Diagnostic efficiency of conventional ultrasound, shear wave elastography, and superb microvascular imaging in evaluating ulnar neuropathy at the elbow.

INTRODUCTION/AIMS: The current diagnosis of ulnar neuropathy at the elbow (UNE) relies mainly on the clinical presentation and nerve electrodiagnostic (EDX) testing, which can be uncomfortable and yield false negatives. The aim of this study was to investigate the diagnostic value of conventional ultrasound, shear wave elastography (SWE), and superb microvascular imaging (SMI) in diagnosing UNE. METHODS: We enrolled 40 patients (48 elbows) with UNE and 48 healthy volunteers (48 elbows). The patients were categorized as having mild, moderate or severe UNE based on the findings of EDX testing. The cross-sectional area (CSA) was measured using conventional ultrasound. Ulnar nerve (UN) shear wave velocity (SWV) and SMI were performed in a longitudinal plane. RESULTS: Based on the EDX findings, UNE severity was graded as mild in 4, moderate in 10, and severe in 34. The patient group showed increased ulnar nerve CSA and stiffness at the site of maximal enlargement (CSA mean at the site of max enlargement [CSAmax] and SWV mean at the site of max enlargement [SWVmax]), ulnar nerve CSA ratio, and stiffness ratio (elbow-to-upper arm), compared with the control group (p < .001). Furthermore, the severe UNE group showed higher ulnar nerve CSAmax and SWVmax compared with the mild and moderate UNE groups (p < .001). The cutoff values for diagnosis of UNE were 9.5 mm2 for CSAmax, 3.06 m/s for SWVmax, 2.00 for CSA ratio, 1.36 for stiffness ratio, and grade 1 for SMI. DISCUSSION: Our findings suggest that SWE and SMI are valuable diagnostic tools for the diagnosis and assessment of severity of UNE.

Clinical and neurophysiological recovery of ulnar nerve conduction block at the elbow.

INTRODUCTION/AIMS: An important mechanism of peripheral nerve motor and sensory dysfunction is conduction block (CB). However, recovery from mechanically induced CB has been rarely studied in humans. The aim of this study was to describe clinical, electrodiagnostic (EDx), and ultrasonographic (US) characteristics of CB recovery in ulnar neuropathy at the elbow (UNE). METHODS: We recruited a group of consecutive patients presenting to our EDx laboratory with UNE and >50% motor CB. Patients' histories were obtained and neurologic, EDx, and US examinations were repeated every 1-3 mo for at least 12 mo. RESULTS: We studied 10 patients (5 men), with a mean age of 63 y (range, 51-81 y). In all affected arms CB was localized to the retrocondylar groove. Following conservative management, myometrically measured index finger abduction improved from a median of 49% to 100% relative to the contralateral index finger, and ulnar nerve CB decreased from a median of 74% to 6%. Most of the improvement took place within 8 mo of symptom onset, and 6 mo after receiving treatment instructions. Mean motor nerve conduction velocity improved from 15 to 27 m/s in the most affected 2-cm ulnar nerve segment. DISCUSSION: The resolution of CB after typical chronic compression may take longer than after acute compression. This should be considered by clinicians when estimating prognosis for discussions with patients.

Evidence-based guideline: Neuromuscular ultrasound for the diagnosis of ulnar neuropathy at the elbow.

INTRODUCTION/AIMS: The purpose of this literature review is to develop an evidence-based guideline for the use of neuromuscular ultrasound in the diagnosis of ulnar neuropathy at the elbow (UNE). The proposed research question was: "In patients with suspected UNE, does ulnar nerve enlargement as measured with ultrasound accurately identify those patients with UNE?" METHODS: A systematic review and meta-analysis was performed, and studies were classified according to American Academy of Neurology criteria for rating articles for diagnostic accuracy. RESULTS: Based on Class I evidence in four studies, it is probable that neuromuscular ultrasound measurement of the ulnar nerve at the elbow, either of diameter or cross-sectional area (CSA), is accurate for the diagnosis of UNE. RECOMMENDATION: For patients with symptoms and signs suggestive of ulnar neuropathy, clinicians should offer ultrasonographic measurement of ulnar nerve cross-sectional area or diameter to confirm the diagnosis and localize the site of compression (Level B).

