Electrodiagnostic Evaluation Research Articles

Canine models of Charcot-Marie-Tooth: MTMR2, MPZ, and SH3TC2 variants in golden retrievers with congenital hypomyelinating polyneuropathy

Congenital hypomyelinating polyneuropathy (HPN) restricted to the peripheral nervous system was reported in 1989 in two Golden Retriever (GR) littermates. Recently, four additional cases of congenital HPN in young, unrelated GRs were diagnosed via neurological examination, electrodiagnostic evaluation, and peripheral nerve pathology. Whole-genome sequencing was performed on all four GRs, and variants from each dog were compared to variants found across >1,000 other dogs, all presumably unaffected with HPN. Likely causative variants were identified for each HPN-affected GR. Two cases shared a homozygous splice donor site variant in MTMR2, with a stop codon introduced within six codons following the inclusion of the intron. One case had a heterozygous MPZ isoleucine to threonine substitution. The last case had a homozygous SH3TC2 nonsense variant predicted to truncate approximately one-half of the protein. Haplotype analysis using 524 GR established the novelty of the identified variants. Each variant occurs within genes that are associated with the human Charcot-Marie-Tooth (CMT) group of heterogeneous diseases, affecting the peripheral nervous system. Testing a large GR population (n = >200) did not identify any dogs with these variants. Although these variants are rare within the general GR population, breeders should be cautious to avoid propagating these alleles.

COLQ-related congenital myasthenic syndrome: An integrative view.

Congenital myasthenic syndromes are inherited disorders caused by mutation in components of the neuromuscular junction and manifest early in life. Mutations in COLQ gene result in congenital myasthenic syndrome. Here, we present the analysis of data from 209 patients from 195 unrelated families highlighting genotype-phenotype correlation. In addition, we describe a COLQ homozygous variant a new patient and discuss it utilizing the Phyre2 and I-TASSER programs. Clinical, molecular genetics, imaging (MRI), and electrodiagnostic (EEG, EMG/NCS) evaluations were performed. Our data showed 89 pathogenic/likely pathogenic variants including 35 missenses, 21 indels, 14 nonsense, 14 splicing, and 5 large deletions variants. Eight common variants were responsible for 48.46% of those. Weakness in proximal muscles, hypotonia, and generalized weakness were detected in all individuals tested. Apart from the weakness, extensive clinical heterogeneity was noted among patients with COLQ-related patients based on their genotypes-those with variants affecting the splice site exhibited more severe clinical features while those with missense variants displayed milder phenotypes, suggesting the role of differential splice variants in multiple functions within the muscle. Analyses and descriptions of these COLQ variants may be helpful in clinical trial readiness and potential development of novel therapies in the setting of established structure-function relationships.

Electrodiagnostic Evaluation of Prognostic Factors Influencing the Surgical Outcomes of Upper Extremity Nerve Injuries Caused by Penetrating Trauma: A Cross-sectional Study

Electrodiagnostic Evaluation of Prognostic Factors Influencing the Surgical Outcomes of Upper Extremity Nerve Injuries Caused by Penetrating Trauma: A Cross-sectional Study

Serum Neurofilament Light Chain Levels in Small Fiber Neuropathy Patients with Skin Denervation and Ongoing Neuropathic Symptoms (P14-8.004)

