Prognostic indicators from electrodiagnostic studies for ulnar neuropathy at the elbow

Introduction: We examined the prognostic value of electrodiagnostic (EDX) studies for ulnar neuropathy at the elbow (UNE). Methods: In this retrospective study, EDX results were compared with subjective recovery (resolution of symptoms) and surgery in patients diagnosed with UNE. Results: Of the 193 patients, 59 with “definite” UNE were included in the analysis. The combination of conduction block across the elbow to the first dorsal interosseous (FDI) and normal distal compound muscle action potential (CMAP) amplitude from the abductor digiti minimi (ADM) was strongly associated with recovery: 86% of these subjects achieved full subjective recovery compared to only 7% without conduction block and with an abnormal CMAP. There were no EDX predictors of surgery. Conclusion: EDX results contain useful prognostic information in UNE. Muscle Nerve, 2011     

Long-term outcomes in patients with ulnar neuropathy at the elbow treated according to the presumed aetiology

Objectives

Ulnar neuropathy at the elbow (UNE) consists mainly of two conditions: entrapment under the humeroulnar aponeurosis (HUA) and extrinsic compression in the retrocondylar (RTC) groove. These in our opinion need different treatment: surgical HUA release and avoidance of inappropriate arm positioning, respectively. We treated our UNE patients accordingly, and studied their long-term outcomes.

Patterns and parameters describing nerve thickening in compression and entrapment ulnar neuropathies at the elbow

ObjectiveTo compare pattern and parameters describing nerve thickening in ulnar neuropathy at the elbow (UNE) due to external compression in the retrocondylar groove (RTC), and entrapment under the humeroulnar aponeurosis (HUA).MethodsIn a group of our previously reported UNE patients we ultrasonographically (US) measured ulnar nerve cross-sectional areas (CSA) on 6–8 standard locations in the elbow segment. We compared CSA patterns in both groups, and determined diagnostic utility of selected CSA based parameters.ResultsWe studied 79 patients (81 arms) with UNE due to external compression, and 53 patients (55 arms) due to entrapment. Maximal ulnar nerve CSA (>16 mm²), maximal CSA change (>7 mm²/1–2 cm) and maximal/minimal CSA ratio (>2.6) were significantly larger in UNE due to entrapment. They also differentiated these arms from arms with compression with sensitivities of 78%, 87% and 80%, and specificities of 90%, 94%, and 85%, respectively.ConclusionMaximal difference in CSA between points separated by 1–2 cm (>7 mm²/1–2 cm) very efficiently differentiated between UNE due to external compression and entrapment.SignificanceThe proposed parameter will hopefully complement precise localization in determining underlying mechanism of UNE. This may help physicians to determine the most appropriate treatment for UNE and possibly other focal neuropathies of unknown cause; i.e., conservative treatment for external compression and surgery for entrapment.     

Relations between sensory symptoms,touch sensation,and sensory neurography in the assessment of the ulnar neuropathy at the elbow

ObjectivesTo evaluate sensitivity, specificity and predictive values of sensory findings in ulnar neuropathy at the elbow (UNE), differences according to UNE localization and pathophysiology, and relation between the sites of sensory symptoms, abnormal evaluation of sensation and neurographic findings of ulnar sensory nerve.MethodsHand diagram and Semmes-Weinstein monofilaments were used for clinical evaluation in four ulnar hand territories. Sensory neurography was measured in the fourth and fifth digits-wrist segments (U5) and in the dorsal ulnar cutaneous nerve.ResultsWe enrolled 75 idiopathic UNE cases and 180 controls. Symptoms in the fifth digit, reduction of touch sensation and U5 sensory nerve action potential amplitude (SNAPa) had the highest sensitivity, specificity and predictivity in UNE diagnosis. The normal/abnormal sensory clinical findings of the fifth digit matched with normal/abnormal U5 SNAP more than the matching of sensory parameters in the other ulnar hand sites. Sensory anomalies were more frequent in predominantly axonal than demyelinating UNE. There were no differences according to UNE location.ConclusionSensory anomalies of the fifth digit are constant findings in UNE more than anomalies of the other ulnar nerve hand regions.SignificanceProbably the fascicles from fifth digit are the most liable to damage at elbow.     