Cutaneous silent period in ulnar neuropathy at the elbow.

INTRODUCTION/AIMS: The cutaneous silent period (CSP) reflects the function of A-delta sensory fibers. There are few studies on CSP in nerve entrapment syndromes. This study aims to evaluate the neurophysiological abnormalities of small-diameter sensory fibers in ulnar neuropathy at the elbow (UNE) by means of CSP. METHODS: We consecutively evaluated UNE patients at one electrodiagnostic laboratory. The CSP was obtained upon stimulating the fifth (D5) and third digits, recording from the first dorsal interosseous (FDI) and abductor pollicis brevis (APB) muscles. RESULTS: We enrolled 37 UNE patients (mean age 55.4 ± 11.2 y) and 30 controls (mean age 51.2 ± 11.1 y). The combinations of the D5-APB and D5-FDI mean onset latencies of CSP were significantly more prolonged in patients (83.7 ± 6.8 and 84.5 ± 8 ms, respectively) than in controls (78.2 ± 8.1 and 79.4 ± 7.6 ms, respectively). The D5-FDI duration of CSP was shorter in patients (52.2 ± 8.3 ms) than in controls (55.8 ± 7 ms). The mean of the onset latencies of D5-FDI and D5-APB was related to the clinical severity (P = .013 and .0025, respectively). D5-APB and D5-FDI onset latencies were more prolonged and the duration was shorter in the UNE group with absent ulnar sensory nerve action potentials (SNAPs) and axonal motor damage than in patients with preserved SNAPs and with demyelinating damage. DISCUSSION: CSP was able to demonstrate abnormalities of small-diameter myelinated sensory fibers. This damage was directly related to UNE severity and to axonal damage of motor fibers. Absence of a sensory large-diameter fiber response did not exclude preserved residual small fiber conduction.

Risk factors of asymptomatic reduction of motor conduction velocity of the ulnar nerve across the elbow.

INTRODUCTION: The aim of the study was to check the risk factors for subjects with motor conduction velocity (MCV) reduction of the ulnar nerve across the elbow without symptoms/signs of ulnar neuropathy at the elbow (UNE) using a database of a previous multicenter case-control study on UNE patients. METHODS: From the previous database, we extracted all asymptomatic UNE (A-UNE) and matched for age and sex with a control and UNE groups with a ratio of 1:2. Anthropometric factors were measured and all participants filled in a questionnaire on demographic, lifestyle factors, and medical history. One-sample proportion test and univariate and multivariate logistic regression analyses were performed. RESULTS: We enrolled 64 A-UNE, 124 UNE, and 124 controls (mean age 53 years). There were more males with A-UNE than females (74.2%). The predominantly or exclusively concerned side of A-UNE was the right. Logistic regression showed that A-UNE was associated with diabetes (OR = 2.99, 95% CI = 1.21-7.39) and width of cubital groove (CGW) (OR = 0.89, 95%  CI = 0.81-0.97). DISCUSSION: Risk factors for A-UNE are different from UNE. The prevalence of right side in A-UNE was not due to particular elbow postures. Diabetes is a risk factor, probably because MCV reduction of the ulnar nerve across the elbow was an early manifestation of asymptomatic polyneuropathy in diabetes. A-UNE is associated with narrow CGW as already demonstrated in UNE, even if the OR was higher in UNE than in A-UNE. Only future longitudinal studies will be able to check whether the A-UNE subjects develop symptoms and signs of true mononeuropathy with time.

Enhancing diagnostic accuracy using a side-to-side cross-sectional area ratio for the diagnosis of unilateral ulnar mononeuropathy at the elbow.