<h3>Objective:</h3> To identify active axonal damage by measurement of serum neurofilament light chain (sNfL) levels in patients with small fiber neuropathy (SFN) and ongoing neuropathy symptoms. <h3>Background:</h3> SFN is associated with sensory symptoms and is evident by skin biopsy which show a reduction of the intraepidermal nerve fiber density (IENFD) indicating skin denervation. SFN patients may complain of prolonged/worsening symptoms, but it is not clear if this is associated with continuous axonal damage. <h3>Design/Methods:</h3> Blood samples were collected from 95 consecutive patients that were referred for a skin biopsy due to suspected SFN. All patients had symptoms that were consistent with a clinical diagnosis of SFN. Patients were excluded if they had clinical or imaging evidence for a central nervous system disorder, electrodiagnostic abnormalities or absence of electrodiagnostic evaluation. Following these exclusions, 34 patients were included for analysis. Skin biopsy was performed 2–3 months from symptoms onset by 4 patients, 4–12 months by 7, and after more than 12 months by 23. Severe skin denervation was defined by an intraepidermal nerve fiber density (IENFD) below the 5^th percentile per age, mild denervation when the IENFD was at the 5–20^th percentiles, and above the 20^th percentile was considered normal. <h3>Results:</h3> The majority of patients (29/34; 85%) showed normal sNfL levels and almost half of the patients showed skin denervation (15/34; 44%). Two patients with skin denervation (2/15; 13.3%) showed elevated sNfL, after 7 and more than 12 months from symptoms onset. The skin biopsy was normal in the other 3 patients with elevated sNfL, obtained 2, 8 and more than 12 months from symptoms onset. All patients with elevated sNfL had a history of chemotherapy treatment or immune-mediated disorders. <h3>Conclusions:</h3> In this cohort, a small portion of patients with SFN and skin denervation showed increased sNfL which indicated ongoing axonal damage. <b>Disclosure:</b> Dr. Zohar has nothing to disclose. Miss Qassim has nothing to disclose. Dr. Eltity has nothing to disclose. Dr. Keren has nothing to disclose. Efrat Shavit has nothing to disclose. Dr. Chapman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Mapi Pharma. Dr. Chapman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi Genzyme. Dr. Chapman has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Merk Serono. The institution of Dr. Chapman has received research support from Ministry Of Industry. Dr. Dori has received personal compensation in the range of $500-$4,999 for serving as a Consultant for TEVA. Dr. Dori has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Takeda . Dr. Dori has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Sanofi. Dr. Dori has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Medison Pharma. Dr. Dori has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Medison Pharma. The institution of Dr. Dori has received research support from Biogen. The institution of Dr. Dori has received research support from Pfizer. The institution of Dr. Dori has received research support from Alnylam therapeutics. Dr. Dori has received intellectual property interests from a discovery or technology relating to health care.

Isolated medial antebrachial cutaneous nerve injury after blunt trauma: a case report

BackgroundThe medial antebrachial cutaneous nerve is a branch of the brachial plexus that contains C8–T1 segments. Injury of this nerve by various mechanisms has been reported in the literature; however, currently, there is no reported case of medial antebrachial cutaneous nerve injury in the setting of acute blunt trauma.Case presentationThis case report presents the case of a 34-year-old Persian female with dysesthesia and pain in the medial side of the forearm immediately following a blunt trauma by mechanism of elbow external rotation. On electrodiagnostic evaluation, the medial antebrachial cutaneous nerve sensory nerve action potential of the symptomatic side had a significant amplitude drop (more than 50%), compared with the other side. On follow-up electrodiagnosis, after several sessions of physical therapy, the medial antebrachial cutaneous nerve sensory nerve action potential still had a significant amplitude difference.ConclusionBlunt trauma can be one of the causes of medial antebrachial cutaneous nerve involvement. An electrodiagnostic study can be helpful in the diagnosis of this nerve injury after blunt trauma.

Clinical spectrum, risk factors and electrophysiologic aspect of radial nerve injury