Ultrasonography in ulnar neuropathy at the elbow: Relationships to clinical and electrophysiological findings

INTRODUCTION: Though ultrasonography (US) is commonly used in the diagnosis of carpal tunnel syndrome (CTS), there are only few studies on the utility of US in ulnar neuropathy at the elbow (UNE). The aims of this study were to measure the cross-sectional area (CSA) of the ulnar nerve at the elbow and to correlate CSA values with clinical and electrophysiological findings. PATIENTS AND METHODS: Thirty-three UNE patients (mean age 50.1 years) were consecutively enrolled. Diagnosis was based on clinical findings and slowing of the motor conduction velocity (MCV) of the ulnar nerve across the elbow. CSAs of the ulnar nerve were measured within the cubital tunnel at the level of the medial epicondyle (CSA-M) and approximately 2cm proximal to this point (CSA-I). Correlations between CSA and demographic, clinical (ordinal severity scale and self-administered symptom questionnaire), and electrophysiological findings (neurographic results and ordinal electrophysiological severity scale) were calculated using Spearman's correlation coefficient. RESULTS: The mean CSA-M and CSA-I were 9.6+/-8.5 and 9.3+/-5.6mm2, respectively. Fifteen (45.5%) and eight (24.5%) cases showed abnormal CSA-M and CSA-I values, respectively (mean+2S.D. compared to a control group of the same age). All cases with abnormal CSA-I had abnormal CSA-M except one. Significant relationships were only found between CSA-M and CSA-I with across elbow MCV, sensory action potential amplitude, and the electrophysiological severity scale score. DISCUSSION: Our study showed anomalous CSA values in less than 50% of the UNE cases. This is less than the reported percentages in the few literature reports. This difference may be due to our enrolment criteria or to the electrophysiological and US techniques. It is likely that the CSAs measured by axial scan at a fixed level of the cubital tunnel may have lower diagnostic sensitivity than the same technique used in CTS.     

Apparent conduction block in patients with ulnar neuropathy at the elbow and proximal Martin-Gruber anastomosis

A Martin-Gruber anastomosis (MGA) commonly results in an abnormal decline in amplitude across the forearm segment when ulnar motor nerve conduction studies are performed. A recent report described a proximal MGA resembling partial conduction block in a patient with ulnar neuropathy at the elbow (UNE). As a result, we screened patients with similar findings. We detected a proximal MGA in three patients over a period of 2 years, which suggests that this may be an under-recognized anomaly. We conclude that a proximal MGA must be excluded in all cases of UNE showing apparent partial conduction block across the elbow segment.     

Sonographic incidence of ulnar nerve (sub)luxation and its associated clinical and electrodiagnostic characteristics

Introduction: The aim of this study was to assess the presence of (sub)luxation of the ulnar nerve in patients with ulnar neuropathy at the elbow (UNE) compared with healthy controls (HC). We assessed its clinical patterns, electrodiagnostic, and sonographic characteristics. Methods: Using high-resolution sonography, we studied the incidence of (sub)luxation in a cohort of 342 patients and 70 HC. Results: Subluxation occurred in 14% and luxation in 6.7% of the UNE patients versus 5.7% and 5.7%, respectively, in HC (no significant differences). Pain at the elbow occurred more often in patients with (sub)luxation (P = 0.007). Electrodiagnostic and sonographic findings did not differ between patients with or without (sub)luxation. Conclusions: The incidence of ulnar nerve (sub)luxation between patients with UNE and HC does not differ. UNE patients with (sub)luxation do not have specific clinical or electrodiagnostic findings, apart from experiencing pain at the elbow more often. Muscle Nerve 47: 849–855, 2013     

Electrodiagnosis of ulnar neuropathy at the elbow (Une): A bayesian approach

Introduction: In ulnar neuropathy at the elbow (UNE), we determined how electrodiagnostic cutoffs [across‐elbow ulnar motor conduction velocity slowing (AECV‐slowing), drop in across‐elbow vs. forearm CV (AECV‐drop)] depend on pretest probability (PreTP). Methods: Fifty clinically defined UNE patients and 50 controls underwent ulnar conduction testing recording abductor digiti minimi (ADM) and first dorsal interosseous (FDI), stimulating wrist, below‐elbow, and 6‐, 8‐, and 10‐cm more proximally. For various PreTPs of UNE, the cutoffs required to confirm UNE (defined as posttest probability = 95%) were determined with receiver operator characteristic (ROC) curves and Bayes Theorem. Results: On ROC and Bayesian analyses, the ADM 10‐cm montage was optimal. For PreTP = 0.25, the confirmatory cutoffs were >23 m/s (AECV‐drop), and <38 m/s (AECV‐slowing); for PreTP = 0.75, they were much less conservative: >14 m/s, and <47 m/s, respectively. Conclusions: (1) In UNE, electrodiagnostic cutoffs are critically dependent on PreTP; rigid cutoffs are problematic. (2) AE distances should be standardized and at least 10 cm. Muscle Nerve 49 :337–344, 2014     