INTRODUCTION: Neuromuscular ultrasonography (NMUS) is a valuable adjunct to electrodiagnostic testing for the diagnosis of entrapment neuropathy. The aim of this study was to determine whether diagnostic accuracy of NMUS could be enhanced in patients with unilateral ulnar mononeuropathy at the elbow (UNE) by utilizing side-to-side ulnar nerve cross-sectional area (CSA) ratios. METHODS: Retrospective case-control analysis of unilateral UNE cases identified cutoff values for elbow segment ulnar nerve maximum CSA (MCSA) of the symptomatic/asymptomatic limb (M ratio), as well as side-to-side ratios comparing MCSA with ipsilateral CSA at the Guyon canal (E/G), middle forearm (E/F), and middle humerus (E/H). Diagnostic accuracy values were calculated. RESULTS: The optimal M-ratio cut-off was 1.22 (sensitivity, 92.9%; specificity, 97.8%; accuracy, 95.4%). Optimal cutoffs for inter-E/G, -E/F, and -E/H ratios were 1.07 (sensitivity, 98%; specificity, 78%; accuracy, 87.7%), 1.11 (sensitivity, 95%; specificity, 80%; accuracy, 87.2%), and 1.18 (sensitivity, 95%; specificity, 93%; accuracy, 94%), respectively. DISCUSSION: The M ratio and inter-E/H ratio exhibited high diagnostic accuracy for unilateral UNE. Prospective studies are needed to compare the accuracy of the new measures with a single MCSA measurement.

Comorbidities, anthropometric, demographic, and lifestyle risk factors for ulnar neuropathy at the elbow: A case control study.

We performed a prospective multicenter case-control study to explore the association between ulnar neuropathy at elbow (UNE) and body and elbow anthropometric measures, demographic and lifestyle factors, and comorbidities. Cases and controls were consecutively enrolled among subjects admitted to four electromyography labs. UNE diagnosis was made on clinical and neurographic findings. The control group included all other subjects without signs/symptoms of ulnar neuropathy and with normal ulnar nerve neurography. Anthropometric measurements included weight, height, waist, hip circumferences, and external measures of elbow using a caliper. The participants filled in a self-administered questionnaire on personal characteristics, lifestyle factors, and medical history. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) by fitting unconditional logistic regression models adjusted by center and education level. We enrolled 220 cases (males 61.8%; mean age 51.7 years) and 460 controls (47.4% males; mean age 47.8 years). At multivariable analysis, UNE was associated to male gender (OR = 2.4, 95%CI = 1.6-3.7), smoking habits (>25 pack-years (OR = 2.3, 95%CI = 1.3-4.1), body mass index (OR = 1.05, 95%CI 1.01-1.10), polyneuropathies (OR = 4.1, 95%CI 1.5-11.5), and leaning with flexed elbow on a table/desk (OR = 1.5, 95%CI 1.0-2.2). Cubital groove width (CGW) turned out to be negatively associated with UNE (OR = 0.80, 95%CI = 0.74-0.85). Our study suggests that some personal factors especially anthropometric measures of the elbow may play a role in UNE pathogenesis as the measures of wrist in CTS. We demonstrated that for each millimeter of smaller CGW the risk of idiopathic UNE increases of 25%.

The needle electromyography findings in the neurophysiological classification of ulnar neuropathy at the elbow

Background/aim: Although ulnar neuropathy at the elbow (UNE) is the second most common entrapment mononeuropathy, there are few reports on its neurophysiological classification. In this study, we tried to find out the role of needle electromyography (EMG) in the neurophysiological classification of UNE. Materials and methods: UNE patients who met the clinical and neurophysiological diagnostic criteria and healthy individuals were included in this study. Reference values of nerve conduction studies were obtained from healthy individuals. Needle EMG was performed to all UNE patients. According to the neurophysiological classification proposed by Padua, UNE patients were classified as mild, moderate, and severe. Results: Thirty-one controls and thirty-five UNE patients were included in the study. There was mild UNE in 23 patients, moderate UNE in 8, and severe UNE in 4. Abnormal needle EMG findings were present in all patients with moderate and severe UNE and in 12 patients with mild UNE. Conclusion: Abnormal needle EMG findings are seen in most of the UNE patients. Therefore, it is not practical to use needle EMG findings in the neurophysiological classification. Needle EMG abnormalities may also be present in patients with mild UNE due to axonal degeneration or motor conduction block.