Background and objective: &#x0D; Radial nerve is injured due to a variety of reasons. The objective of this study was to determine the clinical spectrum, risk factors and electrophysiologic aspect of radial nerve injury presenting to a tertiary care hospital in Lahore.&#x0D; Methods: &#x0D; This descriptive prospective cross-sectional study was conducted at department of Neurology, Mayo hospital Lahore from July 2022 to December 2022 and comprised patients with isolated radial nerve injury on the basis of history and clinical examination regardless of their gender, above 15 years of age. NCS/EMG was done on a Japanese machine Nihon Kohden by an expert as per recommended protocol for electrodiagnostic evaluation of a suspected radial nerve injury and interpreted by consultant neurologist.&#x0D; Results: &#x0D; Of 75 patients, 52(69.3%) were males and 23(30.7%) were females. The most common etiology turned out to be misplaced intramuscular injection in 45(60%) of the patients. The site of lesion in most cases was in the spiral groove in 36 (40%) of the patient. Most of the patients i.e. 71(94.7%) had a wrist drop. Evidence of reinnervation was present in 30(40%) of patients.&#x0D; Conclusion: &#x0D; Most cases of radial nerve injury presented with a wrist drop in which the commonest etiology was misplaced intramuscular injection. The site of lesion in most cases turned out to at the level of spiral groove, and the nature of lesion was primarily axonal loss followed by secondary demyelination.

Sural nerve conduction: Amplitude and distal latency of sensory nerve action potential

Background: The sensory nerve action potential (SNAP) is an important factor in the electro diagnostic evaluation of a patient with suspected peripheral neuropathy. Sural nerve is the most frequently studied nerve in the electrophysiology. For proper diagnosis sural sensory conduction abnormalities, a reference data are required for each electrophysiology laboratory. Aims and Objectives: The aim of the study was to find out normative reference data of amplitude and distal latency (DL) of sural SNAP for Northern Kerala population. Materials and Methods: The study was designed as cross-sectional and observational study and analysis of values was done using SPSS version 16. A total of 250 healthy subjects of age 15–50 from Northern Kerala participated in the study which included equal number of males and females. Results: Normative reference data for sensory amplitude and DL were derived in the present study. Sensory amplitude was more and DL was found to be less in female population, indicating faster nerve conduction in female. Conclusion: The reference data derived here can be utilized to detect any abnormality sural nerve sensory conduction. The gender effect on sural nerve sensory conduction parameters can be attributed to the height difference, as nerve conduction velocity is inversely proportional to height.

Electrodiagnostic Study of the Patients with Suspected Carpal Tunnel Syndrome

Various electrodiagnostic tests are employed for diagnosis of carpal tunnel syndrome reporting wide range of sensitivity and specificity for each test in clinical practice. Therefore, the aim of our study is to assess the sensitivity of electrodiagnostic tests used in our set up for the diagnosis of carpal tunnel syndrome. This cross-sectional study consisted of 21 patients suspected with carpal tunnel syndrome who were referred to neurophysiology lab for electrodiagnostic evaluation and 21 age-group gender matched healthy controls. Digit 4, lumbrical versus ulnar interossei latencies and conventional nerve conduction variables were recorded. A p value of less than 0.05 was considered significant. The sensitivity of median versus ulnar digit 4 sensory latency difference was the highest (72.72 %) whereas the conduction velocity of median nerve was the lowest (45.45%). The lumbrical versus ulnar interossei latency difference was significant between groups; however the sensitivity was only 51.52%. The conduction velocity of median nerve was relatively slower in the suspected cases than controls (49.67±13.75 vs. 60.90 ±6.70; p=0.007). The distal sensory latency of median nerve was significant between groups (3.47 ±0.58 vs. 2.16±0.25; p=0.03). The distal and proximal latencies of motor median nerve were significant between suspected cases and controls (4.70±1.82 vs. 2.75±0.38; p=<0.001). The sensitivity of median versus ulnar digit 4 sensory latency difference was the highest in our set up therefore, addition of this test with conventional method can be helpful in achieving a higher diagnosis rate.

WE-161. Concentric Macro-EMG role in electrodiagnostic evaluation of inflammatory myopathies.

WE-161. Concentric Macro-EMG role in electrodiagnostic evaluation of inflammatory myopathies.

Clinical electrodiagnostic evaluation for nerve transfer surgery in spinal cord injury: a new indication and clinical pearls.