Ulnar neuropathy at the elbow: Reappraisal of the wrist-upper arm latency difference between ulnar and median nerves

ObjectivesTo evaluate the sensitivity and specificity of the latency difference (DLat) between ulnar and median nerves of the arm after stimulation at the wrist; one of the easiest techniques proposed for recognizing ulnar neuropathy at the elbow (UNE). As latency difference is not a standardized technique, we set up a multicenter study to recruit large numbers of normal subjects and patients with UNE or generalized neuropathy.MethodsSix centers participated in the study with data obtained from three groups of participants, controls (CTRLs), patients with UNE and patients with generalized neuropathy (GNP).We first verified the anatomical superposition of the ulnar and median nerves in cadaver examination. The optimal recording site for these two nerves was found to be 10 cm above the medial epicondyle. We then standardized the position of the arm with full extension of the elbow and stimulated first the median and then the ulnar nerves at the wrist. CTRLs were examined on both arms at two consecutive visits.ResultsWe recorded 32 idiopathic UNE cases, 44 GNP patients and 62 controls.We demonstrated that a DLat cut-off value of 0.69 ms brings a sensitivity of 0.86 and specificity of 0.89 to discriminate CTRLs from UNE. We also validated that intra-examiner reproducibility was good.ConclusionWe report a lower normal value for DLat than reported in several non-standardized studies and CTRL and UNE groups have clearly separated DLat values.SignificanceDue to its high sensitivity, our standardized technique could be used as a first-line diagnostic tool when UNE is suspected.     

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     

Localization of ulnar neuropathy with conduction block across the elbow

We performed short segment incremental stimulation on 13 consecutive patients with ulnar neuropathy across the elbow (UNE) and conduction block. Conduction block occurred proximal to the medial epicondyle in 62%, at the epicondyle in 23%, and below the elbow in 15%. The ulnar nerve may be more prone to external compression above the elbow than previously recognized. Short segment incremental studies are useful to identify conduction block above the elbow in such patients.     

Ultrasonographic swelling ratio in the diagnosis of ulnar neuropathy at the elbow

High-resolution ultrasound can demonstrate focal nerve enlargement in entrapment neuropathies. We hypothesized that a ratio between the nerve cross-sectional area at the site of maximal enlargement and at an unaffected site may improve diagnostic accuracy in ulnar neuropathy at the elbow (UNE), when compared to a single measurement at the site of maximal enlargement. Ultrasound was used to measure the cross-sectional area of the ulnar nerve at three sites in 30 normal, healthy controls and 26 individuals with UNE. In individuals with UNE, the ratio was 2.9:1 when the site of maximal swelling was compared with a distal ulnar nerve site and 2.8:1 when compared with a proximal site. This represented a significant increase compared with the ratio of 1.1:1 for both comparisons in controls (P < 0.0001). This type of ratio may be particularly useful for assessing entrapment in those with polyneuropathy or obesity, both of which can cause diffuse nerve enlargement.     

Differentiation of ulnar neuropathy at the wrist due to ganglion cyst from ulnar neuropathy at the elbow

ObjectiveHere, we aimed to describe the clinical, electrodiagnostic (EDx) and ultrasonographic (US) findings in a series of patients with ulnar neuropathy at the wrist (UNW) due to compression by a ganglion cyst. We also sought features that differentiate UNW from ulnar neuropathy at the elbow (UNE).MethodsWe reviewed electronic medical records of consecutive patients with UNW caused by ganglion cysts. We compared their clinical, EDx and US findings to findings in our previously reported prospective series of UNE patients.ResultsWe identified 10 patients with UNW caused by ganglion cyst compression, who all presented with intrinsic hand muscle weakness and atrophy. Compared to 175 UNE patients they less often complained of paresthesia (60% vs. 98%) and presented less sensory loss in the palm (30% vs. 96%) and little finger (50% vs. 95%). They more often had distal ulnar motor latency recorded from the abductor digiti minimi (ADM) > 3.6 ms (80% vs. 30%), and denervation activity on needle EMG in the first dorsal interosseous (FDI) compared to ADM (100% vs. 60%). Only 20% of our UNW patients had ulnar nerve swelling at the site of compression on US.ConclusionUNW potentially caused by ganglion cyst should be suspected in patients presenting with intrinsic hand muscle atrophy and weakness, particularly in cases with normal sensation, increased distal ulnar motor latency recorded from ADM and more severe neuropathic changes in FDI compared to ADM muscle.     