Neurologic examination and instrument-based measurements in the evaluation of ulnar neuropathy at the elbow.

INTRODUCTION: The aim of the study was to compare the utility of instrument-based assessment of peripheral nerve function with the neurologic examination in ulnar neuropathy at the elbow (UNE). METHODS: We prospectively recruited consecutive patients with suspected UNE, performed a neurologic examination, and performed instrument-based measurements (muscle cross-sectional area by ultrasonography, muscle strength by dynamometry, and sensation using monofilaments). RESULTS: We found good correlations between clinical estimates and corresponding instrument-based measurements, with similar ability to diagnose UNE and predict UNE pathophysiology. DISCUSSION: Although instrument-based methods provide quantitative evaluation of peripheral nerve function, we did not find them to be more sensitive or specific in the diagnosis of UNE than the standard neurologic examination. Likewise, instrument-based methods were not better able to differentiate between groups of UNE patients with different pathophysiologies. Muscle Nerve 57: 951-957, 2018.

A reliable technique for ultrasound-guided perineural injection in ulnar neuropathy at the elbow.

INTRODUCTION: Ulnar neuropathy at the elbow (UNE) is a common peripheral compression neuropathy and, in most cases, occurs at 2 sites, the retroepicondylar groove or the cubital tunnel. With regard to a potential therapeutic approach with perineural corticosteroid injection, the aim of this study was to evaluate the distribution of injection fluid applied at a standard site. METHODS: We performed ultrasound-guided (US-guided) perineural injections to the ulnar nerve halfway between the olecranon and the medial epicondyle in 21 upper limbs from 11 non-embalmed cadavers. In anatomic dissection we investigated the spread of injected ink. RESULTS: Ink was successfully injected into the perineural sheath of the ulnar nerve in all 21 cases (cubital tunnel: 21 of 21; retroepicondylar groove: 19 of 21). CONCLUSION: US-guided injection between the olecranon and the medial epicondyle is a feasible and safe method to reach the most common sites of ulnar nerve entrapment. Muscle Nerve 56: 237-241, 2017.

Complete dislocation of the ulnar nerve at the elbow: a protective effect against neuropathy?

INTRODUCTION: Recurrent complete ulnar nerve dislocation has been perceived as a risk factor for development of ulnar neuropathy at the elbow (UNE). However, the role of dislocation in the pathogenesis of UNE remains uncertain. METHODS: We studied 133 patients with complete ulnar nerve dislocation to determine whether this condition is a risk factor for UNE. In all, the nerve was palpated as it rolled over the medial epicondyle during elbow flexion. RESULTS: Of 56 elbows with unilateral dislocation, UNE localized contralaterally in 17 elbows (30.4%) and ipsilaterally in 10 elbows (17.9%). Of 154 elbows with bilateral dislocation, 26 had UNE (16.9%). Complete dislocation decreased the odds of having UNE by 44% (odds ratio = 0.475; P = 0.028), and was associated with less severe UNE (P = 0.045). CONCLUSIONS: UNE occurs less frequently and is less severe on the side of complete dislocation. Complete dislocation may have a protective effect on the ulnar nerve. Muscle Nerve 56: 242-246, 2017.

Nerve conduction velocity and cross-sectional area in ulnar neuropathy at the elbow.