In this review, we highlight the important role of the clinical electrodiagnostic (EDX) evaluation after cervical spinal cord injury (SCI). Our discussion focuses on the need for timely, frequent, and accurate EDX evaluations in the context of nerve transfer surgery to restore critical upper limb functions, including elbow extension, hand opening, and hand closing. The EDX evaluation is crucial to define the extent of lower motor neuron lesions and determine candidacy for surgery. We also discuss the important role of the postoperative EDX evaluation in determining prognosis and supporting rehabilitation. We propose a practical framework for EDX evaluation in this clinical setting.

Preoperative electrodiagnostic planning for upper limb peripheral nerve transfers in cervical spinal cord injury: A narrative review.

Peripheral nerve transfer (PNT) to improve upper limb function following cervical spinal cord injury (SCI) involves the transfer of supralesional donor nerves under voluntary control to intralesional or sublesional lower motor neurons not under voluntary control. Appropriate selection of donor and recipient nerves and surgical timing affect functional outcomes. Although the gold standard of nerve selection is intraoperative nerve stimulation, preoperative electrodiagnostic (EDX) evaluation may help guide surgical planning. Currently there is no standardized preoperative EDX protocol. This study reviews the EDX workup preceding PNT surgery in cervical SCI and proposes an informed EDX protocol to assist with surgical planning. The PICO (Population, Intervention, Comparison, Outcome) framework was used to formulate relevant Medical Subject Headings (MeSH) terms and identify published cases of PNT in cervical SCI in Medline, Embase, CINAHL, and Emcare databases in the last 10 years. The EDX techniques evaluating putative donor nerves, recipient nerve branches, time sensitivity of nerve transfer and other electrophysiological parameters were summarized to guide creation of a preoperative EDX protocol. Needle electromyography (EMG) was the most commonly used EDX technique to identify healthy donor nerves. Although needle EMG has also been used on recipient nerves, compound muscle action potential amplitudes may provide a more accurate determination of recipient nerve health and time sensitivity for nerve transfer. Although there has been progress in presurgical EDX evaluation, EMG and nerve conduction study approaches are variable, and each has limitations in their utility for preoperative planning. There is need for standardization in the EDX evaluation preceding PNT surgery to assist with donor and recipient nerve selection, surgical timing and to optimize outcomes. Based on results of this review, herein we propose the PreSCIse (PRotocol for Electrodiagnosis in SCI Surgery of the upper Extremity) preoperative EDX panel to achieve said goals through an interdisciplinary and patient-centered approach.

Nerve high-resolution ultrasound in a 2-year follow-up of radial nerve palsy related to humeral shaft fractures.

High-resolution nerve ultrasonography (HRUS) could have an emerging importance in diagnosis and follow-up of axonopathic radial palsy associated with humeral shaft fractures due to closed trauma. The aim of our study was to establish the role of HURS in this context through a longitudinal multimodal analysis. Clinical, electrodiagnostic (EDX) and HRUS evaluations were prospectively performed at month 1, 3, 6, 12 and 24 from injury, in a continuous series of 19 patients collected in a 5-year study. Clinical severity was scored on MRC of involved muscles, EDX on presence/absence of functional continuity; anatomical continuity and nerve cross sectional area (NCSA) of radial (RN) and posterior interosseus (PIN) nerves were evaluated through HRUS. All patients showed clinical improvement during follow-up; EDX functional continuity was reached by all patients within 12 months; HRUS revealed RN anatomical continuity in all patients and PIN involvement in 74%. RN NCSA progressively reduced during FU, but it was still significantly higher than contralateral at month 24; PIN NCSA became normal within 24 months. When anatomical RN continuity is confirmed by HRUS, good functional outcome is reached even in patients with EDX loss of functional continuity. Together with clinical and EDX evaluations, HRUS may provide useful data in the follow-up of radial palsy due to humeral shaft fractures.