Effect of body mass index on ulnar nerve conduction velocity, ulnar neuropathy at the elbow, and carpal tunnel syndrome

Both high and low body mass index (BMI) have been reported as risk factors for ulnar neuropathy at the elbow (UNE), and a high BMI as a risk factor for carpal tunnel syndrome (CTS). To determine whether the extremes of BMI are risk factors for UNE or CTS, and whether BMI affects calculation of median and ulnar motor nerve conduction velocity (NCV), we retrospectively analyzed the electrodiagnostic records of control patients, UNE patients, and CTS patients. The BMI was calculated for 50 patients with a sole diagnosis of UNE and compared to the BMI of 50 patients with CTS and 50 control subjects. The mean BMIs were 25.9 +/- 4.4, 30.1 +/- 5.5, and 28.3 +/- 5.6 for the UNE, CTS, and controls, respectively. By one-way analysis of variance, the difference in BMI between the UNE patients and the normal patients was significant (P < 0.01). In the control groups, increasing BMI directly correlated with increasing ulnar motor NCV across the elbow but not with forearm NCV. Across-elbow (AE) ulnar motor NCV may be falsely increased in patients with a high BMI, probably due to distance measurement factors. Not only do relatively slender individuals have comparatively slower AE ulnar NCVs, they are also at increased risk for developing UNE. Patients with a high BMI are at increased risk for CTS.     

Which motor nerve conduction study is best in ulnar neuropathy at the elbow?

There is debate regarding how best to utilize ulnar motor nerve conduction velocity (MNCV) to identify ulnar neuropathy at the elbow (UNE). We used receiver operator characteristic (ROC) curves to compare absolute across-elbow MNCV with MNCV difference between elbow and forearm segments (VDIF) when recording from abductor digiti minimi (ADM) and first dorsal interosseous (FDI) muscles. Also, we determined how their utility was impacted by low amplitudes of compound muscle action potentials (CMAPs). We studied 85 subjects with UNE and 77 subjects with carpal tunnel syndrome but without clinical evidence of UNE. The UNE group was divided into three subgroups based on CMAP amplitude. At 95% specificity, MNCV sensitivities were 80% at ADM and 77% at FDI, and VDIF sensitivities were 51% at ADM and 38% at FDI. The ROC curves showed MNCV to be superior to VDIF across all amplitude subgroups; however, confidence intervals overlapped when amplitude was high.     

Cold elbow syndrome: spurious slowing of ulnar nerve conduction velocity

Low temperature decreases nerve conduction velocity (NCV). The across-elbow segment of the ulnar nerve is superficial and may be particularly susceptible to decreased temperature. We evaluated patients without clinical ulnar neuropathy at the elbow (UNE) but with isolated slowing of the across-elbow ulnar NCV (normal group), and patients with clinical and electrodiagnostic findings of UNE (UNE group). All subjects had ulnar motor nerve studies completed before and after warming. The mean across-elbow NCV was 43.4 m/s and 48.6 m/s (P < 0.0001) in the normal group, and 37.4 m/s and 37.7 m/s (P = 0.90) in the UNE group, before and after warming, respectively. There was no change in the forearm segment NCV in either group. Seventeen of 32 subjects in the normal group had completely normal studies after warming. No patients with UNE developed normal across-elbow NCV with warming. Low temperature slows across-elbow ulnar NCV in normal subjects without impact on the forearm segment. Warming of the elbow improves across-elbow ulnar NCV in normals, but does not reverse the abnormalities in patients with UNE. Elbow warming should become a routine part of ulnar nerve conduction studies, especially when there is isolated conduction slowing in the across-elbow segment.     

Comparison of electrodiagnosis,neurosonography and MR neurography in localization of ulnar neuropathy at the elbow