INTRODUCTION: In the precise localization of ulnar neuropathy at the elbow (UNE) we have noted discrepancies between electrodiagnostic (EDx) and ultrasonographic (US) findings. We aimed to explore the relationship between the 2 techniques. METHODS: Four study-blind examiners took a history and performed neurologic, EDx, and US examinations of a group of prospectively recruited patients with UNE. They assessed the relationship between ulnar nerve cross-sectional area (CSA) and motor nerve conduction velocity (MNCV). RESULTS: In 106 patients with UNE at the retrocondylar (RTC) groove, the highest CSA and lowest MNCV were noted in the same short segment. In 54 patients with UNE at the humeroulnar aponeurosis (HUA), the highest CSA and lowest MNCV were noted proximal to the HUA. DISCUSSION: MNCV and CSA were highly correlated in UNE. Ulnar nerve slowing proximal to the entrapment at the HUA was surprising, but consistent with previous studies done on carpal tunnel syndrome. Muscle Nerve 56: E65-E72, 2017.

Does ulnar nerve dislocation at the elbow cause neuropathy?

INTRODUCTION: The role of ulnar nerve dislocation in the pathogenesis of ulnar neuropathy at the elbow (UNE) is not clear. Data exist for and against a causal relationship. METHODS: We studied UNE patients and controls divided into 4 groups consisting of 203 UNE patient arms (185 with abnormal and 18 with normal diagnostic studies) and 49 controls (10 with abnormal and 39 with normal studies). In all arms we performed neurologic examination, short-segment nerve conduction studies (SSNCS), and ultrasonography (US). The frequency of partial and complete nerve dislocation was calculated in each group. RESULTS: Dislocation tended to be more common in controls compared with UNE patients (P = 0.056). It was particularly common in controls with subclinical UNE and patients with UNE symptoms but normal diagnostic studies. CONCLUSION: Our data speak against a causal relationship between ulnar nerve dislocation and UNE. However, the findings also suggest that dislocation may cause mild ulnar nerve damage.

Is medial elbow pain correlated with cubital tunnel syndrome? An electrodiagnostic study.

INTRODUCTION: Medial elbow pain is often considered to be a symptom associated with ulnar neuropathy at the elbow (UNE). We examined the relationship between medial elbow pain and a positive electrodiagnostic (EDx) test result for UNE. METHODS: We performed a retrospective review of 884 patients referred for EDx evaluation of UNE. Regression models were used to determine the odds ratios between clinical findings and a positive EDx result for UNE. RESULTS: Patients reported medial elbow pain in 44.3% of cases. Clinical factors that correlated with a positive EDx study result for UNE included male gender, small and ring finger numbness, ulnar intrinsic weakness, and age. Medial elbow pain was negatively correlated with a positive EDx result. CONCLUSIONS: This study demonstrates a negative correlation between medial elbow pain and a positive EDx result for UNE. Medial elbow pain should not be considered a clear diagnostic symptom of UNE.

Doppler sonography for ulnar neuropathy at the elbow.

INTRODUCTION: The aim of this study was to determine the value of Doppler sonography for evaluation of ulnar neuropathy at the elbow (UNE). METHODS: A total of 102 patients with a clinical suspicion of UNE and 50 healthy controls were examined by Doppler and gray-scale sonography. RESULTS: Intraneural vascularization was found in 31 (46.3%) of 67 patients with confirmed UNE and in 3 (6.0%) of 50 healthy controls. Combining gray-scale sonography measurement of nerve size and the presence of intraneural vascularization increased sensitivity by 3%, but decreased the specificity. Patients with intraneural vascularization had more severe disease than those without intraneural vascularization (P < 0.05). The variables obtained by Doppler sonography were associated with the severity of UNE (P < 0.05). CONCLUSIONS: Doppler sonography is not helpful for diagnosing UNE but can be used to assess the severity of UNE. Muscle Nerve 54: 258-263, 2016.

Normative values for short-segment nerve conduction studies and ultrasonography of the ulnar nerve at the elbow.