Electrodiagnostic evaluation in differential diagnosis and neurosurgical treatment of radiculopathies caused by spine disorders. Diagnostic value and methodology

To assess the role of electromyography including paraspinal muscle mapping in diagnosis of radiculopathies following spine diseases. We have analyzed literature data in the Scopus, Pubmed, and RSCI databases and selected 93 references for primary reviewing. Final analysis enrolled the manuscripts with a detailed description of neurophysiological examinations and data on sensitivity/specificity of these methods. Needle electromyography (EMG) is the most informative neurophysiological method for diagnosis of radicular damage. Sensitivity of EMG is up to 90% for lumbosacral radiculopathy. Electromyography of the paraspinal muscles can be used in case of of cervical, thoracic and lumbar radiculopathy in addition to EMG of limb muscles. Therefore sensitivity increases to 100%. Diagnostic value of nerve conduction study (NCS) is low, and performing NCS without EMG is not useful. In neurosurgical practice electrodiagnostic (EDX) should be performed for differential diagnosis of radiculopathy and peripheral nervous system lesions, to determine the level of radicular compression, and when physical examination does not correspond with neuroimaging or MRI is not possible to perform.

Focal Peripheral Neuropathies Observed in Patients Diagnosed With COVID-19: A Case Series.

A growing number of studies have documented a wide variety of neurological manifestations associated with the novel SARS-CoV-2 (COVID-19). Of the available literature, cranial neuropathies and central nervous system disorders, such as encephalopathy and ischemic strokes, remain the predominant discussion. Limited investigations exist examining peripheral neuropathies of those with COVID-19. This case series discusses eight patients who tested positive for COVID-19 and presented with localized weakness after a prolonged course of mechanical ventilation (>21 days). We retrospectively reviewed all patients' charts who received electrodiagnostic evaluation between March and November 2020 in the outpatient clinic or in the acute care hospital at the JFK Medical Center/JFK Johnson Rehabilitation Institute and Saint Peter's University Hospital of New Jersey. A total of eight COVID-19-positive patients were identified to have a clinical presentation of localized weakness after a prolonged course of mechanical ventilation. All patients were subsequently found to have a focal peripheral neuropathy of varying severity that was confirmed by electrodiagnostic testing. Patient demographics, clinical, and electrodiagnostic findings were documented. The findings of local weakness and focal peripheral neuropathies after diagnosis of COVID-19 raise significant questions regarding underlying pathophysiology and overall prognosis associated with COVID-19.

Hereditary sensory and autonomic neuropathy in a family of mixed breed dogs associated with a novel RETREG1 variant.

BackgroundHereditary sensory and autonomic neuropathies (HSANs) are a group of genetic disorders affecting the peripheral nervous system. Two different associated variants have been identified in dogs: 1 in Border Collies and 1 in Spaniels and Pointers.ObjectivesClinically and genetically characterize HSAN in a family of mixed breed dogs.AnimalsFive 7‐month‐old mixed breed dogs from 2 related litters were presented for evaluation of a 2‐month history of acral mutilation and progressive pelvic limb gait abnormalities.MethodsComplete physical, neurological, electrodiagnostic, and histopathological evaluations were performed. Whole genome sequencing of 2 affected dogs (1 from each litter) was used to identify variants that were homozygous or heterozygous in both cases, but wild type in 217 control genomes of 100 breeds. Immunohistochemistry was used to assess protein expression.ResultsComplete physical, neurological, electrodiagnostic, and histopathological evaluations confirmed a disorder affecting sensory and autonomic nerves. Whole genome sequencing identified a missense variant in the RETREG1 (reticulophagy regulator 1) gene (c.656C > T, p.P219L). All affected dogs were homozygous for the variant, which was not detected in 1193 dogs from different breeds. Immunohistochemistry showed no expression of RETREG1 in the cerebellum of affected dogs. One of the affected dogs lived for 5 years and showed gradual progression of the clinical signs.Conclusions and Clinical ImportanceWe confirmed the diagnosis of HSAN in a family of mixed breed dogs and identified a novel and possibly pathogenic RETREG1 variant. Affected dogs experienced gradual deterioration over several years.