IntroductionIn patients with ulnar neuropathy at the elbow (UNE) the precise determination of the site of lesion is important for subsequent differential diagnostic considerations and therapeutic management. Due to a paucity of comparable data, to better define the role of different diagnostic tests, we performed the first prospective study comparing the diagnostic accuracy of short segment nerve stimulation, nerve ultrasonography, MR neurography (MRN), and diffusion tensor imaging (DTI) in patients with UNE.MethodsUNE was clinically diagnosed in 17 patients with 18 affected elbows. For all 18 affected elbows in patients and 20 elbows in 10 healthy volunteers, measurements of all different diagnostic tests were performed at six anatomical positions across the elbow with measuring points from distal (D4) to proximal (P6) in relation to the medial epicondyle (P0). Additional qualitative assessment regarding structural changes of surrounding nerve anatomy was conducted.ResultsThe difference between affected arms of patients and healthy control arms were most frequently the largest at measure intervals D2 to P0 and P0 to P2 for electrophysiological testing, or measure points P0 and P2 for all other devices, respectively. At both levels P0 and at P2, T2 contrast-to-noise ratio (CNR) of MRN and mean diffusivity (MD) of DTI-based MRN showed best accuracies.DiscussionThis study revealed differences in diagnostic performance of tests concerning a specific location of UNE, with better results for T2 contrast to noise ratio (CNR) in MRN and mean diffusivity of DTI-based MRN. Additional testing with MRN and nerve ultrasonography is recommended to uncover anatomical changes.     

A self-administered questionnaire of ulnar neuropathy at the elbow

Abstract We report a new self-administered questionnaire for assessment of symptom severity of ulnar neuropathy at the elbow (UNE). The new UNE and Levine's questionnaires were administered to a sample of UNE subjects and for comparison also to a sample of subjects with carpal tunnel syndrome (CTS). We enrolled 89 consecutive patients (32 women, 57 men, mean age 52.3 years) with UNE and 203 consecutive patients (157 women and 46 men, mean age 53.7 years) with CTS. The protocol of the study consisted in self-administration of the new UNE and Levine's questionnaires, as well as scoring of clinical and electrophysiological severity of entrapment syndromes with ordinal scales. The UNE questionnaire (UNEQ) includes nine questions and considers numbness and tingling in the fourth and fifth fingers, elbow pain and modification of pain and paraesthesia with elbow position. A score from 1 (absence of symptom) to 5 (most severe) is assigned for each question. The overall score is calculated as the mean of the nine scores. Test–retest reliability, internal consistency and validity were assessed. Responsiveness was also tested in a sample of patients undergoing conservative treatment. The UNEQ was reproducible. Spearman's correlation coefficient between scores at successive observations (test–retest reliability), assessed in the first 44 patients, was 0.97 and Cohen coefficients κ for single items were between 0.64 and 0.81. Internal consistency was high: Cronbach's α, which summarises interitem correlations among all items of UNEQ, was 0.87. Validity was demonstrated by a direct correlation with UNE clinical and electrophysiological severity scores (0.65 and 0.35). On the contrary, Spearman's correlation coefficients between UNEQ and clinical and electrophysiological CTS severity scores were low (0.11 and 0.02, respectively). Responsiveness was calculated at 6–8 months follow-up in 25 cases. The effect size was 0.46. The Wilcoxon rank-test showed significant improvement between basal and follow-up UNEQ scores (Z=–2.39, p=0.017), but not Boston Questionnaire scores. There was also significant correlation between UNEQ changes and an arbitrary scale of patient satisfaction at follow-up (r=0.85, p<0.001). The UNEQ is reproducible, internally consistent and valid. Although further studies are required to test its responsiveness to clinical changes, UNEQ may be also considered responsive. UNEQ can be used to measure subjective discomfort in UNE patients.     

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     

Clinical, electrodiagnostic, and sonographic studies in ulnar neuropathy at the elbow

The aim of this study was to determine possible correlations between the clinical characteristics, electrophysiological features, and sonographic ulnar-nerve diameter in patients with ulnar neuropathy at the elbow (UNE). We prospectively performed clinical, electrodiagnostic, and sonographic studies in 102 patients having either purely sensory signs (35%) or sensorimotor signs (65%) of UNE. Nerve conduction studies had a sensitivity of 78%, and the addition of sonography increased this to 98%. The diagnostic value of both tests was not different among cases with and without motor deficit. Motor studies with recording from the abductor digiti minimi and first dorsal interosseous muscles were equally sensitive for the detection of conduction block or velocity slowing across the elbow, but the combination yielded more positive cases than when only one study was performed. There were modest negative correlations between the electrodiagnostic parameters and the sonographic ulnar-nerve diameter. Electrodiagnostically and sonographically, there were no significant differences between clinically pure sensory and mixed sensorimotor cases of UNE, except for electrodiagnostic findings suggesting loss of motor axons in cases with motor signs. Almost half the patients with only sensory signs had electromyographic evidence of motor axonal loss. We conclude that, although UNE is clinically heterogeneous, the electrophysiological and sonographic findings are fairly consistent despite the clinical manifestations.