INTRODUCTION: In patients with ulnar neuropathy at the elbow (UNE), short-segment nerve conduction studies (NCS) are rarely performed due to unclear reference values. We excluded controls with subclinical UNE, calculated normative values, and tested them in UNE patients. METHODS: Clinical examination, ultrasonography (US), and 2-cm short-segment ulnar motor NCS across the elbow were performed in 49 controls and 67 UNE patients. In controls, subclinical UNE was diagnosed if at least 2 studies were outside the reference limits in the same 2-cm segment. RESULTS: Exclusion of controls with subclinical UNE produced less stringent normative values (2-cm conduction velocity: 25 to 31 m/s; US cross-sectional area: 11.6 to 9.6 mm2), which raised diagnostic sensitivity (short-segment NCS: 76% to 90%; 10-cm NCS: 72% to 85%, US: 43% to 79%). CONCLUSIONS: We propose the use of our normative values in patients with clinically definite and probable UNE after exclusion of alternative diagnoses.

A randomized trial of diagnostic ultrasound to improve outcomes in focal neuropathies.

INTRODUCTION: Neuromuscular ultrasound is valid, reliable, and accurate, but it is not known whether combining it with electrodiagnostic studies leads to better outcomes in individuals with focal neuropathies. METHODS: One hundred twenty individuals with focal neuropathy, based on history, examination, and electrodiagnosis, were enrolled in this study. All patients underwent neuromuscular ultrasound and were randomized to either have their ultrasound results sent to the referring physician or not have them sent. Outcomes were assessed at 6 months by evaluators blinded to group assignment. RESULTS: The Overall Disability Sum Score and 7 of 8 domains of the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36) showed more improvement in the "report sent" group, although only the general health perception domain was significant (P = 0.005). CONCLUSIONS: Most 6-month outcomes did not reach statistical significance between the 2 groups. However, the "report sent" group had trends toward better outcomes, with significance being reached in the general health perception domain of the SF-36.

Ulnar Neuropathy Caused by a Giant Epidermal Cyst at the Elbow: Case Report.

Here, we report an unusual case of ulnar neuropathy at the elbow caused by a giant epidermal cyst. A 76-year-old man was assessed on an outpatient basis for ulnar numbness of the left hand that had persisted for 6 months. A soft, elastic subcutaneous mass 6 cm in size was noted on his left elbow. He felt numbness on the ulnar aspect of the left fourth and fifth fingers, corresponding to the area innervated by the ulnar nerve, which worsened upon elbow flexion. An electrophysiological study revealed ulnar neuropathy at the elbow. To remove the subcutaneous mass at the left elbow and open up the ulnar tunnel, surgery was performed. There were no signs of nerve impingement or a neuroma on the ulnar nerve. The histological diagnosis was an epidermal cyst. On the day after surgery, numbness on the ulnar aspect of the left hand upon elbow flexion was markedly abated.

Assessing ulnar neuropathy at the elbow using magnetoneurography.

OBJECTIVE: To measure neuromagnetic fields of ulnar neuropathy patients at the elbow after electrical stimulation and evaluate ulnar nerve function at the elbow with high spatial resolution. METHODS: A superconducting quantum interference device magnetometer system recorded neuromagnetic fields of the ulnar nerve at the elbow after electrical stimulation at the wrist in 16 limbs of 16 healthy volunteers and 21 limbs of 20 patients with ulnar neuropathy at the elbow. After artifact removal, neuromagnetic field signals were processed into current distributions, which were superimposed onto X-ray images for visualization. RESULTS: Based on the results in healthy volunteers, conduction velocity of 30 m/s or 50% attenuation in current amplitude was set as the reference value for conduction disturbance. Of the 21 patient limbs, 15 were measurable and lesion sites were detected, whereas 6 limbs were unmeasurable due to weak neuromagnetic field signals. Seven limbs were deemed normal by nerve conduction study, but 5 showed conduction disturbances on magnetoneurography. CONCLUSIONS: Measuring the magnetic field after nerve stimulation enabled visualization of neurophysiological activity in patients with ulnar neuropathy at the elbow and evaluation of conduction disturbances. SIGNIFICANCE: Magnetoneurography may be useful for assessing lesion sites in patients with ulnar neuropathy at the elbow.