poor in the included studies. Consistent assessments of key muscles, deep tendon reflexes, and key sensory points were used to determine nerve root compromise. Only one study included small fiber testing.
Most included studies used spine-related arm pain as a diagnostic criterion for CR. However, radiculopathy should be defined by loss of function signs, not pain type, as it can occur with or without radicular pain. Radicular pain often has neuropathic characteristics (e.g., electric shocks, shooting pain, tingling, pins and needles), but a lack of history indicating a neural lesion does not meet the criteria for peripheral neuropathic pain and does not exclude somatic-referred pain. This inconsistency reflects the lack of a firm definition and diagnostic criteria for CR in guidelines.
NE is crucial for diagnosing radiculopathy and influencing its management, yet few studies assess the diagnostic accuracy of NE for CR. MRI, commonly used as a reference diagnostic tool, has several limitations, including high false positive and negative rates and positional dependence. Our review found muscle weakness and reduced reflexes to be the most specific and sensitive indicators for CR, respectively, with their combination increasing the likelihood of CR ninefold. The association of heightened nerve mechanosensitivity, radicular pain, and numbness was found to have 99% specificity.
Similarly, there is a paucity of studies on the diagnostic accuracy of NE for lumbar radiculopathy (LR), with similar limitations in reference standard testing (MRI, EDX, or intra-operative tests). Our results on NE’s diagnostic performance for CR align with those found for LR. A recent systematic review by Tawa et al. reported sensitivity of 0.61 and specificity of 0.63 for sensory testing, sensitivity ranging from 0.13 to 0.61 for muscle function testing, and reflex testing showing the highest specificity (0.60 to 0.93) and variable sensitivity (0.14 to 0.67). These results should be interpreted cautiously due to factors like verification bias and the lack of a gold standard in primary diagnostic accuracy studies.
Diagnostic imaging accurately detects visually structural nerve root lesions but does not necessarily reflect loss of function signs. Variability among published dermatomal maps, due to significant overlap and individual variations, also affects sensory testing interpretation.
A proposed grading system for neuropathic pain involves verifying criteria, including diagnostic tests confirming somatosensory nervous system lesions. This system, following routine patient consultation steps, may enhance CR diagnosis by increasing specificity and confidence.
The validity of diagnostic tests like CT and MRI has been criticized due to high false positive and negative rates. Our review suggests diagnostic tests should follow specific criteria. EMG is useful for identifying the involved level when clear sensory loss signs are present, especially muscle weakness in single-level radiculopathies (C5, C7, or C8). However, EMG does not examine small fiber function. MRI and CT can be used when clinical signs are uncertain, but findings may not correlate with pathology.
Future research should focus on the potential role of clinical neurological examination as a diagnostic reference standard. Standardizing NE procedures should be prioritized to enable its use as a screening tool and reliable outcome measure. Additionally, investigating signs and symptoms indicating gain of function and their association with NE findings in diagnosing cervical radiculopathy is necessary.
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