Review Article "Spotlight on Ultrasonography in the Diagnosis of Peripheral Nerve Disease: The Evidence to Date".

Neuromuscular ultrasound is rapidly becoming incorporated into clinical practice as a standard tool in the assessment of peripheral nerve diseases. Ultrasound complements clinical phenotyping and electrodiagnostic evaluation, providing critical structural anatomical information to enhance diagnosis and identify structural pathology. This review article examines the evidence supporting neuromuscular ultrasound in the diagnosis of compressive mononeuropathies, traumatic nerve injury, generalised peripheral neuropathy and motor neuron disease. Extending the sonographic evaluation of nerves beyond simple morphological measurements has the potential to improve diagnostics in peripheral neuropathy, as well as advancing the understanding of pathological mechanisms, which in turn will promote precise therapies and improve therapeutic outcomes.

WS3.2. Electrophysiological Assessment of Brachial Plexopathies

The brachial plexus has more than 166,000 interconnected axons and it́s a very vulnerable structure. Imaging studies do not provide functional information about the plexus and routine electrodiagnostic studies are usually incomplete. The anatomy and pathophysiology of the lesions must be known to improve the treatment outcomes. The clinical and electrodiagnostic evaluations must be extensive but oriented. A root injury must be suspected after traction injuries, proximal wounds, in the presence of impairment of muscles innervated directly from roots like anterior serratus, rhomboids, diaphragm and in the presence of dysfunction of sympathetic preganglionic fibers from C8-T1. A trunk injury must be suspected after supraclavicular or retro-clavicular injuries, in the presence of suprascapular nerve involvement (upper trunk) or selective impairment of median or radial nerves. No branches arise from middle or lower trunks and isolated middle trunk lesions are very rare. An injury at the cord level must be suspected after infra-clavicular injuries, in presence of involvement of the medial brachial and antebrachial cutaneous nerves, involvement of latissimus dorsi, pectoralis and median nerve selective compromise. In motor nerve conduction studies (MNCS), the distal amplitude represents an estimate of the number of viable axons. For uncommon MNCS the side to side amplitude comparison is the best indicator of nerve damage. No motor NCS is available for C7. Some MNCS are helpful to localize (e.g.: radial over EIP, suprascapular). The sensory nerve conduction studies (SNCS) are helpful to differentiate a pre vs postganglionic lesion (after > 10 days). Detailed sensory studies help to define injured structures even better than motor conductions. No sensory NCS is available for C5. The needle EMG studies are useful to detect mild axonal loss. There is no correlation between number of Fibs/PSWs and severity of the axonal loss. The recruitment reduced in conduction block. Localizing muscles must be evaluated and the muscle domains must be well known. The utility of late responses like F wave and H reflex is limited in this context. Somatosensory Evoked Potentials are useful to determine continuity from the peripheral to the central nervous system.

Novel genetic mutations in genes AGBL5 and TULP1 for presumed unilateral retinitis pigmentosa managed with low vision rehabilitation: A case report and review

Background: Retinitis pigmentosa is a group of hereditary retinal diseases characterized by the degeneration of rod and cone photoreceptors. It commonly results in night blindness followed by tunnel vision and central vision reduction. The classic triad of clinical signs includes pigmented bone spicules, waxy disc pallor, and arterial attenuation. Unilateral retinitis pigmentosa is rare and can be supported with ancillary testing including genetic and laboratory studies to rule out differential diagnoses. Case Report: A 68-year-old Hispanic female was referred to the low vision rehabilitation clinic due to progressive vision loss in the left eye (OS) that began 15 years ago. The vision was normal in the right eye (OD). Additionally, she suffered from hearing loss in the right ear since age 3. Examination revealed abnormal visual acuity, visual field, fundus appearance, optical coherence tomography, and electrodiagnostic test results in the OS only. Laboratory studies ruled out various infectious, autoimmune, traumatic, and toxic drug etiologies. Genetic testing revealed novel mutations in genes associated with retinitis pigmentosa. Conclusion: The genetic testing results along with the clinical examination and electrodiagnostic evaluation supports the diagnosis of unilateral retinitis pigmentosa.

Complications after open Latarjet procedure: influence of arm positioning on musculocutaneous and axillary nerve function.

Alterations in the anatomical relationships of the musculocutaneous (MCN) and axillary nerves and the influence of arm positioning on these relationships after a Latarjet procedure have been demonstrated in the cadaver, but there are no studies in the literature that establish if there is any neurophysiological repercussion. We retrospectively identified 24 patients with a primary or revision open Latarjet procedure. A prospective clinical (Constant-Murley, Rowe and Walch-Duplay and active range of motion), radiographic (with CT), and electrodiagnostic evaluation was made at the most recent follow-up. Nonunion occurred in four patients (22%); there were, as well, one case of partial coracoid reabsorption (5%) and two (11%) with mild glenohumeral osteoarthritis. In the anatomical position, we found no alterations in the musculocutaneous nerve and two cases (11%) in the axillary nerve slight motor unit loss. In the risk position, 11 cases (61%) had neurophysiological involvement (36% had neurophysiological changes in the musculocutaneous nerve and 64% in the axillary nerve). No differences between patients with or without neurophysiologic changes were found: Constant 87/83; Rowe 89/90; Walch-Duplay 84/78; Forward elevation 175º/170º, abduction 165°/175°; external rotation 48°/45°. The rate of clinical electromyographic changes in the axillary and MCN in the abducted and externally rotated arm position (risk dislocation position) is higher than in neutral position. Nonunion of the coracoid process must play a role in these neurophysiological changes. Although in the medium-term they don't have clinical impact, further randomized prospective studies with a larger sample size are necessary to determine their true repercussion. Level IV.

Assessing Diagnostic and Severity Grading Accuracy of Ultrasound Measurements for Carpal Tunnel Syndrome Compared to Electrodiagnostics

The combined sensory index (CSI) is the most sensitive electrodiagnostic criteria for carpal tunnel syndrome (CTS), and the CSI and Bland criteria have been shown to predict surgical treatment outcomes. The proposed ultrasound measurements have not been assessed against the CSI for diagnostic accuracy and grading of CTS severity. To investigate the use of ultrasound evaluations for both diagnosis and assessment of severity grading of CTS in comparison to electrodiagnostic assessment. All patients underwent an electrodiagnostic evaluation using the CSI and Bland severity grading. Each patient underwent an ultrasound evaluation including cross-sectional area (CSA), the change in CSA from the forearm to the tunnel (∆CSA), and the wrist-forearm ratio (WFR). These measurements were assessed for diagnostic and severity grading accuracy using the CSI as the gold standard. Tertiary academic center. All patients referred for electrodiagnostic evaluation for CTS were eligible for the study. Only those with idiopathic CTS were included and those with prior CTS treatment were also excluded. Ninety-five patients were included in the study. Not applicable. The primary study outcome measure was concordance between CSI diagnosis and severity categories and the ultrasound measurements. Both outcomes were also assessed using Bland criteria. Optimal cut-points for diagnosis of CTS were found to be CSA ≥12 mm2 , ∆CSA ≥4 mm2 , WFR ≥1.4. Using these cut-points, C-statistics comparing diagnosis of CTS using ultrasound measurements versus using the CSI ranged from 0.893-0.966. When looking at CSI severity grading compared to ∆CSA, however, the C-statistics were 0.640-0.661 with substantial overlap between severity groups. Although ultrasound measurements had high diagnostic accuracy for CTS based on the CSI criteria, ultrasound measurements were unable to adequately distinguish between CSI severity groups among patients with CTS.